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Evaluation of Potential Impacts <br />From The Proposed Nix Property Sand and Gravel Operation <br />On Shallow Groundwater Levels, Water Wells and Wetlands <br />for the county road, and where a ditch {"slough") was dug years ago, presumably to improve <br />agricultural drainage conditions (Photographs 2 and 4). The wettest portion of the wetland is <br />dominated by three-squaze bulrush, with some azeas of hazd-stem bulrush and cattails. These <br />species typically occur in areas with seasonally or perennially saturated soils and often standing <br />water. Slightly drier azeas of the wetland that have saturated soils, but not substantial standing <br />water, are dominated by spike rush, Nebraska sedge, hairy sedge and three-square bulrush. The <br />driest portion of the wetland, which occurs along its southern and western edges, is dominated by <br />drier species including foxtail barley, and salt grass. Canada thistle, sweet clover, and pasture <br />grasses also occur in drier portions of the wetland and areas adjacent to the wetland (Photograph <br />1). <br />The wetland lacks trees and shrubs. However, the owner of the Sage Hill Farm has planted <br />willows in the northern portion of the wetland south of County Road 28 (Photograph 2). <br />The soil survey shows Vona sandy loam as occurring in the wetland. This is not a hydric <br />(wetland) soil mapping unit. Soil pits dug in the wetland found a 0- to 2-inch surface horizon of <br />silty loam-to-loam soil. This horizon was underlain by a thicker layer of silty, gravely, or sandy <br />clay. This subsoil horizon was saturated at the time that the soil pits were dug (August 14, 2001) <br />and exhibited a dark color and redoxymorphic features indicative ofwetland soils. <br />During field observations, water was observed flowing into the wetland from three irrigation <br />laterals on the south side of the wetland (Photographs 3, 5 and 6). The approximate locations of <br />these laterals are shown on Figure 2. One of the laterals discharges into the slough on the east <br />side of the wetland (Photograph 6}. A water control box near the north end of the slough governs <br />the water elevation in this portion of the slough. This box has adjustable "stop logs" that can be <br />used to change the water level in the slough. Water from the slough discharges into a barrow <br />ditch south of County Road 28. Water in the barrow ditch flows westward to a point where it is <br />conveyed north under County Road 28 by a culvert. <br />ott-o~a.ooo <br />April 2002 <br />Wright Water Engineers, Inc. <br />Page 3 <br /> <br />