The general objective of this demonstration project was to show the feasibility of alternative water management practices on the quality of drain return flow and soil salinity in the Upper Rio Grande basin. The project consists of a 450-acre demonstration site, a four-acre test site, and a hydrosalinity model. On the 450-acre demonstration site, a combination of present day irrigation techniques were used to show how, through modern water management, the irrigation return-flow quality and quantity could be improved. The feasibility of irrigating at or near 100 percent efficiency with water of medium salinity (1,200 ppm), while maintaining optimum crop yields over a period of many years were shown on a four-acre test site. The hydrosalinity model was tested for the Mesilla Valley conditions.

This report summarized progress achieved from February 17, 1976 to February 16, 1977 on the project plan of work. This interdisciplinary research effort in the second year entailed primarily reconstruction of physical equipment and monitoring farming and irrigation practices on the 450-acre demonstration farm located near La Mesa in the Mesilla Valley. A second major effort involved preiiminary testing in the Mesilla Valley of a hydrosalinity model developed by the Bureau of Reclamation for the Environmental Protection Agency. This model permits prediction of the quality of Irrigation return flow from a drainage basin. A third major area in this research effort is to study the effect of irrigating at or near 100 percent efficiency.

Project No. 3109-314