Report of Investigation Utah Geologi~al and Mineral Survey No. 130 Shallow GrQund Water Occurrence in Northeastern Utah Valley, Utah by Robert H. Klauk, Geologist Urban and Engineering Geology Section March 1979 TABLE OF CONTENTS Page Introduction 1 Geographical Locations 1 Physiography 1 Geology 4 Hydrogeology 5 Water Table Aquifer 7 The Investigation 9 Conclusions 10 Selected References 11 Appendix A 12 LIST OF ILLUSTRATIONS Figure 1. Index map of study area in northern Utah County, Utah. 2 Figure 2. Block diagram of northern Utah Valley. 3 Figure 3. Map of-direction of shallow ground water flow in the Highland, Utah area. 8 Table 1. Generalized section of Tertiary and Quaternary formations. 6 Plate 1. Map of areal extent of potential shallow ground water problems in northeastern Utah Valley, Utah County, Utah. In pocket Shallow Ground Water Occurrence in ~ortheastern Utah Valley, Utah by Robert H. Klauk, Geologist Urban and Engineering Geology Section March, 1979 INTRODUCTION In the spring and early summer of 1978 shallow, unconfined ground water ~n the Highland, Utah area (northeastern Utah Valley) produced flooding in basements and excavations in new single family dwelling subdivisions under construction. Due to the occurrence of shallow ground water in a rapidly developing part of Utah, an investigation has been conducted to attempt to define the extent of the problem area. The study, which was carried out periodically from June 1979 through December, 1979, included 4 days in the field. GEOGRAPHICAL LOCATION The 48 square miles investigated are located in northeastern Utah Valley, and encompass sections 22 through 30, T.4 S., R.l E., sections lthrough 5, 8 through 17, 20 through 24 and 30, T.5 S., R.l E., Section 19, 30 and 31, T.4 S., R.2 E., and sections 5 through 8, 16 through 22, and 27 through 35, T.5 S., R.2 E. (see Figure 1). Communities.located in this area include Alpine, American Fork, Highland, Lehi, Lindon, and Pleasant Grove. PHYSIOGRAPHY Northeastern Utah Valley is bordered on the North by the Traverse Mountains, on the east by the Wasatch Range (the eastern- most extent of the Basin and Range Province) and on the southwest by Utah Lake (see Figure 2). The Valley was formerly a bay in the Pleistocene Lake Bonneville Basin with the high water level -2- 1/ ..... .../i...; .. -J!.-. --.~ II UTAH SCALE 0i::::=::::i;==::::f?==:t:~ ===4C:::=::::::l~ Miles EXPLANA TION PZ/2i1 Study area Urban a Eng. Geol. Sec. U.G.M.S. Figure I. Index map of study area in northern Utah'County, Utah. R.l. 130 -3- , ." .~ ... " ....... ~ '.-. UTAH I.. AKE ;\: "- I Urban a Eno. Geor. Sec. .G.M.S. Figure 2. Block diagram of northern Utah Valley (from Hunt, 19f)3, p. 7). R.1. 130 -4- reaching approximately 5100 feet; most present day landforms below this elevation resulted from lake deposition (Hunt and others, 1953). In the study area, rising north-northeast from Utah Lake at approximately 30 feet per mile is a broad plain that extends to Lehi and American Fork. At these two corrununities two broad low alluvial fans were formed which rise above the plain and continue to a 100 to 150 foot bluff formed at the southern edge of the Highland Bench (Hunt and others, 1953). This bench, in turn, rises approximately twice the rate of the aforementioned plain (60 feet per mile) and continues to the base of the Wasatch and Traverse Mountains (see Figure 2). The bench is a delta deposit built into Lake Bonneville by .the American Fork River and Dry Creek (Hunt and other, 1953). Situated between the Highland Bench to the north and the Provo Bench (referred to as the Orem Bench by Hunt and others, 1953) to the south is a pre-Lake Bonneville alluvial fan on which Pleasant Grove is located. This fan was formed by Battle and Grove Creeks. To the southwest of this fan and extending to Utah Lake is the same broad lake plain mentioned previously. South of Pleasant Grove is the Provo Bench which was formed by deposits brought into Lake Bonneville by the Provo River. West of this bench are several north-trending ridges a few hundred feet in width and from 5 to 10 feet high. These ridges are sand bars formed in Lake Bonneville (Hunt and others, 1953). GEOLOGY The Utah Valley floor in the vicinity of and including the study area is composed of sedimentary Pleistocene Lake Bonneville -5- deposits interbedded with outwash from glacial moraines in the Wasatch Range (Hunt and others, 1953). Recent fluviatile deposition overlies these lake deposits. Beneath the aforemen­ tioned deposits, hereafter to be referred to as €he Lake Bonneville Group, are several hundred feet of unconsolidated fanglomerate and interbedded lake deposits (Hunt and others, 1953). In the Traverse Mountains to the north is a series of porphyritic lavas while at the northeast corner of the valley a granitic mountain was formed by the Little Cottonwood Stock (Hunt and others, 1953). Pre-Cambrian Paleozoic and Mesozoic sedimentary rocks compose the drainage basins of the valleys in the Wasatch Range to the east. The Wasatch Fault Zone which separates the Wasatch Range from Utah Valley is located along the base of the range. HYDROGEOLOGY The major portion of ground water used in northern Utah Valley (either from wells or springs) is derived from unconsoli­ dated materials consisting of valley fill of Recent, Quaternary and Tertiary age (Hunt and others, 1953). See Table 1 for the generalized section and water-bearing properties of upper Tertiary and Quaternary formations in northern Utah Valley. The four major developed fresh water aquifers in Utah Valley formed during Quaternary and Tertiary time are known as 1) the Water Table aquifer which has an approximate maximum thickness of 100 feet; 2) the shallow Pleistocene aquifer which is located at an average depth of approximately 100 feet with a maximum thickness of approximately 100 feet; 3) the Deep Pleistocene aquifer which is located at an approximate depth of between 200 TABLE I. Generalized section and water-bearing properties of tJPper Tertiary and Quaternary forrnations in northern Utah Valley. From Cordova and Subitzky, 1965, p. II. - . ApproDmate muimwn Geoloalca.e Uolt Web._ Character 01 material Water-bearln, propertiesI (leet) 1 ChieOy unconsolidated alluvial and col­ Fan. yield water to water-table wells POlt-PrOVO 70 luvial depoRts of Ifavel. cobble.. ,enerally within 25 feet of the land deposita and boulders formin, alluvial fans, surface. Stream deposits yield wa.. and .tream-channel depotits of . ter to shallow du, wells on the .....vel alon, perennial streams. flood plains of American Fork R.ecent and Provo Rivers. and Plebtoce.ne( t) No walla known in Chi.:2rm uppermoat the area that ob­ enta ill Utah taiD. water from Wk•• these deposit.. 1---------1-.... Unconformity 'I 1 '4 "> I An extensive crave) member forma delta an4 m embankmeDta. A thinner and 1... exteuive I Provo sand member forma ban in the deltas. A Water fa obtained chieny from sprin,s risin, Formation ailt member and a day member .... COnfIDed aloD, the toe of the Highland and Provo to'deep-water deposita. benche... Coarse deposits yield water to shal­ Unconformity­ low water-table wells on the benches. The I wella ran,e up to about 100 feet in depth. Bonneville 250 Chieny Jnvel and I&Ild; predominantly form Contains fine-Ifained sediments which over­ J'ormation embankmeD~ depoalts. He the pre-Lake Bonneville deposits and serve Pleistocene 'Unconformity as a confmin, cap for the underlyin, artea­ ian Iystem. Wells yield less than 100 gpm. Alpine Principally ailt and clay; some .....vel and sand rormatioa. mainly near caDyoD mouthi. Unconformity . Includes the shallow aquifer in Pleistocene de­ Consist of at least ODe ,1acia1 moraine of pre­ posits (top is a maximum 01 about 250 feet Lake Bonneville a,e and deposit. of several below the land surface) and the deep aquifer Pre·Lake .too pre-Lake Bonneville lake... These lake depoa­ in Pleistocene deposits (top is a maximum of Bonneville about feet below the land surface). its are ..pa~ted by fan,lomerate. and other 400 Most de.,a.ita DuviaWe heda. wells tap these aquifers and yield up to 2.300 JPDl of JOOd-quality water but com- mOnly yield from 100 to 300 JPDl. ~~-----------4---Un~nfonmty---r----------1r--------------------------------4---------------------------------- Yields are variable. Well. near Lebi range in , Pyrocluticl, lanllomerates, fresh-water lim... yield from 60 to 100 gpm; deep wells drilled Undifferentiatecl ston.., and tuflL at the Geneva Steel Plant yield from 2,000 depolita to 3.900 IPm. The quality of water obtained f from these deposits is suitable for most uses. ll\oom aeoloIlc IeCt.Iou by HUDt and othen (1953, pL 4). aweD cleptha from HUIlt and othen (1953, pL 3). Urban a Engineering Geology Section U.G.M.S., R.1. 130 -7- and 300 feet with an approximate maximum thickness of 200 feet; and 4) the Tertiary aquifer of which the depth and thickness are highly variable. It is primarily the sand and gravel layers of these major deposits that contain water; the sand and gravel tends to be coarser, more permeable and more extensive near the mountains, becoming progressively finer and less permeable toward the center of the valley (Dustin, 1978) ~ Recharge to the Shallow and Deep Pleistocene aquifers in addition to the Tertiary aquifer in the study area is primarily from the Wasatch Range while recharge to the Water Table aquifer is from direct precipi­ tation, irrigation, and unlined irrigation canals in addition to the Wasatch Range. Seepage from waterwa~$ and from land irrigated with water from perennial streams in the study area is approxmately 30 percent (Cordova and Subitzky, 1965).