Laserfiche WebLink
Evaluation of Potential Impacts <br />From The Proposed Nix Property Sand and Gravel Operation <br />On Shallow Groundwater Levels, Water Wells and Wetlands <br />• During the growing season, groundwater ranged from 0.76 to 2.40 feet below the surface in <br />the wetland at MW-6, and ranged from 0.1 feet above to 1.60 feet below the ground surface <br />in the wetland at MW-8. <br />• Groundwater levels fluctuated over a relatively lazge range during the approximately one- <br />month of the growing season that was monitored. The maximum differences in groundwater <br />readings during the growing season are shown on Figures SA and SB. Groundwater <br />fluctuated 1.6 and 1.7 feet at MW-6 and MW-8, respectively. <br />• Groundwater continued to decline after the growing season beneath and azound the wetland <br />through April 8, 2002. Groundwater was beneath the bottoms of MW-6 and MW-8 in early <br />winter. <br />• A relatively lazge range of hydrologic conditions existed throughout the wetland. <br />The data from the piezometers indicate that moisture conditions in the wetland vary both <br />throughout the wetland and with time. These fluctuations are likely caused by changes in <br />pumping of irrigation wells, ditch diversions, and other changes in water used for agriculture in <br />the area since little precipitation occurred during the monitoring period. Groundwater levels in <br />the wetland are likely dependent upon agricultural use of water in the azea. <br />Field observations indicate that surface water sources are important for sustaining the wetland. <br />Water was observed flowing into the wetland at the three laterals indicated on Figure 2. The <br />easternmost lateral maintains surface water in the slough. The slough is relatively flat so that <br />water from the slough infiltrates and sustains groundwater beneath the wetland. Water from the <br />laterals, and in the slough, likely extends the area of saturated soil to the south and may result in <br />a larger wetland than that sustained solely by groundwater. The slough acts as a buffer by <br />controlling water levels in the wetland. Excess water is dischazged from the wetland in the <br />barrow ditch under County Road 28. <br />011-074.000 Wright Water Engineers, Inc. Page 12 <br />April 2002 <br />