Ground-water resources of Waupaca County, Wisconsin

Abstract

Waupaca County is in east-central Wisconsin. No serious ground-water problems existed in 1960 except in a few localities where crystalline rock is near land surface or is covered by nearly impermeable till. The use of ground water for irrigation has not appreciably affected ground-water levels. The county is covered by Pleistocene till, glaciolacustrine (lake), glaciofluvial (stream), and eolian (wind) deposits. In the northern three-quarters of the county these deposits overlie Precambrian crystalline rocks; in the remainder, they overlie sandstone of Cambrian age and, to a minor extent, dolomite of the Prairie du Chien Group of Ordovician age. The deposits of Pleistocene age, particularly outwash, are the principal sources of ground water except in those areas where the saturated thickness is slight or the permeability low. The sandstone of Cambrian age is an important aquifer in the southeastern part of the county. The crystalline rocks of Precambrian age yield little water except from fractures, joints, and weathered zones, and they are a source of water only in areas where better aquifers are absent. Ground water in Waupaca County occurs under both water-table and artesian conditions. The source of this ground water is precipitation that falls on the county and percolates downward to the zone of saturation. Regional movement of ground water is to the Wolf River. In most of the county the direction of movement is eastward or southeastward, except in the southeastern corner of the county, where the movement is westward. Water-level fluctuations reflect the variations of ground-water storage or artesian pressure in response to variations in recharge and discharge. Declining water levels from 1956 to 1959 reflect a period of below-normal precipitation, and rising water levels in late 1959 and 1960 reflect above-normal precipitation. Average precipitation, runoff, and evapotranspiration in 1959 are estimated to be 1,000, 400, and 600 mgd (million gallons per day) respectively. Pumpage in the county was estimated to be about 4 mgd in 1959, and about half of this amount was used for public supplies. A pumping test of a well in outwash deposits near Waupaca indicated that at that point the coefficient of transmissibility is about 100,000 gpd (gallons per day) per ft, the permeability is about 1,000 gpd per sq ft, the coefficient of storage is about 0.2, and the specific capacity is 41 gpm (gallons per minute) per ft of drawdown. These hydraulic characteristics are probably in the same order of magnitude as the characteristics of outwash deposits in the county in general. The water from wells in Waupaca County, although hard and generally containing iron, is good for most purposes.