Natural and Beneficial Functions and Drainage System Maintenance
- Updated on Tuesday, October 2, 2012, 7:33 pm
Maintaining the flow capacity of rivers and streams requires cooperation and assistance to prevent flooding and bank erosion. Here are some suggestions and information for understanding how floodplains function and how the City regulates the floodplain to protect property and lives while affording city residents the ability to obtain flood insurance:
Recognize the natural and beneficial functions of floodplains
Floodplain lands and adjacent waters combine to form a complex, dynamic physical and biological system found nowhere else. When portions of floodplains are preserved in their natural state, or restored to it, they provide many benefits to both human and natural systems. Understanding and protecting the natural functions of floodplains helps reduce flood damage and protect resources.
Over the years, floodplains develop their own ways to handle flooding and erosion with natural features that provide floodwater storage and conveyance, reduce flood velocities and flood peaks, and curb sedimentation. Natural controls on flooding and erosion help to maintain water quality by filtering nutrients and impurities from runoff, processing organic wastes and moderating temperature fluctuations. These natural controls also contribute to recharging groundwater by promoting infiltration and refreshing aquifers, and by reducing the frequency and duration of low surface flows.
Floodplains enhance biological productivity by supporting a high rate of plant growth. This helps to maintain biodiversity and the integrity of ecosystems. Floodplains also provide excellent habitats for fish and wildlife by serving as breeding and feeding grounds. They also create and enhance waterfowl habitats, and help to protect habitats for rare and endangered species. Vegetation serves as a natural filter, trapping sediments and capturing pollutants; it also anchors stream banks, reducing bank erosion, and providing shade, which helps reduce water temperatures. In most cases, removing vegetation near a watercourse is a violation of the Albany Municipal Code.
People benefit from floodplains through the food they provide, the recreational opportunities they afford and the scientific knowledge gained in studying them. Wild and cultivated products are harvested in floodplains, which are enhanced agricultural land made rich by sediment deposits. They provide open space, which may be used to restore and enhance forest lands, or for recreational opportunities or simple enjoyment of their aesthetic beauty. Floodplains provide areas for scientific study and outdoor education. They contain cultural resources such as historic or archaeological sites, and thus provide opportunities for environmental and other kinds of studies.
These natural resources and functions can increase a community's overall quality of life, a role that often has been undervalued. By transforming stream and river floodplains from problem areas into value-added assets, the community can improve its quality of life. Parks, bike paths, open spaces, wildlife conservation areas and aesthetic features are important to citizens. Assets like these make the community more appealing to potential employers, investors, residents, property owners and tourists.
Whether or not to preserve floodplains in their natural areas or to restore them is a matter of ongoing public policy debate. Under the minimum requirements of the National Flood Insurance Program, the floodplain can be developed up to the edge of the floodway – that portion of the floodplain near the channel where flood velocities are greatest. Albany's Open Space zoning protects undeveloped floodplains along the Calapooia River and Oak Creek. Channelization projects in the 1970s increased the capacity sections of Periwinkle Creek, Cox Creek, Burkhart Creek and Truax Creek to carry the 100-year flood.
Do not dump or throw anything in ditches, creeks, or drains
A plugged channel cannot carry water, and when it rains, the excess water must go somewhere. Trash and vegetation dumped into drainageways degrades water quality and contributes to flooding. Dumping is a violation of the Albany Municipal Code. Even grass clippings and branches can accumulate and plug storm drains and channels.
From time to time it is necessary to remove obstacles from open channels to maintain the carrying capacity of the channel. An obstructed channel may overflow, exposing people and property to risk. Albany routinely inspects channels and culverts to remove obstacles as necessary. If you see dumping or debris in ditches, creeks or drains or report a channel obstacle, blocked culvert, or overflowing drainageway, contact the Public Works Operations Division (541-917-7600).
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