What is the TXHPET Network?

The Texas High Plains ET Networks (North Plains and South Plains networks) were established in the 1990’s to provide convenient and timely access to agriculturally based meteorological data for use by producers, agricultural researchers, and others interested in agriculturally relevant meteorological data. 

The Texas High Plains Evapotranspiration Network is the result of intensive collaboration and cooperation between the North Plains Evapotranspiration Network and the South Plains Evapotranspiration (ET) Network. The Texas North Plains and South Plains ET Networks are comprised of meteorological stations located throughout the Texas North Plains and South Plains region. The two networks have been effectively combined to form the Texas High Plains ET Network. Under the combined operations, the TXHPET operates 18 meteorological stations located in 15 Texas counties, and regional coverage is estimated at four million irrigated acres. Additional meteorological stations, representing a substantial increase in area coverage, may be added to the TXHPET network in the future. The network disseminates meteorological data, including ET-based crop water use information used by agricultural producers and consultants in irrigation scheduling, on a daily basis. Currently, these data are disseminated primarily through fax and / or on-line web access to over 825 data users per day (approx. 300,000 downloads and faxes annually).     

                                                                                                        Bushland (ARS)
                                                                                                        Bushland (JBF)
                                                                                                        Chillicothe
                                                                                                        Dalhart
                                                                                                        Dimmitt
                                                                                                        Earth
                                                                                                        Etter
                                                                                                        Farwell
                                                                                                        Halfway
                                                                                                        Lamesa
                                                                                                        Lockney
                                                                                                        Lubbock
                                                                                                        Morse
                                                                                                        Munday
                                                                                                        Pecos
                                                                                                        Perryton
                                                                                                        W.T. Feedlot
                                                                                                        Wellington
                                                                                                        White Deer                              

What is evapotranspiration (ET)?

Evapotranspiration is a term that describes crop or plant water demand by combining evaporation and transpiration. Evaporation is the process through which water is removed from moist soil and wet surfaces (such as dew on leaves). Transpiration is the process through which water is drawn up through the plant (roots extract water from the soil, and water is eventually removed through stomata on the leaves.)  ET is an estimate of crop water demand and is driven primarily by meteorological conditions, including air temperatures, humidity, solar irradiance and wind. These data are acquired through use of specially equipped meteorological "weather" stations. Strategically located meteorological stations comprise the ET networks. Data from these stations are applied to an ET model (equation) to calculate reference crop (well watered grass or alfalfa) ET.

What is Reference ET (PET)?

Reference crop evapotranspiration, also referred to as Potential Evapotranspiration (PET), is an estimate of water requirement for a well watered reference crop. This reference crop (grass or alfalfa) is essentially an idealized crop used as a basis for the ET model. Reference ET is calculated by applying climate data (temperature, solar radiation, wind, humidity) in a model (equation). It is helpful to note that reference ET is only an estimate of the water demand for this idealized crop, based upon weather station data at a given location. The Texas High Plains ET Network uses an idealized grass reference crop.

 

How is estimated ET used to schedule irrigation?

There are a variety of irrigation scheduling methods, models and tools available. Many are essentially based upon a "checkbook" approach: Water stored in the soil (in the crop's root zone) is withdrawn by evapotranspiration and deposited back into the soil through precipitation and irrigation. When soil moisture storage falls below a given threshold value, irrigation should be applied to restore the moisture. The threshold value may be determined by crop drought sensitivity, by irrigation system capabilities, or other farm-level criteria.

For agricultural producers, this information can be used to help them make informed choices on when and how often to water their crops.  For the homeowner, it provides a useful tool to calculate when and how much to water their lawn.  Watering the landscape more efficiently not only reduces waste of our groundwater, but also reduces water bills during the hot summer months to come.

The evapotranspiration data and much more is available on the TXHPET Network website.  There is a useful user's guide that thoroughly explains the information to be found on the website and how to use it.  By clicking on the "weather data" tab, the user can select whether they would like daily or hourly information, and then can select the station closest to their location to most closely approximate their ET.  Users should select a location from the drop down menu and click "add", then select the type of data that they would like to see and click "add" again to choose that data set.  You can then select whether you would like to view the data as a graph or as a table, and users will find the information both educational and highly useful in planning for either crop or turf irrigation.

To learn how to use the TXHPET Network to schedule your lawn watering, which will both conserve our precious groundwater and save you money, please visit the "Lawn Irrigation Planning Using the TXHPET Network" page.