Bandera and other surrounding counties help recharge the Edwards Aquifer where more land is needed to secure conservation of one of Texas' largest water sources and serves approximately two million people. Credit: Bonnie Arbittier / Rivard Report

The total Edwards Aquifer watershed north of San Antonio is 2.5 million acres, composed of 2 million acres in the Contributing Zone and 500,000 acres in the Recharge Zone. To protect the total watershed, we must protect land and water in both zones, not just one of them.

In a 2018 report, the Edwards Aquifer Authority suggested protecting 200,000 acres in the Contributing Zone within 5 miles of the recharge zone and 194,000 acres of Contributing Zone made up of land lying within 1,000 feet of streams within 10 miles of the Recharge Zone. These suggestions are in addition to protecting the Recharge Zone. This sensitive acreage needs protection because 80 percent of the rain recharging the Edwards Aquifer falls in the catchment (contributing) area of the watershed. 

The City of San Antonio’s consultant, LMI, hired to assess the Edwards Aquifer Protection Program, agrees that the Contributing Zone must be protected. The LMI report states: “The importance of the contributing zone to water quantity and quality cannot be overstated. Land use practices in the contributing zone that interrupt surface water flow with impervious surface or intercept surface water flow by impoundment would change the amount of water available to the recharge zone and could drastically diminish aquifer recharge.” The report goes on to explain that “equally important in protecting water quality in the Recharge Zone is the protection of stream-water quality in the contributing zone, as most of the Edwards Aquifer water originates from streams in the contributing zone.”

But, because of an inaccurate metric in the LMI report, some City officials thought we could completely protect the water quality and Edwards Aquifer withdrawal permits by protecting acreage in the Recharge Zone, ignoring the Contributing Zone. This metric only applied to protection in the Recharge Zone, not the total watershed. It assumed that securing an easement for 1 acre of land in the Recharge Zone protected 1.1 acre-feet per year of Edwards pumping permit. It ignored the Contributing Zone. The result was a plan to end the program completely when only about 9 percent of the total watershed had been protected with conservation easements. The many geologists we know all disagree. It’s not a close question.

To understand how much total watershed protection is needed, both EAA and LMI suggest looking to the New York City watershed protection program as an appropriate model for setting protection standards for the Edwards Aquifer. The 40 percent watershed protection standard of New York City could be a long-term goal.  The more modest 22 percent achievement of the Chesapeake Bay Compact is also referenced by EAA as a comparable watershed, and could serve as an interim goal. 

So far, the EAPP has only protected 7 percent of the watershed, buying conservation easements and land totaling 150,000 acres in the Recharge Zone and 13,000 acres in the Contributing Zone. The Contributing Zone is less than 1 percent protected by the EAPP.  

We need to complete the program by including much more of the Contributing Zone. We aren’t protected if we shut down the program after purchasing 2 percent more of the watershed that lies only in the Recharge Zone. 

Approximately half of the present one-eighth cent sales tax for aquifer protection and linear parks is presently dedicated to aquifer protection. That means it would take only a one-sixteenth cent sales tax to continue the present level of funding for aquifer protection, raising $20 million a year. The funding for linear parks could be provided by alternative funding. The City staff briefing suggests that the funding could come from Bexar County. The Linear Park Advisory Board prefers that its funding be provided by continuing the one-eighth cent sales tax. 

At present, the City has no proposal for continuing the present level of funding for aquifer protection. Instead, City staff presented council with a choice of a 48-percent reduction in funding of $52 million from SAWS for five years, or a 45-percent reduction of $109 million over 10 years, using “self-supporting debt.”  That doesn’t work. 

First, to take into account inflation in real estate values, the upfront financing would have to cover $254 million for a 10-year program, not $109 million.  This is because the cost of real estate easement purchases are increasing at a 5 percent per year compound rate, according to LMI. Second, that option has financing costs that the sales tax option does not incur. Financing costs include bond counsel and tens of millions of dollars of interest charges on the debt. Interest could be avoided by funding with the sales tax. Third, and most importantly, that debt financing option may have mistakenly been proposed as a way to end the EAPP after 10 years, when the EAPP must continue and acquire substantial easement protection in the Contributing Zone as discussed above.

Therefore, we are recommending that an option be put before the city council to continue the EAPP at its present level of funding by allowing the voters to vote on a one-sixteenth cent sales tax five-year extension, renewable with voter approval in the future. To  put this on the table, there needs to be a briefing of that option to the city council. Or, the one-eighth cent sales tax for both aquifer protection and linear parks could be submitted to the voters and renewed for another 5 years, with more such voting opportunities renewable in the future. Either sales tax approach could work, and the EAA is always ready to provide expertise to city council, if requested. 

Carol Patterson

Carol Patterson

Carol Patterson graduated from Reed College and has served San Antonio on the Board of the Edwards Aquifer Authority since 1996, and the prior Edwards Underground Water District from 1991-1996. She...

Kirk Patterson

Kirk Patterson

Kirk Patterson received his BA in math and Economics, a JD from Harvard Law school, clerked for the Texas Supreme Court, and practiced appellate law in San Antonio until his retirement.