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Colorado winter storms and heavy rains have a big impact on flood potential. A floodplain is an area near a water source that is at a greater risk of being covered by flood water. Take a look at the Jefferson County Floodplains brochure with answers to some of the most frequently asked questions.
The local flood hazard is discussed in detail in FEMAs June 17, 2003 Flood Insurance Study (FIS). Read a portion of the FIS, including the Community Description and Principal Flood Problems.
Floods are one of the most common hazards in the United States. However, all floods are not alike. Riverine floods develop slowly, sometimes over a period of days. Flash floods can develop quickly, sometimes in just a few minutes, without any visible signs of rain. Flash floods also often have a dangerous wall of roaring water that carries a deadly cargo of rocks, mud and other debris, which can sweep away many things in its path. Overland flooding occurs outside a defined river or stream, such as when a levee or dam is breached. Flooding can also occur from a dam break producing effects similar to flash floods. Be aware of flood hazards no matter where you live, but especially if you live in a low lying area, near water or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry streambeds or low lying grounds that appear harmless in dry weather can flood.
Planning and Zoning staff can answers questions related to floodplain management, including determining if a property is located within a floodplain within Jefferson County. Copies of elevation certificates can be obtained on the Floodplains Elevation Certificates page or by contacting the Planning and Zoning Division.
For additional floodplain information or questions please contact the Jefferson County Planning and Zoning Division at 303-271-8700. In addition, see our FAQs regarding floodplains in Jefferson County.
The National Flood Insurance Program is a federal program that enables property owners to purchase insurance protection against losses from flooding.
The Insurance Program is administered by the Federal Insurance Administration, a part of the Federal Emergency Management Agency.
The Federal Insurance Administration has state-licensed insurance companies' agents and brokers sell flood insurance to you!
Contact your insurance agent for more information on the National Flood Insurance Program or call 1-888-FLOOD29.
There are a number of measures to take to protect your property from damage from a flood.
Floodplains in Jefferson County are the lower areas adjacent to rivers, lakes, and creeks that are periodically flooded at intervals of varying frequency. Floodplains are important components of their respective watersheds. Floodplains are hydrologically important, environmentally sensitive and ecologically productive areas within a watershed that perform many natural functions.
Floodplains contain a wealth of cultural and natural resources that are of enormous value to society. Riverine floodplains, such as the floodplains found in Jefferson County, vary in steepness, width, stream flow, sediment deposition and erosive characteristics. The natural functions that are associated with a particular floodplain depend in part on its location within this system. The frequency, duration and extent of flood events will also vary among different types of floodplains, dependent upon their hydrology, geology, and amount of floodplain development.
Floodplains are formed and modified by the dynamics of stream and river migration and periodic flooding. Although many riverine floodplains usually flood during the spring storms, they can also experience multiple flood events within the same year with duration varying from hours to days. Periodic flooding of riverine systems and the related processes of erosion and deposition determine, to a considerable extent, the shape of the floodplain; the depth and composition of soils; the type and density of vegetation; presence and extent of wetlands; richness and diversity of wildlife habitats; and depth to the groundwater.
The major flood conveyance component of the floodplain is the floodway. The National Flood Insurance Program defines the floodway as that area of the watercourse and adjacent floodplain necessary to carry the base flood without increasing the water surface elevation more than a designated amount (generally one foot). The base flood is the flood that has a one percent chance of being equaled or exceeded in a given year. Communities are required to prohibit development within the floodway that would cause an increase in flood heights. This requirement has the effect of limiting development in floodways that in turn helps to maintain some of the floodplain’s most important natural resources and functions.
There are a number of walking paths and bike paths throughout many of the floodplains in Jefferson County. These paths provide an opportunity for out citizens to enjoy the vegetation and wildlife that thrives in our floodplains.
Planning and Zoning staff can answers questions related to floodplain management, including in determining if a property is located within a floodplain within Jefferson County. In addition you can access jMap, the online Jefferson County interactive mapping application.
The most comprehensive weather information is obtained by listening to a NOAA Weather Radio. Weather Radio is operated by National Weather Service offices across the country and broadcasts frequently updated recordings containing current high climatological data. During threatening weather, live broadcasts issue warnings for winds, large hail, tornadoes, flash floods and winter storms. You can purchase a tone-alert NOAA Weather Radio at many local electronic stores.
The Emergency Alert System (EAS) is one tool that Jefferson County can use to warn its citizens in case of an impending disaster on participating radio and television stations. In most cases however, the National Weather Service has already activated EAS.
The other system we use more regularly is commonly referred to as “reverse 911”. To ensure that you phone number is registered to your home address for targeted emergency calls, please visit the Jefferson County Sheriff's Office CodeRED page.
We also regularly use other means of local media to put out critical information such as evacuation orders, sheltering information and other emergency messaging.
Always check with Jefferson County before building, grading, fencing or otherwise altering your property. Any work with our Floodplain Overlay District requires a Floodplain Permit from Jefferson County. Call Planning and Zoning at 303-271-8700 with any questions including reporting of an illegal floodplain development
"Substantial improvement" means any rehabilitation, addition, or other improvement of a building when the cost of the improvement equals or exceeds 50 percent of the market value of the building before start of construction of the improvement. Substantial improvements shall be counted cumulatively for a period of 10 years from the Start of Construction date of the first approved building permit. The term includes buildings that have incurred "substantial damage." "Substantial damage" means damage of any origin sustained by a building when the cost of restoring the building to its pre-damaged condition would equal or exceed 50 percent of the market value of the building before the damage occurred. Substantial damage is determined regardless of the actual repair work performed.
Substantial improvement or damage does not, however, include any project for improvement of a building to correct existing violations of State or local health, sanitary, or safety code specifications identified by local code enforcement officials as the minimum specifications necessary to assure safe living conditions. Also excluded from the substantial improvement requirement are alterations to historic buildings as defined by the NFIP.
Jefferson County prohibits impeding or interfering with the flow of storm water in the natural drainage ways, unimproved channels or watercourses, or improved ditches, channels or canals in such a manner as to cause flooding where it would not otherwise occur. This includes debris, branches, or other material that may interfere with the flow of water.
Call Planning and Zoning at 303-271-8700 with any questions regarding maintenance or including reporting of a violation.
Administration & Courts Facility 100 Jefferson County Parkway Golden, Colorado 80419 (303) 279-6511
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