Then and Now: The San Antonio River
As part of our 130th anniversary, this series features historical photos that connect to the work we still do today.
Then: Creating Flood Protection in Downtown San Antonio
Freese and Nichols has been active in South Texas for nearly a century, and has a long history of flood control work on the San Antonio River. San Antonio became the firm’s —then called Hawley, Freese and Nichols— second home when it established a branch office there in 1928. A major job for the San Antonio office was to plan a storm water system and design the Great Bend Cut-Off Channel on the San Antonio River. The City of San Antonio had Hawley, Freese and Nichols design the cutoff after a flood on the river inundated the downtown area. The firm’s 1929 flood protection work made possible one of the city’s most famous features, the “Paseo Del Rio” or San Antonio River Walk.
Now: Maintaining a Beloved City Treasure
96 years later, we’re still working on the San Antonio River. Our team has regularly worked with San Antonio River Authority providing engineering services, including the Nueva Street Gate 5 Dam Replacement and Emergency Sheet Pile Repairs Mission Reach San Antonio River. We have also completed design services for gate improvements to help provide top safety and functionality ahead of San Antonio’s iconic Fiesta, a city-wide, multi-day, multi-million-attendee event that takes place each spring.
Nueva Street Gate 5 Dam Replacement
The San Antonio River flows directly through downtown San Antonio, home of the famous River Walk shopping and recreational area. The area is particularly sensitive to changes in river height and prone to flooding during high water events. Large-scale flooding threats are controlled through an underground tunnel system and a series of gates along the river that can be adjusted to limit flows through downtown and the Riverwalk area.
In early 2021, when the eastern gate of Nueva Street Gate 5 failed, it severely impacted the city’s ability to control downstream flows to the downtown and Riverwalk areas. The San Antonio River Authority (SARA) hired Freese and Nichols to inspect the gate and provide design solutions and construction oversight. During inspection, it was determined that the gate and its control system were at the end of their useful lives and needed to be replaced. After alternatives analysis and review of replacement options conceptual designs that included a variety of selection criteria and cost estimates, SARA and the City selected a new hydraulic crest gate system that allows greater reliability and control of river flows to protect the Riverwalk and downtown areas.
San Pedro Creek Emergency Sheet Pile Repair
SARA replaced a 200-foot retaining wall that was failing where high shear stress at the outer bend of San Pedro Creek caused it to detach from its original location. There were safety concerns about the embankment failing along the high-traffic Mission Reach hike and biking trail adjacent to the exposed sheet pile.
To act quickly, the project required two phases, beginning with an immediate, temporary design solution to protect the embankment and reinforce the existing sheet pile to prevent it from shifting more until the permanent repairs were completed.
The initial solution included the delicate placement of gravel-filled bags to keep the sheet pile in place, fill voids, and prevent further damage, which was made more challenging with high winds during the process, but it was successful. Moreover, the results were natural-looking and aesthetically pleasing, which was important to SARA.
