How discharged wastewater is feeding massive Hill Country algae blooms

Hill Country
Algae bloom in South San Gabriel River downstream of the Liberty Hill wastewater plant (Courtesy Save Barton Creek Association)

Algae bloom in South San Gabriel River downstream of the Liberty Hill wastewater plant (Courtesy Save Barton Creek Association)

AUSTIN (KXAN) — Green mats coat what once were clear, scenic creeks and rivers, the result of algae blooms that are frustrating those who live in the Texas Hill Country.

Effluent is wastewater with its pollutants removed, also known as treated wastewater. When effluent is discharged into creeks in the Hill Country, they experience massive algae blooms, specifically a type called Cladophora glomerata, which attaches to creek beds instead of floating on top of the water like the blue-green algae found in Lady Bird Lake.

Communities that live near these creeks and treasure them are fighting against developers who want approval for wastewater discharge permits for their projects.

One battle happened earlier this year when a developer wanted a wastewater discharge permit for his land, so it would be more attractive to potential buyers. His plot of land was near Polo Club in Hays County, and the wastewater discharge permit would allow effluent to flow into Long Branch Creek.

Residents of the Polo Club and other nearby neighborhoods protested this possible wastewater discharge permit.

“I don’t oppose the development but, like my neighbors, I oppose this permit, because the analysis by the TCEQ is flawed, and multiple scientific studies indicate that there will be degradation of the water quality upstream of Barton Creek,” explained Dr. Kim Rouge, who is a landowner in the Polo Club.

This comment reflects the sentiments of several people who spoke at a TCEQ hearing several months ago – they don’t oppose development and don’t want to stunt business expansion, but they aren’t willing to sacrifice their creeks in the name of growth.

This specific hearing ended with the developer choosing not to pursue a wastewater discharge permit. But the Hill Country continues to see rapid growth and high demand for development, which will likely lead to more permit requests.

Relationship between wastewater discharge and algae blooms

Brian Zabcik, the wastewater campaign organizer for the Save Barton Creek Association, said while these algae blooms in the Hill Country do not produce toxins, they do damage the ecosystems of the creeks and streams where they appear.

“When you coat the creek or river with thick mats of algae, which basically looks like sick, huge masses of wet green yarn, it’s impossible to do anything in the stream or underneath in the water. And so, you’re harming the wildlife that is there. You’re harming the fish populations,” Zabcik explained.

Algae bloom in South San Gabriel River downstream of the Liberty Hill wastewater plant (Courtesy Save Barton Creek Association)
Algae bloom in South San Gabriel River downstream of the Liberty Hill wastewater plant (Courtesy Save Barton Creek Association)

Chris Herrington, who was the environmental officer for the City of Austin up to the beginning of July of this year, explained why the Hill Country creeks are conducive to these algae blooms.

“It’s a perfect laboratory or perfect growing environment for algae, because the rock is the place for the algae to attach and stay in one place, and then the water will bring the nutrients, the food for the algae, and the sunlight can go all the way down to the bottom where that algae is, because the water is so clear,” he said.

According to Herrington, while high levels of nitrogen and phosphorus are not naturally found in these creeks, the effluent from wastewater discharge plants contains these nutrients. When effluent is introduced into the creeks, it provides food for the algae, allowing it to bloom. When there is no nitrogen and phosphorus introduced, there is no bloom.

“The problem is, when you introduce wastewater into those Edwards plateau systems, now you’ve got this perfect environment to grow algae, and the only thing that was stopping it was [the lack of] nitrogen and phosphorus. Even highly treated wastewater, its nitrogen and phosphorus are orders of magnitude higher than what occurs naturally in those [Hill Country creeks’] soils. And so now you just put food into this place, and that’s why we see these dramatic impacts,” Herrington summarized in his interview.

Left: A photo from 2019 shows an algae bloom in the Blanco River. Right: The algae bloom has cleared in this 2020 photo after the City of Blanco stopped discharging effluent into the river (Courtesy Save our Springs Alliance)
Left: A photo from 2019 shows an algae bloom in the Blanco River. Right: The algae bloom has cleared in this 2020 photo after the City of Blanco stopped discharging effluent into the river (Courtesy Save our Springs Alliance)

Geographic differences affect algae blooms  

To protect Hill Country creeks, organizations such as the Save Barton Creek Association believe wastewater discharge permits, issued by the Texas Commission on Environmental Quality, or TCEQ, need to be changed to include the contributing zone of the Edwards Aquifer, which falls in the Edwards Plateau geographic region. Currently, TCEQ permits only protect the recharge zone.

“Hays County has beautiful streams, but they’re fragile, and we’re very concerned discharge is being introduced on streams that we don’t believe can handle it,” Zabcik said.

The contributing zone of the Edwards Aquifer is all the watersheds that feed runoff into rivers and streams that flow over the recharge zone. The recharge zone is where water on the surface can infiltrate the aquifer through fissures, caves and other openings.  

There is a fundamental difference between the creeks found in the Edwards Plateau geographic region and the creeks found in the Blackland Prairie geographic region.

In the Austin area, the approximate dividing line between these two regions is Interstate 35, with the Edwards Plateau west of the highway and the Blackland Prairie to the east.

According to Herrington, creeks in the Edwards Plateau are characterized by a solid rock bottom, clear water due to “very thin and very poor quality” soils and extremely low levels of nutrients. On the other hand, Blackland Prairie creeks are characterized by sandy clay bottoms, murkier water due to the vegetation and the depth of soil present, and naturally higher levels of nutrients.

Due to these differences, Herrington explained creeks in the Edwards Plateau have an extreme reaction, such as algae blooms, to effluent, while Blackland Prairie creeks are “radically different and the impact is much less.”  

Impact of TCEQ permits

TCEQ permits should consider that “conditions vary wildly across the state,” when issuing wastewater discharge permits, Herrington said.

According to a media representative at the TCEQ, “the TCEQ takes into account regional and site-specific factors when developing regulations and in implementing the regulations.”  

Another issue which Herrington and Zabcik both explained was wastewater discharge permits are prohibited in the recharge zone of the Edwards Aquifer but not the contributing zone.

The contributing zone is about 5,400 square miles. The only part of the 5,400 miles which is regulated is on the boundary of the contributing zone and the recharge zone.

According to Title 30, Chapter 213.6 of the Texas Administrative Code (TAC), from zero-to-five miles upstream of the recharge zone the limits for nitrogen and phosphorus in effluent are: “(C) two milligrams per liter of ammonia nitrogen, based on a 30-day average; (D) one milligram per liter of phosphorus, based on a 30-day average.”

Similar nitrogen and phosphorus limits are given for five-to-10 miles upstream of the recharge zone.

This means that effluent’s nitrogen and phosphorus levels are regulated up to 10 miles outside of the recharge zone – as long as it is upstream of the recharge zone, not downstream.

“One of the most illogical disconnects is over the recharge zone. Under state rules, discharges are prohibited [in the recharge zone] but not in the contributing zone, and that water goes into the recharge zone.” Herrington elaborated, “where water literally goes into the aquifer, the quality of that water is driven entirely by the quality of water in the contributing zone – the upstream streams where that water is coming from – but TCEQ rules don’t prohibit discharges in the contributing zone.”

Therefore, according to Herrington, not only are creeks in the contributing zone being affected by algae blooms due to effluent discharge in the Hill Country, but eventually, this water will affect the recharge zone of the aquifer.

KXAN asked the TCEQ about the factors determining where certain permits are allowed, and it directed us to the 21st volume of the Texas Register which was published in 1996.

On page 12133 of the Register, it addresses the potential for extending the regulations for protecting water quality to the entire contributing zone:

“The commission is concerned that the economic impact on state government and on those subject to compliance with the regulation for extending regulation to this area [the entire contributing zone] may be substantial, and, thus, require a substantial and thorough, scientific demonstration that the measures and geographic scope will provide a significant increase in water quality protection,” it said. “There is currently insufficient information on which to base decisions about the type of activities that need to be regulated, the scope of regulatory efforts and the most appropriate geographic area for regulation.”

Zabcik also pointed out the TCEQ regulates oxygen levels, solids and E. coli levels in effluent but not the nitrogen and phosphorus levels for creeks in the contributing zone.

“TCEQ doesn’t know what is good or bad. It’s just a qualitative judgment. And so, literally, the law says that they can’t issue a permit that lowers water quality by more than a de minimis amount, but nowhere is de minimis defined,” Herrington explained.

KXAN could not find a place where “de minimus” is defined. However, there is a caveat.

The TCEQ document, Procedures to Implement the Texas Surface Water Quality Standards, outlines how the TCEQ conducts antidegradation reviews to ensure a “higher level of water quality” is maintained. It allows for degradation to occur if there are sufficient economic and social impacts.

“The TCEQ then determines whether a lowering of water quality is expected from the proposed discharge. If it is, the TCEQ then determines whether the lowering of water quality is necessary for important economic or social development and whether reasonable alternatives to the lowering of water quality are unavailable,” according to pg. 67 of the Procedures to Implement the Texas Surface Water Quality Standards.

The document does not define what the TCEQ considers “necessary for important economic and social development.”

Herrington also explained the TCEQ does not consider the data the City of Austin has collected on the impact of effluent on Hill Country creeks when issuing wastewater discharge permits. He stated the TCEQ does not consider the data the city collects.

The TCEQ confirmed the City of Austin provides data on water quality, and it is “available for the evaluation,” but they did not state whether they consult it when determining whether to issue a wastewater discharge permit.

Alternatives to wastewater discharge permits

There are several approaches to addressing the issues of these algae blooms. This can be done through legislative means, individual action, and alternatives for disposing of wastewater.

House Bill 4146 attempted to address the issue of nitrogen and phosphorus levels in effluent discharge, but it was not successful. The bill would have placed limits on the levels of nitrogen and phosphorus allowed in effluent when it was discharged into “certain stream segments.” The Texas House passed the bill, but the Senate did not.

Kelly Davis, the staff attorney for the Save our Springs Alliance, is encouraged despite the bill’s failure to pass.

“It’s important to note that some version of a bill like HB 4146 has been introduced and gone through some amount of process in the Texas Legislature since the 2000 session. This is the furthest that any such bill actually got,” Davis explained.

Davis also asserted that community-based action is effective. In April, communities in the Hill Country came together to discourage a Houston businessman from receiving a wastewater discharge permit for Longbranch creek. Community members protested the permit at a TCEQ hearing, and the businessman decided to withdraw his permit application after the hearing.

“It’s important to celebrate the small victories, stay informed, and keep putting pressure on our elected representatives and the agencies that are meant to act in the public interest to ensure that they are complying with the existing law,” Davis said.

There are also alternatives to wastewater discharge permits companies and individuals can use, such as land application permits and beneficial reuse.

A sign indicating recycled water is used for landscaping in Lakeway (Courtesy Save Barton Creek Association)
A sign indicating recycled water is used for landscaping in Lakeway (Courtesy Save Barton Creek Association)

Zabcik explained land application permits allow wastewater to be treated and then used for irrigation. Beneficial reuse allows wastewater to be treated and then recycled back into our system as non-potable water that can be used, for example, to flush toilets.  

The TCEQ explained the land application permit process is similar to the wastewater discharge permit process, but a land application permit does require land to be set aside for wastewater disposal either by subsurface drip or surface irrigation and it may have more costs associated with it.

Davis also cited an example where beneficial reuse is taken a step further.

“The city of El Paso has a direct, potable reuse wastewater system where the wastewater is treated so highly that it goes back into the public water supply system. They’ve been doing that in water-scarce places like Israel for decades,” Davis said.

Land application permits and beneficial reuse means this isn’t an either-or situation according to Barney Austin, the President and CEO of Aqua Strategies, a company that helped the City of Blanco design its wastewater disposal system.

Adding to this, Austin asserted wastewater and city growth can act in a symbiotic relationship.  

“There is a need, I think, for communities to consider wastewater at the same time they’re considering their water supply needs,” Austin said.

This is a complex issue with the need to strike a balance between allowing development and protecting the Hill Country’s creeks, but Herrington sums up why this issue needs to be addressed immediately: “There are too many people living in too much of an environmentally sensitive area to not be more proactive.”

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