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Know Your Flood Hazard
Visalia Flood Hazards
The City of Visalia is located in the southeastern region of the San Joaquin Valley in Tulare County. The City lies on the lower portion of a large alluvial fan formed by the Kaweah River and its distributary channels at the foot of the Sierra Nevada Mountains. Flow regulation on the Kaweah River upstream and infrastructure on the alluvial fan render the fan inactive. Although the Terminus Dam was constructed on the Kaweah River upstream of Visalia in 1962, the limited capacity of the dam results in a loss of control of downstream discharges during large events (Corps, 2005). The northern edge of Visalia is bounded by the St. Johns River, which bifurcates from the Kaweah River about 12 miles upstream of the City at McKay’s Point. Numerous canals and waterways convey flow through Visalia and supply irrigation water to adjacent farmlands. Based on the nhc (2007) FIS study, the primary causes of flooding in the City are from the St. John’s River and from overland flow approaching from the eastern edge of town. (Visalia Flood Management Conceptual Alternatives for Flood Risk Reduction 2010).
Hydraulic Analyses (Alluvial fan information)
Natural Beneficial Functions of Storms
A majority of rainfall is captured and used to recharge our ground water table. Rain is collected through storm drain systems that are directed to City recharge basins. It is important that we protect and maintain these drainage areas; the quality of our drinking water depends on it! Furthermore, proper drainage helps reduce the risk of flooding. It is illegal for any direct or indirect entry of any solid, liquid or gaseous matter to enter the drainage system including open channels. City of Visalia Ordinance 13.08 and 8.32. The City inspects the drainage system on a regular basis and removes blockages that are found or reported. If you live near areas where waters flow, you can help in this process by keeping the banks clear of brush and debris. Reports of any violations should be made to the Public Works Department at (559) 713-4465.
Special Flood Hazards
Terminus Dam is located approximately 20 miles northeast of Visalia. Terminus Dam and Reservoir (Lake Kaweah) are a multipurpose dam and reservoir completed by the Corps in 1962 to provide flood control, recreation, and irrigation water supply storage. The dam consists of a main earthfill dam and an earth filled auxiliary dam. The auxiliary dam extends across a saddle, south of the main dam. The top of the dam is at elevation of 750.0 ft NGVD. Total storage at the spillway crest (elevation 747.0 ft NGVD) is 263,000 ac-ft. (Terminus Dam Failure Study Lake Kaweah to Tulare Lakebed Flood Inundation Report 2006).
Depending on the type and location of Dam failure, the City of Visalia will experience significant impacts from flood inundation. Follow the link immediately below to look up Terminus Dam Failure Study Lake Kaweah to Tulare Lakebed Flood Inundation Report
Flood Maps
Follow the link immediately below to direct you to current and historic FEMA Flood Insurance Rate Maps.
Look Up Your Property Flood Zone
Follow the link immediately below to look up your property’s flood zone designation.