Impacts of Cole Creek Flooding
- Poor Water Quality in Clear Lake — Floodwater picks up nutrients from septic systems, animal manure, and fertilizers, then drains to Clear Lake, fueling toxic algal blooms and spreading debris and trash downstream. The 2026 Clear Lake Rehabilitation Final Report by UC Davis found that Cole Creek has the second-highest ratio of bioavailable phosphorus (37%) of all sampled tributaries—making our creek disproportionately potent in feeding algal growth. The report also found that 17% of Cole Creek's sediment phosphorus is in the Iron-Aluminum form most likely to release into the water when oxygen levels drop. Stabilizing the channel is therefore critical not only for flood control but for protecting Clear Lake's water quality. Flooded vehicles also leak gasoline, oil, and antifreeze, sending additional toxic chemicals toward the lake.
- Threat to the Clear Lake Hitch — Prolonged inundation traps endangered hitch in shallow pools where they suffer from low oxygen, high temperatures, and predation, leading to mass die-offs each spring. During the 2024 spawning season alone, the Big Valley Band of Pomo Indians rescued 14,930 hitch along Cole Creek—yet countless more perished before help could arrive.
- Mosquito Breeding Grounds — Stagnant flood-waters create ideal habitats for mosquitoes, unleashing swarms that heighten the risk of West Nile virus and other vector-borne diseases for thousands across the region.
- Structural Damage — Fences, sheds, barns, and access roads sit under water for months. Wooden posts rot, metal corrodes, and repeated repairs impose heavy costs on landowners.
- Lost Agricultural Productivity — Fields remain water-logged well into the growing season, preventing planting, stressing perennial crops, and reducing pasture availability for livestock.
- Limited Emergency Access — Road closures isolate the neighborhood; flooded routes keep fire engines, ambulances, and other critical services from reaching homes for hours or even days, putting lives and property at greater risk.
- Unsafe Drinking Water — Some residents report discolored or foul-smelling tap water coming from their wells during and after the flood season, raising fears of bacterial contamination and long-term health risks.
