WATER INFORMATION BULLETIN NO. 16
A RECONNAISSANCE Of THE WATER RESOURCES
IN THE PORTNEUF RIVER BASIN. IDAHO
by
R.F. Norvitrh and A.l. larson
United States Geological Survey
Prepared by the United States Geological Survey
in Cooperation with
Idaho Department of Reclamation
Published by
Idaho Department of Reclamation
R. Keith Higginson
State Reclamation Engineer
June 1970 CONTENTS
Page Abstract ...... 1 Introduction ...... 2 Purpose ami sc.:ope ...... 2 Previous st udies ...... 2 Acknowledgments ...... 4 Numbering system ...... 4 Use of metric units ...... 4 Physiography ...... 6 Topography ami landforms ...... 6 Drainage ...... 7 Upper valley ...... 7 Lower valley ...... 8 Clin1a te ...... 8 Ccologlc units anti their water hcanng charac teristics ...... II Wate r resources ...... 16 Sources ...... 16 Ground water ...... 18 Water level lluctualions ...... 19 Well anti aquifer chamctcnstks ...... 23 Springs ...... 24 Surface water ...... 31 Floods ...... ·...... 39 Quality of wate r ...... 40
Ust! of lA a ter ...... 45 Ground- wutcr irrigation ...... 45 Above Topaz ...... 45 Below Topaz ...... 4 7 Surface water tniga lion ...... 4 7 M unjcipal and indus trial supplies ...... 48
JI CONTENTS- continued
Page Interrelation of surface and ground water and the effects of pumping wells ...... SO Recommendations for future studies ...... 5 l Water budget ...... 5 1 Water- table mapping ...... 52 Hydrology of aquifers ...... 53 Irrigation system ...... 53
Geologil; mapping and tlc~p test drilling ...... 54 Special problems ...... 54 Sumn1ary ...... : ...... 54 References citt!d ...... 56
ILLUSTRATIONS
Figure I. Jndcx and topogmphic map of Portneuf River basin ...... In pocket 2. Diagram showing U1e weU - numbering system ...... 5 3. Distribution of predpitation on the Portncul' River basin ...... CJ 4. Graph showing average monthly temperature and precipitulion at McCammon. Grace, and Pocatello ...... 13 5. Map showing the generalized geology of the Portneuf River basin ...... 14
6. Geohydrologic sections of ~htrsh Creek valley and Portneu f Valley ...... I 5 7. Map showing contours on tht.: watt.:r tahlc in fall llJ68 and locations of wells and springs ...... 17 S. Hyurographs of observation wells ...... • ...... 22 9. Map of the stream drainage system. Joc:ation or measuring sites, and selected stream -discharge data ...... 32
III ILLUSTRATIONS continued
Figure Pag~
I 0. Gre~phs '>howing annual monthly mean dischargl!s at selected gaging stations ...... 33 II. Graph showing flow duration curves for selected__ ___ gaging stations ...... 34 12. Graph showing !low- duration curve o f daily now. Portneuf River at Topaz, during irrigation season TABLES Table I. Description and water- bearing characteristics of geologic units ...... 12 2. Characteristics of flowing wells in the vicinity of Arimo ...... 20 3 . Chemical anaJyses of water ...... 2 1 4. Records of wells ...... 25 5. Selected data on municipal water supplies ...... : .. .49 IV A RECONNAISSANCE Of THE WATER RESOURCES IN THE PORTNEUF RIVER BASJN.lDAHO by R. F. Norvit~h and A. L. Lm;on AHSTRACT fhe part or lhL' Portncul' Riv~r bct-.in lksnibed includes The average annual wutcr supply of the basin is estimukd to lw sligh tly more t hun 1.2 mill ion unc fc~:t. Pr~dpitation on the basin contributes about 1.2 million acre f~:et, importatio n or water from the adjucent Bear River basin contributes about 0.014 mi ll ion a<.:rc rc~ t and an unknown amount is l.!ontributcd by undernow from the Bear River basin. The major aquifers in the b The major use nf walcr 1s for irrigution. About 13.500 ucres are irrigateu with ground water. Gross pumpag~ i!> about 30.000 acre- fee_! per irrigation season and Ute average consumptive irngution requirement is about 1.1 acre feet per acre. Thus, annual net pumpage for irrigation is about 14.800 aae- feet There is no evidence to llatc that the aquifers are being ova dev~loped by pumping Roughly 9 1.300 acre· 1\:c t of surl'ac\' v. ater is distributed annually to irrigate about 20.000 acres or land. An apparent los'> in strcamnow l'rom Portncuf River and Marsh Cret·k of o..tbout ~)7 cu hie feet per st'cnnd ( 63.000 acre feet per year) on:urs somewhere between the gJg.i ng !>tut ion:. at Topaz ami McCammon and the gaging ~ t ation at Pocatello which is oul or rhc urea of study. Probahly the Portncuf R1ver is rerchcd above the water table. at least in th~ reach from Inkom to the Portn.:urGup and some distanct' bt:yond. thus facilitating thi~ los~ . Major items on whit:h luture work should roc:us fnr a more l'Oillprehen::..ive wal(;f -rcsoun:c:. cvJiuution of the bu:::.in arc: t l) water budgt.•t. 12) hydrologk mapping, ( 3 l hydrology of aquifer\, (4) irrigation sy-.tcm. C)) geologic mapping. and (6l special problem-. INTRODUCTION This report presents the results of a reconnaissance of the water resources in the part of the Portneuf River basi11 that lies upstream from the Portneuf Gap. The area of study includes about 1.160 square miles. ::md, excl.'pt for a small area in Gem Valley. is bounded by surface-drainage divides in the surrounding llighlands. figure I. Because both the surface and ground- water divides ucross Gem VaHey are somewhat nebulous. the boundary in the valley W<.ts drawn on the hyurologic areas boundary adopted by the Idaho Department of Reclamation. The southeastern boundary of the area Ues along the div1de between the Columbia River basin and the Great Basin. The area, as described above. will subsequently be referred to in this report as "the Portneuf River basin" or "the basin''. Purpose and Scope This hydrologic reconnaissance of the Portneuf River basin was made by the U.S. Geological Survey in cooperation with the Idaho Department of Reclamation. It is part of an overall program to evaluate the water resources in the State so that a11 orderly optimum development of those resources can be attained. The primary purpose of this report is to present and discuss the hydrologic data collected during this reconnaissance. In add1tion, hydrologic problems that have resulted from use or the water resources are pointed out. and the scope required of some future project aimed at describing more fully the water resources of the basin is presented. The work accomplished during this reconnaissance, made in the period J uly 1968 to June 1969, consistetl of ( 1) a partial inventory of water wells in the basin; (2) establishment of new stream- gaging sites and ground water observation wells: (3) geologic and hydrologic mapping: (4) mapping of areas irrigated with ground water: (5) an evaluation of the use of ground and surface water for irngation; (6) an evaluation of the interrelation between surface and ground water; (7) a generahzed appraisal of the chemical quality of the water resources: and (8} an evaluation of the need for and the possible methods that could be used to make a comprehensive quantitative study of the water resources of the basin. Previous Studies No ovt!rall geologic or hydrologic study of the Portneuf' River ba::;in has been mach: although parts of the geology and some facets of the hydrology have been included in reports of other areas. The l!arlil!st geologic mapping wa'> done in the north~rn and 2 northeastern part of the basin by Mansfield (Mansfield and Heroy. I 9::!0; Mansfield. 1929, 1952) who reported on the geography. geology. and mineral resources of the Fort Hall Indian Reservation. Later geologic works consisteJ of local studies that described the geologic forn1ations and strudure of h1ghland areas in the basin. The limits or. and references to. those studies are shown on the generalized geologic map (fig. 5 ). The generalized geology of the entire basin is shown on the State geologic map ( Ro~s and Forrester. 1947). Early hydrologic work in the arc<~ t:onsisted of streamnow measurements made at d ifferent times in the Portneuf River Jnd in Topancc and Pebble Creeks during the period 1910-15. The recon.ls of those measurements and later streamflow measurement~ made through September 1950 are t:ontained m Water-Supply Paper 1317 (U.S. Geological Survey, 1956). Sttbscquent streamflow records are contained in Water- Supply Paper 1737 (U.S. Ge0loeical Survt•y . 19o3) ;mel in an annual series of reports titled ~ Resou rces Daw for Jdaho. Heroy (Mansfield and Heroy, 19'20) briefly described the surface drainage system of the basin in an early study of the water resoun;cs of the rort Hall Indian Reservation. Fragmentary information on the irrigation system in the basin is contained in Water- Supply Paper 657 (Hoyt, 1935) which is an early report on water usc in the Snake River basin. ea111S and otltCJ s ( 193!5) gave bJief geologic a11d llydiOtogfc-d-escriptiom of pat ts o f rh----- Portneuf River basin in a report on the Snake R iver in southeastern Idaho. Plate 19 of that report shows contours on the water table (for 1928- 29) in the upper Portneuf Valley and along Marsh Creek from Virginia northward. Mundorff and others ( 1964. p. 44. 94 ), in descrj bing the hydrology of subareas of the Snake River basin . include est imates of water yield for the parts of the Portneuf River basin above Topaz and above Pocatello. An early reconnaissance study by Twiss (I Q39) of the Marsh Creek valley from Red Rock Pass to about a mile north of McCammon brieny described the geology and grouml water resources in that part of the basin Twiss included a generalized geologic map. a water-table contour map, and a map brieny categorizing water conditions in the valley. Other report!S thai discuss topics related to the geology anc.J water resources of the basin include a geographic study of Marsh Creek valley by Strawn ( 1964). a soil survey of a large part of the basin by Lewis and Peterson ( 1921 ), a preliminary report on tht! Portneuf Marsh Valley Canal Project by Woodward (1956). and a rewnnaissance report of erosion and sedimentation in the basm by Merrell and Onstott ( 1965). l n addition to the above reports. the U.S. Army Corps of Engineers has maJe flood- control project studies ncar Inkom and Lava Hot Springs. Some preliminary unpublished data on the results of that work were available for use in study. 3 Acknowledgments Many farmers in the area oooperated fully in offering information about their irrigation practices and in allowing water- level measurements to bt:! made in their wells. Operators of small businesses also cooperated in providing well data. Municipal officials and employees were helpful in providing infom1ation on town water-supply systems. Officials of the Utah Power and Light Company, Preston, Idaho, and the Idaho Portland Cement Company, Inkom, ldaho, were very helpful in offering data for use in this study. To all of the above, the authors are grateful. Numbering System The numbering system used in Idaho by the U.S. Geological Survey indicates the location of a well or spring in the official rectangular subdivisions of the public lands (fig. 2). The first two segments of the number designate the township and range. The third segment gives the section number and is followed by three letters and a numeral, which indicate, respectively, the quarter section. the 40- acre tract, the 10-acre tract, and the seriaJ number of the well or spring within the tract. Quarter sections are lettered a, b, c, and d in a counterclockwise order from the northeast quarter of each section. Within the quarter sections, 40-acre and 10- acre tracts are lettered in the same manner. Thus well 7S-38E- 13ddb I is in the NW~SE~SEY.! sec. 13. T. 7 S .. R 38 E .. and is the first well visited in that 10 - acre tract. Use of Metric Units ln this report, the units that indicate concentrations of dissolved solids and individual ions determined by chemical analysis and the temperatures of air and water are metric units. This change from reporting in "English units" has been made as a part of a gradual change to the metric system that is underway within the scientific community and is intended to promote greater uniformity in reporting of data. Chemical data for concentrations are reported in milligrams per liter (mg/l) rather than in parts per million, the units used in earlier reports of the U.S. Geological Survey. For concentrations less than 7,000 mg/1, the number reported is about the same as for concentrations in parts per million. Air and water temperatures are reported as degrees Celsius (OC). The following table will help to clarify the relation between degrees Fahrenheit and degrees Celsius. 4 Ffl I a;~ I I I I I I ~ IN IW BliSE lASE L I NJ I E 2E 37E 38E 39E 40E IS ~165 ttl I al 7S I J R. 38 E. SEC T ION 13 I I I I 6 5 4 3 2 I I I I I I I I 7 8 9 10 II 12 ----~---- t--- - ~- ---- I I I I T 16 17 16 15 14 ~/;a~ I I I 7 ~---+---13---+- -- I I S. 19 20 21 22 23 24 ------30 29 28 27 26 25 ~d;pi_ I I I bo I a I I I c r--d-- 31 32 33 34 35 36 : I I c : d . ~ I I 7S-38E-13ddbl FIGURE 2 . - - Diagram showing the well-numbering system. (Using well 7S- 38E-13ddbl) . 5 TEMPERATURE- CONVERSION TABLE For conversion of temperature in degrees Celsius ( o C) to degrees Fahrenheit ( Of). Conversions are based on the equation, °F = 1.8° C + 32. Temperatures in °F are rounded to nearest degree. Underscored equivalent temperatures are exact equivalents. For temperature conversions beyond the lintits of the table, use the equation given, and for converting from ° F to ° C, use ° C = 0.5556 ( ° F - 32). The equations say, in effect. that from the freezing point (0° C, 32 ° F) the temperature rises (or falls) 5 oc for every rise (or fall) of 9 OF. oc Of oc Of oc Op oc Op oc Op oc Op oc Op -20 -4 -10 --14 0 32 10- -50 20- --68 30 -86 -40 104 -19 -2 -9 16 +1 34 11 52 21 70 31 88 41 106 -18 0 -8 18 2 36 12 54 22 72 32 90 42 108 -17 +1 -7 19 3 37 13 55 23 73 33 91 43 109 -16 3 ~ 21 4 39 14 57 24 75 34 93 44 111 ·15- -5 -5 -23 5 41 -15 -59 25 77 35 95 45 113 -14 7 4 25 6 43 16 61 26 79 36 97 46 115- -13 9 -3 27 7 45 17 63 27 81 37 99 47 117 -12 10 -2 28 8 46 18 64 28 82 38 100 48 118 -11 12 -1 30 9 48 19 66 29 84 39 102 49 120 PHYSIOGRAPHY To pography and Landforms Physiographically, the area is in the norttteastemmost extension of the Basin and Range Province of the Intermontane Plateaus (Fenneman, 1931, pl. 1). It is in the Great Basin Section which is characterized by isolated ranges separated by aggraded desert plains. Three north- south trending mountain masses occur in the basin. They arc the Pocatello and Bannock Ranges on the west. the Portneuf Range through the center, and the Chesterfield Range and Soda Spring Hills on the east. The three mountain lineaments delimit two roughly parallel, intermontane vaJJey areas- Marsh Creek valley on the west and Portneuf and Gem Valleys on the east. The two valley areas are connected by a gorge about 18 miles long. cut through the Portneuf Range. The general land- surface altitudes in the upper valley (Portneuf and Gem Valleys) range from about 5.400 to 5,800 feet above mean sea level. whereas the general land- surface altitudes in the lower valley (Marsh Creek valley) range 6 from about 4,500 to 5,000 feet. Extreme altitudes in the basin range from about 4,485 feet on the valley floor in the gap at Portneuf to 9.260 feet urop Bonneville Peak, about 6 miles southeast of Inkom, in the Portneuf Range. The most prominent landform in the upper valley is an extensive basalt (lava) plain that makes up the surface of the southern half of the valley (see fig. 5 for locations). From its leading edge, which extends roughly from the mouth of the Portneuf Gorge to a point midway between Chesterfield and Hatch, the basalt surface slopes generally upward toward probable eruptive sources in the Blackfoot Lava Field, east of Tenmile Pass, and in the vicinity of Alexander Crater. In the area between the ~dge of the basalt plain and the dam of th~ Portneuf Reservoir, the Portneuf Valley noor is chiefly flat and low in relation to the surrounding plain. North of the reservoir. the valley narrows considerably and extends into a topographically rugged upland in the extreme northern part of the basin. Apparently. basalt from the upper valley flowed through the Portneuf Gorge into the lower valley where it forms a low-lying plateau on the east side of Marsh Creek. This plateau extends from about 2 miles north of Arimo northward to the confluence of Marsh Creek and Portneuf River. Beyond the confluence, the basalt forms terraces along the river downstream to Portneuf Gap. Other notable landforms in the lower valley are deeply dissected pediments on both sides extending the full length of the valley, and alluvial terraces lying between the pediments and the flood plain of Marsh Creek, largely upstream from McCammon. Drainage Drainage from the basm JOins the Snake River at American Falls Reservoir and thence joins the Columbia River drainage to the sea The Portneuf River and its largest tributary, Marsh Creek, are the major streams in the study area. The total length of the Portneuf River within the basin boundaries of this study is about 70 miles. The pattern of drainage is shown in figure 9. Upper Valley Only that part of the upper valley north of the basalt plain is drained surficially. lntem1ittent streams flowing out of the mountains along the east and west sides of the basalt plain lose their entire discharge to the ground before they reach the basalt surface. Part of the Jost discharge rmaJJy joins the Portneuf River as ground-water discharge from springs that occur in and about the river flood plain in the west part of the upper valJey where the river flows into the Portneuf Gorge. Similarly, with the possible exception of Topance Creek, streams that flow onto the alluvial flat in the central part of the upper valley, such as Twenty fourmile, Eighteen mile, and King Creeks, lose most, if not all, of their 7 discharge before they reach the river. Some water from Topance Creek is diverted into Portneuf Reservoir and thlLS into Portneuf River. However, water in the other creeks mentioned is either diverted for irrigation or seeps into the subsurface. The river-channel gradient between Portneuf Reservoir and a point about 6 miles downstream is only about 5 feet per mile. The water table is at or near land surface causing marshy tracts of land in that general area. Thus the central part of the upper valley is poorly drained in places. The channel gradien.t steepens appreciably as the river flows through Portneuf Gorge, dropping about 575 feet in the 25 - mile reach (23 feet per mile) between the outlet from the upper valley area and McCammon. Under natural conditions, the river gains water as it flows through the gorge. It receives ground water from seeps and springs (including discharge from hot springs) and the discharge from Pebble, Fish, Dempsey, and Bob Smith Creeks, and a number of smaller tributaries. Lower Valley Marsh Creek flows generally northward from its headquarters area near Red Rock Pass to its confluence with the Portneuf River near Inkom. It flows sluggishly in a valley whose major features were formed during the massive flood of Lake Bonneville waters to the Snake River (Malde, 1968). lts channel meanders over a flood plain that is much larger than could have been formed by the present-day stream. Because the stream gradient is low , about 4.5 feet per mile, and the water table is at or near land surface, marshy areas occur along much of the flood plain. A large part of the discharge of Marsh Creek comes from springs. Probably the only perennial tributaries are North Fork, Birch, and Hawkins Creeks. Because much of the discharge from these creeks is diverted for irrigation during the growing season. most of the late- summer discharge of Marsh Creek is due to springs and irrigation return flow. Flow ill the tributaries that rise in many small canyons in the mountains to the east and west is intermittent and most, if not all, of the flow is lost by seepage into the valley-fill sediments before reaching Marsh Creek. Much of the lost flow, however, reappears as springs and seeps alon_g the Marsh Creek channel and flood plain. The total length of Marsh Creek, exclusive of its north fork, is 52 miles. Near McCammon, the Portneuf River bends sharply northward and flows in a channel on the east side of the low-lying basalt plateau in the lower valley. At its confluence with Marsh Creek near lnkom, the river again beds sharply and flows westward through Portneuf Gap, then northwestward to American Falls Reservoir. Climate Climatic conditions in the basin are variable, largely because of the appreciable topographic relief. Figure 3 shows the. areal distribution of precipitation based on the period 1920-67. Annual average precipitation ranges from less than 15 inches on the valley-floor areas near Downey and Bancroft to as much as 35 inches on some of the higher mountains. 8 "H Po &XPLl\IIATlOS --15-- L tno •C eqvbl Avor49e •nn\.lol fr•e J.p.u:.at.IOf'l lb4.6e petiod 11020 ... 67» lntl."rvol 5 l.nch&a 0 Sn~ eourse frrc:sp1t.auon• stat-lon 1. &t: .. r!lqe proclpic_,atlcn •tatJ.on ouu.n&'fe oaaa.n bou.nct•ry _...__~ .., ••... •Na tad FIGURE 3.-- Distribution of precipitation on the Portneuf River basin, Idaho. 9 Conditions are generally semiarid over much of the valley lowlands and subhumid in the upper benchlands and in the mountains. Humid conditions may exist in some high-altitude forested areas. Because summer precipitation is generally low and afternoon temperatures are high, arid conditions may exist seasonally tn the Jower valley areas. Earlier precipitation maps covering the Portneuf River basin are in gross disagreement with each other. For this reason, additional new data now available from stations in and near the basin were used to construct a new precipitation map. Precipitation data from short-term stations were carefully adjusted by correlation with longer records to obtain estimates for precipitation during the 1920- 67 base period. Precipitation in intermountain basins is highly dependent upon altitude and general topography. For thts reason, precipitation at a given point in the Portneuf River basin is dependent upon the surrounding altitudes as well as the altitude at that point. Therefore, the concept of effective altitude, raw than actual altitude, was used in plotting the effects of altitude on precipitation. This concept was developed by Peck and Grown (Peck, 1962) for use along the Wasatch Front in Utah, and is defmed as the average of the altitude obtained at eight points of the compass a mile and a half from the point. Weather records are sparse in the basin. Early stations now abandoned were maintained at Downey and Chesterfield. Records at these stations were obtained during relatively dry years and do not represent average conditions in these valleys. Monthly and annual averages of precipitation data obtained from Weath.er Bureau records for these stations are as follows: Aver'!*e precipitation (inches) Month Chester£.eld Downey {1894-1920)1 (1895-1902)2 Jan lUCY 1.28 0.84 February 1.06 .45 March 1.33 1.24 April 1.03 1.10 May 1.86 1.27 June 1.28 .42 July .86 .28 Augu-st 1.03 .40 September .83 .36 October 1.07 .98 November 1.00 .68 December 1.14 .78 Annu~ (period of record) 13.77 8.80 Annual (adjusted to 1920- 67 base period) 16.55 12.03 1chesterfield records are partial for years 1894, 1918-22. Averages are computed from available r~cords only. 2Downey records are partial for years 1895-97. Averages are computed from available records only. 10 More recent records of temperature and precipitation were collected for the period 1949- 67 at McCammon. These records are compared on figure 4 with the records at Pocatello and Grace, two stations outside of, but near, the periphery of the basi n. Average monthly temperatures at McCammon are in close agreement with those at Pocatello but are somewhat warmer than those at Grace.' However, the distribution of average monthly precipitation at McCammon is more like that at Grace than at Pocatello. Climatic conditions at Grace are probably similar to those in much of the upper Gem and Portneuf Valleys. Several snow courses are measured within the basin. Their locations are shown in figure 3. Only the Pebble Creek {1945- 61) and Dempsey Creek {1956-69) courses have sufficiently long records to warrant averages at this time. The average of the annual maximum water content of the snow accumulations at those stations for the periods indicated above is 14.6 and 1 1.4 inches, respectively. GEOLOGIC UNITS AND THEIR WATER- BEARING CHARACTERISTICS For the purposes of this study. the geologic formations in the basin are grouped into units of pre- Tertiary, Tertiary, and Quaternary ages. Table I gives a generalized description of the geologic units and their water-bearing characteristics. Figure 5 is a compilation of the generalized geology in the basin and is based on previous mapping done by those authors whose works are referenced in the figure. Where the work of different investigators in adjacent areas did not coin cide. arbitrary geologic-boundary connections have been made. Because field geologic mapping was not a part of this reconnaissance study, aeriaJ photographs were used to extend contacts into areas not covered by available maps. Because no detailed field mapping has been done in Marsh Valley, that part of figure 5 should be considered a~ highJy generalized. However, the occurrence of the geologic units in Marsh Valley was discussed by Strawn ( 1964) and Twiss (1939) and their works were used as guides to complete the map. The geohydrologic sections m figure 6 which illustrate geohydrologic conditions in aquifers underlying major areas of ground-water pumping, were drawn using drillers' logs of wells. The sections indicate the subsurface conditions that may be expected in wells drilled in the general areas traversed by the sections. Tbe thickness of the Quaternary basalt as drawn in section B-B' was partly based on preliminary geophysical work that was done about 5 miles to the south in Gem Valley. The sections are necessarily generalized because of the complete lack of geohydrologic test drilling anywhere in the basin. · 11 Table l. Description and >.·ater-bearing characteristics of geologic units in ~he Portneuf River basin. System Gco logic unit Description WateT-bearing chnrnct~ristics Soil, clay, sill, !land, grnvd, and bouldor•;. Sand, Kravel, and boulder units are the mnjor Includes "ell-sorted llolocenc alluvliJI\\ de source of 'uppl y co irrigation on.J domestic pOsited in nream .;hannels and stream ~veil< in ~Iarsh Cre~l. valley and in nortlH·m floo.lptatns; tal..e <:lays interbedded witn part of Por\ntuf VIi 11 ey. Speci fie capaci tics • older alluvium in subs-urface, alluvial fan• (from r"por't<:d d~cn) of wells ran11e f r om le: Calci\llll carbonate dcposi"t:, Generally light Unl..nown as source of supply. lihere sarur:1te Igneous cxtrusi ve flow roc!. (lava) ;utd cinders. ~'ajor source of SU!>ply to lrrigatlon wells in Basalt is generally medium-dar._ gra} . Cindtors <;outht-rn half of POrtl\euf and northern parr .1rc genornll)• reddish brown. Te:ttural of Gom Val Jcys. Magnitude of )'jeld dep~nds Rnsalt varieties range from tti4SSiVI! 0 ver}' fine grain on locul permeabillty of the fot'111Rtion at ed to vesicular. Fracl:urcd, fissur~d. and indlvidli'Jl "·ell sites. 5p.-clfic c~pacitle• jointed; snows collupsed structure l.n places. of W<-lls ranAe from 11bout ! to 3,000. Conglom~»rate, s:tndstonl', grit, t.>hitc· calcareous litrlc >.nown a,; to wHer-benTinc. cnpnbilitic•, cla}', and volcanic tuff, Soil~ fonnccl on ~ur la:rp,ely because it is diffi.:ult :o di~t'n~ul~h Snlr Lake facc are com:non Jr ''hi tc or llght colored ond fron• older alluvium tn driller5' lqg!l. Also Terti;ay Formation interspersed wi~h gravds of lllrRely local whcrc unH .lS l'enot nted, the we II gene.,. a I 1y orig:i n. Contains boulders as much as 4 to S 1s producing abt> l'rom oldc1 nlluvi1.11.n. A good feet in diameter; matri~ of conglomerate is ~ourc~ of supply at so~e places. ~.>hi tc, rclativ<-1~· soft, loose textuJ"cd, 3nd calcareous. Consolidated sedit:Jentar)' fonnations; composed Fe..- t~·ells are knmm to penetrate bedrod. in of limestone, dolomite, sandstone, quartzit~, bnsin; henct!, littl~ data is nvoilnble. Bedrock, shale, a nd chert. Solution cavi tics in 1 imcstone, i r present Pre-Terl iary un~lfferentiated and when penetrated, ~·i 11 trans11it large qunm i ties of ll'atcr to wells. Secondarr op<'ntngs, such as Fractures, in other bed roc!. format Ions ~cnernlly do not yield water ar high rates. • \~ell rield measured in gpm per foot of "~ter-Jovel drawdC\wrt. E-< (/) H :::> 30 r.tl H :r: u z H McCommon 4:1 ~ u •••.••••••• ;veroge annua l 7.5°C :I: ~ (/) 20 . . ~ Ill •. •• .... __ ••• •• ,...... Pocotet to 68 (J) •• •• // -.., •• ••. Average annual 8 2°C (IJ ~ .. · / ' .. (.!) .· / ·. Ill ·,, ' ,, .... ~ (.!) 0 / '\:'•. (IJ / '\:~ tO 50 0 z / '~ H / ~ z / / " H Ill / \ 0:: / " \ (IJ :::> 0 //'""--Grace \ E-4 32 0:: _,/ Average annual 5 8°C :::::> / ' ' ·. ~ / '·.. E-< (IJ ' . At ~ ~ ---- (IJ (IJ A. E-4 -10 14 :8 ~ E-< McCommon 2.0 Average annual 14.94 1nches (/) ~ u z 1.5 H z annual 14. 21 mches H ...... ~ 5 1.0 H E-< ...... ~ E-< H At .··· H 0.5 ... u . ... .··· ·· ~ \ •• · JAN. FEB. MAR APR. MAY JUNE JULY AUG. SEPT OCT. NOV. DEC FIGURE 4.-- Average monthly temperature and precipitation at McCammon, Grace, and Pocatello, for the period 1949-67 . 13 \.l,.tTCO Sta'ttS Q[PAAf'-'f'"IT Of "'"''" 11\'""UI'IOA PP(PAA:£0 •f G:J ... Trovet't.tne Salt 0 8<)dc-ock. undil!e.r-~nt.i.l ted Cont:.act Ora.J....na,gv---· b.uai·- n bound.s.ry f t.:211 ,_,.,. u o; t.n••• ••• l•t••., D ,..., ••4 '•urt•, tOIIO •'NtC..., "••~~~. Ot:llt '-l•h Cllf •.c:•tt I, HI:;.,.), I'"• FIGURE 5.-- Map of the generalized geology in the Portneuf River basin, Idaho. 14 ;; ;; ~ ~ tl u 0• 0 • • ~ 0 0 0 ...... v ... ~ ~ u ~ 0 :0 0 '0 '0 0 '0 .. ID II ,.., > I w a: ,..,CD :) I c: • .end surface, Ill " ....~...... ~ ID Appro• mote pos.. t~~·~·;,;;; ...... ,...... of water table A luvlum (Ool) Older o11uv1um (? or t Salt Lake Formot•on (Tsl) (;>) ..~ ~ I ct" 4 95o'·~------~------~L------~ 0 I 2MILES VERTICAL EXAGGERAT ON lt 26q DATUM s ME AN SEA LEVEL Geohydrologic section A-A' 5750 B B' 5700' -"0 '0 !! 2? u 0 u C> '0 Ql .o- 5600' 0 "0 ..,. ... 0 .. 0 N .! ..a. a. & lu .., w!. ~ 010 tl ,.., "0.., :0 0 .. ssod .Q 0 .~ 0 0 0 -Q; ID 10 ,.., (\J (\1 I I I w w w 01 CD CD 5400' I") I ,..(fl 530o' .--..-- __., -? ..- 520o' - _.-- ?--- 510d Older olluv•um (?)or Soli Lake Formation (Tsl) (?) 1- ...J 5000 Pre-Tert1ory rocks :::;) und1fferenlloled (pT) 4950' ~ 0 I 2MILES VERTI CAL EXAGGERATION x 26 4 DATUM IS MEAN SEA LEVEL Geohydrologic section B-B 1 .., :0 .. "'u "0 .., _ 0 Ql - tl ~ .. '0 0 '0 0 ... ' 4500' - 0 I 2MLES VERT I CAL EXAGGERAT ION ABOUT 20 DATUM IS MEAN SEA LEVEL Geohydrologic section C- C 1 FIGURE 6.-- Geohydrologic sections of Marsh Creek valley a nd Portneuf Valley, Idaho. (Lines of sections shown on figure 7) . WATER RESOURCES Sources It is estimated from the precipitation map (fig. 3) that about 1.2 million acre- feet of precipitation falls on the basin in an average year. By comparison, Mundorff and others ( 1964, p. 96) estimated l .09 million acre-feet for that part of the Portneuf River basin above Pocatello, a larger area than is covered in this study. However, they used an average rainfall of 15.6 inches (based on a regional precipitation map); whereas the average precipitation computed for the basin from figure 3 IS about 19.6 inches, thus accounting for t he difference in estimates. Part of the precipitation flows out of the basin in streams, part is evaporated, part is transpired by native vegetation and crops. and the remainder seeps into the subsurface to recharge the ground-water aquifers. In addition to precipitation, an unknown amount of recharge is postulated to enter the basin as ground-water underflow through Tenmile Pass and through the gap in the mountains near Soda Point. The postulated flow through Tenmile Pass is questionable and is based on the existence of a possible ground- water continuity and southwestward flow from a water table whose altitude is about 5,950 feet in the Blackfoot Lava Field, to a water table whose altitude is about 5,450 feet west of the pass. If the altitude of the water table within the pass or underlying the basin boundary east of the pass rises above 5,950 feet, ground- water flow would not cross the divide. Subsurface recharge to the basin through the gap near Soda Point is probable because the approximate location of the ground-water divide in Gem Valley as shown in figure 7 is such that it is possible for part of the underflow moving westward through the gap to move northward and another part to move southward. Furthermore, Bright ( 1963, p. 96), in a study of ancestral drainage patterns of the Bear River system, suggested that the ancestral Bear River most likely flowed northward from Soda Point and, thence, through Portneuf Gorge. If that is so, this ancestraJ drainage channel may contain permeable deposits that would aJlow ground water to move readily northward under favorable hydraulic- gradient conditions. lt is not possible at this time to assign meaningful quantitative values to the amount of underflow that may move into the Portneuf River basin from the Bear River basin. N. P. Dion (oral commun., 1969), in a study of the water resources of the Bear River basin, estimated the average annual ground- water underflow through the gap near Soda Point to be about 56,000 acre-feet. Only some unknown part of that would recharge the ground- water reservoir in the Portneuf River basin. Because the geohydrologic conditions at Tenmile Pass are unknown at this time, no estimate can be made of inflow at that p l ace~ if, indeed, inflow actually occurs. In addition to the natural recharge to the Portneuf River basin, some water for irrigation is in1ported from the Bear River basin through the Soda and West Branch Canals. 16 PA PA~O ~ C:OOPUI~T Cih 1111' "..,. ~,.( 6" O(fi'&~TM.t~t 0" lli£C-AV&l ~,1 Well !or "h1.ch hydroq-raph •• •hown raee f i o. B1 Let.t.cr &.note• "'stl1•" eh.o..,n ita t-.aL-le laft•r 'l'o;tss, 1939) Cr-.1n..l9C ballft b0\0n4.l.r.f J .. f 'tif n fl' • FIGURE 7.-- Contours on the water table in fall 1968 and locations of wells and springs. 17 l:h1 :.~d on r<>u!!h cstimal\.'!1 obtain~J from ~ani.ll compJn} personnel. th~ tot.1l importation of v. all'r JlllOUilh 10 about 14.000 Jl:r~ r~~..· t pt.:r } l'.lr On lhl' lllillll'> -.ide .•lhuut 4.000 .Jl'fl' ll:d n l the Uhl:harg~..· of Bi rdt Cn:d. Ill the Portlh'lll R tVl' f bu'illl 1:0. UIVCr(l•d annu.dly tnto l)~.,·v1l C rl'l'l- in th~..· lk.1r Rivt:r h:1~111. Clllhilh: n ng till· unknown:. .lllU tlh: b~..·l.. ()f gouJ (Jlli.lll lltatl \'l' d,ILI . ;.J rough 1.':- tilll.ltC or the tOIJI lll jlll t or Wi.lll'r to lhl! 1\lrtll l'llr RiH:r bai>ill i' i>OillC\o\ hat Ill l'XCC~ ol I .~ million :Krl' r~..·~..·t per Yl'ar. ( ;mund \\ atl'l (,round \\.ttl'r u~o.'l..l lr' in virtuillly cv ~.· ry !!Cll hlg tl untl \"'tlltin t he ba,tn As i>h(m n 111 tahk I. till' m.tior aqlllkr-. (\\i.ttn lw:mng rn ~.. l. 'i) .m· thl' S;dt l.tkl· Fonn.ttion ofTLTt iary :J)!l' .IIlli thl' .tlhiVIlllll anJ ba:-i.llt or Quatl'flli.lf}' ,tgl' 1 h1..• llllllllJll: ~OllfCC or gfUIII\U W:Jtl'f 111 till' a qUifer ~ '' prcdptt.ttion that fajls upon lhl· IJnd 'urhll'C l·h:chJrge to the uquifl'r:. oc~ ur:, .ts t 1 l p r~up ii J it on th.Jt pacllbtc~ to t h~..· H.:gtonul wuter t,1hk . ( 2) lc.ti-Jgc from irri!!.l tion l.Jtl.tl-. .tnd d tldtl''· 1J l 'l'epa~c frum trrtl!.tlcu I arm lal'ld,. t-l) umkrllow I rum tlw :u lt .e.' nt fkar Rl\'l'r h,t,lll 1J,-.tlllll'd ): and 151 k.1l-.tgl· lllltll lh1..· -.nut han part o f th~..· Portncur H l',~r\O i r bu... pcctl'd) (;10\llld \\:Jtl'r dt ... dlafgl'' rrom lhl' aquill'r' hy ( I) l'Vapotran .. ptr:tliOil :JI piJl'l'' Whl'rl' tlh' \\,lll' r t.1hil' 1;.. 11\.',lf IJnJ SttriJCl' or Withlll rl':tCh nr phrl' I tgurl' 7 ~hnws cuntUllf\ dt:J\\ 11 on tla· regHlll,tl w:tl\'1 l.1hk in autumn I 'J<,~ lltl' l'IH110lll\ :I ll' h, t ~l·tl oil \\,tkr k\·\,'( ., ll ll'.t:O.llrl·d Ill tit ~· \o\ l' ll'> ~IHl\\ ll Oil thl' lllap :JIHI 1..'0illll't'l Jhllllh ol l'lJU al .tlttllllk 011 thl' ''·''l'l' 1.1hk lkr.t!ISl' IIHhl ''"· 11 ., 111 \ l..' lllllrtl·d dunng thh 'tudy "' crL' tfrt!!ation Wl'll'>. l'llOugh data "l'l'l' oht.unl'd 111 Cllll tou r 1 he \\ .tll'r t,thk only 111 111 ajor ar"·a:. ol ground \\ ,tfl'r irngation. ( , round \o\,tll'f 111 thl' ba:-111 1:. ~..·nlhlan t l~ 111ll\ lllg UndL't n.t ltll.tl -.und it1 o n ~. it 1110\l'' from .tre.e-. ol n:dt,trgl' dO\\ n the hydrJttliL grad tent t11 .trl'." 111 d'""h.tr;.:~..· T hl' dtrl..'ltlllll ol n.tllll.tl ~ntllnd \\iltl'f ll10VL'tlll'l11 I' pl'rpl'llllllttla r to lh1..' ;.:rnund \\;ttl'f .:olltlHir.,: thu..,. a., ... lul\\n on thl' llt~IJl )!JilUild water 111 thL' h (ot\llltlll \\,11~·• 111 thl· h:t:>lll tl\l.llr' lllldll "'•lilt \\,ll1..'r l.thk .end .t rll..'\1,111 ,·cmdtiJOih. \lo,t ur I hl· v. db t.tp ".tll't l.thk :IIJII IIl'r' hut atll,l.tll .tquikr' .Ill' l .l pp~..·d 111 pl:t~L'' Wl'll c,~ J 18 arh:s1an Jquifer. Wdl 7S 391- 14dhd. at llah.: h, rcpo rt l"d l}' tluw, at tlllli!S anu a number ol otht•r wclb ncar Hatch have :.hallow water levels tlwt an.· h1ghcr th.111 the rt•giu nal '-"'Jtcr tahk Th o~e ~.:ondition~ indil"atc that an a r tt.·~ ian aquifer. probably or apprcciabk t'Xtent. occur!'> 111 t ill' vkinity of Hatch. T ublt: 2. taken from ·1 wb~ ( 1939). ll!->t~ data pertuinin!! to llowing welb in the vicinity of Arimo . The Gl·nerally. v.dl!-> an: drilled only lkcp enough to ohta1n wakr lor the ncc.::d:. aL hand I hu .... lkep gl'ologll anLI hyurologi.: Jat.t Jrc lacking in the ba,in Recent geophysical work done Ill Portneur JllJ Gem Ya l ky~ cMabcy and Orkl. J()(,l)) IIHitlalcd that the t.:entral part ol tht:'\c valley!:-. t!:l !:ltructurall} a trough (grCJbcn) that 1:> lkc pc~ t tn the arcu north or Ban croft and that ma} contain a:. much :.h l:LOOO feet ol Tertwry (Salt Lake Formation) !\lrula ov~:r l ai n hy } <>ung~.·r ba:.alt and alluvtal dcposth. II the:.~.· ~ lr <.t i J arc porou and pcrn11:ahlc. there IS a trelliC.:llUOll~ volume of ~;round \\<.lll'r Ill toragc tn lhl''>l" valleys. WJ tcr Level f luctuations A:. ;1 part of thb stmly. six wdb were :.l'lcdcd to monitor lo r fluctuations in ground wa ter levels. Three of tht' wl'l b were cquippcd with .:ontinuou~ water I cvel rct.:orders :.tnd three \\Crc measured periodically. Tht· localllHlS o f till' obsnvation wl'lls Jre :.hown in figu re 7: thl' hyJrogr<.tph r~.·n.>rd h)r each i' ..,]ll)wn 111 ligun: X. Ex..:cpt for well 9S 39l· 2ch( I. tht• record~ l \lilt! krill \ ,tri.tlion~ 111 water k vd in the Portm·ul Rtva ha:-111 arc unknown, hut in -.nnil,lr or lll'arh} ha~111~ \~ hcrt.' r~con l -; ure availahk. h) drng.raph~ arc used to corrclah.' \\illt'r kvcl changt•, \\ith other known hydrologic cvcnl!. Unuer na turalconl.litions. watl'r kvcb arl' generally highest in the ~pnng during the p~o.•riod of maximum recharge: tk•dmt• through the sunun~o.·r when cv:.~potrunsp 1 ration rak~ an· high and di-.chargc cxct>t·d~ rt•t· h:.~r~t.·: tend to kvd out. but continue downward. in tlw fall : Jn: lowest in wintl'r when mo:-.l 19 Table 2. Characteristics of flowing wells in the vicinity of Arimo, Idaho. (From T\.riss, 1939.) Flow in Temp- Elevation Depth erature Well Owner Location (feet) (feet) gall9per m1n. (OC) Remarks A. Charlie Fink NW~ sec. t8• T. 10 4,630 380 11.! 15~ S. , R. 37 E. B. Charlie Fink NW!a sec. 18, T. 10 4,627 410 21.! I 14 3/4 S . , R. 37 E. 1 c. Mr. Cole S\\1 4 sec. 7, T. 10 4,640 - 1!.j I 14 3/4 S., R. 37 E. D. J. E. Goodman NE!j sec. 8, T. 10 4,660 300: 8 20~ Pressure very good S., R. 37 1:. (relatively) E. Aaron Evans SE~ sec. 9 J T. 10 4,650 425 1~ 16~ ... N 0 S., R. 37 E. F. Leland Evans SE~ sec. 19, T. 10 4,660 425 2 17 s .• R. 3r G. Aaron Evans S\~!,,SE~.~ se . 19, 4,690 425 ( ?) 3 I 17 T. 10 S., R. 37 E. II. L. D. Hickman SW cor., NE!a sec. 36, 4,637 sao! 15 lS!i T . 10 S . , R. 36 E. I. Mr. Ames SW!a sec. 19, T. 10 4,625 - 4 19 Very gassy S., R. 37 E. Very gassy J. Mr. Ames S\~!a sec. 9, T. 10 4,625 - 12 I 191-s S., R. 37 E. Very slight head K. W. A. Morson SW cor., W!a sec. 4,680 - 2 I 17 36, T. 10 S. , R. 36 E. I Aquifer at 382 , T. 4,880 570 Small - L. Carl Olsen NE!-4 sec. feet 11 S . , R. 37 E. fraction Tabla 3. Oteaical analyses of "•tor in the POTtnouf JUvor basin. {Otulcal c.on.sticuents etpressed iJI ailliereas per liter.) Di&Jolved solids Ha-rdness Location or oS:J9f·31~aal 12· 4·68 10 63 65 20 20 4.1 282 0 36 17 0.2 0.4 359 365 Sl9 8.1 0.6 Flwing well 7S·lSE·Zl~dl 25 77 31 43 8.6 370 47 46 .z z. 7 458 320 16 777 8.2 1.0 7S-3bE-2laedl 10·30·SI II 2.5 Z/0.44 ss !3 10 17 .00 .1 232 162 6.8 160 b Zldcbl l·22·6Z -y.oo o.oo 48 21 38 39 0.03 21 .22 1.1 400 220 8.S 208 b 21d ·s.J9E-Jo• •Abl 7-ll- 68 29 120 53 24 8.3 S7b so 27 .3 9.0 S97 604 516 44 981 7. 7 0.03 .s ~~ - l9E- ld•dl 7-ll-61 a2 l8 ls6 820 42 D .2 J.S m 75/ 684 7.4 b 113.bbl 7·25-~6 9 3.4 .00 .oo 86 u .07 51 .10 ~3"2 J90 nbad 7-25-56 9 3. s .o 102 64 .20 Sl .l 610 l_/472 7.4 3~ b 9S-J6£. 2ddc I 6 30 88 33 6.3 397 10 43 35 .I 4.9 468 480 364 22 769 8.3 0 •sa .a 9S-lSC-20d 30 80 47 9,7 672 0 49 . , 13 us 546 1.070 8.0 .09 .9 12- 3-b8 l9 81 17 S4 25 302 0 3.6 41 .5 6.9 •19 172 0 617 S.l 1.8 PIO'fl nc well IJS·J11 -27ddbl 1:- :-os lU 20 61 14 I. 2 271 0 13 3b .2 4.0 309 U9 36 552 7. 7 0 IC> 35 68 •• 6.7 321 45 51 O,J 2.0 437 232 20 716 8.1 10 25 1.1 rortneur ~H·•n ncar 0.04 11 .3 Un "tf'l'ti~Jd 1; l1 18 9.4 J.O 11!0 u II .3 • 7 207 200 166 18 llu lti 17 70 22 4.9 38 .J .. 349 3U 236 26 571 8,4 9 .. l'ortocuf RLvcr IIL'tl rcobbl..: 19 7-22·60 20 7 .o Sl 17 •. 7 311 0 l2 17 .3 ,4 320 ll6 268 12 SH 7.8 .04 12 .5 'orrnoe-uf Rl:ver lle..J"t ro.rtneui zo 8-29-59 18 34 0.02 70 31 so 10 359 48 .. 1.2 473 074 302 0 •n a.J 26 1.3 Zl 68 22 28 302 31 .2 1.3 365 260 13 605 8.2 10 19 .8 • l'1.1rtneut Rhor rn ..u rocotc J J 22 5.a 30 .2 3.1 358 ISS 260 21 604 7. 8 10 18 .1 a ------,~~~~------,"~~----4~-~3~-~su~~·~---~s~----~----~----~ss~--~slr---3~9r---,~.wa--~JO"lr--w----s~~r-~~--~•'~'----~.•r-~zr.~,--~,~9Q~--s~t~t--~2~&~2--~l-~•---,6~4~2--,8r.~z---wr--~~--~--~~-----~--or------ R..tp td l ~ 138 7.3 IS 17 ,4 nt"..ar '""~ 3 ll 16 4,2 5,2 .8 67 0 6.6 - 5.0 .I 1.0 90 Sl 57 Spdnzs 0.00 67 3& 46 5S O.JO ys6s 324 7. s 318 b .co 51 20 21 .00 YZ14 210 7.4 200 b ;.:s.;t. 3.3 .00 0.00 1l 33 17 0 . 40 32 ,10 322 7. s 322 b .00 .00 62 10 .lO 25 .10 284 7.2 288 b fl._..,.u.Jt.l f l~.>t S)'rint lS ;. 1-57 48 32 .04 .00 u 24 9.0 21! 20 .OS 19 .l 0.0 266 163 0 432 7. 7 23 0.8 a R4dloeb ..iul analysit. avllihblo ('~he~· -.u Lclpa.l s.rnn~> s- g -65 1J7.0S .01 60 28 .Jo L.S yz4o 260 7.5 232 b 32 84 52 25 9.0 470 56 27 .2 6.3 SOl 522 424 38 8&4 7.4 .s Lnv;t 11~1 Srrintts \ ' · L 14 3·20-H ao 29 .07 100 34 127 30 c93 o 78 147 ,A 1.2 776 390 0 1,280 0.34 39 2.8 • l.a v~ ll n s1·r1nau ~mnacsp:tl -srrl nis .0 19 6 .00 182 7.6 176 b 9- s-so 12 !f.O< 4'1 tJ .co .4 ~176 ! I • • U. S L.S.; b - Steto of Idaho £..1 TOt.aJ lr9A 2 1 --Confanuous record 65 -----·Bimonthly measurement I:Ll u 70 ~ Caribou County r....a p::; 6S-38E- 36ddcl ::::::> 2 75 (/) 0 80 ~ H 85 ~ 0 H ril 5 90 t:Q 64 8 ril 15 .• ril I 65 '' I r....a •\ • I • 20 ' I :z '' I 1-l 66 ' \ , ' ' t• ' ' I .. 25 "• p::; / I ' ', ILl , 67 ·-' 8 I I ~ I II ~ I I \ I • 0 I ' 8 I 12 I '' I '• :z:: I 8 Bannock County I '' 40 I 13 ' P4 Bannock County '\ 1 ILl 7S-35E-23coot--1 I IIS-37E- 16bbbl .., I ' Q I 45 14 ' 1968 1969 1968 1969 FIGURE 8.-- Hydrographs of observation wells. 22 evapotranspiration ha:-. stopped: ami n:.c again in the spring to complete the annual cycle. In irrigated areas, th is ~.:yde may he altered considerably. When.: ground - water irrigation IS prevalent. the annual lowest water ll'\I.'IS usually occur in late summer owing to regional pumpagc. as indicakd m well 9S -391:- 2t:bd . In surfac.:c - water irrigated areas, where canal losses and seepage from ticlus may constitute the prindpal recharge. h igh water levels usually occur in late summer. In arcus of mixed irrigation. any combination o f the above events may occur. The common usc of observalion well hydrographs is to uetcrmine long term water- level trends. If water levels annually return to ubout the same position. dnnatit; cydcs being considercu. then recharge to and discharge from the ground water aquifer are in near balarH.:e. However. if water k'.el& follow a continuing long term dedinin g trend. then discharge exceeds recharge and ground water is being mineJ from the aquifer. Thcrl' is no evidence to dare thal any of the aquifers 111 the Portneuf basin are being own..h:velopcd hy pumping for irriga£ion: in fact. ~.:ompari!>on of the water- table map in figure 7 wilh the water-table map of Stearns anti others ( 1938. pl. 19) indicates li ttle. if any. change since the 1928-29 period. However. because long- term continuotts water- level data are lacking in the hasin. son1e or the observation wells selected for use in this stuJy sho uiJ tw measured on in to the future. Thest: measurements would providt:: a record or such watl'r level changes as may occur as a result of usc of the basin's watl:r resources. Wate r kvcb in 53 wells wcrl' measured in late March 1969. These levels were mmpart::d with water levels measured in the same wells in the fall of 19o8. Water level changes ranged from a 6·-foot decline to an 18 foot rise. T he maximum rise was in well 7S-J8E- llaJbl. situated dose to the mountain foothills. indicating that spring rl'l'harge probably had already started at that place. The maximum Transmissivit) is an aquifer ~hurac.:tcnstk Lhut is defined as lhl' numher of gallon:-. of W In s~·pkmher llJML a pumping test was made in well gs 39~ IOadal by thl' ldabo lkpartment o f Rcclamution. Th~· wdl was JHimpo.:d c.:ontinually for o.Jhout 25 hours at a r 23 of about l.S 75 gpm (gullons per minute). During the tcst. the maximum drawdown of water level in the pumping wen was only 0.6 foot. There was no measurable dr;.~wdown of water levels in three observation wells at distances of from 0. 7 to 2. 7 miles from the pumping well. The test data show that the basalt aquifer at the well has an apparent transmissivity of about 3 million gallons per day per foot. Meager data are available on the hydraulic~ of !he wells in the basin. Some drillers' reports contain pumping- rate and water- level urawdown data obtained during perfo rmance tests made upon completion of the wells. These tests are run for various lengths of time and seldom. if ever, is any notice given to rates of druwdown. However. these datu do offer some suggestion of well capabilities. The drawdown a!1ll yidtl data from 44 of the wells listed in table 4 were used to compute spt:cifi c- capacit y values. Specifk capacity is a well function and expresses yield in relation to unit drawdown. The values obtained ranged from 2 to 3.000 gpm per foot of d rawdown. and the median value was 26 gJ')m per root of drawdown. Both the h igh and the low values were for wells that penetrated basalt, thus illustrating the high variability of yieltls from wells in tht! basalt aquifer. This high variability in well yil'lds is inuic.:ative of the fad that thl! ability of the busult to transmit water is also higllly variable. Springs There arc huntlrcds ot springs ancl seeps in the basin. They generally ot.:t:ur ncur the base of small c:.~nyons cut into the high mountain slopes and ncar the base of terraces. at and slightly above stream levels. Both hot (above m~an annual air tempuature) and cold (mean annual air temperature or below) springs occur: the cold, of ~ourse. an:· mud1 more numerous. The springs supply tlomestil: anti irrigation water to many f The approximate locations or some of £he springs in the basin are shown in figure 7. Many were not visited during this reconnab.sancc and all the locations of those shown in Marsh Creek valley wert: obtainetl from Twiss ( 1939). Yildtls from the different springs vary greatly. Mo.my springs in tht.: mountainous a r~as are intermittent. llowing only during thl' wt.:ttest parts or the yl:ar and deriving their discharge from local sources, :-whereas many in the lowt:r valley un:as an.: perennial. Lleriving thdr tlischarge from more extensiw and uistant soun:c~. Crystal Springs (f1g. 7) arc high in the mountains but arc perennial. They provklc the cntm: munit:ipal supply for McCammon uml. reportedly. their discharge i), greatest in June and least in February or March. Numerous springs occur in the upper valley along the nood plain of Portneuf River from where the river enters Portncuf Gorge to roughly 4 miles upstream. The accumulated yidd 24 Table •· Rtoc:ol"ds of' veJ ls. Altit ude: Feet above •an 3r• leYel ; to neare5t tenth where spirit leveled; "hoi~ n•ai>«T and approrl,..te ..~ • .,.. taken frca topocraphlc up •r altl•etn reod••J· Uu of water: I - irTI8atlon; H - da.utic; ~ - lrclust r1&1: P - pui>Hc supply; S - stock; u - unused Depth to ••II : To nurest foot btlo- land sur!ac"; lngely ~ reported dat a, soot depth sOUIIdlnis. lfiUrk I 'I - driller'~ 10!1 avatlable: CA- chemC3l malysh c £ ..atn ova!lablo: yldd - reponed ...u yield 1ft 11"' (cal Canna depth: Feet bel- land surfaco to first p..r£ontlons. t.,r,, per IUih&t~). U>....allv obt.a1ned dudng .tnitial veil per· fono•nce test ah<>rtly a(te· drill inc. Dnwd-. in feet bel"" ~ ell finish : 0 - open end; P - perforated cu1ng: static wat•r leov•l tn 'liell X - open hole. Aquifer Quelr.cl (!) •hero doubtful Qal, Quaternary ~nd/or older alluvh.e, 1ncludu lat.e deposiU Qt, Quaternary travertine Qb. Quaternary or older basalt Tsl. Teruary Salt I.a~c ro ..nloo pT, Pro-l t.nd- surt•cc ""rth C:uing ~'e l l W•ttr let\'tl PWIIp Uso Date of ~oil No. llltitud_, of well DlOJlleter Depth flni sh IJepth Oate II. P. of wtdl Re01arks (feet) Cf•ot) (lnche>) (feet' ( fct't l ••·asurf'd water completion bS-38h-l4adbl S ,HO IS Qnl 11 1965 IS Ill ~JI s.os 9-ZO-b8 19S9 Orlclnal de;>th so ft: loa oS-l9£-19cdal S ,350 12 0 I' Qal J.b4 10-J0-1>8 1964 tog llac!b I 5, JS~ .!80 lb 10 r Q•l.Tslt 7.92 1959 Log 3Zbcbl S,lSO liS 28 X Q.11,Tsl1 13.~3 u 1959 Ori1 in•l derth J2::! f't; 1oti yirld • 750 II"" '" th ISS-ft drawd""'n JJcacl 5,300 II> 0 p Qlll 1.>8 191>6 lld.ul >.390 !10 I~ !0 p 1963 3ldbdl s ,375 16 0 p ~I 1966 Jlddbl s ,375 bS lb 0 p Q<>l .SI 30 1963 J4bbbl 5 .~:5 U! ll 21 p Qoii,TsU ll.41 u 1963 6 p u 1960 s IS Cl ty of ln~OI\; CA 21dcb 1 • .5•o gs lZ p 7S 1955 Ctry of lnk001; rleld - I ,OOD ~P• wlth IJ-ft dt.3~otd0\l"ll;. CA =Idee I 4,540 1>0 11 42 r Qui 31.80 7 .s 1937 Log; "'; odglnul dopth - 485 £t: p~Sps contl nuall)· lldcc2 4,540 8 20 p Qal 7 .s N 1953 ~oa; yield - ISS gpoa with l. 8-ft dr4wdown 7S-J8E-llaccl s ,l7V.8 12 90 p Qal,T•If 10 .bl u 1967 lladbl 5,370 18 18 p 37 .1>6 12- 4- bl 100 1957 lladbl 5,340 li>J 20 bO p 14.87 10·30-b~ 12> 1%2 llddbl 5,3J5 175 X 20.18 10·16-U 125 Loa; yield - I, 200 II'• with 1>8-ft drndO>tn 23cdal 5 ,J07 .0 45 16 39 X Qo11 1.57 10-~-68 50 1!166 Z4abal S,lJO us 12 0 75 l9b0 Y.~ld - 1,1100 liP- 14b4c!l 5,320 132 16 p Qb • .79 10-11>-1>8 100 1966 Log; yield - I ,400 gpoa wl tb SO-f t cSralldown 2Sab01 5 ,JJ0.6 150 Qb 21.32 25 1951 25 TJll!Je •. Records of ~ ells (Cootlnued) LAnd s urface ~p th C3 7S-38E-ZSboal 5,315 lSI Qb b.bl 60 0 1950 lo&; yield I , S80 Ifill with 16·ft drawdo>m 2Scacl S , 3l0.7 1!11 Ql> 60 1965 Log Z5d(tC1 S, 3J0 175 QIJ Lo~ 2f>:lddJ S,3lS 152 lb Qh 19.99 1 9~1 Log; yield - 3, 000 gpot with 1-ft dr•vdc•n 26c.t~l S .3~6. • ISO lb 29 24. 7~ 10-29-68 7S )!IS! Held - 2 . ~00 i1"" wl th 12-ft dra..,·down 18 15.83 10-30-68 60 27ndcl S ,335 17S I) u,.to 10-!9-bS u 3~badl S .335 18 1952 log; yald - 2.330 In'"' >nth 45· f't dT3wdown 36abcl 5,340 188 18 Qlt l 0-JO·b8 100 J9SJ Lo'; tield - I,SBO II"' with 46 .. (;. dt"a~·down 7S·39E· Jdccl 5,355 :!2 Qll 9-25-68 u Origi nal depth · 86 ft ?dedi 5,322.3 IJ 3 to 7.38 9-1o-68 75 1963 9ccdl 5,330 1&5 18 Qh ISO 1954(!) 9dccl S ,336.1> l~S In X Qb 24 .ss 9-25- 68 100 Yiald- l,O~O gpm vith 2·ft dt:cwdoW'll tOobbl s , 550 90 >O Qb 23.5~ 9-26-68 ~0 1959 32 19 Qb 20.95 9·19· 68 u Or l&lnlll depth - 86 ft lOccd I 5. 353. 7 b8 15 Qb 36.90 10- l-68 u 1961 Original d~ptll - 17 fL; ylold - 60 lfP• .. 1 th 30-rc dravdown 12dcd s ,sJO.a 3()7 33 Qal, l'sl S.Sl 10-17-1\8 125 1963 Log; yi.•ld. . I , 200 gpot >ti th 90-ft dr-.tWdown IJcaal 5,491>.0 10 so Qal 3.1a 10- 3-6$ 30 1962 Log; wel l used to flOWi t"CI'Jild ln 1967; yt~ld ... 200 gptll 13ctta.2 5,497.4 60 10 Qal 20 1935 (~) 13dbnl S,SOb. l 97 Lb Qo1 , Qb 19.04 10-JS-68 30 1954 Log; riel 13dcal S ,490 37 18 Qal ? 10- 18- 1>8 s 13dca2 5,490 167 IS 21 Qb 7.5 1954 Log 13ddbl s,•90 10 ll.95 10-18-68 s 13ddcl s ,J88.? 10 -18 - 68 s 14dbcl 5 ,435 40 0 4.08 9-25- 1>8 Flows som~ti.me> ISacbl 5,371 .4 MD IS MO 0 4~ . 8 7 9·2~·68 u 1961 ISbcbl 5 ,370 Ill 16 0 Ql> J 0.97 9- 1-67 u 1961 t.os lbbbcl 5 ,329.0 OS IS 14 X Qb 17.50 1967 loi l 7Ad~ l S,HO ss 16 12 )1. Qb 18.83 9-20-68 125 1955 Yield - 3,000 liP' 26 Tn!>lc J, IO:ccoro!t of weUo, (Coollnu.UI Ll>ll~· Surt.u;c llcptb Ca>lr., 'l(attr level Ptap II!• O.t., of •ell llo. Dlt ttud< ot ~II lll....,ttr Depth Aqu fer O.ptb o.te u.r. c: -~u ( !«l) ((HI) (lftchu) (i"etJ (feel) atuured ·~:or "Wif'l~tto:. ;S-39~- I;cbcl S,3:5 110 (J 13. 11 1956 lbdbcl £,3lU 100 :o ~-23-61 100 1964 Ll>i; yield • CtS·!L1,800 clza.-dctm·~ ~ · ·" :ot>•al 5,335 u 1956 .Ub.ldl 5,335 lb 10 l•on4 1956 so Held • JOO ~I'll vit_b :40-ft dnow.iovn 118 I ' u 135 Ia 33 QI>,Qal" u 191>1 Log; yield - Til"' 100 gpm 3\la.obl 5 0 3JS, <• lOll 16 40 Qh bll 1956 Lo&: yield • 1,160 ~Wit~ negligible dra>o • c!Qwn; CA :lc. 7S-JQ[i.:!$ctol '' 0:60 II I ~ l() Q;ll,hlt :?oSl ll•ll·t>S lUO 1961 Loa: yield - 1,800 ""' •. til ~0 - ft drndo•n ! Deco! UoZI u 175 lb (ll~o39 1:- 7-68 110 1%3 oSlbbal Qb ll·ll·<>! 1960 Ql> 1t~.o.a 10· I·"S ISO 1951 Loi: P"ld • 1,600 gpoa ~ I tb ~-ft dra~dcom; CA !dccl $,517 :::s II Old far. well SJ 7 1.8) 9-10-1>8 u Rrported to cou tdn "s,oJ.M "ar..er" Qb.l'sH 7 ... oU s l9SS Loa; r ield • ~00 Jp111 wj th exceJ· sive dr-ahdowu Ill l•lry) u 5~c t•l s ,576 lb Qb,Qol•. J8,20 70 1963 Lo11: , 1.. 1d - ~ss T! J7 with 183-(t dra.wdown 0 Qb 1954 Loa:,.,.. yi•l~ - aoo lbcbl $,315 115 lb Qb 10,hS II 1966 Log awc11 s,ns 18 so 1954 Lo&; yll'ld • l,000 Ill'" vuh SO- fl dr~wdO\OTI Vbacl i,HJ Ia 110.:9 9-10-bS u 1968 ~e-.. we-ll: not yet ...... ~ 97, ) ; u 10o4al S oS:4 o8 t: :oo 9·10·1>! 100 196; Loa: yield • I ,575 IP- wl th O.o·ft dra•JQ"" 14cccl S,4l0.9 lOS u Old well IScbal 5,450 113 Qb 110.10 10-22-65 75 Log; yuld - 1.3>0 Cl'l' wlth 5-ft dra~do.,, 27 Table 4. Records of ~oells. (Cont tnued) Und· Surface Depth Cas IS·l9E·Ib•ddl 5,440 12 10·14-1>1 100 lt> 275 18 II 0 1954 •ell was never used; pluued at 38 ft Uabbl S,420 Ill· 12.89 11-13-68 p 1909(•) ber&cnty use lor c:ity of Bancroft; CA ~Zbac l S ... zs ISS Qb 14.1>8 1-S0-67 30 p 1935 Clty of hncrofL supply; yield • 300 IP'I With 0.2- ft drawd01m ; CA 27acbl 5,4~0 JSS lS 14 Qb,Qal?, 107.97 1954 Log: yield - 300 Tslf gp411 with 45-ft c!Tawdcwn 34aJdl s, ~•o 170 16 20 Qb a~.J9 l t-12-b~ 130 1967 Lo&; ylold • 1,850 gpoa wl th 1-ft drawd01m &S-40L· Scccl 5,596.~ 140 20 Qb 195.78 u 265 6 173 Qb s 1969 Sew well: not yet used l~cbl S,54S 18 ISO p Qb,Qalf, 1>3.&0 1-30-b? u 1957 Loi: yi~l~ • 610 1•11 rpa wit h 150-ft dralldcwn :1JaaJ 5,508 175 16 0 Qb,Qolf "l.h 10-19-68 2$0 1967 ~.o~: yield - or Tsl! 2,218 8Jlll with 73-ft dra.d01o-n 75 6 1!- l-61 1.961 Loa; yield • :c II'"' with neriL· &lble clu.wdo.m: CA b-J8L-!Il.. cl 103 S9.1J 10-21-68 u Old well 0 Qll,Qal! 1963 Log, y!.,ld - 20 &I"" with 2-ft ciralldown ZOccd t 5(> 12 31.4·1 10-l 1-1>8 lO lOcbaJ so so Qal 14.4S H 1962 Log, yield - 10 RJ'II > 20dbb l 39 10 9.17 12- 7-68 II 21bbbJ zso 16 ISO Ql•,Qal'. &8.99 12· 7-68 100 1963 Log pl ou.:o u l968 Ntw we l1 i not yet used 9S-J9E- 2cbcl 5,410.3 96 b Qb T ~·- .. 10- 7-118 u !dJbl S,49S 131 12 II 0 Ob 30 19!.3 Log; yltld - 1 ,350 epa with n•ghrible d.rDd~n 9udl s,•u.5 b W.09 ll Old w•ll; CA IOJdJI 5,475.4 91 (> Qb! S7 .o• H IIebel s.•so 6 Qb' 63.olt> u lldbbl ~.•n li5 16 60 Qb 6:.11 IO·ll·bil 200 1967 Log Ucdcl 5,415 Qb~ 63.01> 11-12-68 H ISadal 5,495.4 ISO 6 QbT 110. •D H 28 Table •. ~ l,:iu~· sur !ace u.pth Cutr.;: ••II ~at 51 0 1~.!2 H Old ••11; CA p 1964 1~0 Qb" u Old • •11 l!!oltbl s.s~s I• r ~ •• oo 195~ Lee; ytold • l.J.&O lP:• t.lth 9·H dnwdcnm JO.U9 JO llV 16 I' 31.01 4(1 1~63 lAg; yield • 700 ~pa Sdddl lo liS r O.I,Tsll 64 .3S 1966 Log; yiold • •so gpoo wltl> 200-ft dTAttdovn Dd•bl 75 ISbcbl 230 l2 90 IZS 1961 Loa; )'laid • 1, 350 liP" with 6- ft dr3vdown ;o ISO r 0•17,ToiT 1.18. (J I0-29-oa ~o 1965 lA&; yield '2,600 rr- vl th 178-ft dta> Qal (dryj 11S 0 QJI! ,TsU s 19CJZ J.oc; fl""i 10S·l1l· 7ebel ~OO{T) 0 (0001) 11· l·68 s Old ve11 water te"P. 196 C; C:A llubl 4,7lS S8S Qolt ,TsU U.3l II·IJ·to8 :s 1958 LD~, rtcwed •M~ drilled; v11Jaa~ o£ Arao .apply liZ I«> p ~.3S 1961 lAc: yield • HO spa wi th ISS·ft dra> Sabbl 16 JO lo.IS 1962(7) 109 16 r Qal 1954 lo 2~ .47 1964 lobbbl 4 ,14~ 6S 16 11.:4 u 17bdbl 4,!=8 so 18•dbl 4,111 so 1963 !8bcd 1 l, c91 80 16 31 Qal 25 1954 Log; yl~ld - I , 680 liP• with 8-ft drnwdown :ocab) J ,12~ 316 J(o r Qui,Tol! ~0 .ss 1966 l-oi; ~·tdd - 7SO gpoo with 80-ft drawdoooo Z labal 4 .tst.M I<> 21aba~ 4,ao; lb p 30 2leul ;,oos ISS. 10 75 1953 Zkacl ',!170 18 p 3',U 1962 :~cbal 4,915 ~19 lo p Qal 60 1961 Lo,: !"ield • 1,:00 era wi tb 160-ft dra.. down IO r Qal 31.77 1961 Log; yt.e!d - l2S KJa >oith 60-ft 27ddbl J ,b95 I< 97 I' Q:ll p 1959 Lo&; yltld • 300 u- vi th 10S·ft dn,..doom; city of Doo;ney supply; CA 29 Table 4. RtcordJ of "ells. (Ccotlnuo4) wd· Sud•ce Depth Cosln& ··e-ll Water laval """r U•t Date- of Well \0, altltuJe of ••II 01a:Jteter lleo!J, finish AQuifer l!cr.th Potr H.r. of ....11 llcuru (:ttl) (f~et) r.tocht>l 1r~eo (feet) ae.:'und water coorple t 1Im IOS-37l-2sabdl 4,'55 Z3i lo r Qal.Tsl! .lS, So 11-21-1>8 ;s l9bS Loc: yuld ·- I , 200 il"' ""II 1-fl dn> :6d.acl -1,1151 1~0 II p ZS.27 P-1b-bl so 1953 IIS·l7E·l~aal 4,8~~ :::a IO ·> r Q•l ;s 1961 Log; yield - I ,3SO JP- vlth 37-ft dra~ lkd•l 4,80B tc: lc su Qal ~~.sa 9·25-tt$ OS 1959 Log; yield • 780 ll"' with 30-ft dnwdO\Iw.n l~dcdl 4,660 ISO IH,40 10-~l-bS II 12S·~··~· Ho~dl •.~DO ISO 135 Qol 109.9~ H -~··OR u IDSS Log 12S·37f· Wnl J,77S 12 IS ~bud I 4,802 zoa I~ 60 Qal 100 1967 Log; yield • 1,000 gpca with 180-ft dnwdOio'll ~eel 4,750 !~.IS 9-J ~ •.,& ;n IObc.al 4,808 .!~S lb 59 Qol 18. 7~ 9-!-1-t>S 75 l9t>O l.o&; yield • '00 JP• vith U4-ft drawdovn 30 from those springs is included in the river gain between miscellaneous measurement sites 7 and 8 and site 9 (fig. 9). On October 23, 1968, the gain in river flow in that reach. due wholly to ground - water discharge, was about 66 cfs (cubic feet per second). It was about 76 cfs in December 1968. The major hot springs in the basin are Downata and lava Hot Springs. Downata Hot Spring, a recreational site, is located in the SW~ sec. 12, T. 12 S., R. 37 E. Twiss ( 1939, p. 20) stated that the spring has a constant now of about 2 cfs. and postulated that the water obtains its heat from depth. percolating almost ::!,500 feet into the SaiL Lake Formation before it returns to the surface. Lava Hot Springs includes a number of hot springs in sees. ------t!.+-a-R~ 22. T. 9 S-:,-~h.{)Se--w.ate-~~r-ecreat-iooal-si-t-e-and-hea-1-Lh.-spa-.~----- Steams and others ( 1938, p. I 7 I) discussed these springs in some detail and estimated their total now at about 3 cfs. Chemical analyses of water from a number of the springs mentioned above are included in table 3. Surface Water There are four continuous- record gaging stations measuring streum discharge in the basin t hree on the Portneuf River und one on Marsh Creek. The locations of these stations and the basin dramage system are shown in figure 9. Also shown is the locat10 n of,.....,-.th-e,.--ga-g~,-n-g ______station on the Po rtneuf River at Pocatello which, although outside the -area studied, produces a record that .is important to understanding the hydrology of the basin. Historic data are included in boxes near the locution of the long- term record stations shown. Two stations. Portncuf River ncar Pebble and Portneuf River at Lava Hot Springs, were installed in the fall o f 1968: therefore. these short records did not provide an adequate base from which meaningful stream now characteristics could be derived. Figure LO shows annual and monthly mean discharges at three long- term gaging ______;: su-tac:ut'""io...un~s>--'Tulle-period 1955 -68.___was_used_as a basis for comparison because that is thl' total period of record for the station at McCammon. Because the records were not udjusted for irrigation diversions or reservoir storage, the d ischargcs as shown are actual The graphs of annual mean dischargl:S at the comparative stations stay somewhat parallel to one another. Variation in magnitude of the annual mean discharges is largely caused by climatic changes. However. correlation of monthly mean discharges between stations is quite poor. especially during the summer period of June through September when the discharge a1 Pocatel1o falls appreciably below the discharge at Topaz.. largely because of irrigation diversions from the Portneuf River below the Topaz. gaging station. Figure I I shows fl ow- duraflon curves for the three long-term record stat1ons. I he curves, as compiled, show the long-period distribution of discharge without regard to the chronological· sequence of discharge. The curves obscure the effects of years of high or low discharge as well as seasonal variations within the year. Because the discharge records used 31 u .. T£, SU. 1 £S ..tJAiHIAt~~T f lt"t£ 1' [A " PRtP"P£0 •'• C-:lOP£A::.l1C·N WIT~ fH( t t.O:. r. su~vL• 10A~0 tfEPA~T~ !; 'H IJ' 1-f(:t. A-...A.t 0"' .... t Orat nocae areo t.2!t0 squ.ort miles Years of '"orG 1911-67 Moalmum d"chorgr 2,990 ' - l Moran Cteek r.eor Me Co mmon .CXPLJ\NAtiO;ri Con~ll\l;;.ue rr.eor4 ;~aq.1n9 at-auon, od~J.UOno)! d6tb .1.ncluded ln. .UOx 'WI10-t"<' I ('tnqth of recor :.a raaaflov, tn cfa ( =ubiC' (od• p~r .smcotuU: ::e.l:ourec1 Ot!cembc!r .Z ·~ . l96&i t;~, «Jt-i.rnat.ed t.1 rA.Lna9e b4s..tn tol.lndocy t M, u • •••.;,., Oto•.. " •: FIGURE 9.-- Map of the stream drainage system, location of measuring sites, and selected stream discharge data, Portneuf River basin, Idaho. 32 Q z 500 0 u ••.•• ••• ..-Portneuf River ot Pocatel lo til .. · ·· .. Ul ... ·· ...... ··. p::; til Portneuf R1ver t:4 ...... ol Topaz E-1 / tLI .··· til ~ .. u . H ~ ::J u z r--- H II ...... , ------~'Marsh Creek near McCommon ~', '...._ , ', ~-····· · · ·· / Note · ,/'' D•schorge not adjusted for trngot•on ' ,....._ __ ..., diversions or reservoir storage OCT NOV. DEC. JAN. FEB. MAR, APR. MAY JUNE JULY AUG SEPT Q z 0 500r---.---..---.--~---,.- --.---,----r--~---,r---.---,----r---, u Note: til Ul Discharge not adjusted for ~rrigollon d lver s1ons or reservoir storoqe p::; til .. t:4 Portneuf R 1ver ot Poco te llo ····· ..·· ...... /·.. E-1 _.: .... ··· ...... ······ ...... til .··· ··•····· ··· ...... ·.. ..· ~ 200 u ..·· •· H ~ River at To paz 0u z H ,.,- --' ' I /'...._, __ __, ,~// ',,"\... /_, '--- I ----"" --~ "' 1 ""--Marsh Creek near McCommon ...... / 50 t955 1968 FIGURE 10.-- Annual and monthly mean discharges at selected gaging stations for the period 1~55-68. 33 1000 ...... Q z .. ~ 0 ... CJ .. o, Po rtneuf River at Pocatello !i,:l • ...... / (bose period 1920-68} (J) 0 ...... ~ .. "0. !i,:l A.. • ''a. 8 !i,:l "'· ;-..... q ~ '- ~ Portneuf R iver at ~ ' ~ ~'"-\~ Topaz (bose penod ' \ 1920-68) CJ H ', / ~ 100 ' ::J ...... ' CJ '-<>...... _ 'q z Reference po1n t 7--..... ' H used in text- ~ '~ ... Marsh Creek near McCommon/'Q..o, ~' ~ (bose period 1955-68) ~ ~ t9 ...... 0, ~ ~ ::r::~ CJ Note: (J) Discharge not adjusted for trngation H a d1vers1ons or reservo1r storage IOL--L--~--~----~~--~-L--~-L--~--~--~--~__. I 2 5 10 20 40 60 80 90 95 98 99 PERCENT OF TIME MEAN MONTHLY DISCHARGE WAS EQUALED OR EXCEEDED FIGURE 11.-- Flow duration curves for selected gaging stations in the Portneuf River basin, Idaho. (Based on mean monthly discharges). 34 to compile the curves have not been adjusted for diversions or reservoir storage, the curves reflect discharge conditions under past levels of streamflow and irrigation development. The curves indicate that 50 percent of the time, the mean monthly discharge at Topaz, McCammon, and Pocatello can be expected to equal or· exceed 170, 69, and 228 cfs, respectively. The decline in the curve for Pocatello below 220 cfs is due primarily to irrigation diversions upstream. The curves shown in figures 12, 13. 14 represent characteristics of flow of the Portneuf River at Topaz during the irrigation season, May 1 to September 30, only. The curves are based on the streamflow record for the period 1913-15. 1920-68, and are appHcable so long as hydrologic conditions upstream from the Topaz statjon are not altered appreciably. Figure 12 is a flow-duration curve of the mean daily discharge for the irrigation season. It may be used to determine the chance that a specified mean daily flow would be exceeded during that period. For example, the curve shows that for the period of record a mean daily flow of 200 cfs (cubk feet per second) has been exceeded 54 percent of the time during the irrigation season. The low-flow frequency curves shown in figure 13 and the high- flow frequency curves in figure 14 were computed using the log- Pearson type Ill procedure whereby logarithms of the flow data are used to determine the Pearson type Ill cumulative density curve that best fits the data. Figure 13 is useful to determine the chance that the low-flow during a period of time will be less than a given mean discharge. For example, a mean discharge of LOO cfs for any 30-day period of low flow may be expected to occur once in about 7.2 years, and that the same mean discharge during a 1-day period may be expected to occur once in about 3.3 years. Figure 14 indicates the chance tbat the high flow for a period of time will be greater than a given mean discharge. Thus, a high- flow mean discharge of 500 cfs for a 60- day period can be expected to occur once in about 45 years, and a 1-day mean discharge of 500 cfs may be expected to occur once in about 4.5 years. During this study 19 miscellaneous stream-gaging sites were measured at different times to establish a basis for a better understanding of the stream system in the basin. Figure 9 shows the locations of these sites. Instantaneous discharge measurements taken at tJ1e miscellaneous sites in December 1968 and recorder station measurements for the same period are shown in small boxes near each site in the figure. The discharges measured during that period are believed to represent base-flow conditions in the basin. Relative gains in flow in different reaches of the streams are shown by these measurements. For example. the gain in discharge of the Po.rtneuf River between sites 7 and 8 and gaging station Portneuf River near Pebble was 38.4 cfs minus 4.3 cfs and 5.6 cfs or 28.5 cfs. Similarly, the gain in 35 0 z 8 700 tz:l U) p:; tz:l Ill f-4 tz:l tz:l rx.. u H ~ :::lu w z Q\ H .. tz:l (.!) ~ b3 u U) 100 H 0 90 z 80 ld! I 2 5 10 20 30 40 50 60 70 80 90 95 98 99 ~ PERCENT OF TIME DISCHARGE EXCEEDED THAT SHOWN FIGURE 12.-- Flow-durat~on curve of daily flow for Porlneuf River at Topaz , during irrigation s eason (May 1 to September 30) . 300r------r-~--r~rT-----r----~--~--,--r-riiTir------~--~--,-~r-----~ 0 z 83wo (f) ..:I li.. ~ ~3 ll 50 ~------~--L-~~~--~------~~~--L-~~~~------~--~---L--L------~ 101 1.1 I 2 1.3 14 1.5 2 3 4 5 6 7 8 9 10 20 30 40 50 100 RECURRENCE INTERVAL, IN YEARS FIGURE 13.-- Low-flow frequency curves for Portneuf River at Topaz, during irrigation season (May 1 to September 30). Reference point used 200 I I 1. 2 1. 3 1.4 1.5 2 3 4 5 6 7 8 9 10 20 30 40 50 100 RECURRENCE INTERVALr IN YEARS FIGURE 14 . -- High-flow frequency curves for Portneuf River at Topaz, during irrigation season (May 1 to September 30). ..., ·....-:: r ~ '§ rd 0 ·g~~-.------ e ~ - r; _. , g t:: (, I , ": V :X r- I 1 C ~ ' _, g_ w« :=- r; r, ,., i \L c r, ., >...... 0 J . e r. j-