Calculation of Soil Erosion Of a Mine area in NM with the help of GEOWEPP software.

 

Background:

Erosion is a natural process. It is the surficial counterpart of the weathering of parent material. If erosion did not occur, soils would get thicker and thicker. Erosion is the natural wearing away. Literally, erosion is the movement or transportation of material which was soil but becomes sediment as soon as it begins to move. Soil erosion is generally caused by the washing away of soil by water,wind and ice. It is important to measure erosion to measure the Loss of quality  topsoil for  agriculture, Change of surface, Change of topography, To measure instability of soil for construction of structures, Slope instability etc.

 

       Methods:

 

             DATA SOURCES:

 

 

·         Raster ASCII

·         UTM Zone 13N

·         Soil: Sandy loam

·         Soil Management: 18% covered short grass covered.

·         Critical source area(CSA):5hectares

·         Minimum source channel length(MSCL):100 meters

·         Resolution:30m DEM

·         Climate Station: DULCE NM – 292608  , NM

·         T-Value: 0.01 tons/acre/yr

·         Years: Years:100(for WEPP); 2 (for GEOWEPP)

·         Software: ARCGIS 9.3, TOPAZ,WEPP.

·         LAPLATA MINE AREA.(location)

 

 

 

PROCESS:

The amount of soil erosion of the watersheds was calculated using GEOWEPP. 

 

·         My data was TIN data so I have converted tin to raster by 3D analysis toolbar.

·         Than by the help of Conversion tool I have converted raster to ascii file.

·         My DEM resolution is very large so I have change it to 30m DEM resolution.

·         Import the ASCII file to GEOWEPP software.

·         TOPAZ software create the channel network.(image of channel network)

·         Select the outlet point.(image)

·         GEOWEPP software create the expected watershed. (image)

·         Select the climate station (DULCE NM – 292608  station new mexico.)

·         Select the soil management and soil data.

·         After the first run change T value to .01 tons/acre/yr.

·         Rerun WEPP software

 

 

Result: Click on Images for details

 

ABSOLUTE SOILLOSS VALUE

 

            ABSOULUTE SOIL LOSS.gif

 

 

 

 

 

ABSOLUTE SEDIMENT YIELD VALUE

 

            ABSOULUTE SEDIMENT Y.gif

 

 

         

    FINAL OUTPUT (flow path method)

 

     FLOW PATH.gif

 

   

    FINAL OUTPUT(watershed method)

 

      WATERSHED.gif

 

 

      WEPP software output:

 

          WEPP.gif

 

 

 

Conclusion:

 

So, We get the soil erosion and deposition of a selected area by this project. From the result we can found the soil loss and deposition is very little. Because the simulation year for GEOWEPP is only two years.And also I have considered the area is 18% grassland and the rest of the land is uncovered  and the soil is sandyloam. But all of the soil of this area was salvaged and placed into stockpiles until mining was completed.  So it was handled twice when salvaged and returned to the regraded areas, and pretty thoroughly mixed together. So, I think it is a very loose soil. So soil management should be changed.

 

 

 

Future Work:

— Comparison of  real data with software  outputs is very important. So we have the idea about the error level of the software calculation.

— Use of own climate data than prism data is also important because prism data is based on precipitation, temperature only. I like to add the wind data as wind has a great influence on erosion.

— Working with  all the inputs that the geowepp software needs as SOILSMAP.txt, SOILSDB.txt, LANDUSE ASCII, LANDCOVER.txt, LANDUSEbd.txt, TOPO image, USGS Land use Classification will give a more perfect result.

 

Acknowledgements:

o   Dr. Julie E.A. Coonrod,

Dr. John C. Stormont,

Civil Engineering Dept,

University of New Mexico.

o   Dr. Chris Renschler

The State University of New York at Buffalo.

o   Dave Clark

NM Mining and Minerals Division