The approximate shape of the water table in the part of the Neosho river valley here considered is shown by the water-table contours in plate 2. As a basis for constructing this map, the altitude of the water table was determined instrumentally at some of the 29 test holes and at 18 hand-auger holes and wells. The locations and altitudes of the drill holes, auger holes, and wells are given in table 5. The water surface of Neosho river and its local tributaries was determined in part instrumentally and in part from maps of the Neosho river valley prepared by the Engineer Corps of the U.S. Army.
The water table intersects the land surface in some parts of the valley, as indicated by the ponds and small streams shown in plate 2. In other parts of the valley the water table ranges from less than 1 foot to 13 feet below the land surface (table 5). In most parts of the valley the water table is less than 10 feet below land surface, but it is somewhat deeper than 10 feet in those parts of the area immediately adjacent to Neosho river.
Table 5--Locations, altitudes, and water levels in wells and test holes. Ssurce of data: A, test hole drilled by hand auger; R, test hole drilled by hydraulic-rotary method; W, water well.
|T. 31 S., R. 21 E.|
|1||SE SE SW sec. 23||A||837.1||2.3|
|2||NE NW NW sec. 26||A||831.9||1.0|
|3||NE NE sec. 27||A||831.7||2.3|
|4||NW corner NE NE sec. 27||R||832.1||2.7|
|5||NW corner NE NE sec. 27||W||831.6||2.2|
|6||NW corner NE sec. 27||R||830.6||2.7|
|7||NE NW sec. 27||R||832.1|
|8||NE NW sec. 27||W||833.4||7.8|
|9||SE corner SW SW sec. 27||R||831.9|
|10||SW SE SW sec. 27||A||832.0||3.4|
|11||SW corner SE sec. 27||R||830.8||2.2|
|12||SE sec. 28||R||827.2|
|13||NE corner sec. 33||R||831.5|
|14||NE sec. 33||R||829.6|
|15||NE sec. 33||R||830.4|
|16||NE sec. 33||W||832.0||8.3|
|17||NE sec. 33||R||828.1|
|18||NE sec. 33||R||829.7|
|19||NE sec. 33||R||814.8|
|20||NE sec. 33||R||813.9|
|21||NE sec. 33||R||818.0|
|22||NE sec. 33||R|
|23||NE sec. 33||R|
|24||NE corner sec. 34||R||829.1|
|25||NE NW NE sec. 34||A||830.7||2.1|
|26||NE corner NW sec. 34||R||832.1||6.2|
|27||SW corner NE sec. 34||A||827.1||2.9|
|28||NW SE SE sec. 34||W||827.9||2.9|
|29||NE NW sec. 35||R||828.4|
|30||NE NW sec. 35||A||828.0||4.7|
|31||NE NW sec. 35||R||828.0|
|T. 32 S., R. 21 E.|
|32||NE corner NW sec. 2||W||826.4||1.7|
|33||SE SE SW sec. 3||W||827.9||9.1|
|34||NW NW SE sec. 4||R||826.9|
|35||SE NW SE sec. 4||R||827.7||12.7|
|36||NE SE SW sec. 4||R||823.9||5.5|
|37||SW SE sec. 4||R||826.5|
|38||SW SE SE sec. 4||R||828.0||11.2|
|39||SE NW sec. 4||A||826.1||9.6|
|40||SW NW sec. 9||R||826.0||10.3|
|41||NE NW sec. 9||R||826.2||4.9|
|42||NE NW sec. 9||A||825.0||2.9|
|43||NW NE sec. 9||R||825.0|
|44||NE corner SW NE sec. 9.||A||825.3||5.8|
|45||NW corner SE NE sec. 9||R||825.6|
|46||SW corner NE sec. 9||A||825.5||3.7|
The water-table contours roughly parallel. the river and its tributaries and intersect the river at an acute angle upstream, indicating that the gradient of the water table is toward Neosho river in this area and that ground water eventually flows into it. The route may be indirect and circuitous, as in the northeastern part of the area, or direct, as near test hole 35. At times of high stage, however, the river probably returns some water to the underground reservoir near the course of the stream.
In some places the water table stands as much as 18 feet above river level. The average slope of the water table ranges from about 10 to about 20 feet to the mile. The gradient becomes progressively greater near the river and is small in some parts of the valley, as near test hole 20. These facts, together with the moderately low permeability of the aquifer, indicate that the movement of ground water under the natural conditions prevailing here is relatively slow. The several small ponds and meandering tributaries and the swampy conditions existing in parts of the valley also suggest slow movement of ground water, both laterally and vertically.
In the area contoured on the west side of the river in the southwestern part of the area, the ground water moves radially from high points on the water table near test holes 41 and 37 toward small tributary streams and Neosho river.
Yield of Wells
At present there are no wells in this part of the Neosho valley that yield large quantities of water. There are many small domestic and stock wells, the yields of which are sufficient to supply the small quantities required by the farmers and their families and by a few head of livestock at each farm. These wells supply as much water as is required of them but the quantity is not an index of the potential yield of the alluvium. Some residents of the area reported that their farm wells did not fail during the droughts that occurred between 1930 and 1940.
The test well, which is discussed at length above, was pumped at an average rate of 80 gallons a minute for the last 60 hours of the pumping test, during which time the water level in the pumped well declined 2.3 feet. The water level had not reached an equilibrium condition at the end of the 98-hour pumping test. These data are in part the basis for the conclusion that 50 gallons a minute is near the maximum rate at which a single well in the valley should be pumped continuously. Quantities greater than 50 gallons a minute, perhaps 100 gallons a minute, could be pumped from a single well only for short periods of time.
Quantity Available from Recharge
According to the U. S. Weather Bureau, the mean annual precipitation at Parsons is 40.63 inches; however, in 1941 the total precipitation was 53.92 inches, or 13.29 inches above normal. Neosho river overflowed its banks in June, August, September, and October, 1941. In October, 1941, the river was over its banks at Oswego for 21 consecutive days. A line marking the limit of overflow as mapped by the Engineer Corps, U. S. Army, is shown in plate 2 and that line approximately delimits the area underlain by alluvium. The sources of water available for recharge in this area are the precipitation that falls in the valley and flood waters of Neosho river derived from precipitation in the drainage basin.
The amount of water available for recharge from flood waters is difficult to determine and varies greatly from year to year. The percentage of the annual precipitation that percolates downward to the water table and recharges the ground-water reservoir is dependent on several factors. Some of these factors are the amount of annual rainfall, the physical character and the composition of the soil and subsoil, the proximity of the water table to the land surface, the condition of the soil before rainfall (i. e., moisture content, cultivation), and the number and depth of roots, animal burrows, and so forth.
The alluvial soils in the Neosho river valley have been classified as silty clay loam, silty clay, and clay (Drake, 1904, pp. 15-17; Knobel, von Treba and Higbee, 1926, pp. 14-16). These soils contain 15 to 45 percent clay, 40 to 65 percent silt, 5 to 15 percent very fine sand, and 2 to 5 percent fine sand. Constituents larger than fine sand (0.25 mm) are negligible. Descriptions of the surficial materials encountered in test drilling (see well logs) indicate that the soil is mostly silt and clay. The water table is close to the land surface and intersects it in places. The soils are of such composition that water percolates very slowly through them, but the proximity of the water table to the land surface tends to increase the amount of recharge, although in seasons of high precipitation some water may be rejected from an already full reservoir.
Many borings of the type made by some fresh-water crustaceans were observed in parts of the river valley both in March and in October, 1942. A pebble dropped into one of these holes can be heard to splash as it strikes the shallow water table. A great deal of water must reach the water table through openings of this kind, conceivably more than seeps through the clayey soil and subsoil.
In Kansas as a whole, the percentage of the annual precipitation that reaches the water table seems to range widely from probably less than 1 percent in parts of the High Plains to more than 25 percent in some areas (Lohman, S. W., 1941, p. 45). Although detailed study covering a year or more is necessary to determine the percentage of the annual precipitation that reaches the water table, it is probably safe to assume that at least 5 percent of the precipitation that falls in the Neosho valley recharges the underground reservoir. This assumed amount of recharge would amount to about 35,000,000 gallons on each square mile annually, or an average of about 100,000 gallons daily.
Quantity in Storage
The specific yield of the water-bearing materials, as computed in another section of this report, is about 20 percent. If this figure is taken as a fair average of the specific yield of the alluvium in the Neosho valley, the available quantity of water in storage at the time of this investigation amounted to about 40,000,000 gallons for each foot of thickness and for each square mile. Assuming that the average thickness of water-bearing material in the alluvium was 17 feet, the total quantity of water in storage amounted to about 680,000,000 gallons in each square mile. Part of the quantity of ground water held in storage would be available for pumping during dry seasons provided that conditions were favorable for its replenishment during succeeding seasons of normal or above normal precipitation.
Quantity of Movement
By applying the available data to the fundamental formula, Q = PIA, discussed above, the amount of water moving across a given contour line toward Neosho river may be estimated.
For this purpose, the 818-foot contour line (pl. 2) may be taken as a reference line from the point near the sharp bend in Neosho river near the southwestern corner of the artificial lake across the valley to the outcrop of the bedrock. The length of this line is approximately 1 mile. Although no test holes were drilled along this contour line, the average thickness of saturated material in the test holes shown on figure 3 is 17 feet, and it is assumed that about the same average thickness of saturated material would be found along the contour line. The average hydraulic gradient determined from the water-table contour map is about 20 feet to the mile. The average coefficient of permeability of the water-bearing material, as determined by the pumping test, is about 420, and it is assumed that this value is applicable for the portion of the Neosho valley along the contour line here considered. According to these assumptions the quantity of water that crosses the reference line under the static conditions prevailing at the time of the investigation was as follows: 420 (average coefficient of permeability) x 17 (average saturated thickness of the aquifer, in feet) x 20 (average hydraulic gradient, in feet per mile) x 1 (length of reference line in miles) = 134,400 gallons a day. Using the minimum value of 341 (table 3) for the coefficient of permeability, a similar computation indicates that the quantity of water crossing the reference line is 116,000 gallons a day.
Discharge of water from the zone of saturation may take place in several ways, including evaporation and transpiration, effluent seepage into streams or lakes, discharge of springs, and pumpage from wells.
The quantity of ground water currently pumped from wells in the Neosho river valley is negligible in comparison with the total amount available. No springs were observed and if springs are present their discharge is probably small. The many small ponds and streams tributary to Neosho river attest the effluent seepage of ground water. Neosho river is a perennial stream except in prolonged periods of drought, and receives part of its flow by seepage from the alluvium. The quantity of water discharged by effluent seepage is difficult to determine, but because the permeability of the water-bearing materials is low the quantity of water discharged in this manner probably is correspondingly small.
Although no studies of the use of ground water by plants have been made in this area, it is believed that most of the ground-water discharge occurs as transpiration. Direct evaporation of ground water also occurs, principally in the vicinity of the small ponds. If large quantities of ground water were to be pumped from wells in the valley, however, the lowered water table in the vicinity of the wells would lessen the amount of discharge by transpiration and evaporation and by seepage into Neosho river.
In June, 1943, four wells (numbers 5, 16, 28, and 33 in table 5) were selected for periodic measurement of water levels. These wells have been measured biweekly since June 2, 1943, and it is planned to continue measurements for a period of time sufficient to gain knowledge of water-table fluctuations in this area during several wet and dry seasons. The records of the measurements of the water level in these observation wells will be published in a U. S. Geological Survey Water-Supply Paper "Water levels and artesian pressure in the United States in 1943," and in subsequent Water Supply Papers of this series as long as measurements continue.
The water levels in the four wells listed above were assigned a stage of 10 feet above an arbitrary datum on October 12, 1942, a date on which all wells were measured, and subsequent measurements were referred to this datum. The highest observed stage of the four wells to date was 12.62 feet on July 1, 1943, and the lowest observed average stage was 3.70 feet on October 2, 1943. The difference between the highest and lowest stage is 8.92 feet. Most of the decline in water level occurred in July and August, 1943, during which time precipitation at Parsons, Kansas, was 5.16 inches below normal.
The magnitude of this observed decline in water level indicates (1) that considerable fluctuation in water level may be expected in this area between wet and dry periods, and (2) that the season during which this investigation was made was one when ground-water levels were at a relatively high stage.
Kansas Geological Survey, Geology
Placed on web Aug. 11, 2008; originally published March 1944.
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