Decision Support System
When, How Often and How Long to Irrigate
|The MRGCD’s 15 automated weather stations will be a crucial factor in the Decision Support System. They’ll help determine when, how often and for how long farmers should irrigate.|
For the past 10 years the Middle Rio Grande Conservancy District has been using technology and automated gates to more efficiently get water to farmers and their crops. The improvements have helped the District cut by about half the amount of water it diverts from the Rio Grande each irrigation season.
Now, more improvements are on the way, and the District will be better able to serve farmers and their crops while maximizing the use of water.
Beginning with the 2008 irrigation season, the District will start using a computer modeling program called the Decision Support System (DSS) to help water managers and farmers determine when, how often and for how long they should irrigate.
The DSS for irrigation scheduling is the result of the cooperative work between the New Mexico Interstate Stream commission, Colorado State University and the MRGCD. The Interstate Stream Commission has sponsored the project for the past five years and has provided most of the funds for it. Sponsorship has also been provided by the Middle Rio Grande Endangered Species Act Collaborative Program. The program is being developed by a team of researchers from CSU and the ISC led by Dr. Ramchand Oad and Dr. Nabil Shafike. It will first be used in the Belen Division, which has 5,000 irrigators and 25,000 acres of irrigated cropland.
The system will be able to assist District water managers to more efficiently plan and implement their water delivery operations, thereby reducing river diversions,” Oad says. “It will take even more of the guess work out of getting water to farmers.”
The system will gather and sort through all kinds of information - things like what types of soils are in an area, how much water that soil can hold, how much water is already available in the soil, what types of crops are being grown, how quickly crops use moisture, temperature, wind speed and other weather patterns - process the information, and give District Hydrologist Dave Gensler a more accurate idea of how much water will be needed where at a given time, and for how long the water will be needed. Based on that information and the program’s recommendations of when to irrigate and how much water will be needed, Gensler will be able to more effectively schedule water deliveries.
“This will take the guess work out of irrigating and bring a little more logic to the system,” Oad says. “We’ll know how much water we have and how much farmers will need. It’s like trying to run the finances in a household. If you don’t know what is coming in and what is going out, you will soon be broke.”
|The Decision Support System will help determine how much water soils can hold, how much water plants use, and how often they should be irrigated.|
The Decision Support System will help determine how much water soils can hold, how much water plants use, and how often they should be irrigated.
“The conceptual problem addressed by a DSS for an irrigation system then is: how best to route a water supply in a main canal to its laterals so that the required river water diversion is minimized”. The pair’s paper says “The desirable solution to this problem should be “demand-driven” in the sense that it should be based on a realistic estimation of water demand. The water demand in a lateral canal service area, or for an irrigated parcel, can be predicted throughout the season through analysis of information on the irrigated area, crop type and soil characteristics. The important demand concepts are: when is water supply needed to meet crop demand (Irrigation Timing), how longis the water supply needed during an irrigation event (Irrigation Duration), and how often must irrigation events occur for given service area (Frequency of Irrigation)”.
Dr. Oad, the staff of the MRGCD and the ISC will hold informational meetings about the DSS in the coming months. “We really think this will be a tool that will help us better serve our irrigators,” Gensler says. “We’re doing all we can to help them.”