The 2007 Zaca Fire burned much of the upper Santa Ynez watershed , causing huge amounts of ash-laden silt to flow into Gibraltar Reservoir . Organic material in the ash reacted with chlorine disinfectant in Santa Barbara 's water supply to form carcinogenic compounds . Cleaning up the water cost the city nearly $ 3 million . Other more recent fires have also impacted the Gibraltar watershed , such as the 2016 Rey Fire and the 2017 Thomas Fire
Zaca Fire
Zaca Fire
Gibraltar Dam