Gate Replacement Improves Water Control and Safety Along San Antonio River Walk
The San Antonio River Authority’s (SARA) Nueva Street Gate 5 Replacement project received a Silver Award at the American Council of Engineering Companies (ACEC) Texas 2025 Engineering Excellence Awards.
Project Summary
In January 2021, a critical failure in one of the key components of the San Antonio River system caused the Nueva Street Dam East Gate to malfunction, posing a flood risk to Downtown San Antonio.
Nueva Street Dam Gate 5, which was originally installed in the mid-1980s, is part of a crucial system of water control features installed throughout San Antonio due to the city’s geography. The series of water regulation gates and channeled waterways manage the river’s flow, maintain safe water levels and isolate the tourist-heavy River Walk from the rest of the river during severe weather events.
Freese and Nichols partnered with SARA to conduct a thorough analysis of the gates to design a replacement hydraulic crest gate and bypass system to control water flow and prevent future flooding. With a major storm and fiesta celebration along the River Walk on the horizon, the project team had to act quickly and efficiently.
Innovative Approaches
To minimize wear and tear on the gates and streamline operations, the project team identified that the control system and the gates were antiquated and recommended replacing the existing gates with a hydraulically operated crest gate system.
Installed at the dam’s crest, these gates consist of a movable barrier operated by hydraulic cylinders, allowing the gate to be raised or lowered to regulate water flows and maintain navigable water levels for boats. This efficient and reliable approach effectively achieved SARA’s flood control objectives and enhanced barge operation and tourist safety and experience.
For an in-depth look at the challenge of replacing the flood gates, check out Practical Engineering’s recap video of the project.
Practical Results to Meet Unexpected Challenges
During the early phases of the East Gate replacement, an unexpected mechanical failure occurred at the West Gate, creating a challenging situation. A resolution was urgently needed because of a rainstorm approaching and a major Fiesta San Antonio parade scheduled for the River Walk.
The project team swiftly addressed the problem, recognizing the sensitivity of the timeline and the need for a long-term solution. To expedite restoration of gate operations, the team carefully sequenced the project, ensuring that reconfiguration of the existing pump station — located adjacent to the gate — could serve as a gate-and-chute flow bypass system.
Shane Osborne, with Freese and Nichols’ Water Resource Design team, said this system lets up to 75 cubic feet of water flow without a need to adjust the gate positioning. This allows for a fine-tuned control of the river level and reduces the need for frequent gate adjustments due to upstream barge traffic and lock-and-dam operations.
Protecting the Community and Environment
The project team demonstrated a strong commitment to the community by minimizing both environmental and economic impacts on the city. Throughout the project, SARA implemented measures to support the ongoing use of the River Walk while safeguarding city traffic, water quality and aquatic life — reinforcing the team’s mission to provide outstanding service to residents and tourists alike.
To protect water quality and aquatic life, Freese and Nichols and SARA collaborated to establish best practices for dewatering and water management during construction. By preventing pollution-related impacts and using sustainable materials, they kept the river’s ecosystem intact.
SARA also took meticulous care in developing comprehensive traffic management plans to reduce disruptions. The team met with the contractor biweekly to review construction activities and proactively informed the public of any work affecting traffic, such as crane operations for gate installation.
Spanning 19 months (April 2023 – November 2024), the project successfully protected the River Walk from floods and equipment failures while preserving public access to this vital tourist destination. By prioritizing the health and safety of both visitors and the local community, the team helped maintain the River Walk’s role as a major economic driver for San Antonio.
This recognition highlights Freese and Nichols’ commitment to providing innovative results by adapting existing technology and creating practical results via close collaboration with the client to safeguard an economically vital historic area while preventing disruptions to the vulnerable San Antonio River ecosystem. Thanks to contractor Guido Construction and subconsultant Floodace for their contributions to the success of this project.
