An Update to Our Community About New Development At Seiders Springs
May 15, 2023 | By Shoal Creek Conservancy
Many Shoal Creek Trail users know and love Seiders Springs, located on the east bank of Shoal Creek between 34th and 38th Streets. We are writing to share an update on the future of Seiders Springs. We are concerned that the Springs may be impacted by new development at the neighboring Ascension Seton Medical Center site.
About Seiders Springs
Seiders Springs is a set of historic and somewhat mysterious artesian springs that are known as a tucked-away landmark on the Shoal Creek Trail. The springs flow directly from a limestone cliff face and flow over land into the creek, creating a unique wetland habitat. The springs include a set of seeps as well as a northern and southern spring. The seeps are a slow, steady flow of water emerging continuously from contact of two geologic layers that are over 90 million years old. Water in the northernmost spring is almost always running, in contrast to the southern spring (shown in the photo to the left), which flows intermittently.
The springflow supports a wetland on the banks of Shoal Creek creating a habitat that is regularly visited by native wildlife even during summer drought, when the rest of Shoal Creek is running low or dry.
People have been coming to these fresh, cool waters for thousands of years. In the 1870s, the Springs even became the site of a well known local bathhouse. For a brief history of Seiders Springs listen to Stop 1 of the Shoal Creek Audio Walking Tour. We are lucky that Seiders Springs are now located in parkland and are accessible to the public along the Shoal Creek greenbelt. As the area around Seiders Springs continues to redevelop and adds new residents and businesses, keeping the Springs protected and flowing is more important than ever.
Ascension Seton Medical Center Development
The Ascension Seton healthcare group represents Seiders Springs’ closest neighbors. They are expanding their important medical facilities on the eastern side of Shoal Creek, in the area bounded by Lamar Blvd to the east, Shoal Creek to the west, 34th Street to the south, and 38th Street to the north. Planned additions include a new Women’s Health Tower and an expansion of the hospital’s cardiovascular wing.
The sites of both planned expansions are currently being used for parking. Seton is planning to relocate this parking to the western edge of their property which is adjacent to Shoal Creek. Specifically, they are planning two new parking facilities at 38th and at 34th Streets which will each reach three stories underground. In addition to the underground parking, the south garage at 34th will have several floors aboveground, and the north garage at 38th will have a surface parking lot at street level.
With these major excavations so close to the Springs, Shoal Creek Conservancy is concerned about possible impacts to the spring flow.
In fact, the City’s master comment report that was issued in approval of the site plan includes a warning to this effect by a City hydrogeologist:
“FYI: Current Code and Criteria limit regulation of disturbance/construction activities to within 150’ of the surface expression of seep/spring. While the proposed subsurface garage/s limits of construction are outside of the standard 150’ setback, serious concerns about the project and potential impacts to critical environmental features (CEF) exist.
“As designed, subsurface garage will intercept groundwater and likely negatively impact historic Seider Springs, associated wetland CEF, and baseflow of Shoal Creek… During subsurface boring activities in March 2022, groundwater was encountered in separate, but adjacent borings at 11’ to 13’ below ground surface… Subsurface geotechnical borings for Phase II (38th Street Garage) are pending completion.
“While the design meets the requirements set forth in LDC 25-8-281 and is therefore approved, alternative design and development strategies should be considered to reduce or even eliminate the impacts to the groundwater located on-site to preserve the water quantity/quality of the spring and ensure the ecological sustainability of the area.”
Is this development following the rules?
Yes. Ascension Seton completed an environmental resource inventory that identified the springs and wetland as critical environmental features. The City’s land development code requires a 150’ setback around all critical environmental features. Ascension Seton’s plans conform with this requirement: there is no construction planned within 150’ of the spring outfalls or wetlands. Although the plans fulfill the letter of the law, we are concerned that such significant disturbances to the geology in this area could interrupt flow paths that convey water to the springs. Because the springs emerge from the rimrock so close to the surface of the ground, it is likely that excavations will hit groundwater at a relatively shallow point.
What are the solutions?
At this point, any redesign of the garages will have to be voluntarily pursued by Ascension Seton. Because the project complies with code, the City of Austin has no regulatory mechanism to require that Seton design the parking garages in a particular way to protect the springs. In fact, local regulations on building height make it difficult, if not impossible, to construct a fully aboveground parking garage with Ascension Seton’s desired capacity.
If all parking levels were built aboveground, the foundation of the garage would include a belowground pier and beam structure that disturbs a fraction of geology compared to the planned full scale excavation of approximately a city block.
What happens next?
SCC’s goal has been to find a path forward that allows Seton to build these important facilities and also protect this beloved and sensitive environmental feature. We are thankful that Seton has offered their commitment to work with SCC throughout the project to assure that no harm will be done to the Creek or Springs.
Excavation at the site of the south garage began the first week of May 2023, and is expected to continue for the next 5 weeks. In the event that construction crews encounter groundwater, they are required to contact the City of Austin to create a plan for rerouting the groundwater away from the site.
What can you do to help?
We need volunteers to serve as extra eyes and ears on the ground around the Springs. If you visit the area regularly, we would love your help in monitoring spring flow and other factors. Sign up below for more information.
We also appreciate our cleanup and riparian restoration workday volunteers. Over the past year and a half, SCC has led small volunteer groups in restoring native creekside habitat in the area around Seiders Springs, including the wetland area. And efforts have already begun to pay off. During the August 2022 flood, the Creek jumped its banks and floodwaters inundated our restoration area. The deep rooted sedges we planted kept the streambank intact despite the force of the floodwaters.