- irrigated acreage evaluations
- consumptive use analyses
- digital analyses of aerial photographs
- crop surveys
Determining historical and present-day irrigation practices to evaluate water rights, establishing beneficial use, or simply quantifying irrigation water use can be challenging. INTERA meets these challenges through the use of sophisticated forensic mapping techniques that integrate digital historical aerial photography, mapping, and documentation. Our GIS-based analyses, coupled with a practical understanding of on-farm irrigation practices gives us a unique toolset to evaluate historical irrigation patterns and determine water-right reliability. For analyses of irrigated lands over large areas (50,000 – 100,000 acres or more), INTERA applies methods based on satellite imagery such as Landsat. We have developed automated techniques that enable us to evaluate the location and timing of irrigation across the entire Landsat period of record (dating back over 40 years). In addition to determining the spatial and temporal distribution of irrigated lands, we estimate actual consumptive use by applying remote-sensing based energy-balance methods to quantify crop consumptive use. When quantified over large areas, such as an entire irrigation district, water managers are able to examine water balance on a basin scale, resulting in more informed water-management decisions.