Location: Water Management ResearchTitle: Integrated on-farm drainage management for drainage water disposal Author
|Ayars, James - Jim|
Submitted to: Journal of Irrigation and Drainage
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2013
Publication Date: 2/1/2014
Citation: Ayars, J.E., Soppe, R.O. 2014. Integrated on-farm drainage management for drainage water disposal. Journal of Irrigation and Drainage. 63(1):102-111. Interpretive Summary: Sustainable irrigated agriculture will require that ways be developed to minimize the impact of the discharge of saline subsurface drainage water into surface streams. Drainage will always have to be a component of irrigated agriculture. However, there are methods that can be implemented to control and minimize the volume of drainage water being discharged. Improved irrigation management is the first step to reduce the volume of water. The next step is to implement a reuse system to capture deep percolation losses using a drainage system and then use the captured water as supplemental irrigation. The successive reuse will reduce the volume of deep percolate and increase the salinity to a level that is no longer suitable for crop use. This system has been dubbed Integrated On-Farm Drainage Management and was demonstrated on four 64 hectar fields on the Westside of the San Joaquin Valley. It resulted in a significant reduction of the total drainage flow and the land area needed for final water disposal. This system will provide a solution to the problem of drainage water disposal while alternatives for permanent disposal are developed.
Technical Abstract: Providing environmentally safe methods for drainage water disposal is a significant challenge for irrigated agriculture. Subsurface drainage water contains salt and nutrients that may have significant deleterious effects on surface water quality. A system was developed for the reuse of saline drainage water for supplemental irrigation that resulted in a significant reduction in the total drainage volume. This system is called Integrated On-Farm Drainage Management (IFDM). It was demonstrated on four 64 hectare fields located on a farm on the Westside of the San Joaquin Valley of California. Three of the fields were used to grow salt sensitive crops (tomato, garlic) and the fourth was used to grow progressively more salt tolerant crops. Subsurface drainage systems were installed on all fields at a maximum depth of 1.8 m and had controls to regulate shallow water table position and drainage flow. The total drainage flow from the site represented 0.7% of the applied water. The area used for salt tolerant crops was less than 6% of the total area served compared to previous designs using evaporation ponds that required areas equal to greater than 10% of the served area. The results demonstrated that the regional groundwater quality masked the concentrating effect of crop water use by decreasing the average salinity of the drainage water. Deep percolation from the fields contributing to the reuse area ranged from 6 to 10% of the total applied water.