Understanding Evapotranspiration (ET)
Understanding the climate of our area, including the rates at which water evaporates to the atmosphere or transpires from plants, helps with efficient landscape watering. ET helps us save Nevada's most precious resource -water and helps improve water quality. By watering less, you avoid runoff. Overwatering causes more water to run off than soak in. This runoff could carry pollutants from the gutter into our surface water supply.
The two key ingredients to using water efficiently are knowing how much water your sprinkler system puts on your lawn and how much water your lawn needs.
Washoe County ET Project
The Washoe ET project, http://www.washoeet.dri.edu, is a network of weather stations located in the region surrounding Reno, Nevada that monitor evapotranspiration rates. These rates can then be used as a tool to estimate lawn and crop watering needs. The following links provide specific rate data:
Gross Estimated Runtimes for Small to Medium Turf AreasMonthly Evapotranspiration Rates for various areas in Washoe County
The All Seeing, All Knowing Lawn Care Manual is also available at this site.
This project is sponsored by the Washoe County Regional Water Planning Commission in conjunction with Washoe County Department of Water Resources, the University of Nevada Cooperative Extension, Desert Research Institute's Western Regional Climate Center, UNR College of Agriculture, Biotechnology and Natural Resources, and the Nevada Landscape Association.
TMWA's ET Controller Pilot Program Saves Water
TMWA successfully partnered with local landscapers between 2003-2006 to research the effectiveness of using ET controller technology to control watering of irrigated areas. Using historical ET rates and the day's temperature, the new controllers adjust the amount of water applied to the landscape.
Several irrigated areas around commercial properties and large homeowner association landscaped areas in Reno and Sparks were selected to test the ET controllers on a total of 16 acres of landscaped area. The sites participating in this 3-year pilot program were monitored and have shown a 20 percent drop in water use compared to their historical usage, a savings of about 6.3 million gallons of water annually!
To become ET savy and learn more about watering according to local ET rates, log on to www.washoeet.dri.edu.
