Urban Water Interests and Rural Watersheds

by Mike Mecke

Former San Antonio Water System Employee

and Former Vice President, Bexar Audubon Society

(Technical Paper given Dec. 5, 2000, at National Grazing Lands Initiative Conference, Las Vegas, Nevada)

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 also increase 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.

Urban residents also have a vested interest and concern with improved wildlife habitat in Texas and other states as many are hunters, fishermen, wildlife watchers or campers who certainly benefit greatly from properly planned and executed brush management.

While 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 and Uvalde Agricultural Experiment Stations and demonstrations at the famous Seco Creek Water Quality Project have shown that potential water yield can be greatly increased by selective brush removal, but these studies were not on large-scale watersheds.

Are these results applicable to larger watersheds? If so, which watersheds, what slopes, what type of shrub species mix and how many of the less desirable plants can be removed without harming species such as deer? What types of brush management patterns would be best on which sites?

When is grass and forb reseeding required? This is not always an easy question in this ecoregion, as often apparently grass-denuded sites will recover fairly quickly when the shrub cover is reduced and the pasture rested. This has seemed especially true when treated with prescribed burning. Other cases do not respond well and reseeding may be required, which greatly increases the costs and intensifies the management.

Deferment prior to treatment may be required to accurately assess the composition of the herbaceous plant community and to be able to estimate whether enough desirable plants are still present. And, if you have a dry summer, there may not be much grass growth even with a rest!

Historically much off 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 resources, producing the thousands of springs, creeks and clear flowing rivers of this limestone region.

During the past 150 years the area has largely become an oak-juniper woodland with many dry springs and infrequently flowing creeks. The selective control of cedar (actually a juniper, Juniperus ashei) on the watersheds of the rivers and creeks which recharge the Edwards Aquifer is a very positive management practice. The San Antonio Water System, other local water resource groups and both state and federal agencies are very seriously evaluating it.

As the practice is very expensive in most cases and will have to be carried out on private ranches, actual broad-scale implementation may be years away. Also, additional research is needed in order to assure efficiency in achieving the greatest returns to landowners, downstream water users, and wildlife resources and to the funding agencies.

Potentially, this watershed management practice could greatly increase both local groundwater supplies on the Edwards and the recharge from streamflow across the porous, faulted limestone of the Edwards Aquifer Recharge Zone. The past, pre-European-man vegetation of the region is greatly different from the dominant oak/juniper woodlands now covering most of the region. The increased water use by woody species and lowered soil infiltration has reduced many of the once-perennial creeks to dry, intermittent streambeds, thus causing recharge to aquifers to drop significantly.

The most valuable product of rangelands is pure water. So, ideally rangelands should be managed not only to provide livestock forage, wildlife habitat, and recreational opportunities but most of all, to produce sufficient quantities of clean water throughout the watersheds. This is the water which maintains creek and river flows and recharges aquifers. If rangelands become infested with heavy water-utilizing shrubs and trees, they soon lose the beneficial watershed characteristics so desired by hydrologists.

One of the principal net effects of this woody plant invasion coupled with the decrease in herbaceous vegetation, is that less water is available to replenish the invaluable Edwards Aquifer — especially during dry years, when little rain runoff is available for groundwater recharge.

This is perhaps the effect which should be of most concern to not only to the urban users and industry, but also to agricultural irrigators, ranchers, wildlife biologists, downstream water users and the Federal courts which are now protecting the endangered species living in several large area springs.

Complicating the serious present concerns about the Edwards Aquifer's quality and quantity of water are the Texas Water Development Board's projections for state municipal and industrial water demands to increase by 186 percent by 2040.

Present Research Situation

On several small watersheds near Sonora and Uvalde (Edwards Aquifer Recharge Zone), personnel from both the Texas A & M University System and the USDA’s Natural Resource Conservation Service (NRCS) have effectively demonstrated the positive impact of selective brush management and grazing management on both water quality and quantity.

As these studies were conducted on small areas (5 to 20 acres), some observers are not convinced that the results are applicable on large land tracts elsewhere on the Edwards Plateau. Extrapolation of results from small sites to programs of watershed and landscape scale can be potentially dangerous and very expensive if incorrect.

Similar results have been obtained across Texas and the rest of the Southwest, in treating juniper, pinon pine, oak shinnery, mesquite and other brush species, by both USDA and privately financed-range management programs. But, unfortunately, there is little information in the Texas watershed research database to provide convincing evidence of the hydrologic values of various brush-control and grazing-management practices, especially those combined with the use of prescribed fire on juniper on the southern Edwards Plateau.

Watershed studies are by nature long-term. Five years is a minimal length for good data, especially in the Southwest or West where precipitation is highly variable and drought is a regular visitor.

It is clearly in the interest of urban and rural residents to encourage and promote the research needed to wisely manage and treat rural watersheds in order to facilitate increased aquifer recharge with sustained, adequate steamflows in area creeks and rivers for wildlife, fisheries and Gulf estuary needs.

Research in other regions also provides certain benefits, which complement much-needed Edwards-region studies. The overall economic health of the region is likewise critical to large cities’ economy and future. For instance, Bexar County, home to San Antonio, rates agricultural sales and production as the third most important economic industry. So, while rural areas depend upon cities for their needs and markets, the cities also need the rural areas’ contributions to their economies. And, they certainly need a sustainable supply of clean fresh water from rural areas!

Once research has obtained the needed facts determining optimal watershed treatment-site locations, methodology, and the downstream-user water-supply benefits, then large-scale funding will be necessary in order to carry out watershed-management programs of this magnitude. Proper water conservation, management and development techniques will be critical to meeting the future water needs of a rapidly growing urban population across Texas. And probably most other Southwestern and Western states as well!

San Antonio Water System has approved partial funding of watershed studies by the NRCS, the Edwards Aquifer Authority, U.S. Geological Survey, and Texas Parks & Wildlife Department on two state parks in central Texas. This utility has also partnered in rainfall interception and modeling studies on juniper sites carried out by Texas A & M University. More comprehensive studies will require funding from state sources, federal programs and urban water interests to accurately assess the benefits which are equally important to agricultural producers and their communities.

SUMMARY

I believe that in all cases, just as with NRCS’ Great Plains Program, very strict management guidelines must be in the long-term contract. Cost-benefit analysis, range deferment, proper grazing use, wildlife management and appropriate grazing systems must be major components of all public watershed-treatment programs in order to assure good natural-resource conservation and restoration results. Wording in such contracts must be clear and precise and state that all contracts will be monitored and those in major violation will be required to pay back all public funds expended on their property. Regular, as-needed brush maintenance must also be part of these contracts in order to maintain the desired tree, shrub and herbaceous composition. If cost-share money is used, then the proper conservation and long-term management must go with it — period! We in public agencies have an obligation not only to promote and practice good conservation and sustainable agriculture, but we must also see that public funds are wisely used. Brush management without deferment and good range management is not wise use.

Such programs are doomed to fail, I believe, and eventually will cause a loss of faith both in our agencies and in agricultural producers. We have the necessary range science skills required to successfully carry out these watershed management BMP’s, but they must be included in the watershed planner’s kits and always be a part of the execution of these contracts. There will still be some cases of failure, but they will be mostly due to weather extremes, operator error or other minor problems. Good science must rule over politics or expediency.

A general statement for any group contemplating brush management BMP’s on a watershed for water-resource development to consider: personally, I would like to see any and all of these projects under long-term contracts labeled and always described as "watershed management projects." If a major goal or objective is water yields or water quality, then clearly all participants should understand it, and the media and the public should understand that their tax- or rate-supported dollars are being spent for watershed management — not the brush control practices we have carried out for decades as a range-management BMP.

When discussing the watershed management BMP we all need to get this language in our literature, also in our every-day "talking vocabulary," and for sure in our meetings. This is actually what these practices are intended to be and why public monies are funding them. It will aid in the education of both the rural and urban public to emphasize that watershed management or renovation or planning with a "Brush Management BMP" is being done primarily to improve watershed yields and water quality. Livestock, wildlife and recreation benefits certainly will occur with proper planning and implementation, but are secondary to water in these projects.

That needs to be learned and thoroughly understood by all concerned — including the media, conservation groups, the ranchers or landowners and the public who are paying most of the costs.

Sure, these other issues and benefits affect our planning, but they are not the primary goal in these cases. This is not the old-fashioned "brush control" for livestock forage and range management that we have carried out for decades and the distinction needs to be clear in everybody's mind. We have been extremely neglectful of rural and urban watersheds, their research needs and management in Texas and are behind the curve — maybe it is time to start catching up? Better late than never!

Sure, the water resources are largely in the rural regions, but remember the markets, much of the needed funding and the votes are in the cities! So, we all need each other and we need to cooperate on all fronts as friends, neighbors and business partners in order to have a sustainable America.