Public Access Copy DO NOT REMOVE from room 208. STATE OF DELAWARE
DELAWARE GEOLOGICAL SURVEY
BULLETIN NO.6
VOLUME 1
THE WATER RESOURCES OF NORTHERN DELAWARE
by WILLIAM C. RASMUSSEN JOHAN J. GROOT ROBERT O. R. MARTIN EDWARD F. McCARREN VAUGHN C. BEHN and others
Newark. Delaware June, 1957 STATE OF DELAWARE DELAWARE GEOLOGICAL SURVEY BULLETIN NO.6 VOLUME 1
THE WATER RESOURCES OF NORTHERN DELAWARE
by
William C. Rasmussen District Geologist, U. S. Geological Survey
Johan J. Groot State Geologist of Delaware
Robert O. R. Martin Hydraulic Engineer, U. S. Geological Survey
Edward F. McCarren Chemist, U. S. Geological Survey
and others
Prepared in cooperation between the Delaware Geological Survey the Delaware State Highway Department and the Geological Survey United States Department of the Interior
with a section on
PROBLEMS OF WATER MANAGEMENT by Vaughn C. Behn Associate Professor of Civil Engineering University of Delaware
Newark, Delaware June, 1957 DELAWARE GEOLOGICAL SURVEY
University of Delaware
Newark, Delaware
Members of the Delaware Geological Commission
John R. Ennis Odessa
John R. Hitchens Georgetown
Clayton M. HoU Wilmington
John A. Perkins Newark
G. Preston Ward Dover
StaU of the Delaware Geological Survey
Johan J. Groot • State Geologist
Richard F. Ward Geologist
Robert M. Germeroth Geologist
Marilyn D. Maisano Geologist
Maraaret B. Nelson Secretary
StaU of the cooperative Ground-Water Program
U. S. Geological Survey
William C. Rasmussen. District Geologist
Catharina R. Groot Geologist
Durward H. Boggess • Eagineering Aid
Oscar J. Coskery • • Engineering Aid
Betty J. Linehan Secretary
3 STATE OF DELAWARE DELAWARE GEOLOGICAL SURVEY UNIVERSITY OF DELAWARE NEWARK, DELAWARE
GEOLOGICAL COMMISSION:
JOHN R. ENNIS, ODE••A JOHN R. Hn'CHENS. w.ORw.TOWN CLAYTON M. HOF'JI', WILMINGTON JOHN A. PERKINS, NEWARK PRESTON WARD, DOYER
.lOMAN J. GROOT, STATE GEOLOGIST TEL. ENDICOTT SaSS' I. EXT. 342
June 30, 1957
The Honorable J. Caleb Boggs Governor of Delaware State House Dover, Delaware
Dear Sir:
I have the honor to sumit to you Bulletin No. 6 of the
Delaware Geological Survey. This report contains an evaluation of the surface water and ground water resources of Delaware north of the Chesapeake and Delaware Canal.
Respectfully yours,
John A. Perkins President University of Delaware THE WATER RESOURCES OF NORTHERN DELAWARE
ABSTRACT PREFACE
Northern Delaware. the area above the Chesapeake and Dela In this report, greater emphasis has been given to an e;;aluation ware Canal in New Castle County, is an area of rapidly growing of surface-water resources than was customary in the pr-evioue bul population and expanding industry. In some places the demand for letins of the Delaware Geological Survey. It was felt that the rapid water has reached or exceeded the capacity of the existing facili increase in water use now taking place in New Castle County north of ties. creating apparent water shortages. Many agencies, both public the Chesapeake and Delaware Canal might lead to the full utilization and private, are attempting to alleviate these shortages; studies are of the ground-water resources of that area in the near future an~that, being made and reports prepared lor immediate action as well as consequently, special attention should be devoted to the. quantlty~d long-term planning. It is the purpose of this report to examine on quality of water in the streams of northern Delaware WIthOUt aa cr r a long-range basis the water resources of the northern Delaware ficingthe study of ground-water supplies. As a result, a more "~al area. anced" report has emerged, which, it is hoped, will be of pr~ctlcal use to all those who are engaged in developing water supphes for This examination indicates that the surface-water and ground municipal, agricultural, or industrial use. water resources of the area far exceed the 72.,.8mgd (million gallons per day) used during 1955. The amount of ground water potentially The writers' primary objective was to make an estimate of the available in the area is estimated to be at least 30 mgd and the a potential water resources of northern Delaware. Potential water r~ mount of surface water potentially available depends principally on sources are those which would be available.!!. the maximum practl the amount of storage that may be feasible economically. Storage cable storage capacity could be constructed, and if wells could be of 3 million gallons per square mile would provide an allowable spaced in such a manner that ground-water reservoirs would produce draft rate of 140 mgd with a deficiency at average intervals of ten their optimum yield. Therefore, problems on the ~anagementof years, while storage of 30 million gallons per square mile would water resources are introduced, the solution of whi ch may pre raise the allowable draft to 250 mgd, which is about half of the mean sent difficulties of an economic and political nature. Although it is annual discharge. In addition to the fresh-water resources, saline outside the scope of this report to make reconunendations as to the water from the Delaware River and its tidal estuaries is available solution of such problems, Dr. Behn's discussion entitled, "Prob in almost unlimited quantity for cooling, fire fighting, some types lems of Water Management, " should prove'helpful to those who are of washing, and other purposes. concerned with these problems. Ground water, utilized at an average rate of 11 mgd in northern Delaware in 1955, a little less than one-sixth of the total rate of fresh-water use, is a water of premium quality and nearly constant temperature and is highly valuable for specialized purposes. It is, fortunately, available in relatively large quantities on the Coastal Plain, where surface water is relatively difficult to develop. There are 10 principal aquifers, or ground-water reservoirs, in northern Delaware, defined on the basis of the local geology. Three of the ten are of major importance--that is, capable of sustained yields of several million gallons a day of water of good to excellent quality. It is estimated on the basis of an average precipitation of 44. 1 in ches a year, or Z.13 million gallons a day per square mile, and estimated percentages ofinfil tration, that the amount of fresh ground water available in northern Delaware is between 25 and 50 mgd.
Except for the saline water, the quality of the water in northern Delaware is generally good. Chemical. contamination of the ground water has occurred in five restricted localities, and stream waters
6 7 are generally polluted. Both chemical contamination and organic pollution have abated, however. The waters .of the major streams C;:ONTENTS that drain the Piedmont are moderately hard. The ground waters beneath the Coastal Plain contain iron in slight to troublesome a mounts. In all other respects, the fresh waters of the area are INTRODUCTION, by J. J. Groot, W. C. Rasmussen, and suitable for most purposes with little or no treatment. R. O. R. Martin •••...... ••••.•••..•••••••••••••••••. 19 Purpose and scope of the investigation .••••••••••..••••••• 19 In spite of the potential availability of large quantities of water, Des cription of the area -,••••••••.•••••••••••••••••••••• 20 complacency is not warranted. To develop even the 140mgdof sur Topography and drainage •••••••••••••••••••.•••••••• 20 face water estimated to be available at reasonable cost would require Regional geology .••••.•••••••••••••••••••.•••••••••• 22 construction of several moderate - sized reservoirs at strategic sites Climate ...... 23 in the Christina River system (Brandywine Creek, Red Clay Creek, Population ...... ••.•...... "...... •.•...... 23 White Clay Creek, and the main branch of the Christina River). Previous investigations ....•.•...•....•...... •.•.... 24 Studies of available reservoir sites on these streams would have to Personnel and acknowledgments .•••••.••••••.•.•••••••• 25 begin soon if the supply were to be needed within a decade or so. SIGNIFICANCE AND SOURCES OF WATER, by W. C. Rasmussen, E.F. McCarren, andNs H, Beamer ...... 27 Although ground water could support a draft at least three times Hydrologic cy.cle ...... •.•....•.•.....•... o •••••••••• 27 as great as the rate of use in 1955, to approach full development Sources of water ...... •.•..•.••...... ••.... 30 will involve numerous test-well failures, owing to the difficulties Fresh surface water .•••••••••••••••••..•••.•••••••• 30 of predicting good well locations in the channel-type silty sands which Ground water .•..•••••••••••••••••••••••••••••••.•••• 30 predominate in the Coastal Plain of northern Delaware. Careful Saline water •.•••••••••.•••••••.••••••••.••••••••••• 31 study of the local geology and the use of modern geophysical-pro Significance of water quality .••••••••••••••••••••••••••. 32 specting and drilling methods will be necessary to r educe prospecting SURFACE WATER, by R. O. R. Martin and A. E. Hulme 35 sai.lur e to a rn irrirnurn~,..,-~, The danger of aalt -wate r encroachment into General principles .•...... ••.•...... •...... ••.... 35 the heavily pumped well fields is ever present in most of northern Definition of terms ...•.•...••.••.•...... 0 •••••••••••• 35 Delaware. Hydrologic evaluation, using water-level and quality-of Records available ...... 36 water data obtained Erorn outpost wells, will be necessary in order Flow characteristics ...... •...... 45 to adjust future pumping rates to restrain encroachment. Low flows ...... ••.•...... ••..... 45 Flow-duration curves .....••••...•....••.•.•..•...••• 47 Low-flow frequency curves ...... •.•.•....••.•.. 50 Days of deficient discharge •.•••••••••••••••••••••• 50 Storage required frequency .••..•.•.•....••••.•.•.. 55 Flood flows ••.••••••••••••••••••••••••••••••••••••• 55 Flood-frequency relations •••••••••••••••••••••••••••• 55 Evaluation by basins ..•••..•••.•.•...... •.•..••..... 63 Delaware River ...... 66 Naaman Creek ...... •..••.•...... •..•.....••••.. 66 Stoney Creek and other small Piedmont tributaries to the Delaware River ....•••••.•.••.•....•••••...•..•.••. 67 Christina River basin .••...... •.•.•..•..•..•...••.•• 67 Shellpot Creek ...•.••.•.•...... •..•.•••.•.•••.• .. 67 Brandywine Creek ..•.•...... •.•...... •... •. 68 Red Clay Creek .....•••..•....•..•...•.....••.•.••. 69 White Clay Creek above Newark •••••••••••••••••••• 70 White Clay Creek below Newark •••••••••••••••••••• 72 Christina River above tidal effect .••••••••••••••••••• 74 Small stream basins in the Coastal Plain .••••.•••••••••. 75 Tributary to Delaware River •• ••••••.••••••.•••••• •• 75 Tributary to Chesapeake and Delaware Canal •••••••• 75 8 9 1 CONTENTS CONTENTS
SURFACE WATER--Continued. QUALITY OF WATER •••••••.••..•.••..•.••••...•.•••••. lZ8 Evaluation by basins--Continued. General principles of water quality, by E. F. McCarren
Small stream basins in the Coastal Plain--Continued. and N. H. Beamer •.•.•••••••••.•••••.••.. ~•.•••••..• lZ8 Tributary to Chesapeake Bay .••••••••••..••..••••••. 75 Color •••.••••.••••.••....•.••.••••••••••••.•...•.••• lZ9 Estimated average dis charge ...••....••••••••.•••••• 75 Hydrogen-ion concentration (pH) .•••..••.•.•••••••••••• lZ9 GROUND WATER ...... 77 Specific conductance (micromhos at Z50C). " •••••••••••• 130 General principles, by W. C. Rasmussen •••••••••••.•••• 77 Silica (SiOz) ••••••••••••••••••••••••••••••••••••••• 130 Ground-water hydraulics .••.•.••.•...••.•••.••...••. 77 Aluminum (Al) .•..••.•••..••••.•.••.•.••••.•••••••.•. 130 Wells and springs ....•.••.••...... •..•...••••••. 8Z Manganese (Mn) ••.•.•.•••.••••••••.••••••••••...•• 130 Fluctuations of water level .••.•..•...... ••. 89 Iron (Fe) .•.•.•...••.•••.••••••..••.•..•....•.••• •.• • 131 Geologic formations and their water-bearing characteristics. 90 Calcium. (Ca) ....•...••.•••••...•..•••••.•••••.••••• 131 Crystalline rocks and their weathered products, by Magnesium" (Mg) ••••••••••••••••••••••••••••••••••• 131 R. F. Ward and W. C. Rasmussen ...... •..•..... 93 Sodium and potassium (Na and K) ••••••••••••••••••• l3Z Rocks of the Piedmont 97 Bicarbonate (HCO3) .•••.••....•.•...... •••.•.•••••...• 13Z Metasediments .....••.•..••.•••. '.•.•••••.•••••.••. 99 Carbonate (COZ) •.••••.•.••••.•••.•••..••.•.••.•.•• 13Z Cockeysville marble .....•....••...•..••••.•• ~.. 100 Sulfate (S04) ..•••••.•.•..••••••.••••••.•.••••.•••.• 13Z Wis sahickon formation ..•.••....•••.••.•••..•. 10Z Chloride (CI) ...•.••.•.••••••.••••.•••••.•.•.•••••..• 133 Intrusive igneous rocks ...•••••••...••.•••••.••..•• 104 Fluoride (F) .•••••.•.••.•••....•.•••..•••.•.••...•• 134 134 Gabbro I" •••••••••••••••••••••••••• 104 Nitrate (N03) ..•.•..••••.•.••••••.••.•.•••••••••.•.• Granodiorite ..••••••••••.•.••••.••.••••••••...•. 106 Dissolved solids ••••••.••••••••..••.•.•••.•••.•••.. 134 Pegmatite •••.•••.•••.••••••••.••••••••••••••• 106 Hardness ••••.•••••••••...•••.•••••••.•••••••..••••• 135 Serpentine ••.•••.•••••••••••••••••.•••••..•••• 106 Total acidity ...•..•••.•.•••••••.••.•••••.•••..••••. 136 Basement rocks of the Coastal Plain •••••••••••••••• 107 Chemical quality of streams, by E. F. McCarren ••••••• 136 Sedimentary rocks of the Coastal Plain, by J. J. Groot South Branch Naaman Creek at Arden . 138 and W. C. Rasmus s en ..••.•••••.•••••••..••.••.•• 107 Christina River 'basin ••••••••••••••••••••••••••.••••• 138 Cretaceous s ys tern •.••••.•••.•.•...••.•••••••••.•. 110 Shellpot Creek at Wilmington .•••••••••••••••••••••• 138 Nonrn.arine sediments •.••••••.••••...••••.••••••. 110 Brandywine Creek at Wilmington ••••••••••••••••••• Lower aquifer ••••••..••••••.•.•••..•••••••••• III Red Clay Creek at Wooddale ••••••••••••••••••••••• 14Z Middle aquife r .••.••••••••••.••••.•.••.••.•.•• lIZ White Clay Creek .•...•••••.••••..•...•••.•.•••. l4Z Upper aquifer .•••..•.••.••••.•.••.•••.•.••••• 114 Above Newark ••••...••••••••••.••.•.•••••.••• •,.. 144 Transitional sediments, Magothy formation •••••••• 115 Below Newark .••...•.••.•.••..•••••••••.••••...• 144 Marine sediments .••.•.••••..••.•...•.•••••••.... 116 Mill Creek at Stanton .••.•••••..•••••.••••••..•• 144 Merchantville clay, an aquiclude •••••••••••••••• 116 Christina River at Coochs Bridge ••••••••••••••••••• 146 146 Wenonah sand, amino r aquifer .•••••••.••••••• 118 Small stream basins on the Coastal Plain •••••••••••••• Mount Laurel sand and Navesink marl undiffer- Red Lion Creek at Red Lion .•.•••.•.•.•.•••••••••. 146 entiated, an aquiclude ..•••..•••.••••••••••••• 118 Saline wate r ..•.••••••••••••••.•.••••..••.•.•.•.• ••••... 146 Red Bank sand, locally an aquifer •• ••••••••••••• 119 Delaware River, by E. F. McCarren ••••••••••••••••••• 148 Tertiary(?) system .••.••••.••.••••.••••••.•••.•.•• 119 Tributary estuaries, by W. C. Rasmussen •••••••••••••• l5Z Upland sediments ..•••.••.•.•..••.••.••••.•.•.••• lZO Naaman Creek at Claymont .•.•••••..•.•.•••.••.•• l5Z Pliocene series, Bryn Mawr(? ) gravel, a minor Christina River .•.•..•.•.•...•••.••..•..•••.••.••• 154 aquifer .••.••.•••••••••••••••••••..•••••.•• lZO Tidal streams of the Coastal Plain •••••••••••••••• '••• 154 Quaternary system .••.•••••..•••••.•.•.••••.••.••• lZl Chesapeake and Delaware Canal, by W. C. Rasmussen Sediments beneath the coastal terraces •••••••••••• lZl and N. H. Beamer •••••••.••••.••.•••••••..•••••• 154 Pleistocene series, an important aquifer system ••• lZZ Chemical quality of ground water, by W. C. Rasmussen 154 156 .Alluvium, a minor aquifer lZ6 Rocks of the Piedmont .•.••••.••••••.••..•••••••••••• .•.•••••••.•••••.•••.••. 156 Recent series lZ7 Cockeysville marble .••..•••....•.••••.••••.•••••...... 11 10 CONTENTS CONTENTS
QUALITY OF WATER--Continued. WATER UTILIZATION--Continued. Chemical quality of ground water--Continued. Institutional water systems ••••.••••••••••.••.•.•.••.• 185 Piedmont rocks--Continued. Delaware State Hospital .•..••••.••••..•••••••••..••••• 185 Wissahickon formation 156 New Castle County Airport •.•.•.••.•...•••..••••••••• 186 Gabbro - .. 158 Governor Bacon Health Center .••••••.•••.••.•••••••••• 186 Granodiorite .. 159 Other institutions 186 Coastal Plain sediments .. 159 Rural water supplies •..•.•••••••..•• ' . 186 Nonmarine Cretaceous sediments •••••••.••••••••••• 159 POTENTIAL DEVELOPMENT, by W. C. Ras.mussen and Lowe r aquife r .. 159 R. O. R. Martin .•...•..•.•.•.••.•••..•..••.•••••••••.• 188
Middle aquifer II .. 16Z Surface water ...... 190 Upper aquifer .. 163 Ground water ...... 19Z Magothy formation ...... 163 Saline-water reserve •••••.••••••••••.••.•.•••••.••••••• 194 Marine Cretaceous sediments .. 163 CONCLUSIONS ..••.•.•.•.•••••.•••••.•••••••..••.•.••••.• 196 Pleistocene series ...... 166 REFERENCES .•..•..•..••••••••••.••••.•.•.••.••••••••.. 198 Intrusion and contamination .. 168 PROBLEMS OF WATER MANAGEMENT, by Vaughn C. WATER UTILIZATION, by D. H. Boggess ••••••••••••••••••• 172 Behn .••••••...•....••.•••.•.•.•••..•.•.••••.••••••• Z04 Municipal systems .. 174 Water requirements ..•.•.••••.••••.•.•...••.••••••••.• Z04 Wil:rnington .. 176 Development of water sources .•.•.•••••....•..•.•.• •_•••.• Z06 Newark . 176 Ground water ..•.•.•.••••••.•.•.••••••••••..•••••••• Z06 New Castle .••....•••••••..••••••...•.••• '.•.•.••.. 177 Surface water ..•.•.••.••••.•••••••.••••••••.•.•..•.. Z07 Newport ...•....•...•••.•.••••••••...•.•..•.•.•..•• 178 Water treatment and distribution .•.••.•••••.•...••.••.. Z10 Large privately owned systems ••..•••••...•..••...•..•.• 178 Water treatment .••.•....•••••••.•••••.....•.•..... Zl1 General Waterworks Corp. • ••••••••.•.•..•.•.••.••••. 179 Water distribution .•••..••. •-•••..••..••...•..•.•.•••• Zl1 Delaware Water Company .•.••..•.•••••..•••..•..•.. 179 Financial and legal aspects ,.••••••.••••.•...••••...•.•... Z15 Wilmington Suburban Water Corp. • •••••••••••••••••• 179 Financial aspects ..•••••••••••••..•.•.•.•..•...•••.. Z15 Arden Water Co. . ..•.••.•.•. , •..•..•....••..••..• 180 Legal aspects .••.••.•••.•••.••..••..•••...••.•.••... Z17 Artesian Water Co ....••••.••• ~.•..•...•.•.•••.••...• 180 Summar y .••.•..•••••••.•.•....• '•...... •...•.•....•.•• ZZO Delaware City Water Co ••.•••.•..•.••...•.•••••••...• 181 References ZZZ Collins Park Water Co .•••..••.•.••...•.••.•...... ••• 181 Willow Run, North Star, and Sedge1y Farms Water Cos ••• 181 New Castle County Water Co ...••••...•••.•.•..•...••• 181 Industrial water systems ••••••..•••••••.••....••••.•..• 18Z Surface-water supplies .••••.•••••••..••••••.•.•.••••• 18Z Brackish-water use ...... 18Z Fresh-water use .••••••••.•.•.•••.•••...•••.••.•••. 183 Ground-water supplies ...••••••••••••••.••••.•••••••• 183 Atlas Powder Co. .• • •.•••.••••.•••.••....•.•••..•• 183 Mohawk Carpet Mills, Inc. . . 183 Tidewate rOil Co. . ••.••••••••..•..•••.••.•.••.•..• 184 Richmond Radiator Co. • •••••••.••••••••..•.•..••••. 184 Hercules Powder Co •••.•.••.•.•••.•.••••..•••.••.• 184 DuPont Co. . •.•..•.•.•••.••••...•.•..•.•.••.•..•.• 185 Ludlow Manufacturing and Sales Co. • •••••••••••••••• 185 Doeskin Products Co. • ..••.•••.••.••...•..•.••.•.•• 185
1Z 13 ILLUSTRATIONSz ILLUSTRATIONS--Continued.
Plate 1. Photograph of a typical gaging station on Red Figure 13. Relation of mean annual flood flow to drainage Clay Creek at Wooddale, Del. • ••••••••••• In pocket area •....•.•.•...... ••....•...... 65 Z. Map of the culture of northern Delaware " 14. Extremes of observed water temperatures by 3. Generalized geologic map of northern Del- months for Red Clay Creek at Wooddale ••• 71 aware .•••••••••••..•.•..•••.••...... •••• " 15. Diagram of the occurrence of ground water and 4. Geologic cross section ofthe Coastal Plain soil water .•.•••.•...... 78 of north ern Delaware taken approximately 16. Diagram contrasting porosity and permeability 79 downdip from Newark to Delaware City " 17. Drawdown cones in the vicinity of a pumped well 5. Configuration of the basement crystalline near Delaware City, illustrating the coeffi rock beneath the Coastal Plain of north- cients of transmissibility and storage de ern Delaware. .••....•••••.. .• ...... •••• " rived from the Theis formula ••••••••••••• 81 6. Composite log of a deep test hole at New 18. Index map of northern Delaware showing the let Castle, Del .••...••.•••....•..•...... •... " tered 5-minute grid used to number wells, 7. Geologic cross section of the outcrop of Cre and showing the observation wells in the area 83 taceous rocks and Pleistocene deposits 19. Diagram of a pumped well in sand and gravel, along the Chesapeake and Delaware Ca- showing the coarse material which envelops nal ••.•••••.•••..•••..•.••.•.•••.••..••.• " the screen after well development •••••••• 85 8. Configuration of the base of the Pleistocene ZOo Graph of water levels in five observation wells series in northern Delaware ...•....•...••• " in northern Delaware, and precipitation and temperature at New Castle County Airport, 1950 to 1955.•.....•...... •...• 91 Figure 1. Block diagram of the geomorphic provinces of the Zl. Geologic cross section of the crystalline rocks Central Appalachians and the Atlantic Coastal in the Piedmont of northern Delaware, from Plai~,indicating the northern Delaware area. Zl the Great Circle to Newark, and the edge of Z. The hydrologic cycle •.••.•••••••••.•••••.•••• Z8 the Coastal Plain .•..•...... •...... ••• 96 3. Bar graph showing length 9f gaging-station rec- ZZ. Schematic cross section through overburden in ords .•..•.•••••••.•••..•.•••...... ••••• 37 gabbro area, showing development, along 4. ~cationmap showing outlines of drainage basins lines of sheeting and jointing, of boulders above numbered sites (see table Z for descrip- in clayey matrix .....•..•...•.••.•...... 108 tion) ••••.••.•••••••••.•.••••.••••••••••• 38 Z3. Monthly average specific conductance of Brandy 5. Summary of monthly discharges for Brandywine wine Creek at Wilmington, December 1946 Creek at Wilmington •.••.....•.•.•••••••. 44 to September 1950, and computed average 6. Flow-duration curves for White Clay Creek near dis solved solids .•..•...•...... 143 Newark •••••••••••••••••••.•••••••.•••• 46 Z4. Conductance - duration cur v e 0 f Brandywine 7. Flow-duration curves for gaged streams •••••• 49 Creek at Wilmington, 1947 to 1949•••••••• 145 8. Low - flow frequency curves for White Clay and Z5. Conductance-rating curve, a plot of specific con Brandywine Creeks ••.••.••••.••••••••••• 51 ductance vs , discharge of Brandywine Creek 9. Frequency of maximum period of deficient dis at Wilmington, 1947 to 1949•••••••••••••• 147 charge for Christina River at Coochs Bridge. 56 Z6. Flow-duration curve for the Delaware River at 10. Frequency - mass curve and storage-draft lines Trenton, N. J••••••••••••••••••••••••••• 151 for Christina River at Coochs Bridge •••••• 59 Z7. Graph of specific conductance of water in the 11. Allowable draft - frequency curve of storage re Chesapeake and Delaware Canal, November qutzed on Christina Rive r at Coochs Bridge • 60 1955 to July 1956 ••••••••••••••••••••••• 155 lZ. Relation of ratio of mean annual flood versus fre quency at four stream-gaging stations ••••• 64
14 15 TABLES TABLES--Continued.
Table 1. Tests commonly made for water analysis ••••••• 33 Z4. Spe eif ic conductance and chloride content in water Z. Drainage areas of streams . 40 in the Chesapeake and Delaware Canal at Sum 3. Summary of monthly and yearly discharge during mit Bridge pier, November 1955 to April 1956 157 period of record ..•••••...... •...•••••. 4Z Z5. Chemical analyses by the U. S. Geological Survey 4. Duration of daily-flow at stream-gaging stations 48 of ground water in northern Delaware ••••••• 160 5. Low-flow frequency at stream-gaging stations ••• 5Z Z6. Chemical analyses by commercial laboratories 6. Results of low-flow discharge measurements made of ground water in northern Del aware •• 164 at sites other than stream-gaging stations ••• 54 Z7. Selected analyses of water from wells at Hercules 7. Annual low-flow frequency for days of deficient Experiment Station in the Red Clay Creek val- discharge at stream-gaging stations •••••••• 57 ley ...... •..••...... 167 8. Storage-required frequency at stream-gaging sta- Z8. Periodic analyses of chloride content in wells at tions ...•.....•...•...... •...... •...•.. in po cket Atlas Point, Del. . . 169 9. Annual flood peaks on Brandywine Creek at Chadds Z9. Chloride in water from shallow gallery wells Ford, Pa . 6Z Cd5Z -1, -Z,- 3, and-lO at New Castle, Del •••• 170 10. Estimated average discharge for the larger drain 30. Average daily production or use of surface water age basins of the Coastal Plain ••.•••••••••• 76 in northern Delaware in 1955, by source •••• 17Z 11. Age distribution of wells in northern Delaware, by 31. Average daily production or use of ground water type •...... ••.. , .• 86 in northern Delaware in 1955, by source .••• 174 3Z. Comparison of 1955use with existing and potential iz. Measurements of flow and temperature of four 0 springs in the Piedmont of northern Delaware 88 fresh surface-water supplies ••••••••••••••• 189 13. Characteristics of geologic formations in northern 33. Estimated recharge to aquifers in northern Dela Delaware ...••.••.•...... •..•.... 94 ware and portions recoverable by pumping of 14. Yields of wells in northern Delaware, by geologic wells •.•.••...••. eo ••••••••••••••••••••••• 193 source ...... •...... •...... •.••• 98 34. Storage-yield studies for stre-ams in area of north- 15. Specific capacities of wells in northern Delaware, ern Delaware .•.••.•..•...... •..•.•..•...• Z09 by geologic source . 99 35. Status of water suppliers in New Castle County •• ZlZ 36. Initial cost of developing various surface water 16. Average thickness ofthe weathered zone in crystal line rocks on the Piedmont and beneath the sources ...... ••...... •...... • Z16 Coastal Plain sediments ••.••••••••.•••••.• 101 lithology of the and 17. Comparative lower, middle upper aquifers in nonmarine Cretaceous sedi ments in northern Delaware .•..•..••••..•.. 113 Threshold values for iron in process and cooling 18. warers , •••••••••••••••••••••••••••••••••• 133 19. Limiting concentrations of dissolved solids for industrial waters...... 135 ZOo Maximum hardness for various industrial proc- esses •.••••••••••••.••.•••• 0.• • • •• • •• • • • • • 137 Zl. Chemical analyses of the streams in northern Dela- ware area on selected days. ••••••••••••••• 140 ZZ. Drainage areas and discharge rates of the main tributaries of the Delaware River between Trenton, N. J., and Marcus Hook, Pa...... 149 Z3. Monthly discharge of the Delaware River at Tren- ton, N. J., and Marcus Hook, Pa., October 1953 through September 1955...... 153 16 17 INTRODUCTION
By J. J. Groot, W. C. Rasmussen, and R. O. R. Martin
The Delaware River valley between Trenton, N. J. , and Delaware City, Del., has experienced rapid industrial expansion during the last few years, in large part because the Delaware River and some of its tributaries offer excellent opportunities for navigation and the development of water resources. It has been found that this develop ment creates many complex problems of a hydrologic and technical nature as well as an economic nature. Hydrologic problems are those concerned with quantity and quality of water, and technical problems are concerned with the techniques of making water avail able.
PURPOSE AND SCOPE OF THE INVESTIGATION
'In Delaware, that part of the Delaware valley comprlslng the northern half of New Castle County, referred to herelnas "northern Delaware, "has experienced acute needs for more water, and for water of quality as good or better than that obtained in the past. This report deals with the quantity of water in our streams and in our ground-water reservoirs, with the chemical quality of these bodies of water, and with their present and futur-e utilization.
Streams and ground-water reservoirs occur in nature without regard to political boundaries, and consequently the scope of many water -resources problems are interstate. Thus, although this re port is concerned with the water resources of northern Delaware, some consideration must be given to developments outside the St ate., notably to effects of additional withdrawals of water from the Dela ware River on the salinity of the river, and to the flow of Brandywine Creek, Red Clay Creek, and White Clay Creek, large segments of whose drainage basins are in Pennsylvania and Maryland.
It is of great practical importance, and in recent years has be come a matter of urgency, to know how much water can be made available for future development in northern Delaware. Such an evaluation constitutes a very complicated problem, and it must be realized that the conclusions drawn in this report are p rovi sfonal in that they depend on rutur e conditions, both natural and man-made, that are subject to change. The importance of physical limitations an the water resources may be outweighed by the cost limitations imposed by the ecqnomics of water supply. For these reasons the sections on potential development and the economics of water man agement are considered essential parts of this report.
19 DESCRIPTION OF THE AREA
Northern Delaware as considered in this report is the portion of New Castle County north of the Chesapeake and Delaware Canal. The area is about equally divided between the Piedmont and the -e Coastal Plain by the Fall Line, which passes through Newark. The GI ... GI": land area in New Castle County covered in the report is i41 square > ... miles. Surface drainage is generally eastward into the Delaware o 0 oQ. I) River except for a relatively small area in the southwest corner ... e which drains into Chesapeake Bay and several small streams which ....GI -II> empty into the Chesapeake and Delaware Canal and thence flow, ac . Topography and Drainage Small parts of two extensive physi«>graphic provinces, the Pied mont and the Coastal Plain, are represented in northern Delaware. The rolling hills of the Piedmont province are underlain by weath ered crystalline rocks; the relief--that is, the difference in altitude between the highest and lowest points--isabout 440 feet, which is also the maximum for northern Delaware as a whole. In the area occupied by the Wissahickon formation and the Cockeysville marble (see the geologic map, p1.3 ) the topography is characterized by well-rounded ridges whose crestlines, in any given locality, are of approximately the same altitude. In the area of the gabbroic rocks, however, the hilltops are broad, forming relatively flat areas which in part are covered by sedimentary material. In general, the hills are highest near the Pennsylvania State line, gradually descending to the south and east. The Coastal Plain, underlain by unconsolidated sedimentary rocks, is relatively flat. In the area north of the Chesapeake and Delaware Canal, the maximum relief is only 180 feet. The flatness of the Coastal Plain results in poor drainage in several places . .!.L Locations are shown on Plate 2. 20 21 NorthernDelaware is drained principally by the Christina River, of the Quaternary s ys te m have been fo und, except for relatively the largest tributary of which is Brandywine Creek. In the area of thin deposits of sand and gravel of possible Pliocene age in srna.Il the Wis sahickon fo r mat ion , the s tr e am pattern has adapted itself upl and areas. The stratigraphy and lithology of the rocks of north to a considerable degree to structural features of the rocks. The ern Delaware are discussed in SOITle detail in the section on ground rno st p r orrrine nt feature of the at r e arn s in the Coastal Plain is their water, because these geologic factors dere rrnine the occurrence of tendency to flow app roxrm atel y along the strike of the s edrmenta.r y ground water and the characteristics of the aquifers. fo rrnati ons , as dernons t r ated by the lower portion of White Clay Creek and by the Christina River. CliITlate Regional Geology The quantity of fresh water available in any area depends, aITlong other things, on cl irriat ic .condit ioris , particularly on pre cipitation The Pf edmont of Delaware is a part of the Appalachian Mountain and t ernpe r-atuz-e , s ys t ern , underlain by tightly folded crystalline rocks of s edtm enta r y and igneous origin which are pr e surned to be of late P'r e carnb r-i an or The cl irnate of Delaware is clas sified by' Koeppen (Trewartha, early Paleozoic age. The m.eta s edi me nts are represented by the 1943, p, 518-520) as wa r m , ternpe r ate , and rainy, with a hot SUITl rocks of the Wissahickon fo r mati.on and the Cockeysville rna r hl e , rne r and no distinct dry season. The average annua.l precipitation and the igneous and rrieta-d.gne cu s rocks are represented by grano in northern Delaware is 44. 1 inches, the greatest monthl y average diorite, serpentine, and various gabbroic rocks. The lithology and being 5 Inch es in August, and the srrral.le s t a little less than 3 inches s tr uctur e of the rocks have a great influence on their water-bearing in February. The average annual t ernpe r atu r e in northern Delaware properties, on the drainage pattern establishedon thern, and on their is 55. lOF; the highest average monthly, te mp e ra tur-e , 76°F, occurs associated land fo r m s , in July, and the lowest average t emper atur e , 35 0F, in February. The s t r e arn s des cend in rapids or falls fr o m the hard crystalline In general, winters in Delaware are rnrl d, with few prolonged rocks of the Pd.edrno nt to the soft, unconsolidated s edrme nt s of the periods of freezing weather. Thus, freezing of soils, which pre Coastal Plain. The narrow zone in which this occurs is called the vents ground-water recharge, s el dorn OCCClrs. The war-m SUITlITlers Fall Zone. The regional geologic relationships are shown in the are characterized by high evaporation losses which, when coupled block di ag r arn , figure 1. with deficient precipitation, reduce the available water supply. Ex tensive droughts, however, are rare, and the cl.i ma te of northern The Coastal Plain of Delaware is ~derlainby a wedge-shaped Delaware generally can be regarded as favorable to the de ve loprne nt series of strata of sand, clay, and gravel, whose thin edge is at the of fresh-water supplies. Fall Line and which gradually thickens toward the southeast. These s e di rrient s are of Cretaceous and Tertiary age, and they were de Occasional droughts do occur, however, during the late SUITlITler posited on the subsiding eastern rn a r g in of the rocks of the Paedmont. and fall, when evapotranspiration is greatest, resulting in a te rn « The strike of the aedtrnenta r y rocks of the Coastal Plain is approx porary decline of the water table and reduced streamflow. Such Irnate ly northeast, and the dip is to the southeast at low angles. As droughts have induced rnany f'ar me r s to apply suppl ernerrtal irriga these deposits are beveled by an erosion surface, and etched into tion, at the ve r y tdrne that both ground and surface water are in short low relief, they crop out on the erosion surface in parallel bands, est supply for the year. the older strata being exposed near the Fall Zone and the succes sively younger strata at increasing distances fr orn that zone. In Population rno s t of northern Delaware the erosion surface, and thus the outcrop belts of the strata, are covered by a relatively thin blanket of sand and gravel of Quaternary age, and are not exposed except where The population of northern Delaware is increasing rapidly. The s t r e arn erosion has cut through the Quaternary deposits. increase in population and in the per capita cons umption of water are responsible for the creation of the water pr obferns which have Although thick sections of Tertiary deposits occur in the south stirred up great interest in New Castle County. ern part of Delaware, north of the Chesapeake and Delaware Canal only s ed irrierrts of the Cretaceous s y s tern and the Pleistocene series In 1950, 218,879 people, or about 69 percent of the total popu lation of the State, lived in New Castle County. Alrnos t half of thern I 23 j.i ..... lived in Wilmington. Since 1950, further increases have taken place; Water-supply developments must take into account problems of Whitman, Requardt and Associates (1956) estimate that the 1955 pop waste-water disposal.' A trunk sewage system has been developed ulation of northern Delaware (north of the Chesapeake and Delaware in northern New Castle County, and soon nearly all sewage will be Canal) is approximately 250,000, and maybe about double that num discharged via interceptors. The Delaware Board of Health and the ber by the year 2000. Consequently, greater use of the water re State Water Pollution Commission are largely responsible for the sources of northern Delaware is inevitable. effort to clean up the streams in northern Delaware, and the inter ested reader is referred to reports by Kaplovsky (1950, 1955). So PREVIOUS INVESTIGATIONS far relatively little is being done in northern Delaware to recondition and reuse waste waters. Previous investigations of the geology and ground - water re Problems of water conservation have been studied by the Brandy sources of Delaware, or parts of the State, are discussed in detail wine Valley Association and the Red Clay Valley Association. Pub by Groot and Rasmussen (1954), Groot, Organist, and Richards lications of these organizations are available at their headquarters (1954), Marine and Rasmussen (1955), and Groot (1955), and a new in Wilmington. review of the literature is considered unnecessary for the present report. The New Castle County Conservation District and the Chester County (Pa, ) Conservation District have been instrumental, with the Streamflow records for streams in this area are published an Soil Conservation Service, in reducing erosion in the drainage basins nually by the U. S. Geological Survey in water-supply papers called of the area and thereby reducing the turbidity of affected streams. "Surface water supply of the United States," (subsequent to 1950, M. G. Wolman, of the U. S. Geological Survey, has completed a Part 1 B). In addition, Hul.rne (1954) described the surface-water highly technical study of some of these factors on the Brandywine resources of the Newark area and made flow-du:r;ation studies of Creek basin (1955). White Clay Creek. He concluded that the water resources of this creek were developed only to a very limited extent in comparison The Extension Service of the U. S. Department of Agriculture and to the potential development. the School of Agriculture of the University of Delaware have prepared numerous administrative reports on land use, cropping, forestation, The broad aspects of water supply have b e'en considered by the and related activities which have an effect on the water supply of Delaware Water Resources Study Committee in a report entitled northern Delaware. The School of Engineering at the University "W-ater in Delaware" (Worrilow and others, 1955). Of particular has investigated the relationship between rainfall and runoff (Pearson interest is the section on the legal fahors affecting water supply. and Behn, 1956). The Public Service Commission of Delaware released a short re port (Mebus, 1955) on the distribution of water by the franchised PERSONNEL AND ACKNOWLEDGEMENTS water companies, with recommendations on some redistricting. The Levy Court of New Castle County published a comprehensive review of water supplies in the county, through its consultants, Whitman, The investigations described in this report were made coopera Requardt and Associates (1956). Particular emphasis was placed tively by the United States Geological Survey, the Delaware Geo on the lack of storage facilities, on the use of mass diagrams in logical Survey, and the University of Delaware. They were under stream analysis, and on comparison of water rates and other econ the general supervision of Carl G. Paulsen, Chief, Water Resources omic factors. Division, U. S. Geological Survey. The State cooperation was direc ted by Johan J. Groot, State Geologist, Delaware Geological Survey. The chemical characteristics of Delaware River water between Trenton, N. J. , and the Pennsylvania-Delaware State line have been The s u r fa c e-cwat e r investigations were made under the direction described by Durfor and Keighton (1954). Their study shows that the of J. V. Wells, Chief, Surface Water Branch, and under the imme river is reasonably fresh as it enters Delaware during most of the diate supervision of Floyd F. LeFever, District Engineer, U. S. autumn, winter, and spring, but somewhat salty and low in dis solved Geological Survey, assisted by Arthur E. Hulme and Robert O. R. oxygen during the summer and early autumn. Kaplovsky (1952) has Martin, Hydraulic Engineers, U. S. Geological Survey. studied the dis charge of iron-bearing wastes into the Delaware River, originating within the State of Delaware. The ground-water investigations were under the direction of A. N. Sayre, Chief, Ground Water Branch, and Henry C. Barksdale, 24 I 2.5 Staff Engineer, U. S. Geological Survey, and under the immediate SIGNIFICANCE AND SOURCES OF WATER supervision of William C. Rasmussen, District Geologist, U. S. Geological Survey, assisted by Richard F. Ward, Geologist, Del By W. C. Rasmussen, E. F. McCarren, and N. H. Beamer aware Geological Survey, and Catharina R. Groot, Geologist, and Durward H. Boggess and O. Jack Coskery, Engineering Aides, U. S. Geological Survey. Average annual precipitation in northern Delaware is abundant, average annual streamflow is plentiful, and ground water is avail Investigations of the quality of water were under the direction able in most places in moderate to large quantities, yet growing of S. K. Love, Chief, Quality of Water Branch, U. S. Geological population and industrialization bring the threat of water problems Survey, and under the immediate supervision of Norman H. Beamer, in the future unless plans for conservation and utilization of the District Chemist. Edward F. McCarren, Chemist, prepared sec area's water resources are made now, on the basis of adequate hy tions of this report, assisted by Charles N. Durfor, Chemical Engi drologic knowledge. neer. Although water resources are abundant in northern Delaware, The section on the Economics of Water Management was prepared they are strictly limited in certain areas. For example on part of by Vaughn C. Behn, Associate Professor of Civil Engineering, Uni the upland north of Wilmington, they are meager. The reasons for versity of Delaware. this situation are diverse and complex. The lack of storage facil ities to retain the surplus water during periods of high discharge Many persons generously furnished information or contributed and in seasons of low demand, however, is primarily responsible. otherwise to the success of the investigation. John R. Ennis, of Ennis Brothers, Odessa; Fred R. Kielkopf and Jerome N. Unruh, The lack of adequate storage for surface water and the uncon of the Middletown Well Drilling Co. ; Oliver C. Lewis, of the Layne trolled use of water by natural vegetation combine to cause a loss New York Co.; and James F, Schultes, of A. C. Schultes 8 Precipitation is the source of all recharge. Through overland runoff it raises the flow of streams and replenishes surface reser voirs. By infiltration in excess of the moisture demand of the soil zone, precipitation restoreS the ground-water levels, raises the water table, and increases artesian head. 27 26 When man diverts water to his own purposes he interrupts the water cycle at points of advantage. His diversion works, consisting of reservoirs, wells, treatment plants, pumping stations, and dis tribution systems, become a part of the cycle. After using the I' I I water, man eventually discharges it to the sea, frequently warmer and somewhat polluted, and with lower potential energy than when he took it. From ocean basins, the huge evaporation pans of the Ilj"I world, the water is purified by evaporation, and condensation form ing clouds, and returned to the earth through precipitation. I, Ir~ The equation for the water cycle, in simple terms, is I ~~ '!>I P = R + ET +~S ~~ O')~ in which P is precipitation R is runoff, surface and ground-water ET is evapotranspiration, the sum of evaporation oJ .... from soil and water surfaces, E; and evaporation u >. T u from plants, or transpiration, ...u tIG tJ.S is the change, f). , in storage, S. .s o .. The change in. storage, li S, is the main point at which man can 1., modify the values of the equation to his own advantage. By storing ~ water at the highest pos sible altitude, man can use its potential en I I ergy to turn water wheels or generators, and change potential to N kinetic or electric energy. He can also use the water for drinking, ., .. cooling, washing, or irrigating, in the manifold municipal, indus ~ ...tIG trial, and agricultural processes. Furthermore, by taking water tz. from storage in the ground, man can use the accumulated recharge of past ages, and in partially empty ing a ground-water r-e s e rvo i r he may enable it to receive recharge which it otherwise would have to reject. By irrigation he can increase the moisture in the soil zone, at times most beneficial to plants. All these methods of utilizing storage do not modify the basic equation much in its totality, for year in and year out the effect of storage become s very small and the equation in the long run is re .~.~ duced to P = R + ET Instead, manipulation of~S may change the relation of Rand ET, most often, perhaps, by increasing ET and decreasing R. 28 29 SOURCES OF WATER The seven aquifers of lesser importance are the upper aquifer of the nonmarine Cretaceous sediments, the Magothy fo rrna tion; the Fresh Surface Water Wenonah sand; the Red Bank sand (Groot, Organist, and Richards, 1954); the Bryn Mawr(?) gravel; the Wissahickon formation (com posed of schist), with an included fold of the Cockeysville marble, In the report area fresh surface water is plentiful in the Piedmont and their weathered products; and the intrusive crystalline rocks, province and adequate in the Coastal Plain, Brandywine Creek is the primarily gabb ro and granodiorite, with small sills and dikes of largest source of fresh water in the State and Red Clay Creek, White pegmatite, and their weathered equivalents. Clay Creek, and Christina River (above its junction with White Clay Creek) are fresh water sources of smaller importance. Mill (or Wells in these lesser aquifers may range in yield frorn large, in Army) Creek, Red Lion Creek, Dragon Run, Shellpot Creek, Naarnan the upper aquifer of the nonrna r ine Cretaceous sediments, to very Creek, Stoney Creek, and the remnants of St. Georges Creek in the small, in the gabbro. The overall sustained ground-water production Chesapeake and Delaware Canal area, are sources of minor signifi of each of the lesser aquife r s , however, ranges from moderate for cance. the sedimentary formations to meager for the crystalline rocks. The water ranges in quality from generally good to somewhat hard and Ground Water high in iron. In defining these ten reservoirs or sources of ground water it There are ten principal water-bearing formations, or aquifers, should be understood that nature has no sharpboundaries, and some in northern Delaware, defined on the basis of the local geology. It water is capable of seeping from one reservoir to another, even is believed that these ten sources are all that exist, inasmuch as ex though the rate is very slow. The confining clays, or aquicludes, ploration has proceeded to the point where the discovery of additional as they may be called, are not completely impermeable, but are sizable reservoirs is unlikely. This is not to say that the present slightly leaky. The Pleistocene series, as a whole, forms a mantl e reservoirs are completely understood, whether in regard to their over much of the Coastal Plain, and permits the flow of ground water areal extent, boundaries, intake belts, confining members, or in readily into, or out of, underlying permeable formations that are in ternal characteristics. Rather, it is to say that their general shape contact with it. In spite of this ground-water flow across reservoir and attitude, recharge, discharge, storage, and transmissibility boundaries, the ground-water reservoirs can be defined by drilling, have been "roughed out, "as it were, and the considerable task which and the reservoir walls do form distinct hydraulic boundaries which remains is to determine the details. are recognized in controlled tests on large-capacity well fields . • Three of the ten sources are of major importance--that is, each Saline Water is capable of sustained yields of several million gallons a day of water of good to excellent quality. These are the Pleistocene series and the lower and middle aquifers of the nonmarine Cretaceous sedi The saline-water reserve available in northern Delaware is very ments. All three of these major sources are o fva "channel" type, large, as it consists of the Delaware River, the tidal portion of instead of a "sheet" type -- that is, they consist of interbranching the Christina River, short segments of minor tributaries to both of and to some extent of crisscrossing, or interlacing, channels filled these rivers, and the Chesapeake and Delaware Canal. Thus, half with fine to coarse sand and gravel, separated by interchannel bodies the periphery of the northern Delaware area is formed by saline of silt and clay. This peculiarity is due to their probable origin as water sources. In 1955 these s al i ne-swate r sources were providing river deposits, consisting of banks of river sand and silt separated about 80 percent of all the water used in northern Delaware. Most by flood-plain clays and swamp detritus, and possibly by lake or of this use was for low-quality, high-volume purposes, such as cool lagoon material. ing water in the generation of electricity and cooling and wash water for several industries, such as chemical works, oil refineries, and The buried channels of Pleistocene age have been partially de paint factories. fined for the first time in this report, on the basis of logs from several hundred wells. The channels of the nonmarine Cretaceous Salt-water intrusion in the lower Delaware River has long been sediments are only indistinctly known because geological control a situation of serious concern to industries and municipalities lo has not advanced to the point of interpretation, except at afew local cated along its shores that depend on the river as a source of fresh aile; of intense well density and accurate log information. water. Saline intrusion is especially evident south of the Delaware 30 31 Memorial Bridge. The concentration of most ions increases in the Table 1. --Tests commonly reported for water analyses. downstream direction, because of the mixing of brackish water with fresh water. Where the water contains more than 250 ppm of chlo ride, it is usually slightly saltier near the bottom of the river than Test A. B. C. D. at the top. There is a tendency for the saltier water to move up and down river along the bottom, owing to the difference in density be 1. Bacteriological examinations tween fresh and salt water, the saltier wateralways being on the 2. Organic nitrogen -- bottom. 3. Albuminoid nitrogen 4. Ammonia nitrogen Although "salt-water movement in an estuaryis dependent on many 5. Nitrite ----- variables and is complex, the general conditions can be described as 6. Taste and odor - follows: 7. B. O. D. ------8. Dissolved oxygen ----- The salinity of water at any given location varies through the day 9. Oxygen consumed ----- because of the tides. On the flood tide, water flows from the ocean 10. Turbidity --- - into the estuary and the flow of water in the river is upstream. On 11. Manganese -- - -- the ebb tide the water level falls and water flows seaward in the river. 12. Iron ------Between the flood and ebb tides there is a period, referred to as the 13. Fluoride ----- high-:water slack, when the water flows neither upstream nor down. 14. Color - Similarly, between the ebb and flood tides, there is a period, called 15. pH the low-water slack, when the water has no upstream nor downstream 16. Nitrate ----- movement. There are two high-water slacks and two low-water 17. Chloride ------slacks in each lunar day of 2.4 hours and 50 minutes. 18. Alkalinity or acidity - 19. Dissolved solids ------Highest concentrations of chloride occur usually at high-water 20. Hardness ------slack and lowest concentrations at low-water slack. The two maxima 21. Sulfate ------for the htgb -wate r slacks of any given lunar day are relatively close 22.. Magnesium ------in value, but this value will vary from day to day in accordance with 23. Calcium -- ,--- - conditions of tide and flow. The sam; is true for the minimum con 24. Specific conductance- centrations of chloride. As fresh water flows downstream on an 2.5. Sodium------ebb tide the chloride at all locations .decreases and does so until the 26. Potas sium - flood tide begins. Saline water is diluted and pushed back from the 27. Silica ----- river by the fresh-water discharge. The flushing action continues 28. Boron -- - -- ~ ----- until the low-water slack, at which time the following flood tide car ries salt water upstream. The flood tide will end at the high-water slack and give way to the reverse process as the ebb tide begins. Tests for determining sanitary quality of potable or polluted waters. SIGNIFICANCE OF WATER QUALITY B. Tests for determiDing suitability of water for industrial uses. Quality-of-water studies are concerned in large part with varia C. Tests for determining suitability of water for agricultural uses. tions in kind and concentration of chemical substances dissolved in water, and the reasons for the variations. The quality-of-water data D. Tests for determining geological relations of natural surface may be used to determine the suitability of water for various uses; and ground waters. for estimating the effects of use or diversion of water on the quality as a whole; and the effects ofenvironmental factors on water quality. The tests commonly made to determine the suitability of water for various uses are given in table 1. 33 az Because a high percentage of surface water is used by industry SURFACE WATER for cooling purposes, the water temperature becomes an important factor in the location of industrial plants, their economical oper By R. O. R. Martin and A. E. Hulme ation, and their methods of processing material. Records of river temperatures show that wide s eaaonal variations occur, and that temperatures may differ with depth of water. Generally, the lower A substantially large quantity of fresh surface water drains from the temperature of surface water in summer, the more desirable it the Piedmont province through northern Delaware. Most of this is as a cooling agent. Some industries use surface water in the win water comes from the Pennsylvania portion of the drainage basin, ter and ground water in the summer, taking advantage of the fact that because only about 25 percent of the total drainage basin lies in Del the temperature of ground water shows little seasonal variation and aware and less than 2 percent is in Maryland. The streams draining is much cooler than surface water in the summer. The temperature from the Piedmont province are the present and the principal future 0 0F, of shallow ground water in Delaware averages about 56 to 57 source of surface water for northern Delaware. approximating the mean air temperature of 55. 10F. The fresh surface water in streams of the Coastal Plain ori The quality of water required varies according to the process in ginates in Delaware. The flow from 10.7 square miles of Coastal which the water is used. For example, soft water is required for Plain area drains into Maryland. For the most part, not much use steam generation and for laundering. The extent of treatment or the is made of this water because of the small flow from small drainage suitability of water for use can usually be determined from water basins, their great distance from point of potential use, and the salt analyses. Waste water from industrial processes, if allowed to water encroaclunent in the tidal reaches of these streams. Surface enter streams without treatment, often affects the quality of the water in the Coastal Plain probably will be most useful as a source stream water for industries downstream. Municipal water supplies of artificial ground-water recharge. almost always receive some treatment before use. The specifica tions of water quality for drinking and cooling on interstate carriers The Delaware River is saline along the entire eastern boundary are stated by the U. S. Public Health Service (1946); many State of Delaware, so this water can be used only for certain industrial health departments have adopted these standards. uses and is not at present economically adaptable as a fresh-water source for municipal use. Water for irrigation must meet certain quality requirements, especially with respect to dissolved solids, percent sodium, and GENERAL PRINCIPLES boron concentration. From water-q~alitydata and a knowledge of soil characteristics and drainage and irrigation practice, a soil chemist can determine the suitability of water for irrigating specific The principles of measuring surface-water flow have been de crops. Water or poor quality may injure plant tissues, affect the scribed in many publications during the past half century. Stream permeability of the soil to moisture and air, or interfere with crop gaging methods and practices of the U. S. Geological Survey are de nutrition. scribed in Water-Supply Paper 888byCorbett and others (1943), and the methods of computing daily discharge are described in "Stream . Oyster culture and commercial fishing are important industries Flow"byGrover and Harrington (1943). The general procedure fol of the lower Delaware River. The most favorable salt concentration lowed at gaging stations in nor'thern Delaware is described in these for the maturing oyster and larvae lies between 14, 800 ppm and publications. From the gaging-station records the instantaneous or 30,000 ppm; salinities below 9,500 ppm can be tolerated for only average flow for any desired time can be computed. brief periods (Lunz, 1938). Shellfish beds require a permanent firm bottom which must be safeguarded against sediment and oily sludge. Definition of Terms The source and significance of the constituents most frequently determined is dis cus sed in the se ction on principles of water quality, Some of the terms of streamflow and other hydrologic data, as page 127. used in this report are defined as follows: Drainage area. --The size of the area drained by a stream above a given location, usually expressed in square miles (sq rni). 35 34 Discharge. --As applied to a stream, the rate of flow or the volume of water flowing in a given stream at a given place and within a given period of time. Stream discharge is usually expressed as an average flow for tpe period. One cubic foot per second flow ing for one day equals 86,400 cubic feet or 0.046317 million gallons. - Cubic feet per second (ds). -- The rate of discharge of a stream ~--'#- ~ whose channel is 1 square foot in cross-sectional area andwhose average velocity is 1 foot per second. 1931 Cubic feet per secondper square mile (dsm). --An average number u 1933 of cubic feet of water flowing per second from each square mile of area drained, assuming that the runoff is distributed uniforml y 1935 in time and area. 1937 Million gallon perdayper square mile (mgdsm). --An average num ber of millions of gallons of water flowing per day per square 1939 mile of area drained, assuming that the runoff is distributed u 1941 niformly in time and area. One mgd equals 1. 5472 cf s , ::'943 'c5 Runoff in inches. -- The depth to which an area would be covered if all the water draining from it in a given period were uniformly 194.5 distributed on its surface. The term is used for comparing run 1947 off with rainfall. Water year. --A 12-month period beginning October 1 and ending the 1949 following September 30. Designated as the year ending Septem 1951 ber 30. 1953 Climatic year. -- As used in this report, especially for low-water studies, the 12-month period beginning April 1 and ending the following March 31. Designated as the year beginning April 1. Combined surface and ground water yield. --The quantity of water, both surface and ground, availabte for use on a continuing basis from a drainage basin, expressed in cfs, mgd, or in cfsm, or mgdsm. Records Available The major river basins in the report area drain into the Dela ware River estuary from or through northern Delaware. These basins are discussed later in downstream order with complete de scriptions of the gaging stations within each basin. The report area contains o gaging stations operated by the U. S. Geological Survey in cooperation with the State of Delaware, New Castle County, and the City of Newark. The gaging station on Brandywine Creek at Chadds Ford, Pa ., just outside the report area is included in the analyses because its long-term record represents the flow from 97 percent of the Brandywine Creek drainage area at the Pennsylvania Delaware state line. Records for six other nearby gaging stations outside of the report area and one discontinued within the area are considered pertinent to this study. 37 36 The length of record available for each gaging station is indica ted on the bar graph in figure 3 and their index nwnber is plotted on the drainage-basin outline map in figure 4. The drainage areas of the principal tributaries within each major basin at pertinent points are listed in table Z with an areal breakdown by states for all streams that cross the eastern and northern Delaware state boundaries and flow into the report area. A typical gaging station, Red Clay Creek at Wooddale, Del. is shown on plate 1. Streamflow records in northern Delaware cover only a short period (see fig. 3). Most of the data have been collected since 1943 at 6 gaging stations on streams tributary to Christina River. An importantfact is that neither the extreme droughts of the earlythir ties nor the major floods of 1937 occurred within the period of record of these northern Delaware gaging stations. The drought of 1954 ranks only about fifth in ascending order of magnitude for the period 1896 to 1955. Some extrapolation of the short-term records can be obtained by detailed comparisons with records from long-term sta- . tions in adjacent states. All 6 gaging stations are close to the Fall Line; hence, the phys« iographyof the six gaged basins are es sentially that of the Piedmont region. Streamflow records in this report, therefore, represent the Piedmont only, and do not necessarily reflect the runoff from the Coastal Plain. Daily discharge records for gaging stations in and around north ern Delaware are published in U. S. Geological Survey water-supply papers as Part 1 and, subsequent to 1950, as Part lB of the Series of Surface Water Supply of the United States. Table 3 gives a sum> mary of monthly and yearly discharge during the periods of record, and indicat.es the year of each maximwn and minimum. The data for Brandywine Creek at Wilmington listed in table 3 is present"ed graphically in figure 5. Owing to their short duration ( see bar graph on fig. 3), the stream-flow records in northern Delaware contain rather limited . data in themselves but may be made more useful by correlation with longer records. Any complete analysis of streamflow data should include three principal objectives, namely, (1) to determine Figure ". -_Location map sbowing ouUines of dra.inage b.,in, above numbered Bitee [ee e tableZ (or de8cription). the flood characteristics which concern that portion of the stream flow regimen producing destruction, (Z) to determine the low-flow characteristics of the natural flow and(3) for economic reasons, to determine the storage req¢red to provide aflow In excess of natural low-flow. 39 38 tI> Table 2.--Drainage areas of streams in northern Delaware. o No. Drainage areas in square miles on ,Streams flowing through northern Tributary to: Basin In In In map New Castle County total Delaware Maryland Pa. DELAHARE RIVER BASIN 1. South Branch Naaman Creek at Arden . Delaware River a3.83 2.87 0.96 2. Naaman Creek at mouth Delaware River 13.7 6.50 7.19 2a Stoney Creek at mouth (at bridge on Gov. Frintz Blvd) Delaware River 2.37 2.37 3. Christina River at Coochs Bridge Delaware River b20.5 10.4 7.63 2.47 4. Christina River above White Clay Creek Delaware River 5Ll·. 2 43.9 7.85 2.47 5. ~fuite Clay Creek at Pa.-De1. line Christina River 62.4 1.2 61.2 6. vfl1ite Clay Creek above (upstre~ from) Newark Christina River b6G.7 5.51 .03 61.2 7. Wh~te Clay Creek at Newark Christina River 70.5 9.27 .03 61.2 n L~.13 U. Hidd1e Run at mouth vlhite Clay Creek 4.13 9. rike Creek at mouth vfl1ite Clay Creek 6.61 6.61 10. vfl1ite Clay Creek near (dm~stream from) Newark Christina River bB7.0 26.6 .03 61.2 11. Ni11 Creek at Stanton "illite Clay Creek a])12. l l· 11.9 .45 12. Hill Creel<: at mouth IfJhite Clay Creek 13 .2 12.7 .45 13. White Clay Creek above Red Clay Creek Christina River 10L~ 42.1 .03 61.6 14. Red Clay Creek at Pa.-De1. line lfhite Clay Creek 23.3 .15 28.1 15. Edgar Hoopes Reservoir Red Clay Creek 2.0 2.0 16. Red Clay Creek at Hoodda1e Hhite Clay Creek b47.0 13.7 33.3 17. Hyde Run at Brandywine Springs Red Clay Creek 2.3Q 2.33 ~i·>,. 18. Red Clay Creek at mouth . White Clay Creek 54.0 20.7 33.3 19. White Clay Creek at mouth Christina River 162· 67.1 .03 94.9 20. Christina River below White Clay Creek Delaware River 216 111 7.83 97.4 21. Christina River above Brandywine Creek Delaware River 238 133 7.88 97.4 22. Brandywine Creek (Henry Clay Bridge) at Wilmington Christina River b314. 17.0 297 23. She11pot Creek (Sellers Park) at Wilmington 'Del. f\ -Br&fuiyuifl:e Creek b7.46 7.46 24. She11pot Creek at mouth -:V~1, F~B_aRe""it'le Greek, 9.54 9.54 25. B~andywine Creek at mouth Christina River ~'3Iq ~22.o 297 26. Christina River at mouth Delaware River -568.5"5'8 lQ6- t5t. 7.83 394 27. Mill Creek (New Castle railroad bridge) near mouth Delaware River 6.39 6.39 28. Red Lion Creek at Red Lion (hwy. 7 bridge) Delaware River a3.20 3.20 29. Red Lion Creek (downstream railroad bridge) near mouth Delaware River 9.28 9.23 30. Dragon Creek (downstream railroad bridge) near mouth Delaware River 3.JO £.80 CHESAPEAKE ~ DELAWARE CANAL 31. Lums Millpond outlet at mouth . Chesa.& Del. Canal 4.36 4.36 32. Guthrie Branch at mouth Chesa.& Del. Canal 2.74 2.74 33. Long Branch at Md.-Del. line Back Creek 3.69 Long Branch at mouth (in Md.) Back Creek 8.12 3.69 4.43 CHESAPEAKE BAY 34. Perch Creek at Md.-Del. line Elk River 2.00 Perch Creek at mouth (in Md.) Elk River 8.25 2.00 6.25 a Site of 1955-56 low-water discharge measurements by U.S.G.S. e b Site of cooperative gaging station maintained by U.S.G.S. ~ Table 3.--Summary of monthly and yearly discharge during period of record. No. Mean on discharge fig. 4 in mgd Oct. Nov. Dec. Ja,n. Feb. Mar. Apr. May June July Aug. Sept. Water year Mean monthly discharge in million gallons per day 23 1.36 6.38 7.69 8.98 9.50 11.5 8.14 9.11 4.76 3.70 3.41 1.54 6.31 22 113 253 . 307 361 416 467 398 385 286 205 248 162 308 16 19.9 33.3 42.0 54.4 58.6 61.5 50.1 52.3 39.7 33.2 33.6 21.5 41.7 10 36.1 63.9 65.9 94.4 97.6 111 93.7 82.7 60.8 59.3· 59.2 44.5 74.3 6 23.3 41.6 55.7 62.2 60.2 91.8 78.9 67.2 49.9 32.4 52.2 27.8 48.9 3 5.45 15.0 19.1 22.9 25.3 28.1 20.0 22.4 12.9 13.8 12.1 6.59 16.9 Maximum monthly and maximum yearly discharge in million gallons per day 23 2.86 17.8 15.9 17.7 15.4 18.0 14.5 20.4 12.7 15.4 14.7 4.32 10.0 22 186 413 450 630 676 756 701 645 468 370 928 300 438 16 26.4 57.3 77.6 122 125 104 93.7 93.7 74.3 77.6 116 43.2 61.0 10 54.0 120 130 242 189 204 164 148 116 131 189 129 106 6 27.3 59.1 73.7 124 91.8 128 118 112 73.0 64.3 118 44.6 72.4 3 8.40 24.4 35.0 47.7 41.0 44.9 37.6 45.2 25.5 47.3 58.0 20.4 25.2 Minimum monthly and minimum yearly discharge in million gallons per day 23 0.53 1.03 2.79 1.16 3.20 8.27 3.35 1.14 0.78 0.45 0.83 0.58 3.92 22 64.6 101 148 112 145 300 214 128 113 66.6 91.1 67.2 163 16 10.2 16.5 18.6 15.0 24.2 32.6 23.6 15.6 15.8 8.66 12.0 9.95 26.3 10 22.7 26.6 26.8 28.4 33.9 66.6 43.5 27.3 27.9 15.4 18.5 9.69 48.9 6 17.5 27.8 31.0 22.9 32.7 55.9 33.2 20.2 22.7 11.3 19.3 15.0 36.4 3 2.80 4.57 6.85 5.64 6.53 15.3 10.4 5.42 3.96 2.36 2.79 2.24 10.7 No. on Water fig.4 Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June· July Aug. Sept. year Calendar year (last 2 digits) of maximum of record 23 50 47 51 49 48 52 52 47 46 52 55 50 52 22 50 50 51 53 49 53 52 52 52 52 55 48 52 16 50 50 51 49 48 53 53 48 48 45 55 45 52 10 45 35 51 36 36 36 33 52 46 35 33 35 52 6 53 52 52 53 53 53 52 52 53 52 55 52 53 3 43 50 45 53 51 53 52 47 46 45 55 45 52 Calendar year (last 2 digits) of minimum of record 23 52 49 47 55 47 47 55 55 54 54 51 51 54 22 54 49 54 55 54 54 55 55 54 54 54 54 54 16 54 46 46 55 54 47 55 55 54 55 44 43 54 10 54 49 31 55 34 47 55 55 54 55 32 32 54 6 54 54 54 55 54 55 55 55 54 55 54 54 54 3 54 46 46 55 47 45 50 55 54 54 54 54 54 II> w FLOW CHARACTERISTICS ..... The variability of streamflow creates problems of too little water .... o 8 g g 8 g 888 8 at times and too much water at other times. Thus, an analysis of Di8charge in Million Gallon. per D8T stream-flow characteristics logically falls into two parts--the anal ysis of. low flows and the analysis of flood flows'. Surface-water records are compiled and published by the Federal ttl ;p government on basis of the water year ending September 30. The (1) 0- I-' 0 water year makes a suitable period for analysis of flood flows but 0 < :t: (1) for low-flow studies a climatic year starting April 1 is preferable. III III Such a year keeps the seasonal low-water period during the autumn < < t"' (1) (1) (1) months continuous and permits statistical analysis of annual low til '":l '":l O'l OCT. 0 III III (1) flows. O'l O'l ~ ::s (1) I (1) Po Low Flows I: ,..•.•.. ",;'1<\\ \\ \~~I 54Ii.-.::;::f:·.:;":}(,l\.\\ \\...,1"1 The demand for surface water in northern Delaware during crit ically dryperiods requires low-flow frequency studies bywhich the relative effect of the known droughts can be studied. Particularly important is the outstanding drought of the early thirties, as this :;:':-.~:',:,::,,:·.:·.::-'::::~i.:.1\ 41~';::' \.\\ \.\.\.\.\ ' \.x).;,./. prolonged drought was one of the most severe on record in Delaware 5~L·.. ··" .. 1".," ••••••• :.t\'\'\\.\.\\.\.\.\. \.\.~ (and Maryland). Although none of the 6 gaging stations in the report area operated throughout this major drought, low-flow studies, pre pared for a report on the water resources of the Baltimore, Maryland area, provide data for transposing long-term stream-flow character istics into northern Delaware. Gaging-station records on Monocacy River near Frederick, Md., and Potomac River at Point of Rocks, Md., each 57 years ( April 1896 to March 1953 ) in length, provide a long-term base for this study. Records of such length show the variations in streamflow for the critical low - flow periods during the 34 years prior to the major drought of the early thirties as well as during that drought. In making analyses for this report the continuous streamflow r-e co r d of nearly 4Z years (August 1911 to December 1953) for Brandywine AW. 54 :~;ti~;l-}~3.\\\\\\\\\\\.\.\.\\\0~\\,,\~\~\\\\55J Creek at Chadds Ford, pa., was used also. Because of its prox I imity to northern Delaware and its complete coverage of the drought of the early thirties, this record, which represents about 91 percent of the flow at the gaging stationdownstream on Brandywine Creek at Wihnington, Dal., , serves as a valuable supplemental record for correlation purposes. The advantage of using the longer 57 - year ....o N g \J\ records is revealed, however, by the occurrence of a comparable o o 8 o 8 if not even more severe drought during September and October 1910 just prior to the establishment of the Chadds Ford gage. The "lowest flow on record" often is considered the "safe yield" 44 45 in water-supply design, particularly in the design of a small plant that is to take water directly from a stream with little or no storage being provided. The lowest flow on record depends upon the length of record and local variations in climatic and geologic conditions affect the occurre;nce of this lowest flow to such an extent that it is not feasible to make reliable estimates of the lowest flow during DISCHARGEIN MILLION GALLONS PER DAY PER SQUARE MILE some particular period outside the period of record. Thus, it be .... N Col ...... ODO comes apparent that low-flow studies should involve the frequency ~ of occurrence of the low-flows bybasing them on adequate long-term p streamflow records. lil e Flow-Duration Curves p N P ... Aflow-duration curve (see fig. 6) showing the percentage of time ::! 7 a a , .~ that specified discharge has been equaled or exceeded during ':!! ." - ~ ,/, Y .. ]l givenperiodis a convenient way to summarize streamflow frequency o'" N r Z data. In a strict sense the flow-duration curve applies only to the I '" ~~;~ I .... IJV period for which data were used to develop the curve. However, if ~ lil ... 1Ii the period on which the flow-duration curve is based, represents I .... ltV flow of the the be a ~ i long-term stream, curve may considered prob ~ '" :; ability curve and used to estimate the probability of occurrence of a i !2 It III specified discharge. Duration curves also provide ameans of study 2 0 ~ z ,I ing streamflow characteristics of a stream and of comparing one » l!l < ~f ... ~ , stream with another. 0' '" Col ~ 0 0 '"c: The duration curves of daily flow for 6 gaging station records in ~ ..~ ~e report area have been adjusted from their individual short-term ~ II. 0 g records to the 57-year (April 1896 to March 1953) base period and 0]l If I I !il ~ are presented in table 4. The relationship of the 5 major basins to -=0 H ~ s I ~ .. .'"x , • >-3 each other, based on the 5 principal gaging station records, is shown , J :z: l>l .. 0 ." ." ..... tll ~ o 7 0 !:l !:l l>l t"' in figure where daily-flow duration for the common 57-year base ..It'" '"0 H ~ H '" 0 0 0 ::: period is plotted in mgd per sq mi. r: 0 0 0 0 '" ffl o :z: l!l 0 ~ ...... ~ "l ~ > z II ~ ~ en (J) U1 &i H The difference between the curves plotted on figure 6 emphasizes .... Q (J) i 0 .... :z: J III ii I t:l t:l !2 1:l the importance o£ using a concurrent period when comparing stream Z ~ > t:l 0 ;" o 0 !ii !ii flow of two White ~ ill !ii !ii characteristics or more streams. The data for z '" '" 1ii III! ;:- ;:- '" € ~ Clay Creek near Newark adjusted to the 57-year period have been lSl I to to ;:- .... (J) ~ '" plotted on figure 6 together with the 8 - year (April 1947 to March ...... to ~ II en . /1 III III I ~ 1955) and the 6-year (April 1947 to March 1953) curves based on N ... 1Il ~ ~ to ~ actual records. The markedodifference between the curves for the 1/, III ~ , I ~N due to the :s 6-year and 8-year periods is exceptionally low runoff that occurred during 1953 and 1954. Similarly, the effect of the drought ~ ... durl-J:lg the early thirties is apparent in the 57-year curve. A long record, such as for the 57-year period, is more dependable because ! the experience of many years averages short-term variations. 46 47 C Table l •• -_ Duration of daily flow at stream-gaging stations in nortbern Delaware. (Adjusted to 57-year period. 1096-1952, on basis of long-term Streami1m1 records iu adjacent states) Gaging She11pot Brandyvline Red Clay \'lhite Clay ~Jl1i te Clay Cl1ristiua station Creek at .Creek at Creek at Creek near Creek above River at \'1i1mington Hilmington Hooddale Ne'o1ark Newark Coocha Bridge !'lap no. 23 22 16 10 6 3 Drainage area 7.46 314 47.0 U7.13 66.7 20.5 aq mi *Percent of time cfa mgdsm da mgdsm cfs mgdsm cfa mgdsm cfs mgdsm cfs mgdsm 1 . 104 9.01 2.720 5.60 520 7.15 905 6.66 587 6.66 401 12.6 2 59.3 5.14 1.920 3.95 ~45 4.7l. 599 4.41 455 4.41 235 7.41 5 27.5 2.33 1,180 2.43 182 2.50 317 2.33 2l}0 2.33 95.5 3.01 10 15.2 1.32 825 1. 70 119 1.64 207 1.52 157 1.52 54.0 1. 70 20 7.60 .658 540 1.11 79.9 1.10 139 1.02 105 1.02 30.0 .946 30 5.35 .464 433 .391 65.1 .395 113 .832 J5.9 .332 22.4 .706 50 3.02 .262 304 .626 46.6 .641 131.0 .596 61.5 .596 14.2 .t+43 70 1.65 .143 211 .434 32.4 .446 56.4 .415 42.8 .415 8.6 .271 SO 1.2B .111 130 .371 27.1 .373 47.1 .347 35.8 .347 6.6 .20S 90 .84 .073 133 .234 20.1 .276 34.9 .257 . 26.5 .257 4.4 .139 95 .63 .055 116 .239 16.4 .226 28.5 .210 21.7 .210 3.3 .104 98 .46 .040 95.2 .196 12.9 .177 22.4 .165 17.0 .165 2.4 .076 99 .33 .033 34.2 .173 11.1 .153 19.4 .143 14.8 .143 1.9 .060 *Percent of time discharge equaled or exceeded that aho~• )"~..:'.....,,., ,._.~ ;.~:~~::;~ •.. - - " " "'561'9611 """'.01 """-Li ".Of__...... '" -_.._ >Of ...... __AGU"'! ...... NMOHS .LYH.L 03033:lX3 110 onm03 3!lIIlI'H:lSIO 311I11 iD .LN3:lI13d .. n6 &6 86 56 06 08 Ol 011 OIl Ot OE Ol: 01 5 ~ 1 5'0 ~'O 1'0 'CIDIlI3:d lIV3:A-LS NO (JEVII JI:il3:HO .LOd'l'l!llS NO ~ 3:WLL so .LN3:0H3:d 86 OllClllllOXli lIO =nll3: 3:11 O.L Oll.L03:dXll 3:11 XVii wsaoli OtO'O dO 1l0'l Low-flow frequency curves ( see fig. 8 ) overcomes a serious shortcoming which is inherent in duration curves, namely, the lack of information on the chronological sequence of flows. For example, DISCHARGE IN MILLION GALLONS PER DAY PER SQUARE MILE a duration curve does not indicate whether the lowest 30 days of N N • ..... OJ '" • record occurred in one rare drought year or as a few days nearly· o en '" (11 O'l ..... OJ co o en '" every year, but in a low-flow frequency curve consecutive days are treated as a unit. From the low-flow frequency curve we learn how often the average flow for various length periods might be expected ..~ I- f;; to be as low as a specified value. I-- , ~~~ bb':::O Figure 8 presents a family of low-flow frequency curves for I- >"'> periods of selected length and indicates how often on the average I- ...... sc OJ ...... OJ I-- OJ ... OJ CD the yearly minimum flow for these length periods can be expected "''''0... '" '"0 0 MINIMUM 0 0 0 '" '" 0 ... '" '" '" 0 I-- iii en:> tl '"tl '"Z '" PERIODS '" '" '" tl tl .., § tltl tl tl tl tl Z to fall as low as any specified discharge. The discharge (in mgdsm), ~ »> > > > » > > > '" ...... ;( ~ Of is plotted as the ordinate with the recurrence interval (in years), as '" '" I the abscissa. For design use, the range in length of period of min ~ dl ~tiJ~ II II 1 imum flow from 7 -day to I-year periods permits the engineer a wide 00'" VIIII1/ Ii I 1// - •• H I selection of time periods of the average flow for different recurrence ~ ' II "''''"'... t/ 1/ I / I '/ 1/1/ I II intervals. For example, figure 8 indicates that at intervals of 20 f- II ~~~ 11 1/ years, on the average, the annual minimum 7-dayflow on White Clay 111 / / ;III / /1/ I 1/ f- ~~~ Creek near Newark may be expected to fall as low as O. 125 mgdper iT 1/ £>£>... rTI1 / II II II 1/ sq mi, or that a minimum 7 -day flow as low as O. 125 mgd per sq mi f- "'''' , 1 / j!lj!l\'? I II I II III 1/ II I I has a probability of one in twenty of occurring in any particular year. I-- ... --, ?Oi!j -, III I !I f- "':z: I-- 7 I I II II I 7 7 II I II II !I Table 5 gives low-flow frequency data for the 6 gaging stations f- ~~ 77 in the report ar ea and table 6 presents the results of 5 special low II ,I f- ~ II flow discharge measurements during 1955-56 at each of 3 sites other '" III! I I 1/ than gaging stations . .An estimate is shown for the annual minimum II I l I / daily discharge for a 2-year recurrence interval. Several of the~e I I I IIII I / II / I measurements include chemical sampling as indicated, the results IT 1 /7 rr 7 ill 1 / !/ / of which are presented in table 11 (p, 138) in the section on quali1¥ ~?z: 'I !il;i - II III / >tl III I / II 1/ of water. bl~~ ~a- »H ~~o ~~H~ I / I tl I'IIII1/ I >0 "''''\:g» ... - Days of Deficient Discharge fl !il[ll[:l I 1 _.~ >oo I I / II I .1""! Uf- !il~E- '"..., "'"> ~.~ - ...oo"'..,... l_ ~~[:i- :u> .. H'" s;OJ;;_ To show the nwnber of continuous days during which the dis .. jg!jj; gJC::~ charge remained equal to or less than a given discharge the data have :.il~[:i- oH~O.., , ::0>': - been analyzed in terms of maximum period of deficient discharge as g[:J~ tl ",:z:0 i shown in table 7 and figure 9. ~:, "'-H &il;J - car r "'F' Figure 9 for Christina River at Coochs Bridge, Delaware shows how often on the average the minimumflowfor selected lengthperi ods can be expected to remain below any specified discharge. This familyofcurves illustrates the use of data intable 7, which contains data for all 6 gaging stations in northern Delaware for recurrence 50 S1 IJl N Table 5.--Low-f1ow frequency at stream-gaging stations in northern Delaware. (Frequency of annual minimum discharge adjusted to 57-year period, 1896-1952, on basis of long- term streamflow records in adjacent states). Drainage Recurrence Average discharge (in mgd per sq mi) for length of minimum Gaging area interval period indicated in column headings station sq mi years I-day 7-day IS-day 30-day 60-day 120-day 183-day 9-month 12-month She11pot 7.46 2 0.057 0.065 0.073 0.088 0.114 0.158 0.218 0.330 0.509 Creek at 5 .034 .039 .042 .051 .064 .088 .126 .211 .338 Wilmington 10 .027 .030 .034 .040 .049 .066 .088 .158 .262 25 .020 .023 .026 .029 .037 .047 .062 .107 .182 50 .016 .018 .021 .024 .030 .037 .049 .082 .141 Brandywine 314 2 0.249 0.266 0.284 0.321 0.377 0.459 0.564 0.725 0.947 Creek at 5 .182 .194 .205 .231 .263 .321 .399 .550 .737 Wilmington 10 .157 .167 .177 .195 .224 .268 .321 .457 .622 25 .130 .139.. .150 .163 .187 .216 .257 .360 .500 50 .114 .122 .132 .144 .164 .189 .222 .305 .428 Red Clay 47.0 2 0.239 0.254 0.281 0.334 0.400 0.494 0.594 0.769 1.016 Creek at 5 .169 .179 .195 .228 .276 .344 .415 .551 .744 Woodda1e 10 .142 .150 .164 .190 .227 .278 .334 .448 .606 25 .122 .129 .139 .157 .184 .216 .253 .344 .474 50 .110 .116 .123 .138 .158 .182 .209 .285 .396 White Clay $7.8 2 0.218 0.236 0.261 0.311 0.372 0.459 0.553 0.715 0.950 Creek near 5 .153 .166 .182 .213 .257 .319 .387 .514 .693 Newark 10 .129 .140 .152 .177 .211 .258 .311 .418 .564 25 .111 .121 .129 .146 .172 .202 .236 .319 .441 50 .100 .108 .115 .128 .147 .169 .194 .266 .369 .'f"--,,.,. Christina 20.5 2 0.124 0.141 0.181 0'.235 0.310 0.400 0.571 River at 0.848 5 .076 .085 .107 .139 .187 .245 .363 .549 Coochs Bridge 10 .060 .067 .083 .106 .139 .181 .271 .410 25 .048 .053 .064 .079 .099 .124 .187 .293 50 .041 .045 .053 .064 .078 .094 .145 .229 Note: Figures for White Clay Creek above Newark are identical with White Clay Creek near Newan. I-day minimum flow for Christina River not determined due to flow regulation. ~ UI II.> intervals of 2, 5, 10, 25, and 50 years. The discharge by this meth od fora given recurrence interval is larger than that obtained by the average-discharge method for low-flow periods of the same length, because during part of each low-flow period the discharge is less than the upper limiting discharge. Storage-Required Frequency a co 0\ -:t 1lI .... ,-l .... The need for storage becomes apparent when the flow of a stream "0 C"I o o. o. o. in its natural state cannot meet the needs of a water-resources devel opment. The amount of storage required to maintain selected rates of use (drafts) during critical periods in the past may be determined from streamflow records through the use of a mass curve (Rippl, 1883). 1lI o o C""l 4-l .... C"I C"I (J . . . When economic considerations alone govern the design of a de o -:t o velopment, the frequency with which selected rates of regulated flow cannot be supplied by given quantities of storage become even more important than the flow during a single critical period. By using CIl 1lI CIl CIl 1lI CIl I Ql Ql II I Ql Ql I I Ql Ql II data on storage-required frequency the cost of providing sto.rage can »» »» »» be weighed against the loss of revenue due to the insufficient flow. lI'lll'lll'l .... -:t C""l\0 \0 lI'l OJ \0 0 0 -:t C~ Data on storage-required frequency for all gaging stations in 1lI C"I\OC""l\OO ...... o:l-:tC"lO\..;tO\-:tll'l If..f • .. northern Delaware are summarized in table 8 (in pocket at end of (J,-l •••• .... ,-l ...... \00 ...... report). The use of the data in this table is explained by specific .01 examples in the discussion of individual basins in the section of this lI'l lI'l \0 \0 lI'l lI'l\O\OlI'l lI'l\O\O lI'lll'lll'lll'lll'l lI'lll'lll'lll'lll'lll'lll'lll'lll'lll'l report entitled "Evaluation by basins". 0\ lI'lO\ 0\ 0\ O\lI'lO\ 0\0\0\ lI'lO\O\O\ .... O\,-l ...... ~O\""""""""O\""""""...... Ql ~ ~ '" ... The analyses of storage-required frequency in this report are .u co ~.... -:tC""l Xl ~ -:tC""lo:l ~ .... -:tC""l ...... co Through appraisal of the probable magnitude and frequency of C"I 54 55 opoFad aS1!q (ZS6Y-968Y) .t1!a..{-LS oa palsn!'P1! allp1.t1I s'poo:) n81..i UI l1! .taAn'l 1!u"!lsFtr:) .toJ all.t1!tps1P luapuap JO pojzad umwPC1!W JO A:manba.t..i--·6 a.t 0' NMOHS ~'lfH~ N'lfHJ. SS3"1 S'lfM ,tAO,.:I SA'lfO 3f\l.Ln03SNOO .:10 ~38WnN fV\1 n J CXI Ot> 0' 0<3 ~ 01 L gf,£ <3 I I 1IIIIIII1I1I 1 IIII1II1III I I 1£0" ~ G'l o 011 I V Ul ~ o ,,, ,. V l..LU-Jl !III !/l t=±==t~E±l±H±±±=t=t~~~tt~If~Ef~~~:8'0 0"1 ~..... ".·-,0.": ~... "."l Table 7.--Annua1 low-flow frequency for days of deficient discharge at stream-gaging stations in northern Delaware. (Adjusted to 57-year period, 1896-1952, on basis of long-term streamflow records in adjacent states). Gaging Drainage Recurrence Discharge (in mgd per sq mi) below which flow re- station area interval rnained continuously for length of minimum period indicated in column headings sq mi years I-day __ 7-da.Y __ n_n _t.?-day . 30-. Note: Figures for ~fuite Clay Creek above Newark are identical with White Clay Creek near Newark. I-day minimum flow for Christina River not determined due to flow regulation. SAWIft~_40_ --- O££_. 00£ oa a.3 013 0lIl ()l;l 031 06 09~. OE~ 0 - ~---t~~ 01 3~ 39lllIH:lSIO "'101 iO 31'11 ~ 01 ~'O'lSIO 1't':lI1Y3A _IX'o''' 31<1 All 03NMH3130 SI 3!l't'l1OJ.S ~NIONOdS3YYO~ ON'o' 3NI1 l~WO 3H1 L1~~~~ iO 3d01S 3"1 All O3N1flY3130 3Y'O' S31'O'Y HWO 15~ a ~ ~3d 0, ~ 3'<1 ~O H~' 3"1 1_ 031101d MO'H _ iO SOOlll3d S/1OIll't'II YO~ 3!llMOSIO iO 3IWl10A 3IU NO 03S't'8 SI nll't'"NI'O' 3!llM<~IO ''0'101 ~O 3IIlln~ A ~~ .. ~~ ~ . ~~ M I rgw~'O'A'O' 3OO'O'~IO ,..~~~V v// /"'1 Ot ~ V z ~v/V V ~ c-: / V / O! ~ /V/ V / / 0.1 ~ III os Y3d 00" 83"0 ~O H'O'lIO '0' SMQ1'" '" " /: /V III os Y3d ~ OE iO AJ.r.l¥df~ »flf01S '0' ~ / ~3llllIY.l3Y ~-~31di1't'X3 ''O'AY31NI Y't'3' &a-Y / 08",c o / /V i / ! /// [Y ( I001 / j $ flood heights, the risk to life and property can be evaluated for any selected severity of flooding. Storm drains. culverts, and bridges can be designed on the basis of flood frequency and economic consid erations. The base data and the methods of analyses used in the ALLOWABLEDRAFT IN MILLION GALLONS PER DAY PER SQUARE MILE appraisal of flood frequencies innorthern Delaware are outlined be low. 'OJ II The aim of studies on flood frequency is to predict for any site ~. .. ~ the flood discharge and flood height corresponding to a selected re .. curr'ence interval. The method used develops the magnitude-fre .. I---- s'1l quency relations by (1) expressing in a curve the general flood [;; Z > ,I--- I frequency characteristics of the region (ratio of a given flood to the I "3b:l"3"'l ~ mean-annual flood), and (Z) developing a curve of mean-annual flood i:l~iii@ > I---- '1l e- expressed as a function of the drainage area. These two factors [;;E;~> .... establish a magnitude-frequency relation which can be used for any I---- rntjl>1--'HHO b "3Zt"'1 ~ drainage basin within the region. On the basis of current accepted .1--- gj0f;jt:j x practice. the flood-frequency relations were established using only -I---- H »[;;5; Z the annual flood peak for each water year of record. Thus, the re t:~h::tl H oot"'t>l :IO:::tloO sults signify how often. on the average the annual peak will reach the ~, f;j~:E:§3 "'l diecharge corresponding to a selected recurrence interval. The I---- [;;t>l>::tl t"' o"'~ recurrence intervals were computed as (n + 1)';' m. where n equals t:l>'1l0 ~ II If/1/ ::tl'1lt"'t>l W /1 / "I 1/ the number of years of record, and m equals the order of relative ~ '-- ~~~H > magnitude of the event arranged in decreasing magnitude. A 45~ "3H"3Z H j 1/ J/ "3~~~ e- I / I II year (1911-55) listing of annual peaks for Brandywine Creek at '-- o ::tl f;j II ~H":: 1/// Chadds Ford, Pa. is given in table 9 in detail for illustrative pur~ ? "'[!: [;; / 1// ..... lJ10 / I I PQses • '-- 0> • ~ v xo xoo> 71 /, / /1// !/ II I-- °t:l'1lXZ For flood-frequency studies the m ethod using the graphical mean I--- '1l!:l8° 1/ .II II II 1/ / ia more stable and reliable than that using the arithmetic mean be gj",'1l~ II / cause a flood of high frequency within a short period of record will I--- ",.o!:l@ I/ // II .ox > / 1/ / I /I II I I unduly influence the arithmetic mean. The graphical-mean annual I--- XH~~ H 1/ I/II / III flood is taken as the intersection of the graphically fitted flood-fre I--- x I , , I--- H 77 fl II I I quency curve and the Z. 33-year recurrence-interval line, based on the theory of extreme values, (Gumbel. 1945). This line is shown 1// / 1/1//1'I 'III II on fig. lZ as a dashed line. II II 1/ 1/ II 1/ 7/ I Investigation of 11 gaging-station records within and su r eounding / nor the r n Delaware showed that 4 records within or close to the area II III I 1// J I had homogeneous flood characteristics. These were Christina River at Coochs Bridge, Del., White Clay Creek near Newark, De l ; , Red ...... N lJ1 0 ? I--' N ~ U1 o "'0 '"0 0 Clay Creek at Wooddale, Del., and Brandywine Creek at Chadds lJ1 Ford, Pa. , which lie more or less in a straight line running north STORAGE REQUIRED IN MG PER SQ MI northeast. These four stations were used in developing the flood { frequency relations for the area. Shellpot Creek at Wilmington also I IIIII IIII I is within the area, but the order numbers of the peaks of record could not be established due to lack of correlation with any other record; it was therefore omitted. The record for Brandywine Creek was complete for the past 4Z years, and was used as a basis for cor relation for an adopted Z4-year period(19Zl-55)oftilis analysis with the White Clay 61 60 19-year record for Creek. Table 9.--Annua1 flood peaks on Brandywine Creek at Chadds Table 9.--Continued. Ford, Pa., 1911 to 1955. Annual floods (Recurrence interval = Years of record + 1 = n + 1 = 45 + 1) Order m m Year Month Day Gage Dis by water year height charge Order Recur- Reference (m) rence Year Month Day Gage Dis inter height charge Order Recur Reference val (m) rence (feet) (cfs) (years) inter'" val 1948 Sept. 10 9.61 6,190 25 1.84 (feet) (cfs) (years) 1948 Dec. 30 9.10 5,360 29 1.59 1950 Aug. 3 8.65 4,690 33 1.39 1911 Aug. 31 8.84 5,050 32 1.44 Record began 1950 Nov. 25 12.54 11 ,600 6 7.67 1912 Mar. 13 11.00 8,620 11 4.13 8-1-11 1951 Dec. 21 9.49 6,050 26 1.77 1913 Apr. 28 7.8 3,900 38 1.21 1953 Jan. 24 9.63 6,200 23 2.00 Dis- 1914 July 15 7.18 3,380 41 1.12 1953 Dec. 14 7.27 3,460 40 1.15 continued 1915 Aug. 4 14.70 16,500 3 15.33 1955 Aug. 19 14.64 16,300 4 11.50 12-31-53 1916 Har. 22 6.3 2,740 43 1.07 Hlgh-wa.ter 1917 Jan. 22 8.3 4,430 36 1.28 mark in 1918 Jan. 12 11.8 10,200 7 6.57 gage well 1919 July 22 10.25 7,180 18 2.56 1920 Mar. 5 15.0 17,200 1 46.00 1920 Dec. 1 6.0 2,260 45 1.02 The annual flood peaks on White Clay Creek were correlated with 1922 Feb. 20 8.0 4,100 37 1.2l, those on Brandywine Creek and with those on Big Elk Creek, which 1923 Apr. 29 7.0 3,2.20 42 1.10 adjoins the report area. The average values adopted were used for 1924 Jan. 16 10.0 6,840 21 2.19 correlation with the remaining 2 stations and thus the order numbers 1925 Feb. 11 10.5 7,700 17 2.71 for each of the years in the 24-year period were computed for each 1926 Feb. 25 9.4 5,900 27 1. 70 (;If the short-term records and used in the analysis. 1927 Sept. 19 10.10 7,'olD 19 2.42 1928 Aug. 18 11. 00 8,620 12 3.83 The regional curve presented in figure 12 gives the ratio of flood 1929 Feb. 27 9.77 6,520 22 2.09 flow to mean annual flood (dimensionless) as ordinate, and the re 1929 Oct. 2 8.47 4,670 35 1.31 currence interval (in years) as abscissa. The regional curve pre 1931 July 10 10.80 3,240 14 3.29 .ented in figure 13 gives the mean annual flood (in ds) as ordinate 1932 l"iar. 28 9.06 5,460 28 1.64 and drainage area ( in sq mi ) as abscissa. Because of the small 1933 Aug. 24 14.01 14,800 5 9.20 .number of station records used to develop the curves, they can be 1934 IV"~r. 5 8.48 4,670 34 1.35 considered as only approximate representations of the flood-fre 1935 July 9 10.0 7,000 20 2.30 quency relations for this area. 1936 Jan. 3 11.21 9,000 9 5.11 1937 Feb. 22 7.76 3,790 39 1.18 EVALUATION BY BASINS 1938 June 27 11.37 9,400 8 5.75 1939 Aug. 20 10.72 3,060 15 3.07 1940 Har. 15 9.65 6,190 24 1.92 In this part of the report the drainage basin of each stream in or 1941 Feb. 8 3.92 5, ,)60 31 1.48 flowing through northern Delaware is described briefly as to lo 1942 Aug. 9 14.30 16,o00 2 23.00 cation, physiography, geology, area, available streamflow records, 1942 Dec. 30 9.08 5,360 30 1.53 de.cription of gaging stations, storage ponds, and spring discharge. 1944 Jan. 4 10.6 7,830 16 2.88 Examples are presented to illustrate the use of the tables. The gag 1945 Sept. 19 10.37 8,240 13 3.54 ing .tation. are described in U. S. Geological Survey Water-Supply 1946 July 23 11. 14 8,310 10 4.60 Paper Il72, p, 2.36-242. 1947 July 8 6.00 2,500 44 1.05 63 6Z I \I) 9,000 , I -e. 8,000 ....-. / NORTHERN DELAWARE REGION V 7,000 ~ MEAN ANNUAL FLOOD VS. 6,000 - DRAINAGE AREA /" ~ 5,000 / 0 Z H 4,000 / A /' 0 0 ./ H ./ IZ. 3,000 1.00" ~ V § V < / ~ 2,000 V ~ I/ 1,500 V V 1,000 10 15 20 30 40 50 60 70 80 90 100 150 200 300 400 500 Figure 13. --llelation of mean &DI1Ul flood to dr.... ~:fOz eulNDlll in nol'tJaern De1&ware• . "~7;",~:: ·'\"'Z~ I A 2.0 f I o ./ 9 :31. I 1%.1.8 1/ ~ I ~ / 1. 7 I / ~ 1.6 I V ~ 1.5 I /v ~ 1.4 1 V ~ 1.3 I / ~ 1.2 1 ~ 1.1 / 1/ § 1.0 VI S .9 I%. 1 I%. .8 V o ...-/ o .7 I H V 1 ~ .6 I ~ .5 ----- I I Wl IJ. 12 1.'3 1.5 2 2.33 3 4 5 6 8 10 20 30 40 RECURRENCE INTERVAL, IN YEARS Figure lZ. --Relation of ratio of mean annual nood versus frequency at four stream ~ gaging statioDB in northern Delaware based on the Z4-year period, 19ZZ-55. -e Delaware River Stoney Creek and other small Piedmont Tributaries to the Delaware River The water of the Delaware River is fresh upstream from the end of tidewater at Trenton, New Jersey. The average discharge of the Delaware River at this point for the last 42 years is about 12,000 Several ungaged small streams south of Naaman Creek and north cfa , In the 50-mile reach between Trenton and the Delaware State of Christina River, each having drainage areas of less than 5 sq mi line additional fresh water enters the Delaware from tributaries at their confluence with the Delaware River, drain Piedmont areas. in Pennsylvania and New Jersey but becomes mixed with the saline The basin of Stoney Creek, most important of these streams, con water in this reach. As the utilization of this saline water is pri tains Bellevue Reservoir, a water source and storage for the Wil marilya question of water quality no further discussion is givenhere. mington Suburban Water Co. The drainage area above Bellevue Detailed discussion of the quality of this water is presented in the Reservoir is somewhat less than 2 sq mi. section on quality of water under the subheading "Delaware River". Christina River Basin Naaman Creek Christina River drains 568 sq mi, of which 29 percent ( 166 sq Naaman Creek, at the northeastern edge of New Castle County, mi) is in northern New Castle County, and the remainder is in Pen drains 13.7 sq mi which is about equally divided between Pennsylvania nsylvania and Maryland. The Delaware part of Christina River basin and Delaware. Water from this stream is used by the Arden Water represents 60 percent of the area covered by this report. Twenty Co. and the Colorado Fuel and Iron Co. (see table 30, p, 172. Ex nine percent of the drainage basin of the Delaware part of Christina cept for a strip of thin gravel and sand deposits on the slopes bor River basin is gaged. This gaged area is in the Piedmont province dering the Delaware River, the basin is underlain by gabbroic rock whereas most of the remaining ungaged drainage area is in tidal of the Piedmont province. reaches of the Coastal Plain. Although gaging-station records are not available on this creek The major subbasins of the Christina River basin in Delaware five di s cha r g e measurements of base flow have been made on the are gaged and are listed in table 3, p, 42 . These subbasins are South Branch of Naaman Creek about 2, 000 ft upstream from Marsh discussed separately under the following headings: Shellpot Creek, Road in Arden, Delaware. This si\e has a drainage area of 3. a sq mi Brandywine Creek, Red Clay Creek, White Clay Creek above Newark, ( including 1. 0 sq mi in Pennsylvania), or 28 per~entof the total White Clay Creek below Newark, and Christina River above tidal drainage area of Naaman Creek (see table 2, p, 40 ). effect. The saline waters in the tidal reach of Christina River are discussed on page 152. Table 6 (p, 54 ) presents the results of these five discharge measurements and shows the estimated minimum daily discharge Shell pot Creek for a 2-year-recurrence interval to be O. 118 mgd per sq mi. This estimate, which is based on relating the five discharge measure ments to the discharge at the gaging atatronon streams in the ad Shellpot Creek (drainage area, 9.54 sq mi at mouth) is a tribu joining basin shows a unit yield about twice that for Shellpot Creek. tary to Brandywine Creek and adjacent to Naaman Creek. It warrants The discharge measured at the site on SouthBranch Naaman Creek attention because of its potential for water development and especial is from the headwater area, whereas the discharge for the Shellpot ly because of its proximity to Wilmington. gaging station includes flow from the downstream area. . The low-flow frequency, table 5, p, 52 , indicates that a site on The results of chemical samples obtained at the time of theOct. ·Shellpot Creek for a plant demanding a minimum (7 -day) flow of 0.25 5, 1955 discharge measurements are tabulated in table 21 in the mgd (at a 10-year recurrence interval) would require a drainage area section for quality of water. of 8. 3 sq mi (0.25 mgd x O. 030 mgdsm). This site would be down stream from the gaging station and hence the plant would have to be located in the Coastal Plain. The storage-required frequency, table 8 (in pocket), indicates 66 that furnishing a storage of 4. 1 mg (8. 3 sq mi x O. 5 mg per sq mi) the minimum output by 50 percent (at a 10-year recurrence interval) would practically double this minimum output (at 10-year recur and give 75 mgd ( 297 sq mi x 0.252 mgdsm). With this amount of rence interval) and give O. 46 mgd (8. 3 sq x O. 056 mgdsm). The storage the probability is only 1 in 10 that the annual minimum 7-day small size and low unit yield of the basin will probably preclude flow for any year would fall below 75 mgd. This is more than double much development frotn this source. the present 34.5 mgd peak monthly withdrawal by the Wilmington Water Co. and would be in addition to flow provided by existing stor Shellpot Creek basin lies exclusively on gabbro and its weathered age in Hoopes Reservoir. At present only about 12 mgd of the flow clayey soil. The basin is devoid of the upland gravels that cap the of Brandywine Creek is utilized by industries. divides on the gabbro areas of Brandywine Creek and Naaman Creek. Moreover, the gabbro itlleli appears unusually dense, and there is The drainage basin for Brandywine Creek is underlain by more relatively little spring discharge to Shellpot Creek. These rock than 19 distinct rock types, and the headwaters, elevation about 750 characteristics are responsible for the relatively low base flow of feet above mean sea level, are higher than those of any other stream the stream. crossing northern Delaware. The only darns now on Brandywine Creek are small dams for diverting water. but 4 storage-reservoir Brandywine Creek sites have been considered. A sediment-rating curve for the gaging station at Wilmington de Brandywine Creek, the largest and most important tributary of veloped by Wolman (1955, fig. 21) shows that for a flow of 333 mgd, Christina River, serves as awater supply for the city of Wilmington. Brandywine Creek carries about 100 tons a day of suspended sedi some of the suburbs, and many industrial plants within the city. At. ment. Wolman concludes that Brandywine Creek has a stable chan its mouth, Brandywine Creek has a drainage area of 32,9 sq mi of nel in equilibrium. which 90 percent (297 sq mi ) is in Pennsylvania and the remaining 32 sq mi in New. Castle County. At its mouth the drainage area of Kaplovsky (1954, p , 5) in a report, "Comprehensive study of Brandywine Creek is 90 sq mi larger than that of the main branch of pollution and its effect upon the waters within the Brandywine Creek the Christina River at their junction (see table 2, p. 40 ) but, nev drainage basin" concluded that Brandywine Creek is a satisfactory ertheless, is classed as the tributary because of the change in narre, source of water for domestic supply; that the coliform index has been reduced materially since 1930; that there has been a threefold re The 6 years of concurrent records available for the stations on duction in turbidity since 1948, which might be partially attributed Brandywine Creek at Wilmington" Del., and a station formerly op-; to improved contour farming; that the higher bacterial counts occur erated on Brandywine Creek at Chadds Ford, Pa. , show an agreement ring during increased flows and cooler weather maybe attributed to within 3 percent in the average cfs per sq mi at the two sites, with washings from pasturelands; that mineral quality has not changed the Wilmington station showing the higher unit yield. The long-term . materially in the last 23 years; and that some upstream developments Chadds Ford record shows a high degree of correlation with the may constitute a potential hazard for pollution. Wilmington record in the range from low through medium flow. For flood peaks, however, concurrent records for a number of storms Red Clay Creek reveal a marked flattening effect on the flood wave between the two stations . .Any attempt, therefore, to estimate flood stages or peak discharges at Wilmington on basis of Chadds Ford gage readings or Red Clay Creek, the principal tributary of White Clay Creek, discharge records should include also a careful study and analysis has adrainage area of 54.0 sq mi at the mouth, of which 62 percent of the associated storms and the hydrologic factors involved at each (33.3 sq mi) is in Pennsylvania (see table 2, p, 40). The basin is site. developed in the rnaturely dissected area of the Wissahickon for mation. Most of the water taken from Red Clay Creek for municipal The low-flow frequency. table 5 (p. 52 ) mdi cate s that at the and industrial use at Kennett Square. Pa. is again returned to the Pennsylvania-Delaware State line (297 sq mi drainage area)Brandy stream after use. wine Creek would have a 50 mgd discharge (297 sq mi x O. 167 mgdsm) for the minimum 7-day flow (at a 10-year recurrence interval). A feature of the gaging station at Wooddale, unique to the report area, is the water-temperature recorder which was placed in oper The storage-required frequency. table 8 (in pocket) indicates ation May 1953. Figure 14 shows maximwn and minimwn water that storage of 594 mg (297 sq mi x 2.0 mg per sq mi) would increase temperatures for each month from May 1953 to September 1955. 68 69 The low-flow frequency, table 5 (p. 52.) indicates that at the Pennsylvania-Delaware State line ( drainage area 2.8. 3 sq mi ) Red Clay Creek has a 4.2. rngd discharge (2.8.3 sq mi x O. 150 mgdsm) for the minimum 7 -day flow (at a lO-year recurrence interval). ~ g 'B s ~ ~ The storage-required frequency, table 8 ( in pocket) indicates Water temperature in degrees Fahr. that storage of 84.9 mg (2.8.3 sq rrri x 3.0 mg per sq mi) would in crease the minimum 7-day discharge by 86 percent (at a 10-year i "I recurrence interval) and give 7.8 mgd(2.8. 3 sq rni x O. 2.75mgdsm). •... May A study of table 8 indicates also that with a storage of 3 mg per sq ~ ~ J'me mi (or greater) Red Clay Creek would have the greatest discharge I I per sq mi of all 5 major basins in the report area. July t; Aug. Pollution on Red Clay Creek has been studied by Kaplovsky (1952.) ~ Sept. who concluded that water from Pennsylvania entering Delaware was e slightly polluted, and that water from Red Clay Creek joining White •II• Oct. Clay Creek at Stanton, Delaware, was very polluted. Efforts since ... 2- Hov. uogo that time to clean up the industrial wastes have been partly success "" Dee. ful, and in 1955 somewhat less pollution was reported on Red Clay r. ·uo~J• Jan. Creek. - .Po feb. White Clay Creek above Newark -~ Mar. I.. Apr• The headwaters of White Clay Creek are in south central Chester May County, Pennsylvania, between the basins of Big Elk Creek and Red J ~ June Clay Creek, which are on the west and east, respectively. White ~Ju1y Clay Creek flows generally southward and at the Pennsylvania-Del .' J aware State line the Christina Ri.,.er headwaters lie between White Aug • Clay and Big Elk Creeks. White Clay Creek continues flowing south . " ': •. '1 Sept. of flows 1 ward to the Fall Line just north Newark, and then eastward. Oct. White Clay Creek at the Pennsylvania - Delaware State line has a drainage area of 62..4 sq rrri (see table 2., p. 40 ) and is the second Nov. largest tributary (162. sq mi) of Christina River. Its importance to Dee. the report area maybe considered second only to Brandywine Creek. f Jan. Water taken from White Clay Creek by the Delaware Water Company S'.. Fe-D. is distributed to many parts of northern New Castle County for both ~ domestic and industrial users. Also water from this creek is used Po Mar. by mills along the creek banks in the vicinity of Newark. y ~ .Apr. ~May The 3 years of record for the gaging station on White Clay Creek 0.. above Newark would normally be inadequate for low-water studies June but because of the good correlation with the l6-year record on the ~ Juiy gaging station downstream, conclusions reached for the drainage t:. Aug. basin downstream from Newark may likewise be considered appli Sept. cable to the basin upstream from Newark. The upper part of the White Clay Creek basin is incised chiefly in metasedimentary rocks--schist, rnigmatite, and marble--of the 71 70 Glenarm series. Numerous springs discharge from these crystal The gaging station formerly operated on Mill Creek at Stanton is line rocks. described as follows: The low-flow frequency, table 5, (p, 52) indicates that if aplant Location. --Lat 39 042'51", long 75 039'58", on right bank 10 demanding 15 mgd selected a site on White Clay Creek at the Penn ft downstreamfromhighwaybridge, 1 mile west of Stanton, New sylvania-Delaware State line (62.4 sq mi drainage area) the natural Castle County. minimum 7 -day flow (at a 10-year recurrence interval) would be 8. 7 mgd (62.4 sq mi x O. 140 mgdsm) or 42 percent deficient. Drainage area. --12.4 sq mi (revised from published 12. 3 sq mi), represents 94 percent of total at mouth. The storage-required frequency, table 8 (in pocket), indicates that storage of 187 mg (62.4 sq mi x 3. 0 mg per sq mi) would raise Records available. -- July 21, 1931 to October 31, 1933 the minimum 7-day flow (at a 10-year recurrence interval) to 16.2 (discontinued). October 1931 to October 1933 in reports of the mgd (62.4 sq mi x 0.2.60 mg per sq mi), neglecting evaporation and Geological Survey. July 1931 to October 1933 published byPenn seepage losses from reservoir or artificial diversions from the sylvania Department of Forests and Waters. stream. Gage. --Staff gage. Altitude of gage is 25 ft above mean sea White Clay Creek below Newark level (from topographic map). Extremes. --1931-33: Maximum discharge not determined, The White Clay Creek near Newark gaging station is downstream occurred Aug. 23,1933 (gage height, 6.0 ft); minimum, 0.8 cfs from the station discussed above. Sept. 20, 1932 (gage height, 0.49 ft); minimum daily discharge, 1.2 cfs July 29, Aug. 1, 7, 8, 1931, Sept. 20, 1932. Both gaging stations on White Clay Creek for concurrent records (1953-55)havepracticallythe same yearly discharge in cfsrn so any Remarks. --Records fair except those above 100 cfs , those of the tributaries between the two stations may also be considered" estimated, and those during ice effect, which are poor. to have approximately the same surface-water yield per sq mi. Cooperation. --Pennsylvania Department of Health, Salinity From Newark to the mouth of Red Clay Creek the drainage area Survey. increases from 71 to 104 sq mi (~eetable 2, p. 40). Practically all of this increase in area is in New Castle County with 2/3 of the Creek heads in a broad valley' underlain by Cockeysville increase accounted for by Middle Run ( 4. 13 sq mi drainage area ), crosses steep ridges of schist of the Wissahickon forma Pike Creek, (6.61 sq mi drainage area), and Mill Creek, (13.2 sq and flows through knobby gabbro hills before reaching White mi drainage area). " .. ,y Creek. The headwater area in Cockeysville marble is more .@;~,~tly.rolling than the ridge and valley area of the Wissahickon Mill Creek enters White Clay Creek downstream from the lower '2,\,,:.,'·l'matlon. gaging station. Historically, Mill Creek was the pioneer stream ...... ~~,;.:l, t-.,,:.:. gaging station in Delaware with a streamflow record from July 21, :.i:3''''"i Table 6 (p. 54) presents the results of five discharge measure 1931 to Oct. 31, 1933. The gaging station in Nhite Clay Creek near '§f:;' ,.ments made during 1955-56 on Mill Creek at the old gage site and Newark was established Nov. 30, 1931, and operated continuously shows the estimated minimum daily discharge for a 2-year recur until Sept. 30, 1936, so a period of twenty-three months of con rence interval to be 0.219 mgd per square mile. current records is available at these stations. The correlation of monthly discharge for Mill Creek and concurrent data for White Clay Samples of water for analysis were obtained at the time of the Creek defines a curve essentially parallel with the drainage- area :Oct. 5, 1955 and Nov. 17, 1955 discharge measurements and the relationship. According to the discharge relationship the yield per results tabulated in table 21 in the section for quality of water. square mile for Mill Creek during that early period was found to be slightly less than for White Clay Creek. However, five discharge The drainage area of White Clay Creek below Red Clay Creek measurements on Mill Creek made during 1955-56, when correlated and above its confluence with the Christina River is only 4 sq mi. with concurrent daily discharges for White Clay Creek at the gaging station, indicate equal yield per square mile. 73 Christina River above Tidal Effect Small Stream Basins in the Coastal Plain Tributary to Delaware River The headwaters of Christina (also Christiana) River are in south central Chester County, Pennsylvania and northeast Cecil County, Maryland. The stream flows southeasterly passing northeast of All streams tributary to the Delaware River between the mouth Chestnut Hill and Iron Hill and then flows easterly to the Delaware of Christina River and the Chesapeake and Delaware Canal are east River. ward flowing streams entirely within northern New Castle County. Of these streams, only the discharge of Red Lion Creek has been Christina River at a point downstream from White Clay Creek measured. Five low - water discharge measurements were made has adrainage area of 216 sq mi , of which 162 sq rrri is contributed during 1955-56 on Red Lion Creek (see table~,p. 54) at the bridge by White Clay Creek (see table 2, P> 40). Downstream from the on Delaware State Highway 7 about 1/4 mile south of Red Lion, Del mouth of White Clay Creek Christina River becomes a tidal estuary aware (junction of Delaware State Highways 7 and 71). These five and drains an area of 22 sq rni to the mouth of Brandywine Creek. measurements when correlated with daily di s charge for gaging sta The water in this reach is somewhat brackish but nearly 2 rngd is tions on Big Elk Creek at Elk Mills, Md. and Leipsic River near used by industry for cooling and washing purposes. The limiting Cheswold, Del. indicate that the estimated annual minimum daily factors for the potential use of this water will be the degree of con discharge (for a 2-year recurrence interval) at the site of the meas tamination by sewage effluent and the degree to which the dis charge urements is 0.074 rngd per sq mi. The drainage area at the rrieaa-' rate of the tidal changes can remove this contamination. Christina uring site on Red Lion Creek is 3.20 sq rrri, or about 34 percent of River at the mouth of Brandywine Creek has a drainage area of 567 the total at the mouth. The drainage areaof two other streams (Mill sq mi, of which 329 sq rni is contributed by Brandywine Creek. From Creek and Dragon Creek) tributary to the Delaware River in this reach the mouth of Brandywine Creek to the mouth of Christina River the also exceeds 5 square miles as shown in table 2, p. 40. drainage area increases only 1 sq mi. Tributary to Chesapeake and Delaware Canal The data on low-flow frequency shown in table 5, [p, 52) indicate that the minimum 7-day flow (at a 10-year recurrence interval) ata site with a 19 sq rrri drainage area is 1. 14 rngd (19 sq rni xO. 060 Several small streams in the Coastal Plain of the report area mgdam). drain southward into the Chesapeake and Delaware Canal, two of the • largest being Lums Millpond outlet and Guthrie Branch with drainage The storage-required frequency, table 8, (in pocket) indicates areas of 4. 36 and 2.74 sq mi, respectively (see table 2, p, 40). that storage of 38 mg (19 sq rrri x 2. 0 rngds m] would raise the min Streamflow records are not available fo r these canal tributaries. imum output (at a 10-year recurrence interval) to 2.6 mgd (19 sq rni x O. 138 rngdam }, more than double the rate without storage. Tributary to Chesapeake Bay These tables indicate, however, that even with 38 million gallons storage on Christina River upstream from Coochs Bridge, Delaware the minimum 7-day yield per square mile would be less than the Two streams in New Castle County north of the canal drain west actual yield without any storage for Brandywine Creek, Red Clay ward through Maryland into Chesapeake Bay. These are LongBranch Creek, or White Clay Creek. Although comparatively low on basis a tributary of Back Creek, and Perch Creek, a tributary of Elk River, of Brandywine Creek, White Clay and Red Clay Creek, the yield of with drainage areas of 3.69 and 2.00 sq rni, respectively, in Dela Christina River is practically double that for Shellpot Creek. The ware, (see table 2, p. 40). Streamflow records are not available only storage now in the basin is the relatively small amount in Silver for these Coastal Plain streams. Lake, a recreational lake on an upstream tributary of Christina River and Smalleys Pond ( 40 million gallons capacity) downstream from Estimated Average Discharge gaging station. The headwaters of Christina River are developed on crystalline rocks, chiefly gabbro and granodiorite. As all the records for the 6 gaging stations in the report area reflect the surface - water yield from the Piedmont province, the stream-gaging record for Leipsic River near Cheswold, Del. is the nearest source of data for the Coastal Plain. In the 14 years 74 75 of records, 1931 - 33 and 1943 - 55, this 9.2 sq mi drainage basin GROUND WATER had an average discharge of 10.8 cfs ( 1. 17 cf s m or 0.756 mgdsm) and a minimum daily discharge of 1. 2 ds. Other gaging stations Successful exploitation of ground-water resources depends upon in the Coastal Plain in Delaware farther south on Marshyhope Creek knowledge of general principles of the hydraulics of ground - water near Adamsville and Gravelly Fork near Bridgeville showed average flow and methods of well development, and specific information on discharges of 1. 15 and 1. 13 cfs per square mile, respectively, for the water-bearing characteristics of the local geologic formations. 12 years of record (1943-55). As these principles are briefly discussed, an attempt is made to indicate their relative influence upon the development of water sup Based on the assumption that the average discharge of the small plies, so that the succeeding sections on water utilization and po stream basins of the Coastal Plain in the report area is 0.75 mgd tential development will be meaningful. per s qua.r e mile as shown by the l4-years of record on Leipsic River the estimated average discharges are as summarized in table 10· GENERAL PRINCIPLES By W. C. Rasmussen Table 10. - --Estimated average discharge for the larger drainage basins of the Coastal Plain of northern Delaware north of the Chesapeake and Delaware Canal. The general principles of ground-water hydrology and the re Estimated covery of ground water have been written in technical reports (for Coastal Plain drainage basin Drainage area average example, Meinzer, 1923), college textbooks (Tolman, 1937; Wisler and 1949; and Geyer, 195~,foreign (Keil in Delaware (sq mi) discharge Brater, Fair treatises hack, 1935), such of (1942), (mgd) reference works as that Meinzer prac tical guides (Bennison, 1947), and general works (Thomas, 1951), to lista few representative sources. Marine and Rasmussen (1955, Mill Creek near New Castle p. 49-72) gave a surnmaryof these principles for Delaware. There (Army Cr. ) 6.39 4.79 fore only a brief review is given here. Red Lion Creek 9.28 6.96 Dragon Run (Creek) 8.80 6.60 Ground-Water Hydraulics Lums Millpond outlet 4.36 3.27 Guthrie Branch 2.74 2.06 Long Branch 3.69 2.77 The modes of occurrence of ground water, and of soil water, are Perch Creek 2.00 1. 50 shown in figure 15. Strictly speaking, ground water occurs only in Total for major basins 37.26 27.95 the zone of saturation, either unconfined below the water table or confined under artesian head between clays or other impermeable media. Water in the zone of not ground water, but, from The total average discharge of about 28 mgd from the 7 streams aeration is down, vadose and is a significant quantity of water. It cannot be ignored in the overall the surface soil water, intermediate water, water problem of storage, and of ground-water recharge. of the capillary fringe. Two properties of the rock, the porosity, or percentage of pore space, and the permeability, or ease of movement, are of value in considering storage and transmission of water in rocks. These properties are illustrated in figure 16, which also summarizes fac tors influencing them. They are expressed quantitatively in terms of the coefficients of storage and transmissibility, illustrated in figure 17. The coefficient of transmissibility may be defined as the amount of water that moves across a unit cross section of the formation under a unit hydraulic gradient. In Am.erican units it is expressed as gallons per day per foot, and represents the number of gallons 76 77 ~ .... Q t ~ I'Ij ~ ~ ,.," ::a "Cl s a :::t ::!' "0 Q . ,.. 0' .... i ! ".... :'.;' ::a s, .- ,,~ .~., §= ~s q ~ ~ ~ il~~q:- ~ ::a ~ 0 ~ ~ ; ....c:: ~ ~i'1".. ::a ~ >II "'3"Cll ~ ~ ::a § 0 q, .. q,:, ~ .... ~~ ~ q, 1 "\ " ~'~ ~Q :2 .. q:- "" " " "(D 0 " 0 ~ o •• ;" • 0' I . oI 0 Iii' "" ~ .~ "o o "Po i nl" " ~ u -.~ 79 7-8 , ,/ I per day that will pass through a section of the aquifer 1 foot wide. , , extending the full thickness of the aquifer, under a hydraulic gra ,I ,( dient of 1 foot per foot. Another way of visualizing the coefficient , I I , under terms more suitable to hydraulic gradients normallyencoun I , tered in the field is to consider it as the number of gallons per day / I I I passing through a section of the formation 1 mile wide. and full I , saturated thickness. under a hydraulic gradient of 1 foot per 'mile. • , ,I I , The coefficient of transmissibility is equal to the product of the I , I , average field permeability of the aquifer and its saturated thickness, i I , in feet. § I !II' l I 1 " I I I The coefficient of storage under water-table conditions is a meas I , ure of the specific yield. or volume of water that will drain out by , I , I gravity divided by the volume of the aquifer drained, plus water re I I leased by elastic compression of the aquifer and associated beds as ,/ , the water level declines. The coefficient under artesian conditions u , , 't , , represents only the water derived by elastic compression, as the ,I ,I aquifer remains saturated and no water drains out by gravity. The '"c. I '~ I , coefficient of storage of an aquifer is defined as the volume of water , , it releases from or takes into storage per unit surface area of the \. I ,I I aquifer per unit change inthe component of head normal to that sur , , face. Characteristic ,CoefficientJi,.Q-L.s.t.o.I' The wells and springs of northern Delaware were studied by .... ~.;!" " • ~ bIl means of a systematic inventory. A canvass of wells of all types- ~~ • ~ .S dug, driven, bored, jetted, and d,rilled--has been made on a geo • Cl" 0~ '0 ~~ .::..c: graphic basis, to obtain representative characteristics--diameter, .... depth, water level, yield, and so forth. In all I, 511 wells and springs > ,,'" ~fa were inventoried. u 0 ..J u .:: .; .,. .... ::1 This canvass has ranged from complete, or 100 percent cover o " .0 A.~ age, in areas ofintense development (for example, the Newark area), IS' .0 ill .. to about 5 percent coverage in the area north of Wilmington. It is .. e " estimated on the basis of census figures (1950), population growth 0 .. ~~ ~ 0 ~.:: (1950-55), density of houses outside the urban area, and drainage I fiI I studies as d.etermined from recent maps and field reconnaissance, a) that there are about 6, 100 wells and springs in northern Delaware. ~z- .... Therefore, the well and spring inventory represents a coverage of M A R N D .. "::I about Z5 percent. This coverage is not entirely representative, how ...bIl ever, because greater effort was made to obtain data on logged wells, r.. which are almost invariabl y'cirilled wells. Moreover, of an estimated 1&1 IL. % 800 springs in the Piedmont only 51 were inventoried. The wells are located by means of a lettered grid which divides the area into 5-minute quadrangles of latitude and longitude, as shown in figure 18. These quadrangles are lettere dfromnorth to south with uppercase letters and from west to east with lowercase letters. A specific quadrangle is thus indicated by two letters, the 83 8Z r l I. capital letter being given first. This system of quadrangles has been in use since the well and spring inventory began in Delaware in 1950. Fo rme rl y, the wells were numbered consecutively in the order visited, and these are the numbers listed in each well table under the column headed "fo r me r well number, 11 and published in Bulletins 2 (Groot and Rasmussen, 1954) and 4 (Marine and Rasmussen, 1955), . . or in the Annual water-level reports (Andreasen, 1953; Marine and' I I I . ~ .~.~'.'. Rasmussen, 1954; Marine, 1954; Boggess and Coskery, 1955;Coskery I I I . andBoggess, 1956; Coskery, 1956). The wells in most quadrangles '..'0·, ...... finally became so numerous that consecutive numbers were in the I "~,, . hundreds, and it required careful search to locate a reference well I I . " . on the map. The old system, therefore, defeated its purpose, which ~..g~<:'l..... was the accurate and rapid location of a well. I .: ~~".::~'. F'o r this report (see Vol. II), each 5-minute quadrangle is sub ~. divided into 25 one-minute quadrangles. These are designated 11 ... to 15, 21 to 25, 31 to 35, 41 to 45, and 51 to 55, successively, in ~ .".: e :..: .. f .: •. groups of 5 from north to south, and consecutively within eachgroup '. .... from west to east, as for example 31, 32, 33, 34, 35 in the one · .' ,., • Q' minute row centralto each quadrangle. This systemis usedon each · . .. . . ·'•.. The wells are plotted on 11 maps and 4 inserts, which will be published in Volume n of this report. The well logs and well tables .... , II I I I I provide the basic data from which the ground-water evaluation has . '.' I been made. ." .. :. ' ... :':':.'.~'~ ~..• ..'..' ... ':: A word is in order here about methods of well construction. An '.' '.' , ... I .. o ' . adequate well is much more than a hole in the ground, it is a scien ...•.. tifically designed and soundly engineered structure for taking water :.~. ~>'....'~~',' .' .. from the ground. Figure 19 illustrates a well developed in sand and .. ". I I .: ~.·... 0 ;,-. .,':- gravel. The envelope of coarser material in the vicinity of the screen :: " . .: :':',': . . .' a maybe developed, by careful and prolonged overpumping, by surging, \I •..• ()...... or by gravel packing. In other types of aquifers, other techniques I ~0'·'- Q) ". ~.'.•.. 0 : . I-r such as fracturing with fluids, shooting with explosives, or acid I ::l I '.. '. . · ...... bll izing may be used to develop a well. Careful selection of a screen ~ I I ·.·.'0.:~',"..C) by the drilling contractor also, is an important factor in the perform ... ' ':~....: .':. .. ance of a well. Screen material, either bronze, iron, stainless steel, . '. I .: ...... concrete, or plastic pipe, should be chosen with regard to the chem ., '., ~, '. . II .. ' " I istryof the well water, and the possibilities of corrosion or incrus ',' . I O. '. '0' . II I I . ; ... ', tation. '. The efficiency of a well is measured by its specific capacity, or yield per unit drawdown, generally expressed at gpm per foot. For example a well with a specific capacity of 10 gpm per foot is con- 84 85 -<:tOOC"'lO"It'lr-t o ...... side red to yield 10 gpm with one foot of drawdown, 50 gpm with 5 "-o .... N..;I'-o..;l'OO o ..... Net1 o feet of drawdown, and 100 gpm with 10 feet of dr awdown, from the r-t static level to the pumping level. This straight proportion does not hold strictly, for the gain in yield tends to be somewhat smaller for each increment of drawdown and also declines with time. Neverthe less, the specific capacity is a useful rule-of-thumb measurement of well capacity, and, when many wells in one formation are com . pared, the average and range of specific capacities indicate th.e Ql general capabilities of the formation. The specific capacity is ac tually a combined measure of the well efficiency and the formation -0 efficiency. If the well is completely developed, the specific caE~c- ~d et'lOOOOr-tC"'ll""l o 00· ..ity!-s. rouglil y com.J.l_~abl':_!~E!coef!~c::.iE!~!of~I'CI.llsIl1illsi1:>i~itr, N C"'I r-t, r-t is in the.!~edim.e_~~?~~.lJIlits'_I~':!..~~tlength. The geologic source also has an effect on the optimum yield of o the well. Consequently the study of well samples, the compilation of well logs, and the classification of geologic source form an im 000000r-t0 r-t 00· N N r-t r-t portant part of the study of underground reservoirs. Although a conscientious effort was made to establish lithologic and stratigraphic correlation, by means of the sample and drillers 0'\ logs, studies of outcrops, and heavy - mineral and paleontologic 1t'l0000..;l'r-tO It'l· r-t " work, many of the classifications of geologic source are open to some question. The formation chosen was determined by the logs of surrounding wells, the depth and location of the well in question, and interpretation of regional structure. C"'I · Table 11 is a summary of the age distribution of wells by type. It shows that more than a third of the wells were constructed in the last 5 years, and about 60 percent in the last 15 years. Dug wells dominate the wells constructed before 1910. Cable-tool wells were lI"l predominant in the decade 1911-l9Z0. Jetted wells became prom -0· inent in the decade beginning with 19Z1. Hydraulic-rotarywells did not appear until the decade beginning 1941. Drilled wells, both cable tool or rotary, have become increasingly popular in the last Z5 years. o IbNr-tOr-fOaooO C'i· It is estimated that there are about 800 springs in northern Dela N ware. Eighty-four percent of the springs are in the Piedmont portion 0'\ and 16 percent are in the Coastal Plain. The discharges of 18 sprin,s 50 C"'I ..... were measured for this report and ranged from gpm(DclZ-ll_1 00 C"'I· O. 1 ..;I' to gpm (Bc3Z-4l, and averaged 8.0 gpm, These spot measure ments were made over a period of 5 liZ years, and indicate mainly that spring flow is small to moderate. The largest spring measured, 50 gprn, flows from Pleistocene deposits overlying nonm ar ine Creta" ceous sediments, in the valley of the Christina River, on the Coastal Plain. 11 For all approximate well locations see Plate Z. The well maps with the exact location will be published in Volume II. 87 Table 12.--Heasurements of flow and temperature of 4 Water from springs is used chiefly for domestic and farm sup springs in the tiedmont of norther,.l De1aw·are. plies in the Piedmont. The Bellevue reservoir, an abandoned quarry of gabbro which is used as a water source and storage by the Wilm ingtqn Suburban Water Company is fed by springs. On the Coastal Spring Ad 51-1 Eb %-11 Be 32-L, Ed 21-1 Plain, seepage areas in which the flow emerges over a broad sur Heathered Heathered face, are more common than springs. Geologic Hissahickon Coclceysvd,lIe T-Jissah i.ckon Uissahickon source fonnation marble forma t Lon [Orm.3. tion About fifty years ago, spring water was popular for health pur Date Flot-l Temp. F1m'1 Temp. Flow Temp. F]m-1 Temp. poses. The "baths," as they were called, became resort areas, (gpm) (oF) (gr m) (01':2- (gr m) ~F) (grm) J..:!iL both here and in Europe. Brandywine Springs, on the west edge of Wilmington was popular locally. These waters were analyzed by the May 17, Board of Health (Brown, 1904, p. 220-221) and no particularly effi 1950 3.5 cacious properties were recognized. Indeed, Brown reported con Jan. 1"u, ditions atthe springs in 1904 which made them subject to pollution. 1955 e o. ] Jan. 31 2.1L, The fluctuations in flow and temperature have been measured Nar. 1 2.25 49.5 3.0J 0.17 monthly during 1955 and 1956 in four small sp r ing s in the Piedmont. Mar. 30 3.00 Lf9.5 3.GO 51.5 0.20 {,6. C 17..0 51.0 and are shown in table 12. The lowest flows recorded in this short en .... May 2 2.57 51.5 o. 50~: 53.0 0.26 ':h/.v 6.92 52.5 period were measured in July 1955 after 26 months of accumulated June 1 2.22 53.0 2. L:·O 55.0 0.2 Lf 53.5 deficient precipitation during which period many other springs were July 1 I.Ss 5Lf.5 2.31 56.0 0.23 56.0 3.00 57.0 reported dry. The highestflows inBc32-4 andBd2l-l were record July 28 1.80 57.0 1.72 59.5 0.14 60.0 ed one month later at the end of August 1955, and high flows were Aug. 30 5.29 5~63 0.G7 10.59 recorded in Ad5l-l and Bb34-11. These high flows were due to the Oct. 3 4.61 57.0 5.63 56.0 0.55 60.0 L:·.29 58.0 rapid rise in the ground-water table as a result ofthe recharge sup Oct. 27 4.09 56.0 6.Lf3 56.5 0.35 57.0 2.51 57.0 plied by heavy rains accompanying two hurricanes, "Connie" and Dec. 2 3.05 "53.0 5.29 5L•• O 0.34 5D.O "Diane" which struck Delaware less than a week apart, August 13 Jan. 3, and 18, 1955. A near-record precipitation of 12.09 inches for the 1956 3.08 50.5 4.92 53.5 0.26 46.5 month of August was recorded at New Castle Airport (see fig. 20). Feb. 1 2.79 Lf9.5 4.64 53,0 0.28 44.0 6.90 48.0 The temperatures of these springs ranged from 44 0F in the winter Mar. 5 3.51 49.0 5.00 53.0 0.32 lf5.0 9.63 52.0 to 60 0F in the summer. 1'1ar. 31 6.78 L,8.0 7.20 52.5 0.46 45.5 4.62 50.0 Apr. 30 6.66 6.67 0.57 10.59 Temperatures of water from 60 wells and 4 springs were meas June 1 6.09 54.0 7.06 55.0 0.42 5L,.O 5.5[: 5L,.O ured and given in the well tables, in the remarks section (see Vol. July 2 3.00 56.5 6.43 55.0 0.25 56.5 II). Temperatures ranged from 44 0F for water from a spring to 59. 50F for water from a well 190 feet deep. The temperatures in the springs and s hallow wells are probably more a function of s ea e estimated son than of depth, whereas in the artesian wells temperatures vary Hater pumped from spri.ng recently. only slightly with the season. The measur ernente of ground-water * temperature are useful to thos e interested in air-conditioning, cool Springs are most numerous in the westernhalf of the Great Circle ing, or in building heat pumps in this area. sector, in the outcrop of the Wissahil:konformation. These springs are small, and most of them issue from crevices within a few tens Fluctuations of Water Level of feetofthevalleybottoms. They provide the base flow of the Brandywine, Red Clay, and White Clay Cr€'eks. Springs in the gabbro areanorth of Wilmington are less common, and, because of the less The water level in wells is an indication ofthe height of water in er local relief of the plateau-like gabbro area, those on the upland the ground-water r eae rvoi r s, and is an indirect measure of the a frequently go dry. mount of water in storage. Water levels rise during wet seasons and decline during drought, but the precise significance of these rises and falls, in terms of water available, can only be determined when the reservoir hydraulics are understood. 88 &9 Figure 18, the index map, shows the observation wells in north ern Delaware for which records are available. The se records have been published in annual federal water-supply papers (Andreasen, 1953, for the calendar year 1950; Marine and Rasmussen, 1954, for 30 .. 11"\ ~ Ir"I '4 a Ir. r\ the caf enda r-ye.ar 1951). The water-level records for the calendar ; ~ o New COI"I \ , T\ I \ , f ~ T years 1952, 1953, 1954, and 1955 have been published as State Water ~5 Coynl, \ , , T j ~ , 1 ~ao , 1 , Level Reports I, 2, 3, and 4 respectively (Marine, 1954; Boggess Airport \ f , I \ \ j "\ fTO , I \. I and Coskery, 1955; Coskeryand Boggess, 1956; andCoskery, 1956). .. .. V V V V \1 •0 The measured water levels in 5 of the observation wells, and the Z40 Z•• precipitation and the average monthly temperature at New Castle Air '"11\ f n Z.. port for the period 1950 to 1955, have been plotted in figure 20. No rV \ f'l \ Z31 pronounced trend is apparent for this short period, although a gen V \ ,... , Z•• eral rise in the water table was experienced in 1952, a year of above !'II. \ \f Z•• average precipitation, and relatively low water levels were record IJ \ \ 2'4 ed inperiods of subnormal precipitation, such as 13 months in 1950 'I I 51 and 23 months in 1953-55. J\ • I t " \ • ~ The water levels, when not disturbed by pumping, generally Cb51-lS ... \ '0 •0 a follow an annual cycle, high in the winter and early spring, declin • UniVII',ity farm \1 v : !I' PI,i,tocene .. rill ---+---¥+----+---f----.-+1I-4---f.-.,--+----.j• 19 u ing in late spring and early summer, low in late summer and early T ilZ Wot,,-to". · i autumn, rising in late autumn. This cycle is a fair duplication of "13_ condition. -, !\'I \. I TT ; e I the inverted temperature curve, as compared in the uppermost graph .! ~ .!: of figure 20. However, the water-level graphs are one or two months 21---+---~1-'=_+-1I___--_+---':::.Jl~"r---_+---1---+--_____j'-1\ u ! •• :ii .a s- Ec 42-1 in phase than the temperature cycle. This because the \ 2 : later is j nlor • ~ summer and early fall recession of the water table is in large part .54 Sf. •• oro.. •I a due to evapotranspiration which does not cease until the first killing 5 Plei.'oclne •• ,111 ---+---+----+---f-----4---I---+----.j • • frost, whereas temperature reaches its peak in July. .. Wot.,·tatlfe ! ! condition. li • .... Aberrations in the water-level cycle reflect extremes ofprecip • ~ itation or drought. Precipitation is fairly well distributed and aver 4 .. ages between 3 and 5 inches per month throughout the 12 months, • but 6 or more inches of rainfall in a month provides immediate re away charge to the water table and less than 2 inches of rainfall in a month, 301---+---+---+---_+---+--:--_+---1---+--_____j 15 permits greater-than-average declines in water levels. 301---+---+---+-.,.--_+---+-+---.-_+---I---+--_____j 20 A ... ~1\ 45"'---- Ec 15·15 \ 30 GEOLOGIC FORMATIONS AND THEIR WATER Gov. Bocon Healtll Cent.r 1'1 10 Maootl'l, formation 1----+------\----ft'""""tl---tt-'l+-t+ft-+--+-----\f---f-----4---+J 1Il BEARING CHARACTERISTICS 40 &5 Ar'"ian. inftlke , ... ,rol \1 \ I eomU•• a_oy,---+-----1----'-<'--+--.+--t---L--'--''t-----+---t------1v .. 'J 00 The geologic formations of northern Delaware have been named from type localities in New Jersey, Maryland, and Pennsylvania, and extended by surface and subsurface correlation to this area, by ~ Countf+--'----..--I---.,..rJ---.-_+----'-+---_+--I-I---+~-_____j the work of many geologists. Although much is known about these i' A;,por' -+_~-I-::-I+---:-::--.I- _.~ • I formations, must still remains to be learned. Table 13 summa rizes the geologic units, aquifers, and aquicludes in northern Dela ... '.50 '"' I.az Ii I.... ~lri'li-n~~-.-.+-~---I... ware. Plate 3 is a generalized geologic map of northern Delaware. Figure 21 is a geologic cross section, showing the complex relation ship of the principal fo rrnatfone of the Piedmont, and plate 4 is a 91 90 cross section showing the more regular arrangement of the strata levels do not need to build up near the surface to induce flow at the of the Coastal Plain. necessary rate. Table 13 is arranged in order of increasing geologic age, from Table 14 summarizes the maximum, minimum, and average younger to older, progressing from top to bottom. The oldest rocks yields of wells tapping the various geologic sources. Table 15 sum are hard and dense and yield water at relatively low rates or not at marizes the corresponding specific capacities. Where the number all. The sedimentary rocks of the Cretaceous system consist of tough of wells representing a formation is small (arbitrarily, less than 10), clays and slightly consolidated sands, which yield water at low to the sampling error is conversely large, and the average should be moderately high rates. The sediments of the Tertiary and Quater used with caution. Wells in tables 14 and 15 are wells for whi c. nary systems are relatively soft, unconsolidated silts and sands, the yields were reported by the well drillers. They are usually impor sands yielding water at moderate to high rates where they are suffi tant industrial, municipal, or estate wells. Therefore, small-ca ciently thick to be productive. pacity farm and domestic wells are only sparingly represented. A single formation may contain one or more aquifers (water The tables show'that the Pleistocene series has by far the high yielding beds) and one or more aquicludes (water-retaining beds), est max.i!!1um_.Yi~4J..!..il50gpm), highest average yield (260 gp~. or may be almost entirely an aquifuge (water-impervious bed), ac and highest specific capacities (56 spm/ft maximum and 19 gpm/ft cording to the classification of Tolman(1937, p. 36-37). Fortunate avenge). A fact the table does not reveal, however, is that the ly no formations in Delaware can be classed truly as aquifuges, and Pleistocene series usually has only a few tens of feet of available most of those classifiedas aquicludes are slightly leaky, capable in drawdown. The aquifers of the nonmarine Cretaceous have high max places of small yield to wells. The aquifers are sand, peat, schist, imum yields (800, 500, and 540 gpm) and moderate average yields and marble, and the aquicludes are greensand, silt, clay, and some (104, 89, and 100 gpm). However, their specific capacities are rel crystalline igneous rock. atively low (2.0, 1. 6, and 2.3 gpm/ft), so if the nonmarine Creta ceous aquifers did not lie relatively deep and did not have high non Table 13 shows the average depth to water in the geologic units pumping water levels which provide adequate drawdown, production for which information was available as it was during the report period from the formations would not be so promising. The Magothy for (approximately 19~0to 1955). The number of wells used to compute mation and Bryn Mawr(?) gravel are relatively thin, so larger ca the averages are shown parenthetically, as a statistical guide. The pacitywells are few, yields are modest, and specific capacities, are weighted average water level in northern Delaware was 20.6 feet be low. low the land surface during this pe r iod, The average water level in the State as a whole ranged from 5 to 9 feet and was mostlybetween Crystalline Rocks and Their Weathered Products 7 and 8 feet below the land surface (Marine and Rasmussen, p. 90) during this same report period. It would appear, then, that water By R. F. Ward and W. C. Rasmussen levels in northern Delaware are 12 to 13 feet lower than in the State as a whole. This is due in part to the greater relief in northern Dela ware and in part to greater pumping rates there. Fairly extensive The geologic map, plate 3, includes in its upper half the results cones of depression have developed or are developing in the Newark, of a recent remapping of the Piedmont in northern Delaware by Ward New Castle, and Delaware City areas, as a normal result of large (1956). The division of the Wissahickon formation into three facies scale ground-water operations. is, perhaps, the most important modification of the work of earlier geologists. The crystalline rocks are shown on this map with no In the crystalline rocks, the greater depth to water in the Wissa regard for the thickness of the weathered zone, although in places hickon formation in contrast to the gabbro, granodiorite, and mar this untransported residual material mantles the rocks completely ble is probably an expression of the more dissected topography of and extends to depths of several tens of feet. the area underlain by the Wissahickon. In the sedimentary rocks of the Coastal Plain the water is at somewhat greater depth in the non Figure 21 is a generalized cross section of the crystalline rocks, marine Cretaceous aquifers, in the Magothy fo r mation, and in the in relation to the sediments of the Coastal Plain. It is generalized Wenonah sand than in the Pliocene(?) and Pleisfocene series. The because it is not based upon reliable subsurface data in the' Pied greater depth probably is due to the relatively greater thickness and mont portion, but is an interpretation of data obtained at outcrops continuity of the older aquifers, which enable them to discharge at and extrapolated to greater depths. It is the writers I modification low hydraulic gradients the water they receive, so that the water of similar sections, covering larger portions of the Piedmont, pre pared by the late Florence Bascom and her co-workers (BaSCOm, 93 Table 13. --Gharacteristics of geologic formationa in Dorthern De1sware. Average Average ;0 thick- depth to Systam Geologic units ness in Physical character water 8ur- Water-bearing ft (no. face in ft character "'" of wells (no. of istics ~ we1h ~ ---- average) average) Alluvium Recent Estimated Sand and gravel 1n Estimated Generally and series 20 in Plecboont valleys, 2 in permeable. soU valleys sUt and clay along valleys Delaware River. Soil profile about 1 foot thick on Quaternary UPlands. Channel P1e1sto- Columbia 36\)7lir-i!iJ-.t.lind gray un- 17 (348) Unconfined sand fill cene group consolidated sand and sUt. Ex- and series and gravel t with cel1ent aquifer estua- lenses of silt and where 8uf- rine clay. Ucient1y thick, de- bu t too thin in posits many places to be very pro- Unconformity ductlve. Tertiary Upland Pliocene Bryn Red and orange 15 (4) Yields small (1) sedi- (1) Mawr 39 (6) gravelly and quantities of ments series (1) silty sand. water 1n a few gravel Utlconfonnlty places. Red Rust-brown fine to 25 (12) LocaHy an Bank 17 (18) medium well-sorted aquifer.. Sand sand subrounded quartz thin and of sand wi th some small extent. glauconite. Upper Undiffer 25(2) Dark-greenIsh-crown An aquiclude in entiated fine glauconitic . most places. Navesink quartz sand grading A few wells Marine marl and into dark-green to derive 81Il&11 l10unt black coarse silt quantities of sedi Laurel with abundant glau water. ments Creta sand conite. ceous Wenonah 15 (28) Rust-brown and gray 27 (6) A minor aquifer. sand well-stratified fine micaceous quartz sand wi th some Rlauconite. series Merchant 45 (34) Dark-greenish-brown An- aquiclude.. vU1e very fine micaceous, clay glauconitic quartz sand with consider- ~:~ ___ Unconformity _a!!.b~1~e:....!s~io:1.l:t...;a~n~d~c:.!1~a:.lY"" _ Tranai- Msgothy White l1gnitic sand 35 (6) Not an extensive tiona1 forma- 26 (40) and black clay with aquifer. The sedi- tion abundant carbona- sands act 8S a ments ceous material. hydrologic unit wi th the upper aquifer of the Creta- underlying ceous lJneonform1ty sediments. Upper l!9!!ifer Limited sand Predominantly fine 28 (49) lenses which Raritan, . to medium sand wi th give high yields Conti- Patapsco, conaidereb1e sUe, in a few places; nental, and 571 (12) very sUty and non- Upper Patuxent Aquicludes of varie- of law specific marine and forma- gated sUt end c1ey. capacity in sedi- lower tiona, 1II8Ily places. ments Creta- undiffer- Water sometimes ceous entiated irony. series in the sub- Middle aguifer Limited sand surface Predominantly fine to 34 (47) lenses wh1ch medium sand w1th ...... give high yields sUt. in some places, moderate to law Aquicludes of varie- y1elds e1se- gated sUt and clay. where. Lower aguifer Extensive sand rredominant1y fine to 2U (35) lenses giving ccaxse sand, some silt. high yields in many places, Lguicludes of varle- moderate to &ated sUt and clay. low y1elds elsewhere. Unconformity Igneous Paleozoic inatru- Gabbro, granodiorite, Gabbro Aquifers of (1) sive lndafinite and serpentine with 17 (101) re1ative.ly rocluo rocks pegmatite and Crano- small y1e1d, smph1bolite d1kes diorite adequate for and Crysta1- 15 10 domestic and line G enarm Wissa- Indefinite Schist, gneiss, and 4 1 farm. purposes. Pr_- rocks series hicl:on (probably mi8matite. Water occurs brillD (meta- forma- a few in fractures (1) sed1ments) tion thousand and fissures, feet) and in the rocks Cockeye- Indefinite Sunary, micaceous 13 (18) weathered -e ville (probably marble. overburden. \II marble a few hundred feet) Clark, and others, 1909; Bascom and Miller, 1920; Bascom and Stose, 1932). The crystalline rocks yIeld water from the weathered zone at their top, from fractures, or from both. Yields and specific capac,:" GREAT CIRCLE Z .-.-,-PeQmoljl. di~.1>Z ities are relatively low. However, wells penetrating the gabbro and f'TI the Wibsahickon formation near streams have larger maximum and average yields and Specific capacities than do wells distant from streams, as they are in a position to receive recharge through the o "'"'0 e ! .. ...... Small stock alluvium. These yields should not be regarded as typical for other n D. !. ~ ,.. • _.'" ,..., topographic locations. •o 3'" 'C• ..~n0 o ::! ::r ..... A!l1>~"">"<:'Amphiboliledike E .0 • .~ o Table 16 summarizes the average thicknesses of the weathered .. ~ ,..n .. "It e . Z zone above the crystalline rocks. The average, ll.O feet, based ~ Co ... '" • ~~ on 305 wells, though weighted to account for the areal distribution - ~D. .,cr of wells, is not entirely representative of the area as a whole, be "'n., cause the steeper slopes, where bare rocks crop out, are seldom if ! ..,-.. o ...... ~o ever the sites of wells. Therefore, the average for the whole area o· :!:n would be somewhat less. ~ 0" "C... 0 D.. ,..., PLEASANT HILL Comparison of the weighted average thickness of the weathered X zone in the Piedmont, 34.8 feet, with that of the' same or similar "'0 I rocks beneath the sediments of the Coastal Plain, 24.0 feet, sug » gests either that the zone of weathering in the exposed rocks of the [L• • Z 500 feot » Piedmont has increased by a net amount of 11 feet (since deposition ... of the Lower Cretaceous sediments halted or slowed the weathering o z of the underlying crystalline rocks), or that some of the weathered .,.. zone was eroded away before the Cretaceous deposits were. laid 9. down. Another possibility that must be considered, however, is oN that the men who drill and log wells on the Coastal plain use dif •~ ferent bits and drilling rigs (rotary or jet in preference to cable C % G) Q tool) than those on the Piedmont, and their conceptions of "soft ~'C ., o • '0 o 0" rock, " "weathered material, " and "overburden" may differ • )C 0 ~ '0 ... 0" IRON HILL o ::r :=: o n (') '"CD ti· It should be emphasized that many times 11 feet of weathering .:, o D.n o o » could have occurred in this long interval, and early weathering pro ,..n o (I) ., n,.. files been stripped away. It is probable that most of the weathered g 0 ... ,..., '" '" » on the Piedmont today was formed during the Pleistocene '0 I material '" c• or Recent epoch. • "'0 3 • I ...e i » ~ • Rocks of the Piedmont • ·~ Z - I (J) - I m(J) The rocks of the Piedmont consist of a complex of folded and meta :IE morphosed sedimentary rocks, or metasediments, and igneous rocks which have been intruded into them. The metasediments comprise a marble which is exposed in a few small areas and a dense gneissic schist which underlies about half the Piedmont. The igneous rocks are represented by a large batholith of gabbroic rock and a number 96 of smaller bodies of widely ranging composition, all of which extend 97 Table l4.--Yields of wells in northern Delaware by Table l5.--Specific capacit 1es of wells in northern geologic source. Delaware by geologic source. (Meas~rementsreported by drillers, in gallons per minute Geologic source Yield Number per foot of drawdown) Maximum Minimum Average of gpm gpm gpm wells Geologic so~rce Specific capacity Number Pleistocene series 1,050 5.0 260 49 of wells Pliocene (7) series Pleistocene series 56 .6 19 27 Bryn Y~lqr(7) gravel 60 2 23 5 Transitional Cretaceous Transitional Cretaceous unit unit r~gothyformation 2.0 .17 1.3 4 ~bgothyformation 108 11.3 65 4 Nonn~rineCretaceous units Upper aq~ifer 6.8 .12 2.3 23 Nonmarine Cretaceous units Middle aquifer 5.3 .32 1.6 21 Upper aquifer 540 7.5 100 24 Lowe'r aquifer 10.6 .40 2.0 22 Middle aquifer 500 12 89 29 Lower aquifer 800 3 104 52 Tiedmont rocks Granodiorite (igneous) Piedmont rocks Ueathered material 3.2 .005 1.6 2 Granodiorite (igneous) Hard rock 1.0 .07 .3 10 12 ,4.0 9 5 Gabbro (igneous) 15 .003 1.6 33 Gabbro (igneous) Wissahickon formation. 13 .01 .7 74 Cockeysvf.He marble W~atheredmaterial 25 4.0 15 2 (' Hard rock 120 .3 2o 75 Weathered material 2.5 1.8 2.2 2 H"issahickon formation Hard rock 6.7 .28 2.1 5 Tf!eathered material 10 .2 3.2 12 Hard rock 120 1.0 18 61 Cockeysville marble to unknown depths. Each of these classes will be treated separately. Weathered material 55 6.4 33 3 Hard rock 30 6.0 17 7 Where fresh and unfractured, these crystalline rocks have very low porosity and permeability. They yield water only where weath ering has produced partial disintegration and where the forces that have deformed them have produced open fractures. such as joints and faults. For this reason few wells in the Piedmont have a suf ficienUylarge yield for industrial purposes. but in mostplaces ade quate domestic supplies can be obtained. Metas ediments The metasediments of Delaware. the Cockeysville marble and the overlying Wissahickon formation. belong to the Glenarm series 98 99 and cover a large portion of the Piedmont province from southeast ONtOC'"IN ern Pennsylvania to northern Virginia. The Glenarm series may be r-l of late Precambrian' or early Paleozoic age and is designated Pre cambrian(?). The original sediments of the Glenarm aeries, which included sandstone, shale, and limestone, have been subjected to repeated or prolonged deformation and have been completely re -:tN.. l' a crystallized. They are now tightly folded and closely faulted quartz to N ite, schist, and marble. The folds trend generally northeast, the N C'"I planes of schistosity, or foliation strike in the same direction and,in Delaware, dip steeply, usually at angles of 60 to 90 degrees. The structural features and stratigraphic relations of the Glenarm series are treated at some length by Cloos and Hietanen (1941). The sedi ments of the Glenarm series were deposited on the Baltimore gneiss, ametasediment of earlier Precambrian age, and wells which succeed ,~ a in penetrating the Glenarm series encounter, therefore, additional r-l crystalline rocks. Cockeysville marble. --The Cockeysville marble crops out in two places in Delaware, one near Hockessin in the headwaters of Mill r-l'..o to r-l I co a Creek and the other in the valley of Pike Creek at the foot of Pleas •I ~\D2 co I to -:t anl1'Hill(see pl. 2. and 3). It was by Chester (1884)as N N N reported ocur I-lr-l ring also, northeast of Centerville. Bascomhas estimated the thick o III +J ness of the Cockeysville marble to be 2.00 feet (Bascom and Miller, t:: til 'M III 192.0), butits distribution and thickness are somewhat irregular and o Q)e,) in places the Wissahickonformation may lie directly upon the Balti t:: o Q) more gneiss. The Cockeysville appears to be 136 feet thick in well N,.t:: r-l,NO ,:J Q'\ r-l Bb34-2.. '0 Q),.s::: 1-l+J Q) III Where it crops out, the Cockeyflville marble is a dense white .c:: Q) +J t:: dolomitic marble containing lenses of schist made up of calcite and III Q) phlogopite mica. The areas underlian by the Cockeysville marble Q),.O \D \D ~ by gently rolling topography, to the co l1"\ are characterized in contrast Q) NC'"I distinct ridges and valleys formed on the Wissahickon formation. ..c: +J lI-I The water-bearing characteristics of marbles (and limestones) o are in large part determined by the fact that calcite and tliolomite are til til soluble in water containing carbon dioxide derived from the air and Q) soil. Ground waters from .j.1mestone and marble areas usually con ] o tain calcium and magnesium in solution and consequently are hard. "M -E The micaceous marble is relatively permeable and usually is Q) profoundly weathered, the dense pure marble less so. No large S solution cavities have been reported in the marble in Delaware, but Q) in nearby Pennsylvania ground water moving along fractures has dis :> < solved large quantities of material, leaving caverns of many cubic I I yards. Should a water - filled cavern of this sort be encount ered while drilling, a large water supply possibly could be developed, but the chances of finding such a cavern below the water table are considered small. 100 101 In the areas mapped as Cockeysville marble the weathered, un rocks. It is made up of quartz, sodic plagioclase feldspar, ortho consolidated material is unusually thick. Records from 12 wells clase feldspar, biotite, garnet, sillimanite, and many minor con showed a range in thickness from 15 (Bb34-8) to 152 feet (Bb34-7) stituents. In the southwestern third of the outcrop area the rock is and an average thickness of 84. Z feet, greater than the average for rich in biotite and sillimanite, is quite schistose, and usually is any other formation and more than twice as great as the average deeply weathered. In the central third of the area the schistis pre for the whole State (table 16). This is a result of the susceptibility dominantly quartzitic and feldspathic and much lower in mica and of the marble to solution by soil and ground water. The overburden, garnet. Here the schist is more resistant to weathering than it is composed of clayey and sandy materials, is presumably a residue to the southwest and is more commonly seen in outcrop. Also, in of the insoluble minerals of the Cockeysville. this area large areas of the Wissahickon formation have been abun dantly injected by gabbro and rendered dense and massive ( see pl. Anywhere in the area of the Wissahickon formation, and partic 3). In the northeastern third ofits outcrop area also the Wissahickon ularly near the areas mapped as marble, it is possible that a well formation is dens e and mas sive, garnet and sillimanite being present may pass through the Wissahickon and enter the Cockeysville. Wells in appreciable quantities. Bb34-Z and CbZ3-l, which are in areas mapped as Wis sahickon for mation, but only O. Z and 0.6 mile, respectively, from the outcrop Series of parallel fractures, or joints, are a cornrnonfeature of of the Cockeysville, log 188 feet and 228+ feet of weathered material, the schist. These are spaced from less than an inch to several feet and have probably entered the weathered marble. Cb31-8, which apart, and in a given place one, two, or perhaps several distinct penetrated llZ feet of weathered material, is at Milford Crossroads, sets of joints may be present. The best developed, and most com Z miles from the nearest outcrop of the Cockeysville, and yet it is mon, joints present are cross joints which strike approximately on the Same anticlinal trend., and could be in weathered marble. northwest and are nearly vertical. In thoroughly jointed areas the Likewise Cb41-Z, along White Clay Creek north of Newark on this rock is often deeply weathered and contains more water than where same strike, penetrated lZ5 feet of weathered material, and may be jointing is sparse. The amount of water contained depends upon the in marble. separation that has taken place at the joints. This in turnis a function of the load of superincumbent rock. Below a hundred feet or so most Water levels in 18 wells in the Cockeysville marble ranged from joints probably are tightly closed. 5 to Z3 fe§t below.the land surface and averaged 13. 1 feet during the report period. Water levels in the weathered Cockeysville (7 wells) In places where the heat of nearby gabbroic intrusions has ren averaged only 8.7 feet below the land surface, whereas those in the dered the schist massive, a horizontal joint system, forming what unweathered marble (11 wells) averaged 15.9 feet below land sur is called sheeting, is locally developed. These joints are approx face. imately parallel to the land surface and are spaced several inches apart near the surface. Their spacing increases with increasing Table 14 shows that yields of wells in weathered Cockeysville depth and they disappear at a depth of 50 feet or so. marble were considerably greater than those from wells in the un weathered marble or in other crystalline rocks, weathered or not, Where the Wissahickon formation has been faulted, large tabular albeit the sampling unit, only 3 wells, is small. The yields ranged bodies of crushed, permeable rock may lie along the faults. Few from 6. 4 to 55 gpm and averaged 34 gprn; Seven wells in unweathered faults are exposed in outcrops, but faults of every magnitude may marble had an average yield of 17 gpm; occur in the subsurface, and the crushed zones associated with them may locallyprov.ide reservoirs of greater than normal capacity and Table 15 shows that the specific capacities of wells in the Cock yield for this formation. eysville marble, and its weathered zone, are about Z gpm per foot, indicating that greater yields could be obtained from the marble by The ove rburden of unconsolidated material above the unweathe red utilizing more of the available drawdown. A yield of 100 gpm would schist is granular, or sandy, as a result of the presence of large require a drawdown of only about 5<1feet, and the formation l!as a quantities of such highly stable minerals as quartz and sillimanite. saturated thickness much greater than 50 feet in mostplaces where it occurs. The thickness of overburden varies widely. Consideririg the depth of weathering is a function of such variables as mineral com Wissahick,on formation. -- The Wissahickon formation in Dela position, jointing, and topographic position, it is difficult to predict ware has been remapped and described in detail in a recent report its thickness a!t a given location. The thickness ranged from 5 feet (Ward, 1956). The rock i-6 a dense mica schist or gneissic schist at well Cb34-3 to more than 125 feet at well Cb41-2 and averages of which underlies the greater part of the area of metasedimentary 34.4 feet in 116 wells (table 16). 103 102 WaterleveIs in theWissahickonfotn'lation are the lowest, on the ever, metamorphic hornblende or secondary quartz are conspicuous average, for any of 'thl} crystalline rocks, averaging 23. 6 feet below cons ti.tuents , the land surface in 149 wells. In the wells in unweathered rock, the water level ranged from 3 to 129 feet and averaged 25.6 feet below Joints in the gabbroic rocks are few and usually widely spaced. the land surface in 106 well. dtrrj ng the inventory. In wells in the Sheetingispresentin most exposed areas and probably provides the weathered rock the water level ranged from 2 to 42 teet and averaged most important avenue for atmospheric attack on the rock. Faults 18.6 feet below the land surface in 43 wells recorded in the inventory. and associated zones of crushed rock may be present below the sur face but none occurs in surface exposures. Reported yields of 61 rock wells in the Wissahickon formation ranged from 1 to 120 gpm and averaged 17.6 gpm. Yields of 12 It can be seen, then, that textural and structural features which. wells in the weathered products ranged from 0.2 to 100 gpm and promote deep weathering or provide small ground-water reservoirs averaged 3.2 gpm (table 14). The average specific capacity of 74 are poorly developed in the gabbro, and that although the gabbroic wells was orily 0.7 gpm per foot, although the maximum was 13.3 rocks are less stable chemically than those of the Wissahickon for gpm per foot (table 15). mation, they are not so deeply weathered. The fact that these rocks are structurally more uniform than the metasediments is reflected' The topography developed on the schist is characterized by an in the even character of their topography. Stream valleys are shal important ground-water phenomenon--springs. Where slopes are low and often swarnpy; orily a few sharp hills and steep draws are steep, in both the larger stream valleys and the smaller valleys present. called draws, the land surface often intersects the water table, and seepage zones or springs may occur. As the position of the water The weathered zone developed on the gabbro is also a poor pro table varies somewhat fr orn season to season, some springs may spect for ground-water development. The minerals present decom decline in flow or even cease to flow during dry weather. pose easily into clay, and orily in those few p lac eawhe r'e quartz is present in large quantities is the overburden likely to be sandy. One Topographically, the outcrop area of the Wissahickon formation property of the overburden which adds to the difficulties of drilling has a well-defined northeasterly trend, marked by strike-controlled or digging wells in this area is the cornmon occurrence of large ridges and valleys. The parallel valley systems would provide ideal boulders. These are produced by the intersection of the widely spaced reservoirs for surface-water storage, if each valley were enclosed joints and sheeting fractures (see fig. 22). The thickness of the by a dam. Although schist is occasionally a dangerous rock on which weathered zone as measured and recorded on schedules of 105 wells to base a dam, there are many places where the Wis sahickon forma which end in the gabbro ranges from 2(Be22-1)to 102+ feet (Da15-3) tion is sufficiently dense and gneis sic to permit construction of small, with an average of 28.5 feet (see table 16). Thethickness andnature safe dams. of the overburden is obscured somewhat by the presence in some places of thin gravelly upland sediments. These are discussedlater Intrusive igneous rocks in this report. Water levels measured in 63 rock wells in the gabbro area ranged Igneous rocks of many kinds have been emplaced in the meta £rom 0 to 126 feet below land surface, andhad anaverage of 18.1feet. sediments, probably during the Paleozoic era.' These range from Water levels recorded in 38 wells in the weathered gabbro ranged tiny veinlets of granite less than an inch thick to a large bodyof from 2 to 28 feet below land surface, and had an average of 14.7 feet. gabbro underlying scores of square miles in the vicinity of Wilm ington. The range in composition is likewise great: from veins of Yields of wells in the gabbro are extremely small in some places, pure white quartz to stocks of soft green serpentine. It appears, and in a few places "dry" holes have been reported, particularly however, that the meager yield of wells in these rocks do not range along Naamans Road. Nevertheless the statistics given in table 14 as widely~,do their mineralogy and occurrence. seem to belie this observation, for the yields of 75 wells in gabbro rock ranged from O. 3 gpm to 125 gpm and averaged 28. 3 gpm, the Gabbro. --A large body of gabbro has intruded the metasediInents highest average of the crystalline rock. These statistics must be and replaced them in the eastern half of the PiedInont of Delaware taken circumspectly, because they are heavily weighted by the re (see pl. 3). In addition, several small irregular bodies of gabbro latively high yields of 22 wells of the Hercules Powder Co. (Bc52-1 are p r e's ent within the schist. Where unaffected by later metamor to Bc52-23) wMch derive recharge from Red Clay Creek. The cor phism or additive processes the gabbro consists largely of lime-rich responding average . specific capacity, 1. 6 gpm per ft. (table 15 ) must be taken With caution for the same reason. plagioclase feldspar, augite, and hypersthene. In.mostplaces, how 105 104 Granodiorite. -- The southwestern portion of the Piedmont of the outcrop the serpentine displays many closely spaced joints. Delaware is underlain by granodiorite for several square miles (see pl. 3), which extends from Newark, De l , , to near Baltimore, The overburden on the serpentine rarely exceeds a few inches. Md., and is called the Port Deposit gneis a, This is a light-colored and the vegetation on serpentine "barrens" is usually meager. Be granite -like rock composed largely of quartz, sodic -plagioclase neath the Coastal Plain, the weathered zone above serpentine was feldspar, orthoclase feldspar, and biotite. It has a distinctly fo logged as 22 and 15 feet thick in two wells (Ca55-15 and -16). liated texture but is much more massive than the nearby Wissahickon formation. Basement Rocks of the Coastal Plain Joints and sheeting appear to be better developed than in the gabbroic rocks, and the overburden, reflecting the high quartz con The eroded surface of the crystalline rocks of the Piedznont slopes tent, is sandy. The weathered zone above the granodiorite ranges in a southeasterly direction. It passes below the sedimentary rocks in thickness from 11 feet (Da13-1 and 3) to 43 feet (Ca43-3) and has at the Fall Line and continues at an average slope of 80 feet per mile an average of 21. 8 feet in 23 wells (see table' 16). seaward. Beneath Fenwick Island just south of the southern border of Delaware, the crystalline rocks are overlain by sediments more In general, its water-bearing qualities appear to be poorer than than a mile and a half thick. those ofthe schist and the gabbro, as indicated by tables 14 and 15. However, with only 5 wells on which to base the average yield (9 Where they form the floor upon which the sediments were deposit gpm) and 10 rock wells to base the average specific capacity (0. 3 ed the crystalline rocks are known as "basement rocks ". The irregu gpm/ft), statistical comparison is difficult. lar topography of the basement is reflected in the basement-structure map (plate 5) and in the presence of Iron and Chestnut Hills. The Pegmatite. -- Several tabular dikes and sills of pegmatite are physical properties of the basement rock are likely to be similar to present in the Piedznont. These are made up of very coarsely crys those of the Piedznont crystalline rocks but the actual formation pre talline gray to white quartz and pink potash feldspar, Minor quan sent in a given place is a "matter of conjecture. tities of mica and tourmaline are also present. The largest of these bodies are a hundred or so feet wide, but most are smalle r and myriad The water-bearing properties of the rocks of the basement are small veins and dike Ieta of pegmatite are interspersed throughout the similar to those of the crystalline rocks of the Piedmont, except that schist. The larger pegmatites may be continuous for miles. artesian conditions exist. However, only small yields can be expect • ed • Most pegmatites are massive, lack foliation and are sparsely jointed. Their overburden is thin, and they generally hold little Sedimentary Rocks of the Coastal Plain promise as ground-water reservoirs. There are, however, some pegmatites in the area which have been very deeply weathered and By J. J. Groot and W. C. Rasmussen may show much different water - bearing characteristics. A large pegmatite extending from Hockessin to Yorklyn has been largely altered to kaolin. This material has been mined to a reported depth The sedimentary rocks of the Coastal Plain in northern Delaware of 90 feet, but unconsolidated material may extend below this. Those form a wedge-shaped mass, with the chisel edge along the Fall Line, pegmatites mapped near Pleasant Hill also have been largely con and the thick shank near Pea Patch Island. The cros s section, plate verted to kaolin. These kaolinizedpegmatites are in large part clay 4, indicates that these rocks thicken from the thin edge, at Newark, and therefore poor ground-water prospects. The depth of weathering to more than 800 feet near Delaware City. Structurally, they form may indicate that the pegmatite serves as a darn to ground water a homo cline. Physically, the sedimentary rocks are relatively un moving in the schist. The adjacent schists, where altered, produce consolidated, and, although known technically as "rocks" to the geol a more granular material, and therefore have better ground-water ogist, might be understood more. simply as "sediments"by the non possibilities. technical person. As discussed in the preceding section, the sedi ments rest upon the uneven basement complex of crystalline rocks Serpentine. -- About a mile north of Mount Cuba, three small and their weathered products. stocks of serpentine are mapped and additional small bodies may be present. Serpentine is a soft, green fibrous rock composed Aspects ot-the stratigraphy of the Coastal Plain of northern Del largely of the minerals antigorite and serpophite. It is consid aware were discussed by Miller (Bascom and Miller, 1920), Carter ered a hydrothermal alteration product of basic igneous rocks. In (1937), Groot, Organist, alidRichards(1954), Marine and Raamus seu lOb 107 (1955), and Groot (1955). The sedimentary formation of northern Delaware and their ages as described by Miller (Bascom and Miller, 1920) are: the Patuxent and Patapsco formations of Early Cretaceous age, the Raritan, Magothy, Matawan, and Monmouth formations of Late Cretaceous age, the Brandywine formation of PliQcene( ?) age, and the Pleistocene series. It was pointed out by Groot (1955, p. 25-26) and also noted by Marine and Rasmussen (1955, P- 42) that ~ ... lD it is not possible to separate the Patuxent, Patapsco, and Raritan z o ... o o 0 formations in Delaware accurately on the basis of lithologie char .... a: E acteristics, because they consist of very siInilar materials • c{ z c{ These formations a re nonmarine in Delaware. as shown by the ...J Q. smallfragments of lignite, the lack of marine fossils and thelentic X ular, channel-type deposits of sand, silt, and clay. These nonmarine W Cretaceous sediments contain a lower sandy zone, a middle sandy (f) zone with clay lenses, and an upper silty sand zone separated by zones of variegated silt and clay. The water-producing sand zones are called, in this report, the lower aquifer, the middle aquifer, and the upper aquifer. The silt and clay zones act as aqui cludea, It is realized that the division into three aquifers is an oversimpli fication of the true situation, as in some places the lower and upper sediments are too silty or clayey to be considered water-bearing, whereas the middle sediments frequently contain considerable thick nesses of clay which act as aqui.cludes , Yet, the threefold division used is a workable approximation of the true situation in most local ities in northern Delaware. The Magothy formation is well exposed in the banks of the Ches apeake and Delaware Canal. It is considered transitional between the nonmarine Cretaceous sediments and the marine Upper Creta ceous deposits. The Magothyformation is not an extensive aquifer, and, where resting on the sands of the upper aquifer, forms a hy drologic unit with it. The stratigraphy of the marine Upper Cretaceous deposits was discussed by Miller (Bascom and Miller, 1920), who divided these sediments into the Matawan and Monmouth formations. Carter (1937), however, raised these formations to group rank, dividing the Matawan into the Crosswicks clay, the Englishtown sand, and the Marshal.Itown formation. According to Carter, the Monmouth for mation is represented in the Chesapeake and Delaware Canal by the Mount Laurel sand. Groot, Organist, and Richards (1954), however, found that the Matawan in northern Delaware consists of the Mer chantville clay and the Wenonah sand, whereas the Monmouth group is represented by the Mount Laurel sand, the Navesink marl, and the Red Bank formation. Evidence supporting this interpretation is described in Bjlletin 3 of the Delaware Geological Survey. The no menclature of Groot, Organist, and Richards (1954) for the Mata wan and Monmouth groups in northern Delaware is used in this co- 108 109 operative report, but it differs somewhat from the less recent us (Ec13-6) to 680 feet, and has an average of 571 feet. The increase age of the U. S. Geological Survey. in thickness is ill\lstrated in the c ro s s section, plate 4. The Merchantville clay, and the undifferentiated Mount Laurel The nonmarine Cretaceous sediments contain three aquifers, sand and Navesink marl function chiefly as aquicludes, but the We designated the lower, middle, and upper aquifers. The lower, mid nonah sand and Red Bank sand are aquifers of minor importance. dle, and upper aquifers are not considered to have time significance but are believed to be separate reservoirs. Each reservoir appears The Tertiary system is represented in northern Delaware by to be composed of overlapping channels, that range widely in lithol sediments onthe uplandnorth of Wilmington. The upland sediments ogy and permeability. The intake areas of these aquifers are not are relatively thin, nonfossiliferous sands and silts covering small known but in general probably strike parallel to the major bedding areas on the gabbro complex. They are questionably assigned to the and follow the outcrop bands symbolized in plate 3. Mineralog Pliocene series, and, following Bascom (Bascom and Stose, 1932) ically the lower aquifer is in part within a basal impoverished zone, listed as Bryn Mawr( ?) gr ave I, and in part in an overlying staurolite zone. The middle aquifer is entirely within the staurolite zone. The upper aquifer has a thin The Quaternary deposits cover the Cretaceous deposits nearly upper segment of the staurolite zone overlain by an impoverished completely, and consist of unconfined sands and silts occurring on zone. the Coastal Plain, and overlapping small areas on the Piedmont. The intervening aquicludes are apparent in logs, but their ex Cretaceous System tent and structure are known only in the same generalized way that the aquifers are known. The Cretaceous system in Delaware has both the Lower Creta The lithology, as determined from the well logs, and sample ceous series, now considered to be represented only by the Patux logs, of the lower, middle, and upper aquifers, is compared in ent formation, and the Upper Cretaceous series, representedby the table 17. In spite of a great range in description within each aquifer, nonmarine Patapsco and Raz-rtan foz-matdona, the Merchantville clay, the size range and the averages are remarkably similar. The aver the Wenonah sand, ,the undiffe r entf.ated Mount Laurel sand and Nave age description of each is a "medium to fine sand and silty sand, " sink marl, and the Red Bank sand. and the average thickness recorded in the wells is 40 feet. There is a very slight decrease in grain size with decreasing depth, from Nonmarine sediments lower to upper aquifers, apparent in the total weighted percentages. Lower aquifer. --The lower aquifer is formed by the lower sandy As discussed previously, the accurate lithologic separation of zone of the nonmarine Cretaceous sediments. This zone consists the Patuxent, Patapsco, and Raritan formations is not possible in of sands with some silts and clays. The sands are white, gray, buff, Delaware although in a few places in Virginia, Maryland, and New andlight-brownincolor, fine to coarse, usually angular, well-sorted Jersey, where plant and vertebrate-animal fossils are found, these to poorly-sorted and are often crossbedded. The aquifer also con formations are locally distinct. Groot (1955) has divided the non tains intz-afor matdonaf conglomerates, and in nearby Maryland, marine Cretaceous sediments into mineral zones, each having a coarse basal gravels have been reported (Clark, and others, 1911, characteristic mineral suite. The lower staurolite zone was called p. 59). Most of the fine-grained sediments of the lower aquifer are the Patuxent zone. The upper heavy mineral zone, characterized variegated silts with red, white, and gray the predominant colors. by the stable minerals zircon, rutile, and tourmaline, was called the Patapsco-Raritan zone. These names do not imply that the heavy The sands generally have been deposited in channels rather than mineral zones coincide precisely with geologic formations, because in sheets. In the vicinity of New Castle, such a channel was discov neither the zone nor formation boundaries can be determined on a ered and its extent outlined with the aid of numerous test borings. lithologic basis. The existence of sands of limited lateral extent is also indicated by the logs of test holes drilled in the Delaware City area for the Tide The nonmarine Cretaceous sediments comprise the bulk of the water Oil Company (see pl. 4). sedimentary deposits inDelaware. The thickness ranges from a few inches near the Fall Line to 680feet in well Dc53-7. In the 12 wells Waterlevel~eportedormeasured in 89 wells in theloweraqui which log the entire thicknes s (from the basement to overlying tran fer, during the report period, ranged from above the land surface sitional Cretaceous sediments), the thickness ranges from 454 feet III 110 to 92 feetbelowland surface andaveraged 28.4 feet below land sur o 00 o. CO coo face. One well was reported flowing, under low head. No extensive \0 N· 00 N· .-; C"'l 11'\ 11'\ r-I o cone of depression has yet been recognized (June 1956). C"'l Although the lower aquifer is one of the most important ground 11'\ o \0 water reservoirs in northern Delaware, the nature of the sediments 11'\ o· N· N N r-I described imposes certain restrictions as to the quantities of water r-I which can be developed from it at a specific locality. The occur rence of the sands in channels is responsible for difficulties in pros . o. 00 00 pecting' as two test holes a few thousand feet apart often penetrate o a a-.. water-bearing sands at somewhat different depths. Also, the rapid -.T N -.T lateral and vertical changes from coarse to fine sands make it haz ardous to predict the yield of wells developed in it, because the rate of ground-water movement depends on the transmissibility of the N 11'\ \0 o co which, a function of the r-I a N sediments, in turn, is grain-size distribu "r-I· N r-I· tion and thickness. The extent and nature of the intake area, that is, the area where o C"'l C"'l water c an errte r the sands of the lower aquifer, is of great hydrologic -::t \0 a o 11'\ importance. The intake area is represented by the region where the lower aquifer is overlain by the permeable sands of the Pleistocene series, or is actually exposed at the surface. The approximate in take area of the lower aquifer is shown roughly on plate 3. It is o 11'\ o. 11'\ o· 11'\· o bounded in the north by the contact with the crystalline rocks of the C"'l r-I o Piedmont, and inthe south by the contact with overlying aquicludes. ..-t Yields reported for 52 wells in the lower aquifer ranged from 3 o o a gpm to 800 gpm, and had an average of 103.9 (see table 14). Com r-I N CO C"'l N N .. pared to the yields of the middle anA upper aquifers. the lower is r-I the best. Comparison of their specific capacities (table 15) shows 2.0, 1. 6, and 2.3 for the lower (22 wells), middle (21 wells), and co a- \0 upper (23 wells), respectively. Considering their similarity in grain . 11'\ \0· o· sizes and aquifer thickness, this higher yield may be due to the C"'l r-I greater available drawdown of the lower aquifer in the area as a whole. o a o "11'\ o Middle aquifer. - -The middle aquifer consists of variegated silts C"'l N r-I and clays, with interbedded sandlenses. The fine-grained sediments generally highly oxidized, and red the predominant color. The It.I are is It.I • sands of the middle aquifer range widely in grain size, but are similar ~g 11'\ to those of the lower and upper aquifers, in general fine to medium o sand and silty sand. The outcrop belt of the middle aquifer lies between the outcrop belt of the lower aquifer in the northwest, and that of the upper a quifer to the southeast. The boundaries between these units were determined on the basis of their difference in texture, and textural changes occur also within each unit. As a result, the establishment of the boundaries is subject to the personal judgment of the investi gator. This does not mean that the division of the nonmarine Creta lIZ ceous sediments into three aquifers is without value, because in the large capacity wells have been developed in the upper aquifer, and majority of cases this division can indeed be made. those producers who are favorably situated above a buried channel may have plenty of water. Water levels in 47 wells in the middle aquifer ranged from 1 to 84 feet below land surface and averaged 33.9 feet below land sur Water levels in the 49 wells in the upper aquifer ranged from 2 face. Yields of 29 wells were reported or measured. The minimum to 55 feet below land surface and averaged 28. 3 feet below land sur yield was 12 gpm, the maximum, 500 gpm, and the average, 89.4 face. One well (Ec22-3) flowed 25 gpm in February 1952, with the gprn, The middle aquifer has the lowest average yield of the three discharge pipe at an altitude of 16 feet above sea level and 6 feet aquifers in the nonmarine Cretaceous sediments and also has the above land surface. lowest average specific capacity 1. 6 gpm/ ft, based on records from 21 wells (see table 15). Yields of 24 wells in the upper aquifer ranged from 7. 5 to 538 gpm and averaged 99.9 gpm (table 14). The specific capacities Plate 6 is a composite log of a deep test hole to the basement ranged from O. 12 to 6.8 gpml ft and averaged 2. 3 gpml ft. This was rocks at New Castle. The upper aquifer, screened between 115 and a better average specific capacity than either the lower or middle 130.5 feet below land surface in Cd52-13 a production well, has aquifers, yet higher yields from the upper aquifer are more diffi yielded 538 gpm. One sand in the middle aquifer, that between 264 cult to obtain. This is because of the lower available drawdown of and 284 feet, yieldttd little water in a bailer test. Three other sands, the upper aquifer--in general, producing sands are developed be the 13-foot section between 327 and 340, the 6-foot section between tween 100 and 250 feet below land surface in this aquifer in northern 344 and 350, and the 10-foot section between 370 and 380 feet below Delaware. It takes 150 feet of drawdown to make a 345 gpm well land surface, deserve a test. It would be advisable to core these with an average specific capacity of only 2.3 gpml ft. As the average sections in a pilot hole, before following through with a developed static water level is about 28 feet below land surface it is apparent well, because the lower one was missedin the driller's and sample that operating water levels are frequently close to the bottom of the log, and the upper one is describedas "fine." Cores would indicate well. whether development was justified. The City of New Castle has prospected unsuccessfully for the upper aquifer at 4th St. and Wilm The possibility of salt-water intrusion into the sands of the upper ington Ave. , and it maybe well to test the restof the middle aquifer aquifer exists because the intake area is crossed by the Chesapeake which is shown here at the water works before prospecting in other and Delaware Canal and the Delaware River, both of which contain places. brackish water. Two observation wells, Ea44-2 and Ea44-3, were completed in sands of the upper aquifer, on the south bank of the This composite log illustrates the difficulties in logging the sands canal near the Maryland State line (see pl , 7). Chlorides in these in the nonmarine Cretaceous sediments and emphasizes the need to wells are very low, even for natural ground water, and no evidence bring several techniques of modern science to bear in exploration in for salt-water intrusion was found. Rather, the head in the wells is this area. Even with careful and composite logging, the finding ratio 1 to 4 feet above sea level, and a positive gradient exists toward the may be less than 50 percent. canal during most phases of the tide cycle (Rasmussen and Beamer, 1956 ). Upper aquifer. --The upper aquifer is formed by the upper part of the nonmarine Cretaceous deposits and includes, in places, the Transitional sediments, Magothy formation sands of the Magothy formation, which rest unconformably on the nonmarine Cretaceous sediments. As mentioned in the last section, sands of the Magothy forma The upper aquifer consists of fine to medium, usually well-sort tion at places, are part of the upper aquifer. The Magothy forma ed, white and gray sands, and lenses of variegated silts and clays tion overlies the nonmarine Cretaceous sediments dis conformably, with red, gray, and white the predominant colors. These sedi and in like manner is overlain by the marine Cretaceous sediments. ments are of continental origin, and were deposited by rivers or in The logs of 40 wells show that it ranges in thickness from 2 to 58 estuaries. The sands of the upper aquifer are similar to those of feet and has an average thickness of 26 feet. However, some well the lower and middle aquifers, but slightly finer, or more silty, in logs show the Merchantville clay resting directly on the nonmarine general. The average description, a "fine to medium sand and silty Cretaceous sediments. sand", indicates that drillers will have trouble developing wells in 'v the upper aquifer in some places. Dry holes are a distinct possi": The Magothy formation consists of white, sugary, lignitic sand bility in the upper aquifer. On the optimistic side, however, several 115 114 intercalated with lead-gray clays containing abundant carbonaceous the Marshalltown formation of New Jersey. In Delaware, the Mer material. The Magothy formation is transitional; it is believed to chantville clay rests unconformably on the Magothy formation, or, represent lagoonal and paludal facies, with lateral changes in tex in some places, on the nonmarine Cretaceous sediments. It is over ture which are more gradual than those of the channel-fill and la lain gradationally by the Wenonah sand, although the thin zone of goon deposits of the nonmarine Cretaceous sediments. change in lithology may represent a diastem. Solution of the 3-point problem using three carefully cored and As the Merchantville is composed of dark blue to black, coarse correlated observation wells (Ea44-2, Ea44-3, and Eb3l-l) on the to very coarse, micaceous, glauconitic silt and very fine, micace south bank of the Chesapeake and Delaware Canal (see pl , 7) gave ous, glauconitic sand, the name Merchantville clay is a misnomer, a strike of N 68 0 E and a dip of 65 feet per mile to the south, for and it is preferable to refer to it as the Merchantville formation, as the top of the Magothy formation (Rasmussen and Beamer, 1956). proposed by Groot, Organist, and Richards (1954, p. 23). Possibly because the soft grains of glauconite are easily crushed into a slick, Water levels in 6 wells in the Magothy formation ranged from clay-like mass, drillers and geologists alike have regarded this for 12 to 74 feet below land surface and averaged 35.5 feet below land mation as a clay, although in undisturbed texture, it is a silty very surface. This is a lower average depth to water than for any other fine sand. formation in northern Delaware. However, 6 wells are not anade quate sample. The fact that coarse silt and very fine sand predominate in the Merchantville clay is hydrologically important, because, although Yields of 4 wells in the Magothy formation were reported to be these sediments do not yield water to wells, they are not quite.im 11. 3, 40, 100, and 108 gpm, respectively, and their specific capac pervious, and probably are capable of transmitting some water to ities averaged 1. 3 gpml ft. other formations under the proper hydrologic conditions. Thus, the upper aquifer may receive recharge not only from its intake area An ob s e rv attcn well, Eb3l-l, (see pI. 7) drilled near Summit beneath the Pleistocene sands and gravels, but also through the Mer Bridge on the south bank of the C 8< D Canal showed no contamina chantville clay. If this additional recharge takes place, the upper tion from salt water, although the Magothy formation crops out on aquifer may well have a greater water-producing capability than the sides and crosses the bottom of the brackish Canal is a 3-mile could be expected on the basis of the size of its intake area alone. stripwhich includes the well site. A positive gradientof 1 to 2 per However, the passage of water from the Pleistocene sands through cent (depending on the tidal stage) toward the Canal, is shown by the Merchantville clay to the upper aquifer mayalso enhance the po water levels in this well [Raarrrus aenaand Beamer, 1956). tential danger of salt-water encroachment into the deeper sands where salt- or brackish-water invasion occurs in the Pleistocene. Marine sediments The presence of glauconite and marine fos sils described by Rich a rds] Groot, and others, 1954) indicates thatthe Merchantville sedi The marine sediments of the Cretaceous system are composed ments were deposited in a relatively shallow sea. Such a deposit of the Merchantville clay, the Wenonah sand, the undifferentiated differs markedly from a nonmarine deposit in that the former is much Mount Laurel sand and Navesink marl, and the Red Bank sand, allLate more homogeneous lithologically than the latter; consequently, Cretaceous in age. These formations are well exposed in the deep whereas the nonmarine Cretaceous sediments show great differences cuts of the Chesapeake and Delaware Canal, and are shown in of texture and color within short distances, the Merchantville clay cross section along the canal in plate 7. Their configuration be differs little in texture and color throughout northern Delaware. neath the cover of Pleistocene deposits is shown in the geologic map., This consistency pertains also to the other marine upper Cretaceous plate 3. This interpretation must be used with caution, because it formations described in this section. is based on control that is fairly detailed in the Delaware City area but is somewhat sparse in the area west of DuPont parkway (high The Merchantville clay crops out along the banks of the Chesa way 13). -peake and Delaware Canal in several places, and is particularly well exposed west of the Pennsylvania Railroad bridge. It is known The Merchantville clay, an aquiclude. --The Merchantville clay to underlie the Pleistocene series in the southeastern part of north of northern Delaware is--lithologically--the equivalent of the Mer ern Delaware, beneath much of the area occupied by the Tidewater chantville clay of New Jersey, but in time it is probably equivalent Oil Company, . as shown on the geologic map, plate 3. In 34 well to the combined Merchantville and Woodbury clays, and possibly logs which represent the complete section of Merchantville, resting 116 on the Magothy formation or upper aquifer. and overlain by the We- - Sediments beneath the coastal terraces The upland sediments are brown and reddish - brown gravelly sands and silts lying unconformably on the gabbroic materials. The upper four or five feet of these sediments usually consists of gray The origin of the surficial sediments and the topographic fea broWn laminated silt, with small amounts of sand and clay, and with tures associated with them have been the subject of controversy for some small quartz pebbles. Below this layer, a bed of subangular along time. They have been regarded as marine by some geologists, to rounded quartz pebbles is found in a matrix of light brown sand, particularly those who worked along the sea and bayshore; fluvial by silt, and clay. others, particularly geologists who worked in valleys; and both mar ine and fluvial by those who did their field work in border areas. Generally, the upland sediments are not more than 10 feet thick, Northern Delaware is inthat border area where probably river, est but in 6 wells which are developed in the thicker portions., the thick uarine, and marine processes have been at work. ness ranged from 18 feet to 86 feet (Bd23"l), and averaged 39 feet. All of the deposits have been related to the Pleistocene series, The upland sediments are confined to the Bd quadrangle, and deposits derived from river discharge (and possibly long - shore their areal extent is shown on the geologic map, plate 3. Except wash), that came off the great areas of ice debris 150 to 200 miles for one small area, the upland sediments are confined to the area north of northern Delaware, down the Delaware Valley from New of the gabbro complex north of Wilmington. The small exception is York and Pennsylvania, and along the shore from northern New a group of low hills northwest of Brandywine, just west of State high Jersey. way 202 near the Great Circle. Here the sediments mantle the Wissa hickon formation. This confinement of the sediments chiefly to the Miller (Bascom and Miller, 1920) mapped the Talbot formation plateau underlain by gabbro may be oViing to the more rapid weather in this area, on the Coastal Plain, below the 40-foot contour, and the ing and erosion of the metasedimentary area. The scattered occur Wicomico formation, from 40- to 100-foot contours, as interglacial renee of rounded pebbles on ridges and hills in the area of the Wissa marine deposits, formed during higher stands of the sea at a 40- and hickon formation may indicate a much greater extent of the upland 100-foot strand line (not shown on the geologic map, pl , 3). Bascom sediments in former times. (Bascom, Clark, and others, 1909) mapped gravelly sand outliers on the Piedmont in the vicinity of Claymont and Arden, as river terraces, Owing to their limited areal extent and thickness, the upland and designated them as part of the Pensauken formation of the Dela sediments are only of minor importance as a ground-water reservoir. ware Valley and the New Jersey Coastal Plain (see geologic map, pl , In four wells in which water levels were obtained, the measured or 3). reported water level was 4, 14, 20, and 24 feet below land surface, respectively, at the time the well was visited. In subsurface mapping for this report, Rasmussen has developed plate 8, the configuration of the base ofthe Pleistocene series, which Pliocene(?) series, Bryn Mawr(?) gravel, a minor aquifer. - shows four channels, designatedH, M, L, and W (representing high-, The upland sediments were originally mapped by Bascom (Bascom mrd«, and low-level, and Wisconsin, the late Pleistocene stage). and Stose, 1932), and were correlated with the Bryn Mawr gravel These are presumed to have been carved during various stages of of Pennsylvania. Ward (1956) remapped these sediments in north the Pleistocene epoch, by earlier courses of the Delaware River and ern Delaware during the field season of 1955, and concluded that they its tributaries. The channels are completely filled in some places, were slightly more extensive than Bascom had outlined. and partially filled in others, with deposits of gravel, sand, silt, and clay, in at least three alternating cycles. A wordof caution must be given about the validity and use of this lZO '" lZl map. It is a preliminary interpretation, based on logs of wells and ness than proper areal representation would show. test holes, and electrical resistivity measurements (Spicer, McCul lough, and Mack. 1955), as indicated by symbols on the map. Inthe The Pleistocene sands and gravels in northern Delaware are Delaware City, in the New Castle, in the Farnhurst, and in the New characterized by favorable hydrologic properties: relatively high ark areas, this interpreta.tion is based upon fairly dense control. coefficients of transmissibility, in the range from 10,000 to 140,000 Elsewhere the control is. fair to sparse, and the locations of the gpd per ft. (Rasmussen, 1955, p. 64); and "water - table "coeffi channels are highly conjectural. Prospecting across a 1- to 3-mile cients of storage, in the range from 0.01 to .20. However, there strip may be necessary in some places to delineate the old valley are several factors limiting the yields of wells in the Pleistocene courses. aquifers. These factors are: The geologic significance of these channels is that they represent 1. The saturated thickness of the aquifers is small in many plac periods of lowered sea level, with river excavation at times and in es, particularly so in the vicinity of the Fall Line. The average places more than 100 feet below present level. These times of low water level in the Pleistocene series, determined from measure ered sea level presumably coincided with extensive development of ments in 348 wells visited during the period of this investigation the continental ice masses, which advanced and retreated four times. was 17 feet below land surface. Comparison ofthis with the aver River alluviation, chiefly gravel and sand, occurred as the sealevel age thickness of 36 feet (most of the wells were used in both aver rose and the ice melted back, until the valleys were drowned, and ages), indicates an average saturated thickness of only 19 feet, estuarine deposits, chiefly silt and clay, were laid down. Finally, much too low for high capacity wells, considering that under when the sea level rose to heights above the present, a strand line water-table conditions, dewatering of the aquifer occurs. was formed at 25 to 40 feet, and perhaps higher, and estuarine or marine sediments were deposited. 2. Even where saturated thickness is great enough to allow con siderable drawdown, the yields of wells are limited by the size The economic significance ofthese channels is that they are the of the recharge area and the rate of infiltration into the ground. lines along which high - capacity wells may be developed and large For example, at Newark the north basin had an infiltration area quantities of ground water may be taken. In places gravel and sand in 1952 of only 1. 6 square miles. It was calculated that even pits appear to be on the channel trends. under optimum spacing of wells and adjustment of pumping rates, the enlarged area of influence could not exceed 2. 5 square miles In the interchannel areas, the Pleistocene series is absent or (Groot and Rasmussen. 1954, p. 63-64). thin, and only small-capacity, domestic-type wells top the deposits. Some idea of the ranges in thickness of the Pleistocene series can 3. In the vicinity of the Delaware River, static water levels in be seen in the geologic cross sections, plates 4 and 7. wells in the Pleistocene are sometimes only a few feet above sea level; pumping water levels may drop below sea level and salt Pleistocene series, an important aquifer system. --Sediments water encroaclunent may occur. of the Pleistocene series overlie the Cretaceous deposits of the Coastal Plain unconformably. They consist of buff, light brown, Well Ecl3-11, 126 feet deep, developed in the sedimentary fill and rust-brown, pebbly, fine to coarse sands and, in some places, of a Pleistocene channel, has the highest yield of any well in northern of gray silts. A gravel bed, of one to four feet in thickness, usually Delaware, 1050 gpm. Well Dc52-29, also in the Pleistocene series, marks the base of the Pleistocene sediments. In a few localities has the highest specific capacity, 56.5 gpm/ft. The yields of 49 peat bogs have been observed, particularly in the north bank of the wells tapping the Pleistocene series in northern Delaware ranged Chesapeake and Delaware Canal east of the Pennsylvania Railroad from 5.0 gpm to 1,050 gpm and averaged 260.5 gpm, higher than bridge. the average of any other aquifer (see table 14). The specific capac ities of 27 wells tapping the Pleistocene series in northern Delaware The thickness of the Pleistocene series in northern Delaware ranged from 0.6 to 56.5 gpd/ft and had an average of 19. 1 gpm/ft, based on logs of 376 wells averages 36 feet and ranges from 2 feet higher by far than the average for any other formation (see table (Dc54-3, Eel5-l3, and Ed2l-4) to 126 feet (Eel3-6, although only a 15). few logs show more than 100 feet (115 feet in CeSS-I; 114 feet in Cd43-3; and 106 feet in Cd43-4). Although the spacing of these wells The greater yields in the Pleistocene series are related to three is not at all uniform, and a good statistical representation cannotbe of the four Pleistocene channels delineated on the map, plate 8. The claimed, nevertheless, the relatively large number of well logs sug fourth channel, labeled W, is confined to the Delaware River, and gests a reasonable approximation, perhaps somewhat larger in thick- consequently is notused for ground watei. The wells and well pos- lZZ 1Z3 sibilities of the channels are discussed briefly in the paragraphs it falls on lower ground than the middle-level channel, and because which follow. its base may be somewhat lower, that is, to about 120 feet below modern sea level, although good evidence for this is not confirmed. The channel identified by the symbol H is called the high-level The large galleries (Cd52-l, -2, and -3, 450 gpm) developed in the channel, because it underlies some of the highest topography of the Pleistocene deposits at the Water Works of the City of New Castle Coastal Plain (80 feet above s.ea level), and because its base ranges are in the margin of this channel, and the well of the Richmond Radia from 20 feet above sea level beneath the State Hospital at Farnhurst tor Co., Cd52-l2, reported to yield 700 gpm, is in it. Wells of the to about sea level at the Canal near the Maryland State line (see Atlas Powder Co; , no longer in use, Cd43-2, -6, and -7, had test cross section, pI. 7). Wells at the State Hospital (Cd4l-l, -2, and yields of 300, 600, and·4l0 gpm, respectively, and are in this channel. -3) and at Wilmington Manor (Cc55-b, -7) are the largest wells in this filled channel, and they have only moderate yields (215, 95, 230, The evidence appear s to indicate that the low-level channel pass 134, and 100 gpm, respectively). The channel is fairly well drained es off into the Delaware River at New Castle, and also above the by gulleys and gravel pits and the static water level has been lower mouth of the Christina River. Therefore the land area, along which ed to the point where the saturated thickness is small and restricts this channel will yield ground water, is a narrow border to the Dela the yield of wells. ware River between New Castle and Atlas Point. The opportunity for developing one or two additional high capacity wells in this strip The channel course in the sou the rn end, in the vicinity of Lums is fairly good. However, the possibility of salt-water encroachment Millpond, is somewhat conjectural. However, in view of the im must be considered. pressive channel-fill deposits shown in outcrop along the Chesapeake and Delaware Canal (see pl , 7), indicative of a major valley, this The Delaware River now covers most of the two former channels, connection of the high-level channel was carried from Wrangle Hill , znarked Land W on plate 8. These channels were discovered in the the last area of good control, to the Canal. If this questionable geologic section at the Memorial Bridge (see fig. 20, Marine and course be proved by later drilling, it means that a major southward Rasmussen, 1955), and their surface manifestation is shown by the flowing river passed from the Delaware basin to the Chesapeake soundings given on charts of the U. S. Coast and Geodetic Survey. basin, probably during the early Pleistocene time, with a gradient of The L channel is more completely filled than the W channel. about 1. 4 feet per mile. Better well sites may be available in the southern (conjectural) part of this channel than in the northern part, One major cros s channel of the Pleisto cene fill is shown on plate because the land is not as well drained there, and the saturated thick 8, corning southeasterly from Newark toward Del.awa.r e City. It has ness would be greater. been marked H?, to indicate that it probably is a tributary to the high-level channel. The channel is bounded by +40 foot contour lines, The channel identified by the symbol M, meaning "middle -level" and the lowest altitudes of the base of the Pleistocene series are a is the channel along which high-capacity wells and some large gravel few feet above modern sea level. Moderate-capacity wells are devel pits have been developed. The wells now used by the Atlas Point oped in this channel at Newark (187 gpm from Ca55-3; 304 gpmfrom plant; the wells of the Artesian Water Co.at Swanwyck, at Wilming 'Ca55-5; and 166 gpm from Cb5l-2). An additional well field, the ton Manor Gardens, at Llangollen Estates, and at Midvale; and the Newark south basin, has been located along this channel (Gr-oot and wells at the Tidewater refinery are all in this channel. The yields Rasmussen, 1954, p. 46, 84) and other wells probably will be drill of these wells range from 350 to 1,050 gpm. ed in this channel in the future. The lowest altitudes recorded in wells for the base of this chan The present valley of the Christina River also shows on the map nel are 82 feet below sea level at the north end (Cd43-5) and 90.5 as a possible Pleistocene channel. Well-log data in this valley is feet below sea level near Delaware City (Ec13-6). Control on this meager, and any establishment of it as a channel during the Pleisto channel loses accuracy from Llangollen Estates to Red Lion Creek, cene will depend upon obtaining better control. and from Dragon Creek to the Canal. These are areas in which test drilling is needed, and in which large. capacity wells may yet be The geologist is naturally interested in how the sequence of developed. It is still a matter of hypothesis whether this filled chan Pleistocene valleys in northern Delaware conforms to regional geol nel continues to the southwest beyond the Canal, or makes a right. ogic history. Owing to the present deficiency of detailed knowledge angle bend to the southeast, somewhere near Dragon Creek, paral about the valley system, the sediments themselves, and the associ leling the present river. ated topographic features, not to mention the complete lack of fossils in the Pleistocene of northern Delaware, it is premature to do more The symbol L identifies the low-level channel, so called because than suggeet a relationship with the ice at.es and interglacial stages. lZ4 US However, little progress is made without some speculation, even if easily weathered, do the valleys widen sufficiently to give some it serves merely as a working hypothesis, or as a straw man for semblance of a flood plain. One such place is on White Clay Creek others to pummel with the truth. .All of the correlative formations about Z miles north of Newark. mentioned are part of the Columbia group. The alluvium functions as an aquifer, in conjunction with the Therefore, it is suggested that the high-level valley, H. may have underlying rock, but its role is obscure. In the Red Clay Creek val been carved during the first glacial stage, that is. the Nebraskan, ley, the Hercules Powder Co. (see Bc52-2, -8, -9, -10, -13, -14, and may have received its principal filling with detritus during the -15, -17, -18, -19, -ZO, and -Z3), and the Haveg Corp. (seeCc2Z succeeding interglacial stage, the Aftonian. Thus it may hold the 5), derive fairly large quantities of ground water from rock wells in fluvial fill correlative with the Bridgeton formation of New Jersey, gabbro. The yields presumably are sustained by recharge from the and possibly a veneer of marine detritus correlative with the Coharie, creek, filtering through the alluvium to the rock crevice-type reser Sunderland, and Wicomico formations of the Atlantic Coastal Plain voir. terraces, although no evidence of marine sedimentation has been found. Recent series. --The alluvium is part of the Recent series. which began to accumulate as the sea level rose and the continental ice The middle valley, M, may have been carved during the Kansan masses receded a few thousand years ago. No sharp lithologic bound glaciation, and may have received its principal fill during the suc ary exists between the Pleistocene deposits and the Recent series. ceeding Yarmouth interglacial stage. In fluvial material, its con In the well logs, the man-made fill, the soil zone (1 to 3 feet thick). tained deposits may be correlative to the Pensauken formation of and the very loose muds along the tidal rivers have been assigned to New Jersey ( see Campbell and Bascom, 1933). In estuarine or the Recent series. marine detritus, it probably holds material equivalent to the Wico mico, Penholoway, and possibly the Talbot formations. The low-level valley, L, was probably carved during the Ilfmodan glaciation. Whether the channel was the earlier Delaware River, or whether the earlier Delaware River passed through Gloucester and Salem Counties, New Jersey, to the east, and this was the channel of the earlier Schuylkill River, confluent with the Christina River system, cannot be established. In atl.y event, the interglacial estu arine or marine detritus it holds maybe equivalent to the Cape May formation of New Jersey, the Talbot formation of Maryland. and the Pamlico formation of the Atlantic Coastal Plain, presumably formed during the Sangamon interglacial stage. The final drowned valley, the W channel. probably was carved during the Wisconsin glaciation. It may be filled only with sands and gravel of late Wisconsin age. and mud of Recent age . .Alluvium, a minor aquifer The alluvium in northern Delaware consists of river-laid sand, silt, and clay in the valleys of the modern streams. The thickness of the alluvial fill is somewhat conjectural because well records are not available, bit it is presumed to be variable, ranging from a few inches, on the margins of the "flood plains" to a few feet, or a few tens of feet in the filled channel. The phrase "flood plain" is placed in quotation marks to Signify that flood plains as such are a vague feature of the stream valleys in northern Delaware. In only a few places in the Piedmont, where the rock is somewhat softer or more 1Z7 lZ6 QUALITY OF WATER For example, iron may be a nuisance in concentrations more than 0.3 ppm and a serious problem in concentrations more than 1.0 ppm. At 20 ppm it is nearly intolerable for many uses of water, but The quality of water determines the treatment required before it can almost be completely removed by treatment at moderate the water can be used. Water of objectionable quality can be rend cost. Sodium, on the other hand, up to 30 or 40 ppm, is unnoticeable ered usable by treatment, but for many waters the treatment is so for most uses of water and several hundred parts per million is tol costly that other sources are sought. The disposal of polluted water erable for some uses. Sodium can be removed only by costly treat without injuring usable water sources or ruining acres of land, is ment, through base exchange or distillation. one of the great problems of modern industry. Control of the qual ity of water is a major concern for the people of all areas. . Mos~of the substance dissolved in wate r e"xist as electrically charged particles,_ called-ions. These are either metallic (or basic) The quality of water is related to the mineral matter dissolved ions, such as sodium [Na}, calcium (Ca), and iron (Fe), or non from the ground, the substances contributed by industrial, munic meta~lic(or acidic) ions, such as chloride (Cl), sulfate (S04)' and ipal, and agricultural wastes, and the intrusion of salt water from fluor-ide (F). The concentration of hydrogen ion (H+) is significant the sea. The term pollution, as used in this report. will apply to as anIndex of the corrosiveness of water. The importance of other organic waste products in water, and the term contamination will constituents of water is described in the following summary para- apply to the incursion of mineral salts, acids or alkalis, from the graphs. . sea or other source. The problems of pollution are not discussed in this report. They are the concern of the State Board of Health Color and the Water Pollution Control Commission, and are being con sidered in their reports [Kaplovaky , 1950-1955, 1952, 1954). Color in water is due to dissolved substances of either vegetable The mineral quality of the water in the northern Delaware area, or mineral origin. . both in its natural and in any contaminated state, is the subject of discussion in this section. The significance of water quality has Humus, . peat, and vegetation, 'particularly the algae group of been discus sed onp, 32. The general principles of water chemistry plants that commonly are distributed in swamp water, often will are summarized in the following subsection. Saline water as a water giv~such water a color value as great as 300. Municipal andinany source is described, for the Delaware River, the Chesapeake and industrial wastes, such as those discharged from chemical plants Delaware Canal. and the ee tua.r ie s , , The qualities of the ground or pulp and paper mills, contribute to the color. Color in water is wate r s are briefly described, as are the problems of intrusion. disadvantageous in many enterprises such as ice rnakdrig; beverage, photographic, laundry, and textile industries. - The data on which this quality - of - water section is based are meager from the viewpoint of the hydrologist. The paucity of ade Hydrogen-Ion Concentration (PH) quate analytical data is attributable to the fact that there has been no continuing program of chemical analyses of water. The Irrterrai tytof acidity or alkalinity of a water,' as indicated by GENERAL PRINCIPLES OF WATER QUALITY the pH value, is of importance in the determination of' corrosive properties of water and the proper treatmentfor coagulation atwater By E. F. McCarren and N. H. Beamer treatment plants.' The pHof water is expressedas the negative log arithm of the number of moles of ionized hydrogen pe r Hte r of water. A ne ut r al water has a pH of 7. O. The pH of most natural waters The chemistry of most natural surface and ground waters is a normally ranges between 6.0 and 8. O. Some alkaline waters have chemistry of small quantities. The dissolved and suapend ed corr pHvalues greater than 8.0 and waters containing free mineral acid stituents are reported in parts per million (ppm). A part per mil may have values less than 4. 5. The discharges of strong add or lion is a unit weight of a constituent in a .million unit weights of alkaline wastes will influence the pH value of a river or stream into water. Standard methods of analysis, or adaptations thereof were Which they are released. The pHofocean water isgenerallybetween used in making the analyses for this report. 7. 5 and 8.. 4 whereas fresh waters may have a wider pH range as a result of different conditions of soil and vegetation of the wate-r shed The range of dissolved substances, inparts per million (ppm). andindustriallUldmunicipal discharges. The pHof water is critical and particularly, the tolerable range, is distinct for each substance. -to thelife otoysters whfch g row beat Ine aldne waters that are slightJy lZ8 IZ9 alkaline. The life of the oyster is endangered when the pH value of S. Public Health Service recommends that the concentration of iron the water drops below 6.5. and manganese together in public water supplies should not exceed 0.3 ppm. Specific Conductance (micromhos at 25 0C) Iron (Fe) The specific conductance of a water is a measure of its ability to conduct a current of electricity. It varies with the concentration Iron is dissolved from the soil and rocks and is usually found in in ground in can ~nddegree .o~ionization of the different minerals in solution. Changes greater concentrations water than surface water. It In the spe cifi c conductance of a water reveal changes in the coricerr be dissolved from pipes of.a water-supply system. Natural waters t~a.tionor relative proportion of the minerals dissolved in it. Spe may be polluted by iron-bearing wastes from industrial plants. Or cifi c conductance may be used as an indicating factor for general dinarily the concentration of iron in natural surface waters is less classification of waters and has been widely used as one criterion than O. 1 ppm. Large amounts of iron, greater than O. 3 ppm for in the alassification of irrigation waters. The approximate dis solved household and O. 1 ppm for industrial use, are considered undesir solids in parts per million may be obtained by multiplying specific able because of a condition that is commonly referred to as "red conductance in micromhos by the factor O. 6. water." This is caused by precipitation of iron when it is oxidized; it causes stains in sinks, washbasins, and bathtubs. Delicate fab Silica (Si0 rics are damaged with stains when washed with water of high iron 2) concentration. The dyeing, tanning, and textile industries, bottling companies, paper manufacturers, and others require water that is virtually free of iron. Table 18 summarizes the tolerances for iron Silica is found in both surface and ground water but is rno r e pre valent in ground water. The usual range of its concentration is from in water used for certain industrial processes. 1 to 60 ppm. However, it sometimes does exceed 60 ppm, but very Calcium (Ca) rare.ly: The silica in water is dissolved from sand, quartz, feldspar, kaofinfte , and other minerals. Silica in water may contribute to boiler scale and to boiler failure, and to deposits on steam-turbine Calcium salts among the predominant constituents of water. blades. are Calcium and magnesium are generally considered together because of their similar effects upon the use of water. Hardness in water Aluminumo(Al) is caused primarily by calcium and magnesium which, among other disadvantages, cause boiler scale. Hard water used for such house hold chores as washing, bathing and laundering requires large a Aluminum is not regularly determined in the analyses of water. mounts of soap to produce a lather, because the calcium and mag In most natural waters the aluminum concentration is so small that nesium combine with the fatty acids of the soap to form a sticky it is of little significance in evaluating water for industrial use. How ever, significant quantities of aluminum are sometimes found in acid curd, before the lather forms. waters and in waste wat.er from water-treatment plants. Aluminum Calcium may be discharged into rivers and streams from SfN' in water has been reported to be objectionable to certain industries age and different types ofindustrial wastes. Galcium is Clissolvedfrom such as those manufacturing rayon, paper, and textiles. ' practically all rocks, particularly limestone, dolomite, and gypsum. Most waters from granite contain less than 10 parts per million of Manganese (Mn) calcium; many waters from limestone contain from 30 to 70 parts; and waters that leach deposits of gypsum may contain more than 100 Manganese in water often accompanies iron, and like iron is ppm. an undesirable constituent because it may cause discoloration and Magnesium (Mg) stains. Manganese deposited from solution can clog pipes and valves. Ordinarily the concentration ofmanganese in natural surface waters willnotbe in excess of a few tenths part per million, but the concen Like calcium, magnesium is an abundant element of the earth's tration in ground water may be several times greater. Industries crust. Generally, the salts of magnesium are readi\:(soluble. Water such textile manufacturing, dyeing, food distilling as processing, that contains much magnesium chloride is likely to be corrosive arid and brewing have found manganese in water objectionable. The U. 131 130 particularly damaging to steam boilers. The magnesium in soft Table 18.--Threshold values for iron in process and waters may amount to only 1 or 2 parts per million, but in waters coo ling waters. in areas of dolomitic rocks it may exceed ~Oto 50 parts per million. The U. S. Public Health Service recommends that the concentration (California Water Pollution Control Board, 1952 of magnesium in drinking water sho.uld not exceed 125 ppm. ':!atcr Quality Criteria: Sh'FCB Pub. 3, p. 277) Sodium and Potassium (Na and K) Industrial Use Parts per million Sodium and potassium are dissolved from practically all rocks, Baking •••••••• 0.2 but usually make up only a small part of the dissolved mineral mat Bre~ling•••••••• 0.1 to 1.0 te r ; Potassium resembles sodium in many of its properties, and Carbonated Beverages •••• 0.1 to 0.2 potassium salts can be substituted for sodium salts in many indua Cooling ~-Jater•••••••• .' • 0.5 trial applications. Moderate quantities of these constituents cause Confectionary •••• 0.2 little trouble, but waters that carry more than 50 ppm of sodium Electroplating ••••• Traces plus potassium may cause foaming in boilers. The amount of sodium Food Canning and Freezing • 0.2 in water is a factor for determining its suitability for irrigation. Food Equipment Washing •••• 0.2 Exces sive concentrations of sodium cause soil colloids to swell and Food Processing, general 0.2 to 0.3 close the pores of the soil, thereby reducing the soil's permeability Ice Manufacturing • •• ••• 0.03 to 0.2 to water and air. Laundering •••• •••• 0.2 Oil~WellFlooding • •••• 0.1 Bicarbonate (HC03) . Plastics Manufacturing •••••• 0.02 Pulp and Paper Making Groundwood Pulp •••• 0.3 The presence of bicarbonate in natural waters is largely due to Soda Pulp •••• 0.1 the action of carbon dioxide which enables the water to dissolve Kraft Pulp, Bleached. 0.2 carbonates of calcium and magnesium. Bicarbonate can be added Kraft Pulp, Unbleached •••••• 1.0 to water by decornpoai'tion of oz-gani c material and by wastes from Fine Paper Pulp 0.1 industrial processes. Excessive araounts of bicarbonates tend to Rayon Manufacturing 0.0 to 0.05 form carbonate scale at high temperature. Sugar Making •••• 0.1 Tanning Processes ••• •• .. • • 0.1 to 2.0 Carbonate (C03) Textile Manufacturing ••••• .'. • 0.1 to 1.0 Generally, carbonate is not present in natural surface waters, traced to industrial wastes from tanneries, sulfate pulp mills and but it may occur in some ground waters. Excessive carbonate in other manufacturing plants whose operations require the use of water has been ~onsideredparticularly objectionable by the carbon sulfates or sulphuric acid. ated-beverage industry, brewers, and ice manufacturers. The U. S. Pub.lic Health Service standards (1946) sets no' limit for concen Chloride (Cl) trations of carbonate in untreated water, but in chemically treated waters the standard carbonate alkalinity should not exceed 120 ppm. Chloride is present in most natural waters and uncontaminated Sulfate (S04) surface water will usually contain a few parts per million. Tidal rivers and streams may have high concentrations because of en croachment of sea water. Chlorides find their way to streams from Sulfate is found in natural waters as a result of the solution of cultivated fields. dissolved rock materials, and from industrial wast e sodium sulfate and gypsum in rock and soil. It may be formed also and sewage, Chloride catalyzes corrosion of boilers, pipes' and fit f'r om the oxidation of sulfide, sulfite and thiosulfate. Iron pyrite, tdngn , Concentrations of chloride as low as 20 ppm have been re FeS2' through the action 6f water and oxygen of the air, is the source ported to b~corrosiil'e.The U. S. 'Puhlic Health Service recom- of sulfate found in acid mine waters. Sulfate 'may" sometime s be 133 13Z '.'J. mends that the concentration of chloride should not exceed 250 ppm Table 19.--Limiting concentrations of dissolved solids in drinking water. for industrial waters. Fluoride (F) Indust:dal Use Concentration (ppm) Concentrations of fluoride in surface waters generally does not Paper lIanufacturing exceed O. 5 ppm but greater concentrations are often found in ground Grounduood Papers 500 waters. Excessive concentrations cause the dental defect known as Fine I'apers ••• 200 mottled enamel, if the water is used for drinking by children during Kraft Taper, Unbleached. 500 calcification of the teeth. This condition becomes more noticeable Kraft Paper, Bleached. 300 as the quantity of fluoride in water increases above 1 part per mil Soda and Sulfate Pulp •• 250 lion. However, the incidence of dental caries (decay of teeth) is de creased by quantities of flllOride that are not sufficient to cause Pulp Faper and Faperboard mottled enamel (Smith, Cammack, and Foster, 1936). Fordrinking High Grade Products • 75 - 80 purposes, or food or beverage manufacture, water should not contain Lower Grade Products 150 - 200 more than 1. 5 ppm of fluoride. Confectionary ••••• 100 Nitrate (N03 ) Ice RmJ H8.ter ••••• 170 - 35rj!/ Plastics, Clear, Uncolored 200 Food l:-roducts 850 Nitrate in water is considered a final oxidation product of nitro Dairy .....•••• G50 genous substances from sewage or other organic material. How Bre~"ing,Light. ••• 500 ever, industrial wastes from explosives and fertilizer plants may Brewing, Dark •• 1000 contain appreciable quantities of nitrate salts. A nitrate concen Breuing and Distilling 800 tration in excess -of 50 ppm (as N03) in water consumed by infants Carbonated Beverages 055 has been directly associated with methemoglobinemia, a condition Ha_shing of Utensils • 350 in which the surface of the body of an infant becomelil blue (Waring. Boiler Feed Water ••• 50 - 300cJ!./ 1951). Unpolluted surface waters seltiomhave more than afewparts per million of nitrate. Nitrate may reach abnormal concentration in percolating ground water in areas under cultivation where nitrate ~/ Water with concentrations as much as 1300 ppm has fertilizers have been added to the soil. Leachings of cesspools also been used successfully. Water Quality Criteria can be a source of nitrate contamination. The presence of nitrate California, Water Pollution Control Board, 1952, in water is objectionable in dyeing fine fabrics and also in the brew p. 246. ery industry. £/ Varies according to pressure of boiler. Dissolved Solids they may have on color or taste of the water. Table 19 gives the Lirr.Itfng concentration of dissolved solids for industrial waters. The reported dissolved solids (the residue of evaporation) con sists mainly of the dissolved mineral constituents in the water. It Hardness may also contain Some organic matter and water of crystallization. Waters with less than 500 ppm of dissolved solids are usually sat isfactory for domestic and most industrial uses. Water with more Hardness of water is most commonly recognized by the amount than 1,000 ppm o(dissolved solids is likely to be unsuitable for many of soap required to form a lather in washing. Carbonate hardness uses. The concentration of mineral constituents in water can be in water caused by calcium and magnesium bicarbonate, may be re lessened by dilution or Inc re aaed by discharges of industrial waste moved by boiling the water, or by treatment with lime. Noncarbon and by drainage from irrigated land. High concentration of dissolved ate hardness caused by calcium and magnesium salts cannot be re solids are obje ctionable because of the total salt effe ct and the effect moved byboiling norby Hmealona, but can be reduced by lime-soda 134 135 ash treatm.entor r ernovedby cation exchange r s, A water with non Table 20.--Maximum hardness for various industrial carbonate hardness generallyform.s a harder scale on boilers than processes. a water with only carbonate hardness. There is no difference be tween these two types of hardness in relation to the am.ount of soap (California Water Pollution Control Board, 1952, required to m.ake a lather. Water Quality Criteria: SWPCBPub. 3, p. 267) Perhaps no other characteristic of water has received m.ore con Industrial Use ppm sideration than hardness. Hardness in water is caused alm.ost en tirely by com.pounds of calcium. and m.agnesium. r e s'ult'ing from. the Boiler Feed Water contact of the water with soil and rocks. Hard waters m.ost frequent at 0 - 150 psi. • 30 ly are associated with deposits of lim.estone, gypsum., and dolom.ite. at 150 - 250 psi 40 The concentration of .calcium. and m.agnesium. m.ore than any other at 250 - 400 psi • ••• 10 constituents affects the value of waters used for industrial purposes. over 400 psi. • .• 2 Hard water deposits scale in boilers, piping system.s, engine jackets Brewing ...• •.•• 200 - 300 and is particularly objectionable to such industries as textile finish Carbonated Beverages 200 - 250 ing, dyeing, canning, ice m.anufacture, rayon m.anufacture, laun Cooling 50 dries, photography, paper m.anufacturing, and m.any others. Table Food Canning and FreezinB 20 surn.m.arizes the available literature on tolerance of hardness in General ••••• 50 - 85 industrial waters. Legumes • • • • • • • • • 25 - 75 Fruits and Vegetables 100 - 200 Total Acidity Peas •.• •••••• 200 - 400 Food Equipment Washine • 10 Food ProcessinB, General 10 - 250 The total acidity of a natural water represents the content of Ice ~mnufacture •••• 70 - 72 carbon dioxide, m.ineral acids and salts -- especially sulfates of iron Laundering •••••• o - 50 and alum.inum.--thathydrolyze to give hydrogen ions. Acid waters Pulp and Paper Making are very corrosive and generally contain excessive am.ounts of ob Groundwood Pulp •• 200 jectionable constituents, such as iron, alum.inum. and m.anganese. Soda Pulp •••••• 100 Acidity in surface or ground waters 'can be caused by carbon diox Kraft Pulp, Bleached 100 ide, hum.ic acids extracted from. swam.ps or peat beds, or by indus Kraft Pulp, Unbleached 200 trial wastes. Fine Paper Pulp •• • 100 Rayon CHEMICAL QUALITY OF STREAMS Pukp Production •• 8 Cloth ~~nufactl1re• 55 By E. F. McCarren Steel Hanufacturing 50 Synthetic Rubber 50 'I'anning Analyses of sam.ples of water from. stream.s in northern Dela Beam House • • • • 513 ware indicate that the average quality of water generally is good. Tan House • 50 - 135 For industrial use, only m.oderate treatm.ent or none at all is re Tex t Ll.e IvI..anufacture •••• o - 50 quired. The chief salt in solution· is calcium. bicarbonate, which causes a m.oderate hardness in stream.s draining principally from. the Piedm.ont. Stream.s draining principally from. the Coastal Plain are low inhardness and in dissolved solids, exceptfor those stream.s affected by tides in the Delaware River or by pollution • . Daily sam.ples of Brandywine Creek have been collected and an alyzed since Novem.ber 1946, and chem.ical analyses have been pub lished (Beam.er, 1953, p, 74) for 14 m.onths in 1949 to 1951. Several sam.ples at selected locations from. Naam.an Creek, Shellpot Creek, 137 136 Brandywine Creek, Red Clay Creek, White Clay Creek, the Christina The average hardness of the four samples was 82 ppm, a hardness River, Big Elk Creek, and Red Lion Creek were collected and an greater than that of any other fresh-water streamin northern Dela alyzed in the preparation of this report. These chemical analyses ware. As denoted by the high pH of the samples, the stream can be are presented in table 21, and the discussion which follows is based characterized as more alkaline than other streams in northern Dela on them. ware. The sulfate content averaged 34 ppm and is higher than that for any other stream in northern Delaware. South Branch Naaman Creek at Arden The results of these analyses may indicate some chemical con tamination of the' water, inasmuch as the creek passes through an Naaman Creek is a small tributary of the Delaware River at the industrialized urban area. The results do not appear to indicate northern tip of Delaware. It has a drainage area of 13.7 square organic pollution, inasmuch as chloride and nitrate, two indices of miles; 7.2 square miles in Pennsylvania and 6.5 square miles in organic pollution, are low. In part, the conditions maybe natural- Delaware. The creek is used by the Arden Water Co. in the up Shellpot Creek drains an area of gabbro - crystalline rock which stream portion ofthe South Branch and by the Colorado Fuel and Iron weathers to alkaline products and yields hard-water runoff. How Co. in the lower portion just before it enters the Delaware River. ever, Naaman Creek above Arden drains similar rocks, and is of much better quality. A sample was taken on October 5 and on November 17, 1955, from the South Branch of Naaman Creek at Arden (drainage area a Brandywine Creek at Wilmington bove this point is 3.8 square miles, of which 1. 0 square mile is in Pennsylvania). Analysis of both samples indicated water of good quality. The specific conductance of the samples indicated a con The Brandywine Creek is tributary to the, Christina River just centration of dissolved solids in the range of 55 to 65 ppm (see table before the Christina joins the Delaware River and is the principal 21). source of water supply for the City of Wilmington. It has a total drainage area of 329 square miles and a drainage area of 314 square A sample also was taken of Naaman Creek from the bridge on miles above the sampling point. Route 13 in Claymont, where the creek is tidal in this reach. The analysis of this sample is discussed in the section on Saline Water The water ofthe Brandywine is of good quality, adaptable to pub P> 144. ' lic water supplies and most manufacturing uses with a minimum a. • mount of treatment. The quality of the water does not vary marked Christina River Basin lywith the change of seasons. The hardness of water from the Brandywine Creek for 1952-1953 was between 50 and 60 ppm. The Christina River and its tributaries drain an area of 568 Figure 23 shows the average specific conductance of Brandywine square miles. Brandywine Creek, Red Clay Creek, White Clay Creek at Wilmington for the period December 1946 to September 1950, Creek, and Shellpot Creek are the principal tributaries. The Chri and the average dissolved solids computed from conductance. The stina River flows into the Delaware River at Wilmington. maximum monthly average specific conductance was 260 micromhos, e:turi~gFebruary 1947. A similar high occurred in February 1948 Shellpot Creek at Wilmington at 254 micrornhos. However, February 1949 and 1950 were below average. A plausible explanation for this anomaly may be the re lease of waste products in larger-than-usual quantities during these Shellpot Creek has a drainage area of only 9.54 square miles, months of high average because it appears that the differences in chiefly in the city of Wilmington. Four water samples were taken conductance cannot be attributed to the differences in discharge of at a site in Wilmington (drainage area above this site, 7.46 square the stream. The computed average dissolved solids ranges from miles) were analyzed (see table 21). 78 ppm to 116 ppm, with a gross average of 92 ppm. In general, the water fromShellpot Creek was, on several counts, Figure 24 is a conductance-duration curve, for the calendar years the poorest water in quality from any of the surface streams in Del 1947, 1948, and 1949. For one percent of the time the specific con aware (exclusive of tidal water). The average specific conductance ductance equalled or exceeded 380 micrornhos, for 50 percent of the was 245 micrornhos, indicating average dissolved solids of about time the conductance was 146 micrornhos or less and for only 10 150 ppm, greater than that of any other sampled fresh-water stream. percentof the time did conductance equalor exceed 180micrornhos. 138 139 :; Table 21.--Chemica1 analyses of waters from streams in northern Delaware. o All samples collected in 1955 with the exception of one from Naaman Creek at Claymont. collected AUgust 25. 1954. Specific Chemical analyses in ppm Mean Temper- conduct- Sodium Bi- Su1- Ch1or- Ni- Total Non- Location Date dis- ature pH an~e (Na) carbo- fate ide trate hard- carbo- charge (microm- and nate (S04) (C1) (N03) ness nate hoS at Fotas- (HC03) as hard- 25 C) sium CaC03 ness (cfs) (Or) (K) South branch Naaman Creek at Arden, Del. Oct. 5 .65 56 6.6 92.3 5.1 25 6.4 8.0 5.8 32 12 Do Nov. 17 1.35 45 6.7 107 5.6 29 10 7.5 4.2 36 12 Naaman Creek, Route 13 at Claymont. Del. Aug. 25 3 86 7.6 2320 344 44 118 620 3.2 289 253 Shellpot Creek at Wilmington. Del. Aug. 5 .890 84 8.3 275 19 a 80 33 18 2.0 86 2 Do Aug. 26 1.61 73 8.8 243 14 a 45 36 12 3.1 83 41 Do Oct. 3 1.0 65 7.6 250 13 68 38 10 4.9 85 29 Do Nov. 17 1.6 47 8.4 212 12 a 52 28 11 1.8 75 15 Brandywine Creek at Wilmington, Del. Aug. 5 73.6 83 6.8 222 14 74 27 10 .7 72 11 Do Oct. 3 275 63 7.0 163 5.4 50 19 5 4.7 60 19 Do Oct. 28 257 51 8.1 201 9.4 72 23 8.0 4.0 77 18 Red Clay Creek at Woodda1e. Del. Aug. 10 12 73 6.7 348 30 88 33 35 3.1 92 20 Do Aug. 25 56.5 71 6.7 192 10 57 20 9 4.7 62 15 Do Oct. 3 34 63 6.7 I 197 11 57 17 14 4.7 64 17 Do Oct. 28 29.7 53.5 6.7 234 16 64 19 24 14 82 30 . White Clay Creek above Newark, Del. Aug. 10 13.5 74 7.1 189 8.2 78 13 6 2.4 70 6 Do Aug. 25 61.0 75 6.8 172 6.1 62 15 6 5.5 66 15 Do Sept. 28 54.2 62 7.6 160 4.0 60 13 4 5.3 64 15 Do Oct. 27 38~7 52 7.3 169 6.3 67 14 6.0 4.8 68 13 white Clay Creek below Newark, Del. Aug. 10 23 79 6.7 225 9.6 70 16 18 1.9 80 23 Do Aug. 25 90 69 6.6 199 7.9 58 16 14 5.2 71 23 Do Oct. 3 48.3 62 6.9 169 6.2 55; 13 9 5.2 62 17 Do Nov. 17 55 45 7.0 167 6.9 58 15 8,0 5.5 64 16 Mill Creek at Stanton, Del. Oct. 5 7.16 59 7.1 156 9.9 50 12 11 4.5 51 10 Do Nov. 17 7.86 42 7.7 151 7.3 55 13 '7.0 4.3 56 11 Christina River at Coochs Bridge, Del. Aug. 10 1,40 77 6.4 138 11 42 15 6 4.3 38 4 Do Aug. ,24 18 67 6.2 110 3.4 23 18 3 3.1 37 18 Do Sept. 27 2.66 62 6.6 105 4.6 27 10 4, 4.6 32 10 Do Nov. 17 18 45 6.8 124 11 38 13 6.0 '2.3 32 1 Big Elk Creek at Elk Mills, Md. Aug., 2 10.9 91 ,6.6 107 9.7 31 7.6 9 1.4 26 1 Do Au&. 24 72.0 71 6.6 102 2.8 29 10 4 .4 LO 37. 13 Do Sept. 27 40.4 64 6.7 101 5.4 24 9.6 6 4~6 30 10 Do Oct. 27 33.5- 53 7.5 104 7.0 31 8.0 6.0 3.7 30· 5 Red Lion Creek at Red Lion, Del. Oct. 5 1.4 63 6.1 86.2 6.9 14 12 8.0 4.7 24 13 Db Nov. 17 .90 44 6.8 95.6 5.3 20 13 8.0 2.8 32 16 a Shellpot Creek - Aug. 5 - Carbonate value 2 ppm. Do - Aug. 26 - do 12 ppm. Do - Nov. 17 - do 7 ppm. carbonate equivalent is included in the sum of anion equivalents of each sample. ~... ~ From these data it may be inferred that the concentration of dis solved solids was less than about 110 ppm 90 percent of the time. In general, periods of high conductance were of short duration and were fewer in number in 1948 and 1949 than in 1947. Thus, Computed averaoe Monthly averaoe specific conductance, whatever the cause of the high conductance, its influe~cediminish dissolved solids, in ppm In micromhos at 25° C ed through the 3-year period. N N N N N CD N N ~ CD o o o 0 ~ ~ s ~ 8 S o Three samples of the water- from Brandywine Creek at Wilming c.. t ,'t> 0 ton, taken August 5, October 3, and October 28, 1955, were analyz o I ? ~ ed. Each o.f these samples exceeded by 10-20 ppm the average total \ I hardness for the 3-year period. The specific conductance for the -, ~) samples collected August 5 and October 28 exceeded the average by ~""'" ~ ==-'::.:::::: 50-70 micrornhos. r. / CD., ~ iiiI::-::::::-~--- ~ ~ ,- lD ~~ ,/ r;.::::::'""'- Figure 25 shows the decrease in specific conductance, reflect ~ .. V ( :. ~ ~~ .... ~::::. ing the decrease in concentration of dissolved solids, with increas / ~ 1----_....- ingflow of the Brandywine Creek at Wilmington. Usually, when the T > ,I discharge is under 600 cis the range of specific conductance is be , I tween 130 and 190 micrornhos. When discharges exceed 1,600 cis /1~I, the specific conductance may fall below 100 micrornhos, but rarely , below 90 micrornhos. 1>1 I I 1,'\ I Wolman (1955, p, 19 and fig. 21), in his study of the natural l channel of Brandywine Creek, derived an equation for the suspended c.. , C solids at ~ilmington,and presented a sediment rating curve. ::I \ CD , K' 1\ 11 \ , ~ Red Clay Creek at Wooddale c.. \ 5. 'C \ \, ~ Red Clay Creek is tributary to White Clay Creek. At Wooddale, Delaware where the U. S. Geological Survey maintains a gaging !~~ ~iDiDiDiD station, the drainage area of Red Clay Creek is 47.0 square miles, I \ ~ agcti~""x \ ~f- 33. 3 of which \ square miles are in southeastern Pennsylvania. Chem \ J> ical analyses of Red Clay Creek at Wooddale were made of samples 1\ z J> collected August 10, August 25, October 3, and October 28, 1955. \ \ ~\ -i Hili! I I of- z The water of Red Clay Creek is usable for many purposes. How .. o \ ,\ I I ! () ~ ever, the quality as indicated by analysis of water taken during low ~ . \, 1\ ~ \ flow, (12 cis) on August 10 is less desirable. The specific conduc t- ...... 348 a z tance of micrornhos indicated concentration of dissolved solids o V I of more -than 200 ppm, and hardness was 92 ppm. :c J j Vi White Clay Creek o IV, CD ~ P " I \: i White Clay Creek is the second largest triDutary of the Christina River and has a drainage area of 62.4 square miles above the Del aware -Pennsylvania State line and a total drainage area of 162 square miles. The water of White Clay Creek is used as a supplementary 143 142 supply by consumers in several parts of New Castle County and by various industries along the banks of the creek in the Newark area. Above Newark Specific conductance, micromhol at 25° C (II (II ln1955, samples of water for chemical analyses. were taken from .C7lCD~~~~ ~g;~~ C7l CD o• o 0 o the .White Clay-' Creek above Newark on August 10 and 25, September 00000000000 28, and October 27. All samples had specific-conductance values less than 190 micromhos and hardness values of 70 ppm or less. For most municipal and industrial uses little chemical treatment of the water should be required •. b~,§CJI The mean discharge was 13.5 cis at the time the sample on August • ~~I~3 ::0; ~i ('i' 10 was taken. On August 25 the mean discharge was 61. 0 cis which "'- (II &~ was the highest discharge value recorded for the four samples. The C.., 1\ ~ - -(') results of the chemical analyses ofthese two samples indicated little a CD change in quality with the change in discharge. !.a (5 \ ~ ~: Below Newark i= g ~~cll C7l a _. .:3Q,. CD '\ -N 0 ~=. Four samples of water from the White Clay Creek below Newark, N CD(') ~:3' collected on August 10, August 25, September 3, and November 17, \ - CDC 1955, respectively, were an.;uyzed. The results of the analyses of \ 0 l8 these four samples indicate little or no distinguishing differences in • i! the quality of the water above or below Newark. As indicated by \ values for specific conductance, the water below Newarkhas a slight ly greater concentration of dis solved, solids. The water is generally \ of good quality, slightly hard, but suitable for most purposes. \ The differences in mean discharge at the time of the collection \ of the samples below Newark had little effect on the quality of the water. About a fourfold increase indischarge resulted in adecrease \ of only about 12 percent in specific conductance. The specific con ductance of the sample taken at the lowest flow was 225 micromhos. \. --. ~ Mill Creek at Stanton '- ...... "" ...... Mill Creek is tributary to White Clay Creek near its confluence with Red Clay Creek. Two water samples were taken at the old gag ing station site at Stanton, one on August 5, 1955, and the other on November 17, 1955. The mean discharges on these dates differed by about 10 percent; the chemical analyses, in the main, differed even less. The w.ater is suitable for most purposes; it is softer and has a lower concentration of dissolved solids than the water from White Clay Creek. 144 145 Christina River at Coochs Bridge The flow of the main branch of the Christina River is checked bySmalleys dam, where the Delaware Water Company treats several million gallons a day for industrial and municipal clistribution. Somewhat upstream from that site, at the gaging station at Coochs Bridge (drainage area 20. 5 square miles above the bridge), four samples were obtained and analyzed in 1955 (see table 21). The average daily discharge of the Christina River for a period 200 of 12 years is recorded as 26. 1 cfs , The four samples were taken at a time when the flow was less than average. On August 10, 1955, the discharge was 1. 40 ds and on August 25 and November 17, 1955, . the discharge was 18 cfa, The analyses of these samples indicate 180 that the water of the Christina River at Coochs Bridge is useable for . . most purposes. o . . .II) Nl60 . Small Stream Basins on the Coastal Plain o .. 2 . ~ The surface water from the Coastal Plain of northern Delaware :>140 \ is utilized in part by the water plant on the Christina Ri ver at Chris "i .\.. .. tiana. However, the other streams, Mill or Army Creek near New ,; . ... . c: Castle, Red Lion Creek, Dragon Creek, and the tributaries to the o . . Chesapeake and -Delaware Canal and to Chesapeake Bay, are flmall, s rac K ." c:" <, and potential storage is also small. However, if the analyses of the o ... . water at the Christiana plant and from Red Lion Creek are typical, ... the waters are of good quality, and'may eventually be utilized. ~IOO <. <, ! en ~ ~ Red Lion Creek at Red Lion . 80 Two analyses of samples taken on October 5 and November 17. 1955, from Red Lion Creek (see table 21), reveal a softwater rela tively low in dissolved solids, and having a pH less than 7. o 500 JSXlO 1,500 2.000 2,500 SALINE WATER Di&charll. (cf.1 Figure Z5. --Conductance rating curve, a plot of apeckfic conductance VB. discharge of Brandywine Creek at Wilmington, 1947 to 1949. As pointed out in the section on "Significance and Sources of Water" p, 31, saline surface water bounds half the perimeter of northern Delaware, and provides a source of water used for cool ing and washing, which in quantity outranks the premium fresh wa ters many times. In 1955, the people of Delaware were using more than 439 million gallons of water daily, and of this about 360 mgd came from the Delaware River and the tidal estuaries of the Chris tinaRiver and NaamanCreek, chieflyfor cooling purposes (see table 30). 147 146 The saline water is discussed first with respect to the major 0\ OONIt'l body, the Delaware River, then the tributary estuaries, and finally . • • • -:t • the Chesapeake and Delaware Canal, a tidal link with Chesapeake •• r-l .r-l'C"l • C"l C"l 0 • •• r-l • I' • -:t -:t 00 • Bay. . ·N '00 • III • ·. ··N. .. ·. ·. · III · . Delaware River · By E. F. McCarren NN •• N ·N 'NN .I'NN • It'llt'l •• It'l .It'l • C"l It'l It'l • • r-l It'l • 0\0\ •• 0'\ • 0\ 0\0\ .0\0\0\ r-l r-l •• r-l .r-l • • r-C r-C"'" • II r-lr-l ••I •I •II •III• From Hancock, New York, the Delaware River flows 326 miles C"l r-l •• r-l .-:t • C"l r-l ·,....,....,..... NN 'C"l .0 C"l • C"l C"l C"l • to the Atlantic Ocean and is the boundary between New York and 0\ 0\ • .-:t .0\0\0\ • r-l r-l • .0\ .....• 0\ • 0\ 0\ ,....,....,.... Pennsylvania, New Jersey and Pennsylvania. and New Jersey and •• r-l • r-l r-l · . Delaware. At its mouth the Delaware River has a drainage area of 12,765 square miles. .-:tC"l-:tN 0\ 0 \OO\NNIt'l ·. ., .. ·. . .. • r-l 0\ It'l r-l r-l·.C"l \0 0\ 00 1'00\0 It'l The discharge rate of the Delaware River varies seasonally, with • -:t It'l C"l It'l r-lC"l1t'l0 I' C"l C"l \0,0' • C"lU U U N 0\.. the maximum discharges in the late winter months and the minimum ·u r-l discharges in the late summer months. The average discharge at · · I'. Trenton for a 42-year period 1913-1955 was 11,930 cis. A flow - r-l the gaging 1942-1955 0\ duration curve for station at Trentonfor is pre It'l r-l sented in figure 26. This curve indicates the frequency of various -:t •• I' It'l ·• C"l'O\..r-l. .• flow rates, irrespective of the chronological sequence. For example, 0\ r-l ·.•• \0. 'C"l • ('f') ,.....,..... • ·00· • ex>"'" •• r-l r-l 0\ • C"l C"l \0 • the flow rate was at least 4,000 cis (2,585 mgd) during 81 percent r-l •• N • co · . of the time. · . ·.r-l ... ·. The quality of the water in the Delaware River, in the reach of . the river between Marcus Hook, Pa., and Reedy Point, Del., is .p..ttl more closely related to the streamflcSw at Marcus Hook than at Tren ·.· .p..• ttl · ...... ton, N. J.. which is located some 40 miles upstream from Marcus • t1l .,c• .r-! •.p..t1lp..ctS • ctS • Hook. Because of the tidal nature of the river, the discharge of the · .. Delaware Riverbelow Trentonis difficult to measure and therefore • Qj .r-l• Pi : "P-4 ... :e • Qj • s:: ...I-l • the'discharge at s eve ral points south of Trentonhas been estimated • 0 ''0 ,»S::Qj .,c • t1l • r-l t1l .... by the U. S. GeologicalSurvey. These estimates, which were start ~ .r-l .. 'tl r-l fn • · • .r-! • 0 »(J) ed in August 1953, are based on the record of flow of the Delaware · (:: .,c • 0 o,c • ..:1III .p.. '~:::U River at Trenton plus the estimated contribution from the drainage • area below T:lienton. This contribution is estimated from the records . at gaging atattone on tributaries entering the Delaware below Tren ~· ~ ton. Such gaged tributaries comprise 85 percent of the total tribu ..·'. . ·. . . tary area between Marcus Hook and Trenton on the Pennsylvania side, .. . · . ••· •• · . . ' ,';.'...... I. . and only 28 'perce~of the between Marcus Hook and Trenton area .. . '.•• . I-l · . . . •• Qj on the New Jersey ,ide. Contribution from the ungaged area is de ·..... •• > ~f · termined by use an approximate drainage-area ratio. In table • I-l • • .r-! I-l U I-l • • I-l I-l P::: 22 are the drainase ar-eas in square miles, average discharge rates U I-l U' • U U r-l in cubic feet per 'Iecond, and the years for which the average flow ~Utl(::1-l.~ »(:: fn A Qj U (:: ~~~:;:: was computed fOJ: the main tributaries of the Delaware River be Qj·r-!ttl8~ ttl> .r-! t1l..!l: fn p.,u·;:t:JttI tween Trenton and Marcus Hook. Table 23 lists the values of the I-lI::OE-lIllBr-l (::a Por-l estimated flow atMar-eus Hook and the stream discharge at Trenton ~ ~~eo~(::~ a~~] ~ Qj Qj u from October 1953 through September 1955. ~~~~~~~u:z;p..CI.l 148 :z; p.. At Philadelphia the average mean range of tide is about 6.0 feet. Below Philadelphia the depth and width of the river increases and the tidal range is reduced. The durations of flood and ebb tides vary with location and fresh water flow. The flood tide in the bay is approximately of six hours duration but decreases as the tide pro DISCHARGE, IN MILLION GALLONS PER DAY N. ebb of 21 ceeds toward Trenton, J. The tide is longer duration in ~~0> ~~.8.g"0 ~ ~~~ b ~8 o the Trenton to Philadelphia reach of the river (seven hours) than in o ~0808 o 8 8I , 8 8 8 8 I ! I ! I I I I , I! I the reach of the river from Philadelphia to the bay where the dura tion of its ebb tide is approximately six hours. This is to be ex DISCHARGE, IN THOUSAND CUBIC FEET PER SECOND pected as the net flow must be downstream. 'V - 0000.....aCD IDO "'~ ~ The of the Delaware the quality of the tributaries River affect "'~ water in the main stream in proportion to the volume of water added S from the tributaries and the amounts of dis solved or suspended mat ~ 8 ::! p ter in the tributary waters. The principal tributaries of the Dela Z N 1/ ware River below Philadelphia the Schuylkill, the Christina and are "'o g the Salem Rivers, and the Chesapeake and Delaware Canal. c: _ 1/ 3! z V G) N The precipitation in the basin of the Delaware River is one of the factors influencing the amount of water in the river and is fairly 1/1/ .evenly distributed throughout the year. Intensity of rainfall and the 7 size of the drainage area oftributaries affect the runoff characteris / tics. A short storm of great intensity may cause a flood in a small drainage area, whereas the same amount of rainfall spread out over V several hours may be assimilated without flooding the area. Local V flash floods may-cause local changes in the chemical quality of the tributaries to the Delaware River and of the water in the Delaware / River near the confluence of the tributary. L..,v 1/ At the beginning of the summer of 1955 the water from Reedy /V ~.. Point, Del. upstream contained less than 2, 200 ppm of chloride. 1/ 3 Generally, during the summer months the fresh-water discharge 1.1 "W is lower than in winter or spring. After low discharges have per i/ .n""1'T1 1'-... -2:~f sisted for a while, the salty water moves upriver in that reach of II I'-.. ::i~. a~ the river from Reedy Point to the Delaware Memorial Bridge. For ,,~~~ 17 19 -..... example, on July at high-water slack the chloride concentrations a~~ at Reedy Point and at the Delaware Memorial Bridge were 4,950 -..- " ..n e / • e .. ppm and 2,420 ppm, respectively. On August 2, the concentrations _.... hadincreasedto 5,380 ppmand 2, 880 ppm, respectively. On August -"- ~2""~ 12, 13, 14, 18, and 19, heavy rainfallin the upper part of the Delaware / ~·8 drainage basin resulted in floods above Trenton. The heavy discharge of fresh water flushed the saltwablrseaward and by August 30','the / chloride concentrations at the Delaware Memorial Bridge and at II Reedy 'Point had decreased to 32 ppm and 2,050 ppm, respectively. The fluctuations in salinity of the water owing to change in river co flow are more pronounced at the Delaware Memorial Bridge than ; farther downstream at Reedy Point. Downstream from Marcus Hook to the Delaware Memorial Bridge 151 150 and Reedy Point, the aspects of salinity invasion of the river are be ing given special study. A recorder of specific conductance has been installed at the Delaware Memorial Bridge for the purpose of obtain ~o'.' ing a continuous record of the conductivity which is useful in esti. o mating concentrations of salt present. The specific conductance ~ :=:· increases with rising salinity in such a way that the dissolved solids :z· in parts per million maybe approximated by multiplying the specific conductance in micromhos by the factor O. 6. On August 2, 1955, samples of the Delaware River in or.oss. section were taken at Marcus Hook. The average specific conduct ance of 5 samples taken from the Pennsylvania side, west center, center, east center, and New Jersey side was 3.590 micromhos...... ·, On September 6, 1955, similar sampling was repeated and the .w :z erage specific conductance for the 5 samples was 221 mfcromhos • -l-I · co ~ During the study of 1955 the specific conductance 0'\ :J • summer at co Reedy Point ranged from a minimum of 3, OOOmicromhos at low \0 , The quality of water was repo.rted for 152 wells in the Wissa Ground waters of the nonmarine Cretaceous sediments in north hickon formation and 78 wells in the weathered Wissahickon during ern Delaware range widely in chemical composition. They are rel the well inventory. Of the wells in'the Wissahickon formation, 63 atively low in dissolved solids, soft but high in iron according to 55 percent of the owners, tenants, or drillers reported water of good analyses of samples from scattered wells (see tables 25 and 26). quality, 21 percent reported water hardor slightly hard, and l7per The sampling is representative only in the broadest sense. cent reported iron in the water. In the weathered Wissahickon, 82 percent of the wells were reported to have good water, 17 percent, Lower Aquifer hard or slightly hard water, and 10 percent contained iron. Gabbro Except for one well near the junction of the Christina and Dela ware Rivers (Cd33-2) which shows evidence of salt-water intrusion in the lower aquifer, g round waters are of good quality with the ex Four partial analyses of water from wells drilled in the gabbro, ception that some contain objectionable quantities of iron. (see Cc22-l, -3, -5, and 7, table 25) along the valley of Red Clay Creek, were made in 1955 to define a problem of high chlorides In 14 samples, silica ranged from about 5 to 14 ppm, and aver and zinc contamination. Six of seven wells had been abandoned be aged 7.2 ppm. In 24 samples, total iron ranged from 0.12 to 7.7 cause of the high concentration of chlorides. One well, Cb22-l, ppm, and averaged 2.1 ppm, so there is frequently a treatment ?rob had water with more, than 20 ppm of zinc, an unnatural condition. Iern, Dissolved iron, determined in 7 samples, is low, and aver The wells apparently have been contaminated by waste poxoducts dump aged only o. 16 ppm; however, because of the rapidity with which ed in the vicinity or by infiltration of water of poor qual.ity thr-ough iron oxidizes and settles out, great care must be taken in sampling the alluvium of Red Clay Creek. One well, Cc22-5, appears not to be if dissolved iron is to be determined, and it is probable that it fre contaminated, or, at least only slightly so, and is used more or less quently runs much higher than these 7 analyses indicate. continuously at a rate of about 12 gpm. In 10 samples, calcium ranged from 2.8 to 13 ppm andaveraged Water from one well, Ccll-2, in the weathered gabbro, 67 feet 7.0 ppm. In the same samples, magnesium ranged from 0.7 to 3.2 158 ppm and averaged 2. 1 ppm. I..n 25 .amples, total hardness ranged 159 Table 25.--chemical analyses by U.S. Geological Survey of ground water in northsrn Delaware. (Analyses in parts per million, except pH, color and conductance) Geologic source: Cryst., crystalline rock; Wi.. W188ahlckon formation; G. gabbro; NIIIlt.-, DODIIIIIrlne Cretaceoul sediments; -La, lover aquifer, ... -Ma,mlddle aquifer; -ua, upper aquifer; Ht. L, Mount Laurel sand; Pl, Pleistocene aertes• t lIel1 Geologic Iron Q Hardness Specific ll\Jlllber Depth· source Date ReMrka (ft.) (Fe) s conduct- g g 'i ~ ance J o~ B_ ~ ~ ~_!-3" ---.- (micro- - 3'7.a rot g -: .0 '" • ..;t 101_... • C"') o...t ~ I.E: !-u •. -=-~:I!' .. +. ~ Ca55-1 71.7 PI 7 4-26-51 13 .61 6.8 4.3 7.6 1.1 11 8.2 15 .1 16 95 35 26 136 6.8 3 Analysis of compo Ca55-3 64.6 Pl 7 site s~le, 4 wells. Ca55-5 63.5. PI 7 Temp. 57 F. Cb51-2 62 pl 1 Ca55-1 71.7 Pl 4-26-51 9 5.8 12 19 30 23 5.9 Ca55-3 64.6 Pl 4-26-51 14 7.8 12 13 . 31 20 6.5 Ca55-5 63.5 Pl 12-18-51 11 .00 .00 6 5.1 9.7 1.8 10 9.0 16 .1 24 88 36 142 5.6 7 Al .0, ce .0, Zn .0, Ca55-5 63.5 PI 4-26-51 13 10 16 20 34 23 144 6.0 5 Mn .00. Temp. 560 r. Ca55-7 79 Pl 9-22-53 .03 5~ 10 1.0 9.0 7.8 16 8 5.6 Cb51-2 62 PI 4-26-51 10 5.9 12 20 32 24 5.8 Cc22-1 66.6 G 9-21-55 462 1,690 6.5 Zn)20 ppm. Cc22'"4 90.8 G 9-21-55 13 939 . cc22-5 60 G 9-21-55 9.0 430 Zn 0.4 ppm Cc22-7 84.2 G 550 1,870 6.1 Cc23- IlmK-La 110-2-50 14 .15 8.1 1.8 5.9 24 1.2 8.2.0 10 69 28 6.6 Analysis of compo 1~0 8 site sample, 21 Cc23-9 NmK-La 7 wells. Cc23-10 110.6 HmK-La 7 Cc23-11 HmK-La ? Cc24-1 225 NmlC-La Cc24-2 200 IlmlC-La Cc24-3 150 I!r.llC-La Cc24-4 nuC-La 7 Cc24-5 159.7 HoK-La ? Cc24-6 l!r.1I:-La ? Cc24-7 163.3 llmlC-La ·7 . Cc24-8 140.2 llmlC-La 7 Cc33-1 HmIC-La ? Cc34-1 IlmK-La 1 Table 25.--(Continued) Well Geologic Spec;ific Depth· Number source Date Iron Q Hardneu conduct (ft.) (Fe) .. ~ :I ance (lIic;ro IlemarI<8 g ~ g ~-3 ~~ :I -eII -e" II " mho. at .~ 't: u_ .-tort 0 ~!" -= g -.: .0.. 0'" 1: _ • C"') 0 1""4 1""1 25 C). .. \1'N \Wo 01""4 0_ :~ I.e ~ ~s ~(j ~~ +5 U 1""1 tQ 1""1 U ::J ~ ti :I0 i :;: ~ g :l ...teo s0 ~ 0 0 ::J-'£:- .-1- ...t_.... 0 oP4._- .. .. U ... Cl .. z = co_ f-I Cl U I ...... z '" U Cc34-8 71 NmK-La 7 9-20-55 8.8 .12 8.7 3.2 11 15 9.9 13 .1 21 89 35 23 134 7.0 2 Analysis of compo Cc45-1 221 NmK-La 7 1-11-51 7.0 .75 13 3.1 14 80 4.2 3.4.0 .2 86 45 7.0 site sample, 3 wells Cc45-2 159 NDi{-La Cc55-1 197 NmK-La Cc55-1 197 NDi{-La 9-20-55 2.3 Zn .14 Cd15-1 98 NmK-La 7 6-28-55 49 189 141 3.5 .6 245 90 659 7.6 2 Cd33-2 -- NDi{-La 7 6-28-55 136 10 139 ZIS .2 165 157 1,060 5.4 3 Cd41-2 80.5·Pl and 9-20-55 13 .02 7.9 4.7 5.9 12 20 9.5 .1 9.3 77 39 29 121 7.0 5 NmK-11a Cd43-1 51.5 Fl 7 6-28-55 14 19 25 14 .5 32 16 127 6.0 2 . Cd43~11 88 Pl 7 6-28-55 20 13 5.7 38 5.3 32 21 173 6.3 2 23.7 Pl 4-23-31 14 .03 11 8.1 18 1.2 20 40 27 15 146 61 41 Analysis of compo Cd52-1 site sample, 3 wells Ccl52~2 24.5 PI Cd52-3 24.1 Pl Cd52-1 23.7 PI 4-26-51 13 23 12 7.8 38 27 6.2 Cd52-2 24.5 Pl 4-26-51 12 16 9.8 8.8 29 19 6.3 1,010 6.9 3 Cd52-5 25.8 PI 6-28-55 157 128 82 210 .0 145 40 0 Cd52-13 130 NDi{-Ua 10-28-55 9.4 2.1 .04 3.9 1.5 3.0 1.2 19 .6 2.4.0 1.8 33 16 1 46.7 6.0 6 Temp. 55 F.; Al .0; Mn disil••13; Mn total .18; Li.O; CU .01; Zn .00; P04 .0; Ca-1Ig 16. Dbl1-3 247 Cryst. 9-22-53 .06 13 26 32 12 20 60 39 6.4 Db22-18 12.5 Pl 9-24-53 .07 32 20 30 24 28 35 19 6.0 Dc25-2 199 NDi{-Ua? 6-29-55 11 23 4.2 5.0 8.1 13 0 56.8 6.0 2 Dc43-1 151 NmK-Ua 7 7-6-55 26 83 5.0 3.5 .0 22 0 144 6.9 3 Dc44-1 108 NDi{-ua 7-6-55 5 21 4.0 2.5 .0 14 0 53.3 6.4 2 Ec15-3 178 NDi{-Ua 6-29-55 52 125 26 19 .3 44 0 272 7.4 2 176 NDi{-Ua 9-22-53 .25 41 121 8.8 15 .6 40 0 6.2 Bc15-4 256 7.2 2 Bc15~9 22 PI 7 6-29-55 24 35 53 22 4.7 66 0 2-7-53 .08'.04 1.4 .6 195 308 84 34 52 6 0 916 6.8 3 Bdl-1 35 Kt. L ? P04 0.1; Al 0.3; 30 Kt. L 7 2-16-53 10 .17 .04 32 14 3.9 37 26 25 68 137 107 392 6.2 2 Bc22-1 Mn diu. 0.02 ... P04 0.1; Al 0.0; 0' . Bc33-1 95 Kt. L 7 2-16-53 17 .46 .02 13 3,9 10 11 4.6 28 22 48 40 175 5.9 2 ... Mn diu. 0.01 from 10 to 245 ppm (the maximum probably is affected by salt-water Upper Aquifer intrusion), and averaged 44 ppm. In 14 analyses of water from wells in the upper aquifer, there is The content of sodium andpotassium in the water from the lower no evidence of salt-water intrusion. In 9 samples, the concentration aquifer is low unless the water is contaminated with tidal water. of iron averaged 2.7 ppm; in 14 samples, the hardness averaged 35 ppm; in 14 samples the pH averaged 6.6; in 3 samples, the dissolved In 15 samples, the content of manganese ranged from 0.0 to 0.2 solids averaged 76 ppm. The specific conductance of 5 samples aver ppm and averaged O. 05 ppm. aged 115 micromhos. Thus, generally speaking, the water from the upper aquifer can be described as soft, relatively low in dissolved The anions showed the following concentrations: bicarbonate, 23 solids and high in iron. samples, range 9 to 189 ppm, average 76 ppm; sulfate, 16 samples, range 0 to 141 ppm, average 31 ppm; chloride, 26 samples, range The quality of ground water in the upper aquifer as reported by 3.4 to 218 ppm (the latter indicating some contamination), average the owners is similar to that of the other nonmarine Cretaceous 21 ppm; nitrate, 7 samples, range 0.2 to 21 ppm, average 5.7 ppm. aquifers, except that a greater proportion of the wells, but still a minority, are reported to yield hard water. Of the waters from 33 The ground waters of the lower aquifer were not entirely free wells so reported, 13 were described as good, 3 as poor, 10 as con from turbidity or color. In 13 samples, turbidity ranged from 0 to taining iron in some degree, 5 as hard in some degree, 1 as soft, 200 ppm, and averaged 31 ppm. In 7 samples, the color ranged from and 1 as acid. 1 to 40 and averaged 7. 3. Magothy Formation In 26 samples, the pH ranged from 5.4 to 7. 6 and averaged 6. So Carbon dioxide, determined in 19 samples, ranged from 5 to 35 ppm, and averaged 17. 4 ppm. From the analytical data it is difficult to generalize about the quality of the water in the Magothy formation because samples from Fluoride was determined in only 3 samples. It was O. 0, 0.0, and only two wells (EcI2-14 and Ecl5-3) are available (see table 26). 0.1 ppm. The samples of water from these wells contained 9.0 and 1. 2 ppm of iron, and 40 and 44 ppm of hardness respectively. Dissolved solids in 7 samples ranged from 69 to 189 ppm and averaged 113 ppm. The quality of water from only 5 wells in the Magothy formation was reported: one good, one soft, and 3 containing iron in some de The quality of water of the lower aquifer, as reported by the gree. owners, supports, in general, the analyses. Of 56 wells for which a description of the water was given, 31 were reported as yielding Marine Cretaceous Sediments good water, 2, poor, I, brackish, IS, high or slightly high in iron, 5 soft, and 2, slightly hard. The marine Cretaceous sediments in northern Delaware are re Middle Aquifer presented by the analysis of only one well, Ec21-1, north of the Chesapeake and Delaware Canal at St. Georges, (see table 25; the Only commercial analyses of water from 14 wells in the middle other 2 wells, Ec22-1 and Ec33-1, are south of the Canal and will aquifer are available. Quality similar to that of the lower aquifer not be discussed here). Ec21-1 is a dug well, 35 ft. deep, pre indicated except that no intrusion apparent. Some is salt-water is sumed to be developed in the Mount Laurel sand. The water is what higher concentrations of iron, averaging 3. 5 ppm in 13 samples; sodium bicarbonate in type and has a relatively high concentration somewhat softer water, averaging 34 ppm in 14 samples; hardness of dissolved solids. A nitrate content of 52 ppm suggests possible somewhat lower pH, averaging 6.6 in 14 samples; and somewhat contamination. lower dissolved solids, averaging 89 ppm in 5 analyses; summarizes the comparison. As reported by the owners of 5 wells that tap the M0UI!-t Laurel sand, the waters of 3 of the wells are good and 2 are hard in some The reported quality of water in 42 wells is: good, 25; poor, 6; degree. high or somewhat high in iron, 9; hard, 2. 162 163 Table 26.--chem1cal analyses by cODIDeTcial laboratories of ground water in northern Delaware. (All analyses are in parts per million except pH anda>lor values.) ... Geologic source: Cryst. t crystalline .rcck; Wi, W188ahic~~n formation; We. G, weathered gabbro; NmK-, nonmarine Cretaceous sediments; -La, lower aquifer, -l-ia, middle aquifer, -UB, upper aquifer; l'l,-llelstocene series; Mg, .Magothy formation; Rb, Red t Bani, sand. Analyst: A-,l.meric:an Water Softener Co.; B-Betz Co. j 8GB-Booth, Garrett and Blair; Cu-Cul).1gan wat~r Service; H-Hungerford-& Terry, Inc.; P-Permutit Co. j St-Standard Testing Laboratories, Inc.; W-Wl1mington Testing and Researc:h Laboratory. Some analyses reporting oxides or carbonates ha~e been recalculated to ions:. Q' Well Geologic Iron Hardness ~ Z Number Depth , source Date .. ~ ~ ~ ,~ ! :I "2 o~ (ft.) ~ ~ ...... -8 > • u ~ u~ u~...... ,~~ .... ~ ~ ~ c '" ... .. •.. :: .a '"' .. ~ ...0 '"...... ::l .... 0 .. 1] u ...... + .. t~ "0...... '"' ,; ...... u ~u "'$I 0'" ..... I.e o .a .0 t~ N .. 0 ... ,,~ "'u ...... 0 u=~ ..... ,r::~ .... ~ '3 ~ .. ~ "'~ ~ ,~ .. o ... 6 ... is'" I! o le 2: CI 0 " .. '" .. o u e 2: =Po U ... ! Bb25-14 19.7 Wi 9-21-55 70 48 7.0 a4 6.9 B Bb25-15 Wi 9-21-55 60 56 6.5 102 6.5 B Bb25-16 Wi 9~21-55 52 60 5.5 90 6.3 B Be24-1-6 11U-243 Wi 7-9-54 Trace 40 16 7.5 68 6.1 B Cel1-2 67 lie. G 1-5-53 14 1.2 0.2 4.7 1.9 9.3 32 6.0 W Ce34-15 112 NmK-La -- 1.3 10 31 23 17 5.6 5 8GB Ce45-1- 159-221 NmK-La 1-21-54 8.0 3.5 11 3.1 7.4 66 0.0 5.0 22 41 .0 6.8 1 70 H 2, 55-1 Cd15-1 98 NmK-La 77~ -53 .6 n(a) 139 11 120 16 231 7.2 'W Cd15-2 298 Cryst. 7- -53 15 20(b) 52 6.7 84 158 7.4 W Cd33-2 IlmK-La 77-22-52 > .5 23 42 6.4 St CM1-1 80 IImK-Ma 9-15-54 34 32 9.0 42 5.9 B CcI41-2 80 Fl. and 9-15-54 42 24 8.0 40 5.7 B NmK-Ma CcI43-3 118 PI 1 1-4-50 .0 2.9 1.7 7.1 6.4 A Cd43-4 110 f1 7 6~29-49 .0 6. .8 14 5.8 A cM3"" 110 PI 7 1-4-50 .0 2.9 2.6 7.1 6.8 A cM3-5 94 PI 7 1-4-50 .0 17 8.4 28 5.8 A CcI43-6 71 1'1 ? 5-6-52 4.0 5.7 3.5 4.1 8.9 5.0 6.2 A CcI43-11 aa PI? 8-10-51 5.1 2.4 11 5.8 A 'CcI43-11 88 i'l ? 5-6-52 4.0 5.7 3.5 4.1 8.9 10 , 6.2 A CcI43-12 52 llmK-Ua 77-22:52 .5 15 55 6.6 St CM3-13 79 NmK-Ua, 77-22-52 <.5 23 42 . 6.4 St Cd52-13 130 _-Ua .5 16 4 0.0 27 14 6.1 0 , De25-1 426 _-La 78-11-48 4.5 8.8 1.4 50 2.0 5.0 4.0 5.0 28 7.3 40 15 P ~ le203 + A1203 - mostly Pe203 \O} Pe203 + A1203 mostly AI203 40 7.2 52G P De25-2 199 _-Me 8-11-48 2.5 12 2.2 69 3.G 4.0 .0 10 4.0 5.0 10 6.6 3 , P DeC-3 400 - 500 _-La 8-11-48 .2 2.8 ' .7 9 .0 6.0 12 1.0 69 2.0 5.0 ..0 3.0 34 7.6'0 5 P De25-4 , 300 Nait-Me 8-11-48 1.2 P 8-11-48 .2 3.6 1.2 9 6.0 7.0 4.0. 5.0 14 6.6 3 5 De25-5 100 Nait-Ma 6.2 P Nait-Me 2-16-37 .1 2.0 1.9 8.0 20 13 Dc25-6 185 4.0 11 6.5 5 5 P 185 Nait-Ma 8-11-48 .1 2.8 1.0 8 7 .0 4.0 10 De25-6 '4.5 40 38 6.5 8GB Dc41-4 539 _-Ma 10-12-55 4.4 0.1 70 and La .0 85 1.1 8.8 12 7.3 10 8GB Dc42-6 698 Nait-La 2-3-56 .33 8GB Nait-La 10-6-55 3.2 .1 82 19' 35 52 6.6 De51-7 544 6.7 8GB Nait-La 10-7-55 2.8 .1 80 19 31 52 De51-7 544 44 6.8 8GB 255 Nait-Ua 2-16-56 4.0 .1 62 3.4 22 De5l-8 44 42 6.4 8GB Ge5l-8 255 Nait-Ua 3-7-56 4.8 .1 62 2.0 .0 .0 14 6.5 31 2,4 10 6.0 0 BGB De52-1 ro - 90 PI 6-4-54 11GB 6-15-54 9.0 De52-1· 79 - 90 PI 6.7 8GB 7-6-54 6.0 6.0 0.8 .1 68 5.5 30 88 34 De52-1 328 - 340 _-Me 40 6.7 25 8GB De52-1 320 • 340 _-Ma 8-2-54 7.0 4'.5 .1 82 4.0 35 .1 100 16 15 28 7.1 0 8GB De52-1 520 - 540lldl:-La 7-21-54, 5.6 .24 8GB _-La 7-12-54 6.0 5.3 .2 .1 80 6.5 29 118 44 6.6 De52-2 481 10 6.6 0 8GB 85 PI 10-8-54 10 .6 .0 18 2.1 5.5 8.8 De52-5 26 48 10 6.1 250 8GB De52-5 85 PI 11-5~54 10 14 .1 .5 2.3 .8 15 1.7 7.0 .1 .0 13 2.5 65 4.9 4.0 31 78 42 6.6 35 8GB De52-24 3'3 Nait-}Ia 12-9-54 6.0 3.0 8GB 6.0 3.3 .0 .0 14 1.6 68 4.3 4.0 29 82 40 6.7 35 De52-24 333 Nait-}Ia 12-12-54 8GB 6.0 2.8 .1 .0 13 2.1 70 4.9 4.0 33 88 40 6.6 De52-24 333 Nait-}Ia 12-15-54 6.6 8GB Nait-Ua 6.0 5.3 .2 .1 80 6.5 31 44 De52-34 465 - 485 -- 21 20 2.5 6.1 12 8GB De53-5 90 PI 12 .7 .0 18 9.5 -- 85 12 8.8 22 7.3 8GB De53-7 655 - 660 Nait-La 10-1-55, .2 8GB 1.4 ,.0 84 4.0 13 110 56 7.1 55 Dc53-23 170 - 210 _-Ua 8-3-54 7.0 .3 6.5 10 8GB _-}Ia 8-25-55 7.0 5.5 .1 70 4.0 44 38 De53-23 383 - 423 29 20 2.56.1 12 8GB De53-31 70 - 90 PI 7-12-55 12 .7 .0 18 9.5 34 6.5 8GB Nait~Ma 12-6-55 7.5 .1 60 2.5 40 !b15.2 245 34 6.5 150 8GB 245 Nait-}Ia 1-5-56 8.2 .1 63 5.0 44 Bb15-2 31 44 6.7 8GB IbIS-4 541 _-La 10-21-55 2.0 .0 82 10 .1' 90 5.3 11 18 126 22 7.0 30 8GB Be12-3 548 - 553 _-La 11-1-54 7.0 2.8 .1 8GB .6 .0 2.4 1.5 15 3.6 8.5 22 64 12 6.1 Ec12-10 29 - 39 PI 3-15-55 10 1.9 6.0 ,. 8GB 3-16-55 10 .3 .2 .0 3.0 2.1 16 3.6 9.5 26 . 59 16 BCU-10 29 - 39 PI 6.5 8GB 8-9-54 9.0 9.0 .3 .2 55 3.0 35 76 40 Be12-14 118 - 158 Mg 44 6.6 50 8GB Be12-15 303 - 3lkl _-Ua 8-19-54 6.0 5.2 .6 .1 68 5.5 '1 88 12 22 116.- 32 6.9 200 8GB BC12-15 585 - 590 _-La 9-2-54 7.0 4.2 .5 .0 90 10 9.0 13 20 1.1 .0 8GB Bel3-6 524 - ~66 llmK-La 1-24-55 6.0 1.3 .0 .0 4.3 2,.3 .0 . 3.7 2.1 92 9.5 8.0 13 18 7.1 0 BCII Eel3-b 58i .,: 592 _-La 1-26-55 6.0 1.2 .0 8GB 1.2 1t.3 1.8 90 7.3 8.5 13 18 7.1 0 Be13-6 524 - 566 _-La 1-31-55 6.0 .0 .0 20 7.3 0 8GB _-La,? 2-10-55 6.0,1.1 , .0 5.7 1.4 92 4.9 9.0 10 Bel3-6 40 7.0 186 28 7.4 70 8GB tc1~-l' -- 9-24-54 7.0 2.5 .3 .0 85 21 678 -' 683 _-La 85 21 '43 13 24 7.1 8GB BC14-1' 678 - 683 NmK-La 10-8-54 1.0 2.0 .0 Cu ~ 2.0 116 16 44 7.0 Ee15-3. 148 - 178 Mg -- 1.2 15 CP- '4, 5 U! 12 22 82 87 5.5 Cu Be15-6, 18 - 23 PI and Rb -- .1 14 7, 8, 9 Two wells in the Wenonah sand yield good water, 1 yields hard Table 27.--Selected analyses of water from wells at water, and Z yield water high in iron. Hercules Experiment Station in the Red Clay Creek valley. Of 16 wells in the Red Bank sand 9 are reported to have good water, Z have water that contains iron is some degree, 3 yield Analyses by chemists of the Company. hard water, and Z yield soft water. The analyses which record highest and lowest Pleistocene Series chloride are given. In general, when chloride was high other constituents were high, but there are some exceptions, for example, see Bc52-l6. Nonpublished The ground waters of the Pleistocene series in northern Dela analyses are in the open file at N~~ark. ware, as indicated by Z9 analyses, range widely in composition, but on the average have a moderate concentration of dissolved sol Wells are in the Be quadrangle, so each number ids, are soft, and have slight amounts of iron. The wide range is bears a Be-prefix. no doubt indicative of the several Pleistocene depositional environ ments, the different rocks with which the Pleistocene is in con (All analyses are in parts per million except pH) tact, and the differing conditions of intake. tb Q,ltO In 16 samples, total iron content ranged from 0.00 to 14 ppm, l/) to ~ :»0\ to and averaged 1. Z ppm. It should be noted, however, that the sample ..-t ..-t Q,l I:: CllI.t: 0 to reported to have 14 ppm of iron had a turbidity of Z50 ppm. Red I:: to bO 1-1 Cll to COM'r!~ .r! to "'0 water, therefore, is fairly common. The concentrationofmanganese O\.t:tOQ,l Cll .r! u Il-I..-t Q,l"'O "'0 a ..-t ranged from 0.0 to O. 1 ppm. o Il-I:;: .r! Q,l to or! Q,l 00 I:: a a 1-1 :>- to I:: '"Cl Q,l tOO 1-1 Q,l ..-t 0 ..-t Q,l Q,l M 'r! M'r!_ ~- 0 In 14 samples, calcium and magnesium were low (average 5.9 The pH of water from the Pleistocene series in Z8 wells ranged 52-7 1 1-20-37 0.03 40 28 2.5 6.5 from 5. 6 to 6.9 and averaged 6. Z. Free carbon dioxide aver-aged Z3.4 ppm in water from 7 wells. 52-8 29 3-21-45 0.09 65 54 14 30 140 7.0 1-20-38 0.02 50 43 4 7.0 The Pleistocene series appears better sorted andless silty than the nonmarine Cretaceous sediments, if the turbidity of well water 52-9 28 4-22-53 <0.01 21 14 11 19 6.8 is taken as a guide. Five wells in the Pleistocene series showed a 1-20-38 0.07 34 29 2.5 6.8 range in turbidity from 0 to lZ ppm, and the average was 5.8 ppm. In samples from 24 wells in the nonmarine Cretaceous aquifers the 52-10 22 12-18':"46 0.05 36 41 13 6 6.3 turbidity of the water ranged from 0 to ZOO ppm and averaged 40 2-11-38 0.11 29 34 2 6.8 ppm. 167 166 Table 27.--(Continued) Table 20.--Periodic analyses of chloride content in wells at Atlas toint, Del. I:l Well Humber Cd43-5 Cd43-11 Cd43-3 Cd43-4 Depth a lD ..-I "tJ ..-It,) (in ft. below 93 1/2 38 117 1/2 110 "tJ r-l 1sd) III 00 r-llll> III lDO Altitude r-l o~ 4J_ 0 III ..;t>-l r-l (in ft. above 11 13 34 31 r-l lD_ I.W 0 III lD ~ r-lC/:l4.!4J ms1) "f"I :J - 0 III Q C/:l E-c Near tidal Farthest Location drainage Midlolay from 52-13 22 4-22-53 <0.01 64 38 61 24 6.6 1-24-39 0.10 ditch ditch 70 51 4 30 6.3 C1 (ppm) C1 (ppm) C1 (ppm) C1 (ppm) 52-14 26 6-14-49 0.21 59 63 61 36 6.7 6-29-l~9 14 3-9-39 0.03 27 32 4 44 6.3 1-l~-50 28 7 7 7-10-39 2 5-6-52 10 8-lS-54 25 32 30 5 52-15 23 8-8-45 0.01 17 62 65 26 158 6.4 9-15-5l~ 15 25 25 5 10-3-41 0.50 37 31 6.3 o 93 6.3 10-15-5f} 10 15 15 5 11-17-54 25 30 30 5 52-16 23 6-27-49 0.12 43 41 40 192 6.0 12-17-54 15 25 25 o 10-31-44 3.6 387 8 16 2000 0 854 5.1 1-20-55 20 1-21-55 15 20 o 52-17 21 7-9-47 0.03 48 50 50 3 6.4 2-21-55 7 11 10 o 2-6-52 0.06 58 43 16 12 3-18-55 15 15 30 5 6.3 n 4-29-55 25 30 30 o 52-18 16 2-16-55 0.06 79 ~6 21 22 6.6 5-18-55 20 20 25 5 10-14-46 0.12 59 50 3 10 116 6.3 6-17-55 20 35 10 357 6-23-55 33 52-19 3 4-22-53 0.01 68 43 16 19 6.7 7-31-55 10 20 16 5 2-16-55 0.02 81 48 12 17 6.5 8-17-55 16 12 20 2 10-21-55 2 24 25 20 52-20 3 4-22-53 0.04 47 25 13 19 6.8 1-6-56 55 10 40 5 4-6-54 0.02 55 25 8 19 6.5 2-15-56 50 1~0 35 o 3-16-56 70 60 40 o In summary, then, the Pleistocene series, which yields the lar gest quantity of water to wells in northern Delaware, at the greatest rates, has, on the average, the water of best quality, although it contains some iron. The main discharge of ground water to streams on the Coastal Plain is from the Pleistocene series, and the good quality of water in these streams reflects the good quality of the water in the Pleistocene deposits. Intrusion and Contanlination The intrusion of saltwater into the fresh ground-water supplies 169 has occurred only at a few small areas in northern Delaware. How 168 ever, it poses a threat along the Delaware River, and along the .. Chesapeake and Delaware Canal, so that care may have to be taken Ql r-l in adjusting pumping rates, and a watch should be established, by ol-I (,J· ('f') II'l \0 10 Ql ('f') 0 means of outpost observation wells. In at least 3 places in north- ~ N N r-l oIII " ern Delaware the pollution of streams or stream banks, by indus- trial wastes has contaminated the ground water supplies with soluble ~ Z r-l chemicals. >0· 0\ ol-I Z N III ,,-.. Table l7 presents selected analyses of water from wells at the s:: 0 0 The concen- r-l .... Hercules Experiment Station in the Red Clay Valley. I r-l ol-I· 0 0 trations of chloride, sulfate, and total solids in the water from some r-l (,J 0\ -:t "0 .... 0 r-l N of these wells have been unnaturally h~gh,and are evidence of con- s:: a III tamination, probably by influent seepage from Red Clay Creek, which ~ ('f') Ql has been the subject of a study by the Water Pollution Commission I Po ol-I · r-l (Kaplovsky, 1950-55). The wells of the Haveg Corporation in gabbro 10 N ol-I N along Red Clay Creek have been contaminated with zinc chloride (see I ~ " III table l5, analyses Cell-I, -4, -5, and -6). This contamination may Po r-l be influent seepage from waste piles or fill along the creek banks. I s:: 00 N .... 0 II'l N Table of chloride in "0 l8 summarizes periodic analyses water from tJ ii wells at the Atlas Point plant of the .Atlas Powder Company. The analyses indicate some infiltration from a tidal drainage ditch. § r-l -:t :::l Ql ..., "r-l Increasing concentrations of chloride, are threatening the shal- ii low water supply in the gallery and wells of the city of New Castle, Ql as indicated in table 19 and cited by Henderson in 1951. To control ff s:: \0 •..1 :::l 00 this situation, the tidal gate has been rebuilt at the outlet of Broad ~ ..., r-l :::l and there seems to be some decrease in the chloride 'tl Dyke Creek, concentration in 1956. This decrease also may be the direct result s:: I r-l r-l 0 I• 00 r-l of use of the deeper well, and rest for the gallery system during the ~ .... r-l N With of r-l ol-I period June to ~ovember,1955, restoration water levels, r-l III ~ some of the intruded salt water was flushed out. The encroaclunent ] ol-I 10 s:: 00 N may be from the Delaware River, half a mile east of the well field. Ql N 00 r-l 00 U " "r-l N r-l ~ s:: The city of New Castle also has experienced manganese contarrdw ~ 0 4-1 (,J nation at their well on 4th Street (Ddll-l). It appears that this is ~ "0 ~ r-l \0 0 Dyke · r-l due to fill of part of the Broad marsh with manganese waste Ql Ql III 0\ 00 ol-I ol-I ~ r-l N r-l products. The new deep well of the city, Cd5l-13, shows relatively III ~ ~ 0 high total manganese of O. 18 ppm (table l5). A well - field testin Po s:: Ql June 1955 indicated a hydraulic connection between the Cretaceous 'r! ~ -:t 0\ t"'\ .g· 0\ -:t \0 aquifer of this well, and the Pleistocene deposits beneath Broad Ql r-l N r-l 'tl a f<.o Dyke marsh • •r! ~ ~ .... 0 r-l eo co co 0\ II'l -:t r-l 0 0 It maybe concluded that contamination of ground waters in north- ..c ~ ~· 0\ 0\ 0\ r-l co co 0 -:t \0 Delaware has so been limited to a few of small extent, "oJ ..., r-l r-l r-l N N r-l ern far sites tt but ·that continued care must be exerted to prevent it on a larger I 0\. scale. N Ql r-l r-l 00 0\ 0 r-l N ('f') -e II'l \0 M -:t -:t II'l II'l II'l II'l II'l II'l II'l .g 0\ 0\ 0\ 0\ 0\ 0\ 0\ 0\ 0\ 0\ 171 f-! r-l r-l r-l r-l r-l r-l r-l r-l r-l r-l 170 pose use with industry using almost 63 percent of the total, a large part of which is used for cooling and washing processes. The re ~~~~OO~~~O~O~~~NO~~O ~ maining 37 percent ( Z3 million gallons) is divided among all other 3o i~~~=~~~~~~~~~~~g~~~~ ~ purpbses of use with domestic use accounting for the major portion. .. ~ ~~~~~N~~~~~N ~ 0 ~ ... .., ::l Most of the fresh surface water used by industry for cooling and wash .... ing processes is returned to the stream from which it was taken, thus sustaining the flow of that stream. 0\0 ~ ~'" N C:O~ 0~ ~ Table 31 lists the distributors or users of ground water in rela tion to the geologic source from which it is derived. Water removed o 0 ... g g~ from the ground generally requires less treatment before use, than ... ..,... water from streams andis less subjectto sudden extremes offlood '":~-:t;~ ing and drought. They are confined in natural storage reservoirs U"I,...,.-t\D C:OCON\D beneath the earth so that they do not preclude the use ,of the land ...... , under which they lie. Unfortunately, much of the Piedmont area is ""; underlain by crystalline rock which does not yield water in great '"... quantity to wells. Although yielding sufficient water fei;' domestic and farm uses, wells with high yields suitable for industrial or mu nicipal purposes are relatively few. Therefore surface sources of o:c; ... supply must be used when large quantities of water are needed. In ...... Municipal water systems are those systems owned and operated 175 174 byan incorporated town or city to supply the water needs within the works Corp.). The maximum purchased was 10.2 million gallons corporate limits. Water is generally supplied for part of the in in September, and the minimum was 7.2 million gallons in March. dustrial use, and almost all of the commercial and domestic use. , Some industries within city limits process some or all of their water Evidence of the rapid growth of the Newark area is the steady from private sources. In northern New Castle County, the cities of rise in the amount of water used per year, from 241 million gallons Wilmington, Newark, and New Castle, and the town of Newport have in 1950 to 324 million gallons in 1955. This indicates an &verage municipal water systems. annual increase of 16.6 million gallons. In order to meet these ex panding needs, the city has purchased the former Phillips Packing Wilmington Company property on which a well, Ca55-4, capable of producing more than 300 gpm is located. In adQition, an area south of Brook side has been geologically and geophysically explored, and one pro The municipal water supply for the city of Wilmington is obtained duction well, which yielded 360 gpm in a 2-day test in June, 1956. chiefly from Brandywine Creek. During 1955, a total of 9. 0 billion has been drilled. Other well sites have been located in the same gallons of water was pumped from the Brandywine. an average of area. A detailed study of the Newark area, including the operating nearly 25 rngd, The maximumpumpage occurred in July when more well field in the north basin and the new well-field site in the south than 1 billion gallons were withdrawn, and the minimum in February basin has been described by Groot and Rasmussen (1954). when about O. 6 billion gallons was pumped. Ground-level storage facilities for untreated water of the city of A reserve supply of more than 2 billion gallons of raw water is Newark have a capacity of 180,000 gallons. Treated-water storage stored in the Edgar M. Hoopes reservoir. This reservoir, on a small facilities, in elevated tanks, have a total capacity of 784,000 gallons, tributary to Red Clay Creek, impounds some water from the small which will be increased 300, 000 gallons with the addition of a tower watershed above the dam, but most of the water in the reservoir is to be constructed in the near future. The rated capacity of the treat pumped from Brandywine Creek. During 1955, a total of 115.5 ment plant is 1. 3 million gallons a day. million gallons was withdrawn from this reservoir, with a maximum monthly withdrawal of 19.0 million gallons during January, and a Data on water use by type of user in the Newark area are not minimum of 4.7 million gallons during July. Storage of approxi readily available, but it is reported that industry USes only a small mately 55 million gallons of finished water is located at Cool Spring amount of the total. The University of Delaware, together with num reservoir. Rockford Tower, and Rodney reservoir. erous commercial establishments, probably account for a lrignificant • portion of the water used, but the largest amount is used for domestic The rated capacity of the Wilmington treatment plants is approx- purposes. imately 32 million gallons per day. Commercial and industrial use of water in and near Wilmington. accounts for more than 50 percent New Castle of the water processed. Domestic use is about, 47 percent, and the remainder is used by various municipal departments of the city. The water sources of the city of New Castle are wells producing For 1955, the average alkalinity as CaC03 of the treated water from two aquifers. The system of shallow wells (about 25 feet be distributed by the City was 41 ppm; average hardness. 55 ppm, tur low land surface), which includes Cd52-l, -2, -3. and -10. with bidity, 0, and the average pH was 7.5. interconnecting galleries (Marine and Rasmussen. 1955, fig. 22), yielded 74.0 million gallons of water for the eight months. January Newark to July and December 1955. The maximum pumpagefrom this sys tem was during March and April, when 14.9 million gallons was withdrawn each month. A minimum of 138,000 gallons was pumped Approximately 2/3, or 221 million gallons of the water usedbJ during June when both aquifers were used. From May through De the city of Newark during 1955 was pumped from the city's wells cember 1955, well Cd52-l-3, screened in -a lower sand (116 to 132 Ca55-3, 55-5, and Cb5l-2. The maximum pumpage occurred in feet below land surface), produced 104.3 million gallons. The max July when an estimated 22 million gallons was pumped, and a min imum amount pumped from this aquifer was 15.3 million gallons imum in November when an estimated 16 million gallons was pump during July. and a minimum of 10.9 million gallons during May ~n ed. In addition to this source. Newark received more than 103 million both shallow and deep aquife r s were pumped. The total production gallons of surface water in 1955 from the treatment plant atSmalleys of water from the New Castle well field for 1955 was 178.4 million Dam on the Christina River (Delaware Water Co. of General Water gallons. The highest pumpage of 16.3 million gallons occurred in 176 177 July, and the lowest of 14.4 million gallons occurred in January. General Waterworks Corporation The water demand at New Castle has been relatively constant the last 5 years, and even showed a slight decrease in 1955. Delaware Water Company The storage capacity for raw water is about 150.000 gallons and that for treated - water storage is almost 2.2 million gallons: The Delaware Water Company, recently purchased by the General 45,000 gallons in a clear well; 600,000 gallons in an elevated tank; Waterworks Corporation, processes surface water at two treatment 300,000 gallons in a standpipe; and 1. 25 million gallons in an emer plants, one on the Christina River at Smalleys Darn near Christiana, gency reservoir. The rated capacity of the treatment plant is 1.25 and the other just south of the junction of Red and White Clay Creeks mgd, near Stanton. Commercial and industrial metered water use in New Castle in The plant at Christiana utilizes water from a darn impounding the 1955 was approximately 41 percent, or 73.1 million gallons, of the waters of the Christina River. A total of 1. 3 billion gallons was total. A large proportion of the remainder was used for domestic pumped from this source in 1955, with a maximum of 132. 3 million purposes, and the balance used for general municipal purposes. gallons being pumped in October. and a minimum of 83.3 million gallons in February. Water processed at the Stanton plant from Adiscussion of the geological conditions at the site of the Water White ClayCreek totaled more than 1. 2 billion gallons in 1955. The Works is given on page 113. maximum pumpag e occurred in August when 110.3 million gallons was pumped and the minimum occurred in September when 83. 6 Newport million gallons was pumped. Total pumpage from both plants of the Delaware Water Co. was more than 2 1/2 billion gallons in 1955. The combined pumpage of the two plants reached a maximum of The municipal water supply for Newport is produced from city 238.7 million gallons during July, and a minimum of 181. 0 million owned wells Cc34-2, -8, -10, -11, and -12 in the town limits. For gallons in February. • The rated capacity of the treatment plant at the 12 months from August 1955 to July 1956 a total of 45. 8 million Christiana is 5 mgd, and the Stanton plant is 4 rngd, gallons was pumped from the ground. An additional source of ground water supply fo..~ Newport is the Artesian Water Company, which Approximately 1/3 of the water processed at the Delaware Water supplied 5. 3 million gallons to the town over the same period. Company plants was supplied to the municipal systems of Newark and Newport, and to the Wilmington Suburban Water Corporation, Water produced by the town is untreated,• but that supplied to the the New Castle County Water Company, and the Artesian Water town by the Artesian Water Company is treated with powdered mix Company. Industrial firms, such as the Pennsylvania Railroad, the tures of chloride and lime. Storage facilities for 60. 000 gallons are DuPont Paint Plant at Newport, the Chrysler plant at Newark, and maintained in one elevated tank. Approximately 85 percent of the the Delaware Power and Light Plant at Edgemoor, use a major por water is used for domestic purposes, 12 percent for commercial tion of the remainder. purposes, and 3 percent by industry. Wilmington Suburban Water Corporation LARGE PRIVATELY OWNED WATER SYSTEMS The Wilmington Suburban Water Corporation utilizes w~terfrom Anurnber of large privately-owned water systems have been es 3 surface water sources; Bellevue Reservoir, White Clay CreeK tablished in New Castle county in response to the needs of those in (purchased from the Delaware Water Company), and the Delaware dustrialand domesticusers in areas not supplied by municipalities. River (purchased from the Chester Municipal Water Authority). Althoughmollt of these systems were e stablished primarily to serve Water processed from Bellevue Reservoir totaled more than 123 domestic users, some of them now process large quantities of water million gallons in 1955; a maximum of 15 million gallons was pumped for industrial and commercial use, as well as augmenting some mu during July, and a minimum of 7.0 million gallons in June. A total nicipalsupplies. One notable exception is the Delaware Water Com of 278.4 million gallons was purchased during 1955 from the Delaware pany of the General Waterworks Corporation, which processes water Water Company. A maximum of 27.6 million gallons was purchased mainly for industries and other water companies. Although more in November and a minimum of 17.4 million gallons was purchased numerous. private systems supplying ground water account for only during March. A total of 46.1 million gallons was purchased during about 20 percent of the total ground water processed. 1955 from the Chester Municipal Water Authority. A maximum of 179 178 7.4 million gallons was purchased from this source in July and a Delaware City Water Company minimum of 0.8 million gallons was purchased in November. The total amount of water distributed by the Wilmington Suburban The Delaware City Water Company, processes water from wells Water Corporation during 1955 was about 448 million gallons. The Ec15-l and -2 to supply the Delaware City area. Pumpag e records highest amount distributed was 49. 4 million gallons during July and are not maintained by this company, but estimates based on well the lowest was 32.0 million gallons' in February. The estimated yields, pump capacities, and other means, indicate that more than raw-water storage for this company is 100 million gallons stored 47 million gallons of water was pumped in 1955. Because Delaware in Bellevue Reservoir. The treatment plant at that site has a re City is primarily a residential area, it is probable that most of the ported capacity of more than 1 mgd. water was used for domestic purposes. The construction of the Tidewater Oil Company refinery near Delaware City is expected to Water distributed by this company is used mainly for domestic create an additional demand on the facilities of the Delaware City purposes in the suburbs north of Wilmington. Smaller amounts are Water Company as more people move into the area. supplied to commercial and other units, such as schools in that area. Collins Park Water Company Arden Water Company The Collins Park Water Company derives all of its water from The Arden Water Company processes water from an impounding wells Cd42-l, -4, and -5, drilled in an area within the community, dam on the south branch of Naaman Creek. During 1955, 63.2 mil Approximately 37.9 million gallons was pumped from this source in lion gallons were used from this source to supply domestic users 1955. Operated primarily to serve the needs of residential units, in the Arden area. A maxrmum of 7. 1 million gallons was process _ nearly all of the water processed is used for domestic purposes. A eddurrng July, and a minimum of 3.4 million gallons in each of the small amount is used for commercial purposes. months of November and December. Willow Run, North Star, and Sedgely Farms Water Companies Artesian Water Company These companies, although geographically separated, have much The Artesian Water Company, wh9se main office is in Newport, in common. All 3 companies use a ground-water sour ceo Designed pumps nearly all of its water from wells. Well fields for this com and operated primarily to serve residential areas, almost all of the pany are widely distributed over an area south and southwest of water is pumped for domestic purposes. Wilmington, and include well fields at Tuxedo Park and Newport Heights in Newport, at Wilmington Manor Gardens, Midvale, Llan Pumpage records maintained by the Willow Run Company show gollen Estates, Green Briar, Eastburn Heights, Castle' Hills, and that approximately 21. 2 million gallons of water was pumped from Glendale. In additfon to these ground-water sources, this company wells Ccl4-l, -2, -3, and -4 in 1955. The highest monthly total purchases some surface water from the General Waterworks Corpo was pumped in July when 2.3 million gallons was pumped, and the ration. The total pumpage from all sources was 945. 6 million gal lowest monthly total of 1. 5 million gallons was produced in February. lons for 1955, an increase of 116.1 million gallons overthatpwnped Records for the Sedgely Farms and North Star Water Companies are in 1954. The maxrmurn pumpage for 1955 occurred in July when not available, but an estimate based on purnp capacities, well yields, 101. 5 million gallons was pumped, and a minimum in February when and population served, indicates that the Sedgely Farms pumping 62.8 million gallons was pumped. The well field at Llangollen Es station distributed more than 4. 0 million gallons of water during 1955, tates produced about 43 percent of the ground water pumped by the and the North Star Company distributed more than 5. 0 million gal Company. lons over the aarne period. Water distributed by the Artesian Water Company is used pri New Cast],e' County Water Company marily for domestic purposes. Water is furnished to more than 75 residential communities, a detailed list of which are to be found in Delaware Geological Survey Bulletin 4 (Marine and Rasmussen, This company acts as a distributor for water purchased from 1955, p, ion. An estimate by company engineers indicated that the General Waterworks Corporation to the residential communities only 1. 2 percent of the total distributed was used for commercial purposes. 181 180 of Brookside Park and Chestnut Hill Estates. Investigations of a probably will be the major user of brackish water when the refinery source of ground water in the Brookside area have been conducted at Delaware City is placed in operation, with as much as 396 mgd by this company, and a number of wells have been drilled which expected to be withdrawn from Cedar Creek near its outlet. show promise of being a major source of water for this company. It is estimated that during 1955, an average of about 300,000 gallons Fresh-Water Use a month was supplied to 1800 customers in the Brookside-Chestnut Hill area. This would indicate that approximately 3. 6 million gallons of water was distributed by the New Castle County Water Company Many industries, in northern Delaware are located in valleys, during 1955. This company plans to supply water to the communities near streams where quantities of fresh water are available. Like of Hillside Heights and Birchwood Gardens which are under construc brackish water, much of the fresh water is used for cooling by in tion. dustry. Fresh water, however, is used for many other industrial processes. The washing process is probably the next greatest use INDUSTRIAL WATER SYSTEMS for fresh water and is necessary in the processing of paper, fibre, and other products. Air conditioning of office buildings, although not considered an industrial process, accounts for a part of the total Industrial water systems are defined as those systems owned by fresh water use during approximately 5 months of the year. an industry which produce and utilize water for that industry's use. In most cases they are one-company systems with sources of supply Ground- Water Supplies at the manufacturing site. Water supplies for industrial use may be either surface water or ground water or a combination of the two. Adiscussion ofthose industrial supplies follows, with those of com A nurnb e r of industries have located in areas where ample ground panies using both surface and ground water discussed under ground water supplies are available. Some are in areas where sediments of water supplies. the Coastal Plain yield large quantities of water and others are in stream valleys of the Piedmont area where wells with moderate Surface-Water Supplies yield are fed in part by induced infiltration from surface streams. Industries in this section are listed in order of decreasing ground water use. Those industrial systems using surface water may be divided into two groups, those using brackis1) water and those using fresh Atlas Powder Company water. Brackish- Water Use The Atlas Powder Company is the largest industrial user of ground _ water in northern Delaware. Although more than Z5 test holes have been drilled, for the sake of clarity, a figure in Vol. n The use of brackish water by those industries listed in table 30 gives only the locations of production wells. A total of almost 591 is predominantly for cooling purposes. In many manufacturing pro million gallons of water was pumped from wells Cd43-3, -4, -5, and cesses and especially in the production of electricity by use of steam, -11 during 1955. The highest monthly pumpage, nearly 56 millicn large amounts of heat are generated which must be removed if the gallons, was in August, and the lowest amount, 37. 4 million gallons, process is to continue efficiently. In order to remove this heat, was in June. It is reported that chloride contamination has caused large quantities of water are pas sed through cooling coils or con the abandonment of those wells in the marsh areas near the river. densers where some of the heat is transferred to the water. Mohawk Carpet Mills, Inc. The largest single us e r of brackish water in northern Delaware is the Delaware Power and Light Company at Edgemoor. Water is pumped directly from the Delaware River. chlorinated to control The Delaware Rayon Division of Mohawk Carpet Mills, Inc. is organic growth in lines, circulated through cooling systems, and about two miles southwest of New Castle along the Delaware River. returned to the river. Well sites at this plant are shown in a figure in Vol. n. Numerous test holes and wells were drilled on the property, but wells DcZ5-Z The Tidewater Oil Company, although not listed in table 30, and -3 now produce most of the water used. -An estimate based on 183 l8Z well capacities, pump size, and length of operation, indicates that was 4.71 rrri.Ilion gallons in De cernbe r , Noxrnal.ly, the highest month about 220 million gallons of water was pumped frorn these wells in ly pUIIlpage occurs in July or August when act ivities of the Hercules 1955. Country Club require rnor e water. Tidewater Oil Cornpany DuPont Corripany The newly constructed refinery of the Tidewater Oil Company The E. I. DuPont de Nernour s Cornpany de r ivea water f'r orn both near Delaware City will be a rriajo r user of both ground, and surface ground and surface sources to supply its widely scattered plants, water when placed in full-scale operation. The anticipated use of laboratories, and office buildings. The prgrnents plant at EdgeIIloor brackish water for cooling purposes will be as rriuch as 396 rngd f'r orn pUIIlpS 24. 0 mgd of brackish water f'r orn the Delaware River for cool the IIlOUth of Cedar Creek. An intensive investigation of the Tidewater ing. Fresh water is supplied to this plant by the General Waterworks property was rnade in which rno r e than 60 test holes and wells were Corporation. The ptgrnent s plant at Newport uses h 5 mgd of brack drilled in an effort to locate sufficient quantities of ground water. ish water for cooling purposes f r orri the Christina River, whereas In addition, 110 foundation tests were made which added to the geo wells provide afresh-water supply. It is e strmated that a daily aver logic knowledge of the area, as well as to the engineering knowledge age of 133, 000 gallons is pumped fr orn wells Cc34-l3, -14, -15, and of the surficial mate r ials , Most of these wells and tests are shown -16 for general use. in figures in Vol. n. AB a result of the investigation the following pro duction wells were drilled and tested: Dc4l-4, 42-6, 51-7, 51-8, The expe r irnental station on Brandywine Creek used 2.02 mgd 52-24, Eb15-4, Ec12-20, 13-6, and 13-11. Using the reported yield fr orn the creek for air - conditioning during a three - month period of these wells when tested, the total yield for 9 wells would be 4, 550 ending about mid - August. Water used for the Louviers Building gallons per minute which would produce nearly 6. 6 rrri.Ilion gallons at Milford Crossroads is pumped fr orn White Clay Creek and aver a day. Total ground water pumped during the year was 110 million aged O. 1 mgd in 1955. Water used by other units of the DuPont gallons. with 87.5 rnl.Ilion gallons pumped in the last 3 months of Company generally are supplied by mum cipa l or privately - owned 1955 when aquifer tests were being made, water s yaterna, Ri chrnond Radiator Company Ludlow Manufacturing and Sales Company , This company, on the Delaware River, 1 1/2 rni le s northeast of This cOIIlpany is located between the DuPont Prgrnents plant and New Castle, uses both surface and ground water. Like other indus the Delaware Power and Light p1ant at EdgeIIloor. This company tries along the river, this company uses brackish water for cooling pUIIlpS an e s ti.rriat.ed 93.6 thousand gallons of water daily fr orn wells purposes. Ground water derived fr om one well, Cd52-l2, is used Cd15-l and -2. In addition, fire-protection facilities for pumping principally for air-conditioning. water f'r orn the Delaware River have been mamtained, Hercules Powder Company Doeskin Products Company This cOIIlpany uses a total of 1. 06 mgd fr om 2 sources. About The Doeskin Products Corripany at Rockland uses 2.88 mgd of 860, 000 gallons are pumped daily f rom Red Clay Creek for cooling water f'r orn Brandywine Creek, rnarnly for washing and cooling. I:n condensers inpilot-plantoperations. An average of 197,380 gallons addition, one well, provides an e stdrnated 10,000 gallons a day for a day is purriped fr orn wells Bc52-2, -8, -9, -10, -13, -14, -15, -17, sanitary purposes. -18, -19, -20, and -23. Numerous other wells and test holes are are listed in a table in Vol. n, and their locations are shown ina fig INSTITUTIONAL WATER SYSTEMS ure in Vol. n. Production of ground water totaled 72.0 rni.Ilion gallons in 1955, which was 10.5 rrrikldon gallons less than that pUIIlp Delaware State Hospital ed in 1954. This reduction was due to the installation of cooling towers on air - conditioning equipment in April 1955. The highest monthly pUIIlpage was 7.08 rni.Ilion gallons in March and the lowest The Delaware State Hospital at Farnhurst derives IIlOSt of its water frOIIl 2 wells, Cd4l-l and -2. Wells and test holes on the 184 185 hospital grounds are shown in a figure in Vol. II. The estimated stock and for irrigation is probably the next largest use. It is noted production from these wells averaged 8.3 million gallons a month that although irrigation use in 1955 totaled 165 tnillion gallons for during 1955. In addition to this ground - water source, water may New Castle County (Dr. R. O. Bausman, Agronotnist, Univ. of Del be supplied by the Artesian Water Company which has a connection aware, personal communication) relatively little water was used in to the system. Owing to increasing water needs and partial failure the area covered by this report. Commercial use, as in restaurants, of one producing well, investigations for additional well sites have gasoline stations, and motels, together with water used by stnall been made in recent years and a site wh ere a moderate capacity institutions, as schools, churches, and others, probably are the well probably could be drilled was found. Additional storage facilities least significant part of the total. have been constructed recently. On the basis of a comprehensive well canvass of the rural area New Castle County Airport around Newark, made in 1951-52, it is estimated that there are more than 2,000 wells in the Coastal Plain of northern Delaware. About 60 percent get their water from the Pleistocene deposits, 35 percent The New Castle County Airport produces water from wells Cc45 from the nonmarine Cretaceous sediments, and 5 percent from ma 1, -2, and 55-1 drilled along Basin Road near Wilmington Manor. A rine Cretaceous sediments. On the basis of the number of houses total of 99. 7 million gallons was pumped from these wells in 1955. shown on topographic maps, it is estimated that there are about A maximum of 10.5 million gallons was pumped in July and a tnin 3, 300 wells and developed springs in the Piedmont of norther.n Dela irnum of 6. 1 million gallons was pumped in November. Most of the ware. Of these wells and springs, about 1,700 are in the Wissahic water is treated to remove iron before use. kon formation, 1,300 are in the gabbro, 50 are in the granodiorite, 150 are in the Cockeysville marble and 120 are in the Bryn Mawr(?) Governor Bacon Health Center gravel. Thus, almost 6,000 wells and developed springs supply water for the rural needs of northern Delaware. The Governor Bacon Health Center at Delaware City is supplied About 32,000 people are not supplied with water from municipal by 7 wells. Most of the water is derived from wells Ec 15-3, -4, and or private water systems. If the per capita use of water is 100 gal 25-1. Other wells, ,Ec15-6, -7, -8, and -9, usedas reserve sources, lons per day, the total rural use of water in northern Delaware is are not used regularly owing to the high iron content of the water. about 3 mgd. The estimates of rural use given in table 31 were ob During 1955, 31. 7 tnillion gallons was pumped from the well field. tained by prorating the estimated total use according to the estima A maximum of 3. 65 million gallons was pumped in August and a min ted number of wells and springs tapping the aquifer. imum of 2. 07 tnillion gallons was pumped in April . Other Institutions Other institutions, generally using limited quantities of ground water, are to be found in the tables of well descriptions (see Vol. II). In this group are schools, churches, welfa~ehomes, penal institu tions, and others of sitnilar nature. Water use by these small users has been included in the estimate under rural supplies in table 31. RURAL WATER SUPPLIES Rural water supplies are generally described as those small individual systems which provide water for homes, farms, COtnrner cial establishm.ents, and small institutions which are outside of areas supplied bywater companies. The purposes for which these supplies are used are many and varied. Most of the rural water is for every day household use, dr;nking, cooking, washing, scrubbing, sprin kling lawns, and so forth. Farm use, including water used by live- 187 186 POTENTIAL DEVELOPMENT By W. C. Rasmussen and R. O. R. Martin The limit of pos sible potential development of fresh-water sup plies would be the total rainfall minus the losses due to evaporation and seepage. Any development approaching this limit would depend entirely upon the economics of the situation. The problem, there fore, resolves to how much can one afford to spend on a water-supply development at one site in lieu of developing a supplymore cheaply at an alternate site. The practicable extent of potential development, cannot be close ly defined because of the important role played by economics. The physical limitation of the amount of water available as well as the cost of storage dams often may be outweighed by choice of an alter nate water-supply having alower delivered cost per unit. The seem ingly remote possibility, for example, of tapping the Susquehanna River as a source of fresh surface water for notrthe rn Delaware per C'"!C'"l co r-HD e-:~~~c'; haps maybe economically more feasible than an extensive dam build ~N-.:t.... ing program on small drainage baeins within the area. (~(.~c~~~ o ~.J.• ::t ..... co Estimates of the amount of potential development necessarily CJ t-l N cover a wide range depending upon how conservative or how expan sive the estimator's viewpoint may be. For northern Delaware the In..-l"" C"l C"l N eO C"'l ,..: authors consider anestimate of the potential development of both .. u ... surface and ground fresh-water supplies of 170 mgd to be conser vative and an estimate of 300 mgd to lie expansive, (see tables 32 (0(0_11"'1 N and 33 and page 195). These estimates, in contrast to the 72 rngd ~ O~~(.;~ .; 000 ..... fresh-water use in 1955 (see p, 171) gives ratios to development of ... '" 2 to 1 and 4 to 1 respectively. ",.,0 The potential development of the brackish-water in the Delaware il ~ 0 N ..... MNc::) V'l N ~~,;, ~ii,ii~ 0 \D River is practically boundless, providing pollution of the river can ..'" ...... '" ~ ... be controlled. Pollution is discussed in a preceding section "Dela '" ware River" (p. 144). ... o The 37 mgd from public water supplies now consumed by New ..15 ... ~ ... Castle County's quarter of a million residents living north of the lil .. a Chesapeake It Delaware Canal in 1955, gives da.ilr consumption ~ per capita of 148 gallons. In comparison the daily consumption per capita in Baltimore, Md., in 1953 was 162 gallons; in Washington, ~ D. C. in 1955 was 158 gallons; and for the Nation was 145 gallons B.. in 1950 (MacKichan, 1951). Such comparisons indicate that the daily .!: ~ use per capita in northern Delaware is in line with other and even .. larger regions. From past experience we can expect this unit con ..o sumption to increase gradually, and furthermore, the population may ..II'" be expected to increase and may even double within 25 or 30 years. Such incr eas e s in both population and in unit consumption will require 189 188 comprehensive, sound, long-range planning to meet the critical wa The potential development depends largely on the use of storage ter problems of the future. reservoirs to increase the safe yield of the developed stream. The final selection of a reservoir should be based onfurther analysis of The actual development of fresh-water supplies in northern Dela streamflow records in this and adjacent areas, and upon pertinent ware as well as being limited in part by the market value of water, economic considerations. will be even more affected by the foresight of the statesmen, finan ciers, and engineers who control public and industrial works, and Considering the 5 streams treated in this report (see table 8. who do the large-scale and long-range planning. Natural conditions in pocket) storage data on required frequency indicate that, with of flow, and other factors, such as, transportation, labor, and real storage greater than 2 mg per square mile, Red Clay Creek would estate values will also impose a constraint on where and how devel provide the highest allowable draft in mgd per square mile (for a opment will be made. 2-year, 5-year or 10-year recurrence~~~terval.)This table also indicates, that under the aame conditiorrt,J;tfstorage per square mile The effect of surface-water storage increments can be visualiz Brandywine Creek would be second to Red Clay Creek in unit yield ed in table 32, which presents a comparison based on relative val (mgd per sq mil, but that, without storage Brandywine Creek unit ues. In general, it was found, approximately, that in order to dou yield would be greater than Red Clay Creek. When planning storage ble the present allowable draft of surface water requires a storage developments the fact that unit yield does not represent total flow of 3 mgsm but to triple the present allowable draft requires 30 mgsm until multiplied by the size of the drainage basin should not be over (or 10 times the storage required to double the present allowable looked. draft). Under present conditions of practically no storage about 15 percent of the mean annual flow of the gaged at r e ams can be utilized; All 5 stream basins listed in table 8 (in pocket), namely, Shell 3 mgdsm storage would make available about one quarter of the mean pot, Brandywine, Red Clay, White Clay. and Christina drain Pied annual flow; and 30 mgdsm storage would permit use of about half of mont physiography and hence are more suitable for surface-water the mean annual flow. storage development than for ground-water development. The south ern half of the report area in the Coastal Plain physiography, how SURFACE WATER ever, is better adapted to ground-water development because of the flat topography and porous sandy soil. Supplementary small reser voirs could provide recharge to the aquifers and thus increase Surface water provides the greatest part of the water currently ground-water yield. used in northern Delaware and also h~ldsthe greatest promise for additional development.- The extent of the development will depend The two estimates of potential development of surface water in upon the storage facilities planned and constructed, and undoubtedly, northern Delaware, compared to 1955 use presented in table 32 a.re the additional water will be more costly than most of the water now based upon tables 5 and 8 and on the curves presented in the section supplied. As a considerable part of the drainage area of some of "Evaluation by basins". The flow to be expected (at a 10-year re the streams considered in the estimates set forth below, lies out currence interval) was developed from records adjusted to 57-year side the State of Delaware, the use of water from such out-of-State base period(1896-1952) onb&iis of long-term stre~owinadjacent areas may involve legal questions not considered in this analysis of states. the physical potential. Brandywine Creek has been compared with Gunpowder Falls, the principal source of water supply for the City of Baltimore, (Whit At present northern Delaware has practically no storage except man, Requa rdt, and Associates, 1956, p. 21) on thebasis of storage. for the 2,040 total capacity in Hoopes Reservoir (on a tributary to "safe yield" and present utilization. The streams are comparable Red Clay Greek but used to supplement the Brandywine Creek supply), in size (Brandywine Creek 314 sq mi, Gunpowder Falls 303 sq mi ] 40 mg capacity in Smaileys Pond (below gaging station on Christina and have similar drainage-basin characteristics. Storage capacity River basin), and an estimated 100 mg capacity in Bellevue Reservoir .on Brandywine Creek is 2, 040 mg (27 percent of the mean flow) and (Stoney Creek basin north of Wilmington). The Brandywine Valley on Gunpowder Falls, 36. 600 mg (56 percent of the mean flow). Association (Wilmington, Delaware) has proposed four reservoirs on Brandywine Creek whose individual capacities would exceed Similar studies compared Red Clay and White Clay Creeks in 1,400 mg. The construction of only two of the proposed reservoirs combination, and Christina River. and found each to utilize only a. would more than double the present storage for the entire region bout 10 percent of the mean flow (Whitman, Requardt, and Associ and greatly minimize the need for additional storage on other ates. 1956, table 18, p. 27). streams. 191 190 Development of large-scale storage facilities, which might uti Table 33.--Estirnated recharge to aquifers in northern lize 50 to 75 percent of the mean flow, may not be economically Delaware and portions recoverable by pumping feasible at many places in northern Delaware because of high real of wells. estate valuation. Other sources, such as, the Susquehanna River, Big Elk Creek" Little Elk Creek, and the Delaware River above Estimated portion tidal effect also should be considered in planning for the future. of recharge avail The use of the Susquehanna River water, however, may be pre Estimated able to wells in empted by Baltimore and other users and any utilization of out-of Aquifer recharge addition to present State waters would pose interstate water problems. The Delaware pumpage River, however, is a source upon which Delaware has asserted a (mgd) (mgd)_ claim to its fair proportion of the water and it may be practicable for users in Delaware to pipe water from fresh-water portions of l'IEmmIT the Delaware River above Trenton, N. J. should the need arise. Cocl.eysville marble 1, 0.2 Uissailickon fonnation 23 2.3 Nature provides northern Delaware with a supply of surface wa GaC;';ro '/ .6 ter sufficient to double the present rate of use if storage of 3 mg per Granodiorite 1 .1 sq mi is provided or to triple the present rate of use by providing a lliocene (?) series 3 .5 storage of 30 mg per sq mi. The key to the situation is long-range planning in order to make the best use of the available water re COASTALPU.W sources. NOl~,mrineCretaceous Lower aquifer 16 4.3 GROUND WATER NiddJ.e aquifer 14 4.0 Upper aquifer 6 1.9 Transitional Cretaceous Under natural conditions, recharge to an aquifer is balanced by l~gothyfonnation 2 .4 discharge. If water is pumped from an aquifer this water is taken l-la-rine Cretaceous from storage unless it is balanced by adecrease in natural discharge, Uenonah sand 4 .7 or an increase in recharge, or a combination of both. In northern Mount Laurel sand. 1 .1 Delaware recharge to the aquifers is Il)ostly discharged into streams and Navesink rwarl crossing the outcrop areas although some water flows downdip to Red Bank sand 4 .4 pass out of the area or discharges into other aquifers. Thus the re ~leistoceneseries 27 8.4 charge to the aquifers of northern Delaware is, in a sense, a mea sure of the potential development of ground-water supplies. For Total 110 24 this reason an attempt was made to estimate the recharge to each aquifer. Admittedly, the rating is qualitative, although it results in a quantitative approximation. sorting, and siltiness with those of the Pleistocene series. The recharge estimates for the aquifer'S are given in table 33 However, only a portion of this recharge is recoverable by pump and were determined by multiplying the average amount of precip ing from wells without damage to other users, - or withoutexhorbi itation on the outcrop area of each aquifer by a "percent of infiltra tant expense to operate wells of low capacity or wells in undesirable tion" for each aquifer. The average amount of precipitation on the locations. Table 33 gives conservative estimates, by aquifer, of outcrop area was calculated by multiplying the average precipita that portion of the recharge that would be available to wells in addi tion in northern Delaware (44. 1 inches per year of 2. 13 mgd per tion to the quantities now pumped. The estimate of total recover- . square mile) by the area of outcrop as measured by planimeter from ability range from 10 to 50 percent for the different aquifers and are the geologic map. The "percent of infiltration" for the Pleistocene based on the writer's judgment in the light of all available data. series was estimated to be 50 percent and was based on a compre When compared to present use, they indicate that the additional hensive water-budget study in the Beaverdam Creek basin near Salis available ground-water in northern Delawa-re is somewhat more than bury, Md. ,5 to 15 miles south of the Delaware State line (Rasmussen twice the present uae, and Sl aughte r , 1955, p. 126). The "percent of infiltration" for each of the other aquifers was estimated by comparing its grain size, 193 19Z This estimate is conservative and does not take into account fac the contamination and pollution of the river and its estuary so that tors, some economic and some hydrologic, that would tend to in .their capacity to absorb and dilute wastes is not exceeded. crease the estimate. For example, the value of water may increase and it may be economical to develop more extensive well fields and less productive wells than are contemplated in the e atdrna.te, given in table 33. Lowering the water. table by pumping will tend to in crease infiltration in some areas, and, hence, increase recharge and decrease losses by evapotranspiration. Works for recharging aquifers artificially have been successful in many places. Surface water, such as flood runoff that is not easily stored or developed by other means, may be used for recharging the aquifers through a system of basins or canals. Thus it may be possible to pump not less than twice and perhaps as much as five times as much water from the aquifers of northern Delaware as was pumped in 1955. Againit shouldbe pointed out thatthese estimates are extremely rough and should be revised as additional data become available. SALINE-WATER RESERVE The lower segments of the Delaware River and the tidal portions ofits tributaries form alarge saline-water reserve of limited utility. U. in the future,it becomes feasible to convert saline water tofresh water economically, many of the problems that accompany water shortages in northern Delaware should be greatly alleviated, if not completely eliminated. However, the Third Annual Report of the Secretary of the Interior on Saline Water Conversion, (McKay, 1955) states: The work accomplished so far indicates that attainment of the first goal of winning fresh water from sea water at a price which municipal users and some industries might pay, and the conversion of brackish water to irrigation uses, seems to be in sight, although much work will be necessary before either can be brought to realization. The task of converting sea water for irrigation is more difficult but the researches continually pro duce new ideas and one of these may well point a way to attain ment, and it is clear that low cost non conventional energy must be developed. Regardless of the outcome of the saline-water-conversion pro gram, the Delaware River and the tidal estuaries will continue to provide brackish water for large-scale cooling and low-quality wash ing processes, for the power, steel-making, chemical, oil-refining, and similar industries. It will also continue to function as the main outfall for undesirable effluents produced in industrial processes. The large volume of the Delaware River, and the brackish tidal in flow combine to dilute the effluents to the point where they generally are not objectionable. Nevertheless, care must be taken to control 195 194 CONCLUSIONS The contrast in cost should be considered as well as the r eapec-. tive utility of surface water with ground water. Larger quantities of surface water are available, but in most cases carry suspended It is concluded that northern Delaware has adequate reserves of sediment, which requires removal by means of flocculation and fiJ;. fresh surface water and ground water to permit at reasonable cost tration. Such quality-control processes require settling basins, an expansion to slightly more than twice the 1955 fresh-water demand, treatment plants, maintenance employees, chemists., and sanitary that is, to about 175 mgd, At considerably greater expense and engineers. Moreover, owing to the fact that some surface streams effort it may be feasible to provide a supply of about 325 mgd or a are used also to transport sewage, chlorination and bacterial anal bout four times the 1955 rate of use. The major key to reaching yses are necessary for. most uses. Ground-water wells, on the either of these goals is additional surface-water storage, that is, other hand, can be sealed to prevent pollution, and more often than several moderately-sized reservoirs, similar to the Hoopes Res not produce a pure water at constant temperature and of such good ervoir, at strategic sites in the valleys of the Christina River sys quality that it requires little or no treatment and only a relatively tern, Possibly some of these new reservoirs may have to be out nominal work force of pump operators. The cost of drilling well side the State of Delaware. fields is usually cheaper than that of building surface reservoirs for limited water supplies, at least up to a moderate operational There appear to be readily available, additional ground-water and economical limit. For the greater demands the treatm.ent cost reserves equal to about twice the 1955 rate of use, that is, to about per unit of surface water decreases, whereas the cost of the system 25 mgd. More intensive and more expensive development might for collecting ground water from numerous wells increases. Beyond obtain additional water bringing the total ground water ava,ilable an economical limit, therefore, which differs by locality, purified (including present use) to about 50 rngd, Owing to the diffiruIties surface water may be cheaper per unit than ground water. Each inherent in charting accurately the channel-type aands , which yield type of source has its distinct value, however, and both are needed the larger quantities of ground water in the Coastal Plain of north for well balanced water-resources development in northern Delaware. ern Delaware, adequate testing programs should precede any large developments. The danger of salt-water encroachment to most of the aquifers in northern Delaware is ever-present, because half the perimeter of the area is bounded by brackish waters, the Delaware River and the Chesapeake and Delaware Canal. putpost wells as watch points behind the intake belt of these aquifers will detect salt-water intru sion when it first occurs. Detailed hydrologic analysis will be an increasing need, in order to determine pumping rates that will ad just ground-water withdrawal to recharge without increasing salt water encroachment. The saline-water reserve, in the Delaware River and in the trib utary estuaries, is regarded as abundant to fulfill all foreseeable needs of industry for low-quality processing and cooling water of this type. Therefore, it may be seen that considerable additional develop ment of water supplies in northern Delaware is possible, but will be limited principally by the ratio of the cost of water supply to the market value of pure water. Hydrologic conditions and such market factors as transportation, labor, and real estate impose a constraint upon where and howdevelopments cari b e made. The general hydro logic conditions in the report area indicate an optimistic outlook as to potential water supply. As the demand for water increases, de velopment should likewise proceed in a sound and conservative man ner. 197 196 REFERENCES REFERENCES--Continued. Andreasen, G. E., 1953, Chapter on Delaware in Water levels and Cloos, Ernst, and Hietanan, Anna, 1941, Geology of the "Martie artesian pressures in observation wells in the United States in Overthrust" and the Glenarm series in Pennsylvania and Mary 1950, pt. 1, Northeastern States: U. S. Geol. Survey Water land: Geol. Soc. America Special Paper 35, 193 p. Supply Paper 1165, p, 9-17. Coskery, O. J., 1956, Water levels and artesian pressures inDela Bascom, Florence, Clark, W. B., and others, 1909, U. S. Geol. ware, 1955: Delaware Geol. Survey Water-Level Rept. 4, 9 p, Survey Geol. Atlas, Philadelphia folio (no. 162). Coskery, O.J., andBoggess, D.H., 1956, Water levels andartesian Bascom, Florence, and Miller, B. L., 1920, U. S. Geol. Survey pressures in Delaware, 1954: Delaware Geo1. Survey Water Geol. Atlas, Elkton-Wilmington folio (no. 211). Level Rept. 3, 10 p, Bascom, Florence, and Stose, G. W., 1932, U. S. Geol. Survey Durfor, C. N., and Keighton, W. B., 1954, Chemical characteristics Geol. Atlas, Coatesville-Westchester folio (no. 223). of Delaware River water, Trenton, New Jersey, to Marcus Hook, Pennsylvania: U. S. Geol. Survey Water -Supply Paper 1262, Beamer, N.H., 1953, Chemical character of surface water inPenn 173 p, sylvania 1949 to 1951: Pennsylvania Dept. CommerceSt.atePlan. Board Pub. 26, 96 p, Eardley, A. J., 1951, Structural geology of North America, New York, Harper and Brothers. Bennison, E. W., 1947, Ground water--Its deve loprnent, uses, and conservation, St. Paul, Minn., Edward E. Johnson. Fair, G. M., and Geyer, J. C., 1954, Water supply and waste-water disposal, New York, John Wiley and Sons, Inc; , 973 p, Boggess, D. H., and Coskery, O. J., 1955, Water levels and artesian pressures in Delaware, 1953: Delaware Geol. Survey Water Ferris, J.G., 1949, Ground Water in Wisler, C.O., and Brater, E. Level Rept. no. 2, 10 p. F., Hydrology, New York, Jo~Wileyand Sons, Inc ,, p. 247- 259. Brown, R. H. 1953, Selected procedur.es for analyzing aquifer-test data: Am. Water Works Assoc. Jour ,, v.45, p, 884-866. Fireman, Milton, and Hayward, H. E., 1955, Irrigation water and saline and alkali soils in Yearbook of Agriculture, 1955: U. S. California Water Pollution Control Board, 1952, Water quality cri Dept. Agr., p. 322-32'6.'" teria: State Water Pollution Control Board Pub. 3, Sacramento. Groot, J. J., 1955, Sedimentary petrology of the Cretaceous sedi Campbell, M. R., and Bascom, Florence, 1933, Origin and struct ments of northern Delaware in relation to paleogeographic prob ure of the Pensauken gravel: Am. Jour. Sci., -5th ser., v , 26, lems: Delaware Geol. Survey Bull. 5, 157 p. p, 300-318. Groot, J. J., Organist, D. M., and Richards, H. G., 1954, Marine Carter, C. W., 1937, The Upper Cretaceous deposits of the Chesa Upper Cretaceous formations of the Chesapeake and Delaware peake and Delaware Canal of Maryland and Delaware: Maryland Canal: Delaware Geol. Survey Bull. 3, 64 p, Geol. Survey, v , 13, p, 237-281. Groot, J. J., and Rasmussen, W. C., 1954, Geology and ground Chester, F. D., 1884, Preliminary notes on the geology of Dela water resources of the Newark area, Delaware: Delaware Geol. ware--Laurentian, Paleozoic, and Cretaceous area:Pniladelphia Survey Bull. 2, 123 p, Acad. Nat. Sci. Proc., p, 237-261, 1 pl. Grover, N. C., and Harrington, A. W., 1943, Stream flow, New Clark, W. B., Bibbens, A. B., and Berry, E. W., 1911, The Lower York, John Wiley and Sons, Inc. Cretaceous deposits of Maryland: Maryland Geol. Survey, 622 p , 199 198 REFERENCES- -Continued. REFERENCES--Continued. Henderson, Oliver, 1951, Chlorides in shallow well supply: Mary Marine, I. W., and Rasmussen, W. C., 1954, chapter on Delaware land ..Delaware Water andSewage Assoc. P'roc; , 24th Ann. ConL, in Water levels and artesian pressures in observation wells in p, 6-7. the United States in 1951, pt. 1, NortheasternStates: U. S. Geol. Survey Water-Supply Paper·1l91. Hulme, A. E., 1954, Surface-water resources in Groot, J. J., and Rasmussen, W. C., Geology and ground-wat;"i- resources of the Marine, I. W., and Rasmussen, W. C., 1955, Preliminary report on Newark area, Delaware: Delaware Geok, Survey Bull. 2, p. the geology and ground-water resources of Delaware: Delaware 125-132. ' Geol. Survey Bull. 4. Kaplovsky, A. J., 1950-1955, First annual report of the Water Pol McKay, Douglas, 1955, Third annual report of the Secretary of the lution Commission, Dover, Delaware; also, 1951-1955, Zd, 3d, Interior on saline-water conversion: U. S. Dept. Interior, 125 p, 4th, 5th, 6th Ann. Repts. Mebus, G. B., 1955, Report to the Public Service Commission of _____ ...,1952, A study of the accumulation and distribution ofiron Delaware on water companies in New Castle County, Glenside, waste discharges within the Delaware River attributed to dis Pennsylvania, George B. Mebus, Inc. dupl , r ept; , 16 p, charges originating within the State of Delaware: Dover, Dela ware Water Pollution Comm., mimeo. rept. Meinzer, O. E., 1923, Outline of ground-water hydrology, with def initions: U. S. Geol. Survey Water-Supply Paper 494, 71 p, _____ ,..1954, A comprehensive study of pollution and its effect editor, 1942, Hydrology: v , 9 in Physics of Earth series, upon the waters within the Brandywine Creek drainage basin: ----;:N';"e-w"""""";Y;:'o-rk,McGraw-Hill Book cs.. Inc., 712 p, Dover, Delaware Water Pollution Ccmm; , 112 p, Meinzer, O. E., and Stearns, N. D., 1929, A study of ground water Keilhack, K., 1935, Grundwasser undQuellenkunde, Berlin, Gebru in the Pomperaug Basin, Conn. with special referenc.e to intake del' Borntraeger, 3d ed, and discharge: U. S. Geol. Survey Water-Supply Paper 597-B, p. 73-146. Leopold, L. B. ,and Maddock, Thomas,. Jr. , 1954, The flood control controversy, New York, Ronald Press, 278 p. Murphy, E. C., 1904, Accuracy of stream measurements: U. S. Geol. Survey Water-Supply Paper 95, 169 p, Lineweaver, G. W., 1952, Demineralization of saline waters, apr~ Murphy, E. C., Hoyt, J. C., and Hollister, G. B., 1904, Hydro liminary discussion of a research program with an outline de graphic manual of the U. S. Geol. Survey: U. S. Geol. Survey scription of potential processes and a bibliography: Washington Water-Supply Paper 94, 76 p, D. C., U. S. Dept. Interior dupl , rept., 66 p, Pearson, V. L., Jr., and Behn, V. G., 1956, General hydrological Lunz, G. R., Jr., 1938, Effects of flooding of the Santee River in studies of the State of Delaware: Rept, W-l, Civil Eng. Dept. ',April, 1936, on oysters in the Cape Romain area of South Car and Eng. Experimental Sta., Univ. Delaware, Newark, 77 p. olina, Pt. IT: War Dept;, U. S. Corps Engineers, Charleston, South Carolina. Pennsylvania Water Supply Commission, 1917, Gazetteer of streams: Water resources inventory r eptr , pt. 3, 657 p, MacKichan, K. A., 1951,Estimated use of water in the United States: U. S. Geol. Survey Cire. 115, 13 p, Rasmussen, W. C., and Andreasen, G. E., 1957, A hydrologic budg et of the Beaverdam Creek basin, Maryland: U. S. Geol.Survey Marine, I. W., 1954, Water levels and artesian pressures in Dela Water-Supply Paper, in press. ware in 1952: Delaware Geol. Survey Water-Level Rept. no. 1, 11 p, Raarnne sen, W. C., and Beamer, N. H., 1956, Wells for the obser vation of chlorides and water levels in aquife ra w~ch cross the Chesa.'peake..and Delaware Canal: U. S. Geol. Survey. -operr-Hle report. zoo 201 REFERENCES - -Continued. REFERENCES- -Continued. Rasmussen, W. C., and Slaughter, T. H., 1955, The water re Wenzel, L. K., 1942, Methods of determining permeability of water sources of Somerset. Wicomico and Worcester counties: Dept. bearing materials, with special reference to discharging-well of Geology, Mines and Water Resources Bull. 16. methods: U.S. Geol. Survey Water-Supply Paper 887. Rippl, W., 1883, The capacity of storage-reservoirs for water sup Whitman, Requardt, and associates, 1956, Report to the Levy Court ply: Proc. Inst. Civ. Eng. (Great Britain), v , 71, p, 270-278, of New Castle County on water supplies in New Castle County, 290. Baltimore, 34 p, Smith, H. V., Cammack, Margaret, and Foster, E. 0., 1936, Mot Wilcox, L. V., 1948, Explanation and interpretation of analyses of tled enamel in the Salt valley and the fluorine content of the water irrigation waters: U. S. Dept. Agr. Circ. 784, 8 p, supplies: Arizona Agr. Exper. Sta., Tech. Bull. 61, 1936. Wisler, C. 0., and Brater, E. F., 1949, Hydrology, New York, Spicer, H. C., McCullough, R. A., and Mack, F. K•• 1955, A search John Wiley and sons, Inc., 419 p, for aquifers of sand and gravel by electrical resistivity methods in north - central New Castle County, Delaware: U. S. Geol , Wolman, M. G., 1955, The natural channel of Brandywine Creek, Survey open-file report. Pennsylvania: U. S. Geol. Survey Prof. Paper 271, 56 p. Theis, C. V., 1935, The relation between the lowering of the piezo Worrilow, G. M. , and others, 1955, Water in Delaware, a prelimi metric surface and the rate and duration of discharge of a well nary report: Delaware water resources study committee, Newark, using ground - water storage: Am. Geophys. Union Trans., p, mimeo. rept., 69 p, 519-524. Thomas, H. E •• 1951, Conservation of ground water, New York, McGraw-Hill Book Co., Inc. Tolman, C. F., 19.37, Ground water, N.ew York, McGraw-Hill Book ce., Inc, , 593 p. Trewartha, G. T., 1943, An introQuction to weather and climate, New York, McGraw-Hill Book Co. U. S. Geo l, Survey, 1956, Surface water supply of the UnitedStates, 1953: Pt. l-B North Atlantic Slope Basins, New York to York River, U. S. Geol. Survey Water-Supply Paper 1272, 535 p, - U. S. Public Health Service, 1946, Drinking water standards: Public Health Reports, v , 61, p. 11 (Reprint no. 2697). Vermeule, C. C., 1894, Water supply: New Jersey Geol. Survey, Ann. rept. of State Geologist, v; 3, 448 p. Ward, R. F., 1956, ThegeologyoftheWissahickonformationinDel aware: open-file report, U. S. Geol. Survey, 59 p. Waring, F. H., 1951, Nitrates in water and their relationship to methemoglobinemia: Univ. Michigan, In-service training course in waterworks problems. 203 202 PROBLEMS OF WATER MANAGEMENT fields of engineering, chemistry, geography, topography, and geology. What changes need be made, if any, cannot be By Vaughn C. Behn determined until such an investigation has been made. Aquantitative estimate of current water usage in northern Dela Basic data and their interpretation relative to avaUable water ware has been presented previously in this report. There remains, resources have been presented in the previous sections of this report. nevertheless, the requirement as to "the uses to which the water is This information provides a foundation upon which plans for the man to be put in the foreseeable future. " agement of the water resources of the area may be based. In this section an attemptis made to describe the procedures and problems The "foreseeable. future" must be selected as some fixed number associated with the evolution of such plans. of years. During the past, many cities in their rapid growth period have found it necessary to enlarge their supplies every two6rthree As a matter of convenience, these procedures and problems' are decades. In addition, a 10...30 year lag from inception of a project discussed in terms of (a) water requirements, (b) development of to completion of the construction has not been uncommon. As a water sources, (c) water treatment and distribution, and (d) finan result, attempts are usually made to forecast water requirements cial and legal aspects. These topics are selected because they indi 30-50 years in the future. cate the nature of the phases to be explored in establishing water management plans. Such a forecast has been made by Whitman, Requardt and As so ciates ( 1956) for the Levy Court of New Castle County. They an WhUe this section deals with the usage of water resources from ticipate that the population of northern New Castle County (including the supply viewpoint, this should not be construed as an attempt to Wilmington) will increase from approximately Z50,000 in 1955 to minimize the value of our water resources for other purposes. As 500,000 in ZOOO. This will be associated with an increase inthe noted by the Delaware Water Resources Study Committee (1955), the average yearly public water consumption from 37 million gallon.pej maximum beneficial use of water requires consideration of such day in 1955 to 80 million .gallonsper day in ZOOO. The peak rate of needs as recreation, waste disposal, drainage, hydroelectric power, usage of public waters is estimated to be 100 million gallons per day and aquatic life as well as sup~ly.However, water supply for do in ZOOO. The allotmentof a peak rate of 100 mgdis made as follows: mestic, agricultural, and industrial purposes usually receives the highest priority, as is typified by the proposed water legislation for 1. Doubling of City of Wilmington demand (to 60mgd).. .. the State of South Carolina (Louisiana j.egislative Council, 1955). Z. Tripling of public suburban surface water demcmd.(toZ8 The following statements are written from the viewpoint of the water mgd) supply needs of northern Delaware with the qualification that final 3. Public ground water consumption in ZOOOat same pro- plans for the management of the water resources of the area should portion to total public supply as in 1955 (to lZ mgd) incorporate all needs. 4. Year ZOOOper capita consumption 160 gallons per day based on yearly average and ZOO gallons per day based WATER REQUIREMENTS on peak rate of summer usage. The projected per capita consumption of 160 gallODS per ~y The need for fundamental information regarding quantities of implies some industrial use of the water •. T~iSfactor does reqUire ~Y.i water required for water-supply needs has been stated by the Lou additional consideration, in the writer I s op~on.Aland use • isiana Legislative CouncU (1955) as follows: which projects into the future might be of cons~erableaid m deter .. mining the extent and requirements of future mdustry. A study in The consensus of opinion of water engineers andother water 1951 of a diver sified industrial area in Baltimore, showed. that 1300 . . d .al 1 d h d a total demand of about ~3 policy experts is that the first step, andone of the most im occupIed acres of m ustrl an a ~ma~=e portant steps, to be taken in the revision of a water policy is million gallons per day (Shehadi et al, 1951). An order of 6 _ 7 mUlion gallons per day per square mile of varIed y to conduct a thorough inves tigation by skilled pe r sonnel of the ...al d d .nfluence the wate:r indicates how qwcklylIldustrl eman can I re-__ existing water resources, the uses to which the water is being . ",.'••-,::":11 put, the uses to which the water is to be put in the foreseeable quirements of an area. future and the standards of quality necessary for such uses. This involves the collection and correlation of quantities of th:n ~:~:~~o~s~:;:sw;:::e:::::;::Dt::vi::;:-. data from the users or potential users of water and in the De:"::::, ":~.i~.il\ Z04 :"""~_l! Delaware Valley Group of the Philadelphia office of the U. S. Army gical Survey, studies along these lines have progressed well in Del Corps of Engineers. This group is currently engaged in a three aware. year study of the water resources of the -Delaware River Basin. Water requirements for all purposes will be projected for the un Ground-water studies as carried on by these groups have as their usual period of 100 years. The goal of this study is to design a ultimate aimthe estimation of the amount of water which can safely comprehensive plan for the most economical development of the be taken from the ground. Little can be added, therefore, to the water resources of the Delaware Basin. estimates which have been reported in previous sections of this re port. As has been shown, some alteration in the basic picture may The Corps of Engineers' activity seems to be an attempt to an occur due to salt-water encroachment. There is also a possibility alyze the water - resources requirements placed on the Delaware that artificial recharge of ground-water supplies, as currently car River by an industrial belt extending from Baltimore to New York. ried on in many parts of the country, could improve the ground-wa As northern Delaware will be located centrally in such a belt, the ter situation. This would require carefully planned experimentation engineer's study should be of great interest to the state. for verification. DEVELOPMENT OF WATER SOURCES Those interested in developing ground - water supplies can be guided by the basic findings reported in the previous sections. Drill ing of one or more test holes and the conduction of a pump test to Northern Delaware is fortunate in having available both surface determine quantity and quality of water may be required in any spe and ground-water sources. There are sound economic reasons for cific instance. the development of ground-water supplies, because they may be ob tained from relatively shallow aquifers, and do not require exten Surface Water sive treatment. In addition, the temperature of the ground water is both lower and more uniform than that of surface water. This is especially important for industry (Powell, 1948). As with ground-water sources, surface water sources may be analyzed to determine the yield of water which maybe expected. One Nevertheless, surface waters must be given consideration since of the major differences is the nature of the basic information re there is a limitation to the amount of ground water available. Both quired. A second major difference is that available storage will of these sources are discus sed below from the viewpoint of estima influence the percentage of the mean flow of a stream which may be ting their availability. developed. The analysis is perhaps best illustrated by a short de scription of the elements of a storage-runoff study. Ground Water The first step in such a study is the extraction of stream flow records which are accumulated by the United States Geological Sur Methods to determine formation constants (coefficients of storage vey in cooperation with the states. Monthly rates of flow from the and transmissability) have greatly contributed to knowledge concern stream flow records are added cumulatively and compared with a ing the safe yield of aquifers. given rate of removal of water (or yield), also added cumulatively. The maximum difference between these two is the amount of storage However, due to the complexity of the geologic formations which required to develop the given yield. For different years of the re are yielding the water, the actual hydraulics of the wells is only a cord different values of storage will be required to develop a cer portion of the picture. The ground water hydrologist finds an under tain yield. This variation oc~ursbecause increased storage to ob standing of the geology of the area essential to his interpretatiou tain a given yield would be required during increasingly dry periods. of the hydraulic data. To this end modern geological and geophysical The assembled data can then be analyzed statistically by the hydrol prospecting techniques originally developed for locating oil serve a ogist to estimate the amount of storage required to develop a cer real need in the discovery of ground-water resources. tain yi~ldexcept perhaps for one year in twenty or, more conserva tively, one year in one hundred. With this basic geologic and hydraulic data some estimate canbe made of the specific amount of water available from a given area. Simultaneous with this analysis, topographic and geologic maps of the area are examined and field studies are made for possible Since the creation of the Delaware Geological Survey in 1951, reservoir sites. Estimates are made of the. amount of storage a and through its cooperative program with the United States Geolo- vailable for different elevations of the dam. The total information 207 206 is then integrated into a plan devised for developing a water supply TABLE 34 from the stream. Storage-yield studies for streams in area of northern Delaware Determining the treatment of the water required and the methods for transmis sdon and distribution of the water complete the technolog Stream Proposed Dam Storage Safe ** Ref. ical aspect of the study. user location rQillion yield &allons) (mgd) Prior .to reporting on specific studies of streams of interest to northern Delaware, attention should be called to the statistical na ZO Albright ture of. this work. Some element of chance is usually undertaken East Branch Chester Wawaset 1.07 in engineering work. The break off point as regards "taking a chance" of At Friel, is usually determined by the economics of the situation. During the Brandywine Inc, 1945 period when many cities were revising their water-supply atruc:turel!J every Z - 3 decades the practice arose of selecting a storage which Octorora Chester Pine Grove* 1.15 ZO " would develop the desired .yieldexcept for one.yaar in twenty. This practice was also to some extent based on the philosophy that each Ridley Creek Chester Red Bridge 8.00 16 " generation should pay .in part lor its own public works. The point is mentioned in passing since many in civil authority might be un West Branch Chester Aston Mills 4. 50 10 " aware of the relation of the technological analysis to the philosophy of Chester of the entire undertaking. Creek One element which interferes with the statistical nature of the Susquehanna Baltimore Conowingo 163 EngL.. neering stupy is the length of term of the stream flow records for the stream River Dam * in question. This is true, unfortunately, in Delaware because only News Record the Brandywine has a continuous record approaching what mightbe 1956 considered satisfactory. Wherever a shortage occurs stream flow records must be extended by comparison with a suitable nearby long time record (American Society of Civil Engineers, 1949). This fac Brandywine Wilmington Hoopes Res- Z.04 73 WhitmaI\ tor detracts from the certainty of the sta$istical analysis and increas River New Castle ervoir * Requardt es the possibility of taking undue risks or of spending moneyunjusti Co. and fiably. Associ ates 1956 Studies of the safe yield of the various streams readily acces sible 104 to northern Delaware have been made by various groups. A compi Brandywine Wilmington Not 5.30 " lation of these is shown in Table 34. The only study for. northern River New Castle specified Delaware ail a whole was made by Whitman, Requazdt, and Associ Co. ates in 1956, although it was reported by Wills in 1931 that s ever al reservoir sites had been investigated for the City of Wilmington. Red. White New Castle Not 1.15 41 " Clay Creeks Co. specified The report by Whitman, Requardt and Associates, suggests, in 30 essence, that a more dynamic part be played by tbe City of Wilm Red AtWhite Wilmington Hoopes Res- 35% of " ington's Hoopes Reservoir. This is quite logical since storage-yield Clay Creeks New Castle ervoir * reser relationships are such that the storage. reservoir when completed Co. voir will not be used as a static reserve for the system, but as a living 4 and active part. At the same time, increased utilization of Red and Christina Delaware Smalley's .040 " White Clay Creeks and the Christina Creek is recommended by the Creek Water Co. Pond creation of additional water-treatmentfacilities of the General Water .080 6 Works Corporation. The increased usage of the Christina Creek is Christina New Castle Not " Co. to be accompanied by storage of ~O million gallons capacity at an Creek specified unspecified location. The immediate increase of usage of waters . *Existing **Allowances not made for diversion rights to other users Z09 Z08 from Red and White Clay Creeks can be accomplished, according to The practical problems associated with water treatment and dis. the report, without storage at this time. Additional devefepment tribution are discussed below. of the water resources of the Red and White Clay Creeks at a later date (1966), may require consideration of storage on these creeks Water Treatment or joint use of Hoopes Reservoir with Wilmington and the General Water Works Corporation. The problems associated with treatment of water in Delaware This report by Whitman, Requardt and Associates has served a are readily solved by current technological knowledge. Ground wa real need in outlining thepossible solution to the increased utiliza ter throughout the state is usually simply subjected to chlorination tion of the surface - water reSO\l.rces readily available to northern and perhaps aeration. Iron removal is required occasionally (Lohr Delaware. The report clearly served the needs of the Levy Court et al, 1953). of New Castle County, which authorized the work. The scope of the report was limited by Levy Court in that matters pertaining to eco Surface waters in the area are almost uniformly subjected to nomics and organizational structure were not to be covered. coagulation with alum, sedimentation, filtration and chlorination (Lohr et al, 1953). Since most of the projected surface supplies For the individual interested in the creationof an overall water are being currently utilized, experience is available to the designer. resources plan, there is one disturbing aspect to the increased know ledge gained from the report. The findings were given considerable Local problems do occasionally appear which cause a justified newspaper space of a favorable nature. (For example see issue of protest from consumers. Taste problems associated with phenolic the Journal Every Evening for April 10, 1956). The possible crea type wastes in the Brandywine and algae in the White and Red Clay tion of public apathy towards the water problem comes at a time Creeks are an example. These are local situations which should when just the opposite is required. The need of an educational pro be remedied by the efforts of the Delaware Water Pollution commis gram for the public support of any water-management plan should sion. This group, through its drainage-basin investigation approach, never be minimized. Lack of support for the undertaking of the has brought about a continuing improvement of Del awar eta streams financing of construction has actually occurred. In one case the (Delaware Water Pollution Commission 1955). lack of public .support has in turn been corrected belatedly by an educational program (Engineering News Record, 1956). One problem as regards water quality which may prove very difficult to solve if it occurs on a large scale, concerns the salt Also, a comprehensive water plan.which envisions Wilmington water encroachment of ground - water supplies along the Delaware. in the central location of a highly industrialized belt running from This was discussed previously under Development of Water Sources, Baltimore to New York would require more thorough analysis than Ground Water. has been published to date. Certainly a full study would explore all sources available to the area, including the Delaware and Susque Water Distribution hanna. The economics of obtaining water from these sources, and the organizational structure required to bring the plan into effect are also key points to be determined. Water distribution is not a complex technological problem. North ern Delaware, however, does present water distribution problems WATER TREATMENT AND DISTRIBUTION which are difficult to solve because of the complex nature of water company ownership in New Castle County. Consideration of the treatment of water and its distribution usu The variety of sour ce s of supply fo r New Castle County consumer s ally follows the selection of the water source, although the degree is iudicated by Table 35 which shows the status of 8uppliers to county of water treatment can influence source selection. consumers. Within Delaware there is sufficient experience to determine the The development of additional water supplies for an. expanding degree of treatment for any need, but the dilstribution presents area has resulted in some rather unique situations as follo.ws: unique problems. The expansion of existing systems requires over lapping of political boundaries and the extension of facilities which 1. Five companies have beenformed to develop well supplies may not have grown originally in a planned fashion. This latter for individual housing developments. phase offers problems in projected planning. Zll Z10 TABLE 35 Continued TABLE 35 Status of water suppliers in New Castle County Sources Consumer Sources Consumer Sedgely Farms Wells Sedgely Farms Water Co. Arden Water Naarnan's Creek Arden and Ardentown Company Wilmington Suburban Water Corp. Willow Run Wells Willow Run Water Co. Artesian Water Principally wells Various in suburban Co. Delaware Water Co. * Wilmington including Various suburban loca Christiana, Mill Creek Wilmington Brandywine (Municipal) tions along main routes and New Castle Hundred from Wilmington Cantwell Wate r Well Odessa Heights Co. Wilmington Bellevue Quarry Brandywine Hundred Suburban Delaware Water Co. * Chester Octorora Wilmington Suburban Water Co. Chester Municipal Municipal Water Co. Collins Park Wells Collins Park * Affiliated with General Water Works Corporation Water Co. Z. One company was established to supply specific housing Delaware Water Christiana Creek Various industries, developments with its source the Delaware Water Company. Co. * White and Red Clay three water companies Creeks and two municipalities 3. The Delaware Water Company, subsidiary of General Wa ter Works Corp., acts in the capacity of wholesaler, sup New Castle Wells Town of New Castle pling municipalities, industries, and private water com (Municipal) panies. 4. Municipal water companies such as Wilmington and Newark New Castle Delaware Water Co. *. Brookside Park and have been expanded to accommodate growing areas outside County Water Co. Wells Chestnut Hill Estates municipality limits. Newark Wells Newark 5. Suburban domestic suppliers such as the Wilmington Sub (Municipal) Delaware Water Co. * urban Water Company and the Artesian Water Company have expanded to meet the needs of Greater Wilmington. These companies together with the Wilmington Municipal Newport Wells Newport Supply are the principal domestic suppliers to the county, (Municipal) Delaware Water Co. * the latter having expanded its municipal service into the county along the main arteries leading from the city. There is a degree of intermingling between these principal sys North Star Wells North Star Water Co. tems. 6. Domestic service is more varied than industrial. Prin cipal industrial suppliers include the Delaware Water Company and the Wilmington Municipal. Z13 ZIZ 7. A large number of private supplies, both domestic and in hundred dollars including 68 cents for school purposes as com dustrial, are taken from the ground. pared to $0.50 per hundred dollars for the county area. Natu rally this difference encourages, to a very great extent, build 8. Almost all readily tapped surface-water supplies in the ing in the county and prevents the extension of city boundaries, county are utilized, but not fully utilized. with a resultant loss of revenue to the city. Criticism is, there fore, frequently voiced against granting aid to suburban commu Oddly enough then, one county consumer may be receiving water nities by the extension of city facilities. which originates in the ground water supplies under his horne, while his not too distant neighbor has surface water from the Susquehanna Voluntary cooperation may be considered the best answer by water shed supplied by way of the Chester Municipal Supply. those who are currently engaged in the business of distributing wa ter. Undoubtedly concrete steps in the direction of a cooperative The problems inherent in such a complex ownership have been program would do much to substantiate the beliefs of those who feel noted by the Delaware Engineering Association (1954). that voluntary methods are sufficient. Failing this some legal de velopment to resolve the problem seems certain. Tl1ese suppliers have developed in haphazard fashion, have intermingled and poorly defined areas of service, different rate FINANCIAL AND LEGAL ASPECTS structures and generally have poor or no interconnection. and The policies of the companies diverge equally in the field of The solution of the technological aspects of a water supply pro expansion for developers and most of the smaller companies have blem leads to the consideration of the financial and legal aspects. come into being because of conflicts in this field. Stated differently, there must be funds available for the construc tion of water supply facilities, and there must be an organizational The first of the above quotations is indicative of circumstances structure to permit the use of the same. one might expect as a function of the area's growth. In the event that northern Delaware were to maintain status quo no serious pro The availability of funds is usually in question because there is blemwould be implied by the current multi-ownership situation. always great competition for public money. Any sponsor of a pub Fortunately, every' indication suggests that the area will continue lic cause is sure to find (upon searching) other causes with other its prosperous growth. Thus the latter quotation indicates a major adherents who regard their goals as no less important. The fact adIninistrative problem. Apparently thJl continued economic expan that public funds are available does not constitute a final solutio.n to sion of the area requires some coordination between the various the water-management problems of an area, because an orgaIllza companies in providing expanded services. tional structure is required to arrange for all phases of the water management from original planning to water use. For the water companies expanded services involve the neces sity of seeking additional water sources and then obtaining the cap Financial Aspects ital required to develop these facilities. Also, the requirement of expanding on a planned basis requires some degree of cooperation as regards integration of supplies. Integration of the various sup The financing of any major new structures f~rw.ater suppl.y in plies has been suggested (Delaware Engineering Association, 1954), northern Delaware is rather difficult to deal Wlth 10 generalized but the manner in which this can proceed is not clear. terms. Some idea of the general magnitude of the costs of water supply projects and of conceivable methods of financing may be of Wills ( 1948) states that by state enactment Wilmington may at interest however. its own discretion supply areas within 10 miles of its boundaries. A coordinated plan for supplying water along three principal feed Development of surface-water sources which have to be tranS er mains from the city has been evolved for suburban consumers. ported some distance may require rather large expenditures. The Nevertheless, this plan specifically includes the sale of water di order of magnitude of such costs is indicated by data taken from a rectly to consumers, thus excluding sale through suburban water report by Albright and Friel, Inc. (1945) and shown in Tab~e36. companies. Wills' comments on the relation of city and suburban consumers are as follows: Table 36 includes construction which has been undertaken in past years and is not meant to suggest a fixed investment cost. Interest The current city tax rate (1948) in Wilmington is $2.07 per inglyenough, however, a more recent water supply projectfor near 214 215 TABLE 36 The expenditure of sums of this magnitude necessitates special consideration of methods of financing. Whitman. Requardt and As Initial cost of developing various surface water sources sociates' recommendations (1956)for expansion of the General Wa ter Works Corporation on the Clay Creeks and the Christina could City Capacity Distance Cost Invest- simply require private capital in contract with the City of Wilming (mgd) of water dollars ment ton. As indicated under the discussici;n of water distribution, pre t~~spott $/mgd sent Wilmington policy is not in accord with such ar-rangement (Wills, miles 1948). Likewise, private capital could and will to some extent be used to further develop surface and ground-water resources of the New York-Croton 315 36 ) area for public supply. ) 551, 000, 000 667,000 New York-Catskill 500 105 ) A second alternative. in default of private enterprise or for other reasons. is that New Castle County may prefer to develop increased New York-Delaware 440 105 280, 000, 000 635,000 water facilities as a governmental function. Precedent for such ac tion lies in the Wilmington-New Castle Sewerage System which was Los Angeles 355 388 176,000,000 495,000 financed by general obligation serial bonds under a joint contract (Wilmington Street and Sewer Dept; , 1955). Boston 320 80 111,200,900 350,000 A third possibility is the creation of a northern Delaware water Albany, N. Y. 32 20 10,000,000 313,000 authority with powers to finance water systems through revenue bonds or a combination of revenue and general obligation bonds. Such an agency is discussed further below. by Chester was estimated at $13, 550, 000 for a 20 million gallons per d~ysupply which must be transported some 35 miles ( F. S. Friel, Legal Aspects 1951), indicating an investment of $678, 000 per million gallons per day of developed supply. This figure is for a completely new source of supply and includes the reservoir, dam, treatment facilities, and Delaware's requirements in the field of water legislation are by transmission to the city. The measures proposed to Levy Court by no means unique. A recent report on 15 southeastern states shows Whitman, Requardt and Associates ( 19;;6) would presumably cost that all but two are actively reviewing water legislation (Louisiana less since they involve existing facilities. Legislative Council. 1955). The writer holds the belief that these problems which. of course, apply to northern Delaware are best Initial investment in ground-water supplies in the northern Del considered from the viewpoint of the state as a whole. aware area would seem to be considerably less than that of the typi cal surface-water supply. Information obtained by the writer would The aims of any legislative program for Delaware have been indicate that a maximum of about $70,000 per million gallon per day clearly stated in an instructive bulletin prepared by Ellis and Baus developed has been invested in two large ground-water systems. man (1955). This cost excludes the distribution system. The figure compares favorably with Geyer's 1945 estimate of $57, OOOper million gallons Some of the overall goals might be to adopt. modify. or continue per day for the initial investment of Baltimore's industry in its well such laws and other measures as will promote the beneficial, supplies. efficient, and safe use. and conservation of the available water supplies. and help to develop any additional water supplies that A comparison of operating and maintenance costs for ground ..wa may be needed in different areas. ter and surface-water sources usually shows the same balance in favor of well supplies. Such a cost for one large industrial well sup To what extent these goals might be met by clarification or ~od ply in northern Delaware is somewhat less than 5 cents per 1000 ification of water rights is not specified by Ellis and Bausman smce gallons, which may be compared with an estimate of 3.08 cents per they suggest that: 1000 gallons reported for the total annual expense of Baltimore's ~dso~u industrial wells (Geyer, 1945). On the other hand complete oper ...... thorough study and discussion of various phases ation and maintenance costs for the Chester, Pa, surface-water tions of such problems are advisable before any new legJslatioD supply previously discussed were about 8.9 cents per 1000 gallons is adopted. Z17 in 1955 (Churi, 1956). 21b Such a study has now been made through the efforts of the Dela Upjohn Company uses well water so conservatively that some water ware State Chamber of Commerce New Castle County Water Re is reused four times, the last time for lawn watering (Water and sources Committee and the Delaware Water Resources Study Com Sewage Works, 1955). The School of Agriculture, Oregon State mittee. The latter group, as a supplement to their original findings, College, has estimated that the state can secure sufficient water to has submitted to the Governor a proposal for implementing a water double its existingirrigable acreage by reducinglosses at the farm policy for Delaware (1957). This proposal in essence suggests legis (Oregon Water Resources Committee, 1955). Still another form of lation to contj-ol the use of water for beneficial purposes through a conservation of immediate interest in Delaware would involve the water resources commission. use of brackish water for industrial and agricultural uses. The limitations on the use of such water are not clearly established, in Actual legislation encompassing such a commission has been the writer's opinion. submitted to the 119th General Assembly as Senate Bill No. 98. This proposed legislation follows along lines recommended by the There seems to be no real question about the need for a water Delaware Nater Resources Study Committee. Fundamentally, this commission in Delaware. Questions may rise, however, as to the legislation would modify Delaware's position under riparian law by extent of powers of such a commission, and the relation of the new introducing controls to provide for the beneficial use of the waters legislation to Delaware's present position under riparian law. of the state. The program would be administered by a new water resources commission. Control is to be maintained by .the new Unfortunately, the powers of sucha water-resources commission commission through a system of permits for the construction of can be severely restricted by the relatively simple arrangement of water-supply facilities. The basis for the issuance of such permits legislating exemptions from the law. Fortunately, Senate Bill 98 is the reasonable and beneficial use to be made of the water. There seems to carry a minimum of such exemptions although the writer is also implied but not spelled out, some of the reasoning of the new agrees with Murdoch that "all impoundments and all water diversions Oregon law, (Chapter 707, Section l(b), 1955). must be within the control of any new water use law" (Murdo ch, 1957). The exact power of such a commission over those riparian owners A proper utilization and control of the water resources of this not exempted under the bill may actually have to be determined in state can be achieved only through a coordinated, integrated the courts. Since riparian rights have been regarded in common state water resources policy, through plans and programs for law as property rights, there may be some question as to whether the development of such water resources, and through other these rights can be modified by legislation. The bill does exempt activities designed ttl encourage, promote, and secure the max those with vested rights, but by definition of the bill vested rights imum beneficial use and control of such water resources, all are determined by the lawful use which an owner has made of his carried out by a single state agency. water. Murdoch (1957) suggests that riparian rights may not nec essarily be dependent upon past use and this would run counter to Thus, in practice, the new commission would be guided in the the definition of Senate Bill 98. This same author, incidentally, does issuance of permits by an overall concept for the use of Delaware's conclude that the state may control non-riparian users, while vested water resources. A tremendous contribution would result from the riparian rights may be given constitutional protection by the state's preparation of an overall program for the management of the water use of eminent domain to take those riparian rights required for the resources of the state. public use. One interesting aspect of this proposed commission is its r eapon. The control over impounding and taking of water will, of course, sibility in interstate matters. Since national water-resources policy notresolve the problems of distribution discussed previously. How seems to be taking the direction of active interstate participation, it ever, the development of an overall water-resourceS management is fitting that Delaware should be preparing for its role in the use of plan by the proposed water commission may do much to clarify the major interstate water resources. relationship of the various aupphie r s and their obligations with re gard to the growing water needs of the state. Since the proposed This commission could also profitably encourage the wise use water commission would not have the authority of the agency sug of water obtained from any sour ceo This would certainly involve gested for New Jersey to "acquire, construct, and finance new wa conservation of usage. Specific examples of such conservation may ter supplies" (Tippett, Abbett, McCarthy and Strattan, Engineers, be found in the practices of public water utilities, industrial com 1945), their influence would have to be applied indirectly. How panies, and in agriculture. For example, the Artesian Water Com ever, the new legislation has not been conceived as a cure-all, and pany locally has suggested to its consumers methods for obtaining additional legislation may be required to correct those problem. areas a better lawn with less water (Artesian Water Company, 1956). The which cannot be resolved under Senate Bill 98. Such legislation could Z19 Z18 conceivably take the form of a Northern Delaware Water Authority is considered in general terms. The order of magnitude of invest with powers to develop an integrated water supply for the entire ment in upstream surface sources is seen to be about $700, 000 per northern Delaware area. This water authority could act as whole million gallons per day developed for many cities. The correspond saler to industry and private and public utilities. thus in effect pro ing investment in ground-water supplies is about one tenth of this. viding the presently desired linkage between various suppliers. The Means of financing any new supplies could include (1) private capital scope of the authority would be determined by the commission pro alone, (Z)private capital plus City of Wilmington, (3) joint contract posed under Senate Bill 98. by Wilmington and New Castle County, and (4) a northern Delaware Water Authority. SUMMARY A Northern Delaware Water Authority would only be needed if the currently proposed legislation to implement a water policy for The methods and problems associated with the formation of a Delaware proves incapable of resolving existing problems of dis plan of water management are presented in this section. The section tribution and supply. This proposed legislation, placed before the deals primarily with usage of water resources as regards water 119th General Assembly as Senate Bill 98, suggests a state-wide supply. Ultimately, all uses of water resources must be incorpor water commission w,ith powers to control the taking of water by a ated into an overall water-management plan. systemof permits. This is considered by the sponsors as modifying Delaware's present position under riparian law by the reasonable The first requirement is the projection of the water supply needs use principle. hnplied in the operation of this commission is the of nort hern Delaware. Engineers for the Levy Court have projected development of an overall water-resources management plan for the average annual requirements for the area of 80 million gallons Delaware, while the commission is specifically designated ail the per day. A land use analysis of the area is suggested to focus more cooperating agency in interstate water compacts. Another func~ clearly the influence of future industrial development upon this esti not specifically de ai gnated in Senate Bill 98 might properly be to mate. promote conservation of water usage generally within the state.' ,-. The development of ground and surface water-sources to meet This commission would not have powers to finance andcoDstruct this need are discussed in terms of the procedures by which the water-supply facilities. However, under the state-wide water-re· yields of such supplies are obtained. The only comprehensive plan sources management plan developed by the commission the pre~e' offered to date, that by the Levy Court Engineers, found an ample needs of the area should be defined. In the event that there is DO supply for the projected demand of 80 Tillion gallons per day. The prospect of meeting these needs by other means, the above men" exact means of developing surface storage are not specified except tioned Northern Delaware Water Authority could be established bY' . that joint use of Hoopes Reservoir for the Wilmington Municipal legislation. This authority would have its scope defined by ,the com .. ' Supply and the General Water Works Corporation is suggested. The mission. Presumably it could act as wholesaler of water to pri vate provisions of the study limited the study insofar as financial and and municipal utilities and to industry, having the power and finaDOi organizational matters are concerned. The development of a sound ing available to achieve this purpose. plan of water-resources management r equd r e s a full scale analysis of all available streams including major rivers such as the Susque hanna and Delaware and must of necessity incorporate legal and economic aspects. The plan should consider northern Delaware as the center of an industrial belt extending from New York to Baltimore. The technological aspects of the treatment and distribution of any developed water supply are straightforward. The area has a unique situtation as regards arranging for distribution of water since some 14 companies serve water consumers in northern Delaware. Voluntary integration of the main suppliers has been suggested by some groups, but the reported Wilmington policy does not place such a plan in a favorable light. Failing such a voluntary move some type of legislation may be required. The financial and legal aspects of water-resources development ZZO REFERENCES REFERENCES- - Continued. Oregon Water Resources Committee, 1955, Rept, of Water Re Albright and Friel, Inc, , 1945, Report to ChesterMunicipal Author sources Committee submitted to 48th Legislative Assembly, ity on new water supply, Philadelphia, Pa. State of Oregon, Portland, Oregon. American Society of Civil Engineers, 1948, Hydrology, handbook Powell, S. T., 1948, Some aspects for the quality of water for in manual of practice no. 28, New York, N. Y. dustrial users, Sewage Works Journal, .v , 20, p.36. Artesian Water Company, 1956, Bulletin 13, Newport, Delaware. Shehadi, F. et al., 1951, Industrial water supply for the SouthBalti more Area, - Graduate seminar rept.: Dept. of Sanitary Engi Churi, M., 1956, Personal communication dated Mar. 26, Ches neering and Water Resources, Johns Hopkins Univ. ,Baltimore, ter, Pa. Md. Delaware Engineering Association, 1954, Planning f CJ[' the future Tippetts, Abbett, McCarthy, and Stratton, Engineers, 1955, Survey water supply of New Castle County. of New Jersey water resources development, New York, N. Y. Delaware Water Pollution Commission, 1955, Sixth Annual Rept. , Water and Sewage Works, 1955, v , 102, p, 426. Dover, Delaware. Whitman, Requardt, and Associates, 1956, R~porttothe LevyCourt Delaware Water Resources Study Committee, 1955, Water in Dela of New Castle County on water supplies in New Castle County, ware, a preliminary rept. Baltimore, Maryland. Delaware Water Resources Study Committee, 1957, A proposal for Wills, W. C., 1931, The old mill-stream project, .Wilmington, Del implementing a water policy for Delaware. aware: Jour. Am. Water Works Association, v , 23, p, 561. Ellis, H. H. , and Bausman, R. 0., 1955, Some legal aspects of water Wills. W.C .• 1948, Suburban extensions: Jour. Am. Water Works use in Delaware: Univ. of Delaware Agric. Exper. Sta. Bull. 314 Association, v.40, p. 1246. (Tech. ). Wilmington Street and Sewer Department, 1955, Sewage treatment Engineering News Record, 1956, v , 158, no. 8. program: Wilmington, Delaware. Geyer, J. C., 1945, Ground water in the Baltimore industrial area: Maryland State Planning Cornrn,, , Annapolis, Maryland. Friel, F. S., 1951, Chester, Pa., develops a new water supply source: Water Works Eng., January. Lohr, E. W., and others, 1953, The industrial utility of public water supplies in the South Atlantic States: U. S. Geological Survey Circular 269. Louisiana Legislative Council, 1955, Research Report 5, Baton Rouge, Louisiana. Murdoch, J. H., Jr., 1957, Some thoughts on proposals for new wa ter use laws for EasternStates: Water and Sewage Works, v.l04, no. 3. zzz 223 .~. ERRATA p. 34, last paragraph: for p, 127 read p. 128 p. 50, third paragraph: for p, 138 read p, 140 p. 66, second paragraph: for p, 172 readp. 173 p. 67, third paragraph: for p, 152 read p, 154 p. 138, third paragraph: for p. 144 read p, 146 p. 154, last paragraph: for p. 158 read p. 160 for p. 163 read p, 164 p. 156, first sentence: for p, 166 read p. 167 for p. 167 read p, 168 p. 178, third paragraph: for p, 113 read p, 114 p. 188, third paragraph: for p, 195 read p, 196 for p, 171 r.ead p, 172 p. 188, fourth paragraph: for p, 144 read p, 148 Table 8.--Storage-reguired £regu"""y at stream-gaging stations in northern Delaware. (Adjusted to 57-year period, 1896-1952, on baais of long-term streamflow records in adjacent states). Allowable draft (mgd per sq mi) for the amount of storage, uncorrected Gagi"l! station Drainage Recurrence Natural for reservoir seepage and evaporation, indicated in colUDl beadi"l!s area interval 7-day sq mi years flow 0.5 1.0 2 3 5 10 15 20 30 50 lI!!jclsm gI- gI- glam gI- glam gI- gI- gI- gI- glam Sbe11pot Creek 7.46 2 0.065 0.104 0.122 0.146 0.163 0.193 0.239 0.279 0.311 0.374 0.484 at 5 .039 .067 .080 .096 .107 .128 .169 .203 .234 .288 .388 Wil.m!.naton 10 .030 .056 .066 .079 .089 .106 .140 .170 .196 .246 .336 25 .023 .045 .053 .063 .072 .086 .116 .142 .165 .210 .289 Brandywine Creek 314 2 0.266 0.310 0.348 0.389 0.418 0.461 0.533 0.583 0.625 0.702 0.830 at 5 .194 .244 .264 .289 .309 .346 .402 .444 .485 .552 .671 Wl1mi1Jl!ton 10 .167 .210 .229 .252 .270 .299 .350 .389 .423 .482 .586 25 .139 .175 .195 .218 .235 .256 .294 .329 .361 .419 .524 R.ed Clay Creek 47.0 2 0.254 0.312 0.346 0.398 0.436 0.500 0.562 0.616 0.662 0.742 0.872 at 5 .179 .229 .258 .296 .323 .360 .425 .464 .506 .568 .683 WoocIda1e 10 .150 .197 .222 .253 .275 .307 .363 .402 .440 .496 .594 25 .129 .167 .189 .214 .232 .256 .296 .331 .360 .415 .511 White Clay Creek 87.8 2 0.236 0.289 0.321 0.370 0.410 0.443 0.514 0.571 0.619 0.700 0.825 near 5 .166 .217 .245 .278 .303 .339 .398 .453 .484 .547 .652 Newark 10 .140 .183 .206 .239 .260 .293 .342 .383 .409 .472 .576 25 .121 .154 .177 .204 .219 .243 .283 .315 .344 .397 .495 Christina River 20.5 2 0.124 0.177 0.204 0.246 0.276 0.320 0.381 0.429 0.472 0.545 Q.670 at 5 .076 .121 .139 .166 .187 .221 .267 .308 .342 .404 .511 Coocbs Bridge 10 .060 .098 .115 .133 .153 .178 .220 .256 .288 .344 .441 25 .048 .080 .094 .110 .122 .138 .172 .204 .232 .282 .368 Note: Figures for White Clay Creek above Newark are identical with White Clay Creek near Newark. 7-day minimum flow considered as flow with zero storage. :-t CO f~ I Plate 1. --Photograph of a typical gaging station on Red Clay Creek at Wooddale, Del. f..e 3 / A I • / / I / I ~XPLANATION I 0 2 i ...... -§iii! ...... Sca le in miles L ines of cross sections A-B Great Circle to Iron Hi ll , f igure 36 C-D Newark to Delaware City, plate 3 E-F along Cona l, plate 6 SEDIMENTARY ROCKS Pleistocene deposits which mantle the > Coastal Plain have been omitted cr Bryn Mawr (?) grovel (Red, indurat ed, gravelly sdnd and si It, f orming terrace depos its on gabbro plateau above alt itude of 300 feet) I / ~~ r.b:.~ { Red Bonk sand e (Glauconitic sand) . >I \ I J ~ OJ ttili.nm o " Navesink marl and Mount Laurel sand undifferentiated ..u )' o (Glauconitic sand , silt, and cloy) ~ (f) U m k :~\;. l => .. Wenonah sand o 0. 0. (Glauconitic sand) w :::l U <1 [~ I w Merchantville cloy cr ( Glauconitic sand and slit) u ~[nj~ .. Magothy formation " (Lignitic sand and gray cloy) "O~C U 0,2 { .. .. r{Pf':'<.. :...0j .~u Patu xent, Patapsco and o -l .. Raritan formations, undifferentiated 0. (Buff sand and vari egated cloy) 0. :::l IGNEOUS AND METAMORPHIC ROCKS --...... ('.. ~ F:"" ~ U Pegmatite dikes Granodiorite 0 N 0 l ~ g J ~ ~ . W }...J Gabb ro Serpent ine a. E Plate 3. __Ge neralized leo~ ic map of no rthern Delaware. ~,S N <:; ~/..j 18 I ------~~~._ ------_../ M~ I I I I I i ,1 \ I 1 ~ . \ D\ -----~ / / : / / V / \ // /l ( / '/; / VI I \ / EXPLANATION CHESAPEAKE '---100 -- Contours on the top of the crystalline 13 basement rock (base of the sedimentary I I rocks). Altitudes in feet above or below mean sea level. \ I I • -126 Well showing altitude of basement. \ I Scale in miles I I 1/2 0 I 2 _! I I \ - I I I N TE RP RE T AT ION SA MPLE W. C, Ras muss e n , USGS T IVITY S ys t em DR ILL E R' S L OG DESC RIPTION ELEC TR I CAL L OG RAD IOAC LO G C OM POSIT E LO G or J . H. Rulon W. C. Rasmusse n, USGS S o hl um be rge r Well Surveying Corp. Thi ck nes s Wat e r po ss ibil it ies Format ion S e rie s 8 ' fe et o above -, - - Sa nd ------S and, medium, brown : Pre s ent us e sea level - -- - - Sand " grove l ------Sond, ooor se to fine , brown,w oter '. 600,0 00 9 pd 2 0 - : : ," - -Vellow sa nd" llrove l ------Sond,c oorse 10 fine, yellow'br own, with Silt }"'Sd Q Q Q ;, Whit- sand R. 0rnv_1------Grovel fine ar it 3 0 a .; 0 30 Vellow sa nd" cloy Sond,med ium fa very fine,8 s ilt, fer rug inous,bro. n 33 }7' Clay -- Gray cloy------Clov. t ouah blue ' 9"ra'-'y'-- -I 40 40 ------Red Cloy ------Cloy, tough, red - brown ------Silt Tes t e d ; poor - - Red a ",hi le clov ------Clay, tough ,v ari eQOted red brown to light gray ------}2' _- White sandy clay------Sill,sa ndy,y'eliow, red a gra y 5 2 } 9' Clay Vellow eondv clov Silt sondv. or anae '. .-: : 61 .::::- Sa ndy Clay , hard - Sa nd, very fine, ye llow Sand, ~~u!..trp,-,Ie"cc- Po or ' Sa nd etone ------Iron s tone s ondv _ 70 . -: - .-.- " 18' Very fine l'-'. - } f- -- Vellow eondy cloy, fine - -- -- Sond,me dium fiIIe , a sil t clay ~.~~ =-~ -- : s ilt y aond Grove l 80 79 . - White eondy cloy ------Silt, sandy, -liver- gra y a 87 -- Vellow cloy - ha rd ------Clay, tou gh , gr a y ·...it h yel low st re a ks 90 s an dy 90 100'- 1--98 - - Whi,. cloy------ Cloy, non-p la s t ic , white 98 Cloy, ploslic, mauve . clay ~'!.:'WJ'!!.e_~~y_red,oroy !::;=-07-lln lt =_R~ ~ ~ clay I ClOY.PiostiC:aroy - cloy, plosllC, groy - bro.. n }~CI" ~1iO - - 6 ro. oIov------1 10 us --- Dark gray cloy ------ Cloy, pla st ic, co rbona ceou., Qroy - blook I 8_ ~ 1I Vell ow sand orovl l ------ Sand coorse 10 mediu m " rit . vella,", a b row n ' -12 0 ~ Upper aquifer 1'2122,':: :. - - White sand grove l ------ Gravel, fine ,gri t a coo r. e ond,ono ulor groy-b"" n ~>~ ~~:,oo 27. ~ 1 _ - Vellow San d orave l 4" sandst one - - :: La rge ca paci t y Grit S sand oo a rs e Ironsto ne waf ers 13 0 _ } 23'Sand a ~ i33' ., e , " .- }. gr ave l we ll deve lo pe d L...... 13 8 f- - -Gr ay eond y cloy ------Cloy, silt y, gray ~ '- , -, c-, ---- I 14 0 - I-- - Red oray oloy ------ Cloy, gummy, chocolote- brown I 11484 2 j 12' Clay ? ~ _:;_:-::-:-~ _::_::_::_:_:= -::-:--,+------i r------~===!::l-- -l:----:--I 50'-~1481==_= ;:;,_;;_:_:_,..._::_~~ :_::_------+-;;;-...:..:._7.::~ _':.::::__:_:_; 1 ~ Clay 50 ~ !54 - Vellow eond clay ------Cloy, oilty, voriegoled red,groy, oronge, :tellow ~ . ' .' ' '; 154 5' Sa nd white nd - - - - i '" . 156'=f-- -- Fine ea -- --- Sand fi ne .ell s orled orov ' 16 0 .- ." 15 9 It' I 16 4 '" Ca y I- -- Fine . ondy cloy -hurd ------Sand, fine to very fine , Clayey, yellow ~ . ' . - 17 0 - . . Te s t in fut ure S~,;.j::. _ . 1-- 17 0 .: ~ . -- Red eroy cloyaeand e' reaks - -- - Cloy, eilty, voriegoled purple , red, gray 120' Sand 180 - ~ ~ G= Not very p ro mising ~1801- . Fine S'ond cloy slre oks, chorcoo l - - - Cloy, silty , red, yellow,oray,otreoks of charcoal I 184 J 87~ ~ J;>'_ 1 - Red arov clov ------Cia• . touoh Dlost ic varieaat ed vellow, arav. brawn -19 0 92 ~ 1 -- Red white cloy ------ Clay, plastio , re ddish ora y SPONTANEOUS - POT EN TI AL 200" -- Red a rov cloy ------Clay , -red brown .. yellowish gray RE SISTI VITY 1-- 2 0 5 - Cia. etreake white s and ------Muc k, oray -bloc k ------+_1 0+-- -=~= ==-==~ = "-----+ -7-"= L.!=!-= = :.,_,___, 1- 2 1 : Cloy 21 0 ~ 215 - - Blue clay ------Clay , t ouOh, or ay' black - - Re d ora v cia. ------Clav. sand v. touah orav -br_n I - 2 20+- -~ ...... ,,;L-" '-"L------_t --= =..1--= = u....:=c:L -"-'-':L. = = ------_i .. 2 2 0 ' Clay - 2 25 - Red o ra y cloy ------Clay, red ' br o wn eo I 230 - - Brown c loy, tauOh ------Cloy , gri tty, re d - BrO\lln cia v efreoks or o. ------Clav. t ouc h rod a gray ~ <='---- _+_-'<'-'!L.L.-'-''''''''-'--'-''-''-''''-''-'-''!L...------_i - 2 37 '=-==>'-='=---"-'-""'--''-''-''-''-'' 240 - 24 2 J cl oy -- Brown cloy - - - - Clay, so ft, red Schlumbe rger 24 8 ------250 "- - l:::----,::- --- -,------+--::,.,.----,-.,-;:----;cc-;-:,...-;:----,----,------t- -- Interpret a tion - 255 Brown oro y cloy ------Clay, soft , IiOht brown Clav Dlos l ic , red - brown , pe bbl.. - Brown gray cloy - - - - - .,...- 264 ".' . - .. : -; -- Brown cloy Itrea ks whit e .on d - - - , .:... ". ". . Unsu c cess fu l t es t '. " San d 280 - }20' Ve ry lit t le wat e r 284 ) 4 'Cloy - 2 8 8 290 .- ':: ..: ', ' } 7' Sa nd - Coore e oroy s and , 9ray c lay - - - - Sa nd, medium to coorse , sa lt a pep per , : 29 5 layer. of whIte oilty cla y } 9 ' Cloy , ,.. 304 -- 3 ' San d 310 307 -- Red cloy ------Cloy , Soft, ll'lostic, re d a } 8 ' Clay 3 20 .' .- 319 4' Sand 32 3 Middle aquife 3 2 7 4 ' Cloy r? 330 - .- cloy '. Tes t in f ut ure ~ ~ Sand, 1Ine, eilty, ahoco lote Sand -- Sand a clo. ------ I ~S d ' }3' --'-340 f--'''''-''''-''''-'= - - - - - + ....-o,.,...-,= =-...:-=-::-:-=--:o::-::-:co:-::-::;------: 34 0 340 White red '----oloy------ Silt, .li te a bro wn, st, oa ked ~ 4' Cla y ? 1---345 -- , 34 4 - - White aond-cl av- ond medium to fine s ilt gray ..Sond :. -, : }6' Sa nd --== ::>....-- j= ;:__- t_- - +-- - 'f'_'_'-,-+-'-'-'-- -+:,;<6;;-<'F-- -+-- -r~~ t_------~~~c..::=-======:.=.- +--=~==~~ ~~ '-"-'-~---- _:.+-- -+-~+ 350!..f--350+-~!!..!.!..!.!.J!.....------350 350 -- 8rown Clov - hord- - _ _ Cloy Clay C:a y Clay, plasl ic:,Orit ly, re d }20' 1-- 37 ------+ ------1i ~ sec 0+--- ~ 370 : 370 " Sa nd : " -, Te s t in fu tu r e wat or : ' ~ : .. } IO' S a nd - 38 0 380 -- Clay - hard - - - - - Clay . ha rd , var iegat ed red. bro. " ------a oro. 1 3 90 }23' Cloy 1 4 0 3 -- Brown sand ------Sand, medium, dirty, br own .' 40 6 3 'S a nd I I a 41 0 . . I ' .. , ollndy .'. I Cloy 4 20 -- Fine br own s and, .ilt , c loy-- --- Sand, f ine , s ilt a cla y, tlro" n cloy I Q 430 68 ' Cloy 1-;-;-4 4 0 +------+ ------+I_1 s andy 44 0 ...... -- Cla yey eond ------ Sand, me dium, cla ysy, brown I 450!... ,.:.....:..450f------t_ ------i --/- - + -l>;- t-- ---f cloy -- Cla yey oond cloy ------Sand fino 10 med ium, cloy..y, brown -- {-1 46 0 r-- ,n o+ ------I------1~ 470 j Lowe r aq uifer? -- SandY clav ------Clav s andy. brown : 474 480 - : Te st in f ut ure S and. silty J ."- }7' 49 0 - 4 9 1 -- Sa nd .. clo y ------Sand, coa rse , c layey , brown I ~ - - - - -~ "--+-- - 500 !lOO' e-- 500t-___,;-;-:-: ------j-,;;---, ,..--;-:--,--::---::;-- -l t-----cI---7?t--- -j r------1 - - - e-505 f- - Clay---,------Sand , f ine , in brown Cloy ------}23:Weathered l one, cla y Grov eond - - Sa nd coa rse angular clayey ,- IliI ------5 10 - - 5 14 I~ - - - -::::::-==- ..,g 514 - - Roc k------.- - - - Rock, oryslo lline , hard 515 T P I Rock P la t e 6. - -Comp osi te log of a d e e p te e t. hole a t Ne w C e.s tl .e, De l , ,..------1 '------;f------, FQ. 7 N 70 coO 40 N .30 ./0 o EXPLANATION Over-h.,CKJI" C~b/e Novigation lights o Observation ...12 well \----:,...-~ Quaternary I o LORrvoOD p eistocene seoes Eb 31-1 system IV ..seer/on /;, nor-II> 038 bonk o,eo CO/7.,/ [.:.'t/!i/ :] Red Bonk sand I Navesink marl and .s Seer /on ,n .so",lh £a44- ~3 Mount Laurel sand, bonk 01' Canol o undifferentiated €JCfr-apolafed 1-0 Ea 44-3 I~·.'·:.:.j norll> coni- assurn;ng QCALE .. ..- Wenonah sand a 0,," . Cretaceous _ srr /ke 45° I, . system ~--=-~Merchantville clay NL Secf/on /n nor-II> -- .bonk 01' COrJC:Il oblo /ned f'rorn pre .soo, I v/ou.s //ferolurq j : i i ~ Magolhy formation /000 0 .5000 ./0,000 as /nlerprel-ed iJy pre$en r IoVr/rer.5. Rarilon formation - I Plate 7. --Geolog ic cross s ect ion of the outcrop of Creta Jeous rocks and Pleistocene depos its along the Che sapeakeI and Delaware Canal. I. l 75°45' 75°40' 75°35' 75°30 75°25' a b c d e A ------ B o ( . o / I 39°45' / / N 39°45' / / / / / I I P~~~I-,-- . c I I I I I I I I 39°40' 39°4d o EXPLANATION Contours on the base of the Pleistocene series, interval 40 feet, datum sea level. ----+80------+4 0 ------0 ------x- x--40 - '-x- 39° 35' - ----80 ---- 39°35' ---. - - -120------ Points of control • Well Electrical-resistivity station ® High-level valley partially confined by +40 contours, +- arrows indicate conjectured trend. Altitude of bottom ranges from+20 in north to -5 near canal. Medium-level vall ey, confined between-40 contours, E grade ranges from - S2 to -S7, north to south. Low-level volley, confined between - SO contours. Latest volley, confined between - SO and-120 contours . Scale in feet 10,000 5,000 o 5,000 10,000 1 - - I'""" ...,- 1'"""-"" . 39°30' . 75°45' ~ 75°40' 75°35' 75°30' 75°25' Plate 8} --Configuration of the base of the Pleistocene series in northern g el a w a r e o