For many years, the San Antonio River Authority (River Authority) has valued partnering with the National Park Service’s (NPS) San Antonio Missions National Historical Park (NHP) staff toward the agency’s vision of inspiring actions for safe, clean, and enjoyable creeks and rivers in the San Antonio River Basin. Both the NPS and the River Authority are founding members of the World Heritage Management Group (WHMG) for the San Antonio Missions: an oversight body whose purpose is to continue the high level of coordination and partnering to ensure that these cultural resources are protected in perpetuity. All five Spanish colonial missions in San Antonio, Texas, including Mission Valero (the Alamo) are a single United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Site, the San Antonio Missions World Heritage Site. Together, they are the most complete and intact group of Spanish Colonial mission complexes in the world. In 2023, the WHMG, led by the NPS, completed its first “periodic reporting” to UNESCO since the site’s inscription in 2015. Today’s blog will share highlights from the past year of partnership between the River Authority and the NPS!
Native Arrowhead Plant Transplanted from Historic Acequia into San Antonio River
On August 16, 2023, the Texas Conservation Corps (TXCC) and the River Authority worked together at San Antonio Missions NHP to relocate Sagittaria plants from the Mission San Juan acequia to the San Antonio River for habitat restoration. Sagittaria, or the Arrowhead plant, is a native plant species and is beneficial in natural river and stream ecosystems. The TXCC members worked alongside employees from the River Authority’s Watershed and Park Operations team to remove the overgrowth of plants in the acequia, which are Spanish colonial irrigation ditches that to this day function as a water utility system. The youth corps is funded by the NPS and the Land Restoration Fund for acequia preservation and is part of the Great American Outdoors Act (GAOA) Maintenance Action Teams (MAT). This crew began working with San Antonio Missions NHP staff on the acequia preservation project on July 24th, 2023 and their work was funded for a 10-month period. Three full utility carts of plants were removed and transplanted with this effort.
Water Quality Sampling and Environmental Surveys
The River Authority has worked with NPS for more than 15 years to collect and analyze water quality samples, conduct fish, mussel and habitat surveys and even look for reptiles and amphibians on various NPS properties in the San Antonio River Watershed. Water quality samples are collected from Piedras Creek near the Espada Aqueduct by Stinson Airport, Acequia de Espada, San Juan Acequia and a historical remnant channel of the San Antonio River. These quarterly water quality samples help NPS and River Authority staff monitor the health of these systems and better understand what types of aquatic communities they can support.
The San Antonio River remnant channel near Mission San Juan is much narrower and more densely vegetated than the Mission Reach.
Fish and habitat surveys provide additional information on ecological health. Since 2015, 14 fish species have been observed from these NPS sites, including Largemouth Bass, Bluegill, Green Sunfish, Channel Catfish. Guadalupe Bass, the state fish of Texas, was even reintroduced into the remnant channel in 2016!
Juvenile Guadalupe Bass being released into the San Antonio River remnant channel in 2016. The state fish of Texas has thrived since being reintroduced to the river!
Recently, the River Authority celebrated the first ever freshwater mussel reintroduction in the state of Texas. How did we know it was a reintroduction? By finding live mussels and mussel shells in the remnant channel. While no juvenile mussels were found in the remnant channel, some adults were found, meaning the water quality and quantity were enough to support these animals throughout the construction of the Mission Reach. Scientific collaboration is key to maintaining the health of the San Antonio River, and the partnership between NPS and the River Authority continues to benefit environmental health!
Pimpleback (left) and Paper Pondshell (right) mussels were found in the San Juan remnant channel during mussel surveys in 2015. This relic population helped spark the idea by reintroducing mussels into the Mission reach!
Education and Engagement
The River Authority’s Education team collaborated with San Antonio Missions National Historical Park staff to share information and collaborate on a series of 10 field trips during the 2023-2024 school year. River Authority staff headed to Mission San Jose and Mission San Juan to provide a hands-on demonstration of how the San Antonio River Watershed works. Students learned how pollution affects their local creeks and rivers, and how to continue taking care of our precious freshwater resources. In turn, NPS staff engaged students on River Authority field trips at Confluence Park in hands-on activities and discussions of the historical and cultural importance of the San Antonio River, as well as advice on how to become a park ranger! Are you interested in taking a field trip with NPS or the River Authority? Learn more about education programs at San Antonio Mission NHP and programs with the San Antonio River Authority.
Park Ranger Anna Martinez-Amos leads River Authority Public Affairs and San Antonio River Foundation staff on a tour of Mission San Juan.
Students visiting Mission San Jose learn about the San Antonio River with the Watershed Model as they stand next to the Gristmill.
River Warrior Tour at Rancho de las Cabras
In April 2024, the River Authority and the National Park Service joined education expertise to provide a tour for River Warrior volunteers at the historical Rancho de las Cabras. The venue, with its preserved prairie land, also provided an ideal environment for practicing iNaturalist observations prior to the 2024 City Nature Challenge, in which the San Antonio Metro Area won 1st Place in Texas!
Get Involved
Any history buffs out there? Join the River Authority, along with the NPS and other partners at Historic Plaza Days this summer!
Celebrate the cultures that built our city with live music, tasty bites from local food trucks, and engaging activities from community organizations. Whether you’re a local or visiting, there’s something for everyone! Bring your family and friends to have some fun at Main Plaza. Let’s celebrate San Antonio’s heritage together!
Finally, we encourage you to visit the San Antonio Missions National Historical Park as well as the adjacent Mission Reach of the San Antonio River Walk.
