It wasn’t your typical walk in the park as Edwards Aquifer Habitat Conservation Plan (EAHCP) leadership team guided about 55 people through a series of improvements made in the Comal River’s historic Old Channel. The attentive group included members from all three EAHCP committees, representatives from local, regional, state and federal environmental agencies and some students. Over the course of the tour, the tour group would get a first-hand look at the flow-split management retrofits, submerged aquatic vegetation plantings, riparian restoration, bank stabilization and water quality sampling operations which have helped improve the habitat for the endangered fountain darters over the last few years.
At the first stop, Mark Enders from the City of New Braunfels explained how the new flow-split system is helping direct Comal Springs water into the river’s Old Channel where fountain darter habitat is found. Onlookers could see the recently installed valve and gauge system that will play a central role in diverting water into the Old Channel during times of drought.
“The flow-split system project started in 2014 and has now been operational for more than a year,” Enders explained. “Essentially, that system gives us a means to funnel as much water into the Old Channel as needs to be there, whereas in the past, fountain darters and their habitat in Old Channel would not have enough flows during drought conditions. We have nearly 20 years of biological data some of which predates the flow-split system and some that we’ve recently gathered. In studying that data, we’ve learned that maintaining about 65 cubic feet per second (CFS) of water flowing into the Old Channel is optimum for the species. The rest of the water flows into the New Channel. It’s pretty clear that the flow-split system will be an invaluable tool during those dry periods and low-flow conditions in the river."
In addition to controlling flows into the Old Channel, the EAHCP team determined a need to stop the spread of non-native vegetation and start the process of replanting native plants that are more conducive to improving habitat for the endangered species. Ed Oborny, Senior Aquatic Biologist for BIO-WEST, said that prior to the EAHCP, 25 percent of Landa Lake was inundated with non-native vegetation. In some areas along the Comal River, hygrophila covered the stream bank to bank.
“As we began the plant removals, we measured about 100 square meters of the non-native hygrophila plants and only about 10 square meters of the native ludwigia,” Oborny noted. “Today all of the non-natives are gone from Landa Lake and we’re learning every day about how best to plant and manage the native vegetation. Additionally, we are continually mapping the vegetation in the system which will help us improve our vegetation management and species growth sampling over time. The bottom line is that the health of this ecosystem is driven by vegetation, and we’ve also verified that native vegetation provides a better habitat for the fountain darters.”
Another major factor in keeping habitats viable is the water quality in the river. Dr. Chad Furl, Chief Science Officer for the EAHCP, pointed out the five, real-time water quality monitoring stations the Edwards Aquifer Authority maintains in the system.
“Each station is strategically placed in the system to provide data we need to determine the overall health of the system and effects of our overall programs,” Furl said. “Our team comes out weekly to ensure each station is operating efficiently so we are gathering accurate data. The data that is collected goes into a very large database at the EAA so we can study current conditions and trends in the system. We know if the dissolved oxygen in the water is good, where and when water turbidity occurs and the exact temperature of water in the river. All of those parameters impact the quality of the ecosystem and that’s why we focus so heavily in acquiring that information.”
EAHCP Program Manager Nathan Pence concluded by explaining the impacts of the work now underway and expected to continue in years ahead.
“When we got started, we had a bunch of goals but there were no operating procedures to go along with those goals,” Pence stated. “The refugia facilities, river bank stabilization projects, water quality and bio-monitoring systems along with other components of the EAHCP have only improved with each new step we take. There is tremendous collaboration among EAHCP partners and even community volunteers that makes this work possible. And while we have very specific permit requirements to meet, we all recognize this environmental work will help improve benefits these natural resources will provide to communities in the Edwards Aquifer Region for decades to come.”