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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
48-001 34.0 9/24/1997 48-1 YES NO NO NO   a)  Areas of side of road - sparse vegetative cover.

c)  Roadway and asphalt covered areas along side of Building 48-1.		 a)  roadway

c)  off to north and east of building 48-1 along side of canyon.		 NO NO Air stack emissions from area stacks run-off not completely determinable throughout entire site survey.         YES   NO   YES Contoured slopes and drainage pathways heading away from site. R. Reynolds     NO  
48-002(a) 15.3 7/30/1997 48-1 YES NO NO NO       NO NO           NO   NO   NO   C. McLean   Areas covered with tarp during excavation, clean backfill provided and revegetation measures applied. BMPs installed 8/31/95 (V. Hesch, 4/98).  BMPs inspected: 8/31/95 (V. Hesch, 4/98) NO  
48-002(b) 15.3 7/30/1997 48-1 YES NO NO NO       NO NO           NO   NO   NO   C. McLean   Areas covered with tarp during excavation, clean backfill provided and revegetation measures applied. BMPs installed 8/31/95 (V. Hesch, 4/98).  BMPs inspected: 8/31/95 (V. Hesch, 4/98) NO  
48-002(e) 22.3 7/30/1997   YES NO NO NO Inside fence at TA-48.     NO NO           YES From slanted roof of building. NO   NO   C. McLean     NO  
48-003 40.7 9/2/1999   YES YES NO NO PRS extends from site of old septic tank E of TA-48 to bench within Mortandad Canyon. Vegetation is mixed grasses with exposed volcanic tuff.  Dense canopy cover below mesa's edge. Flat on mesa top, greater over canyon edge. YES NO Runoff is mostly sheet flow from area where septic was located to the mesa edge. Bench   Sheet flow runoff terminates within bench setting below site. Sheetflow run-off below site of old septic tank. NO None observed. NO None. YES Sheet flow from surrounding terrain. Veenis, Steve Visible debris, mostly windblown trash.   NO Site was re-evaluated base on a recommendation from the SWAT.  (Originally assessed on 07/30/1997, score 60.5).  NMED was originally copied 8/20/97.
48-007(a) 55.8 7/30/1997   YES NO YES NO NPDES outfalls to existing wetland.   10 - 30% on mesa top. YES YES Culvert from outfalls.         YES Run-off from parking lots. YES NPDES outfall. NO   T. Lemke     NO Combined with PRS 48-010 at SWAT meeting 12/9/97.
48-007(b) 49.3 7/30/1997   YES YES NO NO PRS extends from NPDES outfall to bench within Mortandad Canyon. Active outfall, heavy vegetation.   YES YES           YES NPDES outfall. NO   YES Sheet flow down slope from surrounding area. T. Lemke     NO Heavy vegetation acts as natural BMP.
48-007(c) 69.5 7/30/1997 48-1 YES YES NO NO PRS extends from NPDES outfall on mesa top to bench within Mortandad Canyon.   Outfall at edge of canyon. YES YES NPDES outfall.       Evidence of erosion just below outfall. No visible evidence beyond canyon edge. NO   YES PRS is NPDES outfall. YES Sheet flow down slope around PRS T. Lemke     NO Vegetation, logs and rocks just below outfall act as natural BMP. Erosion possible down steep slope beyond canyon edge.
48-007(d) 55.8 7/30/1997   YES NO YES NO NPDES outfalls to existing wetland.   10 - 30% on mesa top. YES YES Culvert from outfalls.     Wetland east of TA-48.   YES Runoff from parking lots. YES NPDES outfall. NO   T. Lemke     NO Combined with PRS 48-010 at SWAT meeting 12/9/97.
48-007(e) 3.6 9/24/1997 48-8 YES NO NO NO Grassy, meadow-like area between building and Mortandad Canyon Thick grasses, down natural wood, weeds. Gentle slope NO NO           NO   NO Former NPDES outfall EPA 04A126 no longer outfalls to environment - redirected to internal process. NO   D. Mays     NO Trash:  A few aluminum cans, pieces of cardboard, etc. (no big problem).
48-007(f) 76.5 7/30/1997 48-1 YES YES NO NO PRS boundary extends from outfall on mesa top to bench within Mortandad Canyon.     YES YES Gully formed from run-off.       Evidence of sediment transport within gully, and along channel banks. YES Outfall is from run-off, from asphalt surrounding TA-48-46. NO   YES Sheet flow from surrounding terrain. T. Lemke     NO Energy dissipaters within gully below outfall.
48-009 22.3 9/24/1997   YES NO NO NO Asphalt covered road. Loading dock spill from compressors located under overhead cover, asphalt covered road. Level roadway. NO NO           YES   NO   NO   R. Reynolds     NO  
48-010 80.3 7/30/1997   YES NO YES NO PRS extends from wetlands on mesa top to bottom of Mortandad Canyon.   10 -0 30% on mesa top, >30% over canyon edge. YES YES Leaving wetlands area.       Gully formed at edge of canyon. NO Cooling water from NPDES outfalls contribute to run-on. NO   YES Drainage from wetland area. T. Lemke Straw bales or other energy dissipater at canyon edge.   NO Evidence of erosion and run-off discharge at canyon edge.  This PRS was considered along with its contributing PRSs, 48-007(a) and 48-007(d) at the SWAT meeting of 12/9/97.