Devils Lake Basin Water Utilization Test Project
Dean Steele and David Hopkins
Above-average rainfall in the last twelve years has led to rising water levels in the Devils Lake basin in northeastern North Dakota. An irrigation test project was started at ten farmer-cooperator field sites withing the basin to estimate how much additional water can be utilized via irrigation of agricultural crops. The objectives of the project are to: 1.) Determine how much additional surface water in the Devils Lake basin can be utilized via sprinkler irrigation of agricultural crops compared with non-irrigated corps, 2.) Evaluate the effects of irrigation on representative soil map units within the basin, and 3.) Extrapolate results from the test project to estimate the total volume of water that could be prevented from entering Devils Lake through extensive development of irrigation in the basin. (From Gautam, R., D. Steele, D. Hopkins, and M. Sharp. 2006. Assessment of SEBAL model for estimating evapotranspiration in the Devils Lake basin. ASABE Paper No. 062207. St. Joseph, Mich.: ASABE).
Water balance monitoring at the sites include measurements of rainfall and irrigation, soil water content, deep percolation, and ground water levels. Irrigation scheduling recommendations are being made according to an NDSU Extension bulletin. Soil samples are being taken for physical, chemical, morphological analyses. Water samples are being analyzed to help determine salt balances and movement. A remote sensing based energy balance algorithm will be applied to estimate evapotranspiration (ET) in the basin. Correlations will be developed between ET and soil physical and chemical properties affecting sustainability as well as other factors, such as crop types, soil map units, and landscape position in order to assess the feasibility, impact and sustainability of larger-scale irrigation in this mostly non-irrigated basin. (From Gautam et al., 2006.)
Major Results and Conclusions
The study is in progress. The 2005 growing season and early months of 2006 were used to install instrumentation and obtain baseline soil salinity surveys. The first full season of irrigation was 2006, during which rainfall and irrigation averages across all sites were 185 mm and 199 mm, respectively. In 2007, rainfall and irrigation averages were 357 mm and 71 mm, respectively. We have asked for a one-year extension of the project to obtain data from the 2008 growing season, which will provide more time for the effects of irrigation to exhibit themselves on the soils of the basin. A longer-term study is desired because many of the soils in the basin are classified as conditionally irrigable.