The people of this region have depended on the Edwards Aquifer for hundreds of years. Until recently, the aquifer water has been pure, but that is changing. We are now detecting man-made contaminants in our aquifer. In the great majority of cases, contaminant concentrations are low — well below the limits that have been established to protect human health. Thus, this degradation of water quality is not cause for alarm, but it is something we should be concerned about.
Most of the degradation is caused by the urbanization of vulnerable portions of the aquifer: the recharge zone, transition zone, and near-by portions of the contributing zone. More urbanization results in more degradation. The degree of urbanization in an area can be measured by the percentage of impervious cover. That is, the percentage of land covered by features such as streets, parking lots, and buildings.
As streams flow through urbanized areas, they pick up contaminants such as pesticides, solvents, metals, and fecal bacteria. When these streams flow across the recharge zone, the stream water and the contaminants it is carrying enter the aquifer to become part of our drinking water supply.
The Board of the Edwards Aquifer Authority is concerned about the degradation of water quality and is working to protect our aquifer. Over the past year it has been developing rules to limit the construction of impervious cover. As contemplated, the rules would have limited impervious cover over the recharge zone, and the contributing zone within five miles of the recharge zone, to 20 percent, with an additional 10 percent allowed if certain measures were taken to protect water quality.
Needless to say, the development community did not like what the EAA was proposing to do. In response, they called on some members of the State Legislature to growl their disapproval to the EAA: Senator Jeff Wentworth (R - San Antonio), Representative Ed Kuempel (R - Seguin), and Representative Doug Miller (R - New Braunfels). Faced with this pressure, the EAA abandoned its work on impervious cover limits.
However, the EAA is not giving up on protecting water quality. Instead of impervious cover limits, it is hoping that engineered systems, known as Best Management Practices (BMPs), will remove the contaminants produced by urbanization before they find their way into the aquifer. BMPs include sand filters, detention ponds, and vegetated filter strips. The problem with BMPs is that sometimes they work and sometimes they don’t. It is difficult, if not impossible, to know in advance whether a BMP is going to work as intended. Therefore, it is essential that the EAA designs and administers the best possible BMP program. Such a program would include stringent limits on contaminant concentrations, monitoring requirements to ensure that BMPs are operating as intended, and meaningful penalties for violations.
In pushing the EAA to back off of impervious cover limits, the development community has won a significant victory. Still, many developers will continue to oppose any aquifer protection program that interferes with business as usual, or costs them additional money. Therefore, they are likely to work to ensure that any BMP program enacted by the EAA is ineffectual. That is, they will only accept a program with lax limits on contaminant concentrations, weak monitoring requirements, and penalties that are no more than a slap on the wrist. So once again, they may sic Jeff, Ed, and Doug on the EAA. And once again, the Board of the EAA may buckle under the pressure. But let’s hope not. The people of this region deserve better. Stay tuned. •
George Rice is a groundwater hydrologist and the EAA’s District 3 board member.
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