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2.1 lntroduction <br />Wetland hydrology was investigated by WestWater Engineering (WWE) at the proposed Soaring <br />Eagle Ranch gravel site located on privately owned land on the south bank and adjacent to the <br />Colorado River (Figure 1). Gravel resources sought for development by client, Grand Junction <br />Pipe and Supply Company (GJ Pipe), occur in approximately 105 acres within the 170-acre site in <br />the N''/z, Section 35; E''/z, NE'/a, Section 34; T.1 N, R.2 W; Ute PM; Mesa County, Colorado. <br />Jurisdictional wetlands were delineated by WWE in accordance with Army Corps of Engineers <br />(COE) standards in Summer 1998. Wetland delineation was submitted and approved by the COE <br />recognizing approximately 14.6 acres of wetlands within the 105-acre proposed mining site. <br />Project proponent requested the hydrogeological investigation to determine the influence <br />imgation water has on sustaining site wetlands. These site-specific data were used to revise <br />jurisdictional wetland boundaries. <br />Wells were installed at the site early November 1998 during active irrigation. Irrigation water <br />was shut-off by the end of November and remained offthrough the monitoring period ending June <br />8, 1999. Termination of monitoring corresponded with peak Colorado River discharge for Spring <br />1999 which occurced June 4-10. <br />2.2 Purpose <br />The purpose of the hydrogeological investigation was to determine if groundwater occurs in the <br />upper 12 inches of soil profile during 15% of growing season (about 27 days). Irrigation water <br />was withheld from the site to characterize temporal and spatial changes in water-table <br />configuration to determine acreage of jurisdictional wetlands not under the influence of irrigation. <br />Groundwater monitoring over the November 1998 to June 1999 period was conducted to qualify <br />overall site wetland water budget, focusing on the role irrigation plays in the system. <br />Groundwater levels were monitored over eight months to account for seasonal influences on <br />wetland hydrology. <br />2.3 Methods <br />The site was instrumented with 22 shallow piezometers placed along upland to wetland transects <br />(Figures MP-1 and W-1). Wells were drilled using a hand auger and completed with 1 inch PVC <br />pipe screened in the lower 1 foot (Table 1). Well depths range from 3 to 4 feet below ground <br />surface (bgs). Groundwater gauging events occurred monthly during monitoring period. An <br />2 <br />