UNIVERSITY OF ILLINOIS LIBRARY AJ iirba na-cuam paign - -2:-dQ HERTZBERG — NEW METHOD, INC. EAST VANDALIA ROAD, JACKSONVILLE, ILL. 62650 | NW41G TITLEN0 ACCOUNT NO. LOT AND TICKET NO. i i 07200-.. *22 OA 54 -. i75 m | OLCQTT*»* ^ I GEOLOGY AND WATER RESOURCES OFttWXNOvL AGO COUNTY * WISCONSIN#

13 36 R.15 E. 7 / Well Wi-19/15/34-213 Winnebago County — Township Range Serial number of well Section Figure 2.—Well-numbering system in Wisconsin. 6 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN The second part of the well number, based on the Federal system of land subdivision, lists the township north of the Wisconsin base line, the range east of the fourth principal meridian, and the section number of the well location. The third part of the well number is the serial number that is generally assigned in the order that the well was sched¬ uled in the field. Numbers assigned to rock outcrops are similar but have an “R” preceding the serial number. Because of space limitations, only the serial numbers of wells and outcrops are shown on the maps in this report. GEOLOGIC SETTING AND HYDROLOGIC CHARACTER¬ ISTICS OF ROCK UNITS Sedimentary rocks underlying Winnebago County form the reser¬ voirs, or acquifers, that supply water to industrial, municipal, farm, and domestic wells and contribute the base flow of streams. The movement of ground water is controlled by the physical framework of the rock units. A knowledge of the geologic setting and hydrologic characteristics of these rock units is necessary to an understanding of the hydrology of the county. The lithology and water-yielding characteristics of the rock units in Winnebago County are summarized in figure 3. The bedrock geology and the topography of the bedrock surface were mapped from well-log and outcrop information, and are shown on plate 1. Ordovician rocks generally are more extensive and have a slightly different configuration than shown by Bean (1949). Con¬ tours on the bedrock surface in the southern part of the county gener¬ ally agree with those shown by Alden (1918, pi. 2). The subsurface geology of Winnebago County, as determined from well logs, is shown by a fence diagram (pi. 2). The diagram is an isometric projection of a series of intersecting cross sections, based on information from wells shown in the index map (pi. 2). It shows the attitude, thickness, and relationship of the geologic units under¬ lying the county and the relationship of the bedrock, land, and piezometric surfaces. PRECAMBRIAN ROCKS The lower boundary of the ground-water reservoir in Winnebago County is the surface of the crystalline rocks of Precambrian age. These rocks are composed principally of granite, as reported for the wells that reach the Precambrian surface, but other igneous and metamorphic rock types probably exist in the county. Precambrian rocks prevent the downward movement of ground water from the overlying sedimentary rocks. They are devoid of water except for a limited amount that may be found in fractures. GEOLOGIC SETTING, HYDROLOGY OF ROCK UNITS 7 LITHOLOGY Upper part, clay, silt, and sand, red and pink, strat ified to unstratified sorted to unsorted; lower part, clay, silt, sand, and gravel, gray and brown stratified to unstratified sorted to unsorted Dolomite, gray to brown massive, fossiliferous; sandstone at base, coarse- to fine-grained, gray, shaly, dolomitic; chert (a) Sandstone, very fine to coarse-grained, white, gray, and pink, dolomitic shale, conglomerate, and siltstone in basal part sandy, dolomitic; some chert (■*) Dolomite, gray to brown some sand and shale layers; some chert, white oolitic (a) Sandstone in upper part, very fine to medium grained; siltstone and (or) dolomite in lower part, gray and red, glau conitic (G) Sandstone, coarse- to fine grained; some siltstone and dolomite layers, red and gray, dolomitic, glau¬ conitic (G) Sandstone, coarse- to me¬ dium-grained, some fine to very fine grained, some silt and shale layers especially in middle part; white to light gray, some pink and pale red Predominantly granite WATER-YIELDING CHARACTERISTICS Yield 50 gpm or less from sand and gravel layers and lenses depending on thickness and extent. Recent alluvium not con¬ sidered an aquifer Yield small quantities of water from joints, bed¬ ding planes, and solution channels Yields small to large quan¬ tities of water depending on thickness Yields small quantities of water from joints, bed¬ ding planes, and solution channels Yield medium to large quantities of water de¬ pending on permeability and thickness Not an aquifer Figure 3. —Rock units and their water-yielding characteristics in Winnebago County. The configuration of the Precambrian surface in Winnebago County and surrounding area is shown on the structure-contour map (pi. 3), which was modified from Thwaites (1957). The Precambrian surface in Winnebago County dips southeastward at about 20 feet per mile (pis. 2, 3), and existing data indicate that the surface is fairly smooth. 8 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN However, ridges and knobs rising several hundred feet above the general Precambrian surface have been found in surrounding areas (pi. 3), and may exist undetected in Winnebago County. The knob shown in T. 20 N., Rs. 13 and 14 E., was mapped by Bean (1949). Any ridges and knobs rising above the general level of the Precam¬ brian surface may impede the movement of ground water through the overlying sedimentary rocks. The ridges and knobs not only would form a barrier to horizontal flow of water in sedimentary rocks below the top of these highs, but also would reduce the thickness of over- lying sedimentary rocks. CAMBRIAN AND ORDOVICIAN ROCKS—THE SANDSTONE AQUIFER Cambrian and Ordovician rocks comprise all consolidated sedimen¬ tary strata above the Precambrian surface in Winnebago County. These rocks are predominately sandstone, but dolomite is also pres¬ ent (fig. 3). Although Cambrian and Ordovician rocks do not have the same lithology and permeability, all the units below the upper dolomite unit in Winnebago County are interconnected hydraulically and form a single aquifer, which in this report is called the sandstone aquifer. Water levels in wells in the upper dolomite unit (Platte- ville, Decorah, and Galena Formations undifferentiated) (fig. 3) and in the underlying rocks indicate, at least locally, a poor hydraulic connection. Therefore, the dolomite unit is not included in the sand¬ stone aquifer. Cambrian and Ordovician rocks range in thickness from 0 feet in the northwest comer of the county, in the area of a Precambrian mound, to about TOO feet along the margin of Lake Winnebago (pi. 2). Thickness of these rocks at any location can be determined by subtracting the altitude of the Precambrian surface (pi. 3) from the altitude of the bedrock surface (pi. 1). The dip of the rocks, which generally conforms to the dip of the underlying Precambrian surface (pi. 2), is southeastward and ranges from 20 to 25 feet per mile, in the northern part of the county, to 10 to 15 feet per mile, in the southern part. CAMBRIAN SYSTEM The Dresbach Group, one of the most productive water-yielding units of the sandstone aquifer, is a thick sandstone unit, present throughout Winnebago County. It is composed predominantly of coarse- and medium-grained dolomitic sandstone but contains some fine-grained to very fine grained sandstone. Silt and shale layers are present, especially in the middle and lower parts, and range in thickness from a few inches to several feet. The Dresbach ranges in GEOLOGIC SETTING, HYDROLOGY OF ROCK UNITS 9 thickness from 250 to 300 feet, except in areas of Precambrian mounds or preglacial valleys; it does not crop out in the county. The Dresbach Group rests unconformably on the Precambrian sur¬ face. In Wisconsin, the Dresbach can be subdivided into the Mount Simon, Eau Claire, and Galesville Sandstones in ascending order, but for the purposes of this report it is not differentiated. The Mount Simon has not been reported in well logs and apparently is missing in Winnebago County. Rocks of the Dresbach Group are thoroughly consolidated and do not cave into wells. Layers that are cemented with silica are hard and may cause difficulty in drilling. The Dresbach Group yields medium to large quantities of water to wells. The upper part probably produces the most water because silt and shale in the middle and lower parts reduce permeability and inhibit the movement of water. The Franconia Sandstone, a productive water-yielding unit of the sandstone aquifer, is present over most of Winnebago County except in the northwestern corner where it has been removed by erosion (pi. 2). The Franconia is mostly a coarse- to fine-grained sandstone, but may contain siltstone and dolomite layers as thick as 10 feet. The Franconia has a maximum thickness of about 120 feet in the county. It is easy to drill and does not cave into wells. The Franconia yields moderate to large amounts of water to wells, depending on the occur¬ rence of siltstone and dolomite layers. The Trempealeau Formation, a relatively unproductive water-yield¬ ing unit of the sandstone aquifer, is present over most of the county except in the northwestern corner where it has been removed by erosion (pi. 2). It consists of medium-grained to very fine grained dolomitic sandstone in its upper part and dolomitic siltstone and sandy dolomite in its lower part. Glauconite is common in the formation. The Trempealeau has a maximum thickness of about 150 feet in the county. It may be thin where it is overlain by the St. Peter Sandstone because of an ancient erosional surface on the upper contact. The thick section of Trempealeau in the area of well Wi-17/15/29-33 (pi. 2) is attributed to the presence of an ancient channel which cut into the Franconia Sandstone and which was subsequently filled by the upper sandstone unit of the Trempealeau (M. E. Ostrom, Wisconsin Univ. Geol. and Nat. History Survey, oral commun., 1963). The lower dolo¬ mite unit of the Trempealeau (pi. 1) crops out north and west of Win¬ chester in secs. 11 and 16, T. 20, N., R. 15 E. (Wi-20/15/ll-R52, Wi-20/15/ll-R 53, and Wi-20/15/16-R39). The upper part of the Trempealeau Formation probably yields only small quantities of water to wells because of interbedded siltstone and 10 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN very fine grained sandstone. Small quantities of water may be con¬ tributed to wells tapping joints, fractures, and bedding planes in the dolomite found in the lower part. ORDOVICIAN SYSTEM The combined Prairie du Chien Group and St. Peter Sandstone are about 200 feet thick and are present over about half of the county. The contact between the Prairie du Chien and St. Peter is an ancient erosional surface having a relief equal to, or greater than, the total thickness of the two units. Consequently, both of these units range in thickness from 0 to 200 feet, either unit locally filling the entire interval to the exclusion of the other (fig. 3, pi. 2). The Prairie du Chien Group, a relatively unproductive water-yield¬ ing unit of the sandstone aquifer, is present in a discontinuous belt extending diagonally across the county in a northeast-southwest di¬ rection (pi. 1) and in several areas in the southeastern half of the county. The Prairie du Chien is composed of hard algal dolomite and has irregular and discontinuous beds, which generally range in thick¬ ness from half an inch to 2 feet. Thin sand and green shale layers are common, and the unit contains white oolitic chert which is unique to the Prairie du Chien Group. Water occurs in limited quantities in solutionally enlarged joints, fractures, and bedding planes in the dolomite of the Prairie du Chien Group, and generally only small quantities are contributed to wells tapping these openings. Thin shale layers restrict the vertical move¬ ment of water through the dolomite. Because the Prairie du Chien Group has a lower permeability than that of the underlying sand¬ stone of Cambrian age, it retards the vertical movement of water and thus produces artesian conditions in the underlying sandstones. The St. Peter Sandstone, a productive water-yielding unit in the sandstone aquifer, is present over most of the southeastern half of the county (pis. 1,2). Locally, it is thin or missing in this area where the Prairie du Chien Group is present. The St. Peter is a very fine grained to coarse-grained dolomitic sandstone; however, in areas where it is thick, the lower part generally contains dolomitic shale and silt, conglomerate, and fragments of chert. Generally, the St. Peter is poorly cemented and easily drilled. It does not cave into wells except in the basal shale, silt, and conglomerate zone. The St. Peter is ex¬ posed at the land surface in two small quarries southeast of Eureka (Wi-17/14/3-R14 and Wi-17/14/3-R15) and crops out southwest of the village of Rush Lake (Wi-l7/14/32-R70). The St. Peter Sandstone yields small to large amounts of water to wells, depending on the unit’s thickness and on the content of fine¬ grained sandstone and shale. GEOLOGIC SETTING, HYDROLOGY OF ROCK UNITS H The Platteville, Decorah, and Galena Formations are not differen¬ tiated in Winnebago Comity for the purposes of this report. The three formations will be considered as one unit and referred to as the Platteville-Galena unit. The Platteville-Galena unit, a relatively unproductive water- yielding unit, is present in the eastern and southern part of the county (pis. 1, 2). The unit is predominantly a massive to thin-bedded fossiliferous dolomite, but 5 to 10 feet of course- to fine-grained shaly dolomitic sandstone is present at its base. It contains dolomitic shale layers, which mostly are very thin but may be as thick as 10 feet. Chert is present in the upper part of the unit. The Platteville-Galena unit ranges in thickness from 0 to about 1’70 feet in the county. Be¬ cause it is the uppermost bedrock unit where it is present, and has been subject to erosion, the full stratigraphic thickness is not present in the county. The unit crops out at the land surface in many places along the low escarpment that it forms, especially in the northeastern part of the county. The Platteville-Galena unit generally yields small quantities of water to wells. As in the Prairie du Chien Group, water moves through joints, fractures, and bedding planes in the rock which may locally be enlarged by solution. Low t permeability of the Platteville- Galena unit probably produces artesian conditions in the underlying, more permeable sandstone aquifer. DEVELOPMENT OF WATER FROM THE BEDROCK AQUIFER High-capacity wells in Winnebago County, including industrial and municipal or public supply wells, tap the sandstone aquifer. The upper part of the Dresbach Group, the Franconia Sandstone, and the St. Peter Sandstone are the most productive formations, but small to moderate amounts of water are obtained from the Prairie du Chien Group, the Trempealeau Formation, and the middle and lower part of the Dresbach Group. The Platteville-Galena unit generally con¬ tributes only small quantities of water to wells. Generally, domestic and farm wells tap the Platteville-Galena unit or the upper part of the sandstone aquifer except in areas where the bedrock surface is deeply buried by unconsolidated deposits of Quater¬ nary age. All bedrock units generally yield enough water for domestic and farm use. AQUIFER CHARACTERISTICS Aquifer characteristics express the capacity of an aquifer to transmit and store water and are a function of the geologic characteristics of the aquifer. A knowledge of aquifer characteristics is necessary for pre¬ dicting the effects of pumpage on water levels and for determining 780-197 0 — 65——3 12 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN the volume and velocity of water moving through the aquifer—hence for determining the availability of water. Aquifer characteristics are expressed quantitatively as the coeffi¬ cients of transmissibility and storage. The coefficient of transmissi- bility is defined as the rate of flow of water, at the prevailing water temperature, in gallons per day, through a vertical strip of the aquifer 1 foot wide extending the full saturated height of the aquifer, under a hydraulic gradient of 1 foot per foot. The coefficient of storage is defined as the volume of water released from or taken into storage per unit surface area of the aquifer per unit change in the component of head normal to that surface. Aquifer characteristics may be determined by measuring the rate of drawdown of water level in a pumped well and in nearby observation wells as water is withdrawn from the aquifer at a uniform rate. These data are analyzed by the Theis (1935) nonequilibrium formula to determine the coefficients of transmissibility and storage for the aquifer. The nonequilibrium formula assumes that the aquifer is (1) infinite in areal extent, (2) homogeneous and transmits water in all directions with equal ease, and (3) confined between impermeable beds. It also assumes that (4) the coefficients of transmissibility and storage are constant, (5) the discharging well penetrates the entire thickness of the aquifer, and (6) the discharged water is released from storage instantaneously with decline in head. Because these conditions are not fully met in nature, considerable judgment must be used in establishing the validity of the results. An aquifer test of the sandstones of Cambrian age was conducted at the Winnebago State Hospital and the Winnebago County Hos¬ pital, well Wi-19/17/31-39 being the discharge well and wells Wi- 19/17/31-37, Wi-19/16/36-61, and Wi-19/16/36-32 being observa¬ tion wells. These wells are open only in the sandstones of Cambrian age and tap all or most of the aquifer. Water-level measurements were made in the four wells while well Wi-19/17/31-39 was pumped at an average rate of 290 gpm (gallons per minute) for a period of about 27.5 hours and during a recovery period of about 12 hours. It was determined that 20,000 gpd per ft (gallons per day per foot) and 0.0002 are reliable values for the co¬ efficients of transmissibility and storage, respectively, for the sand¬ stones of Cambrian age in the vicinity of the test area. The coefficient of transmissibility of an aquifer is dependent on the permeability and thickness of the aquifer. An examination of logs of wells located throughout Winnebago County indicates that the permeability of the sandstone aquifer is relatively uniform. How¬ ever, the thickness of the aquifer is highly variable and, in general, GEOLOGIC SETTING, HYDROLOGY OF ROCK UNITS 13 decreases from east to west (pi. 2). The coefficient of transmissibility of the sandstone aquifer probably decreases from a maximum of about 20,000 gpd per ft along the eastern edge of the county, where the aquifer has its maximum thickness (pi. 2), to very low values in the northwestern part of the county, where preglacial channels have reduced the aquifer thickness to a minimum (pis. 1,2). Specific capacity expresses the general relationship of the discharge from a pumping well to the resultant drawdown of water level in the well and is generally expressed in gallons per minute per foot of draw¬ down. Although specific capacity is affected by the construction and development of the well and the rate and length of time of pumping, it depends on the coefficients of transmissibility and storage of the aquifer, and it may be used to determine very roughly the productivity of the aquifer. The specific capacities of 140 wells in Winnebago County, open in either the Platteville-Galena unit, the St. Peter Sandstone, the Prairie du Chien Group, or the sandstones of Cambrian age, were determined from data on drawdowns and discharges reported by well drillers. The average and range in specific capacities for wells tapping each rock unit and the number of wells used in the analyses are shown in table 1. It is impossible to predict accurately the specific capacity of a well drilled at any particular location because of the differences of the physical characteristics of the rock units and the differences in well construction and development. Table 1.— Average specific capacities of wells open in units of the sandstone aquifer in Winnebago County Rock unit Number of wells Average specific capacity, in gpm per ft of drawdown Range in specific capacities Platteville-Galena unit_.. _ .. _ _ . .. 60 6.3 0.1-44. 0 St. Peter Sandstone _ .. __ . 18 5.7 . 2-20.0 Prairie du Chien Group .. .. .. . . .. _ __ 12 4.2 . 7-12.5 S andst.ones of Cambrian age ... .... 50 6.3 .8-22.5 BEDROCK SURFACE The topography of the bedrock surface is important in Winnebago County because this surface forms the upper boundary of the bedrock aquifers as well as the lower surface of the overlying drift aquifer. The topography of the bedrock surface is often closely related to the surficial topography, and thus has an indirect control on the drainage pattern in the county. The thickness of glacial drift, which can be determined by subtracting the bedrock-surface altitude from the land- 14 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN surface altitude (pi. 1), is useful for indicating the depth to which a bedrock well should be cased, the thickness of the drift aquifer, and areas of thin drift where pollution may be a problem. The bedrock surface in Winnebago County has been dissected by preglacial and glacial erosion and has a considerable amount of relief (pis. 1, 2). Altitudes on this surface generally range from 450 feet in the northwestern part of the county to about 900 feet in the south¬ western part. In general, the lowland areas in the bedrock surface are underlain by rather easily eroded sandstone of Cambrian age and St. Peter Sandstone of Ordovician age. The highland areas are formed by the dolomite of the Prairie du Chien Group and of the Platteville-Galena unit (pis. 1, 2). The Platteville-Galena unit, covering most of the eastern and south¬ ern part of the county (pi. 1), forms a broad, flat, southeastward- sloping plain on the bedrock surface. The slope of this plain ranges from an average of about 25 feet per mile in the northeastern part of the county to an average of about 15 feet per mile in the southern part. The plain terminates in a northwestward-facing escarpment formed by the edge of the dolomite and an adjacent lowland underlain by the St. Peter Sandstone. The lowland formed on the St. Peter probably underlies most of the marshy Rush Lake area in southwestern Winne¬ bago County (pis. 1, 2). The Prairie du Chien Group is exposed at the bedrock surface in a broad discontinuous belt extending from the southwestern corner of the county to the northern border, roughly parallel to the Platte¬ ville-Galena escarpment (pi. 1). The Prairie du Chien has been deeply dissected and forms a series of hills and ridges, but the unit as a whole dips to the southeast at about the same slope as the Platteville- Galena unit. The Prairie du Chien forms a prominent discontinu¬ ous northwestward-facing escarpment. Sandstones of Cambrian age form the bedrock surface in the north¬ western part of the county and in the Fox and Wolf River valleys. The deep valley cut in sandstones of Cambrian age in the northwestern part of the county (pis. 1, 2) is part of a preglacial valley extending from Waupaca County (Berkstresser, 1964), through Winnebago County under the Wolf River and Lake Poygan, and into Waushara County (Summers, 1965). The valley trends .southward in Waushara County, parallel to the Winnebago County border, and probably connects with a preglacial channel just west of Berlin (pi. 3; Alden, 1918, pi. 2) which may represent the course of the ancient Wolf River. The buried valley underlying the present Fox River (pi. 1) from the western border of the county to Lake Butte Des Morts probably represents the course of the ancient Fox River. The bedrock valley GEOLOGIC SETTING, HYDROLOGY OF ROCK UNITS 15 underlying Little Lake Butte Des Morts and extending southward to Lake Butte Des Morts (pi. 1) also may have been part of the ancient Fox River valley. If this is true, altitudes on the floor of the valley indicate that the ancient Fox River flowed south westward and emptied into the Wolf River in the vicinity of Berlin. The buried valley underlying Rush Lake is an extension of the ancient channel now occupied by Green Lake in Green Lake County as shown by Alden (1918, pi. 2). QUATERNARY DEPOSITS—THE DRIFT AQUIFER Quaternary deposits include all glacial and alluvial deposits be¬ tween the bedrock surface and the land surface in Winnebago County. These unconsolidated deposits consist of clay, silt, sand, gravel, boulders, peat, and marl and are sorted to unsorted and stratified to unstratified. Quaternary deposits in the northern part of the county have been mapped by Thwaites (1943) and in the southern part of the county by Alden (1918). These maps are adequate for the pur¬ poses of this report. Glacial deposits were laid down during the Cary and Valders Stades of the Wisconsin Glaciation (Thwaites, 1943, p. 121). The deposits of Cary age cover the county and fill the buried valleys in the bedrock surface. Deposits of Cary age are gray to brown and consist of mo¬ rainal, glaciolacustrine, and some outwash and ice-contact deposits. Drillers' logs indicate that there is a high percentage of clay and silt in the deposits of Cary age in Winnebago County. Deposits of Valders age overlie the Cary and consist predominantly of reddish- brown clay and silt in the form of ground moraine and glaciolacustrine deposits. They generally are very thin and cover most of the county except the southwestern corner (Alden, 1918, pi. 3; Thwaites, 1943). Alluvium includes Recent deposits of unconsolidated material laid down along stream channels, and peat and marl formed in marshes and lakes. Sand dunes in the northwestern part of the county prob¬ ably formed in Recent times (Thwaites, 1943, p. 141). Quaternary deposits in Winnebago County range in thickness from 0 feet at rock outcrops to a maximum known thickness of 315 feet in the northwestern corner of the county (well Wi-20/14/16-136). Fig¬ ure 4 is a generalized map showing the approximate thickness of Quaternary deposits in the county. These deposits are thickest where deep valleys are cut in the bedrock surface and thinnest where the bedrock surface is high (pi. 2). The thickness of Quaternary deposits at any particular site can be determined by subtracting the bedrock- surface altitude from the land-surface altitude shown on plate 1. 16 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN )Menasha Base from State Highway Commission roadmap EXPLANATION Thickness, in feet 0-40 1 41-80 Figure 4.— Approximate thickness of Quaternary deposits in Winnebago County. Drillers’ logs indicate a nearly continuous layer of sand and gravel along the floor of the buried preglacial valleys, especially in the valleys underlying the Wolf and upper Fox Rivers (pi. 1). This layer attains a maximum thickness of about 100 feet in a few places but generally is less than 20 or 30 feet. Yields of wells penetrating the sand and 81-120 120 + SURFACE WATER 17 gravel generally are small, probably because of a high clay and silt content. There are probably no sand and gravel deposits in the county that are extensive enough to yield large quantities of water to wells. Water in the sand and gravel layer is under artesian pressure and is confined by overlying silt and clay; most of the wells penetrating the sand and gravel flow at the land surface. Water levels in wells indi¬ cate that a good hydraulic connection exists between this unit and the underlying sandstones of Cambrian age. Glacial deposits overlying the basal sand and gravel layer in the buried valleys and throughout the remainder of the county are prin¬ cipally clay, but isolated sand and gravel lenses are present, especially in the areas of the buried valleys. These sand and gravel lenses are under artesian pressure. Small water supplies may be obtained from these lenses. However, the location and extent of the deposits can¬ not be determined from available data. In areas of the county not underlain by preglacial valleys, the limited thickness and extent of sand and gravel layers and the high clay content of the glacial till make the glacial deposits a poor source for water. However, the glacial drift acts as a confining layer for the underlying sandstone aquifer. The limited thickness and extent of recent alluvial deposits make these deposits a poor source of water. It has been reported that some sand dunes in the northwestern part of the county have provided enough water to wells for domestic use. However, the sand dunes normally are not a dependable or extensive source of water in Winne¬ bago County. SOURCES OF WATER The source of all surface and ground water in Winnebago County is precipitation. Water from rainfall and snowmelt either returns to the atmosphere by direct evaporation or by transpiration by plants, remains in the soil zone above the water table as soil moisture, runs over the land surface to streams and lakes as runoff, or percolates downward to the zone of saturation as recharge and becomes ground water. Ground water moves through the aquifer and is discharged to streams and lakes. SURFACE WATER FOX AND WOLF RIVERS Winnebago County is in the Lake Michigan drainage area and lies within the drainage basin of the Fox River and its principal tributary, the Wolf River. Streams and lakes in the county either are tribu¬ taries to, or are part of, these two rivers which flow into Lake Butte des Morts (pi. 1) in the central part of the county. 18 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN The Fox River rises in Columbia County in south-central Wisconsin where it flows within about 1 mile of the Wisconsin River at the city of Portage. There it is connected to the Wisconsin River by a canal. The river enters Winnebago County near Eureka, flows northeast¬ ward through Lake Butte des Morts and Lake Winnebago, and leaves the county north of Menasha. It then flows northeastward to Green Bay where it empties into Lake Michigan. Lake Winnebago divides the river into two distinct sections, the upper and lower Fox River. The upper Fox River flows through a fairly flat, poorly drained area underlain by sandstones of Cambrian age and drops only about 35 feet in the 107 miles between Portage and Lake Winnebago (Smith, 1908, p. 26). This section of the river is characterized by low banks and frequent flooding. The low gradient of the upper Fox River provides little opportunity for producing power. The lower Fox River, underlain by dolomite of the Plattesville- Galena unit, drops about 167 feet in the 35 miles between Menasha and Green Bay (Smith, 1908, p. 29), and provides waterpower for several hydroelectric plants built along this part of the river. The storage and regulated release of water at dams make the flow of the lower Fox River very uniform. Navigation is maintained on the lower Fox by means of 19 locks operated by the U.S. Army Corps of Engineers. The Wolf River rises in Forest County near the Wisconsin-Michi- gan border. In the upper half of its course, north of the city of Shawano, the river is underlain by crystalline rocks of Precambrian age and has high banks, a steep gradient, and many falls and rapids. The river drops 775 feet in the 80 miles between Lenox and Shawano (Smith, 1908, p. 96). The lower half of the Wolf River, below Shawano, is underlain by sandstones of Cambrian age and is charac¬ terized by a low gradient, low banks, and frequent flooding. The river drops only about 42 feet in the 80 miles between Shawano and Winneconne in Winnebago County (Smith, 1908, p. 96). The low gradient and broad flood plains of the lower Wolf River make it unsuitable for dam construction, but private interests have made sev¬ eral waterpower developments on the upper Wolf River. The Little Wolf River empties into the Wolf River and the Lake Winnebago Pool near New London (pi. 3). It drains an area under¬ lain by Precambrian crystalline rocks which are covered chiefly by till. The Waupaca River empties into the Wolf River and the Lake Winnebago Pool a few miles north of the Winnebago County line. The river drains an area overlain principally by thick outwash de- SURFACE WATER 19 posits of sand and gravel resting on Precambrian crystalline rocks. Flow characteristics of the upper Fox River and the Wolf River and its tributaries, which contribute water to the Lake Winnebago Pool, are dependent chiefly on the geology of their respective basins. Stream gages on these rivers are listed in table 2 along with drainage area and average discharge. Flow-duration curves for these gaging stations, show that, during 80 to 85 percent of the time, the flow of the upper Fox, Wolf, and Little Wolf Rivers is principally ground water. In the Waupaca River, the flow is principally ground water during about 90 percent of the time. The Little Wolf River, draining an area of ground moraine and crystalline rocks, has the greatest amount of rapid surface runoff. The Waupaca River, draining an area of outwash sand and gravel, has the least amount of rapid surface runoff. Runoff from the upper Fox and Wolf Rivers, draining areas of outwash, moraine, crystalline rocks, and sandstones, falls between these two extremes. In general, drainage in Winnebago County is controlled by the topography of the bedrock surface. The prominent features of the bedrock surface are expressed in the surficial topography of the county which directly controls the drainage pattern. Parts of the Fox River and most of the small streams flow parallel to the escarpments of the Platteville-Galena unit and Prairie du Chien Group, and to the strike of the bedrock formations; they thus drain the valleys underlain by St. Peter Sandstone and sandstone of Cambrian age (pi. 1). The Wolf River, including Lakes Winneconne and Butte des Morts, and the Fox River at Oshkosh have cut through the dolomite escarpments, their flow being at right angles to the other streams and down the dip of the bedrock formations (pi. 1). LAKES, MINOR STREAMS, A NO WETLAND AREAS Rush Lake, in the southwestern corner of the county, has an area of about 4.8 square miles and is very shallow, probably averaging less than 5 feet in depth. The lake is at an altitude of 821 feet and empties into the Fox River through Rush Creek (pi. 1). Rush Creek drains Rush Lake and the large wetland area in the southwestern part of the county (pi. 1). Eightmile Creek has been partly dredged to connect with Rush Creek to drain the wetland area. Rush Creek has an average fall of about 11 feet per mile in the 6 miles between Rush Lake and the Fox River. The Rat and Arrowhead Rivers also have been partly dredged to drain wetlands. These rivers drain the lowland areas in the north- central part of the county and have gradients of only a few inches per mile. 790-197 O—65-4 20 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN In general, wetlands are concentrated in the low-lying areas in the western and northwestern parts of the county, especially in the Wolf and upper Fox River valleys and in the Rush Lake area. Drainage has reduced the total wetlands area from about 47,360 acres in 1938 to about 32,550 acres in 1961 (Wisconsin Conserv. Dept., 1962). Little Lake Butte des Morts in the northeastern part of the county is below the Menasha Dam and is part of the low r er Fox River. The lake surface is at an altitude of 738 feet and has an area within the county of about 2 square miles. Other streams in the county (pi. 1) are intermittent, generally flow¬ ing only in the spring and early summer and after heavy rainstorms. RESERVOIRS—THE LAKE WINNEBAGO POOL The Lake Winnebago Pool is the slack-water area behind the Menasha and Neenah Dams on the two outlets of Lake Winnebago (pi. 1). The pool has a surface area of about 265 square miles at the elevation of the crest of the dam (Knowles and others, 1964, p. 22). It includes Lakes Winnebago, Butte des Morts, Winneconne, and Poy- gan, the Fox River upstream to about Eureka in Winnebago County, and the Wolf River upstream nearly to New London in Waupaca County. The pool, excluding Lake Winnebago, covers about 7 per¬ cent of the total area of the county. The Corps of Engineers regulates the release of water from the Lake Winnebago Pool for navigation and waterpower development on the lower Fox River. The limits of regulation are from 21 ^ inches above the crest down to the crest of the Menasha Dam during the navigation season (generally from the first part of May to the end of October), and down to 18 inches below the crest during the remainder of the year (U.S. Army Corps of Engineers, 1922, p. 91). True lake level is determined by a staff gage at the mouth of the upper Fox River at Oshkosh which has a datum of 745.05 above mean sea level. The usable capacity of the pool within the limits of regulation is 25 billion cubic feet or about 190 billion gallons (Knowles and others, 1964, p. 19). Changes in inflow from the Fox and Wolf Rivers and their tribu¬ taries for the 1959 water year affected the storage and outflow of water of the Lake Winnebago Pool (fig. 5). The inflow, computed from records of the daily discharge at four gaging stations above the pool, is shown in table 2. The drainage area upstream from these gaging stations is about 75 percent of the drainage above Menasha Dam. The effect of changes in storage in the pool on the flow of the lower Fox River also is shown in figure 5. The outflow was computed from records of daily discharge of Rapide Croche Dam (table 2), at which the drainage area is only about 2 percent larger than at Menasha Dam. SURFACE WATER 21 o v£> 01 oo ° o o Csj r-I o o co o o ° csi ~ CT) LO 00 in cr> 3HIIA1 3dVnOS H3d SN033V9 30 SNOI33IIM Nl ‘30dVH0Sia 1333 Nl '30V1S Figure 5.—Inflow, outflow, and stage of the Lake Winnebago Pool for 1959 water year. Modified from Knowles, Dreher, and Whetstone (1964). 22 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN Water was stored in the Lake Winnebago Pool in the late fall, and then released steadily through the winter to supplement the naturally decreasing flow in the lower Fox River and to lower the pool in antici¬ pation of high spring runoff. Much of the spring runoff from the upper part of the basin was then stored in the Lake Winnebago Pool. The stage of the pool rose about 2 feet from March 30 to April 18. The flow at Rapide Croche Dam was kept fairly uniform throughout the summer as the level of Lake Winnebago fluctuated with the run¬ off from the upper part of the basin. Table 2. —Average discharge of streams flowing into and out of the Lake Winnebago Pool Gaging station Drainage area (sq mi) Average dis¬ charge for period of rec¬ ord (cfs) Period of record Above Lake Winnebago Pool: Fox River at Berlin____ _ __ 1,430 2,240 514 1,101 1,713 399 1898-1962 Wolf River at New London ... . ..... 1896-1962 Little Wolf River at Royalton.. . ___ 1914- 62 Waupaca River at Waupaca ._ .. . ..... 272 237 1916- 62 Below Lake Winnebago Pool: Fox River at Rapide Croche Dam__ 6,150 4,194 1896-1962 QUALITY OF SURFACE WATER Surface water in Winnebago County is hard, has a considerable an¬ nual range in temperature, is locally polluted, and has a serious algae problem in the summer months. However, after treatment of the water, its quality generally is suitable for municipal and most in¬ dustrial purposes. The water generally requires softening before it is used in high-pressure boilers and also may require treatment to reduce turbidity, iron, and manganese. Some industrial uses may require additional treatment. The average quality of surface water has probably remained nearly constant over a long period of time. Analysis of water taken from several places on the Fox River and Lake Winnebago over the period 1896 to 1963 (table 3) show fairly consistent concentrations of dis¬ solved mineral constituents. The variation that does occur probably is related both to the time of year that the samples were taken and to the location of the sampling sites. The quality of surface water fluctuates because of the variable ratio of ground-water discharge and surface runoff contributed to streams throughout the year. During periods of base flow, approximately 85 percent of the time, the streamflow is derived almost entirely from ground water, and the chemical quality is nearly constant. Ground water generally is more highly mineralized than surface runoff. The total hardness of water from the Fox River at Omro, sampled monthly, is shown in figure 6. Total hardness was greatest during the winter Table 3. —Chemical analyses of water from selected sites on the Fox River and Lake Winnebago in Winnebago County and from Lake Michigan SURFACE WATER 23 [Results except for pH, in parts per million. Agency making analysis: Prentiss, G. N. Prentiss, Chicago, Milwaukee and St. Paul Railroad; WSLH, Wisconsin State Laboratory of Hygiene; Davidson, G. M. Davidson, Chicago and Northwestern Railway; DDCC, Dearborn Drug and Chemical Co., Chicago, Ill.] a a I 1 ill i co i i i »-< co •*< oo (N 1 00 00 1 00 • I lOOOOt^t^OO 1 1 III 1 1 III 1 1 III 1 1 III 8.0 8.05 Hard¬ ness (as CaCOj) 1 III KOiOQQOOCO i i i lO 00 CO i^GOOOcOoOO) 1 1 1 ^05 iOCOCy IHHHHHH 1 1 IrHHrHf-HH 1 ' III 1 III 1 III 1 III 165 132 Total solids CO CD O ' 00 © © OJ © 05 © O0CO»-*O5©64»- »© 1 1 1 1 218 168 Fluo¬ ride (F) 1 1 1 1 1 III' 1 till AO 1 1 1 ICOIOW^^ i i 1 i ^ CO i 1 ' 1 O «-H till III 1 1 1 1 1 III 1 till III 1 till III to to © Chlo¬ ride (Cl) HIOIOOOOO^MNOIO *0 ui®u5oided‘0‘doO'-< 4.7 6.5 Sulfate (S0 4 ) 1 1 \ CO iO O © © ® pressure or piezometric surface is higher than the land surface, the well will flow. When the piezometric surface is lowered by pumping or free flow from a well, the aquifer is not dewatered; water removed from the aquifer is derived from compaction of the aquifer and associ¬ ated beds and from the expansion of the water itself. This compac¬ tion of the aquifer and expansion of the water constitute the storage factor of an artesian aquifer. Under natural conditions, an aquifer often is under water-table conditions at or near its recharge area where the formation is near the land surface, but may be under artesian conditions where the forma¬ tion is more deeply buried, down dip from the recharge area. Throughout most of Winnebago County, the sandstone aquifer is under artesian pressure. Water in the sandstone aquifer is confined by the less permeable Platteville-Galena unit where it is present, and by glacial drift throughout the county. The Prairie du Chien Group is less permeable than the overlying and underlying sandstones and probably retards the vertical movement of water between the sand¬ stone units. In its area of outcrop (pi. 1), the upper part of the Prairie dii Chien Group is probably under water-table conditions, the water occurring in fractures, solution channels, and bedding planes. The unit confines water in the underlying sandstones in this outcrop area. Water occurs in solutionally enlarged fractures, joints, and bedding planes in the Platteville-Galena unit. Generally the unit occurs under water-table conditions in areas where the overlying glacial drift is thin. Water levels in wells indicate a general hydraulic connection between the Platteville-Galena unit and the underlying sandstone aquifer; however, locally these units are hydraulically separated. Quaternary deposits in Winnebago County generally are saturated, but because of the high silt and clay content of most of the unconsoli¬ dated material, these deposits yield only small quantities of water to wells. In the buried bedrock valleys, where the drift is thick, small artesian wells may be developed from lenses or layers of sand and gravel confined between layers of silt and clay. GROUND WATER 27 RECHARGE, DISCHARGE, AND MOVEMENT Ground water moves through an aquifer from areas of recharge to areas of discharge. The direction of movement is down the hydraulic gradient of the aquifer, from points of higher altitude to points of lower altitude on the piezometric surface. Because the piezometric surface of the aquifer roughly conforms to the topography in Winne¬ bago County, ground-water movement is, in general, from highland areas to lowland areas. The velocity of ground-water movement de¬ pends on the slope of the hydraulic gradient and the permeability of the aquifer, and in the county the velocity generally is only a few inches to a few feet per day. In dolomite, water may travel at much higher rates through fractures and solution channels. The configuration of the piezometric surface in Winnebago County for the period July 29 through August 4, 1963, is shown on plate 4. Because all the formations in the county in general are hydraulically connected, the map was constructed from water levels in 304 wells penetrating various geologic units. The formations in Winnebago County that contain water under water-table conditions receive recharge by direct percolation of water from the land surface to the zone of saturation. These formations in¬ clude glacial drift that has permeable materials at the land surface, the Platteville-Galena unit where it is overlain by only a thin layer of drift, and the Prairie du Chien Group in its area of outcrop. The formations that contain water under artesian conditions re¬ ceive recharge by water moving from areas of outcrop into more deeply buried parts of the same formation, through overlying glacial material, or through overlying consolidated units. These forma¬ tions include (1) the permeable layers in the glacial material that are overlain by material of lower permeability, (2) the St. Peter Sandstone, (3) the Prairie du Chien Group where it is deeply buried, and (4) the sandstones of Cambrian age. Recharge can also take place by leakage between two formations. For example, if the hydro¬ static head in the St. Peter Sandstone is lowered sufficiently by a pumping well penetrating that unit, water would move upward into the St. Peter Sandstone from the underlying Prairie du Chien Group and sandstones of Cambrian age, and downward into the St. Peter Sandstone from the overlying Platteville-Galena unit and glacial drift. Ground water is discharged naturally from an aquifer by seepage into streams and lakes, by evapotranspiration, and by springs, and is discharged artificially by pumping and flowing wells. All streams and lakes in Winnebago Comity are areas of discharge, ground water generally making up their flow during 85 to 90 percent of the time. 700-197 0—63-5 28 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN A large quantity of water is discharged from the aquifer by pumping and flowing wells. Evapotranspiration is a quantitatively important means of discharge in wetland areas where the water table is at or near the land surface. Little or no evapotranspiration takes place from the deep water-table and artesian aquifers. Springs are not common in Winnebago County and they are not a large source of discharge. Winnebago County is subdivided by topographic and ground-water divides that separate the movement of water toward the Fox River, the Wolf River, or segments of the two rivers. In Winnebago County, three ground-water drainage areas, associated with the upper Fox River, the Wolf River, and Lake Winnebago, are separated by the two ground-water divides shown on plate 4. These ground-water divides conform closely to the topographic divides, and for the most part follow the escarpments of the Platteville-Galena unit and the Prairie du Chien Group (pi. 1). The divides are drawn across Lakes Butte des Morts and Winneconne on plate 4 only for discussion purposes. The lakes are a common discharge point for adjacent ground-water basins, and actual ground-water movement under the lakes is not affected by divides. LAKE WINNEBAGO GROUND-WATER DRAINAGE AREA The Lake Winnebago ground-water drainage area in Winnebago County includes the eastern one-third of the county east of the north- south trending ground-water divide (pi. 4). Dolomite of the Platte- ville-Galena unit forms the bedrock surface over most of the area (pi. 1) and the dolomite is overlain by a fairly thin layer of glacial drift (fig. 4). Recharge to the sandstone aquifer in this area perco¬ lates through semipermeable glacial drift and the Platteville-Galena unit. The ground water then moves roughly perpendicular to the contours on the piezometric surface (pi. 4) from the ground-water divide toward Lake Winnebago and part of Lake Butte des Morts, except in the areas affected by pumping, and is discharged into these surface-water bodies. Because the water table in this area is fairly deep and only a small percentage of the area is in wetlands (Wisconsin Conserv. Dept., 1962, p. 5), evapotranspiration is not a large factor of ground-water discharge. The depressions in the piezometric surface surrounding Neenah- Menasha, Oshkosh, and the Winnebago State and County Hospitals north of Oshkosh (pi. 4) are the result of concentrated pumping. Because discharge of ground water by pumping has been more rapid than movement of water toward these areas, water has been removed from storage, and the piezometric head has been lowered. A steep GROUND WATER 29 hydraulic gradient has been established toward the center of the cones of depression. This steepening of the hydraulic gradient has increased the rate of movement of water toward the centers of pump¬ ing, and some of the water that would have been discharged to Lake Winnebago under natural conditions now moves toward the cones and becomes available to wells. This intercepted ground-water dis¬ charge reduces streamflow somewhat in the area of the cone of de¬ pression. However, about 90 percent of the ground water pumped is not removed from the area but is returned to the stream. About 10 percent of the water pumped is used consumptively. In the Neenah- Menasha area, intercepted ground-water discharge that might have entered the Lake Winnebago Pool is pumped from wells and is dis¬ charged to Little Lake Butte des Morts. Recharge to the Neenah-Menasha area is derived over an area of only about 43 square miles (pi. 4). The recharge area is bounded approximately by the major ground-water divide about 4 miles west of the center of pumping, a minor divide about 6 miles south of the pumping center, a minor divide about 2 miles east of the center, and a minor divide about 2 miles north of the center. Ground water moves down the hydraulic gradient, established by the lowered piezo¬ metric surface under the cities, from the divides toward the center of pumping. Because the area of recharge and the hydraulic gradient are greatest west of the cities, this area is contributing the greatest amount of recharge to the area of pumping. Transmissibility is as¬ sumed to be uniform in the area. The cone of depression, therefore, is most evident south of the area of pumpage, where the hydraulic gradient toward the cities is very flat (pi. 4). If pumpage were in¬ creased in the Neenah-Menasha area to the extent that the area affected by pumpage would expand to the ground-water divides, the divides would move outward and actually increase the size of the recharge area. Induced recharge or leakage from Lake Winnebago and Little Lake Butte des Morts probably prevents rapid expansion of the cone of depression to the north and east. If average annual recharge is about 3 inches (probably a conserva¬ tive estimate), recharge to the Neenah-Menasha area is about 2.3 bil¬ lion gallons per year. Total pumpage in the area in 1962 was estimated at about 1.4 billion gallons per year, or 3.8 mgd (million gallons per day). Because most of the ground water moves toward the center of pumping, there is little ground-water discharge to streams in the Neenah-Menasha area. Recharge to the Oshkosh area, including the Winnebago State and County Hospitals, is derived from an area of about 49 square miles (pi. 4). The area is bounded approximately by the major ground- 30 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN water divide about 5 miles west of the center of pumping, a minor divide about 5 miles north of the pumping center, a divide about 2 miles east of the pumping center and underlying Lake Winnebago, and a divide about 3 miles south of the center of pumping. If annual recharge to the aquifer is 3 inches over this area, the recharge amounts to about 2.6 billion gallons per year. Annual pumpage in the area is estimated at about 0.5 billion gallons (1.4 mgd). The depression in the piezometric surface at Oshkosh is much shallower than in the Neenah-Menasha area because pumpage in Osh¬ kosh is much less than that in the Neenah-Menasha area. Because the area of recharge and the hydraulic gradient are greatest west and southwest of Oshkosh (pi. 4), this area is contributing the greatest amount of recharge to the area of pumping. Some induced recharge from Lake Winnebago and the Fox River also probably reaches the aquifer in the Oshkosh area. This induced recharge reduces streamflow in the Oshkosh area; however, the amount is small compared to the flow of the Fox River and probably is not measure- able. FOX RIVER GROUND-WATER DRAINAGE AREA The Fox River ground-water drainage area, lying between the two major ground-water divides, covers the central and southwestern part of Winnebago County (pi. 4). The sandstones of Cambrian age, the Prairie du Chien Group, the St. Peter Sandstone, and the Platteville-Galena unit all are exposed at the bedrock surface in this area (pi. 1). Generally, the two dolomite units are under water-table conditions. The bedrock is overlain by glacial material that generally ranges in thickness from 20 feet in the highland areas to 120 feet in the lowland areas (pi. 2). Artesian conditions prevail in the thick section of the drift aquifer along the upper Fox River and surround¬ ing Lake Butte des Morts. Many of the wells in these areas are flow¬ ing, the artesian head being maintained by recharge from the high¬ lands adjacent to the river and Lake Butte des Morts. Minor divides separate the movement of ground water toward sev¬ eral streams, Rush Lake, the upper Fox River, and Lake Butte des Morts; however, the general pattern of movement is from the major ground-water divides toward the upper Fox River and Lake Butte des Morts. Ground water from Fond du Lac and Green Lake Counties enters the southwestern part of Winnebago County and contributes to the ground-water runoff to the upper Fox River and Rush Lake. This ground-water movement is greatest in areas where the gradient is steep, such as in the extreme southwestern corner of the county, and is least where the gradient is flat, such as in the Rush Lake and upper Fox River areas. GROUND WATER 31 Ground water is discharged artificially from the Fox River ground- water drainage area by municipal pumpage at Omro and Winneconne, by domestic pumpage from private wells, and by flowing wells along the Fox River and Lake Butte des Morts. Discharge from wells is very small compared to ground-water discharge to the streams. Natural ground-water discharge from the basin is to the Fox River, Lake Butte des Morts, Rush Lake, and the several small streams in the area. The discharge of ground water by evapotranspiration is quanti¬ tatively important in the extensive wetlands where the water table is at or very near the land surface. Wetlands may be either recharge or discharge areas for ground water. In the spring, when the water table is at or very near the land surface, ground water is discharged to streams from the wetlands, and recharge is rejected because of the saturated soil conditions. Ground water is rapidly discharged from the wetlands by evapotrans¬ piration during the warm summer months. The water table declines during this period and, because the soil is no longer saturated at the land surface, recharge can take place. WOLF RIVER GROUND-WATER DRAINAGE AREA The Wolf River ground-water drainage area in Winnebago County extends from the northern and western borders of the county to the major ground-water divide (pi. 4). The sandstones of Cambrian age are exposed at the bedrock surface over most of the area but the Prairie du Chien Group, St. Peter Sandstone, and Platteville-Galena unit form the bedrock along the divide (pi. 1). The bedrock is over- lain by glacial deposits generally ranging from 20 feet at the divide (fig. 4) to 300 feet along the Wolf River and Lake Poygan (Wi- 20/14/16-136). The sandstones of Cambrian age receive recharge through the dolo¬ mite units, which are generally under water-table conditions along the ground-water divide. Recharge also probably occurs by leakage through the thick section of glacial material in the area. However, about 15 to 20 percent of the land surface is covered by wetlands (estimate from Wisconsin Conserv. Dept., 1962) where recharge is rejected for at least part of the year. Ground water is entering the county as underflow along the northern and western border of the county. Ground water is moving toward the Wolf River and Lake Poygan from near the western edge of Waushara County (Summers, 1965, fig. 8) and from 3 to 4 miles north of the Winnebago-Outagamie-Waupaca Counties line (Berk- stresser, 1964, fig. 9; LeRoux, 1957, pi. 5). This underflow moves into the county along the western border between Pumpkinseed Creek and 32 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN the Waupaca County line (pi. 4) and along the northern border be¬ tween the Wolf River and the Rat River. The rate of underflow was estimated by the use of Darcy’s law (Ferris and others, 1962, p. 71) to be 2 to 3 mgd. However, the complexity of the geology and the scarcity of data in the area make this figure very approximate. Ground water in the Wolf River basin moves from the recharge areas toward the Wolf, Arrowhead, and Rat Rivers and Lakes Poygan and Winneconne, which are the discharge areas of the basin. Evapo- transpiration is a quantitatively important means of ground-water discharge because of the extensive wetland areas adjacent to the lakes and rivers. The only pumpage in the basin is for domestic and farm use. How¬ ever, numerous uncapped flowing wells throughout most of the area greatly increase the artificial discharge. WATER-LEVEL FLUCTUATIONS AND THEIR SIGNIFICANCE Water-level fluctuations in wells in Winnebago County indicate changes in storage in the ground-water reservoir. The ground-water reservoir is similar to a large tank or surface reservoir in that water levels fluctuate in response to changes in recharge to and discharge from the reservoir. When recharge exceeds discharge, storage in¬ creases and water levels rise. When discharge exceeds recharge, stor¬ age decreases and water levels fall. However, unlike the water level of a surface reservoir, ground-water levels may rise in one part as they fall in another part of the same reservoir. Variations in the amount of recharge to the aquifer in Winnebago County are the result of areal and short- and long-term changes in rainfall, of variable evapotranspiration rates during the year and from year to year because of changes in air temperature and plant growth, and of changes in soil conditions including frost in the ground and moisture content of the soil. Artificial changes, caused by pumping of wells and draining of wetlands, also may affect recharge. Major changes in the amount of discharge from the aquifer are generally the result of pumping, but natural discharge also varies in direct relation to the amount of recharge that enters the aquifer. Seasonal changes in recharge generally cause an annual cycle of water-level fluctuations. Water levels rise in the spring because low evapotranspiration rates and saturated soil allow a high percentage of water from spring rains and snowmelt to soak into the ground and recharge the aquifer. Water levels decline through the summer be¬ cause most of the rain water is returned to the atmosphere by evapo¬ ration and transpiration or is retained in the soil zone and is not available for recharge. Water levels may rise slightly in the fall be¬ cause of reduced evapotranspiration after the first frost kills plant life. GROUND WATER 33 Water levels decline through the winter because frost in the ground prevents recharge. Annual water-level fluctuations in four wells in Winnebago County (Wi-20/15/19-129, Wi-19/16/19-168, Wi- 18/14/28-235, and Wi-17/16/25-287), unaffected by pumping are shown in figure 7. The amplitude of the water-level fluctuations was not the same in the four wells because wells Wi-19/16/19-168 and Wi-18/14/28-235 (having the greatest fluctuations) are near local ground-water divides, whereas wells Wi-20/15/19-129 and Wi-17/ 16/25-28 i (having the least fluctuations) are near discharge areas. W ater levels were higher in 1962 than in 1963 because rainfall was greater in 1962. However, each of the four wells shows an annual cycle of fluctuations. Long-term changes in water levels, resulting from changes in rain¬ fall and effects of pumping, are shown by the hydrograph of Wi-20/ 17/20-1 from 1946 to 1962 (fig. 8). Total pumpage in the Neenah- Menasha area and cumulative departure from normal precipitation at Oshkosh from 1888 to 1962 for the same period also are shown. Cumulative departure from normal precipitation is the algebraic sum of the differences between average monthly precipitation deter¬ mined for the total period of record and the actual monthly precipita¬ tion. The trend of the water level in well Wi—20/17/20—1 approxi¬ mates that of precipitation, both declining from 1946 to 1950 and from 1955 to 1959, rising or leveling off from 1959 to 1962, and declining in 1963. However, water levels rose or leveled off in the period 1950 to 1955 while precipitation continued to decline. This rise in water levels may have been caused by a decrease in pumping. Pumping effects can be seen in the period 1956 to 1963, when water levels gen¬ erally declined during periods of increased pumping and rose during periods of decreased pumping. Water levels in the Neenali-Menasha and Oshkosh areas have been lowered by a concentration of industrial pumping (pi. 4). Water levels in the Neenah-Menasha area in 1915 were reported to be at or near the, land surface (Weidman and Schultz, 1915, p. 633), but by 1963 they were 110 to 120 feet below the land surface. Pumping has lowered water levels in the Oshkosh area 25 to 30 feet below the 1915 level. This lowering of water levels by pumping is caused by a reduc¬ tion of the artesian pressure in the area, not by a dewatering of the aquifer. Inasmuch as the sandstone aquifer is still saturated with water, present drawdowns are not excessive, and abundant supplies of water are still available from the 600-foot-thick aquifer. The hydrograph of well Wi-20/17/15-17 (fig. 7) shows the effects of pumping in the Neenah-Menasha area during 1962-63. Because a large percentage of the ground water is used for industrial cooling, 34 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN 30VddnS aNV~I M033a 1333 Nl ‘13A33 d31VM H1NOIAI d3d CD 'H 'B u 4-> 03 £ T3 C P o i- 0 OQ CD t? § § 200 GROUND WATER 35 o o o o o o o o ^ m 10 oo H1N0W d3d 30VdanS 0NV3 M0138 SNOTIVD 1333 Nl ‘d31VM 01 Hld30 30 SNOmiW Nl ‘3DVdWfld o O o o o CM rH r"H CM + + 1 1 S3H0NI Nl '3dnidVd3a 3AiivnniAino Figure 8. —Well Wi-20/17/20-1, estimated pumpage in the Neenah-Menasha area, and cumulative departure from normal precipitation, 1946-63. 36 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN pumping is generally greatest in the summer. The water level de¬ clined sharply from May to October when pumping was greatest and rose during the fall and early winter months as pumping decreased. Pumping and a decrease in rainfall in 1963 caused a greater decline in water levels than in the previous year. The many flowing and pumped domestic wells in the remainder of the county and the municipal wells at Omro and Winneconne probably have lowered the water levels only slightly. A well at Omro was re¬ ported in 1915 to have a head of IT feet above the Fox River (Weidman and Schultz, 1915, p. 629). A head of 4 feet above land surface or 8 to 10 feet above the river was measured in Wi-18/15/17-30 in 1963. The many flowing wells recently drilled for cottages and houses sur¬ rounding Lake Poygan and the Wolf River have lowered the piezo¬ metric surface slightly in these areas, but older records are not avail¬ able for comparison. In general, those wells unaffected by pumping that are located in the highland or recharge areas, near ground-water divides, have water levels that are deeper and tend to fluctuate more than water levels in those wells located in the lowland or discharge areas near rivers and lakes. Because the piezometric surface in Winnebago County fluctuates continuously and unequally in different areas, the configuration of the surface changes continuously. Ground-water divides are not station¬ ary but shift in response to changes in recharge and discharge and the cones of depression created by pumping become deeper or shal¬ lower in response to changes in pumping (fig. 7). However, over a long period of time, the average recharge and natural discharge from the ground-water reservoir remains fairly constant, and the general configuration of the piezometric surface does not change except in response to major changes in pumping. Water-level measurements in wells used to construct the piezometric map (ph 4) were made between July 29 and August 4,1963. Precipi¬ tation was deficient in the county for about 9 months before the time of the measurements, and water levels probably were below normal when the measurements were made. Above-normal temper¬ atures were recorded in June and July 1963; consequently, pumpage was above normal and the cones of depression at Oshkosh and Neenah- Menasha were deeper than normal, as indicated by the hydrograph of Wi-20/17/22-17 (fig. 7). QUALITY OF GROUND WATER The quality of ground water in Winnebago County is generally good; however, it is very hard and locally high in iron, and saline water occurs in the sandstone aquifer on the eastern edge of the county. GROUND WATER 37 Dissolved mineral constituents in ground water are derived from the soil and rocks with which the water comes into contact as it moves into and through the aquifer. The concentration depends on the solubility of the rocks, the solvent, and the length of time that the water is in contact with the rocks. Dissolved mineral constituents in ground water, therefore, may become highly concentrated in areas of the aquifer in which the movement of water through the aquifer is retarded, such as in areas having low permeability or in the area of impermeable Precambrian mounds. The source and significance of dissolved mineral constituents and properties of water are summarized in table 4. Where applicable, limits recommended for drinking water by the U.S. Public Health Service (1962) are listed. Water containing dissolved mineral con¬ stituents above the recommended limits is not necessarily harmful or unusable for all purposes and actually may be suitable for many purposes. Partial chemical analysis of water from 49 wells, most of which penetrate the sandstones of Cambrian and Ordovician ages, are listed in table 5. Ground water in Winnebago County ranges from moderately hard to very hard. In the saline-water area in the eastern part of the county, hardness ranges from 600 to 2,200 ppm, increasing from west to east. Ground water in the northwestern corner of the county is only moderately hard as indicated by samples from three wells that ranged from 64 to 110 ppm. In the remainder of the county ground water is very hard, ranging from 200 to 600 ppm. The concentration of iron in ground water in the sandstones of Cambrian and Ordovician ages generally is high throughout Winne¬ bago County. Analyses of 49 samples averaged 1.6 ppm of iron and ranged from 0.02 to 10 ppm. The map showing distribution of iron in ground water (fig. 9) indicates that concentrations generally are greatest along the ground-water divide west of Neenah-Menasha in Winnebago County. High concentrations of iron also are generally associated with areas of fairly slow moving water and marsh deposits. The progressive eastward increase of iron in ground water along the eastern side of the county is associated with the saline-water zone and is caused by restricted ground-water movement. Although iron is a problem in the county, it is not detrimental to health, and it is fairly easy to remove by precipitation, filtration, or aeration. Staining of plumbing fixtures and reduction of the effi¬ ciency of wells caused by precipitation of iron in well screens, pump bowls, pipes, and other areas of turbulance cause the greatest prob¬ lems where the ground water has a high concentration of iron. 38 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN Table 4. —Significance of dissolved mineral constituents and properties of water Constituent or property Source or cause Significance Iron (Fe) Dissolved from practically all rocks and soils. May also be derived from iron pipes, pumps, and other equip¬ ment. Manganese (Mn).. Calcium (Ca) and magnesium (Mg). Sodium (Na) and potassium (K). Dissolved from some rocks and soils. Not so common as iron. Large quantities often associated with high iron content and with acid waters. Dissolved from practically all soils and rocks, but especially from limestone, dolomite, and gypsum. Calcium and magnesium are found in large quantities in some brines. Magnesium is pres¬ ent in large quantities in sea water. Dissolved from practically all rocks and soils. Found also in sea water, industrial brines, and sewage. Bicarbonate (HC0 3 ) and carbonate (CO 3 ). Action of carbon dioxide in water on carbonate rocks such as limestone and dolomite. Sulfate (SO 4 ) Dissolved from rocks and soils containing gypsum, iron sulfides, and other sulfur compounds. Usually pres¬ ent in mine waters and in some industrial wastes. Chloride (Cl) Dissolved solids... Hardness as CaC O3. Dissolved from rocks and soils. Present in sewage; found in large amounts in sea water and industrial brines. Chiefly mineral constituents dissolved from rocks and soils. Includes some water of crystallization. In most water nearly all the hardness is due to calcium and magnesium, dissolved from soils, dolomite, and limestone. Hydrogen-ion con- Acids, acid-generating salts, centration (pH). and free carbon dioxide lower the pH. Carbonates, bicarbonates, hydroxides, phosphates, silicates, and borates raise the pH. Temperature On exposure to air, iron in ground water oxidizes to reddish-brown sediment. More than about 0.3 ppm stains laundry and utensils reddish brown. Objectionable for food processing, beverages, ice manufacture, brewing, and other processes. Fed¬ eral drinking-water standards state that iron should not exceed 0.3 ppm. Larger quantities cause un¬ pleasant taste and favor growth of iron bacteria. Same objectionable features as iron. Causes dark brown or black stain. Federal drinking-water standards recommend that manganese should not exceed 0.05 ppm. Cause most of the hardness and scale-forming prop¬ erties of water; soap consuming (see “Hardness"). Water low in calcium and magnesium desired in electroplating, tanning, and dyeing and in textile manufacturing. Large amounts, in combination with chloride, give a salty taste. Moderate quantities have little effect on the usefulness of water for most purposes. Sodium salts may cause foaming in steam boilers, and a high sodium ratio may limit the use of water for irrigation. Bicarbonate and carbonate produce alkalinity. Bicarbonates of calcium and magnesium decompose in steam boilers and hot-water facilities to form scale and release corrosive carbon-dioxide gas. In combination with calcium and magnesium they cause carbonate hardness. Sulfate in water containing calcium forms hard scale in steam boilers. In large amounts, sulfate in com¬ bination with other ions gives bitter taste to water. Some calcium sulfate is considered beneficial in the brewing process. Federal drinking-water standards recommend that the sulfate content should not exceed 250 ppm. In large amounts in combination with sodium gives salty taste to drinking water. In large quantities increases the corrosiveness of water. Federal drinking-water standards recommend that the chloride content should not exceed 250 ppm. Federal drinking-water standards recommend that the dissolved solids should not exceed 500 ppm. Water containing more than 1,000 ppm of dissolved solids is unsuitable for many purposes. Consumes soap before a lather will form. Deposits soap curd on bathtubs. Hard water forms scale in boilers, water heaters, and pipes. Hardness equiv¬ alent to the bicarbonate and carbonate is called carbonate hardness. Any hardness in excess of this is called noncarbonate hardness. Water of hardness up to 60 ppm is considered soft; 61-120 ppm, moder¬ ately hard; 121-200 ppm, hard; more than 200 ppm, very hard. A pH of 7.0 indicates neutrality of a solution. Values higher than 7.0 denote increasing alkalinity; values lower than 7.0 indicate increasing acidity. pH is a measure of the activity of the hydrogen ions. Corrosiveness of water generally increases with decreasing pH. However, excessively alkaline water may also attack metals. Affects usefulness of water for many purposes. For most uses, a water of uniformly low temperature is desired. Shallow wells show some seasonal fluctu¬ ations in water temperature. Ground water from depths over 60 feet usually is nearly constant in temperature, which is near the mean annual air temperature of the area. GROUND WATER 39 Manganese is present in only minor quantities and is not a problem in Winnebago County. Saline water underlies the eastern edge of Winnebago County, in¬ cluding Neenah-Menasha and Oshkosh, and is part of a large saline- water area, described by Ryling (1961), which includes parts of Brown, Outagamie, Calumet, Fond du Lac, and Dodge Counties. Saline water, as defined by Ryling, contains more than 250 ppm sulfate or chloride, or more than 1,000 ppm total dissolved solids. In Winnebago County, only sulfate and dissolved solids exceed these limits, but other dissolved mineral constituents generally are slightly higher in the saline-water area than in other parts of the county (table 5). The saline-water area is the result of the retardation of ground- water movement through the aquifer by Precambrian mounds east and south of Winnebago County. Dissolved solids in ground water in Winnebago County range be¬ tween 200 and 400 ppm over most of the county, but are as high as 1,700 ppm in the saline-water area (fig. 10). The concentration of dis¬ solved solids in the saline area increases from west to east towards Lake Winnebago. Dissolved solids in water in Winnebago County are made up largely of sulfate, calcium, and magnesium, especially in the saline- water area in the eastern part of the county. The concentration of sulfate in ground water is very high in the saline-water area, but generally is low in other parts of the county. Concentrations range from about 100 to 900 ppm in the saline-water area and increase from west to east as shown in figure 11. Sulfate concentration in other parts of the county generally range from about 10 to 100 ppm. Concentrations of sodium, potassium, and chloride in ground water are low in Winnebago County. Chloride ranges from about 2 to about 100 ppm, well below the recommended upper limit of 250 ppm. Sodium and potassium range from about 2 to 64 ppm. These con¬ stituents have only slightly higher concentrations in the saline-water area than in other parts of the county. The temperature of ground water generally is nearly constant and is slightly higher than the mean annual air temperature. Recorded ground-w r ater temperatures in Winnebago County ranged between 49° and 54°F. The temperature of water from shallow wells may vary slightly with seasonal changes in air temperature, but water from deep wells has a more uniform temperature and generally is slightly warmer than water from shallow wells. The constant low temper¬ ature of ground water makes it an excellent source for cooling water and for other purposes. Chemical analyses of ground water from selected wells in Winnebago County GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN 3 oT 9 .§•2 K-S s-4 03 •5 03 2 £ O ^ £2 rH 3 a 11 •9 d So¬ li x: W°. p CO o O kI El 3P coO * 8 bfiiS oZ rH 18 ail? PL* .® 10 .2 co 1 O o ep CO M o3 »|S ia6S B r § loo 03 to v- M> S ° 9 0 M co ® ill >»co 3 O . 03 GM ™ b£ . co << ^ co . ® .» 0-“ ® o.2 g w Hi o ◄ Eh CO. a •r’S o^co ft.*^ •sjs W -a Qo“ -OO o,a a 8^3 S J§ S'3-3 3 so co « w ft O lO 10 «5 to eo •*< ^ «0 CO »0 Hj< 10 1 1 1 10 T|l co 0 m o> r^- 1 ^- t'- I s - I s * I s - 1 • it^i^r^oot^t^r^r^ 1 1 1 Hardness as CaCC>3 Non- car- bon- ate OOCO(N OMNHNOdW 1 O 1 ^ 1 iQON>00 il^O 1 CO CO N N CO CN N H Tf 1 1 » CM CO 1 1 1 1 10*0^ CM 00 ^ 00 ^ CO i CM ICO i CO 105 00 CO O i 1 i i CM rHCOrHrH rH 1 rH 1 rH 1 rH 1 III! 1 III lilt Mag¬ ne¬ sium (Mg) III 1 1 1 1 1 1 1 1 • » 1 * _ III! Ill i i 1 1 i i l 1 • 1 1 CO » 1 « IHCONN III 1 1 1 1 i 1 i ICO » » 1 1 ^ 00 i i i ‘ Ht< CO CO CO ill i i I I l I I I i ill till ill i i I i I I i i i ill till ill i i i i i i i i I III ill* Cal¬ cium (Ca) III 1 1 1 1 1 1 1 ICO 1 1 1 1 C^l 1 1 1 1 IHIOHU3 iii i i i i i i i i to i i > o> tiii i oo t~- oo o III llllllll 1 III lllll rH III llllllll 1 I II lllll Man¬ ga¬ nese (Mn) III llllllll 1 llllllll 1 00 1 1 III 1 1 1 i i i i iCM 1 i 1 i 1 i i i i 1 o 1 1 III 1 1 1 1 1 1 i i O 1 1 1 i 1 1 1 i i i 1 1 o III llllllll 1 1 1 1 1 1 1 1 1 1 II Iron (Fe) 1 oo co i cm io *o CM ‘O CM rH h 00 lO O CM 00 CM 00 05 0 0 i0^iOCO»0000^ OrH -rt* HH rH CM CO rH 1 rH CM O Water temper¬ ature ( °F) II | lllll 1 1 lO II 1 lllll 1 1 . II | lllll I I CO CM CO 05 rH CM i i CM CO CM i CM 'CO i 1 lO i CM CO ‘ rH O i iO »C iO iO i i iO iO iO • i^O I i 1 ^ 1*0 »o i i ll i lllll i i li i lllll 1 i el o . “> *, *—j u* G .9 2 <§ *r tL 0* -2* g 03 ,2 tf> ^ ft£ ® ® j\4S Q o~ 3 ^ *C > 00 co > rH CM OOOOCOO^OCMO OOOCCCOOOQCOOgNjO SB8|^g>o^oo ^ w H Ifi «s- CO co CO m ab ob ob oo ob ab ob ab ab ab ab 4< ab O) M >0 05 “3 ! co cp >o cc »o < IX ;; i dSe o o o X3Q g ' IT.H. ID Mffl >,s ®® t, C3^ J BSSzo g pj ® .SP fl o®pw-1 o as 5? ® .2 > .9 "ti £2 o £ -*-> 2 G ■ ” .— -4-J co S 3 S £ Efo.&’S ® ® s rp °r CP3P .Oh T3 _ H 0=2 ^3 O’® « s a^ M |o| ? s . o > ^ a o OLP^^303n «P^X O WOPco WOcoPhP^-o t-. 5 ® o ^lO C bo x: 03 ajz CO ® _h a II wi£ ea till 1 1 1 1 l l l 1 S kO CO co fO *o ^ »o co fh r-L Js " H CO 1 • I I I I I I I I I I 1 i i i i : : : : : :JJ (NCO« . .Vi »o co 00 a Hospital, GROUND WATER 41 i-h CO OO OOO^NOOiOiO^OO COO O 0>»ONH(0 oonn aor^r^r-’oor^t^ooocr-’ noo o6 n n n n n (N 04 cO ^ OOONONNOO®® 1-1 'U* CO © OOON»(N " 04 C4-VNON 0*0 0 cp co co t$HNOp©CC«»C cOO^Q^CMCOcOr^^ i-«P4co*-HCOcococot' s - 04 a> * jo a> Op 00 04 00 COOJWO) OCCO ON< o «-< co ^ • CO ^ O *“H i-H ( 04 © CO *C © ^’t 30 Q h CO CO CO ^ o ) *0 (M 00 04 o o «£> 06 e*3 P3 po O O o 4 4. 60 04 04 00 04 O 04 04 04 »C H H *0 1-H ^OOONOO ^H *0 i-h *0 ©*ON CO co»-H*o*^r^oooo^*-0 U5 IO >0 Opg Osp ■Css c/)cowc/)t/)t/)c/)Qi{/)co C/3(/)WC/)(/)(/3«WW(/) cpcpcpvcpvcpovcp ■Css ■Css ■Css ■Css ■Css ■Css ■Css Css 1 1 l 1 1 J i i j 1 1 CO GG o i i i i i i i i i • i i i i i i i i i 1 i i i • i i i i i i cecgggcgcgcgggggcgcg l l i l 1 1 1 1 gg m 1 1 1 1 TJ1 l i i i i 1 1 i 1 • 1 1 1 1 1 i i 1 i 1 CO CO CO CG CG OO o oooooooooo oo O ooooo OQCC cJ 02030302020202020303 03 02 m 03 03 03 03 03 £>t> & <#0® Nif r 1 r-H rH N co 04 co *o *o *o © *o © o *o co o o oo *o co co o © cj co COCOCO 04 CO 04 1-H *0 *C COCO o S CO 0*0 I *C Q ^ CO ' 03 © CO CO I *o CO I 42 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN R. 14 E. R. 15 E. R. 16 E. R.17 E. -0.9- Isogram Shows concentration of iron. Line approxi¬ mately located; interval 0.6 ppm More than 2.1 ppm of iron # 1.60 Water well Number is iron, in parts per million Figure 9.—Distribution of iron in ground water in the sandstone aquifer, Winnebago County. GROUND WATER 43 R.17 E. Base from State Highway Commission roadmap EXPLANATION -400- Isogram Shows total dissolved solids. Line approximately lo¬ cated; interval 200 ppm # 370 Water well Number is dissolved solids, in parts per million Figure 10.—Distribution of dissolved solids in ground water in the sandstone aquifer, Winnebago County. 44 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN R. 14 E. R. 15 E. R 16 E. R. 17 E. EXPLANATION - IOO - # 265 Isogram Water well Shows concentration of sul- Number is sulfate, in parts fate. Line approximately per million located; interval 100 ppm Figure 11.— Distribution of sulfate in ground water in the sandstone aquifer, Winnebago County. AVAILABILITY AND USE OF WATER Winnebago County has abundant and readily available supplies of ground and surface water for nearly all anticipated uses. The supplies are not uniformly available in all areas, however, and may vary with time and man’s use. The availability of surface water is dependent upon the storage of water in the Lake Winnebago Pool, the inflow to the pool from the Wolf and upper Fox Rivers, and the outflow of the pool to the lower AVAILABILITY AND USE OF WATER 45 Fox River. The greatest inflow to the pool is from the Wolf River; measured at New London, the inflow is about 1,200 cfs (cubic feet per second) during 50 percent or more of the time (fig. 12). The Fox River contributes about 840 cfs (measured at Berlin) during 50 percent or more of the time (fig. 12). The outflow from the pool, measured at the Rapide Croche Dam on the lower Fox River, is about 3,750 cfs during 50 percent or more of the time (fig. 12). Assuming that the flow of the Fox River at Rapide Croche Dam for the period 1918—54 is representative of the long-term flow, the flow-duration curve can be used to estimate the future availability of water from the Lake Winnebago Pool. For example, discharge from the pool, measured at Rapide Croche Dam, equaled or exceeded about 1,200 cfs during 95 percent of the time. Surface water is not readily available in areas distant from the Lake Winnebago Pool because of the scarcity of lakes and the small flow of streams. Estimated quantities of ground water available to wells in Winne¬ bago County range from about 10 gpm to about 1,000 gpm (fig. 13). In places where the sand and gravel layers in the drift aquifer are thick, the sand and gravel generally yield as much as 50 gpm to wells. PERCENT OF TIME INDICATED DISCHARGE WAS EQUALED OR EXCEEDED EXPLANATION O--O---O o-O-0-o Outflow from Lake Winnebago Pool Inflow to Lake Winnebago Pool Figure 12.— Duration curves of daily flow of major streams flowing into and out of the Lake Winnebago Pool. 46 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN The Platteville-Galena unit also yields as much as 50 gpm, but the yields may be greater in areas where the dolomite is highly fractured. The sandstone aquifer probably yields as much as 1,000 gpm to fully- penetrating wells in places where the aquifer is of sufficient thickness. The total use of water in Winnebago County from both surface- and ground-water sources was estimated to be 53.6 mgd in 1962. Sur¬ face water from Lake Winnebago and the Fox River supplied the domestic needs of about 72 percent of the people in Winnebago County and provided an estimated 77 percent of the water used for all pur¬ poses. Ground water supplied the remaining 23 percent of the total water used in the county; however, because of its county wide avail¬ ability, it is the principal source of water to communities other than Neenah, Menasha, and Oshkosh, to many industries, and for rural domestic and stock use. A summary of the estimated use of surface water in 1962 for various purposes in municipal areas and in the remainder of the county is shown in table 6. The two largest users are the municipal powerplant of Menasha, which diverts large quantities of water for cooling pur¬ poses, and the combined pulp and paper industry in Neenah and Menasha, which uses water for processing, cooling and air condition¬ ing, and sanitary purposes. Municipal supply for Neenah, Menasha, and Oshkosh, the three principal cities in the county, is the third largest user of surface water. The municipal use of water in Neenah, Menasha, and Oshkosh has increased from about 7.5 mgd in 1950 to 11.3 mgd in 1960 because of increased population and an increased use of municipal water by in¬ dustries. If municipal pumpage increases at the same rate, it will amount to about 27 mgd by the year 2000. Most of the large quantities of water pumped out of Lake Winne¬ bago and the Fox River for municipal and industrial use is returned to the surface-water bodies, but with some alteration of chemical quality and an increase in temperature. The temperature of dis¬ charged surface water used for cooling purposes by the powerplant at Menasha is raised as much as 18 °F, depending on the time of year. Surface water pumped for municipal use is returned as treated sewage effluent. Water used by the pulp and paper industry also is returned to the Fox River as treated effluent. The average daily use of ground water for all purposes in Winne¬ bago County in 1962 is estimated at about 9 mgd (table 6). Ground water is used for public supply in the city of Omro, the village of Winneconne, the Winnebago State and County Hospitals, all rural schools and churches, and a shopping center. Industrial use of ground water includes condenser cooling, washing and processing, boiler use, I AVAILABILITY AND USE OF WATER 47 R. 14 E. R 15 E. R 16 E. R. 17 E. Base from State Highway Commission roadmap 0 1 2 3 4 MILES I_l_I_l_i EXPLANATION Gallons per minute 0-50 Adequate for domestic and stock use 51-500 Adequate for small urban development and light industry 501-1000 Adequate for munici¬ pal use and heavy industry Figure 13.—Estimated availability of ground water, Winnebago County. brewing, and air conditioning. The largest user of ground water in the county is the pulp and paper industry. Ground water is used for rural domestic and stock-watering purposes and a small amount is used for lawn irrigation by several golf courses and cemeteries. The greatest use of ground water is in Neenah and Menasha with a total pumpage of nearly 4 mgd in 1962, or about 44 percent of the total estimated amount used in the county. The use of ground water in Oshkosh was about 0.9 mgd, or about 10 percent of the total ground water used in the county. 48 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN Table 6. —Estimated average daily use of water in Winnebago County, 1962 [Excludes power generation] Amount of use by area (mgd) Total Type of use Neenah Mena- sha Oshkosh Omro Winne¬ conne Other use Public supply Municipal: Ground water_ _ 0.0 0.0 0.0 0.2 0.1 0.0 0.3 Surface water_ _... .. . 3.5 4.6 4.2 .0 .0 .0 12.3 Other: Ground water__ .0 .0 .0 .0 .0 .4 .4 Surface water.. _ .0 .0 .0 .0 .0 .0 .0 Total public supply_ .. 3.5 4.6 4.2 .2 .1 .4 13.0 Industrial Pulp and paper manufacture: Ground water_ . 2.1 1.2 .0 .0 .0 .0 3.3 Surface water__ ... __ 9.9 7.8 .0 .0 .0 .0 17.7 Other manufacturing: Groundwater... .. . __ .0 .0 .5 .0 .0 .3 .8 Surface water..... .1 .1 .1 .0 .0 .0 .3 Dairy products processing: Groundwater.. _ . .4 .0 .1 .1 .2 .3 1.1 Food processing: Groundwater. __ . .0 .0 .0 .0 .0 .1 .1 Brewing and malting: Ground water__ .0 .0 .2 .0 .0 .0 .2 Air conditioning: Groundwater_ ___ .2 .0 .1 .0 .0 .0 .3 Cooling in electrical power produc¬ tion: Surface water_... _ .0 14.4 .0 .0 .0 .0 14.4 Total industrial.._ .. 12.7 23.5 1.0 .1 .2 .7 38.2 Rural Domestic (total nonurban use): Ground water___ Farm livestock: Ground water.... Total rural. Total use... 1.4 1.0 2.4 53.6 Over the period 1953 to 1962, for which some pumpage records are available, the industrial use of ground water increased only slightly both in the county and in the Neenah-Menasha and Oshkosh areas. The muncipal use of ground water by the city of Omro and the village of Winneconne increased by about 30 percent and 230 percent, respec¬ tively, over the same period. Population figures indicate an increase of about 19.5 percent in the rural population between 1950 and 1960 (U.S. Dept. Commerce, 1960). Rural use of ground w^ater probably increased a corresponding amount during this period. The amount of water lost by consumptive use, principally by evap¬ oration, in Winnebago County is difficult to determine because of the many contributing factors. However, the following estimates of con¬ sumptive use generally can be applied for planning purposes. About 10 percent of the water pumped for municipal supply is lost by evap- PRESENT AND ANTICIPATED WATER PROBLEMS 49 oration from steam boilers, lawn irrigation, and other miscellaneous uses (Wirth, 1959, p. 33). Water withdrawn for all industrial con¬ sumptive uses is about 2 percent (MacKichan and Kammerer, 1961, p. 17). Consumptive use of water by the pulp and paper industry is estimated at only about 1 percent (Wirth, 1959, p. 33). The recreational use of the extensive lakes and rivers in Winnebago County cannot be overlooked because of its importance to local resi¬ dents and to tourists, but a detailed analysis of such use is beyond the scope of this report. Quantitative data and recommendations for recreational use of water in Winnebago County are available from the Wisconsin Department of Resource Development. PRESENT AND ANTICIPATED WATER PROBLEMS Water problems in any area generally can be listed under the fol¬ lowing headings: (1) Supply in relation to demand, (2) distribution, (3) natural quality, (4) manmade pollution, (5) variability, and (6) floods. Consideration of these problems in Winnebago County is given in the following discussion. SUPPLY IN RELATION TO DEMAND Winnebago County is fortunate in having an abundant supply of both ground and surface water. Total recharge to the ground-water reservoirs greatly exceeds local pumpage throughout the county, even during periods of scanty rainfall. If pumpage increases at a normal rate in the future, there is little danger of seriously depleting the ground-water supply for a long period of time. A problem of declin¬ ing water levels in wells may arise in local areas of high demand if well spacing is inadequate. Interference between closely spaced wells could seriously reduce the efficiency of individual wells. Surface water in the county also greatly exceeds the amount pres¬ ently used. Although streamflow may be seriously diminished during periods of drought, water is retained in the county by storage in the Lake Winnebago Pool, and part of this water is available for use. The generally nonconsumptive uses of surface water also permit the water to be reused for other purposes. If surface-water use increases at a normal rate, a shortage of supply is not anticipated in the near future, except possibly during periods of severe drought. DISTRIBUTION Ground and surface water are fairly well distributed throughout Winnebago County, and for most of the area major distribtuion prob¬ lems do not exist and are not expected to arise in the near future. 50 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN Numerous lakes and streams make surface water readily available over about two-thirds of the county, and extensive aquifers make ground water available over most of the county. However, surface water is not readily available from about one-third of the county. The sandstone aquifer is fairly thin, and only small to moderate quanti¬ ties of water are available in the preglacial buried channels in the northwestern part of the county and in the upper Fox River valley (pi-1)- NATURAL QUALITY The principal water-quality problems in Winnebago County are algae and hardness in surface water and iron, hardness, and salinity in ground water. Growth of algae in the shallow Lake Winnebago Pool during the summer creates serious aesthetic and treatment problems. Hardness is generally only a minor problem, but for some uses the water must be treated. Dissolved iron in ground water occurs over a large part of the county, and saline ground water occurs on the eastern side of the county. However, the water still is usable for many purposes, and treatment can make the water usable for almost all purposes. Pump¬ ing at Neenah-Menasha, the Winnebago State and County Hospitals, and Oshkosh has locally reversed the natural moA^ement of ground water. This westward movement of water has created the possibility that highly mineralized water from the saline-water zone may move toward the areas of pumping and eventually may contaminate the sandstone aquifer locally. The sulfate content in ground water apparently has increased grad¬ ually since before 1934 in wells in the city of Neenah, and also has in¬ creased since 1957 in wells at the Winnebago State Hospital (table 7). This increase may be related to a westward migration of saline water because of pumping. However, additional analyses are needed over a period of time to prove this conclusion. Other constituents in ground water in these pumping areas and at Oshkosh remained constant during the same period (table 7). MANMADE POLLUTION Pollution of surface water in Winnebago County is a minor and lo¬ cal problem at present, but may be expected to increase in the future. Streamflow generally is sufficient to dilute sewage and industrial wastes that are discharged into the Fox and Wolf Rivers before they enter the county, and to dilute wastes that are discharged to the Lake Winnebago Pool within the county. Sewage and other organic wastes PRESENT AND ANTICIPATED WATER PROBLEMS 51 Table 7. —Chemical analyses of ground water at Neenah, Oshkosh, and the Winnebago State Hospital showing changes in chemical quality [All values in parts per million] Well Owner Date of collec¬ tion Iron (Fe) Bicar¬ bonate (HC0 3 ) Sul¬ fate (S0 4 ) Chlor¬ ide (Cl) Dis¬ solved solids Hard¬ ness as CaCC >3 Wi-20/17/27-28_ City of Neenah_ _ Pre-1934 2.2 305 892 11 1,639 940 20/17/28-59_ Galloway Milk Co., 1963 1.0 277 956 8 lj 380 1,751 Neenah. Unknown_ Peoples Brewing Co., Pre-1934 1.0 331 319 Oshkosh. Wi-18/16/25-41_ _do.. ... . .. 1955 .02 307 109 19 412 467 Unknown_ Rockwell Standard Corp., Pre-1934 2.4 280 254 Oshkosh. Wi-18/16/14-356 _do_ _ . 1962 .9 176 220 19/17/31-37. . Winnebago State Hos- 1957 .9 370 268 964 645 pital. ..do_ ... 1958 .9 273 608 .do. 1961 266 330 740 600 19/17/31-39. .do. . . 1957 .9 236 310 1,002 674 do. 1958 .7 297 540 .do. 1963 1.6 222 375 910 670 discharged to streams consume oxygen and provide nutrients which promote the growth of algae. Chemical wastes discharged to streams may locally render the water unsuitable for ordinary uses. Expand¬ ing industries and cities with inadequate and overtaxed sewage and waste-disposal systems should take care not to pollute surface water in the Fox and Wolf River basins. Pollution of ground water is a potential problem in areas of Winne¬ bago County where dolomite of the Platteville-Galena unit or of the Prairie du Chien Group crops out or is overlain by only a thin layer of unconsolidated deposits. Because ground water moves through solu- tionally enlarged joints, fractures, bedding planes, and other large openings in dolomite, there is very little purification of water in the formation. Impurities introduced into the formation, may be carried for long distances and pollute large areas. Flushing of a polluted aquifer requires a great length of time before the ground water is usable. Polluted water from a defective private sewage system in a dolomite area could enter shallow wells that are open in the formation. Dump¬ ing of rubbish and industrial wastes in dolomite quarries or highly permeable sand and gravel pits overlying dolomite also is a potential cause of ground-water pollution in shallow wells. A potential ground-water pollution problem exists in a large area of the Lake Winnebago drainage area (p. 28), especially near Neenah- Menasha. The area is underlain by dolomite of the Platteville-Galena unit (pi. 1) and the glacial drift is thin over a large part of the area (fig. 4). The potential for pollution would be increased in this area by development that did not include proper methods of waste treat¬ ment and disposal. A potential pollution problem also exists along the UfliyfcRSITY OF HUNCH L!RPA r)V 52 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN escarpment of the Prairie du Chien Group in the western and central parts of the county (pi. 1, fig. 4). Casing off all or a large part of the dolomite and drilling into under¬ lying sandstone is the best method to prevent polluted water from entering wells in the dolomite areas. Well owners also should have their well water checked periodically for bacteriological content to insure that the aquifer has not become polluted. Sand and gravel layers and lenses in the drift aquifer generally are not subject to pollution, because in most places they are overlain by thick deposits of clay and silt. However, if these sand and gravel lay¬ ers occur near, or crop out at, the land surface, they are susceptible to pollution as a result of improper waste treatment and disposal. Pollutants introduced into a sand and gravel layer generally travel only short distances before they are filtered out, but wells close to the source of pollution may become polluted. Salt used on roads and man¬ made organic compounds, such as gasoline or pesticides, may travel much greater distances because they do not break down readily and are not filtered out by the aquifer. This type of pollution has not been reported, but these pollutants can be carried into the drift aqui¬ fer and make the water unusable for long periods of time. The presence of detergent or ABS (alkyl benzene sulfonate) in ground water has not been reported and does not appear to be a cur¬ rent problem in Winnebago County. The source of ABS in ground water generally is from private sewage systems. It is recommended that ABS in drinking water should be limited to 0.5 ppm because higher concentrations may cause undesirable taste and foaming (U.S. Public Health Service, 1962, p. 24). The presence of ABS in water from a well indicates that the water may contain other harmful pollut¬ ants from sewage systems. The presence of ABS in water may be in¬ dicated by foaming when a sample of water is shaken in a small bottle. Pollution of ground water in the sandstones of Cambrian and Ordo¬ vician ages is unlikely because of the filtering properties of sandstone and the thickness of overlying material through which recharge must travel to reach the artesian aquifer. Pollutants may enter the sand¬ stone through wells that are inadequately sealed at the surface or through dolomite that is exposed or near the surface. VARIABILITY * Variability refers to the changes that can occur in the county in the amount of streamflow and the amount of ground water in storage. Generally, variability is not a problem in Winnebago County because of the control on the surface water (Lake Winnebago Pool) and the large amount of water available from the ground-water reservoirs. DEVELOPMENT OF WATER RESOURCES 53 FLOODS Flooding is not a major problem in Winnebago County because of the reservoir control and storage of the Lake Winnebago Pool. Flood¬ ing of minor streams is not a current problem because of the low density of population and agricultural use of land. SUGGESTIONS FOR DEVELOPMENT OF WATER RESOURCES In the next several decades an expanding economy will place greater demands on the water resources of Winnebago County. Because this expanding economy depends on the availability of large supplies of good-quality water, the water resources of the county should be devel¬ oped in an orderly and efficient manner. To choose the best possible method of developing and using water, water managers need to formu¬ late comprehensive plans for use and management of ground and sur¬ face water and to consider the effects of water development on all aspects of the local economy. The following suggested methods of development may be useful to water managers in the county for planning purposes. GROUND-WATER DEVELOPMENT Ground-water development in Winnebago County is expanding and is expected to continue expanding in the future. This development will be influenced by surface-water use, by distance of water transpor¬ tation, by relative costs, and by water quality. In developing a ground-water supply, water levels decline around a center of pumping, and pumping lifts are increased. The greatest decline in water levels would be in areas where heavily pumped wells are very closely spaced. A good development plan should have wells spaced at distances that will minimize increased pumping lifts due to well interference without overly increasing the costs of connecting or transmitting lines. Consequently, estimates of well discharged, well spacing, and pumping lifts should be made when selecting new well sites. The 'well discharge for a new well generally may be estimated from the specific-capacty data for other wells in the area. Before a new well is drilled in an area where little or no information on the aquifer is available, a test well should be drilled and pumped to determine yield. Estimation of the optimum spacing between a new well and existing well or between wells in a new well field should be based on computa¬ tion of well interference for different well spacings for an assumed pe¬ riod and rate of pumping. Such estimates may be made from the Theis nonequilibrium formula, the coefficients of transmissibility and storage 54 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN for the aquifer being determined by aquifer tests or other methods. Such computations for wells tapping the sandstone aquifer in eastern Winnebago County are shown by figures 14 and 15. These curves show the amount of interference that will occur in 1 month, 1 year, and 5 years at 100 to 20,000 feet from a well pumping continuously at a rate of 500 gpm (fig. 14) and the interference that will occur at any time between 10 and 4,000 days at 1,000,10,000, and 20,000 feet from a well pumping continuously at rate of 500 gpm (fig. 15). For example, the drawdown in a well spaced 1,000 feet from another well pumping at a rate of 500 gpm for 30 days would be about 20 feet, whereas the drawdown in a well spaced 10,000 feet from the pumping well would be about 6 feet (fig. 14). After 2,000 days, or about 5!/2 years of pumping, drawdown in the well spaced at 1,000 feet would be about 33 feet compared to about 18 feet in a well spaced at 10,000 feet from the pumped well. Water-level declines for any rate of pumping can be determined from the curves by the direct proportionality of drawdown to the rate of pumping. For example, if the rate of pumping is 300 gpm instead of 500 gpm, water-level decline will be 0.6 of that shown on the curve. The interference that will occur from more than one pumping well is the sum of the interference of all wells. In most places in Winnebago County, the beds confining water in the sandstone aquifer only impede or retard the vertical movement of water; water in the confining beds, in the overlying alluvium, and from surface water moves downward in response to the lowered piezometric head around a pumping well. Although the rate of movement of this water, called vertical leakage, is probably small, large quantities of water may be contributed to the aquifer over a long period of time. More work is required to determine the amount of water that is con¬ tributed to the aquifer by leakage. The curves in figures 14 and 15 are based on the assumption that all water pumped is withdrawn from storage and are not adjusted for recharge to the aquifer. The draw¬ downs shown by the curves are greater than those which actually would occur. Additional wells in the Neenah-Menasha and Oshkosh areas should be located as far as feasible from the center of the cones of depression beneath the cities to reduce interference from other pumping wells. Because recharge to the cones of depression is greatest from the west at Neenah-Menasha and from the west and southwest at Oshkosh (pi. 4), dispersal of wells in these directions would be more effective in reducing water-level declines than dispersal in any other direction. Locating wells close to surface-water bodies might induce recharge and reduce water-level declines. Periodic water-level measurements in wells tapping the sandstone DEVELOPMENT OF WATER RESOURCES 55 aquifer, especially in the Neenah-Menasha and Oshkosh areas, are necessary for determining water-level trends and predicting the decline of water level that will result from additional development. All punipage from high-capacity wells should be metered and correlated with changes in water levels. Because highly mineralized water may be moving toward the centers of pumping on the eastern edge of the county, new sandstone-aquifer wells should be located as far to the west as is practical, to decrease the possibility of tapping this saline water. The quality of water from wells in this area should be monitored to detect saline-water migration. If there is a migration of saline water, the monitoring program would aid in its control. SUPPLEMENTAL USE OF GROUND WATER WITH SURFACE WATER Surface water is used extensively in Winnebago County for municipal and industrial purposes, and the present supply is far in excess of demand. Surface water is an excellent source of supply during most of the year; however, it is not readily available in all parts of the county, and high water temperatures and the growth of algae are inherent problems during the summer months. A possible method of helping to alleviate these problems, especially during the summer months, is the supplemental use of ground water from a network of adequately spaced wells. Ground water generally does not need the expensive treatment required for surface water. The supplemental use of ground water would reduce the amount of treatment required for algae and would lower the temperature of water. Comparison of costs of installation, operation, and maintenance of a surface-water system with costs of a ground-water system is beyond the scope of this report, but the various factors should be evaluated to determine the most economical system to use. Generally, installa¬ tion costs for a ground-water system are considerably less than for a surface-water system, but other costs may be comparable. Con¬ sidering costs, the year round supplementing of present surface-water facilities with ground water should be considered as a means of ex¬ panding present municipal water-supply systems. Emergency supplies of water can be obtained from ground-water systems in the event of a natural or manmade disaster, whereby surface- water sources might become unusable. The ground-water supplies should be safe, at least for the period of time needed for decontamina¬ tion of surface water. Existing high-capacity wells in Winnebago County, a large percentage of which are shown on plate 1, should pro¬ vide adequate water for emergency use. A ground-water system sup¬ plementing a municipal surface-water supply also would provide an emergency source of water. GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN o CM 00 lO CM O i-H 00 CO CM O O o o o o cm co ^ in LlI $ Q LlI 0 . D 0. o a: Li. I- LlI LlI U. CO Q 2 < CO D O I Ui o z < t- CO Q 133d Nl ‘( s )NMOaMVda Figure 14.—Theoretical distance-drawdown curves for an infinite aquifer, based on coefficients of transmissibility and storage determined for the sandstone aquifer at the Winnebago State and County Hospitals. DEVELOPMENT OF WATER RESOURCES 133j n i '(») NMoaMvaa Figure 15.—Theoretical time-drawdown curves for an infinite aquifer, based on coefficient of transmissibility and storage determined for the sandstone aquifer at the Winnebago State and County Hospitals. 58 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN LAKE MICHIGAN AS A SOURCE OF SUPPLY Water from Lake Michigan, about 45 miles east of Neenah-Menasha, could be transported into Winnebago County by pipeline and would provide an abundant water supply for many years. Water from Lake Michigan is colder and less mineralized than water from the Fox River and algae are not a serious problem. Although developing and trans¬ porting Lake Michigan water to this area would be costly, such a development might be economical if a sufficient number of communities and industries were included in the system. Because of the high cost of development, local sources of surface and ground water should be carefully evaluated before Lake Michigan is considered as a source of supply. CONCLUSIONS AND RECOMMENDATIONS Winnebago County has generally good quality ground water and surface water available over most of its area and in quantities that will not limit forseeable development. Water from the Lake Winnebago Pool, which has a storage capacity of 25 billion cubic feet and an aver¬ age discharge of about 4,190 cfs, is hard, is locally polluted, contains algae during the summer months, and requires treatment, but gen¬ erally it is suitable for municipal and most industrial uses. Water from the pool ranges in temperature from 32° to 80° F annually. The sandstone aquifer, present throughout the county, is a depend¬ able source of water for municipal, industrial, and domestic uses. Yields up to 1,000 gpm may be obtained from fully penetrating wells in the eastern and southern parts of the county where the sandstone has a maximum thickness of about 600 feet. The aquifer is confined under artesian pressure by the overlying Platteville-Galena unit and glacial drift. Water from the sandstone aquifer is hard to very hard and contains iron in some places. A saline-water zone, containing dissolved solids in excess of 1,700 ppm and sulfate in excess of 900 ppm, is present on the eastern edge of the county. Mineralization in this zone increases from west to east. In the remainder of the county, water from the sandstone aquifer is of good quality, generally contain¬ ing 200 to 400 ppm dissolved solids. Temperature of the water ranges from 49° to 54° F. The Platteville-Galena unit, present, in the eastern and southern parts of the county, yields as much as 50 gpm to wells and is a depend¬ able source of water for domestic and farm uses. The water is hard to very hard but otherwise is of good quality. Pollution is a potential problem because of the poor filtration properties of dolomite and be¬ cause the unit crops out at the land surface. CONCLUSIONS AND RECOMMENDATIONS 59 A drift-filled preglacial bedrock channel, having a maximum depth of about 300 feet, extends from Waupaca County through the north¬ western corner of Winnebago County and into Waushara County, and underlies the Wolf River and Lake Poygan. A preglacial chan¬ nel also underlies the upper Fox River in Winnebago County. Uncon¬ solidated layers and lenses of sand and gravel in these preglacial channels yield as much as 50 gpm to wells and are dependable aquifers for domestic and farm use. These deposits are confined by clay till and are not subject to pollution. Water from the sand and gravel deposits is generally of good quality and is less mineralized than water from the underlying sandstone aquifer. The quality and temperature of the water remain nearly constant, the temperature ranging from 49° to 54° F. The total estimated use of water in the county in 1962 was 53.6 mgd, of which 44.7 mgd was supplied from the Lake Winnebago Pool and 8.9 mgd from ground-water sources. Although more surface water than ground water is used in the county, ground water is the principal source of supply for communities other than Neenah, Menasha, and Oshkosh, for many industries, and for all rural domestic and stock use. Industry is the largest user of surface and ground water in the county. The area of greatest use of ground water in 1962 was Neenah- Menasha, having an estimated annual pumpage of 1.4 billion gallons (3.8 mgd). Pumpage in the Oshkosh area was estimated at 0.5 bil¬ lion gallons per year (1.4 mgd). Only about 10 percent of the water used for municipal purposes and 1 to 2 percent of the water used for industrial purposes was used consumptively, the remainder being returned to the Lake Winnebago Pool and the lower Fox River. Pumping of water from the sandstone aquifer has lowered water levels 110 to 120 feet in Neenah-Menasha and 25 to 30 feet in Oshkosh below the reported levels in 1915. Water levels in the remainder of the county are at about the same level as those reported in 1915. The piezometric surface of the sandstone aquifer indicates that ground water is moving toward the Wolf and Fox Rivers and Lake Winne¬ bago from ground-water divides which generally coincide with topo¬ graphic divides formed by escarpments of the Prairie du Chien Group and Plateville-Galena unit. Present water problems in the county include the growth of algae and local pollution in the Lake Winnebago Pool, iron in water from the sandstone aquifer over a large part of the county, and saline ground water along the eastern edge of the county. Potential water problems include rapid decline of water levels of interference between closely spaced wells, migration of saline ground water to areas of pumpage 60 GEOLOGY AND WATER, WINNEBAGO COUNTY, WISCONSIN in the eastern part of the county, surface-water pollution from inade¬ quately treated sewage and industrial wastes, and pollution of ground water in dolomite aquifers. Development of the water resources of the county should follow a comprehensive plan which takes into consideration all aspects of water use. The use of ground water to supplement present surface- water supplies would be a fairly inexpensive method to expand water supply at Neenah-Menasha and Oshkosh and to reduce the algae- treatment problems during the summer months. Existing wells and proposed supplementary ground-water supplies would provide ade¬ quate emergency sources of water. In the Neenah-Menasha and Osh¬ kosh areas, dispersal of wells toward the west, which is the direction of greatest recharge, would be more effective in reducing water-level declines than dispersal in any other direction and would also decrease the possibility of tapping saline water in the sandstone aquifer. A program of monitoring ground-water levels, pumpage, and quality of water in the Neenah-Menasha area is necessary to insure proper development of the ground-water resources. An abundant supply of good quality water could be obtained from Lake Michigan by pipeline, but the cost of such an installation prob¬ ably would require the cooperative use of the water by a number of communities and industries. REFERENCES « Alden, W. C., 1918, The Quaternary geology of southeastern Wisconsin, with a chapter on the older rock formations: U.S. Geol. Survey Prof. Paper 106, 356 p. Bean, E. F., 1949, Geologic map of Wisconsin: Wisconsin Geol. and Nat. History Survey. Berkstresser, C. F., Jr., 1964, Ground-water resources of Waupaca County, Wis¬ consin : U.S. Geol. Survey Water-Supply Paper 1669-U, 38 p. Birge, E. A., and Juday, C., 1911, The inland lakes of Wisconsin: Wisconsin Geol. and Nat. History Survey Bull. 22, 259 p. Drescher, W. J., 1953, Ground-water conditions in artesian aquifers in Brown County, Wisconsin: U.S. Geol. Survey Water-Supply Paper 1190, 49 p. Ferris, J. G., Knowles, D. B., Brown, R. H., and Stallman, R. W., 1962, Theory of aquifer tests: U.S. Geol. Survey Water-Supply Paper 1536-E, 174 p. Knowles, D. B., 1964, Ground-water conditions in the Green Bay area, Wiscon¬ sin, 1950-60 : U.S. Geol. Survey Water-Supply Paper 1669-J, 37 p. Knowles, D. B., Dreher, F. C., and Whetstone, G. W., 1964, Water resources of the Green Bay area, Wisconsin: U.S. Geol. Survey Water-Supply Paper 1499-G, 67 p. LeRoux, E. F., 1957, Geology and ground-water resources of Outagamie County, Wisconsin: U.S. Geol. Survey Water-Supply Paper 1421, 57 p. MacKichan, K. A., and Kammerer, J. C., 1961, Estimated use of water in the United States : U.S. Geol. Survey Circ. 456, 44 p. REFERENCES 61 Newport, T. G., 1962, Geology and ground-water resources of Fond du Lac County, Wisconsin: U.S. Geol. Survey Water-Supply Paper 1604, 52 p. lyling, R. W., 1961, A preliminary study of the distribution of saline water in the bedrock aquifers of eastern Wisconsin: Wisconsin Geol. and Nat. History Survey Inf. Circ. 5, 23 p. Smith, L. S., 1908, The water powers of Wisconsin: Wisconsin Geol. and Nat. History Survey Bull. 20, 354 p. Summers, W. K., 1965, Geology and ground-water resources of Waushara County, Wisconsin: U.S. Geol. Survey Water-Supply Paper 1809-B, 32 p. Theis, C. V., 1935, The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using ground-water storage: Am. Geophys. Union Trans., pt. 2, p. 519-524. Thwaites, F. T., 1943, Pleistocene of part of northeastern Wisconsin: Geol. Soc. American Bull., v. 54, p. 87-144. -1957, Buried Precambrian of Wisconsin : Wisconsin Geol. and Nat. History Survey map. J.S. Army Corps of Engineers, 1922, Survey of Fox River: U.S. 67th Cong., 2d sess., House Doc. 146, 170 p. J.S. Department of Commerce, 1960, 1960 Census of population, Wisconsin: U.S. Dept. Commerce Bur. Census, Advance Rept, PC(A1)-51, 19 p. J.S. Public Health Service, 1962, Drinking water standards, 1962: U.S. Public Health Service Pub. 956, 61 p. kVeidman, Samuel, and Schultz, H. R., 1915, The underground and surface water supplies of Wisconsin: Wisconsin Geol. and Nat. History Survey Bull. 35, 664 p. iVirth, H. E., 1959, Water use in Wisconsin: Wisconsin State Board of Health, 36 p. Wisconsin Conservation Department, 1962, Winnebago County wetlands: Wis¬ consin Conserv. Dept., Wisconsin Wetland Inventory, 70 p. Wisconsin Committee on Water Pollution, 1956, Evaluation of stream loading and purification capacity: Wisconsin Comm, on Water Pollution Bull. 101, 110 p. o - - s m * WATER-SUPPLY PAPER 1814 PLATE 1 551 . 4 ? oi, 1 St Jofinsr/V Clovis Park 5 £5A S 667 *N. Towers, Ligfithouse Reef Oh Outer Bar !adio Towers 4 (WNAM) g ' UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY PREPARED IN COOPERATION WITH THE UNIVERSITY OF WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY WATER-SUPPLY PAPER 1814 PLATE 1 651 49 01 l q OUTAGAMIE CO WAUPA> Medina Junction Clovis P»rk Gravel .P/ti Road Sch DOTY o 784 JU&Tlfi' 'V/TI'ii/oiA Ba 11 _V Nefnah & L,«hT 11 0/ 'Neenah Pblnt (Davis Point ,SUnri»e Bay • % -v <_5 t JJiifi2#'Whedler Point Rainbow Beach i IClarks Point ■jtftfManaur Bay i 739^"--J J t l 2 / I /Adella) Beach / U uUBUAlO£ ' KevsHcK Reel Piacenza^ ISO Indian Sho Ij'Slevens Reel Gre^nlown M Ricker Bay Wrnnecdnne' 'Jenkyns Point i Nevitt Point "biennis Miiirt^Acres rk|ns Point land Park imer Point's ( "Falrveiw' Beach l Radio Towew4 7/ yf 7 \ T19N Shangri La Point - ieenville luhehmoor Sunset Pyfntjj ^V666'&, 592 Highland Shore 6 00" _-— §50’ veonarda Point Rockaway, JJeach jOakwooti iOmro - ^ cjk)^oojr l 7| ■ ^ " ' '\ GraveTPit 'Brays Point 1,66.351 731 Oshkosh Reels /rOMRO i irviile Sch533 ; I 766 Point .Paukotuk mint Oea ’fi"! t m, ' 9 Lo°- illlh.-k Wolf J*i. Vowfers, .'ey Outer Bar lM74a^^ Wheeler Point y' Rainbow Beach UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY PREPARED IN COOPERATION WITH THE UNIVERSITY OF WISCONSIN GEOLOGICAL AND NATURAL HISTORY SURVEY 3 )' T / 0 A 1 q WATER-SUPPLY PAPER 1814 PLATE 4 88° 25' 88°50''R. 14 E Base compiled from U.S. Geological Survey topographic maps fond DU LAC CO r 17 £ puna i»u uni w 88*25' NTERIOR—GEOLOGICAL SURVEY WASHINGTON D C — I 966-W8S1 8 I Hydrology by Perry G. Olcott. 1963 MAP SHOWING CONTOURS ON THE PIEZOMETRIC SURFACE OF THE SANDSTONE AQUIFER IN WINNEBAGO COUNTY, WISCONSIN, JULY 29-AUGUST 4, 1963 mmm . .. I • '1 I I IW M IW MV ■ ’ * - m i l » ■ . —MM MMk