Division of
Engineering & Roads

1026 W. Broadway Ave.
Spokane, WA 99260-0170
Contact Us
Skip Navigation Links

Latest News

Skip Navigation Links
Bigelow Gulch Phase 4 & 5 Right of Way - Request for Qualifications
All Engineers news...
Print this page 
Email this page to a friend 

Your questions, comments, and suggestions about this page help us evaluate how well we are doing at providing clear and concise information.

The suggestion field is required. Please provide an email address or contact information if you would like a response.



Floodplain Development Permit

Floodplain Development Permit E-10 PDF
 


Facts and Floodplain Requirements

What is a floodplain?

Land areas adjoining a river, stream, water-course, major drainageway, wetland, low lying area, or lake that is likely to flood.

What is floodplain management?

Methods used for preserving the natural function of floodplains and reducing flood damage through floodplain management regulations.

What is a 100-year flood?

This term is a statistical designation meaning that there is a 1-in-100 or 1% chance that a flood this size will happen during any given year.

What is a floodplain?

Land areas adjoining a river, stream, water-course, major drainageway, wetland, low lying area, or lake that is likely to flood.

What is floodplain management?

Methods used for preserving the natural function of floodplains and reducing flood damage through floodplain management regulations.

What is a 100-year flood?

This term is a statistical designation meaning that there is a 1-in-100 or 1% chance that a flood this size will happen during any given year.

Who determines where these floodplains are located?

The floodplains in Spokane County have been identified on maps, which were produced by the Federal Emergency Management Agency (FEMA) as part of the National Flood Insurance Program (NFIP). The maps are available for review at the Spokane County Engineer’s Office or online at: www.fema.org

Why does Spokane County have floodplain regulations?

When Spokane County joined the NFIP, we were required to adopt and enforce floodplain management regulations for participation. By participating in the NFIP, property owners in Spokane County are able to purchase insurance against flood losses.

Is development allowed in a floodplain?

Yes, but all development is subject to the requirements of the Spokane County Flood Ordinance and the NFIP.

When is a Floodplain Development Permit required?

Developing property, all or a portion of which is in a regulated floodplain, requires a Floodplain Development Permit. This permit will identify the specific requirements for each proposed project. Prior to Floodplain Permit release, all plans must be reviewed to ensure that they meet the requirements of the Spokane County Flood Ordinance.

What is considered development?

Development includes, but is not limited to buildings, homes, manufactured and mobile homes, other structures, bridges, culverts, dredging, filling, grading, paving, excavation, docks, boat lifts, seawalls, bulkheads, etc.

Floodplain Requirements “A” Zones:

“A” Zone is an area that has been determined to be in the 100-year flood which may or may not have base flood elevations and flood hazard factors determined. A more complete description of “A” Zone is located on each Flood Insurance Rate Map (FIRM) key.

What are the floodplain requirements for my residential/commercial structure?

In areas where flood elevations are known, the lowest floor including basement must be a least one (1) foot above the base flood elevation. Base flood elevation, also known as the BFE or 100-year flood, is the term used for a flood having a one (1) percent chance of being equaled or exceeded in any given year and the elevation at which it may occur.

If flood elevations are not known in the area you are developing, a site inspection by the Spokane County Floodplain Management staff is required. If it is not clear that the proposed home will be outside of the floodplain, the applicant is asked if they could relocate to a safer (clearly out of the floodplain) area upon the property. The applicant may also hire an engineer to more precisely delineate the floodplain and establish a BFE for the property. Construction of the lowest floor including basement must be one (1) foot above the newly established BFE. Residential homes must elevate above the BFE and commercial structures have the option to flood proof above the BFE.

What are the floodplain requirements for dock projects?

Dock projects do not require a Floodplain Development Permit unless fill is being imported to the site or docks are fixed (not floating). Fill includes, but is not limited to gravel, sand, rock, concrete pads, bulkheads, seawalls, rip rap, etc.

What are the floodplain requirements for fill, grading, excavation and crossing structures?

Applicant discusses the project with the Floodplain Coordinator and the requirements for the permit are given.

In areas where flood elevations are unknown (unnumbered “A” Zones), the applicant’s engineer must show that the fill, bridge or culvert will not increase the BFE by more than one (1) foot at any point.

In areas where the flood elevation is known (numbered “A” and “AE” Zones) but floodway is not designated, the applicant’s engineer must show that the fill, bridge or culvert will not increase the BFE by more than one-tenth (1/10th) of a foot at any point.

In both cases above, adjacent properties must not be impacted without the owner’s permission.

For areas where flood elevations are known (numbered “A” and “AE” Zones) and a floodway is designated, filling in a floodplain requires the applicant’s engineer to show that the fill will not increase the BFE. For crossing structures, bridges must span the floodplain or the applicant’s engineer must show that it is stable during 100-year flood flows/velocities and does not increase the BFE. Culverts need to be designed by an engineer to pass the 100-year flood flows without increasing the BFE. A bond is taken to ensure the structure or grading/fill/excavation is built according to the plans. If excavation is planned, the requirement is generally to remove the spoil (excavated) material from the floodplain to an upland location.

“B” ZONES:

“B” Zone is the area that lies between the 100-year flood and 500-year flood. Flooding depth and contributing drainage area is also addressed in the “B” Zone. A more complete description of “B” Zone is located on each FIRM key.

My property is associated with a “B” Zone floodplain.

“B” Zone floodplains are treated the same as unnumbered “A” Zone floodplains. For “B” Zones, generally, no flood insurance is required.

“C” ZONES:

“C” Zone are areas of minimal flooding.

My property is associated with a “C” Zone.

If your property is located in a “C” Zone no Floodplain Development Permit is required.

ADDITIONS OR IMPROVEMENTS TO STRUCTURES:

Any repair, reconstruction or improvement to a structure, the cost of which equals or exceeds fifty (50) percent of the fair market value of the structure requires a Floodplain Development Permit. Any addition, no matter what the cost, will also require a Floodplain Development Permit. All other above conditions apply.

FLOOD PROOFING:

Residential homes must elevate above the BFE and commercial structures have the option to flood proof above the BFE. A licensed engineer or landscape architect must design the flood proofing.

FEES:

For Floodplain Development Permits issued with a known elevation, a fee of $35.00 and a bond of $750.00 will be charged. The bond will be refunded upon presentation, to Spokane County, of a completed Elevation Certificate. Floodplain Development Permits issued with an unknown elevation are $57.00 and will require a site visit.

What is an Elevation Certificate?

The Elevation Certificate is a form used by FEMA that records the elevation of the lowest floor for structures built on property all or a portion of which is in a regulated floodplain.

Why is an Elevation Certificate required?

(1) Our Flood Ordinance requires it to document compliance with permit conditions. (2) Elevation Certificates are the only official document used by FEMA to determine whether a structure is inside or outside a floodplain. (3) Elevation Certificates are used to determine the proper rate when purchasing flood insurance.

When is an Elevation Certificate required?

If the floodplain associated with your structure has flood elevations, then an Elevation Certificate is required upon completion of construction.

Why is an Elevation Certification bond taken?

The bond ensures that the applicant will complete and return an Elevation Certificate to the County once the structure is built. The bond is taken during issuance of a Floodplain Development Permit and will be returned to the applicant after we receive the completed Elevation Certificate.

Who can fill out an Elevation Certificate?

Elevation Certificates must be completed and stamped by a surveyor licensed in the State of Washington.

ENVIRONMENTAL REVIEW

Prior to issuing a Floodplain Development Permit a State Environmental Policy Act Checklist (SEPA) process may need to be completed. See Spokane County Building and Code Enforcement Bulletin, B-49, “Environmental Review.”

MISCELLANEOUS

Please note, other permits may be required from any one or more of the agencies listed below:

Environmental Programs

509/477-3600 Bus | 509/477-7478 Fax
Request for Information