Building Responsibility in the Floodplain
Preventing increased damages
No development in the SFHA (Special Flood Hazard Area) and known flood prone areas shall create a damaging or potentially damaging increase in flood heights or velocity or threat to public health or safety.
In addition to the damage prevention requirements …
all buildings to be located in the SFHA shall be protected from the flood damage below the FPG (Flood Protection Grade). New construction and substantial improvements shall be constructed by methods and practices that minimize flood damage.
(common in both City and County Floodplain Ordinances)
KNOW YOUR FLOOD RISK
Please contact the Building Commission to find out if you are in a SFHA at: 435-7867, email@example.com, or Room 310 in the Civic Center on Martin L. King Jr . Blvd. because this will affect your permit application. Besides offering insurance, the National Flood Insurance Program (NFIP) has building requirements if you are located in a floodplain.
The NFIP is administered by the Federal Emergency Management Agency (FEMA). FEMA produces the Flood Insurance Rate Maps (FIRMs). The FIRMs contain a variety of information, including flood risk information called the Special Flood Hazard Areas (SFHA), which is floodway, the base (or 100-year) flood elevations, areas subject to inundation by the 1% (100-year) and 0.2% (500-year) floods. Revised FEMA (FIRMs) and Flood Insurance Study (FIS) became effective in 2011for our community..
The FIRMs that include the City Of Evansville and Vanderburgh County are viewable at:
As a condition of offering flood insurance to property owners, the City and County have adopted Floodplain Management Ordinances that govern and permit development in the floodplain. The ordinances address new construction requirements, remodeling and additions through one of the five Protecting Buildings methods and the state regulations on applying for permits in the floodway.
Prior to permitting the building of a new structure in the floodplain outside of the floodway, the Evansville-Vanderburgh Building Commission determines the base or regulatory flood elevation (BFE) for that specific lot. Then by City and County Ordinance they establish the minimum Flood Protection Grade (FPG) for the lowest floor of the building which is set at 2 feet above the regulatory flood elevation. This is usually done through the subdivision review process and recorded on the plat.
ELEVATION CERTIFICATES ARE REQUIRED
Elevation certificates are prepared by an Indiana Licensed Surveyor who verifies that the structure’s elevation is at that FPG. Elevation certificates are required during the construction process.
The National Flood Insurance Program (NFIP) requires the Building Commission to maintain a record of the elevation certificates for any new building or substantially improved building in the Special Flood Hazard Area (100 year floodplain). The NFIP also requires that elevation certificates are available for public inspection. Insurance companies utilize the certificates to determine flood insurance premiums for property owners within flood hazard zones.
Improvements to existing structures
Improvements to existing structures in the floodplain, require review by the Building Commission to determine if such improvements would constitute a "substantial improvement" as defined by City and County Ordinances. The Ordinances define substantial improvement as
… any reconstruction, rehabilitation, addition or other improvement to a structure, where those costs are equal to or greater than 40 percent of the market value of the structure before you begin the improvement. This includes structures which may have incurred “substantial damage” regardless of the actual repair work performed. This does not include any improvements to the structures that correct existing violations of state or local health, sanitary, or safety code requirements or any alteration of a “historic structure”, provided that the alteration does not remove it’s designation as a “historic structure”.
- The most important factor is that the top of the lowest floor of any new or substantially improved structure is at or above the flood protection grade (FPG).
FLOOD PROTECTION TECHNIQUES
Many of the following activities require a permit from the Evansville-Vanderburgh County Building Commission to meet the Protecting Buildings methods described in Section 16.10.080 of the City Municipal Code:
and in Section 18.04.080 of the County Codes:
Building Department staff will make site visits to advise of appropriate protection measures for both new and existing buildings, and will review plans to retrofit existing structures. The Building Commission can provide the names of Licensed Contractors in Evansville and Vanderburgh County. Please contact them at: 435-7867, firstname.lastname@example.org, or in Room 310 of the Civic Center on Martin L. King Jr . Blvd.
Modify the site to keep the floodwaters from reaching the building by:
These methods require contacting a Licensed Engineer so that this work is done properly and filing a site grading plan with the Building Commission according to the requirements listed at http://evansville.in.gov/index.aspx?page=2609
Modify the building so it can withstand the impacts of flooding
- Elevation - An existing structure can be raised to bring it to the FPG. This would reduce your insurance premiums. Elevating is required by code for “substantial improvement” projects. An Elevation Certificate is required to be filed with the Building Commission.
- Prevent sewer line backups by installing "check valves" or “back flow prevention devices” in sewer lines.
- Dry flood proofing with sealants - sometimes can be applied to walls and floors to keep water from penetrating the structure. This method can only be used in areas of shallow flooding (less than 2 or 3 feet) with minimal water velocities and where walls are above ground (not for basement walls).
- Wet floodproofing means letting the water in and removing everything that could be damaged. This method is used for areas that are not living areas such as basement or crawl spaces. Wet floodproofing is not feasible for one-story houses (slab on grade) because the flooded areas are the living areas.
- Closures - involve techniques for protecting gaps that have been left open for daily convenience, such as walks, doors and driveways. Place watertight closures over the doorways. This is not recommended if water will get over two feet deep.
- Basement flooding caused by saturated ground can be corrected by installing a footing drain around the foundation connected to a sump pump.
- Make certain that rain gutter downspouts are not connected to the footing drain or sanitary sewer. Make sure these downspouts drain away from the house but do not create a problem for your neighbors.
- Utility Protection - Flooding sometimes causes costly damage to utility systems. By elevating furnaces, heat pumps, water heaters, appliances, utility connections, etc., to the FPG, damage can be avoided.
Manufactured/Mobile Homes and Recreational Vehicles
- Also have to meet the elevation (FPG) requirements.
- There are specific location, anchoring and time limit requirements that have to be met.
- If there is a question about being located in a floodway or floodway permit requirements, the Building Commission will direct the applicant to contact the Indiana Department of Natural Resources (IDNR).
- By Indiana Code 14-28-1, Flood Control Act, a permit from the IDNR is required prior to the issuance of our local permits or approvals for any excavation, deposit, construction, or obstruction activity located in the floodway.
Contact the Indiana Department of Natural Resources Division of Water at toll free 1-877-928-3755 or water_inquiry@dnr.IN.go