NewsDrop-March-April-2026

EDWARDS AQUIFER HABITAT CONSERVATION PLAN (EAHCP)

By: Kristina Tolman Senior HCP Coordinator

2025 EAHCP OVERVIEW

The EAHCP is a regional program that protects aquatic habitat for endangered species in the Comal and San Marcos springs systems while ensuring the sustainable, long-term use of the Edwards Aquifer for permitted users. visit: www.eahcprenewal.org

2025 was the 13th year of EAHCP implementation and the third consecutive year of extreme drought conditions. Drought conditions reduced springflow in the Comal Springs system to a low of 48 cubic feet per second (cfs) in May, among the lowest observed flow since the 1950’s, also known as the region’s Drought of Record. The decreased springflow caused major Spring Runs 1, 2, and 3 to temporarily go dry in the Comal Springs system and significantly reduced available wetted habitat. THE EXTREME DROUGHT CONDITIONS IN MAY TRIGGERED A LOW-FLOW MONITORING EVENT AND THE USFWS PERFORMED THE FIRST EVER “SALVAGE” EVENT OF THE ENDANGERED FOUNTAIN DARTER FISH IN THE COMAL SYSTEM. In late May, U.S. Fish and Wildlife Service (USFWS) Refugia staff captured hundreds of fountain darters to protect the genetic diversity of the wild population in case springflow decreased further or stopped flowing.

The salvaged fountain darters were temporarily housed at the San Marcos Aquatic Resources Center until springflow conditions improved and the wild population was reintroduced back into the system in October. The Comal Springs system not only suffered extreme low-flow conditions in May, but also extreme flooding on June 12, 2025, when stormwater increased the flow above 6,000 cfs and then again above 1,000 cfs on July 5th and 7th. The extreme flooding dislodged a large portion of the bryophytes, or non-rooted aquatic vegetation preferred by the fountain darters, in Landa Lake and the Comal Springs system. Therefore, fountain darter habitat was not only adversely impacted and reduced by the extreme drought conditions in May but also the flooding conditions in June and July. Comal invertebrates, including the Comal Springs riffle beetle, Comal Springs dryopid beetle, and the Peck’s cave amphipod, had some of the highest calculated annual disturbances in 2025 compared to years prior due to the reduced available habitat in the major Spring Runs (1, 2, and 3), Western Shoreline, and Spring Island. The flooding in June and July temporarily improved springflow conditions, yet flow continued to decline into fall and ended the year at well below average conditions. Routine biological monitoring occurred in spring and fall, while additional low-flow monitoring occurred in

January, May and July to assess the impacts of the drought conditions as well as the flooding impacts in June and July. Historically, Comal Springs are the largest spring system in the State of Texas and San Marcos is generally the second largest; however, San Marcos springflow surpassed Comal springflow for much of the year and stabilized around 80 cfs, still well below historic average conditions. San Marcos aquatic habitat was impacted by reduced flows and exposed habitat, yet overall, the disturbance was lower than anticipated. The occurrence of bryophytes, or preferred habitat of the fountain darter, increased in areas previously not found, improving fountain darter densities in select river reaches. San Marcos salamander long-term biological goal densities were achieved in two of the three monitoring reaches and Texas wild-rice coverage was approximately 12,586 meters 2 , above the long-term biological goal coverage. In 2025, the City of San Marcos implemented new methods of managing and reducing the impacts from aquatic recreation through enforcement of the new reusable beverage container ordinance, temporarily fencing and monitoring access points around Rio Vista Park-the busiest riverfront park during the summer, and implementing new paid parking at the City Park

Comal Habitat Evaluation: Water flowing over the weir dam in the New Channel at 70 cfs (March 19th).

USFWS staff reintroducing fountain darters back into the Comal Springs system in October 2025.

riverfront park. Texas State University installed new educational signage in Sewell Park and above Sewell Park, and installed new permanent fencing above Sewell Park, near Kerby Lane. The newly fenced area still allows public access but provides Texas State University with the option to close or restrict public access to this sensitive area, if needed, thus protecting critical habitat for the fountain darter, Texas wild-rice, and the San Marcos salamander. The Permit Renewal team, through coordination and input from the five Permittees, EAHCP Staff, EAHCP Committees, and USFWS staff, completed

three memoranda summarizing recommended changes related to the Conservation Measures, Take Assessment Framework, and Monitoring and Adaptive Management Framework. Recommended changes to the Conservation Measures expanded upon changes proposed by the Conservation Measures Subcommittee Work Group in 2024 and include changes to the Springflow Protection measures framework, combining and restructuring of the San Marcos Habitat Protection measures and revisions to the Measures that Contribute to Recovery. Take Assessment Framework changes include shifting from a species-approach (estimated

number of individuals) to a comprehensive habitat based approach. All three memoranda are available on the Permit Renewal website. The government shutdown in the fall of 2025 temporarily suspended Permit Renewal coordination activities with USFWS causing some scheduling delays for finalizing certain recommended changes and release of the new draft HCP. 2026 Permit Renewal activities will include finalizing a Cost and Funding memorandum as well as refining the chapter content of the new draft HCP.

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