About Bio-West Comal River Aquatic Restoration Project

The Edwards Aquifer in south-central Texas is an important water resource that also provides critical habitat for threatened and endangered species in the San Marcos and Comal spring and river systems. The unique habitat afforded by these spring-fed rivers has led to the evolution of species found in no other locations on Earth. Because of the potential for variations in spring flow due to both human and natural causes, the Edwards Aquifer Authority (EAA) and stakeholders have developed a Habitat Conservation Plan (HCP) to protect these unique species. The HCP seeks to effectively manage the river-aquifer system to ensure the viability of the endangered species in the face of future water quantity concerns, such as drought and increased demand from population growth, as well as water quality threats to the system.

The EAHCP partnered with environmental consulting firm BIO-WEST, Inc. to track biota and habitat conditions of the river-aquifer ecosystem, with sampling efforts specifically targeting species such as the Fountain Darter (Etheostoma fonticola), Texas wild-rice (Zizania texana), Comal Springs riffle beetle (Heterelmis comalensis) and the San Marcos salamander (Eurycea nana). Additional community level monitoring data was also collected on aquatic vegetation, fish, and benthic macroinvertebrates. The results provide valuable data to be able to further assess temporospatial shifts among aquatic floral and faunal communities of the upper San Marcos system.

Project Description & History

Under the Edwards Aquifer Habitat Conservation Plan administered by the Edwards Aquifer Authority, the City of New Braunfels, and BIO-WEST Inc., the purpose of the Comal River Aquatic Habitat Restoration Project is to improve habitat along the upper 2.5 km of the Comal River, including Landa Lake.

The project consists of removing non-native aquatic plants that have taken over parts of the Comal River and re-establishing native aquatic plants that were known to exist before invasion. Native aquatic plants have benefits to water quality, including nutrient uptake, and act as water filters that improve water quality and stabilize the river system. To undertake aquatic restoration, the group has developed a protocol to effectively remove the aquatic invasive plants using zero chemical herbicides that will cause very little disturbance to the environment. On top of this, a protocol was developed to grow sufficient quantities of native aquatic plants to provide restoration.

The primary goal of this action is to improve aquatic habitat for the endangered Fountain Darter (Etheostoma fonticola) as well as other endangered native aquatic species. Improved habitat leads to improved population numbers and survival through environmental hardships such as drought, flooding, and habitat disturbance.

Native aquatic plants, such as Ludwigia repens, are propagated at a field nursery using Mobile Underwater Plant Propagation Trays. When the plants are mature they are harvested and transported to the final planting location. Native plants are planted by hand using snorkel or SCUBA equipment. Coconut matting is used to hold the plants in place until they root and establish.

Below is an aerial view of restored Ludwigia repens (red color) in Landa Lake. This area was once occupied by the non-native aquatic plant Hygrophila polysperma.

Community Impact

The Comal River Aquatic Habitat Restoration Project is projected to impact 35,000-75,000 people, from employees to local residents and tourists visiting the area. Ecosystem services, such as erosion control and and clean water, will help promote recreational activities and tourism in and around Comal and Hays County, and provides viable habitat for endangered species that are only found in this small part of the world. A healthy and stable population of aquatic flora and fauna leads to a healthy and stable ecosystem, which benefits the surrounding communities and people traveling from near and far to witness the beauty that is the Comal River and its springs.