The Riverside Ponds and Headworks Mitigation Project is a critical infrastructure effort designed to protect the City of Calistoga’s Wastewater Treatment Plant (WWTP) from the increasing threat of flooding and erosion caused by channel incision along the Napa River and Simmons Creek. To enhance the plant’s long-term resilience, the project includes stabilizing eroding riverbanks, elevating pond berms to withstand 100-year flood events, and widening portions of Simmons Creek to reduce erosion and improve flow capacity. These improvements are essential to maintaining uninterrupted WWTP operations and ensuring compliance with regulatory standards set by the San Francisco Bay Regional Water Quality Control Board. Ghirardelli’s team is responsible for overseeing all construction activities, ensuring that work is completed to specification, on schedule, and in full alignment with environmental and regulatory requirements.