HydrocnemicalT T 1 1 * 1 FaciesT^ * and1 Ground-Water Flow
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E O L O G I C A L S LU R V E Y PR OF E S S I O N A L PA PER 4 ® B - A Hydrochemical Fades and Ground-Water Flow Patterns in Northern Part of Atlantic Coastal Plain
By WILLIAM BACK
HYDROLOGY OF AQUIFER SYSTEMS
GEOLOGICAL SURVEY PROFESSIONAL PAPER 498-A
UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 DEPARTMENT OF THE INTERIOR
DONALD PAUL HODEL, Secretary
U.S. GEOLOGICAL SURVEY
Dallas L. Peck, Director
Any use of trade names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey
First printing 1966 Second printing 1988
For sale by the Books and Open-File Reports Section, U.S. Geological Survey Federal Center, Box 25425, Denver, CO 80225 CONTENTS
Page Page Abstract. ______Al Hydrochemical facies Continued Introduction-_____-_--_----______1 Occurrence of hydrochemical facies Continued Geology--_--____.______....______.____.___ 2 Cretaceous sediments..______A15 Relation of salt water to fresh water.______2 Eocene formations.______-----_ 22 Factors affecting position of the salt-water body.--. 2 Miocene formations.__--_----__-----_------31 Factors affecting occurrence of salt water.______9 Spatial distribution and origin of hydrochemical Ground-water flow patterns.______9 facies______-___---_-_-__------__ 37 Hydrochemical facies..._---__--_--___-_-______-_____ 11 Concentration of dissolved solids______37 Definition... ______11 Cation facies.______-_____--__-_--___ 38 Procedures and mapping techniques.-______--_-___ 14 Anion facies______39 Occurrence of hydrochemical facies within strati- Summary and conclusions..______40 graphic units.-_----_-______.__ 15 Selected references.______-___-__------__ 41
ILLUSTRATIONS
PLATE 1. Fence diagrams of the northern part of Atlantic Coastal Plain. ______-______---_----_ In pocket FIGURE 1. Index map of part of the northern Atlantic Coastal Plain showing location of cross sections in the fence dia grams. _ -__.-___.___._.___.___..____._...... ____.__.__._____-._._._--__.-___-.-----.------. A3 2. Map showing the relation of topography to salt- and fresh-water interfaces.______.______------___ 7 3. Map showing general pattern of ground-water flow in the Cretaceous sediments______10 4. Sections showing the vertical component of the major ground-water flow.______12 5-18. Water-analysis diagrams: 5. Hydrochemical facies, in percent of total equivalents per million______14 6. Cretaceous formations in Virginia______16 7. Mattaponi Formation in Virginia______-__---__-_-_---_------__-_- 18 8. Cretaceous formations in Maryland.______20 9. Magothy and Raritan Formations in New Jersey------.------22 10. Selected Cretaceous formations in New Jersey. _-______-_-__--__-_-___-_---______------24 11. Englishtown and Vincentown Formations in New Jersey. ______-_--_---_-___------_---- 26 12. Eocene formations in Virginia.______28 13. Aquia Greensand in Maryland.______29 14. Selected Eocene formations in Maryland..______30 15. Miocene formations in Virginia. ______32 16. Miocene formations in Maryland...______-_-_.-______33 17. Kirkwood Formation in New Jersey.______34 18. Cohansey Sand in New Jersey___-___--____-_.__._.______----__-_--____---_--_-___ 36 in IV CONTENTS TABLES
TABLE 1. Stratigraphic units of the northern part of the Coastal Plain. ______A 4 2. Classification of hydrochemical facies.______--___-____-----_-___--____ 13 3-15. Analyses of water from 3. Undifferentiated Cretaceous formations in Virginia. ______17 4. Mattaponi Formation in Virginia...__.______.______.__---___-_____-_--_--_-_---__-_------19 5. Cretaceous formations in Maryland______-______--______------__-_------21 6. Magothy and Raritan Formations in New Jersey.______-______--___-_-__------23 7. Selected Cretaceous formations in New Jersey. ______-______--_-______------__---.--- 23 8. Englishtown and Vincentown Formations in New Jersey. ______25 9. Eocene formations in Virginia..______--_-____-_-______----_-___-----_-_-_-----_ 25 10. Aquia Greensand in Maryland.______27 11. Selected Eocene formations in Maryland__._.____.______.____--______--____-____-_-__-__---_-_ 27 12. Miocene formations in Virginia______--_-______--____--_-.--___---____ 31 13. Miocene formations in Maryland.______35 14. Kirkwood Formation in New Jersey______-______-__--_-----_---_------35 15. Cohansey Sand in New Jersey. ______-______-__--__--__.-----__--_-__-_- 37 HYDROLOGY OF AQUIFER SYSTEMS
HYDROCHEMICAL FACIES AND GROUND-WATER FLOW PATTERNS IN NORTHERN PART OF ATLANTIC COASTAL PLAIN
By WILLIAM BACK
ABSTRACT INTRODUCTION The part of the Atlantic Coastal Plain that extends from New Jersey through Virginia was selected as a suitable field The science of chemical geohydrology in the United model in which to study the relationships between geology, States has for many years received little attention, not hydrology, and chemical character of ground water. The only in comparison with the general field of ground- ground-water flow pattern is the principal hydrologic control water hydrology, but also in comparison with the broad on the chemical character of the water. Within the Coastal field of geochemistry. Of the geochemical cycle of the Plain sediments, the proportions of clay, glauconitic sand, and elements the part that has been studied least is that in calcareous material are the principal lithologic controls over the chemistry of the water. which the circulation of ground water modifies the con A subsurface body of salt water extends from southern New centration and distribution of chemical constituents Jersey through southern Virginia and occupies the deposits within particular environments of the earth's crust. deeper than about 500 feet below land surface in the eastern Most of the interpretative reports prepared in this part of the Coastal Plain. The position of its top is determined country that pertain to the hydrosphere has been re by the relative head, which in turn is influenced by topography, drainage density, and the thickness and permeability of the stricted to the fields of oceanography, potamology, and Coastal Plain sediments. limnology. Hydrochemical facies is a term used in this paper to denote Although the amount of water stored in and circu the diagnostic chemical aspect of ground-water solutions oc lating through the rocks is but a small percentage of the curring in hydrologic systems. The facies reflect the response total water of the earth, it is this water that is largely of chemical processes operating within the lithologic framework and also the pattern of flow of the water. The distribution responsible for both the chemical character and quantity of these facies is shown in trilinear diagrams and isometric of dissolved solids carried to the oceans by streams. fence diagrams and on maps showing isopleths of chemical con This paper and certain succeeding papers in this series stituents within certain formations. The occurrence of the var are concerned with this part of the geochemical cycle. ious facies within one formation or within a group of forma Interest in the geochemistry of ground water has tions of uniform mineralogy indicates that the ground-water been gradually increasing during the past several years. flow through the aquifer system modifies the distribution of the facies. One factor that has contributed to this renewed and in Flow patterns of fresh ground water shown on maps and in creased interest is the realization of the significance of cross sections have been deduced from available water-level ground-water circulation in the occurrence of uranium data. These patterns are controlled by the distribution of the minerals in the Colorado Plateau. Another significant higher landmasses and by the depth to either bedrock or to the factor has been the realization that hydrochemical salt-water interface. The mapping of hydrochemical facies features of a basin may reflect the hydrodynamics of shows that at shallow depths within the Coastal Plain (less than about 200 ft) the calcium-magnesium cation facies gener petroleum accumulation. ally predominates. The bicarbonate anion facies occurs within The primary purpose of the study reported here is to more of the shallow Coastal Plain sediments than does the sul- relate the chemical character of ground water to the fate or the chloride facies. In deeper formations, the sodium geologic and hydrologic environment. The identifica chloride character predominates. The lower dissolved-solids tion and emphasis of these interrelations should pro content of the ground water in New Jersey indicates less up vide a firm basis for future study, which will be useful ward vertical leakage than in Maryland and Virginia, where the shallow formations contain solutions of higher in improving data-collection programs and enabling concentration. more effective utilization of our water supplies. This Al A2 HYDROLOGY OF AQUIFER SYSTEMS report is largely a description and presentation of the I am grateful to E. G. Otton, P. M. Brown, Alien chemistry of ground water in the Coastal Plain por Sinnott, H. C. Barksdale, and W. C. Rasmussen for tions of Virginia, Maryland, Delaware, and New Jer making these data available and particularly to R. R. sey. The Atlantic Coastal Plain was selected for study Bennett for his many helpful discussions. because of its diverse geology and the large amount of GEOLOGY information available from previous ground-water investigations. The geology and hydrology are known The Coastal Plain is underlain by a wedge of sedi in broad general terms but not in detail, whereas the ments ranging in age from Cretaceous to Recent and chemistry of the water is known in detail for some areas consisting primarily of sand, silt, and clay, with minor but its regional setting is not well understood. The amounts of gravel overlying the pre-Cretaceous bed major stratigraphic units and their gross lithology are rock. Several studies of the geology of Coastal Plain known, but detailed knowledge of their mineralogy is were used in the preparation of this paper for informa usually lacking. Generalized piezometric maps are tion on stratigraphic correlation and lithologic available for some areas, but the movement of ground character of sediments. Although the stratigraphic re water in many areas is only poorly understood. lationships are fairly well understood, little detailed information is available on the mineralogy of the In any area the main factors that control the chemical Coastal Plain sediments. The major stratigraphic character of ground water are the climate and vegeta units are summarized in table 1 from the extensive lit tive cover, the mineral composition and physical prop erature of the geology of the Coastal Plain (among erties of the rocks and soil through which the water circulates, and the relief of the land surface. Humid which are Anderson and others, 1948; Bennett and climate (precipitation about 45 in. per yr) is character Meyer, 1952; Cederstrom 1943b; Groot, 1955; Johnson istic throughout this part of the Coastal Plain and is and Richards, 1952; Owens and Minard, 1960; not discussed in this paper. Other factors that affect Richards, 1945, 1948; Spangler and Peterson, 1950). the chemistry of the water are physical and chemical The lithologic properties that most greatly affect the character of the soils through which the water perco chemistry of the water are shown on plate 1A. The lates and the activity of microorganisms. sediments are divided into those deposits predominantly The controls on the chemistry of the water considered of continental origin and those deposits predominantly in this paper are the physical properties and mineral- of marine origin. A fourfold subdivision of these two ogic composition of the sediments and the movement of major units is made on the basis of the percentage of ground water. The biochemical effect of microorgan clay within each sequence. The units are further diff isms is not sufficiently understood to be considered in erentiated as to the presence of greensand (glauconitic this type of study. The influence of the soils on the sand) or calcareous material. The percentage of clay chemistry of the water is also beyond the scope of the and the presence or absence of greensand and calcareous present study. sediments are believed to be the dominant controls on The area of the Coastal Plain reported herein ex the chemistry of the water. Although the percentages tends from southern Virginia northward through New of clay as shown in this illustration are approximate, Jersey as shown in figure 1. It is approximately 300 the general relationships and the relative amounts of miles long and ranges in width from about 30 to 110 clay, greensand, and calcareous sediments are represent miles. ative of the regional variations. More than 3,000 chemical analyses were studied dur ing this investigation; however, only about 200 are RELATION OF SALT WATER TO FRESH WATER shown on the fence diagrams. Among the analyses FACTORS AFFECTING POSITION OF THE SALT-WATER generally not used were partial analyses and analyses BODY in which sodium and potassium were determined by Figure 2 shows the generalized topography of the difference. Where replicate analyses were available, Coastal Plain. The highest parts of the Coastal Plain the most nearly representative analysis is shown on the are near the Fall Zone. However, two landmasses not fence diagram. Where the location of the source of the connected with the Fall Zone are in southern Maryland sample was unknown, the analysis could not be used. and in northern New Jersey, where the altitude is about The data used for this study were obtained from pub 300 feet. As can be seen in figure 2 the altitude of most lished reports of the U.S. Geological Survey in cooper of the eastern part of the Coastal Plain, including the ation with State water agencies, and from the Eastern Shore of Maryland and most of Delaware, is unpublished-data files in the district offices in each State. less than 100 feet and is generally less than 50 feet. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A3
78° 77° 76° 75°
DGE OF COASTAL PLAIN SEDIMENTS
____ _
FK:UUE 1. Part of the northern Atlantic Coastal Plain : location of cross sections in the fence diagrams. A4 HYDROLOGY OF AQUIFER SYSTEMS
TABLE 1. Stratigraphic units of the northern part of the Coastal Plain
Virginia Southern Maryland Delmar Peninsula New Jersey
Alluvium, Qal, sand and gravel, chiefly beach deposits (of wind and wave origin) and channel deposits (of fluvial origin) and smaller amounts of marsh and lagoon deposits, dunes, bay-mount bars and spits. Columbia group, Qdu, 0-60 ft, clay and Lowland deposits, Qdu, 0-150ft,sand, Columbia Group, Qdu, 0-150 ft, unconsol- Cape May Formation, Qcm, 0-200 ft, buff to sand; fluvial and marine; the higher, gravel, sandy clay, and clay; fluvial idated lenticular deposits of buff sand brown poorly to well-sorted unconsoMated westerly terraces are of continental ori and marine. and silt, and small amounts of gravel and gravel, sand, silt, and clay in filled valleys gin; the lower, easterly terraces are of clay; fluvial and marine; deposits occur and broad alluvial terraces; fluvial and marine origin. as stratified drift containing a few er marine (Pleistocene). ratic boulders, stabilized dunes, marsh mud, crossbedded channel fill, well- sorted beach sand. Disconformable lower boundary.
Upland deposits, 0-55 ft, irregularly Brandywine, Bryn Mawr, and Beacon Beacon Hill and Bryn Mawr Gravels, 0-20 ft, stratified cobbles, gravel, sand, and Hill Gravels, 0-70 ft, slightly cemented iron-stained gravel and sand composed of clay lenses; fluvial and marine (Pli red, orange, and brown gravelly sand. residually weathered quartz, chert, and ocene and Pleistocene). Locally in hard ledges a few inches to 2 ft quartzite; caps a few hills as remmants of a thick, usually at the base of the forma once extensive alluvial plain. Semiconsol- tion. Chiefly channel fill. Disconform idated permeable deposits chiefly above the able lower boundary (Pliocene and water table. Transmits water to under Pleistocene). lying aquifers (Pliocene and Pleistocene).
Yorktown Formation, Ty, sandy Yorktown Formation Ty, and Cohansey Cohansey Sand, Teh, 0-270 ft, coarse to fine and very fossiliferous. Sand, Teh, 0-150 ft, gray sand and gray quartz sand and lenses of silt and clay; or blue clayey silt; the sands are predom estuarine and de Itaic; possibly marine down- inantly fine to medium grained; coarse dip toward the ocean; loosely consolidated sand, grit, or fine gravel present in minor thick permeable aquifer. Chiefly uncon- amounts. Black sand, green sand, and fined; receives direct recharge. Locally shell beds are reported locally. The artesian (Miocene? and Pliocene?). clayey silt is occasionally brown or green. Estuarine and marine. Disconformable lowfer boundary.
St. Marys Formation,Tsm, con St. Marys Formation, Tsm, 0-50 ft, St. Marys Formation, Tsm, 0-200 ft, pre Kirkwood Formation,Tkw, 0-600 ft, gray and sists largely of tough, blue or sand, clayey sand, and blue clay; dominantly clayey silt and silty clay, brown clay, silt and fine micaceous quartz gray clay. marine (Miocene). also very fine sand, shells and Forami- sand; estuarine and marine (Miocene). nifera; marine; conformable lower boundary (Miocene).
Choptank Formation, Tck, 20-105 ft, Choptank Formation, Tck, 0-260 ft, gray fine sand, sandy clay, and sand con and brown sand and clay containing taining fossiliferous layers; marine shell marl and Foraminifera; marine; (Miocene). conformable lower boundary (Miocene).
Calvert Formation, Tcv, diato- Calvert Formation, Tcv, 20-180 ft, Calvert Formation, Tcv, 15-680 ft, gray maceous and sandy but less sandy clay and fine sand, fossilifer diatomaceous silt and clay containing fossiliferous than the York- ous, contains dm to maceous earth; lenses and thin sheets of gray sand, shell town Formation. marine (Miocene). beds, and Foraminifera; marine (Mio cene).
Chickahominy Formation, Tcy, 0-80 ft, Piney Point Formation, Tpp, 0-60 ft, Chickahominy Formation, Tcy, 80-170 ft, Piney Point Formation, Tpp 0-60 ft, coarse consists of gray marl beds containing sand, slightly glauconitic, contain brown glauconitic clay. Aquiclude to fine glauconitic sand and greenish clay; subordinate glauconite and pyrite. ing intercalated "rock" layers (Mio (Eocene). marine; contains fossils of Jackson age Highly foraminiferal; marine; known cene). (Eocene). from well cuttings only (Eocene).
Piney Point Formation, Tpp, 0-220 ft, a white quartz sand and glauconitic green- sand grading into brown shales; marine; contains foraminifera. Conformable lower boundary (Eocene).
Nanjemoy Formation, Tn, gray marl, Nanjemoy Formation, Tn, 40-240 ft, Nanjemoy Formation, Tn, 0-295 ft, Snark River Marl, Tsr, 0-25 ft, fine glauco glauconite and quartz sand, and thin glauconitic sand containing clay blackish-green highly glauconitic sand, nite and light-colored clay; marine (Eocene). limestone beds. Includes pink Marl- layers. Basal part is red or gray silt, and clay. Conformable lower boro Clay Member at base (Eocene). clay (Eocene). boundary; marine (Eocene). Manasquan Formation, Tmq, 0-25 ft, fine glauconitic sand interbedded with greenish- white clay; marine; a leaky aquiclude (Eocene). HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A5 TABLE 1. Stratigraphic units of the northern part of the Coastal Plain Continued
Virginia Southern Maryland Delmar Peninsula New Jersey
Aquia Formation, Ta, 0-125 ft, glauco- Aquia Oreensand, Ta, 30-203 ft, glau Aquia Formation, Ta, 0-230 ft, green glaa- nitic marl and basal quartz sand beds. conitic greenish to brown sand, con conitic quartz sand containing a few No unconformity with underlying taining indurated ("rock") layers in lenses of clay, shell fragments, Forami- Mattaponi Formation (Eocene). middle and basal parts (Eocene). nifera, and hard beds; marine (Eocene).
Brightseat Formation, Tb, 0-40 ft, Brightseat Formation, Tb, 0-300 ft, alter Vincentown Foimation, Tvt. 0-100 ft, cal gray to dark-gray micaceous silty nating hard and soft beds of gray clay careous fossiliferous sand and glauconitic and sandy clay (Paleocene). and sparsely glauconitic sand containing quartz sand. Semiconsolidated; marine Foraminifera and shells; marine; regional (Paleocene). unconformity (Paleocene).
Mattaponi Formation, Tkm, 0-600 ft, Hornerstown Sand, Tht, 0-30 ft, glauconite, mottled clay, glauconitic sand and clay, and quartz sand; fossiliferous; marine marl, and thick basal quartz sand. (Paleocene). Deposited in estuaries and bays. Monmouth Formation, Kmo, 0-230 ft, Red Bank Sand, Krb, 0-20 ft, discontinuous dark-green and brown glauconitic sand bodies of reddish-brown fairly coarse sand. Monmouth, Kmo, and Matawan Kma, and gray clay containing shells and Littoral marine. Upper Cretaceous, undifferentiated, Formations, 20-135 ft, dark-gray to Foraminifera; marine; lower boundary 0-200 ft, red, brown, gray and blue black sandy clay and sand contain conformable. Navesink Formation, Kns, 0-40 ft, glauconitic clay, gray sand, and slightly glauco ing some glauconite. Basal part is green marl, lenses of sand and clay, and a nitic sand containing indurated layers. lighter in color and less glauconitic. basal bed of shells; marine. Deposited in near-shore marine waters. Sediments have a continental aspect, Mount Laurel Sand, Km I, 0-60 ft, salt-and- although they contain marine fossils, pepper-colored glauconitic quartz sand: are highly variable in composition, and marine. contain bright-colored strata.
Matawan Rormation, Kma, 0-220 ft, white Wenonah Formation, Kw, 0-50 ft, brown silty chalk, glauconitic sand and clay, fine to medium quartz sand, slightly and gray micaceous fine sand and con glauconitic; marine. glomerate; marine. Marshalltown Formation, Kmt, 0-40 ft, black sandy clay and lenses of glauconitic sand; marine; confines the Englishtown Formation.
Englishtown Formation, Ket, 0-140 ft, yellow fine to pebbly quartz sand, slightly micaceous and glauconitic. Slightly con solidated; contains ledges of hard sand stone; lagoonal and marine.
Woodbury Clay, Kwb, 0-50 ft, bluish-black tough micaceous clay, not glauconitic; marine.
Merchantville Formation, Kmv, 0-60 ft greenish-black micaceous clay and sandy clay, glauconitic; marine; in conjunction with the Woodbury Clay and the Marshall- town Formation, forms an effective, extensive confining bed.
Magothy Formation, Km, 0-140 ft, Magothy Formation, Km, 30-140 ft, white Magothy Formation, Km, 0-50 ft, alternating light-gray to white sand and fine yellow and gray sand interlaminated beds of gray clay and gray to brown sand, gravel, containing interbedded clay with gray and brown shale, containing commonly lignitic. Estuarine, marsh, layers; contains pyrite and lignite; lignite and carbonaceous matter, but no and littoral marine. nonmarine. animal fossils; nonmarine in the south but estuarine and littoral marine in the north; unconformable lower boundary.
Raritan Formation, Kr, 0-100 ft, inter- Raritan Formation, Kr, 0-1,700 ft, inter Raritan Formation, Kr, 0-900 ft, varicolored bedded sand and clay containing calated thin sand and shale. The sand red, gray, and yellow tough clay and ironstone nodules; locally contains is lenticular, crossbedded, generally yellow silty fine to emdium quartz sand. indurated layers; nonmarine. gray, fine grained, micaceous, and lig- Contains a few thin beds of shells and nitic. The shale is mottled pale gray, lignitic sand. Predominantly fluvial and brown, and red in the upper section and deltaic; contains a few thin marine beds. gray brown in the lower. A few beds that contain Foraminifera and macro- fossils with glauconite are marine tongues; the formation is predominantly nonmarine but downdip becomes deltaic and estuarine. The lower boundary is unconformable.
7)90-196 A6 HYDROLOGY OP AQUIFER SYSTEMS
TABLE 1. Stratigraphic units of the northern part of the Coastal Plain Continued
Virginia Southern Maryland Delmar Peninsula New Jersey
Potomac Group, Kp, 0-1,000 ft, inter- Patapsco Formation, Kpt, 100-650 ft, Patapsco Formation, Kpt, and Arundel bedded clean arkosic, white to gray interbedded sand, clay, and sandy Clay, Ka, 130-2,100 ft, medium- to fine quartz sand and light-colored clay clay; color variegated but chiefly grained white sand in the upper part, containing few lenses of gravel. Del hues of red and yellow; nonmarine. but coarse and gravelly in the lower 600 taic sediments deposited in fresh to ft. Clay shales and sandy shales are slightly brackish waters. gray and brown in the upper part, varie gated gray, red, brown and green in the middle part, and olive green and gray in the lower part. Generally nonfossil- iferous. Nonmarine and deltaic. Lower boundary not conformable.
Arundel Clay, Ka, 25-200 ft, red, brown, and gray clay; nonmarine; in places contains ironstone nodules and plant remains.
Patuxent Formation, Kpx, 100-450 ft, Patuxent Formation, Kpx, 125-2,300 ft, chiefly gray and yellow sand con poorly sorted fine to very coarse sand and taining interbedded clay; kaolinized gravel, lenticular and crossbedded. Var feldspar and lignite common; non- icolored shales. Fluvial and alluvial-fan marine, locally clay layers predomi deposits. Lower boundary not con nate. formable. Rocks of pre-Cretaceous age, pk, undifferentiated complex of gneiss, schist, gabbro, granodiorite, serpentine, and marble containing pegmatitic dikes of form platform upon which the sediments of the Coastal Plain were deposited.
The positions of the salt-water interfaces are shown considerations (Barksdale and others, 1958, p. 109-111). in figure 2. They represent the westward extension of The probable position of the salt-water interface in the ground water containing about 350 ppm (parts per mil Earitan and Magothy Formations was determined by lion) or more chloride and referred to as "saline or salt consideration of the head of the fresh water in the out water" in this report. No analyses are available which crop area and the relative density of the fresh and salt indicate that any of the saline ground water has chlo- water. All available chemical data verify the general rinity concentrations as great as that of sea water. position. This interface has been used in the con For the regional discussion and the illustrations struction of the flow diagram (fig. 3) for the Cretaceous presented here, salt-water intrusions that result from sediments, and its theoretical position is indicated on the artificial ground-water withdrawal are considered to be fence diagrams (section B-B'). local details that do not appreciably alter the original The southern line, in New Jersey (fig. 2), is a possible natural relationship between fresh water and salt water. position of the salt-water interface in the Miocene sedi In addition, the shallow Pleistocene deposits contain ments. (See section O-A', pi. IB.) Fresh water is salt water in some areas. This occurrence is neither obtained from a depth of about 800 feet at Atlantic discussed nor illustrated here. City. In Cape May County, salt water is obtained at In southern Virginia and in Maryland, the position less than 500 feet (Gill, 1959, fig. 7). of the interface represents the landward limit of salty In New Jersey, the southern line, which represents water in the Cretaceous and Tertiary sediments. Fresh the interface in the Miocene sediments, is more com water can be obtained from aquifers at depths of more parable to the line drawn for Maryland and Virginia. than 1,000 feet in the area west of this line. Except for There is no known occurrence of salt water in the deep local salt-water encroachment into some shallow sedi Tertiary sediments northwest of this line. Those sedi ments, the water in these deposits is fresh. East of ments in which the bulk of the water is fresh and those the interface in Virginia and Maryland, fresh water sediments in which the water is mostly saline are cannot be obtained from depths much greater than indicated on plate IB. The distribution of pre- about 500 feet. In Virginia, south of the York Eiver, Cretaceous bedrock and the thickness of the Coastal the limiting depth of fresh water is less than 500 feet Plain deposits also is shown. The thickness of the (Cederstrom, 1943a, pi. 3); but near the coast in Dela Cretaceous deposits is many times greater than that of ware, fresh water locally extends as deep as 700 feet the overlying Tertiary deposits. The bedrock surface (Sanford, 1911, p. 78). was compiled from the tectonic map of the United In New Jersey two salt-water interfaces are shown. States (1960). The northern line indicates the interface in the Magothy The shape of the salt-water interface is schematic; and Earitan Formations and is based on theoretical however, it is patterned after the shape observed in HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A7
EXPLANATION
200-300 >300 Altitude in feet Interface between the fresh water and salt water (350 ppm Cl) for the Cretaceous sediments. In New Jersey the interface is shown for the Raritan-Magothy For mations Interface between the fresh water and salt water (350 ppm Cl) in the Tertiary sedi ments Landward from these interfaces, fresh water can be produced from depths as great as 1000 feet. Seaward from these inter faces, salt water can be produced from depths of less than about 500 feet and fresh water does not exist at depths greater than about 500 feet for the stratigraphic se quence as indicated
FIGURE 2. Map showing the relation of topography to landward extent of salt- and fresh-water interfaces in the Cretaceous and Tertiary deposits. A8 HYDROLOGY OF AQUIFER SYSTEMS
areas of salt-water encroachment into aquifers where (Kohout, 1960, fig. 3) or after the shape identified in g=rate of flow of water through a unit cross-sectional area of porous material tidal estuaries. From plate IB it is seen that probably P= permeability of porous material 80 percent of the Cretaceous and Tertiary section of the 3ft/3D=rate of head change along the flow path ; Coastal Plain contains saline ground water. This con and from the Ghyben-Herzberg principle : stitutes a large potential source of supply in case fresh h=(S-l)H (2) ground-water supplies may not be adequate for future where demands (Krieger and others, 1957, p. 34). ft = head of fresh water above sea level S=density of salt water Several factors determine the positions of salt-water- H =depth of salt water below sea level. fresh-water interfaces in coastal areas. A major con On the basis of the two preceding statements and trol is the distribution of fresh-water head in the re certain idealized conditions, Harder and others (1953, charge and discharge areas. The fresh-water head is p. 44) derived the following equations to express the influenced by topography, thickness of sediments, relation of these factors to the length (Z) of the salt amount of recharge and discharge, and vertical and water wedge: horizontal changes in permeability. (3) The relationship of several factors that determine the position of fresh-water-salt-water interfaces in coastal - <«->> (4) aquifers can be seen from a statement of Darcy's law: Where M is the thickness of the aquifer. The termin ology is illustrated in the accompanying diagram (after (1) Harder and others, 1953 p. 7). Piezometri£
|/,=fS-lj
Aquifer
Equation 4 expresses the length of- the salt-water the density and thickness terms. However, it is obvious wedge as a function of permeability, flow of fresh from the diagram that a decrease in fresh-water head water, relative densities of the two fluids, thickness of (h) will cause a corresponding decrease in depth of salt sediments, and fresh-water head, assuming the follow water below sea level (H) , which has the effect of in ing conditions: creasing the length of salt-water wedge. 1. Steady-state flow. These general relationships are shown on plate IB 2. A horizontal confined aquifer discharging only at and in figure 2. For example, the salt-water interface the submarine outcrop. in the Miocene sediments in New Jersey is farther sea 3. Absence of tidal fluctuations. ward than the interface in the Cretaceous formations 4. No salt-water circulation due to dispersion or dif because the head in the recharge area of the Miocene fusion. sediments is higher than in the recharge area of the From equation 4 and the diagram it can be seen that Cretaceous formation at low altitudes along the Fall the length of the salt-water wedge is directly propor Zone. The interface in the sediments of Miocene age tional to the permeability and thickness of the sediments is farther seaward than the extent of most of the fences and that it varies inversely with fresh-water head and shown on plate IB; however, the relative position of quantity of flow. By the integration steps of the deriva the two interfaces is shown in section O-A. tion the terms related to head have been combined with In Delaware and in northern Maryland (section HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A9
E-E'} the salt-water interface is close to the Fall Zone Salem, N.J. Salt water in some of the marine forma primarily because of the absence of highlands near the tions may be in part residual water or ions that have outcrop area and the lower heads in the aquifers. One not been completely flushed by fresh water. However, of the highest outcrop areas (alt, 175 ft) of the Creta owing to postdepositional chemical reactions, the orig ceous formations is northest of Washington. The Cre inal chemical character of the water or its source in time taceous sediments and the overlying sediments also or space cannot be determined from the present chemis receive recharge in a highland area southeast of Wash try of the water (Chaves, 1960, p. 369). ington. The existence of these high land masses and The presence of salt water may also be partly due of the highland region along the northern neck of to entrance of sea water during the Tertiary and Virginia, between the Rappahannock and Potomac Pleistocene submergence of the Coastal Plain. Sanf ord Rivers, allows the fresh-water head to become high (1911, p. 82-83) stated this idea as follows: enough to maintain the salt-water interface at a distance In periods of elevation underground circulation has been from the Fall Zone (section G-G'} greater than that to quickened and fresh water has gradually leached marine de the north (section F-F', pi. IB). posits and forced out any original sea water. In periods of In the central part of Virginia along the Fall Zone, depression the outcrops of fresh-water bearing beds have been the altitude on the surface of the Coastal Plain sedi saturated by sea water and blanketed by marine deposits. Another period of elevation has started fresh water down the ments is approximately 175 feet, which is about the dip, displacing sea water, leaching marine deposits, and forcing same as that of the recharge area in Maryland. How the salt but freshening solutions into the underlying beds. Thus, ever, the streams have much wider flood plains and the a bed that originally was a fresh-water deposit may have been uplands are more deeply dissected. This advanced repeatedly invaded by salt water from above and the present stage of erosion facilitates the discharge of ground salinity of the water in a particular area is to be regarded as connected with the last invasion of salt water rather than with water locally and prevents formation of high fresh any sea water imprisoned in the beds at the time of deposition. water heads under the Coastal Plain. Because of these Some of the deep salt water may also be due to solu fresh-water heads fresh water and salt water are bal tion of minerals and to the concentration of ions by anced in an area closer to the Fall Zone (section /-/', Pl. IB). filtration by the clays. Although no analyses are avail able for this part of the Coastal Plain, on the basis of Because of the mutually interrelated effects of perme work done in other areas (Spangler, 1950, p. 106; ability and thickness of sediments on the distribution of Meents and others, 1952, figs. 4-13) the deeper water head and quantity of water flow, generalization con (below 1,500-2,000 ft), certainly is more concentrated cerning their relative significance in determining the than sea water. The specific processes involved are not position of the salt-water wedge cannot be made within sufficiently understood to satisfactorily explain the the scope of this study. origin of brines. The dominant controls thus far iden In view of the preceding relationships, an obvious tified are the relative solubilities of minerals in concen conclusion is that in a region of uniform rainfall the trated solutions and the effect of clays undergoing com position of the salt-water-fresh-water interface in con paction and ion exchange. The membrane properties trolled primarily by the topography of the region, the of clays may, as has been postulated by several workers extent of erosion, relative thickness of sediments, and (de Sitter, 1947; Bredehoeft and others, 1963), lead to the permeability of material in the beds within the area the exclusion of ions from water flowing across a mem of ground-water flow. brane. That is, where the clays act as semipermeable FACTORS AFFECTING OCCURRENCE OF SALT WATER membranes the water moves through and is discharged while the ions remain behind and are concentrated. Saline water may accumulate in geologic formations by any of the following processes: Retention of ions GROUND-WATER FLOW PATTERNS from salt water trapped at the time of deposition; in A generalized ground-water flow pattern for the trusion of salt water after deposition due to change in Cretaceous sediments of the Coastal Plain is shown in sea level or in discharge; solution of minerals and con centration of the constituents by filtration by the clays; figure 3. The western boundary of the flow patterns and recharge by atmospheric precipitation containing was established along the outcrop of the sediments near ions. the Fall Zone and the eastern boundary along the salt An objection to the hypothesis that the deep salt water interface in the Cretaceous deposits. The num water is the original water in which the sediments were bers along these boundaries represent head values. They deposited is that salt water occurs in the Potomac group were obtained in the outcrop area by measurement of of fresh-water origin, as at Chestertown, Md., and at water levels; along the salt-water interface they were A10 HYDROLOGY OF AQUIFER SYSTEMS
39 WASHINGTO
EXPLANATION RICHMOND 20 Head values, in feet, for area indicated
Approximate position of salt water as described on figure 2
Approximate position of outcrop of the Cretaceous sediments
Lines o'f equal head
Horizontal component of flow
40 MILES CAROLINA 76°
FIGURE 3. General pattern of ground-water flow in the Cretaceous sediments. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN All obtained from historic records that indicate the approx head in the overlying Tertiary sediments. The water imate altitudes of the peizometric surface as defined by is discharged into the Raritan Bay area, along the Dela flowing wells in those areas. Because the maximum ware River, and perhaps eastward from the coast height to which the water would rise was not measured, through submarine springs. these are minimum head values for defining the original It is evident that the outcrop area of artesian aquifers natural conditions. can function either as a discharge area or as a recharge In drawing and in analyzing the pattern of ground- area. This, of course, demonstrates that the water water flow, the salt-water interface was treated as an moves updip (that is, to the west or northwest) in many impermeable boundary that is, as a limiting flow line. parts of the Coastal Plain. By definition no fresh water can cross this boundary. Figure 4 shows relation of topography to the general If fresh water could move into the salt water, the ef ized flow pattern in four selected cross sections. The fects would be dilution of the salt water and migration direction of movement is based on the interpretation of of its boundary. Therefore, in effect the salt-water piezometric surface shown in figure 3 and other water- interface marks the limit of horizontal flow of the fresh level maps and measurements made for local areas. water. Some of the water that is shown in section E-E' as The flow pattern was drawn by using an electric being discharged updip has moved laterally southward analog model in which head values are simulated by from the recharge areas in New Jersey and northern electrical potentials (voltage) applied to a sheet of Delaware. Some of it has been recharged through the graphite-coated paper having uniform resistance. After Tertiary sediments of the central part of Delaware. building the model the electrical potential was con The cross section H-H' shows that much more of the toured between the boundaries to describe the configura water is discharged updip to the west and some flows tion of the piezometric surface. Flow lines were uwpard to the east over the salt-water interface. In sketched in orthogonally to the equipotential contours southern Virginia the ground-water flow is restricted to form rough squares, according to standard proce by the shallow bedrock and by the proximity of the salt dures for constructing flow nets (Oasagrande, 1937). water. However, owing to the lack of data, primarily values Throughout much of the eastern part of the Coastal for natural discharge of ground water, this illustration Plain the rechange is from the local rainfall. The is not a rigorous flow net and cannot be used for quanti major movement of ground water during wet periods is tative studies of aquifer transmissibility and rates of primarily downward to the water table; during dry water movement. In constructing the model it was periods it is upward. Of course, the ground water is not possible to take into account the amount of upward discharged locally into many streams and estuaries. vertical leakage. Hence, this flow pattern shows the The water that is locally recharged and discharged has direction of ground-water movement in the Coastal little effect on the overall chemistry of the water with Plain as if there were no upward vertical leakage. This the possible exception of dilution in the upper beds. is not to imply that the major ground-water discharge of the Coastal Plain sediments is not upward into the HYDROCHEMICAL FACIES overlying sediments but only that the flow pattern is DEFINITION shown for two dimensions. The vertical movement of The concept of hydrochemical facies has been used ground water is shown in figure 4. (Seaber, 1962; Morgan and Winner, 1962; and Back, This method of construction, however, is adequate 1960) to denote the diagnostic chemical character of to demonstrate important general features of ground- water solutions in hydrologic systems. The facies re water movement. The recharge areas of the Cretaceous flect the effects of chemical processes occurring between sediments are evidently in New Jersey, Delaware, the the minerals within the lithologic framework and the area between Washington and Baltimore, the high area ground water. The flow patterns modify the facies and of southern Maryland, and along the Fall Zone in Vir control their distribution. This definition of hydro- ginia. The areas of discharge in the outcrop area are chemical facies is a paraphrase of the definition of sedi indicated by the flow lines and by the low-head values. mentary facies given by Moore (1949, p. 8) : "sedimen In New Jersey this flow pattern is quite similar to tary facies are areally segregated parts of differing nat that for the Magothy and Raritan Formations. The ure belonging to any genetically related body of errors introduced into the flow pattern owing to lack sedimentary deposits." of modeling for upward vertical discharge are small The term "geochemical facies" has been used by for the New Jersey area. Upward vertical leakage is Teodorovich (1949) and Pustalov (1933, 1954) to de not a major factor in New Jersey owing to the high fine different sedimentary environments by means of A12 HYDROLOGY OF AQUIFER SYSTEMS
VERTICAL EXAGGERATION X 100
FIGURE 4. Sections showing the vertical component of the major ground-water flow. Location of sections shown in figure 1. HYDROCHEMICAL FACIE S, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A13 specific mineral indicators of oxidation-reduction po cal types of water. The uppermost zone is character tentials and pH. Adams and Weaver (1958) proposed ized by a high degree of water circulation and well- that "geochemical f acies" of sedimentary rocks be de leached rocks and sediments. The water is of the bi fined in terms of the thorium-uranium ratio. Keith carbonate type and has a low dissolved-solids content. and Degens (1959, p. 40) used the term "chemof acies" In the intermediate zone water circulates less, the dis to designate all the chemical elements that are collected, solved-solids content is higher, and the water is of the precipitated, or adsorbed from the aqueous environ sulfate type. The lowermost hydrodynamic zone is a ment, or fixed by chemical reactions in the bottom muds, "stagnant" regime in which rocks are unleached and as a basis for differentiating between marine and fresh the water is highly mineralized and primarily of the water sediments. chloride-sodium type. The term "hydrochemical f acies" was used previously The hydrodynamic zones have been subdivided within by Chebotarev (1955, p. 199) for a column heading in a the hydrochemical zones by the Russians to produce table; however, he did not define the term and used it hydrogeochemical zones. The following vertical suc only to indicate concentration of dissolved solids that cession of hydrogeochemical zones was established by is, low-saline f acies, transitional-saline f acies, and high- Kravtzov in the coal-bearing measures of the Donetz saline f acies. basin (Kamensky, 1958, p. 285) : Hydrocarbonate (bi Many Russian scientists have contributed to formula carbonate)-calcium water, hydrocarbonate-sulfate-so- tion of the "principle of hydrochemical zones." The dium mixed water, sulfate-sodium water hydrocarbon concept of hydrochemical fades, as used in this report, ate-sodium water, hydrocarbonate-chloride-s odium is a refinement of this approach and can be considered, water, and possibly a zone of highly mineralized chlo in part, as subdivision of major zones. According to ride-sodium water. The term "hydrogeochemical the usage by some Russians, hydrochemical zones cover zones" is used to emphasize the relationship between the large regions and are segregated according to the pre chemistry and movement of water. dominant anion. For instance, the European part of The term "hydrochemical f acies" includes all the con the Soviet Union is segregated into five hydrochemical cepts signified by hydrochemical zones, hydrochemical zones (Garmonov, 1958). The zone (1) of hydrocar- microzones, hydrodynamic zones, and hydrogeochemi bonate (bicarbonate)-siliceous water coincides with the cal zones. Accordingly, one term can be used in soil-tundra zone, where the average yearly temperature stead of four. is 0°C. This water is low in dissolved solids. The The terminology used to designate the hydrochemical zone (2) of hydrocarbonate (bicarbonate) ^calcium f acies of the Atlantic Coastal Plain (Back, 1961b) is water covers an extensive area in which there are many shown in figure 5 and in table 2. A further refinement different geologic deposits, most of which contain cal careous materials. Sulfate and chloride occur in the is used here to subdivide a particular f acies into a chem southern part. Cation exchange also results in the cre ical type of water on the basis of the dominant ion ation of hydrocarbonate-sodium water in this zone. within the f acies. For example, water showing the cal The zone (3) of sulfate and chloride-sulfate water cium-magnesium facies may be of either the calcium roughly coincides with the central and southern parts of type or the magnesium type. On the other hand, either the steppes and is characterized by a predominance of the facies or the type may be combined to designate the evaporation over precipitation. Calcium is the domi overall chemical character of the water (for example, nant cation. The zone (4) of chloride water occurs in TABLE 2. Classification of hydrochemical facies of the Atlantic the area of the Black Sea lowland and in the northern Coastal Plain a part of the Crimean peninsula; a second area is the Caspian lowland. The first area contains saliferous Percentage of constituents, in equivalents per million soils, salt licks, and salt marshes. The 'Caspian low land is an area of desert and semidesert in which the Ca+Mg Na+K HCOs+COs Cl+SO," water is the chloride-magnesium-sodium type. Zone Cation facies: 90-100 0<10 (5), in which the water has a low content of dissolved 50-90 10<50 10-50 50<90 solids of the hydrocarbonate-calcium type, is in the 0-10 90- 100 Anion facies: mountainous regions of the Crimea and the Caucasus. 90-100 0<10 Bicarbonate-chloride sul In addition to the geographic hydrochemical zones, fate.--.-. -.---_----____.- 50-90 10<60 C hloride-sulfate-bicar- several scientists (Kamensky, 1958, p. 285; (Chebo 10-50 50<90 C hloride-sulfate.. _ ...... 0-10 90-100 tarev, 1955, p. 200) have discussed three vertical hydro- dynamic zones that are characterized by certain chemi- « Modified from Back (I961b, p. D-381). ' May include some NOs and F. 790^196 O 66 3 A14 HYDROLOGY OF AQUIFER SYSTEMS
FIGURE 5. Water-analysis diagram showing hydrochemical facies, in percent of total equivalents per million. water of the sodium type and chloride type would be show isopleths of chemical constituents within certain classified as sodium chloride character). formations. Trilinear and similar diagrams have long been used PROCEDURES AND MAPPING TECHNIQUES to study the chemistry of water. Emmons and Har- Significant characteristics of hydrochemical facies rington (1913) used two triangles, one for cations and can be illustrated by methods similar to those used in one for anions, with each vertex representing 100 per lithofacies studies trilinear diagrams that show the fa cent of a particular ion or groups of ions, as is often cies present in an area or in formations, fence dia used in petrographic studies. Hill (1940; 1942, p. 1517) grams that show the facies distribution, and maps that published a trilinear diagram which added to the origi- HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A15 nal two triangles a diamond-shaped area in which the 6, show that the sodium and bicarbonate facies are two points plotted in the triangles are projected into the dominant in most of the area. The water from the diamond and are plotted as a single point. Piper counties along the Fall Zone is of a mixed character. (1944) independently developed a similar diagram that Two analyses from Nansemond County (53, 54) show has undergone minor changes and is used in this and the presence of saline water. Typical analyses of other recent papers. water from the Cretaceous formations are shown in Trilinear diagrams were used in this study as the table 3. The index numbers in all the tables refer the first step in the classification of the hydrochemical analyses to the corresponding trilinear water-analyses facies present. They were used to determine in which diagrams. The well numbers given in the tables refer stratigraphic units waters were sufficiently close in com the analyses to the fence diagrams. position to assume hydrologic connection between The hydrochemical facies of the Mattaponi Forma stratigraphic units to permit study as a hydrochemical tion of Cretaceous and Paleocene age in Virginia are unit. Therefore, the analyses were converted from shown in figure 7. As in the Cretaceous formations, parts per million to equivalents per million, and the per the sodium and bicarbonate are the major cation and centages of equivalents were computed and were plotted. anion facies. The one analysis reflecting the calcium- Because only a limited number of analyses can be plotted sodium facies is of water near the Fall Zone. The on any one diagram, the analyses were divided: first samples from York County indicate the saline character by States, second by formation or groups of age-related of the water in the Mattaponi Formation in that area. formations, and third by county boundaries. Typical analyses are given in table 4. Isometric fence diagrams (Back, 1961b) were selected The hydrochemical facies of Cretaceous formations in as the most effective means of illustrating the geo Maryland, as plotted in figure 8, shows that the water graphic and stratigraphic distribution of the hydro- from these formations represents all major types. chemical facies. A base-fence diagram was prepared Some individual formations within the Cretaceous to show the topography in cross section and the strati- System contain the full range of facies. Selected graphic units from land surface to 1,000 feet below sea analyses of water (table 5) show the range of concentra level. Twelve parallel cross sections trending nearly tion of ions in the areas where the Cretaceous forma perpendicular to the strike of formations were arbitrar tions are used extensively as aquifers. The trilinear ily selected. Then, 3 northwest-trending longitudinal diagram (fig. 8) shows that most of the water from sections perpendicular to the 12 lateral sections were Anne Arundel and Prince Georges Counties, in the prepared. The location of wells from which water higher piezometric area, is primarily of the calcium analyses were used in this study is shown on the fence type. The availability of calcareous material deter diagrams. Most of these wells are within 5 miles of mines whether the anion facies is of the sulfate or the particular cross section to which they are projected. bicarbonate type. On the Eastern Shore, down- The true altitude of the well top was plotted; hence, gradient, the water has the sodium bicarbonate on the fence diagrams the well top may not coincide character. with the land surface shown. The wide variability of the hydrochemical facies in The concentrations or percentages of the constituents the Raritan and Magothy Formations in New Jersey is selected as being most informative were: Sodium and shown in figure 9. Representative analyses are given potassium as percentage of total cations, in equivalents in table 6. In the area of the piezometric high of Mer per million (cation facies); bicarbonate and carbonate cer and Middlesex Counties, the water is primarily of (where present) as percentage of total anions, in equiv the calcium-magnesium and chloride-sulfate facies. alents per million (anion facies), sum of determined Downgradient in the general discharge area along the constituents, in equivalents per million; concentration Delaware River in Camden and Gloucester Counties of the chloride ion, in parts per million; and concentra the bicarbonate facies is dominant. The increase in bi tion of the bicarbonate ion, in parts per million. carbonate may be due to the solution of calcareous ma terial in the Tertiary sediments underlying the piezo OCCURRENCE OF HYDROCHEMICAL FACIES WITHIN STRATIGRAPHIC UNITS metric high to the east. The water from Salem County and parts of Gloucester County is of the sodium type CRETACEOUS SEDIMENTS primarily owing to the ion-exchange process and to The hydrochemical facies of the undifferentiated presence of salt water from the river and from the ex Cretaceous formations in Virginia, as plotted in figure tensive body of saline ground water. A16 HYDROLOGY OF AQUIFER SYSTEMS
EXPLANATION Index numbers listed by county /- 8 Spotsylvania 9 Stafford 10-13 Henrico 14-16 Westmoreland 17, 18 Richmond 19-23 Sussex 24,25 Hanover 26 King and Queen 27-30 Prince George 31-34 Southampton 35-37 Surrey 38-41 Northumberland 42-47 Isle of Wight 48-54 Nansemond 55, 56 New Kent Bold numbers refer to analyses given in table 3
' ft £,O/ *-£.*. Ml (6* / S\\ ^'PHTN 3 7 /13 212948 /33 \'^51 c? 24,55,56 / 1,13 21 29^' 28,35,45,49 CATIONS ANIONS
FIGURE 6. Water-analysis diagram for the Cretaceous formations In Virginia. K K County:Sussex County:Stafford County:Westmoreland County:KentNew GeorgeCounty:Prince County:Nansemond « o! £ »i Walkers.. . GeorgePrince Brandon..____. City.....Suffolk Montross...... Jarratt....------... Waverlv--__..-_ Fredericksburg_. Hopewell_____ Cypress...... Location Wakefield...... Do... -... CourtHouse..... Burrowsville--...... Chuckatuck ! is ! i O& « QS g^ < §4 fs i>^ g.
eg en to Index No. 01 CO 52 t3 to 1 CO h-> Well No. Cft to S 2S c . co S S 8S S * Ol I-1 «H g > "S- C 0 0 S5 ^0 % r> s ^ 8 3 1? 9 co to co Date of collection » ' .« O &> JS .>- Ol to o o » Cft Cft Total iron (Fe) S * 8 8 S fc S5 is 8 8 g -1 Ol 8 !- *^ h- a pot*? So. 5 co . *-. co w§ Calcium (Ca) cfc to »^ go 55 £°° t- WO tO S t^ o o co Ol O co o to to Magnesium *. to -a oo woo g; 01 fe~8 S CT 8° ijcog-, cp o to cp S to to co O O Cft g Cft to Cft co to CO !- 1 ' OO piS . 50 cootoo co -1 CnCOCO . w^^S Sodium (Na) f Cft *. h- h--a 01 co s a s co -~i O <35 Cft «* Ol g s s b epmppm;lower,Upperfigurein . f. pi . b5 * 5 * Cft h-» O h-» 00 O O i 01 1^ i eft Potassium (K) 1 8" CO Cn Cn to co to 5°° -I g w "^1 t<3 Bicarbonate JO OO ^J CO g 5£ O 0 0 o o -o o 000 0 . o. o co o Carbonate 5 888 8 888 888 8 w * 8 S C«8 (C03) . r> .«..». w p ^ CO Cft OD CO 01 ^ eft co -I Oi Cft -J Sulfate (SO,) h->Ol tOOJH-OOO Cft tO h->O >- * o eo i- ti S CT Cft o eo eft 8 OD -*I t-1 JS S?°° 5*^°- Jg S° to oo to to woo G to co eo 01 to g Chloride (Cl) OCft £3*-OCOg>tO ooo ^°'S? 0 5 00 O »^ O O O OD Cft Ol JS S S^ £ S S^ "^i Cft OD Ol to to ki 01 Cft. eo 0 h- *. QOOIOOO Ol- 1 OD 1 »^ S° o^o^g-, gogco gcfto^ Fluoride (F) CO O I-1 O S*S CT tO tO !- h- to ! Nitrate (NOs) £ M gSS°S co 8" S^S 1- 8° So ti^Soi 001 S CT i So g-gto g«ogo A18 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county /, 2 King George 3, 4 New Kent 5 King William 6 Northumberland 7-13 York /4-/9 Lancaster Bold numbers refer to analyses given in table 4 20 S> ^cT CATIONS FIGURE 7. Water-analysis diagram for the Mattaponi Formation in Virginia. County:York County: Westmoreland County:Richmond County:Northumberland County:Lancaster County:NewKent KingGeorgeCounty: KingGeorge StoneWhite - Irvington_.___. Do.. Fleeton_ . Walkers------ForgeProvidence Sealston.-___ f Stone...White----- Grove.___----- CampPeary..----- Leedstown.----_- wning.--Do------Avalon.---.-. .. House.-Court 1 Index No. =55*: to co oo oa *. CO I-" tO to co i to to n -J CO Well No. Cn to 00 CD Oi I-4 to 01 Oi *J to fc id. co Depth of well (ft Cn 00 -4 below land surface) 18! IS- Oi tO 1 g Sg h ig CH CH ^ o £ CH g 0 c S a | p CD 5 (C a. i' if* a. °> 3 5 I tO ju ,co oo Date of collection 00 00 00 00 00 oo oo 00 00 Oi 00 Oi *. Oi CO CO M ^ 00 CO PH Specific conductance CO 00 (micromhos at S S s to S S ! 81 25°C) Dissolved solids as s $ C33 (residue at 180°C) to -j 95 i i 1 t g a oa co ce >£! o Silica (SiO3) to co 00 * * o> Oi ifc. s a 8 s 5 sT N- Oi O ^? 10 i cp Total iron (Fe) 2 CO H^ Ci 8 g 01 o 53 g ° 2 . ^^-^ 00 I-" I-" oo oo os to -J CO tO i-CO CO Calcium (Ca) £00£ 0 g 1-1 tS COOJ 8^°-^ ° 1 o S o k^ 00 5 M o° § 5°° o 5. O> Oi W *t ^^ o i-" -o «o Magnesium [£QO to en COtO S-^S 00 00 on»k tooi (Mg) ars^s-' 00 CO Cn 5 M 8 Oo l-i ^- _ J5 ^ Sodium (Na) go ^ oo OOOiOlOl *.2 toco d CO g CO oo § *. K 3 00 s 8 CO 8 Potassium (K) o> to g° (X) *. CO CO S 5 S Oi t^OO -4 OS to ^4 CO OS Cw O5 O 0»8 *% Bicarbonate to *. *. 0 (HC03) 3 S SJ o 01 o S £ § s co S to IS COQO C7i I-1 I-* "CO tOOl >U g *K CO *. o co o o Carbonate hi CO l-i CO 5" g g 8 - a s g CO OJ 8 5° 8 8 (COa) CO q ~S g 53 ,-2~8-£ I-" 00 S 5 S 00 to w o O CO to co to co Sulfate (SO4) 0 g § -4 h- fc3 S S 01 1 i_i S to oo E^-lcoii to to o? to Ol I-" tO N- i | i _ C0_ tO ! ! ! ! *- k- k- to 1-1 >o " o ! ! ^-*.^-oo i . i i 000 8^ S°° I *.OO 3*8- g"g^ Fluoride (F) I > 00 Oi till CO Oi to 1-1 l-l o Nitrate (NO») oooo>oo> g^SgS" go gto ooiooi g-gO gtOOCO A20 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county /- 7 Anne Arundel 8-2 1 Prince Georges 22-27 Charles 28 St. Marys 29 Somerset All analyses given in table 5 Stratigraphic units 0 Magothy Formation Raritan Formation A Patapsco and Raritan Formations Patapsco Formation Patuxent Formation CATIONS ANIONS FIGURE 8. Water-analysis diagram for the Cretaceous formations in Maryland. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A21 TABLE 5. Analyses of water from the Cretaceous formations in Maryland [Location: The last well listed here is at Crisfield; the location of all the others is indicated on pi. 15 of Otton, E. G. (1955). Geologic formation: Kpt, Patapsco Formation; Kr, Raritan Formation; Km, Magothy Formation; Kpx, Patuxent Formation] g of(feetDepthwell surface) belowland | conductanceSpecific (residue°C)at180 Calcium(Ca) Sodium(Na) Bicarbonate Chloride(Cl) Fluoride(F) (°F)Temperature (micromhosat (HCOs) Carbonate Sulfate(SO)4 (NOa)Nitrate collectionofDate Dissolvedsolids (C0)3 Totaliron(Fe) 1~ Silica(SiOj) No.Well s~ 1 °C)25 l£ So I 3 a Upper figure in ppm; lower, epm ( 1.8 0.6 1.3 1.6 0 9 2 0 0.2 1 AA-Bf2... 318 Kpt May 1, 1951 58 4.1 54 34 9 2.5 \ .09 .05 .06 .04 .00 ...... 19 .06 .00 .00 6.2 2.3 6.1 1.4 2 14 7 .2 21 2 AA-Be45__ 67 Kpt-Kr Apr. 16,1946 56 4.7 114 75 2.8 .35 .31 .19 .26 .04 .03 .29 .20 .01 .34 6 3.6 2.2 1.4 10 26 1.8 .3 .1 3 AA-Cel... 213 Kpt-Kr Apr. 1, 1946 5.3 86 53 6.2 30 .30 .30 .10 .04 .16 ...... 54 .05 .02 .00 Anne Arundel 7.9 3.8 1.5 1.7 9 32 1.2 .2 .0 County. 4 AA-Dfl2__ 600 Kpt-Kr Mar. 20,1945 5.2 66 7.6 19 .39 .31 .07 .04 .15 ...... 67 .03 .01 .00 7.8 3.5 2.1 2.7 21 20 2 .3 .0 5 AA-Ce46.. 96 Km May 8, 1946 57 5.6 95 62 13 11 .39 .29 .09 .09 .34 ...... 42 .06 .02 .00 6.2 2.5 1.8 1.8 5 25 1.5 .3 .0 6 AA-Cfll.. 95 Km Apr. 16,1946 4.9 83 55 9.1 21 .31 .21 .08 .05 .08 ...... 52 .04 .02 .00 50 7.7 4.2 7.2 190 15 2.5 .1 1.5 7 AA-Ed8.. 265 Km June 28,1946 7.2 342 209 17 1.2 2.50 .63 .18 .18 3.09 ...... 31 .07 .01 .02 5.9 3.5 88 7.6 265 7.5 .5 .9 .8 22 Ch-Cc5._. 274 Kpt Apr. 2, 1952 7.9 411 265 19 1.9 .29 .29 3.83 .19 4.34 .16 .01 .05 .01 1.4 1.2 85 4.0 216 16 2.4 .7 .4 23 Ch-DdlO . 414 Kpt-Kr Mar. 7, 1951 8.2 365 245 19 .98 .07 .10 3.69 .10 3.54 ...... 33 .07 .04 .01 21 8.3 20 11 165 11 .9 .3 .5 Charles 24 Ch-Cf9... 679 Kpt-Kr Apr. 17,1952 7.5 268 158 11 .73 1.05 .68 .87 .28 2.70 .23 .03 .02 .01 County. 15 9.4 54 7.6 229 9 6.8 .1 .8 25 Ch-Dal... 210 Kpt-Kr Mar. 20,1951 7.4 371 244 32 1.8 . .75 .77 2.35 .20 3.76 .19 .19 .01 .01 (3.4 1.6 68 5.7 188 8.5 2.2 .3 .3 26 Ch-Eel8.. 300 Kr Jan. 27,1947 8.6 327 204 13 .96 \ .17 .13 2.96 .15 3.08 .18 .06 .02 .01 ( 5.9 2.4 70 8.6 210 13 1.2 .5 .7 27 Ch-Bcl2__ 234 Km Mar. 28,1950 7.8 357 224 16 .48 \ .29 .20 3.04 .22 3.44 .27 .03 .03 .01 ( 1.2 .1 60 .8 132 20 4.5 .1 1.6 8 PG-Ebl.. 603 Kpx Mar. 28,1949 52 8.0 255 180 24 .19 I .06 .01 2.65 .02 2.16 .42 .01 .13 .03 / 8.8 3.9 1.5 1.9 39 5.9 3.8 .0 .5 9 PG-Ddl7. 214 Kpx Apr. 18,1951 6.6 95 58 10 10 \ .44 .32 .07 .05 .54 ...... 12 .11 .00 .01 ( 2.8 1 6 .6 130 28 1.5 .3 1.1 10 PG-Fb7._ 263 Kpt Mar. 31,1949 60 8.1 265 209 32 .59 I -14 .08 2.61 .02 2.13 .58 .04 .02 .02 ( 3.4 1.6 50 4.8 123 24 1.5 .1 .8 11 PG-Ec26. 324 Kpt Mar. 31,1952 7.8 246 157 13 .95 I .17 .13 2.17 .12 2.02 .50 .04 .01 .01 ( 7.6 1.2 1.6 1.8 17 14 2 .2 .1 12 PG-Cf25._ 398 Kpt Apr. 17,1952 5.9 69 60 22 10 \ .38 .10 .07 .05 .28 ...... 29 .06 .01 .00 /20 6.8 3.5 2.6 73 22 2.4 .1 .1 13 PG-Cel8. 464 Kpt Nov. 4,1949 58 6.5 177 99 7.6 1.8 I 1.00 .56 .15 .07 1.20 .46 .07 .01 .00 (39 15 4.9 5.5 203 9.2 1.4 .1 .5 Prince 14 PG-Fd32. 490 Km Apr. 17,1952 7.8 320 184 12 .83 \ 1.95 1.23 .21 .14 3.33 ...... 19 .04 .01 .01 Georges (35 8.6 2.7 4.8 153 9.6 1.8 .2 .3 County. 15 PG-FdlO. 366 Km Apr. 14,1952 7.9 254 149 16 .28 I 1.75 .71 .12 .12 2.51 ...... 20 .05 .01 .01 (29 11 4.2 9.2 147 13 1.2 .3 .6 16 PG-FcH.- 150 Km Apr. 13,1950 54 7.7 263 149 13 1.8 I 1.45 .91 .18 .24 2.41 .27 .03 .02 .01 (37 7.9 3.4 1.2 158 13 1.5 .2 1.8 17 PG-Fd6_. 404 Km Mar. 25,1949 60 7.7 285 169 13 .21 I 1.85 .65 .15 .03 2.59 ...... 27 .04 .01 .03 (60 6.7 3.1 1.7 192 18 2 .3 .2 18 PG-Ef5 226 Km Apr. 15,1946 7.5 33 210 25 .31 I 2.99 .55 .13 .04 3.15 .37 .06 .02 .00 (50 5.2 5 1.9 178 10 2.1 .2 .2 19 PG-Ef3._. 366 Km June 6, 1949 6.9 307 183 15 14 I 2.50 .43 .22 .05 2.92 .21 .06 .01 .00 (17 2 3.1 1 58 13 2.5 .1 .8 20 PG-Cf2... 171 Km Mar. 22,1949 57 6.5 132 128 45 12.7 \ .85 .16 .13 .03 .95 ...... 27 .07 .01 .01 (21 2 3.4 2.1 40 18 12 .1 1.4 21 PG-Cel7. 118 Km Nov. 4,1949 59 7.5 149 108 4.4 .32 I 1.05 .16 .15 .05 .66 ...... 38 .34 .00 .02 St. Marys ( 1 .7 70 3.5 176 7.7 2.8 .6 .2 County. i28 8TM-Ef4. 661 Kr Jan. 16,1947 67 8.4 308 192 13 .31 I .05 .06 3.05 .09 2.90 .20 .16 .08 .03 .00 Somerset ( .5 1.2 294 3 586 12 51 70 2.2 1.3 County. }» 8om-Ec3~ 1,076 Km Oct. 19,1951 79 8.5 1,160 732 14 .12 I .03 .10 12.79 .08 9.61 .40 1.06 1.97 .12 .02 A22 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county 1-15 Salem Gloucester 45-49 Mercer 50-54 Middlesex 55-85 Camden 86-91 Monmouth 93-97 Burlington Bold numbers refer to analyses given in table 6 ANIONS FIGURB 9. Water-analysis diagram for the Magothy and Raritan Formations in New Jersey. Although the sulfate and chloride contents of the Formation and Wenonah Sand. Seaber (1962) has water in the Raritan and Magothy Formations of New done detailed mapping of the hydrochemical facies in Jersey are not appreciably different from those in the the Englishtown Formation. formations farther to the south, the extremely low con EOCENE FORMATIONS tent of the bicarbonate ion permits the development of the chloride-bicarbonate and the bicarbonate-chloride The water from the Eocene formations in Virginia, facies. as shown in figure 12 and table 9, is almost entirely of Figure 10 shows that water from the Red Bank Sand, the sodium bicarbonate character. A few analyses Mount Laurel Sand, and Wenonah Formation is pri show the sodium-calcium bicarbonate character. marily of the calcium bicarbonate character. Typical The hydrochemical facies of the Aquia Greensand analyses are given in table 7. (fig. 13) and the other aquifers of Eocene age (fig. 14) Hydrochemical facies of the Englishtown and Vin- in Maryland are predominantly bicarbonate. Tables 10 centown Formations of Paleocene age, shown in figure and 11 show the decrease in calcium and magnesium 11 and table 8, are similar to those of the Mount Laurel with the corresponding increase in sodium in the water HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A23 TABLE 6. Analyses of water from the Magothy and Raritan Formations in New Jersey belowsurface)land Calcium(Ca) Potassium(K) Bicarbonate Specificconductance (Na)Sodium Chloride(Cl) Fluoride(F) (NONitrate)} well(ftDepthof (°F)Temperature (micromhosat 180°C)(residueat (HCO») Carbonate Sulfate(SO«) Dateofcollection Dissolvedsolids §»~ 3 (C0)3 Location Totaliron(Fe) Silica(SiO,) IS No.Index WellNo. 25°C) s W a Upper figure in ppm; lower, epm Burlington County: f!2 10 10 3.6 34 0 40 12 0.0 13 97 B9 57 July 3, 1953 6.9 216 145 9.4 0.00 I .60 .82 .44 .09 .56 0 .83 .34 .00 .21 !23 10 14 10 88 0 38 20 .2 5.9 95 B4 86 May 24, 1951 55 7.2 318 203 10 2.0 1.15 .82 .61 .26 1.44 0 .79 .56 .01 .10 8.0 4.4 4.8 1.4 8 0 14 8.0 .0 21 93 Bl 120 May 3, 1951 55 7.1 112 84 12 .03 .40 .36 .21 .04 .13 0 .29 .23 .00 .34 / .26 4.6 3.2 6.3 98 0 15 1.2 .1 .6 Mt. Holly-- --- 96 B6 385 May 24, 1951 58 7.9 190 113 9.8 .68 \ 1.30 .38 .14 .16 1.61 0 .31 .03 .01 .01 / 3.6 1.5 2.8 .5 3 0 14 3.2 .0 .8 Stevens Station.. ... 94 B2 150 May 3,1951 55 5.6 49.1 41 12 .71 I .18 .12 .12 .01 .05 0 .29 .10 .00 .01 Camden County: (27 6.1 6.2 8.0 98 0 29 1.6 .2 .6 Haddon Heights. _ . . 67 C2 267 Dec. 23,1949 7.4 228 131 9.6 .64 \ 1.35 .50 .27 .21 1.61 0 .60 .05 .01 .01 f!9 4.2 11 6.6 87 0 20 1.6 .3 .5 56 C3 318 ..-do . 7.5 186 109 8.8 .16 I .95 .35 .48 .17 1.43 0 .42 .05 .02 .01 Gloucester County: f 7.8 5.0 54 2.9 5 0 12 96 .0 6.2 34 G3 105 Aug. 20,1951 56 5.8 373 208 10 .15 I .39 .41 2.35 .07 .08 0 .25 2.71 .00 .10 f 3.0 1.0 18 4.6 292 0 6.2 19 1.6 .7 20 01 630 May 7,1951 65 8.1. 515 315 12 .11 I .15 .08 5.13 .12 4.79 0 .13 .54 .08 .01 / 9.2 2.4 8.1 323 0 6.5 140 1.4 .8 Mullica Hill...... 19 G2 263 Dec. 21,1950 58 8.2 967 538 9.7 1.4 196 Mercer County: I .46 .20 .52 .21 5.29 0 .14 .95 .07 .01 4.5 / 1.6 .8 2.7 .9 0 0 11 2.5 .0 .1 48 M2 85 Sept. 26, 1949 54 53.2 27 7.7 .28 1 .08 .07 .12 .02 .00 0 .23 .07 .00 .00 5.4 f 1.8 .7 2.5 .9 5 0 2.0 2.8 .0 7.2 Hamilton Square. . . 49 M4 228 May 4,1950 34.3 28 6.5 .15 I .09 .06 .11 .02 .08 0 .04 .08 .00 .12 f 2.2 1.2 2.3 1.0 8 0 6.2 2.4 .1 .1 45 Ml 205 Sept. 26, 1949 5.6 38.3 27 9.3 4.1 1 .11 .10 .10 .03 .13 0 .13 .07 .01 .00 Middlesex County: / 2.9 1.5 2.8 .4 12 0 1.4 6.0 .1 Browntown. .-.. 53 Mx3 Apr. 18,1933 27 2.0 34 I .14 .12 .12 .01 .20 0 .03 .17 .00 / 6.2 3.3 3.0 5.1 30 0 1.3 4.2 .4 11 Do - 54 Mx4 117 June 6, 1941 50 1.1 106.9 I .31 .28 .13 .13 .49 0 .03 .12 .02 .18 r 1.0 .9 1.9 .8 8.1 2.6 .0 .0 Old Bridge...... 52a Mx2 Nov. 13, 1942 4.8 22 7.1 3.2 I .05 .07 .08 .02 .02 "6" .17 .07 .00 .00 f 2.9 .9 5.() 6.1 11 3.0 51 Mxl 260 July 18,1923 38 8.0 4.4 I .14 .07 .5 2 .10 0 .23 .08 Monmouth County: 6.; ! 37 0 15 4.0 90 Mol 1,135 Nov. 13, 1924 66 5.5 8.1 7'., !7 .61 0 .31 .11 / 8.9 2.5 12 0 13 18 .0 .0 91 Mo2 481 Mar. 20, 1948 5.5 115 66 8.2 22 I .44 .21 3 .20 0 .27 .51 .00 .00 Salem County: /12 1.4 116 4.9 129 0 1.8 131 .3 .0 Salem.. .--__ -___.- 5 SI 320 Apr. 26,1956 53 7.6 654 346 5.4 2.1 I .60 .12 5.05 .13 2.11 0 .04 3.69 .02 .00 TABLE 7. Analyses of water from selected Cretaceous formations in New Jersey [Geologic formation: Kmw, Wenonah Formation and Mount Laurel Sand; Krb, Red Bank SandJ "os "os g a i O g O 6 ' § o O 6 25 03^ 6 g sf F "S 03 "o? a S CQ 22 03^ § 0)0 3-0 a om 6 2"35« _ §6 09 Location 1 a -a °o S S I 8c o 2 O £ "3.1 6 a "3 3 1 S^" u~II 1 6 * Is o 1"3 g 53 o Is o 1 "3 « 0 & PH CQ 0 s g H Ss oS 1' i ^'po3 Is OJO "35 B 1 S"0 1 W 5* io t-H 0 Q S 0. CQ 53 E- Upper figure in ppm; lower, epm Burlington County: 121 5.4 3.3 8.4 107 0 4.5 2.2 0.0 0.9 Browns Mills... 5 B17 279 Kmw June 4, 1951 59 7.7 187 109 11 0.30 I 1.05 .44 .14 .21 1.75 .09 .82 .00 .14 [22 5.7 5.3 8.5 111 5.0 2.0 .1 .0 Vincentown... __ 4 B18 150 Kmw June 21, 1951 57 8.1 192 115 13 .28 \ 1.10 .47 .23 .22 1.82 .10 .06 .01 .00 Camden County: [24 2.7 2.4 3.5 86 0 9.0 1.8 .1 .3 Clementon.. .. 14 Cl 280 Kmw Apr. 24, 1951 60 7.9 163 103 15 .11 I 1.19 .22 .10 .09 1.41 .19 .05 .01 .01 Monmouth County: [28 6.1 8. 4 107 0 5.8 .1 .6 Belmar. 9a Mo6 452 Kmw Aug. 8, 1951 54 7.8 210 130 14 .15 I 1.40 .50 21 1.75 ----- .33 .16 .01 .01 [36 2.8 9^0 116 12 5.5 .2 ...0 Eaton town.. _-__ 9 Mo7 Krb Mar. 20, 1947 54 7.4 229 131 10 .47 I 1.80 .23 .39 1.90 .25 .16 .01 .00 Salem County: [23 3.8 9.7 3.0 56 0 40 6.6 .1 .7 Salem...... 10 S6 135 Kmw Dec. 21,1950 48 7.4 217 30 10 2.2 I 1.15 .31 .42 .08 .92 .83 .19 .01 .01 [ 58 12 159 .28 7.7 .3 Do ...... 13 S7 Kmw Sept. 15, 1952 7.9 305 .71 CQ I 2. 87 54 2.61 . OO .01 A24 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county /- 6 Burlington 8, 9, 9a Monmouth 10-13 Salem i*> Camden Bold numbers refer to analyses given in table 7 Stratigraphic units Red Bank Sand Mount Laurel Sand and Wenonah Formation FIGURE 10. Water-analysis diagram for selected Cretaceous formations in New Jersey. County:Salem County: Northumberland County:Henrico County:Hanover County:Ocean Burh'ngtonCounty: Kinsale County:Lancaster QueenCounty:Kingand Sea. County:Monmouth County:Westmoreland ______Ellerson. Quinton..--... Alloway__ FortMonmouth. byAvonthe SmithviUe - Marlton____ Lewisetta______Lively____...... RafaelCourt....San Location Mantoloking.... AsburyPark.... Pemberton .ShackelfordsFork.. BridgeBottoms...... Do - I to to ifr O Cn 1 f o- S S Index No. 00 oo Index No. 1^ Ol a a a a to Ol 5 VI » Ol eo Well No. 2 1 1 1 Cn £ CO 0> g eo 0 B g? £ Well No. Depth of well (ft 1 g g ! 01 ! o g 8 8 8 below land surface) Depth of well (ft 1 00 fe below land surface) H H i § § g CD CD CD CD 5 ? 5 5 Qeologic formation o H H H H O i p» p» Qeologic formation on t> Z Z O O n f ? 3 3 8 a May1946 I 18,May1948- 3 to to ^ « E eo *. £3 5» £3 Date of collection 5° Date of collection 0 § 1 1 all § § 8 8 P i -^ .«. 2 S 8 S Temperature (°F) 5- «. *^ S» £» PH i s s s 00 to 2! CO W ^ ^^ 56 1ZL VI 00 *sl OO ^-J OO PH Specific conductance o> o ^J CO ^ o oo to TO K- d (micromhos at Specific conductance § § i i 25°C) (micromhos at s ^ o 1 § s § S i 8 g 25°C) to to Dissolved solids to i 1 S i g (residue at 180°C) (residue at 180°C) eo 2 1 gg 2 S £ S S £ g 8 8 5a 5 Silica (SiOi) S» to 3 CD OS v4 Silica (SiO2) Ol VI 00 p Total iron (Fe) 8 3 8 to 8 eo . . . P g Cn g VI Total iron (Fe) < -1 * 5 ° 8S o» ol . P- . ? 8* /~*g/~*w^3 s i' too £8 Calcium (Ca) to to ife i^ o Ol ;,: «s s ^ * ^ S 8 8 S o C eo M i-* « ** pi pa Magnesium o § ifc 00 oo to co vi 01 !-*.«*. 00 g^ b* So" (Mg) t i 88 to s^s toogto^^ C o,coo,gocoo (Mg) r -. Sodium (Na) vi to i to to to d tog Ol 8*8° OOOt-»v4l~k tOl-*k tO 5s tO VI P 5 fS J^.. «. 00 1 eo 8 S v] ppm;Upperlower,epmfigurein «) «Q S «jjj*-coeo f Potassium (K) 3 §' . !*. f» |^ VI 1^ Ol a I Potassium (K) CO vi 1 » CD 1- * Ol to . tog toS cog tO VI toco coo Bicarbonate (HCOa) co to too toi j-B r § r 8 j Bicarbonate S cor S 8 1 CO Cn >U § (HC03) V Oa S CD B pi o to o J* o Carbonate i 5" Carbonate g<° (C0») < (COO 8 8 8 8 S to co i co to vi oa Oi vi VI co 00 £ Sulfate (SO<) >tt 00 tO Ol to oj to t os os £1 H-toi * - 01 o 1 Sulfate (SO4) if o> b s04 5~ 8 S K to 00 vq o en co o 01 to . eo . .* ~* i-* 01 co to_ to. eo_ to 8* go- t-'O go. S~ Chloride (Cl) Chloride (Cl) S*8® ^ CD h-» S . r o ;; ; ; g 01 S" 8° o to Fluoride (F) s S*8 M ! ! 1 ! 8 to 2~o~8 1* Fluoride (F) ,_ o Nitrate (NOi) ^ o Nitrate (NO3) to 8- OOl g° 8° 001 O vi ovigo go- g^ g tootooeooeo A26 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county i-io Burlington / / - / 7b Monmouth 18, I8a Ocean 22-2^ Salem Bold numbers refer to analyses given in table 8 Stratigraphic units o Vincentown Formation ° Englishtown Formation CATIONS ANfONS FIGURE 11. Water-analysis diagram for the Englishtown and Vlncentown Formations in New Jersey. goo of 5 w County:Caroline ?& ^1 nty Aru If I fit Denton..._ %s PERwC" «Oi| fs<* o n3§- 2. rf r: S -2 n c 2 2 S o- 5 S ?g. 3* 1 B H) " S 3Y! S: 0 S. § jTg to S 0 H- H- tO £ Index No. 9 H* O *. tO tn tn tn tn Q Q 8 § g fe Car-Dd2 Well No. po- PQ- ooo S "2. g & 00 660 a S" OOt^O *3. \.J *£ TO J^ O. ft .y O O 0 ^Cngu3 gi CO^gg Depth of well (ft **a. j» 2 g i i i s § i below land surface) g H H H H H H H Hg >- CD tO CO »J *. CO to_to - H- - to_to _n- - to - ro .co H-_H- gogoogengeng g gen Chloride (Cl) ^. ; ; H> ~ 3.2 001 oo i i oentocoQ*>Qcao J- *.O*.OtOOtOi I OO OO5 Fluoride (F) 8 i- S i i 53 K K H- o > ooooooocoo*.gtoo« ox Nitrate (NOs) to I? EXPLANATION Index numbers listed by county /, 2 Richmond 3 Hanover 4. 5 Henrico 6, 7 King and Queen 8, 9 Westmoreland 10-15 Northumberland 16-18 Lancaster 19-21 Mathews 22 James City Bold numbers refer to analyses given in table 9 Stratigraphic units Chickahominy Formation A Nanjemoy Formation Aquia Formation o Eocene formations, undifferentiated ANIONS FIGURE 12. Water-analysis diagram for the Eocene formations in Virginia. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A29 EXPLANATION Index numbers listed by county Anne Arundel Prince Georges Calvert Charles St. Marys Kent Queen Annes 50- 52 Talbot 53 Dorchester Bold numbers refer to analyses given in table 10 CATIONS ANIONS FIGURE 13. Water-analysis diagram for the Aquia Greensand of Eocene age in Maryland. A30 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county / Prince Georges 2-7 Calvert 8-l9a St. Marys 20 Caroline 21-23 Talbot 24-26 Dorchester 27 Somerset Bold numbers refer to analyses given in table 11 Stratigraphic units * Piney Point Formation o Nanjemoy and Piney Point Formations Nanjemoy Formation A Aquia Greensand FIGURE 14. Water-analysis diagram for selected Eocene formations in Maryland. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A31 from the piezometric high. These aquifers provide an water of the bicarbonate-chloride-sulfate anion facies excellent example of natural softening of water by ion and the calcium-sodium and sodium-calcium cation fa exchange. cies (fig. 17). The low dissolved-solids content of the MIOCENE FORMATIONS water is shown in table 14. As would be expected from the abundance of calcar The hydrochemical facies of the Cohansey Sand in eous material in the Miocene sediments in Virginia, the New Jersey are shown in figure 18. The chloride-sul- water is primarily of the calcium bicarbonate character fate facies is present to a much greater degree in this (fig. 15). For some areas the sodium content has in formation than in any other group of formations of the creased owing to ion exchange. Selective chemical Coastal Plain. The sodium-calcium, the chloride-sul- analyses of water are given in table 12. fate, and the chloride-sulfate-bicarbonate facies are The diversity of the chemical character of water from dominant in the Cohansey Sand. the Miocene formations of Maryland is shown in figure The primary difference between the water from the 16 and in table 13. These analyses are from the Eastern Cohansey Sand and the water from the Kirkwood For Shore, where the recharge and discharge of the water mation, as shown in table 15, is a decrease in the chloride in these shallow aquifers is of a local nature. Slight and sulfate content in the Kirkwood Formation that changes in the hydrologic environment cause pro permits the development of the bicarbonate-chloride nounced changes in the chemical character. Some of facies. The dissolved-solids content of water from the the samples show the effect of nearby salt-water bodies. Kirkwood is among the lowest for any formation in The Kirkwood Formation of New Jersey contains the Coastal Plain. TABLE 12. Analyses of water from the Miocene formations in Virginia [Geologic formation: Tsm, St. Marys Formation, Ty, Yorktown Formation; Und, Miocene formations undiflerentiated] "*« 8 "o? /03 6 8 O 1 O S o> 6 O g sf § F tits fc 03^ GO g. f| ^"* g5! 03 S3 w H rj ^3 3 w Ik! go 0 o> g ^5 O) -e d """Si ^o 5 "S "3 11 8* S 6 "ST* 3"3 O a 1 II03-^ 3 1 _3 Location *7 « ®§ g O a £ f+ 0 '§? "o 5 fc fe I 65 <§bo J!2 .h 0 s 03 PH « O GO o fc fc M Ok O) s!Ok"3 3 O a '§1|5 M^, ^ OX, 1 § 1 5 * 0 O H Ok GO 3 33 H Upper figure in ppm; lower, epm Accomack County: Hallwood..----- 160 129 /25 5.5 8.0 2.1 112 0 0.5 7.8 0.1 0.2 12 47a Ty Apr. 6, 1955 59 8.1 199 31 0.44 \ 1.25 .45 .35 .05 1.84 .00 .01 .22 .01 .00 Do-. . 13 47b 250 Tsm 275 154 (23 9.5 18 7.0 142 0 1.0 17 .1 .7 - do ----- 61 8.3 16 .06 I 1.15 .78 .78 .18 2.33 .00 .02 .48 .00 .01 New Church.. . . 11 259 345 /28 13 64 14 229 0 6.7 66 .2 .9 6a Tsm May 30.1955 59.5 8.0 567 28 .64 I 1.40 1.07 2.78 .36 3.75 .00 .14 1.86 .01 .01 3.6 Pungoteague---- 14 52 210 Tsm 250 (25 11 32 14 218 0 1.6 12 1906 358 45 .1 \ 1.25 .90 1.39 .36 3.58 .00 .03 .34 __ .06 0 4.0 93 .7 .8 Wachapreague. . 9 56 385 Und 8.1 482 482 14 .14 (5.5 3.8 180 346 Sept. 7,1948 61 I .27 .31 7.83 5.67 .00 .08 2.62 .04 .01 15 Onancock---. ... 10 42 210 7.9 203 124 8.5 34 168 0 6.5 .1 2.9 Und Sept. 4,1948 290 24 .07 1 1.20 .70 1.48 2.76 .00 .14 .42 .01 .05 Elizabeth City County: Hampton...... 22 7c 178 Ty 7 9 158 21 804 625 0 119 950 .6 1.6 Nov. 5,1944 14 .09 I 2.89 1.73 34.97 10.25 .00 2.48 26.79 .03 .03 54 .1 .6 Wythe Theater. 21 12 138 Ty 308 126 9.0 61 4.3 163 0 24 Aug. 6, 1940 42 19 I 1.30 .74 2.65 .11 2.67 .00 .50 1.52 .01 .01 James City County: .1 .1 Norge _ ------23 59 88 Ty 108 (32 .8 "."ie" 3.7. 93 0 9.9 3.1 June 15,1946 7.3 11 8.1 I 1.60 .07 .09 1.52 .00 .21 .09 .01 .00 10 5.0 .1 .1 Williamsburg--. 24 52 68 Ty 122 184 .9 3.6 96 0 do ... 7.3 18 .12 I 1.70 .07 .16 1.57 .00 .21 .14 .01 .00 Nansemond County: .0 38 Drivers. ------. 5 40 46 Und (15 9.0 10 3.7 247 0 105 22 Aug. 1, 1939 464 11 7.7 1 6.24 .74 .44 .10 4.05 .00 2.18 .62 .00 .61 New Kent County: 131 0 7.0 2.9 .2 .0 Providence 1 39 110 Und Dec. 31,1943 7 9 144 26 .03 (33 4.4 8.7 Forge. I 1.65 .36 .38 2.15 .00 .15 .08 .01 .00 Northampton County: 2.0 Nassowadox _ . 17 44b 304 Tsm /28 9.2 16 2.5 131 0 3.5 29 .1 Apr. 5, 1955 8.0 316 176 17 .00 I 1.38 .76 .70 .06 2.15 .00 .07 .82 .01 .03 .2 East ville ...... 16 25 165 Und 2PT 126 3.7 11 96 0 1.2 17 .1 Sept. 12, 1948 8.0 145 39 .04 » 1.30 .30 .48 1.57 .00 .03 .48 .01 .03 18 .2 .6 Oyster--_-...__. 19 81 182 7 ^ (29 10 16 144 0 .8 Ty Mar. 5,1946 177 32 .04 I 1.45 .82 .70 2.36 .00 .02 .51 .01 .01 Cape Charles .... 20 204 74 (41 7.0 28 2.1 120 0 24 54 .0 .2 Ty Sept. 27, 1955 ------7.9 402 230 18 .34 I 2.05 .58 1.22 .05 2.97 .00 .50 1.52 .00 .00 Norfolk County: .0 Great Bridge _ - 4 59 ...... Und (68 4.9 41 2.6 243 0 5.0 54 .6 Aug. 28, 1939 62 325 27 .67 I 3.39 .40 1.78 .07 3.98 .00 .10 1.52 .03 .00 A32 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county / New Kent 2,3 Richmond 4 Norfolk 5 Nansemond 6 York 7 Princess Anne 8-/4 Accomack 15-20 Northampton 21, 22 *Elizabeth City 23, 2*> James City 25-27 Mathews Bold numbers refer to analyses given in table 12 Stratigraphic units A Yorktown Formation St. Marys Formation o Miocene formations, undifferentiated Now a part of independent city of Hampton FIGURE 15. Water-analysis diagram for the Miocene formations in Virginia. HYDROCHEMICAL FACIE S, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A33 EXPLANATION Index numbers listed by county /-4 Caroline 5 Talbot 6, 6a Dorchester 7-l2a Wicomico 13-16 Somerset 17-25 Worcester .26 Queen Annes Bold numbers refer to analyses given in table 13 Stratigraphic units Yorktown Formation and Cohansey Sand St. Marys and Choptank Formations o Choptank Formation A Calvert Formation FIGURE 16. Water-analysis diagram for the Miocene formations in Maryland. A34 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county 2, 3 Burlington 4 Salem 5-/5a Atlantic 16, 17 Cape May Bold numbers refer to analyses given in table 14 ANIONS FIGURE 17. Water-analysis diagram for the Kirkwood Formation in New Jersey. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A35 TABLE 13. Analyses of water from the Miocene formations in Maryland (Geologic formation: Tck, Cboptank Formation; Tsm, St. Marys Formation; Tcv, Calvert Formation; Ty, Yorktown Formation; Teh, Cohansey Sand] g belowlandsurface) conductanceSpecific Calcium(Ca) Sodium(Na) Bicarbonate Chloride(CD Fluoride(F) Geologicformation Temperature(°F) (micromhosat (residue180°C)at )(HC03 Carbonate Sulfate(SCM )(NONitrate3 Depth(ftofwell Dateofcollection Dissolvedsolids (CO,) Location (Fe)Totaliron Silica(SiO)2 WellNo. s~ 0 IndexNo. 25°C) Pi ao. Upper figure in ppm; lower, epm Caroline County: f28 17 19 9.4 224 0 5.2 0.6 0.5 0.9 Choptank______3 Car-Fb24 150 Tck Mar. 8,1955 57 8.0 344 244 62 0.17 \ 1.40 1.40 .83 .24 3.67 .00 .11 .02 .03 .02 f 5.2 1.0 5.2 2.6 .4 0 18 4.9 .3 11 Williston... ______2 Car-Ecl4 165 Tck do...... 58 4.6 94.4 65 14 .03 I .26 .08 .23 .07 .01 .00 .38 .14 .02 .18 Dorchester County: {-,-: 1 1 300 14 13 7.0 .8 6 Dor-cf8 189 Tsm-Tck Feb. 19,1954 55 8.4 530 .05 34 4.92 .47 .27 .20 .01 / 9.0 6.2 438 14 804 8 163 170 1.0 .5 6a Dor-Dh7 305 Tcv Dec. 9, 1952 8.5 2,030 1,270 55 3.0 \ .45 .51 18.05 .36 13.19 .27 3.39 4.79 .05 .01 Queen Annes County: f 5.7 2.8 7.5 1.4 20 .6 8.9 .1 18 26 Qa-Cf5 50 Tck Sept. 29, 1954 6.9 87 76 18 .04 \ .28 .23 .33 .04 .33 .01 .25 .01 .29 Somerset County: f31 31 1,260 45 1,200 0 62 1,360 .7 .7 13 Som-Ec33 362 Tck Dec. 8, 1952 7.6 5,780 3,550 58 .17 \ 1.55 2.55 54.79 1.15 19.67 .00 1.29 38.36 .04 .01 Wicomico County: (23 4.7 35 4.7 171 0 1.0 9.5 .0 .3 Fruitland...... 9 Wie-De30 255 Ty-Tch Jan. 10,1951 7.2 302 186 21 8.3 \ 1.15 .39 1.52 .12 2.80 .00 .02 .27 .00 .01 f!2 4.6 245 12 444 0 24 135 1.0 1.2 Mardela Spring.. .. 12 Wic-Bdll 315 Tck Nov. 4,1952 8.0 1,160 734 54 .16 t .60 .38 10.65 .31 7.28 .00 .50 3.81 .05 .02 f 4.2 2.3 8.8 1.0 25 0 9.0 7.4 .1 .3 7 Wie-Df25 86 Ty-Tch Sept. 15, 1950 6.3 90.3 88 39 .19 t -21 .19 .38 .03 .41 .00 .19 .21 .01 .01 f 1.9 1.1 5.0 1.6 8 ' 0 11 3.2 .1 .0 Do-.....-. 12a Wic-Ce21 130 Ty-Tch Mar. 4,1948 5.3 51.3 52 23 3.6 i .10 .09 .22 .04 .13 .00 .23 .09 .01 .00 / 3.2 1.2 7.3 1.0 27 0 3.0 3.5 .3 .2 (>)....- ._.___. g Wic-Bhl4 122 Ty-Tch Ang. 15,1950 7.1 63.8 69 32 5.0 \ .16 .10 .32 .03 .44 .00 .06 .10 .02 .00 Worcester County: f!9 13 26 12 202 0 5.2 10 .0 .7 Girdletree.. _-__---. 22 Wor-Ed8 181 Ty-Tch Nov. 5, 1952 59 7.8 330 208 34 .09 \ .95 1.07 1.13 .31 3.31 .00 .11 .28 .00 .01 |37 16 27 12 226 0 2.0 30 .1 .1 Ocean City...- __ 21 Wor-Bhl 285 Ty-Tch Dec. 12,1951 7.2 434 260 24 2.9 \ 1.85 1.32 1.17 .31 3.70 .00 .04 .85 .01 .00 /29 14 36 10 229 .0 20 .1 .7 Do...... 25 Wor-Bh8 185 Ty-Tch Dec. 17,1951 7.8 413 260 28 1.3 I 1.45 1.15 1.57 .26 3.75 .00 .00 .56 .01 .01 /22 13 25 4.3 138 0 15 35 1.2 .7 23 Wor-Fb» 104 Ty-Tch Nov. 4,1952 59 7.5 339 206 29 6.0 t 1.10 1.07 1.09 .11 2.26 .00 .31 .99 .06 .01 { K* 3 1 123 0 1.2 12 1.2 (>).- 15 Wor-Ce2 210 Ty-Tch Aug. 31,1953 6.8 241 2.4 2.02 .00 .03 .34 .02 ' See Rasmussen and others (1957b, pi. 8). TABLE 14. Analyses of water from the Kirkwood Formation m New Jersey "o? "o? g O I 0 O 0 § fa a fl 1 6 £ 3 ~~* p^3 oo g Atlantic County: /0.16 8.2 0.8 18 2.8 65 0 12 3.4 0.1 0.5 Atlantic City. -... 15 Al 810 Apr. 17, 1956 66 7.8 140 115 34 1 .01 .41 .07 .78 .08 1.07 0 .25 .1 .01 .01 RR An f 5.0 1.6 3.9 7.2 0 9.4 6.0 15a A2 443 Aug. 18, 1825 2.0 i .25 .13 / .12 0 .20 .17 Burlington County: f .8 .9 2.9 2.2 1 0 10 3.1 .0 .1 3 B5 350 Aug. 14, 1951 56 4.7 48.8 49 26 .10 i .04 .07 .13 .06 .02 0 .20 .09 .00 .00 f 1.0 .8 2.5 2.0 2 0 7.0 3.6 .0 .2 New Gretaa.-- - 2 B7 232 do- 56 4.7 47.1 54 32 .32 \ .05 .07 .11 .05 .03 0 .15 .10 .00 .00 Cape May County: / 11 3.1 29 97 0 12 8.0 .8 17 CMS ------May 27, 1952 ------7.5 245 - 27 .11 \ .55 .26 1. 26 1.59 0 .25 .23 .01 f!28 0 23 30 1.0 Stone Harbor 16 CM6 866 Sept. 1, 1955 7.9 337 .20 69 X 2.10 0 .48 .85 .02 A36 HYDROLOGY OF AQUIFER SYSTEMS EXPLANATION Index numbers listed by county 1-4 Gloucester 5-26 Atlantic 27 Camden 28-32 Cape May 33,34 Salem 35-43 Burlington 44 Cumberland Bold numbers refer to analyses given in table 15 40 20 Cl ANFONS FIGURE 18. Water-analysis diagram for the Cohansey Sand in New Jersey. HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A37 TABLE 15. Analyses of water from the Cohansey Sand in New Jersey belowlandsurface) Specificconductance Calcium(Ca) Sodium(Na) (K)Potassium Bicarbonate Sulfate)(SOt Chloride(Cl) Fluoride(F) Depthofwell(ft (micromhosat (residue180°C)at Magnesium (HCOs) Carbonate Nitrate(NO)8 ofDatecollection Dissolvedsolids (Mg) (C0)3 Location Totaliron(Fe) a Silica(SiO)2 IndexNo. WellNo. 25°C) a0. Upper figure in ppm; lower, epm Atlantic County: 200 / 1.2 0.7 3.3 1.2 0 12 5.0 0 Atlantic City 16 A4 Sept. 5,1933 43 16 1.07 I .06 .06 .14 .03 0 .25 .14 .00 6 0 1 10 5.5 .1 Do 21 A5 225 Aug. 30, 1955 63 4.6 53.5 1.3 12 26 .02 .21 .16 .01 19 f 2.0 2.9 9.0 1.0 2.0 5.4 13 15 A6 100 Sept. 6,1933 54 6.2 .02 \ .10 .24 .39 .03 .03 .11 .37 .24 6 7 6 2.4 10 1.3 Somers Point. . 20 A3 Sept. 3,1953 58 5.6 55.7 .03 29 .10 .05 .28 .02 Burlington County: .0 3.2 1.9 1.9 38 BIO 80 May 2, 1951 59 6.9 46.3 44 6.0 .17 f 5.2 .0 5.0 .3 10 Lebanon State i .27 .00 .22 .08 .16 oooooooooojooooooooooooooooooooooooo .00 .09 .10 .03 B12 54 .7 1.8 .3 7 .0 2.9 .0 .1 37 80 Aug. 8, 1951 6.7 16.2 13 4.1 .32 { :l .06 .08 .01 .12 .0 .08 .00 .01 / 1.3 1.9 2.4 .7 3 4.5 8.2 .0 .3 43 B8 31 Aug. 14,1951 56 5.0 79.1 26 4.3 .12 \ .07 .16 .10 .02 .04 .09 .23 .00 .01 / 1.9 1.1 2.2 .6 2 8.5 4.6 .0 .3 35 Bll 40 Aug. 8, 1951 68 5.2 42.6 25 3.7 .59 \ .10 .09 .10 .02 .03 .18 .13 .00 .01 Cape May County: 128 3.2 20 1.4 Cape May . _ .- 29 CM2 330 Aug. 31, 1955 67 7.2 277 .94 83 2.10 .07 .56 .02 f 24 17 81 12 146 23 139 .2 1.0 North Wildwood. 32 CMS 310 Oct. 16,1952 59 7.4 718 412 37 1.1 I 1.20 1.40 3.52 .31 2.39 .48 3.92 .01 .02 84 7.0 12 1.0 Nummytown. . _ 32a CM1 Sept. 1, 1954 59.5 7.2 182 .20 48 1.38 .15 .34 .02 Cumberland County: / 6.6 3.9 1.5 .7 35 3.3 2.5 .0 1.2 Seabrook-- ___ . 44 Cul 30 May 9,1950 7.1 64 39 2.0 5.2 \ .33 .32 .07 .02 .57 .07 .07 .00 .00 Gloucester County: f 4.6 4.0 21 6.2 7 12 18 .01 50 1 O4 100 Apr. 23,1951 56 5.2 174 121 7.9 .02 i .23 .33 .91 .17 .11 .25 .51 .01 .81 f 1.2 .8 2.7 .4 5 1.0 4.2 .0 5.0 Newfield _ ___ 4 07 147 do 55 6.4 33.6 25 5.5 .01 ( .06 .07 .12 .01 .08 .02 .12 .00 .09 / 3.6 5.1 9.8 2.7 4 1.0 13 .1 41 Williams town ..... 2 05 95 -do. .-.. 4.9 141 98 7.7 .03 \ .18 .42 .43 .07 .07 .02 .37 .01 .66 f 2.6 3.1 6.2 1.5 1 .8 5.4 .0 32 Do _-_. 3 O6 130 .... .do .... 55 4.8 89.2 66 8.2 .03 i .13 .26 .27 .04 .02 .02 .15 .00 .51 Salem County: / 5.6 5.4 8.1 3.6 1 5.5 13 .0 44 Elmer__.. __ ..-. 33 82 63 Mar. 15, 1951 4.7 140 105 8.2 .08 ( .28 .44 .35 .09 .02 .12 .37 .00 .70 Parvin State f 2.3 .4 7.4 5.2 11 19 3.0 .2 1.2 Park ...... 34 S3 105 Apr. 27,1956 51 6.0 40.3 61 22 L, I .12 .03 .24 .19 .18 .40 .09 .01 .00 SPATIAL DISTRIBUTION AND ORIGIN OP abundant soluble minerals, we would expect the water HYDROCHEMICAL FACIES to have higher dissolved-solids content closer to the CONCENTRATION OF DISSOLVED SOLIDS recharge area than it would have in an area of coarser sediments containing less soluble material. The primary controls on the dissolved-solids content In addition, the dissolved-solids content of water in of ground water are the chemical character of the water any area increases when water from a different source, as it enters the zone of saturation; the distribution, containing more dissolved ions, is introduced either by solubility, and adsorption capacity of the minerals in sea-water intrusion or by seepage of deeper brines. the deposits; the porosity and permeability of rocks; The effects of these controls can be seen on plate 16", and the flow path of the water. which shows the distribution of the dissolved-solids On the basis of the assumptions that chemical equi calculated from the determined constituents, in equiva librium has not been attained between the water and lents per million. For example, ground water in the the minerals and that an excess of soluble material is near-surface formations and in the recharge areas has available, the dissolved-solids content of the water in a low dissolved-solids content because of the shorter creases and the chemical system tends to move closer to travel path of the water in the aquifers and the prior equilibrium as the flow path lengthens. A constant leaching of soluble material. In southern Maryland volume of water and a decrease in grain size of soluble (section F-F') the dissolved-solids content of the water material will result in a higher dissolved-solids content gradually increases as the water in the Cretaceous sedi along a particular flow path. An increase in concentra ments moves southeastward from the area of recharge. tion due to smaller grain size results from two different Between the recharge and discharge areas of New effects: (1) the smaller grains of any soluble material Jersey (fig. 2, 3), the dissolved-solids content of the will go into solution more readily than coarse grai is of water generally is much lower than that in Maryland the same material, and (2) the smaller grain size causes and Delaware. This probably reflects a smaller amount a decrease in permeability that requires a longer resi of soluble material and a shorter travel path. The dence time to traverse the same flow distance. There lithologic fence diagram (pi. 1A) shows less fine fore, in an area of fine-grained material containing grained material in New Jersey than in the area to the A38 HYDROLOGY OF AQUIFER SYSTEMS south. The presence of coarser material, which may The New Jersey section of the Coastal Plain shows have higher permeability, the shallow position of the less sodium facies than the rest of the Coastal Plain. bedrock that causes a shorter flow path, and the possi However, this does not necessarily imply that the geol bility of smaller amounts of soluble material will result ogy and hydrology of New Jersey is significantly dif in leaching of the sediments more rapidly than in the ferent but rather that all of New Jersey is much closer areas to the south where the sediments are finer grained to the Fall Zone than is the wider part of the Coastal and thicker. Plain in Maryland, Delaware, and Virginia. That is, The head in the Miocene formations in New Jersey if more of the Coastal Plain were emergent in the New is higher than the head in Cretaceous sediments, and Jersey area and was at greater depth and greater dis virtually no upward leakage occurs. In Delaware and tance from the Fall Zone, the sodium facies no doubt in Maryland the head in Cretaceous formations is gen would be more widespread. As it is, the sodium facies erally higher than in the overlying Tertiary sediments. exists only in the Magothy and Raritan Formations and The lower head downgradient in the Tertiary sedi in the Miocene sediments at the tip of Cape May (D'- ments causes the water entering the Cretaceous sedi E'}. ments in the recharge area of the outcrop to move There are two explanations for the presence of the laterally and discharge vertically upward through the sodium facies in Virginia and Maryland: (1) salt water, overlying Tertiary of the Eastern Shore. This circula in which sodium is the dominant cation, underlies the tion pattern provides a mechanism in which the deeper area and (2) ion exchange occurs between calcium in water containing more dissolved solids can move up the ground water and sodium on the clays. This ex ward to cause the dissolved-solids content in the over change occurs as the water moves through the exchange lying sediments to be higher than it would be if the pri material, thereby creating the sodium facies. Plate ID mary movement of the water were downward. shows an outstanding example of ion exchange in south In Virginia (sections /-/' and /-/') the Cretaceous ern Maryland (F-F' and G-G'}. As the water enters sediments are recharged almost entirely by water that the recharge area, the gradual change occurs from the has percolated downward through the Miocene beds. calcium-magnesium facies through the calcium-sodium Although the Miocene sediments are thin in parts of facies and the sodium-calcium facies to the final sodium Virginia, the water has a high dissolved-solids content facies. This pronounced change not only reflects a because the sediments contain an abundance of soluble change in the composition of the ion-exchange minerals material. but also reflects the effect of the flow path on the chem Water from the shallow Cretaceous sediments in ical character of ground water. Thus, the lithology and Virginia has a higher dissolved-solids content than mineralogy determine the type of facies that can pos water from the Cretaceous sediments in Maryland and sibly exist, and the ground-water flow pattern, which New Jersey because of solution of material from the results from the head distribution between the recharge Miocene formations overlying the recharge area of the and discharge areas, determines the distribution of the Cretaceous formations. The water from the deeper facies. In other words, the geology controls the type of formations in Virginia and Maryland has a higher dis facies, and the hydrology controls the distribution. solved-solids content owing to the greater amount of In Maryland, the calcium-magnesium facies occurs in salt water, as shown on plate IE. the Cretaceous sediments near the north-central part of southern Maryland (F-F' and G-G'}. This facies is CATION FACIES approximately coextensive with the recharge area The distribution of the cation hydrochemical facies underlying the plateau of southern Maryland. As the in the Coastal Plain sediments is shown on plate ID. water enters through the Miocene beds containing cal The calcium-magnesium facies is in the shallow forma careous clays, the calcium-magnesium facies is formed. tions near the areas of recharge. This is the most re The water continues its downward migration and lateral stricted facies in the Coastal Plain and occurs in south movement, and the exchangeable materials of the ern Maryland, part of New Jersey, and southern Vir Eocene and Cretaceous formations convert the calcium- ginia. The calcium-sodium facies also occurs in the up- magnesium facies through the intermediate facies to the gradient position and in the shallow formations. The sodium facies. sodium-calcium facies occurs downgradient and gener The calcium-magnesium facies generally is absent in ally in deeped formations. The sodium-potassium the Cretaceous sediments of Virginia. It may be that facies (referred to hereafter as the sodium facies as the water enters the recharge areas of the Cretaceous because of the small amount of potassium) occurs far formation near the Fall Zone the normal process of ion ther downgradient and in the deepest formations. exchange converts the calcium-magnesium facies to the HYDROCHEMICAL FACIES, GROUND-WATER FLOW, ATLANTIC COASTAL PLAIN A39 sodium facies in a shorter distance than in Maryland. moves downgradient. The higher chloride content Another possible explanation is that there are more near the surface along the coast represents part of the sodium ions from sea water near the Fall Zone (/-/') body of salt water that extends from the deeper sedi in Virginia than near the Fall Zone in southern Mary ments to the present ocean. land. Plate IE shows more chloride in Virginia than The distribution of the bicarbonate ion in ground in Maryland (6r-6r'), which would tend to support the water of the Coastal Plain is shown on plate IF. The last suggestion. values plotted are the results of bicarbonate determina The calcium-sodium facies is present in the area be tions made in the laboratory. Water's bicarbonate tween Washington and Baltimore (north part of section content is controlled by its pH and temperature, the M-M' ). It owes its existence there not to the ion-ex partial pressure of carbon dioxide, and the minerals change process but to the lack of calcareous sediments, it contacts. The values of pH and bicarbonate content which, if present, would create the calcium-magnesium of water obtained in laboratory measurements are facies in the outcrop area of the Cretaceous formations. known to be different from the values of these properties of the water in the aquifer, and laboratory determina ANION FACIES tions cannot be used in detailed studies. However The occurrence and distribution of the anion facies analytical error probably does not detract from the are determined by the relative concentration of bicar validity of the regional relationships shown on plate 1, bonate, chloride, and sulfate ions. In most of the FandG. water to a depth of about 1,000 feet, the bicarbonate In the shallow formations and in the areas of re ion makes up more than 50 percent of the total anions, charge, the bicarbonate content is low. As the water and accounts for the existence of the bicarbonate facies moves down through the calcareous sediments of the and the bicarbonate-chloride-sulfate facies. A few Miocene series and through some of the Eocene beds, areas exist in which the chloride and the sulfate ions, as the bicarbonate content increases. This relation is computed on a percentage basis, are the dominant illustrated for southern Maryland in section F-F', anions. The distribution of the anion facies was where, near Silver Spring, the bicarbonate content is studied by construction of fence diagrams showing the less than 100 ppm because the water enters the recharge chloride- and bicarbonate-ion contents, in parts per area of the Cretaceous and Eocene sediments without million, and percentage of the bicarbonate plus car passing through the Miocene beds. Farther downdip, bonate ions. The concentration of the sulfate content the water enters the underlying formations through the was not plotted because of its low values and its rather Miocene beds, and the bicarbonate content has increased. uniform distribution. Also, as illustrated (pi. IF, section G-G'}, the bicar Plate IE is a fence diagram showing the concentra bonate content has increased to more than 100 ppm in tion of chloride ions in ground water in the uppermost the discharge area, where the Miocene beds crop out. 1,000 feet of the Coastal Plain sediments. Much of the In Virginia (section /-/' and others to the south) water contains less than 5 ppm chloride, and all the where the Cretaceous formations are recharged almost ground water except that associated with the deep salt entirely by water that has passed through the Miocene water (pi. IB) contains less than 25 ppm chloride. The beds, the bicarbonate content is relatively high, more salt water along the eastern part of the Coastal Plain than 200 ppm. The bicarbonate content of water in all is identified by the high chloride content. The chloride formations in New Jersey, except the Magothy and the content shown for most of the Pleistocene sediments is Raritan, is the lowest for most of the rest of the Coastal not necessarily valid. Because the shallow sediments Plain. The Miocene formations in New Jersey con are contaminated by sewage effluent and by industrial tain less calcareous material than the Miocene forma wastes the distribution of chloride is erratic. Part of tions in Virginia and Delaware. The primary source the chloride in the shallow sediments along the coast of calcareous material in Miocene sediments in New may be due to atmospheric precipitation of salts from Jersey is from the beds at the base of the Kirkwood the ocean. Formation. The other source of calcareous material In Maryland and Virginia (sections south of E-E'} is in the Honerstown Sand of Cretaceous age. the chloride content ranges from 0 to 5 ppm in the The area in which water has the highest bicarbonate shallow sediments close to the Fall Zone. The content content is associated with the area in which salt water ranges from 5 to 25 ppm at greater depth and closer exists. This is not merely owing to mixing of the fresh to the coast. This is due to the effect of normal solution water with the salt water, because sea water has a of the minerals and to removal of residual adsorped ions bicarbonate content of only 140 ppm. Foster (1950) as the water enters the high topographic areas and studied the occurrence of bicarbonate-rich ground water A40 HYDROLOGY OF AQUIFER SYSTEMS in the Atlantic and Gulf Coastal Plains by a series of The deep salt water that had been identified in many laboratory experiments in which water percolated parts of the Coastal Plain is shown to be one continuous through lignite, then calcite, and finally an ion- water body. Its position is determined by the relative exchange material. Analyses of the leachate closely head distribution in the fresh water and in the salt resembled those of natural ground water; both had the water. The head distribution is influenced by the topo sodium bicarbonate character. The water cannot attain graphic position of the landniasses, the thickness and equilibrium with the calcareous material because of the the permeability of the Coastal Plain sediments, and the exchange of the calcium ion in solution with the sodium geomorphic development of the Coastal Plain. The ion on the exchangeable material; the result is a contin genesis of the salt water is known to be due to one or uous increase of bicarbonate. more of the following processes: Ketention of ions from Mapping of the hydrochemical facies during the the marine water in which the sediments were depos present study suggests that this process may be more ited ; entrance of salt water after deposition; concentra pronounced in the area containing salt water. The tion of ions through common solution processes; and areas of high-bicarbonate water (pi. IF) are virtually selective concentration, with the clays acting as semi- the same as the areas of high-chloride water (pi. IE) permeable membranes. and water containing a high percentage of sodium (pi. The three-dimensional aspect of hydrochemical facies ID). The correlation of high bicarbonate and high can be illustrated effectively by fence diagrams. The sodium is due in part to the greater solubility of calcar calcium-magnesium facies are in the areas of higher eous material in salt water than in fresh water. The head, and the sodium facies are in areas of lower head. greater solubility and removal of calcium ions permits The sodium facies result from an ion-exchange process the buildup of bicarbonate ions far in excess of the con with sodium-bearing exchange material and from the centration observed for water from limestone areas. presence of salt water. Areal differences of chemical Most water from limestone areas would have bicarbon character of water can occur without a change in the ate concentration ranging from about 150 to 300 ppm. type of aquifer material. The lithology and mineral For this part of the Coastal Plain, many analyses show more than 500 ppm; the highest show 1,200 ppm. To ogy determine the type of facies that can possibly exist, determine if the water containing 1,200 ppm bicar and the ground-water flow pattern determines the dis bonate was saturated with respect to calcite, the analyses tribution of the facies. (Somerset County, Md., Ec-33) were used to calculate The regional flow pattern constructed by use of avail the departure from equilibrium, as described previously able head data in the outcrop areas and along the salt (Back, 1960). The amount of bicarbonate that would water interface was substantiated by mapping the be required for the water to be in equilibrium with hydrochemical data. The chemical and hydrologic data calcite is about 4,000 ppm, as compared with the provide a convincing example of the outcrop area of an analyzed value of 1,200 ppm. Therefore, even with artesian aquifer functioning equally well as either a this high bicarbonate content the water is still capable discharge or recharge area. Depending on the head, of dissolving more calcareous material. distribution of the water can move updip as readily as SUMMARY AND CONCLUSIONS it can move downdip. The existence of hydrochemical facies indicates a This study demonstrates a method by which the geo- close relationship between the hydrologic processes and hydrologic significance of the chemical character of the aquifer material. More regional studies of the field water may be emphasized. The chemistry of ground relationships among ground-water movement, mineral water is controlled entirely by the lithology of the deposits through which the water flows and by the ogy of the geologic formations, and the chemical char orientation of the flow path within the geologic frame acter of ground water are needed. Such studies could work. 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