Soil data preparation for determination of drainage lateral effect using rosetta software

Analysis of surface and subsurface drainage lateral effects is performed for a number of purposes, including compliance with the 1985 Farm Bill and analysis of wetland restoration alternatives. Lateral effects analysis conducted by NRCS is used in cases where wetland hydrology is maintained by high water tables, and potentially removed by installation of buried drains or surface ditches. The analysis assumes that water content can be determined by soil moisture characteristics computed by van Genuchten Equations, and the rate of water movement is determined by soil saturated hydraulic conductivity. With these parameters, standard lateral effect equations can be used to determine horizontal distance of lateral effect of a drainage system installation or modification. The direct measurement of necessary parameters is difficult and expensive. However, the Rosetta computer software utilizes a large number of test results for drainable porosity and saturated hydraulic conductivity that have been correlated with readily available parameters in the NRCS soils database, including texture, bulk density, moisture content, and organic matter content at 33 and 1500 kPa of plant tension. Soil data available from the NRCS Soil Data Access website is downloaded, formatted, and processed through the Rosetta program, which produces a file suitable for use in lateral effects software.