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2.0 EXISTING CONDITIONS <br />2.1. Hydro - Stratigraphy <br />The Stroh Property occurs in a broad flat valley generally trending east west. <br />This ground is referred to as the valley bottom in this report. Just south of the <br />Stroh property, the land climbs gently to the south at approximately 2% grade. <br />This ground is referred to as the valley upland in this report. <br />Stratigraphy for the Stroh property was determined by drilling observation wells in <br />summer of 2003 and test holes in summer of 2004. Offsite stratigraphy is taken <br />from test holes drilled by Thompson River Ranch contractors and published in <br />"Groundwater Investigation for Thompson River Ranch conducted by Anderson <br />Consulting Engineers in August of 2004. Test hole logs are given in Appendix A. <br />The principal aquifer in the valley bottom is composed of alluvial sand and gravel <br />(gravel) with an average thickness of 10 -15ft. Above the gravel is a layer of silt <br />and sand ranging in thickness from 4 -8ft . Below the gravel is shale bedrock. <br />South of the Stroh property and in the valley upland, a layer of sandy lean clay <br />occurs above the gravel. This layer ranges in thickness between 10 -15ft. Under <br />the gravel is shale bedrock. The sandy clay layer is a confining layer for the <br />aquifer which means the aquifer is confined where bound by the clay. As the <br />clay turns to silt and sand in the valley bottom the aquifer becomes unconfined. <br />2.1.1. Hydraulic Conductivity <br />The hydraulic conductivity of alluvial sediments in the Denver Basin range from <br />100 to 2000 ft/day. The Office of the State Engineer recommends that we use <br />600 -700 ft/day in this area. <br />The transmissivity is the product of aquifer thickness and conductivity so where <br />the gravel is 10 feet thick the transmissivity is 6000 -7000 sq.ft/day. The storage <br />coefficient for the aquifer is set to 0.000512. <br />2.2. Water Table <br />The water table varies seasonally by approximately 1 -2ft due to local irrigation <br />and precipitation both in the valley bottom and south of the valley bottom <br />contributing to enhanced recharge and higher water tables during the irrigation <br />season. The water table elevations shown in Table 2.2.1 are average elevations <br />based on measurement of onsite and offsite observation wells in June —July <br />2004. Offsite well data ( B -7 — B15) were taken from "Groundwater Investigation <br />for Thompson River Ranch" conducted by Anderson Consulting Engineers in <br />August of 2004. Onsite wells (OW -1 — OW -5) were measured by Weiland, Inc. <br />Stroh Pit <br />Groundwater Analysis Report <br />2of8 <br />