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Executive Summary <br /> WestWater Engineering(WestWater)was requested by the U.S. Army Corps of Engineers <br /> (ACOE)to revise the October 2020 aquatic resource delineation completed for Elam <br /> Construction for their proposed 23'/4 West Pit. WestWater wetland scientists performed the <br /> original wetland delineation October 8 and 23, 2020 within the triangular-shaped survey area <br /> comprised of approximately 25±acres including 2.42 acres of Redlands Parkway ROW. The <br /> revised October 28, 2021 delineation uses Chapter 5 of the Arid West Regional Supplement to <br /> delineate the saline wetland south of the Redlands Parkway with a variable water regime affected <br /> by drought. The site hosts 8.27-acres of open water lake fringed with variable-width aquatic <br /> vegetation north of the Redlands Parkway and the saline wetland with fluctuating open water <br /> area and saline/alkali impacted soils. Site hydrology is from ground and surface water in <br /> hydraulic connection with the Colorado River located immediately south and adjacent to the site. <br /> Wetland boundaries were identified on the basis of the vegetation, soils, and hydrologic <br /> characteristics present at the site in accordance with ACOE standards included in the"Corps of <br /> Engineers Wetland Delineation Manual,January 1987" (ACOE 1987) and Regional Supplement <br /> to the ACOE Wetland Delineation Manual: Arid West Region (Version 2.0, September 2008) <br /> (ACOE 2008). <br /> On the basis of wetland vegetation, soils, and hydrology, WestWater identified 9.70 acres of <br /> potential Waters of the U.S. (WOUS) including combined acreage of open water and palustrine <br /> dugout wetlands. Palustrine wetlands include fringe surrounding open water comprised of an <br /> excavated lake and connected west channel identified as Wetland A and saline Wetland B <br /> delineated as combined open water and fringe due to the high variability in open water acreage <br /> affected by the drought and water inputs discharged from surrounding active gravel pits. <br /> Wetland A is comprised of 8.58 acres of WOUS including 8.27 acres of open water and 0.31 <br /> acre of fringe wetland. Wetland B exhibits sparse and patchy vegetation in relation to seasonal <br /> ponding with unvegetated areas impacted by saline soils in hydraulic connection with shallow <br /> groundwater. Combined open water and fringe vegetation for Wetland B is 1.12 acres. Total <br /> WOUS acreage for Wetlands A and B is 9.70 acres. <br /> Aquatic resources consist of palustrine emergent wetlands and open water areas as an artifact of <br /> past gravel mining removing gravel resource overburden and exposing the water table at or near <br /> the existing ground surface. Ponded water in the excavated lakes provides hydrology for fringe <br /> aquatic vegetation establishment. Hydric soils evolved in substrate and littoral zone soils in the <br /> excavated dugouts where soils are saturated or tension saturated in the capillary zone. Non- <br /> hydric soils occur outside the littoral zone moving up towards the more-elevated pond banks and <br /> surrounding uplands. <br /> 23'/4 Road Gravel Pit i December 2021 <br /> Aquatic Resource Delineation Report WestWater Engineering <br />