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COLORADO LEGACY LAND TABLE 1. GROUNDWATER SAMPLE LOCATIONS IN ALLUVIAL EXCAVATION AREA Location ID/ Installation Easting i Northing I Ground Surface Total Well Screened Lithology Summary Elevation Depth Construction Interval Field Notes Recommendation Sample ID Date (ft) (ft) (ft amsl) (ft bgs) Details (ft bgs) (ft bgs) 2.5-inch,Sch (0-3)Fill material. Well near old concrete MW-1 11/12/1981 3,061,101.65 1,733,408.89 6,590.40 25.5 40 PVC,1/8-in 17.0-22.0 (3-23)Brown sand to silty sand,with gravel. Remove'alluvial well to ensure all contaminated alluvial slot. (23-25.5)Bedrock. containment structure. soils are excavated and disposed of in the Minnesota Adit. 2.5-inch,Sch (0-3.5)Fill material with cobbles. These alluvial wells will not yield representative data MW-2 11/21/1981 3,061,335.76 1,733,253.84 6,581.30 15.4 40 PVC,1/8-in 8.4-13.4 (3.5-21)Brown sand to silty sand,with gravel Usually dry. once the surrounding alluvium/fill material has been slot. and cobbles. disturbed/removed. The current groundwater 21-23.5 Bedrock. monitoring network(Figure 2)provides sufficient 4-inch,Sch 40 (0-15)Alluvium gravels with fine brown dirt delineation with upgradient,downgradient,and cross- MW-3A 6/19/1989 3,061,527.53 1,733,004.02 6,576.40 14.0 PVC,0.03-in 8.5-13.5 Usually dry. gradient monitoring locations. slot. (fill in parking lot). Remove MW-9. This well is no longer sampled because it is tied in with the sump system. (0-10)Fill material. Remove alluvial well to ensure all contaminated alluvial 6-inch PVC, (10-16)Mixed sand and gravel,pebbles to soils are excavated and disposed of in the Minnesota Adit. 0.5-in slot. cobbles. MW-9 11/12/2010 3,061,955.86 1,732,775.50 6,573.18 19.2 9.0-19.0 Tied in with near-by sumps. These alluvial wells will not yield representative data (16-19.2)Bedrock. once the surrounding alluvium/fill material has been disturbed/removed. The current groundwater monitoring network(Figure 2)provides sufficient delineation with upgradient,downgradient,and cross- gradient monitoring locations. 2.375-inch Sch Retain monitoring well.MW-18 is the only deep bedrock MW-18 10/11/2012 3,061,365.47 1,732,989.78 6,574.83 239.9 80 PVC,0.02- 215.0- (0-15)Fill material/colluvium. Sample Alias=L6. well in the Ralston Creek Valley near the Illinois Fault. If in slot. 235.0 (15-239.9)Bedrock needed,remove the well casing will be shortened so that MW-18 is level with the surrounding ground surface. Notes: 1 Coordinate System: NAD 1983,CORS96 State Plane Colorado Central,FIPS 0502 Feet US amsl=above mean sea level bgs= below ground surface ft=feet ID=Identifier in=inch MW=monitoring well PAGE 3 OF 10