Calaveras Dam Replacement Milpitas, CA

Construction noise monitoring Environmental impact noise testing

The San Francisco Public Utilities Commission (SFPUC) contracted URS Corporation to conduct environmental analysis work on the Calaveras Replacement Dam Project. Dam construction required excavation of earth from one side of the reservoir, near a rural residential community. Per the California Environmental Quality Act (CEQA), URS was required to estimate the noise impact from project construction at nearby residences.

To test construction noise impact, URS rented standard construction equipment to operate at the site. The equipment included loaders, backhoes and a large truck. This equipment was used to simulate noise impact due to construction activities at the construction site while noise data were gathered at the closest residential properties.

SFPUC identified three residential properties near the project construction site. We measured A-weighted noise levels every minute for a 24-hour period.  During a subset of this time, construction activities were being simulated.

The simulation was successful in addressing daytime noise impact.  Even though the data were contaminated by background (daytime) noise levels, we could identify a change in noise floor due to construction. This allowed confident scaling of noise levels to account for future additional site equipment. The levels could be compared to the CEQA significance threshold for evaluation.