TriValley Floodplain Mapping Update Prepared by Garrett Higerd
Tri-Valley Floodplain Mapping Update Prepared by: Garrett Higerd, P. E. Mono County Department of Public Works For: The Board of Supervisors May 18, 2010
Historically, flooding in the Tri-Valley has affected roads, residences, and agriculture. A notable example was the flood of 1989.
Flood Insurance Rate Maps have not adequately shown flood risk in order to protect life and property.
Project History � 1974 – Mono County joins the National Flood Insurance Program. � 1985 – FEMA issues the first Flood Insurance Rate Map (FIRM) panels for Mono County. �Summer, 2008 – Mono LTC funded Li. DAR land surface mapping for use as the basis of future floodplain mapping studies. �August, 2009 - Mono County entered into a Cooperating Technical Partnership (CTP) agreement with FEMA.
Extent of Li. DAR Mapping
Equipment Airplane with Li. DAR equipment mounted on board. GPS base station set up on major monuments to establish control.
Where we were…
Where we are going…
Recent FEMA Mapping Progress �Winter, 2009/10 - FEMA selected Baker. AECOM as mapping contractor for the Tri-Valley study and they performed additional site surveying and a draft hydrology study. �Spring, 2010 – FEMA issued revised county-wide Digital Flood Insurance Rate Maps (DFIRM).
Next Steps �Late Spring - Baker. AECOM finalizes hydrologic study. �Summer – Baker. AECOM prepares hydraulic study. �Late 2010 – Baker. AECOM produces preliminary DFIRM. �Winter/Spring 2011 – Preliminary DFIRM roll-out and community outreach. �Summer 2011 – New DFIRM is finalized and adopted.
How will this affect residents? �The floodplain maps will change! �Flood Insurance – Prior to map adoption, homeowners will be able to purchase insurance at the rate available under the old maps. These low insurance rates can also be transferred to new owners as long as continuous coverage is maintained. �Floodplain Construction Standards – New construction and remodels within the special flood hazard area (SFHA) will have to comply with the County floodplain regulations.
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