Watershed group updates Council on groundwater issues

Last week, Council members heard a scheduled six-month update on various groundwater issues related to impervious cover and subsurface structures.

 

“During discussions of the amendment, concerns were raised regarding groundwater impacts,” said Jose Guerrero of the Watershed Protection Department. He noted that the presentation was a follow-up to concerns raised by Council in 2008.

 

Guerrero then proceeded to illustrate a handful of advances in the way that the city thinks and acts regarding groundwater.

 

A revamped “One Stop Shop” was included in the new regimen. In response to the Council’s requests, reviewers there now assume that all subsurface structures will encounter groundwater. They’ve also equipped themselves with an “alluvial groundwater map” to better pinpoint the locations of groundwater in the urban core and an improved review process that “addresses groundwater presence, groundwater quantity, groundwater quantity, and groundwater disposal.”

 

Guerrero also noted that staff is evaluating the benefits of reintroducing this groundwater into creeks, adding that, “infiltration (as the process is called)…is currently allowed” but that “we just don’t have any standards at this time.”

 

Along the way, he pointed to three case studies to illustrate successful examples of current city groundwater-related initiatives. The first of these can be found at the Tarrytown United Methodist Church’s parking garage, where the city of Austin gave the facility $5,000 to “install underground storage tanks to capture and reuse the groundwater” that “began pouring” into the site. The second was the potential groundwater contamination clean up that had resulted from a dry cleaning chemical leak from a private sewer line.

 

He used his third case study to show the positive results of a public-private partnership that had led to the refitting of a groundwater-troubled section of Pearl Street in the University Neighborhood Overlay (UNO) district. Guerrero had singled out the UNO district as a place where Council targeted dense development with increases in impervious cover.

 

It came up as part of his discussion about the establishment of Public Improvement Districts. He noted that this sort of arrangement, which would allow for “city authorized funding of groundwater infrastructure,” could be “challenging” because it would require significant landowner participation. 

 

The most startling moment of Guerrero’s presentation came when he unveiled a map that illustrated potential groundwater contamination sites. On it, 800 potential locations of underground containment tanks were marked with red dots. Guerrero noted that of the 400 examined thus far, only three were still present. This was likely the result of the fact that staff had used historical Texas Commission on Environmental Quality data to assemble the map.

 

Pat Murphy of WPD later told In Fact Daily that “the map is a tool” but that his department is somewhat wary of the information in it.

 

“What we don’t want is that tool to be used as saying that there absolutely is a contamination site here,” he said. “This is just historic data to say we believe there was a contaminated site near you and you should consider that with groundwater.”

 

Murphy broke the report down into four main points. He highlighted the department’s efforts in “addressing groundwater as it relates to subsurface pumpage that creates surface run-off.” To that, he added that his department is also “looking at the quantity of that water, trying to make sure that it goes safely to its destination” and “alternative ways of disposing of that and reusing that groundwater rather than sending it to the creeks.”

 

He closed by noting that his department is “also mindful of and monitoring potential groundwater contamination that might be discharged as surface water to our creeks.”