|Davis, Austin - University Of Missouri|
|Thompson, Allen - University Of Missouri|
|Bjorneberg, David - Dave|
|Lohani, Sapana - University Of Nevada|
Submitted to: Soil and Water Conservation Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2018
Publication Date: 7/29/2018
Citation: Davis, A., Thompson, A., Baffaut, C., Bjorneberg, D.L., Lohani, S. 2018. Evaluation of Soil Vulnerability Index (SVI) for an intensively managed high desert irrigation district. Soil and Water Conservation Society Conference, July 29-August 1, Albuquerque, New Mexico. p. 49, SWCS Abstract Book.
Technical Abstract: The Soil Vulnerability Index (SVI) is an index created for the purpose of rapidly assigning risk categories for runoff and leaching at the field and watershed scale. The SVI was developed for cultivated agricultural lands in humid environments, and is now being evaluated for suitability in other more arid ecosystems. The risk categories are “low”, “moderate”, “moderately-high”, and “high”. The SVI was determined based on USGS digital elevation maps (DEM) and RUSLE2 related soil attributes obtained from SSURGO. Classification relies on various statistical cut-off thresholds for slope and the soil erodibility K-factor, dependent on the hydrologic soil group. The objective of this project is to apply the SVI to the Twin Falls Canal Company Irrigation District in the Upper Snake Rock watershed, which is the first evaluation in the western United States. This is a high desert, sage-brush ecosystem that was converted to farmland around the turn of the 19th century, with surface irrigation withdrawn from the Upper Snake River. All crop production in the area requires irrigation due to the very low annual precipitation, therefore canals provide water from the upstream reservoir. Drainage is also present in the district. Topography in this watershed is mostly flat, and soils are predominantly in hydrologic groups C and D. Despite its efficacy in eastern agricultural watersheds, it remains to be seen if SVI will allow for appropriate differentiation between fields when applied in more homogenous Western landscapes. Initial results for the region indicate useful distinction for the runoff classification, while for leaching this is less obvious, as there is little spatial variability in the leaching factors.