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A Briarpatch

or a Diverse Habitat with Water

by Mike Mecke

Former San Antonio Water System Employee

and Former Vice President, Bexar Audubon Society

Historically the drainage area of the Edwards Aquifer region was a grassland savannah, with mid and tall grasses interspersed with scattered stands of various brush and tree species. 

This was highly productive range for wildlife, livestock and for water issuing from the limestone, which maintained the thousands of springs, creeks and clear flowing rivers of this region.  During the past 150 years the area has largely become an oak-juniper woodland with many dry springs and infrequently flowing streams.

This has reduced natural recharge to the Edwards Aquifer and to other more shallow aquifers in the region such as the Trinity-Edwards.  Diaries from the Spanish explorers confirm what 19^th-century early botanists also described -- the present state of the vegetation on the Edwards Plateau (and many other regions) is not anywhere close to it's natural pre-European condition. 

This can also be confirmed by aerial photos only going back 20 to 60 years in areas where juniper or "cedar" has greatly increased.  Several factors are thought to have brought about this rapid deterioration in rangeland habitat such as over-grazing by livestock, old European grazing systems not suited for Southwestern ranges, the control of wildfires; crossfencing  preventing natural grazing animal movements to fresh pastures, and the aggravating effects of several severe droughts in the 1900's. The lack of fire in this ecosystem has been especially kind to cedar and some other shrub species that are very fire sensitive.

Brush management on watersheds to increase water yields is not a new idea. For over 30 years studies in Texas, Arizona, California and other states have proven that carefully planned removal of certain brushy plant species can not only improve rangelands for livestock grazing, but increases the water production in streams and in aquifers, while removing sediment and other pollutants. If properly planned and operated, such programs have also improved wildlife habitat and even increased certain endangered species such as the black-capped vireo at the Kerr Wildlife Management Area.

While the application of this watershed management principle is a proven fact, many of the controlling factors on certain types of watersheds in Texas are either unknown or in open question. Most of the prior studies regarding brush management in Texas have focused on the range management and livestock production benefits. In recent years research at Sonora, Seco Creek and Uvalde has proven that potential water yield can be greatly increased by selective brush removal, but studies were not on large-scale watersheds. Other studies or sources have provided results that have been clearly visible, but not scientifically based or quantified.  Are these results applicable to larger watersheds such as that of our Edwards Aquifer? I feel that they are.

It is in the interest of the region to encourage, support and promote the research needed to wisely manage the watersheds draining across the Edwards Aquifer Recharge Zone in order to facilitate increased recharge to the aquifer. A stable watershed yield would be beneficial in maintaining adequate steamflows in area creeks and rivers for wildlife, fisheries and downstream bay/estuary needs. 

Remember a few years ago, when the Blanco River dried up? The people of Blanco do. In the drought of the 50s many area streams dried up, including the Medina River. The major drought which started in 1947 and extended until 1957 completely dried up the famous Comal Springs in New Braunfels. And, that drought occurred prior to most irrigation well drilling into the Edwards Aquifer and before San Antonio became a city of one million plus! What would be the situation now in a similar long-term catastrophe? Would large, lush green lawns or golf courses still be a high priority? Or would the production of food and drinking water rule? 

Agriculture is the #2 industry in Texas and the overall economic health of the agricultural community is likewise critical to San Antonio's economy and future. Agriculture benefits heavily from improved watershed management accompanied by a strong range management system and proper utilization of our stream riparian zones. Not only can ranchers on a healthy rangeland watershed carry more livestock, but also stock has a higher quality diet and the ease of moving and checking their animals is greatly improved. A high level of the Edwards Aquifer promotes a healthy irrigated agriculture that is key to not only regional economics, but to producing the food, fiber and other crops that we now buy so cheaply compared to other nations. Not to mention keeping regional towns and communities alive and thriving so that they can trade with neighbors in San Antonio or other cities.

Riparian zones, essentially the green areas along streams, rivers or other water bodies, are very necessary to maintaining quality wildlife habitat, a healthy aquatic community and clean water in our rivers and lakes. Healthy riparian zones vibrant with the native grasses, aquatic plants, shrubs and trees, act as living filters to remove pollutants and sediments which also aids in keeping reservoirs pure. When healthy, riparian areas act as sponges absorbing and storing water that is later slowly released during drier periods, thus maintaining stream flows and aiding in drought management.

Downstream urban interests gain by having a steady release of clean, pure water to aquifers, rivers, and lakes.  Bays and estuaries are then provided a pure and more constant supply of water to nourish the valuable shellfish, shrimp and fishing resources of our state.

Wildlife habitat that is healthy and diverse produces another crop for agricultural landowners, whether that be via a hunting lease, fishing fees or other forms of eco-tourism such as hiking, camping, birding and wildlife viewing.   Property values rise for the wise landowner and a healthy tax base is maintained for our society.

So, it is easy to see that the bottom line is a healthy watershed and riparian zone is a win-win proposition for all!   Do your part - become involved or at least become a knowledgeable citizen voter!