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Mr. Bill Buglass ZGEO, LLC Hydrogeologic Assessment tir loess; 2) upper Paleozoic (Ordovician and Cambrian age) sandstones and dolomites; 3) shale and siltstone of the Eau Claire Formation of Cambrian age; and 4) sandstones of the Eau Claire and Mt. Simon Formations of Cambrian age. The uppermost sand and gravel aquifer and underlying bedrock aquifer are separated from the productive lower sandstone aquifer by a thin layer of dolomitic shale and siltstone which acts to retard vertical groundwater flow (Figure 1). The 1993 well construction report for the well at the Site indicates that the water table is at a depth of 31 feet below ground surface (bgs) at an approximate elevation of 951 feet msl. Bedrock was noted to be at a depth of approximately 190 feet bgs. The well construction report and geologic log for the village of Brooklyn municipal well (No. 2) indicate that the bedrock underlying the area consists of dolomite and sandstone of the Jordan Formation, late Cambrian in age. This well is cased 283 feet bgs into the underlying Tunnel City Formation and is open to the Wonewoc, Eau Claire and Mt. Simon Formations to a depth of 670 feet bgs. Based on the well construction reports reviewed for the area, approximately 74 percent of the private wells constructed since 1970 are completed in the sandstone formation underlying the sand and gravel. In general, the water table reflects the topography. The ground surface and the underlying water table rise to the west of the site (Figure 2). Thus the general direction of groundwater flow in the unconsolidated aquifer is from west to east with the groundwater divide located just over two miles to the west of the Site (Bradbury et al., 1999). Based on a comparison of the water table elevation to the potentiometric surface elevation of the deep Mt Simon aquifer, groundwater in the general area of the Site moves downward to recharge the groundwater flow system. According to Mr. Bob Anderson, Director of Public Works, village of Brooklyn, a wellhead protection plan has yet to be completed for the village. He estimated that the plan should be prepared in approximately eighteen months. A municipal well `zone of contribution' analysis presented in the Dane County Groundwater Protection Plan (see maps 21 and 22, DCRPC, (Ilov 1999) indicates that for projected 2020 pumping rates the proposed mining Site is not located within the supply area of the Brooklyn water supply wells (Figure 3). ASSESSMENT OF POTENTIAL HYDROGEOLOGIC IMPACT Groundwater quantity impacts are dependent upon changes in the groundwater budget (inflows and outflows). As the operational plans do not call for groundwater pumping to supply wash water, impacts associated with pumping would not occur. Private wells in the area would not be impacted. Minor changes in the water budget would occur as a result of the proposed operation with the removal of sand and gravel overburden, creation of a 11.2 acre pond, and construction of earthen berms to control stormwater runoff. Changes in the inflows and outflows would likely result in small increases or decreases in groundwater elevations. These minor changes in groundwater elevations, if any, are expected to be insignificant. Additionally, it is not expected that the direction of groundwater flow at the Site would be significantly altered. The groundwater quality in Dane County is generally good (DCRPC, 1999). A review of the WDNR database for the area near the proposed Site revealed that nitrate—nitrogen concentrations in groundwater were elevated in some wells but concentrations did not exceed the health advisory level. Some wells also had detections of atrazine-like compounds. Aquifer susceptibility to contamination was evaluated by The Dane County Regional Planning Commission based on Fritz's thesis (1996) which considered three factors: soil attenuation potential; hydrogeologic setting; and distribution of groundwater recharge and non-recharge areas. The resultant contamination risk maps indicated that groundwater is susceptible to contamination from any surface or subsurface activity in many areas of Dane County including the proposed Site. To minimize the potential risk of the proposed operation to adversely impact co. v groundwater quality, chemicals would not be used or stored at the Site, fuel would not be stored c:\.my docs\zgeo 2003\P&D 10/30/03 3