Update 8:13/2025 10:54 AM: The Rivanna Water & Sewer Authority has concluded today’s testing of the new Sugar Hollow Dam High Water Alert System. The system’s siren and strobe light energized as designed.
Update 8/11/2025 8:00 AM: RWSA plans to test the Sugar Hollow Dam High Water Alert System on Wednesday, August 13, at 10:00 AM. Residents and visitors in the vicinity may hear the siren. During the test, there is no need to seek higher ground. The test will consist of two separate 3-minute blasts. The testing process is expected to finish by 10:15 AM.
Update 7/22/2025 4:30 PM: RWSA has concluded today’s testing of the new Sugar Hollow Dam High Water Alert System. The system’s siren and strobe light energized as designed. Staff will continue work on developing a regular testing program as well as installing downstream signage. Future updates will be shared as progress is made.
Update 7/22/2025: Contractors and staff will be on-site this afternoon (7/22) testing the new system. Testing will occur between 2:00 PM and 4:00 PM. If you hear the siren, please do not panic. There’s no need for any immediate action. An update will be published once the testing process is complete.
Update 7/18/2025: RWSA anticipates testing the new siren within the next week. Testing may occur as soon as Monday afternoon (July 21, 2025) but may extend later in the week. Communication will be sent immediately to local residents (and to those who have signed up for our e-newsletter) before each test. If you are in the vicinity and hear the siren, please do not panic. No immediate action is required. Upon a successful test, RWSA will install safety signage informing residents and visitors about the siren and what to do in the event the alarm sounds. These signs will be installed downstream of the Sugar Hollow Dam. A regular testing program will be implemented to ensure the alarm system operates properly. Additional details regarding the testing program will be forthcoming.
Background
Dam safety alert systems are important to provide early warnings in the unlikely event of potential dam failures or dangerous water releases. These systems monitor operating metrics to detect abnormalities, allowing for the appropriate activation of alarms. Effective alert systems help minimize the impact of floods, reduce economic losses, and ensure community resilience, making them a vital component of modern dam safety management.
In 2024, the Sugar Hollow Dam experienced a mechanical issue with its affixed rubber bladder that allowed excess water to flow downstream. The event prompted RWSA to reassess the dam’s redundancies related to the bladder and to explore potential alert systems. Improvements to the rubber bladder, its pneumatic piping systems, and control systems were completed in early July 2025.
New Alert System
RWSA has shifted its focus to procuring a new alarm system that will alert downstream residents to potential high-water events. RWSA plans to install an interim prototype siren system in the summer of 2025.
This system includes a high-mount audible siren located adjacent to the dam and future information signage alerting individuals about the nearby dam. RWSA will field-evaluate the features of the siren system. If the test pilot goes well, RWSA plans to expand the alert system to its other dams.
Individuals interested in learning more about the project and who want to receive regular updates can sign up for our e-newsletter above.
Past Communications
8/11/2025 Testing of the Sugar Hollow High Water Alert System
7/22/2025 Testing of the Sugar Hollow High Water Alert System
7/18/2025 Sugar Hollow High Water Alert System