Our reliance on water for agriculture and household usage has been very prevalent during the past few years of which some part if not all of the state has been stricken with severe drought conditions. Combine with the increase in the state’s population and the desire to maintain water-dependent landscapes, the demand is going to be more than the watershed can provide.
Texas has more than 191,000 miles of rivers and almost 2 million acres of lakes and sits on top of two of the largest aquifers in the nation, the Ogallala and the Edwards. So what does Texas rangelands have to do with any of this?
Rangelands, grasslands, shrub-lands, marshes, deserts and woodlands account for about 60% of Texas’ land area. These rangelands support livestock production as well as habitat for native wildlife, but most importantly they serve as the state’s watershed.
Most of Texas’ water supply comes from captured surface sources such as lakes and ponds or is pumped from underground aquifers, both are dependent on precipitation that falls on rangeland so that re-charging can take place. These areas have an impact on the quantity and quality of water on which we depend.
It is estimated that in an average rainfall year about 42% of precipitation evaporates into the atmosphere and 47% is lost through plant transpiration and only 1% re-charges the aquifers and the remaining 10% runs down stream.
Rangeland vegetation influences the amount of water that evaporates, infiltrates and runs off. Researches have found that with 60% ground cover, run off can be kept to 5%, thus protecting water quality. Ground vegetation filters sediment particles in which pesticides, nutrients and other pollutants bind to, therefore preserving water quality.
As human populations grow, so do the number of homes and roads to connect them; reducing the amount of open land available to absorb precious rainfall while limiting natures filtering system and avenues to re-charge our aquifers. It is estimated that at the current rate of water extraction from the Edwards aquifer compared to the recharge rate all potable water from this source, will be depleted in 25 years, unless conservation measures are implemented or extraction is restricted by some means.
Fortunately due to the efforts of our forefathers there are millions of acres of rangeland protected from development and misuse, but will it be enough to sustain us with the quality of live we have become accustom to or will there be other resolutions to be made?
Eddie Baggs, Denton County Extension Agent-Agriculture
Texas AgriLife Extension – Denton County
(940) 349-2880 or Metro (972) 434-8812