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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 36-001 45.7 12/9/1998 NO NO YES NO Located near Lower Slobovia within large floodplain area of a tributary to Potrillo Canyon. Known as MDA AA. Vegetated cover of grasses and weeds with some exposed soils. Gently sloping to the east within the floodplain. YES NO Rill erosion observed eastern portion of site. meadow/floodplain Bar ditch along access road collects runoff and conveys under road through culvert to the east. The flow appears to terminate with the large meadow/floodplain which is heavily vegetated. Rill erosion observed across the eastern portion of site. Several rills have BMPs in place (riprap) to impede further erosion. NO None NO YES Natural upslope drainage from tributary of Potrillo Canyon. Steve Veenis Some rills do not have riprap installed and are visibly transporting sediment from the site. Rills filled with riprap and anchored with galvanized wire (gabion like) - effectively stopping erosion (1996) NO 36-003(b) 50.2 7/19/1999 YES YES NO NO Septic tank/outfall near I-J Site. Outfall over mesa edge (could not locate) onto bench setting. Moderate vegetative cover with barren areas on slope. Tank location flat, outfall onto moderate slope YES NO Some evidence of sheetflow runoff from site. Sheetflow runoff from site flows over mesa edge into adjacent canyon Sheet flow erosion near outfall area (potentially rill erosion) observed nearby where outfall is believed to exist. NO None NO None YES Upslope drainage. Veenis, Steve NO I-J Site in general needs run-on, sediment/erosion controls implemented. 36-004(a) 48.5 12/9/1997 36-36 YES NO NO NO On mesa top but situated in small drainage area located beside Potrillo Canyon a) Very limited vegetation on pad.
Fairly level pad. YES NO PRS does not have definitive boundaries. Site of detonation pad located approximately 50 yards from edge of Potrillo Canyon. Sheet flow off of pad into man-made drainage contoured to flow. NO NO YES Major storm water activity at the site. Run-on from south side of site area. R. Reynolds BMP should be placed at northwest corner of site to mitigate discharge potential to Potrillo Canyon. NO Although 6-8" of snow hampers visibility of surface.
Run-on diversion controls needed.
36-004(b) 57.3 12/9/1997 36-36 YES NO NO NO Meenie site located within small drainage area at the head of a tributary to Fence Canyon. Majority of site does not have much vegetation on it at all. Fairly level pad. YES YES Natural channelized rivulets convey run-off off site to the east. Sheet flow of detonation pad to main channel. Rill evidence around edges of pad and main channel. NO NO YES Surrounding canyon walls as well as well defined drainage channel passing through and around site. R. Reynolds Water bars, check dams or non-combustible materials. NO Debris (wire, plywood, scrap metal) laying in drainage area.
No BMPs in place
36-004(c) 68.3 12/9/1997 36-36 YES NO NO NO Minie site - pad located within drainage area. Head of Potrillo Canyon. Pad & surrounding area void of any vegetation. Fairly level pad. YES YES Upper pad has channel draining around it to the south. Channel widens out and provides run-on for lower detonation pad, narrowing at lower end of pit. Run-off drains around lower detonation pit - continues on further down into canyon. Gully drains around pit, small rill throughout site. Upper pad does not appear to have significant amount of run-off evidence. YES Upper activity (bunker, building) & parking lot creating run-on to lower pit site. NO N/A. YES Natural drainage pattern is right through lower end of PRS. R. Reynolds BMPs around pad - snow cover prevents determination of extent of erosion. NO Presence of debris, undeterminable due to 6-8" of snow on ground.
Run-on and run-off controls recommended.
36-004(d) 33.0 8/25/1997 36-12 YES NO YES NO "Skunk Works" upstream from Lower Slobbovia. "Burn Pit South" approx. 100 feet south and 250 feet east of Potrillo Road/Moe site interaction. Heavy pinon and juniper cover at "Burn Pit South". Slight slope down to channel. NO NO NO NO YES Some run-on at "Burn Pit South" but all water is retained. D. Mays Remove down wood structure and dispose of in Lower Slobbovia burn pit. Earth berm to divert run-on. NO This site is an 8x4 foot pit covered with three doors, 24"-27" deep. It acts as its own sediment/detention pond. "Burn Pit South approx. 8 feet deep and 30 feet across - again, it is its own sediment/detention pond. 36-004(e) 57.3 11/4/1997 YES NO NO NO I-J firing site on mesa top north of Potrillo canyon. This PRS is now located within TA-36 and is adjacent to C-36-006(e) and 15-008(f). Area is primarily bare sand. No canopy cover and very little ground cover. Generally flat but slope increases to the south at the edge of mesa YES NO Runoff is visible in erosional features near mesas edge. Runoff terminates directly into Potrillo Canyon on the south edge of site. Rill erosion present at several locations on the site. YES Run-on from the adjacent asphalt roadway to the northeast. NO YES Sheet flow from surrounding area. T. Lemke Energy dissipaters at north end of site (points of run-on) and silt fences or straw bales at south end to control sediment transport. NO Almost no vegetation on site. Soil is loose sand. Evidence of erosion exists. Assessment data from field visit 11/4/97.
Trash on site includes depleted uranium, metal, plastic, Plexiglas, and wood scraps.
36-005 45.4 8/25/1997 36-7 YES NO NO NO Boneyard. East of Meenie and Minie sites. Some canopy and vegetative cover but mostly soils. YES YES Several small rills fan out across Boneyard site. Meadow east of Minie site. Natural rills fan out and dissipate in meadow. NO NO YES Natural sheet flow run-on D. Mays NO The whole site is "visible trash or debris". Not in any watercourse per se. 36-006 78.0 8/25/1997 NO NO NO YES North of TA-36 Eenie site, on south bank of Potrillo Canyon creek. Almost no vegetation; some deciduous cover. Estimate >50%. YES NO Rill at east end of dump, half way down. NO Asphalt diversion dike at top appears to be working. NO NO The PRS is protected by the run-on BMP. D. Mays Clean out existing BMP, asphalt diversion dike.
Stabilize slope with jutemat and reseeding to prevent further deterioration.
Asphalt diversion berm. Regrading and re-contouring of firebreak road above site into a retention area. NO Visible cables, wire, concrete and misc. debris observed over canyon edge adjacent to and in defined drainage entering canyon. 36-008 52.0 12/9/1997 36-1 YES YES NO NO Near NPDES outfall on the north side of TA-36-1. Surface disposal area on slope behind building. Canopy cover consists primarily of pines. Hillside has little vegetation. Hillside covered with pine needles. Slope steepens at mesa's edge and gradually levels out on canyon floor. YES NO NPDES outfall previously discharged directly onto canyon side slope on eastern boundary. Large drainage swale on western boundary. Sheet flow run-on/runoff from surrounding area. Sheetflow and drainage swale discharges likely terminated in canyon below. Sheet flow erosion inferred from the steepness of slope at end of pipe. YES Roof drains and run-off from parking area above run-on to the site. YES Former NPDES outfall EPA 06A106 located nearby. YES Sheet flow down surrounding slope. Veenis, Steve Straw wattles have been placed below the site to slow sediment migration. Run-on controls were placed on mesatop near asphalt edge. NO The Cerro Grande Fire exposed debris scattered around the slope. This is a new PRS located adjacent to C-36-003. C-36-001 57.3 7/22/1999 36-55 YES NO NO NO Located near I-J firing site on mesa top north of Potrillo canyon. Area is primarily bare sand. No canopy cover and very little ground cover. Generally flat but slope increases to the south at the edge of mesa YES NO Runoff is visible in erosional features near mesas edge. Runoff terminates directly into Potrillo Canyon on the south edge of site. Rill erosion present at several locations on the site. YES Run-on from the adjacent asphalt roadway to the northeast. NO YES Sheet flow from surrounding area. Veenis, Steve Energy dissipaters at north end of site (points of run-on) and silt fences or straw bales at south end to control sediment transport. NO Almost no vegetation on site. Soil is loose sand. Evidence of erosion exists. Assessment data from field visit 11/4/97.
Trash on site includes depleted uranium, metal, plastic, Plexiglas, and wood scraps.
C-36-003 52.0 12/9/1997 36-1 YES YES NO NO NPDES outfall on the north side of TA-36-1. Outfall discharges at the edge of Three Mile Canyon. Canopy cover consists primarily of pines. Hillside has little vegetation. Hillside covered with pine needles. Slope steepens at mesa's edge and gradually levels out on canyon floor. YES NO Outfall previously discharged directly onto canyon side slope. No channelization was observed. Sheet flow run-on/runoff from surrounding area. Outfall discharges likely terminated in canyon below. Sheet flow erosion inferred from the steepness of slope at end of pipe. YES Roof drains and run-off from asphalt run-on to the site. YES PRS is NPDES outfall EPA 06A106. YES Sheet flow down surrounding slope. Veenis, Steve Run-on controls at top and sediment retention at toe of slope. NO Outfall discharges onto a steep slope with limited vegetation. Debris scattered around the slope, but not related to the PRS being assessed. C-36-006(e) 15.3 12/9/1997 YES NO NO NO On mesa top at edge. Minimal vegetation. Level activity area. NO NO NO NO NO Drainage does not leave the site. R. Reynolds NO Site was evaluated while under the cover of snow. Therefore, the presence of debris was unable to be determined.