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Floods
Introduction
Siletz River Flood (1999)
DLCD Natural Hazards program serves as the state´s coordinating agency for the National Flood Insurance Program (NFIP) through an agreement with the Federal Emergency Management Agency (FEMA). Oregon has 258 cities and counties that are subject to flooding, and all participate in the NFIP thereby making flood insurance available to their residents and businesses.
 
The NFIP has three basic components: - flood hazard mapping, floodplain insurance, and floodplain regulations. Does the combination of mapping, regulations, and insurance work to reduce flood damages? Yes, according to FEMA, flood insurance provides an alternative to publicly funded disaster assistance that reduces the ever escalating costs of repairing damage to buildings and their contents caused by floods. FEMA further reports that flood damages are reduced by nearly $1 billion a year nationally through communities implementing sound floodplain management requirements and property owners purchasing flood insurance. Newer buildings constructed in compliance with floodplain regulations suffer approximately 80 percent less damage annually than those not built to current standards.
 
SOURCES:
 
Another NFIP analysis showed that only 2% of NFIP claims examined were for new buildings constructed after communities received their flood maps and adopted their flood damage prevention ordinances, i.e., 98% of the losses were to buildings that pre-dated community based floodplain management. Other studies have shown that the majority of new residential and other development is now directed away from areas subject to flood hazard areas thereby protecting life and property.
 
For more information about floodplain mapping, floodplain insurance, and floodplain regulations, continue searching this section of the Department’s website and/or visit the FEMA website at (http://fema.gov/business/nfip)

The Value of Floodplains
The floodplain is the area susceptible to inundation by flood waters. Under the NFIP, the "100-year" floodplain is commonly referred to and includes the area that would be inundated by a flood having a 1% chance of occurring in any given year. A "100-year" flood can occur during any given year if conditions are right.
 
Floodplains perform a variety of functions and in the process prove valuable to both humans and fish and wildlife species. Important functions of your community floodplain might include all of the following: flood water storage, water quality maintenance, fish and wildlife habitat, and recreation/open space. What happens in your community’s floodplain can have impacts to human uses and natural resources within your community as well as in areas located downstream.
 
In terms of the natural environment, floodplains include important habitat areas such as river channels, the water's edge, riparian buffers, wetlands, and upland areas adjoining flood-prone areas. The variety of habitat types, the presence of water, and other factors generally result in a rich diversity of plant and animal species within floodplains. (This of course may no longer be the case in highly developed floodplains.) And it is the hydrological and geological characteristics of the floodplain that largely shape the type and location of various habitat types. Many of the plant and animal species found in floodplain habitats are adapted to specific soil, nutrient, and water conditions. Additionally, vegetation that grows in the floodplain helps determine how water flows across the land and can play a major role in controlling erosion and sediment deposition.
 
Did you know that flooding is extremely important to the maintenance and biological richness of floodplain ecosystems? For more information about the natural values of floodplains, check out the publication "Protecting Floodplain Resources: A Guidebook For Communities"  by FEMA’s Federal Interagency Floodplain Management Task Force, 2nd Edition - June 1996.

Floodplain Management
Floodplain management aims to reduce flood losses to life and property while simultaneously protecting the natural resources and functions of floodplains. Development within floodplains is generally not prohibited, but floodplain management involves regulatory, construction, and public education measures designed to avoid and minimize potential risk to development from flood hazards. Floodplain management also entails implementation of mitigation measures or, in other words, specific actions that can be taken to prevent future damages and threats to human life and public health.
 
Oregonians will continue to make use of floodplains for a variety of purposes. Floodplain management involves recognition that our use of floodplains can negatively impact floodplain functions and that communities will be faced with making choices about land uses in the floodplain. Loss of important floodplain functions, for example flood storage capacity or habitat diversity, is a concern for DLCD and should be a concern for community leaders as well as affected citizens. In some cases, community choices may be limited by past development patterns and other land-use decisions. But hopefully, current decision-making under local floodplain management programs will include adequate consideration and understanding of the potential consequences of altering floodplain functions.
 
DLCD’s site provides floodplain management information specifically designed for property owners, developers, and local governments but should also serve the general public. The topics addressed here have been selected based on the NFIP questions that the department is most frequently asked. If your question is not answered here, then please contact the department so that we can assist you.
 
http://www.fema.gov/plan/prevent/floodplain/index.shtm
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