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Study indicates nitrate levels on the rise in Barton Creek watershed

Thursday, July 28, 2011 by Elizabeth Pagano

Nitrate levels are rising in Barton Springs, but the problem’s cause – and solution –remains unclear.


A recent study conducted by the City of Austin in cooperation with other local agencies and the U.S. Geologic Survey, shows that nitrate levels in Barton Springs and five streams that recharge it are much higher than in 2005. In some places, nitrate concentrations are six to ten times greater than they were in 2008.


Increased nitrates in water are a concern, as excessive concentrations can cause algae growth. When the algae then die and decompose, they consume oxygen in the water, making it less able to support other life, such as fish and salamanders.


“We don’t know where the nitrogen is coming from, which makes mitigating that, or solving the problems of increased nutrients all that more difficult” said the Watershed Protection Department’s Chris Herrington, who is one of the study’s authors, in a presentation to the Environmental Board.


While the exact origin of the nitrates may be unknown, the most likely culprit is thought to be of a biogenic source, which could include pet waste, manure, or wastewater that is derived from human waste.


It is wastewater which is of the greatest concern to Herrington, who hopes that the data collected from the study can be used to modify existing rules which aid the Texas Commission on Environmental Quality (TCEQ) in granting permits for wastewater disposal. Disposal takes place either in the form of direct discharge into creeks—which Herrington explained as “the worst possible option for water quality”—or land application of wastewater.


Because the Austin area only has one direct discharge permit, which was not being used at the time of the study, it would appear that the land application process is not effectively filtering out nitrates.


“That’s not supposed to be happening. What we’re really trying to do is, one, prove that is happening, two, find out why it’s happening so we can figure out a way to change how effluent is applied to make sure that doesn’t happen,” Herrington told In Fact Daily.


Herrington continued, “We may want to apply less, we may want to apply further away from critical environmental features, those are things we would have to change in the rules. And we want to do it as a holistic measure, and try to incorporate the development community. There may be things that they want to change that we would be OK with – that would not impact water quality in a bad way.”


Bill Bunch, executive director of the Save Our Springs Alliance, told In Fact Daily that his organization was currently trying to “get a handle” on existing wastewater irrigation facilities. “There’s too many of them out there already,” said Bunch,


“They are permitted as no-discharge facilities, and what we are seeing, more often than not, is that they are functioning as indirect discharge facilities,” said Bunch. “The work we’ve been doing has been focusing on connecting back to the rules, and where the shortcomings are in the rules that are leading to these impacts that we’re seeing.”


Changing the rules would involve taking data to the state, and working through the legislature. Currently, there is no local authority to regulate wastewater permits. Though the city has the opportunity to protest decisions by the TCEQ, the agency is under no obligation to honor those protests.


In 2008, after a long fight, the TCEQ gave a Hays County development called Belterra a direct discharge permit. The agency acted over the objections of the city, and the recommendation of a judge. In the end, the issuance of permits rests solely on the commissioners’ judgment. The commission also declined to enact rules that would protect Barton and Onion Creeks from direct discharge of pollutants.


“It’s an uncertain process. What we want to do is develop better rules so there is certainty for the applicant and for folks like us that are concerned of the impact,” said Herrington. “This study is important in a couple different ways. Relative to our long-range plan of trying to see if there is a better way to do these land-application permits, this study is a very important first step.”

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