Project Number: 5368-13000-007-01
Project Type: Reimbursable

Start Date: Oct 01, 2004
End Date: Dec 31, 2008

Objective:
1. Identify the effect of converting surface irrigation to overhead irrigation on selected water quality parameters at the irrigated field, drainage, and watershed/tract scale. 2. Calibrate and validate watershed assessment model(s) for irrigated tracts. 3. Determine the most effective placement of the overhead irrigation systems.

Approach:
We propose to measure the water flow, suspended sediment, and total and dissolved phosphorus in selected individual irrigation return flow surface drains during the irrigation season. The individual surface drains are spatially and hydrologically isolated and can serve as sub-basins or smaller watersheds (similar to HUC 10 or 12). This data will be related to the crops and cropping practices, animal waste applications, and distribution of irrigation systems within each of the drainage areas. Some information will be estimated from current aerial imagery and agency databases, as well as from field surveys. This information will be used to determine the relative effect of irrigation system on return flow water quality parameters, and to validate watershed assessment models for irrigated tracts. The models may then be used to identify the most beneficial placement of overhead irrigation systems in the tract, as well as the effect of other conservation practices on water quality and quantity. Documents reimbursable with NRCS. Log 27436. Formerly 5368-12130-009-02R (6/07).