A river, stream, lake, or drain may on occasion overflow their banks and inundate adjacent land areas. The land that is inundated by water is defined as a floodplain. In Michigan, and nationally, the term floodplain has come to mean the land area that will be inundated by the overflow of water resulting from a 100-year flood (a flood which has a 1% chance of occurring any given year). An estimated 6% of Michigan's land is flood-prone, including about 200,000 buildings.
The National Flood Insurance Program defines a "flood" as a general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waters or from the unusual and rapid accumulation or runoff of surface waters from any source.
The 100-year floodplain is the land adjacent to a river, lake or stream that will be inundated by water during a flood which has a 1% chance of occurring of being exceeded in any given year. Every river, lake or stream has a floodplain associated with it.
The flood elevations for rivers and streams are based on engineering analyses of the hydrology (how much water will run off the land during a flood event) of the watershed and the hydraulics (flow carrying capacity of a watercourse) of the river or stream.
The amount of runoff during a 100-year flood event is dependent on a number of factors, including rainfall (or snow melt), drainage area, vegetation cover, soil type, moisture content of the soil, land use, slope of land, and presence of wetlands & other flood storage areas. All of these factors are considered in computing the flow rates to be used in the hydraulic analysis. If the United States Geological Survey (USGS) maintains a gaging station (a location on a stream where discharge measurements are made and recorded) on the watercourse, this flow information will also be used in determining the 100-year flood flow.
The hydraulic analysis uses the flood flows to determine how high the water will get during the 100-year (1% chance) flood. The amount that a stream will rise during a flood event is dependent upon a number of factors such as the shape of the channel and the land adjacent to the channel, the slope of the stream, vegetation and obstructions in the stream, and man-made obstructions (including bridges, culverts, and dams). If past flood events have occurred in the area, the hydraulic model will be calibrated to reproduce past flood events. The hydraulic analysis will result in a flood profile being developed which will identify the 100-year flood elevation at any point along the reach of stream that has been studied.
Once the 100-year (1% chance) flood elevation is determined, the flood elevation is then plotted on a topographic map (a map which shows ground elevations referenced to mean sea level). The accuracy of the floodplain maps will depend on the accuracy of the topographic maps. The floodplain maps are only a guide as to whether or not a parcel is located in the floodplain. The most accurate method of determining the location of the floodplain requires an elevation survey to be done by a licensed land surveyor or a professional engineer.
The standard flood for floodplain management is the 1% chance (100-year) flood. It is possible to go a very long period of time without experiencing the 1% chance flood. It is also possible to have 1% chance floods two years in a row. There are areas along the Grand River that have not had a significant flood since 1904, while other areas of the state have received "100-year floods" in consecutive years. If you are located in the 100-year floodplain, we do not know when the 1% chance flood will occur, but at some point in time, it will occur.
If a house is located within the 100-year floodplain, it has a 26% chance of being flooded during the life of a 30-year mortgage. The same house during that same 30-year period has only a 1% chance of being damaged by fire.
There are various sources that may be checked to see if a floodplain map exists for your community.
Flood Insurance Rate Maps published by the Federal Emergency Management Agency (FEMA) are available on-line, or you can call the FEMA help line at 866-336-2627. You can also contact your community (City, Village or Township), your local library, or EGLE's Water Resources Division.
FEMA has not published maps for every community in Michigan. If a floodplain map does not exist for your area you can contact EGLE's Water Resources Division to see if your property is within the 100-year floodplain. To make a determination, EGLE will need a map showing your property location, (preferably with a legal description), and an estimate as to how high the property is above the water level of the river, lake or stream. This information should be emailed/mailed/faxed to the Water Resources Division district office.
You may contact your community/county building official, or the EGLE District Office. If FEMA has prepared a detailed flood insurance study, the 100-year flood elevation may be listed on the community's Flood Insurance Rate Map (FIRM). If a flood elevation has not been established by FEMA, you can contact the EGLE District office, and request a floodplain determination.
Any construction, fill or alteration of a floodplain of a river, stream, or drain which has a drainage area greater than or equal to 2 square miles will require a state floodplain permit under Part 31 of the Natural Resources and Environmental Protection Act. Such projects as building a house, placement of fill, installing a culvert or bridge, all would require a permit under Part 31.
In general, construction and fill may be permitted in the portions of the floodplain that are not floodway, provided local ordinance and building standards are met. In addition, compensating excavation must be provided that is equal to the volume of fill placed in the floodplain. Floodways are the channel of a river or stream and those portions of the floodplain adjoining the channel which are reasonably required to carry and discharge the 100 year flood; these are areas of moving water during times of flood. New residential construction is specifically prohibited in the floodway.
The current building codes in Michigan requires that new construction or substantially improved buildings within the 100-year floodplain have the lowest floor, elevated at least one-foot above the 100-year flood elevation. Basements that are below grade on all four sides must be 1 foot above the 100-year floodplain elevation.
The floodway includes the channel of a river or stream and area adjacent to the channel that will carry moving water during times of flood. This is a high hazard portion of the floodplain. The floodway is that portion of the floodplain that we see on television where the houses have been swept off their foundation. In addition to being a hazard to residents, the floodway also presents a hazard to rescue personnel.
Residential construction is prohibited within the floodway portion of the floodplain. Commercial construction may be permitted within the floodway, however, a hydraulic analysis may be required which demonstrates that the proposal will not harmfully increase flood stages or shift flood flows onto adjacent property owners.
If a Flood Insurance Study has been published for your community, the Flood Boundary and Floodway Map may be available on-line, the community may have a copy of the Flood Boundary and Floodway Map, or it may be available in your local library.
If a floodway map has not been prepared, the District Floodplain Engineer may be able to provide some guidance into the location of the floodway.
The term harmful interference or harmful increase is used to determine if a project can be permitted under Part 31. Under the Part 31 rules harmful interference means causing an increased stage or change in direction of flow of a river or stream that causes or is likely to cause damage to property, a threat to life, a threat of personal injury or the pollution, impairment, or destruction of water or other natural resources. If the proposed project does not cause a harmful interference, the project may be permitted under Part 31.
A harmful increase in flood stage can vary from site to site. It is possible in an urban setting, which currently experiences flooding problems, that any increase in flood stage will be harmful. Under this setting, it would have to be demonstrated that the project would not cause any increase in flood stage, for a range of discharges up to and including the 100-year flow.
If a project results in an increase in flood stages, and the increase is not contained on the property of the individual proposing the project, it would be necessary to obtain damage assessments from upstream property owners that will be impacted by the increased flood stages. The damage assessments would state that the upstream property owners are aware of the increased flood potential, and have no objections.
If the increased flood stage is confined to the individual's property, or it is considered not harmful, the project may be permitted under Part 31.
The cost to apply for a permit under Part 31 to alter the floodplain varies depending on what is being proposed. If the project is not located within the floodway portion of the floodplain, the project would meet the "minor" category, and the application fee is $100.
If the project will involve work within the floodway, but is something that can be permitted without having a hydraulic analysis prepared, the application fee is $500.
If the project will involve work within the floodway, but will require the submittal of a hydraulic analysis to demonstrate the effects of the floodway alteration, the application and review fee is $2000.
Additional information:
A hydraulic analysis may be required when a project is proposed within the floodway portion of the floodplain, and it is necessary to demonstrate the impacts on flood stages. The analysis will require a detailed site plan, stream valley cross sections at locations where the proposed alteration will occur, representative photographs of the channel and overbank areas, and detailed hydraulic computations prepared by a professional engineer licensed in Michigan.
If the drainage area of the stream is 2 square miles or greater, a permit will be required for the culvert installation. Whether or not a permit could be issued under Part 31 will depend on what impact the proposed culvert will have on upstream flood stages.
The culvert can be reviewed as a minor project (no hydraulic analysis required) if the proposed culvert crossing meets the minor project criteria.
If the culvert will not meet the minor project category, a hydraulic analysis may be required to demonstrate that the project will not cause a harmful increase onto adjacent property owners. You should contact the district floodplain engineer to discuss the project. Please keep in mind that there are different requirements for a minor project category under Part 301, Inland Lakes and Streams.
If the addition will increase the size of the "foot-print" of the house, and the addition is in the floodplain, a permit under Part 31 will be required. If the addition will not increase the size of the foot-print of the building (such as adding a second story), a permit under Part 31 will not be required. It should be noted that local building codes will require that the addition be elevated above the 100-year flood elevation.
A state floodplain (Part 31) permit is not required for the construction of a house within the floodplain of a lake, provided the construction is not being proposed on the inlet or outlet of the lake. However, the local building code will require that the house be elevated above the 100-year flood elevation.
Following are other activities that do not require a permit under Part 31:
It should be noted that while these activities do not require a state floodplain permit, other state, county or local permits might still be required.
If the drainage area of the county drain is 2 square miles or greater, and the culvert is not being installed under the authority of Act 40 of the Michigan Drain Code, a permit will be required from EGLE under Part 31.
The runoff from individual lots is considered a local drainage issue. You may want to talk with your neighbor to see if there is something that can be done to remedy the problem. You may also want to contact the community to see if there is assistance that can be provided by the community or the county. In some instances, the only remedy is through the court system to try to correct the situation.
Visit EGLE's Floodplain Management/National Flood Insurance web page or FEMA's National Flood Insurance Program Frequently Asked Questions web page for a more detailed list of questions and answers.
The NFIP is a federal program enabling property owners to purchase flood insurance. The federal government makes flood insurance available to communities that agree to enforce requirements that will reduce future flood losses to new construction within the special flood hazard area (100-year floodplain). The NFIP came about following many years and billions of dollars spent on constructing dams, levees, and sea walls to try to reduce flood losses, only to see flood losses continue to rise.
The goal of the NFIP is to mitigate future flood damages by requiring proper construction methods, and to provide a method of insuring against damages due to flooding.
Home owners insurance does not include damage due to flooding. Flood insurance is only available through the National Flood Insurance Program. There are some exceptions such as Lloyds of London but the cost is significantly higher.
Flood insurance is available only within communities that participate in the National Flood Insurance Program (NFIP). If your community participates in the NFIP, any licensed insurance agent can sell flood insurance, if they choose to. You may want to check with the insurance agent that handles your homeowners policy. The flood insurance rates are set by the Federal Insurance Administration, and should not vary from agent to agent.
You may want to contact your community, contact EGLE, or obtain a National Flood Insurance Program community status list from the FEMA website.
Under the National Flood Insurance Program Reform Act, if a building securing a loan is located within a federally identified special flood hazard area (100-year floodplain), and the lender is federally regulated, supervised or insured, flood insurance must be required as a condition of the loan. Under the Act, if the lender makes a loan on a structure that is in the special flood hazard area and does not require the flood insurance, they will be subject to fines.
The Special flood hazard area is another term for the 100-year (1% chance) floodplain. The Federal Emergency Management Agency (FEMA) has published Flood Insurance Rate Maps (FIRMs) which identify special flood hazard areas throughout the United States. Within Michigan there are floodplain maps published for about 750 communities.
If community does not have a flood insurance rate map, it means that there are currently no federally identified special flood hazard areas in the community. There would be no federal mandatory flood insurance purchase requirements as a condition of a loan. However, there is a floodplain associated with every river, lake, stream, or drain, even if it has not been identified by the FEMA. It is possible that a flood insurance rate map could be published at a later date. If you are considering purchasing property close to a watercourse, you may want to talk with local, county and state officials to determine if the area may be prone to flooding, and if there are any building restrictions or permit requirements. At the state level, you should contact the EGLE district floodplain engineer.
Flood Insurance is available only in a community that participates in the National flood Insurance Program. Because of the state laws and building codes in effect in Michigan, every community meets the minimum requirements to participate in the NFIP. To join the NFIP, a community would have to pass a resolution indicating they would like to join, pass a resolution directing the building official to strictly enforce the flood resistant construction standards of the building code, and submit the application. In some communities, the county does the building inspection. In those communities, an agreement must be signed by the county and the community indicating building inspection is provided by the county. There is no fee or cost associated with joining the NFIP. There would be record keeping requirements for new construction within the floodplain.
To demonstrate that your house is not in the floodplain, the first thing is to get a copy of the Flood Insurance Rate Map (FIRM) for your community. If your house is shown to be within the special flood hazard area on the map, the lender must require the purchase of flood insurance. If only a portion of your property is within the floodplain, but the house is not in the floodplain, there are no federal requirements for the purchase of flood insurance. If you feel that the FIRM does not show your house to be within the special flood hazard area, you should contact your lender to make sure that they have correctly located your property and your house.
If the house is shown to be within the floodplain on the FIRM, the only way to remove the flood insurance purchase requirement is to apply to FEMA for a letter of map amendment (LOMA). A LOMA requires that the property owner submit elevation information that demonstrates that the structure is above the 100-year flood elevation. The elevation certificate and the LOMA application can be downloaded from FEMA's website.
If the house was constructed before the date of the FIRM, it would have to be shown that the lowest natural ground elevation next to the house is above the 100-year flood elevation. If the house was constructed after the date of the FIRM, it would have to be demonstrated that the lowest ground elevation next to the house, and the lowest floor elevation (including basement) are above the 100-year flood elevation. It must also be demonstrated that no fill was placed to raise the lowest adjacent ground elevation above the 100-year floodplain elevation.
If you have questions on the LOMA process, you can also call the FEMA's toll-free help line at 1-877-336-2627.
Another common false statement that is received is: "my insurance agent said I could not buy flood insurance because I do not live in the floodplain". Actually, neither statement is correct. Flood insurance is available to any resident of a community that participates in the National Flood Insurance Program. It does not matter if you live in or out of the floodplain (special flood hazard area). However, the rates for the flood insurance are higher for property that is within the special flood hazard area (100-year floodplain).
The cost of flood insurance varies depending on how much is being insured, when the house was built, if the house has a basement, and the elevation of the lowest floor of the house.
Please talk with your insurance agent, to discuss your particular situation.
Federal mandatory flood insurance purchase requirements only apply to houses located within the 100-year floodplain. Zone X (or on some of the older flood insurance rate maps zones B and C) is outside of the 100-year floodplain. Flood insurance is available in zone X at a lower rate, but there are no federal requirements for the purchase of flood insurance as a condition of a loan. If the flood insurance is being required on a house in zone X as a condition of a loan, it is at the individual lender's discretion, another lender may not require flood insurance.
It should be noted that about 40% of the flood insurance claims occur outside of the 100-year floodplain. Even though a house may not be located in the 100-year floodplain, there is no guarantee that it will not flood.
A community can withdraw from the National Flood Insurance Program at any time by simply passing a resolution, and notifying FEMA of their desire to drop out of the NFIP.
However, before dropping out of the NFIP, a community must consider the ramifications:
Once you apply for flood insurance, there is a 30-day waiting period. The exception to the waiting period would involve new real estate transactions, when title is being transferred. Flood Insurance would become effective once the title is transferred.
If you have other questions on the floodplain permitting process or the National Flood Insurance Program in Michigan, find your local Floodplain Staff Contact.
