There is no detailed map available for TA-12
PRS Erosion Matrix Score Assessment Date Structure Mesa Top Bench Canyon Floor Channel Topography Explanation Ground Explanation Slope Explanation Runoff Evidence Channelized Channel Description Runoff Wetland Runoff Other Terminus Explanation Runoff Explanation Structure Run-On Structure Explanation NPDES Run-On NPDES Explanation Natural Run-On Natural Run-On Explanation ESH-18 Representative BMP Prescription BMP Description Not BMPs Sediment Comments 12-001(a) 3.6 10/14/1997 12-4 YES NO NO NO Pit 1-4, abandoned firing facility on mesa top, across Canon de Valle from TA-40. Self-contained pit. Abandoned 1953. Covered by structure. Pit is about 20 feet by 20 feet with 4 feet by 4 feet access hole, 11.5 feet deep. Inside of pit. NO NO NO Steel plate covers pit, except for opening into pit. NO NO Contamination was confined in steel pit with no possibility of affecting surface water. D. Mays NO 12-001(b) 8.8 10/14/1997 12-4 YES NO NO NO Pit east of 12-001(a), north of Redondo Road, about 3 feet deep. Sparse herbaceous vegetation in and around pit. Weeds, some bare soil. Self-contained pit - no run-off. NO NO NO None, PRS site is a depression in the ground. NO NO D. Mays NO Pit is below drainage ditch flowing east on north side of road which is protected by berm. 12-004(a) 35.0 10/14/1997 12-8 YES NO NO NO South of Redondo Road with drainage swale leading to Canon de Valle. Includes shelter and three utility posts, one of which has been cut down. Mixture of bare soil, choya, and grass/weeds. Nearly 10% leading to canyon rim. YES YES Man-made channel leading to canyon from east-most pole (cut down). Due to flat slopes and small run-off area run-off not severe. NO NO Site abandoned in 1950s. NO D. Mays NO 12-004(b) 8.8 10/14/1997 12-8 YES NO NO NO 18 inch aluminum pipe under bush on south side of Redondo Road, used to shield lanthanum radiation source. Under bush. Pipe small, so slope not too important. NO NO NO NO NO PRS protected by end of pipe sticking out above surface. D. Mays NO ER sampling has uncovered NO contamination. Suspect gamma source.