Floodplain FAQ

WHAT IS THE PURPOSE OF THE FLOODPLAIN CODE AMENDMENTS?

The Lane County Board of Commissioners adopted Ordinance No. 18-08, which is a modernization project of Lane Code (LC), including the floodplain code located within LC Chapters 10 and 16. Additionally, the Federal Emergency Management Agency (FEMA) requires specific code updates, which will allow Lane County to continue participation in the National Flood Insurance Program (NFIP). As such, Lane County staff have updated the County’s floodplain regulations at the direction of the Board and FEMA for the purpose of better protecting lives from flood hazard and reducing flood related property damage.

WHO IS MAKING THESE UPDATES AND WHAT IS THE PROCESS?

Following initial public outreach meetings in October of 2019, the Lane County Board of Commissioners directed staff to move forward with drafting amended language for LC 16.244 and 10.271. With the assistance of FEMA, staff drafted new language and will present this language to the Lane County Planning Commission at a work session and public hearing, and the Planning Commission will recommend action to the Board of Commissioners (approve, deny, modify, etc.). As a part of this process, there will be formal public hearings for which the public will be notified and given the opportunity to comment on the proposed amendments.

WHAT IS CHANGING?

In June of 2019, the Board of County Commissioners requested information on Lane County’s floodplain regulations and as part of this discussion, staff presented policy changes that could be adopted to make people and property safer from flooding. Simultaneously, FEMA directed the County to amend Lane Code to be in compliance with the NFIP. The Board directed staff to conduct public outreach on the proposed policy changes and move forward with the code amendments. The next section of this FAQ briefly summarizes the proposed policy changes. Alternatively, the proposed code language can be accessed on the project website: www.lanecounty.org/floodplaincode.  

IS MY PROPERTY LOCATED IN THE MAPPED FLOODPLAIN? 

You can view your property on the floodplain map at www.lanecounty.org/floodplaincode. Select the “Floodplain Map,” and follow the instructions to view the digital

floodplain maps on the Zone and Plan Map.

WHERE DO I LEARN MORE ABOUT THE CODE UPDATES? 

The project webpage can be accessed online at www.lanecounty.org/floodplaincode 

You may call our Planner-on-Duty at 541-682-3577,

or email staff at rachel.serslev@lanecountyor.gov

 


PROPOSED POLICY CHANGES:

WHAT IS OREGON’S MODEL FLOOD HAZARD ORDINANCE?

The State of Oregon Department of Land Conservation and Development (DLCD) coordinate the implementation of the NFIP in Oregon through an agreement with the FEMA. The Model Flood Hazard Ordinance was prepared by DLCD and has been reviewed and approved by FEMA. Adoption of the model ordinance language will ensure compliance with the minimum standards for participation in the NFIP. Staff propose to revise the floodplain code with the model ordinance language, as well as additional policy changes detailed on the next page.

WHAT IS COMPENSATORY STORAGE/BALANCED CUT AND FILL?

Fill can be any type of material (dirt, gravel, concrete, etc.), and when placed in the floodplain, it must receive a Floodplain Fill/Removal Permit in order to document the purpose of the fill and how much is being placed or removed. The proposed policy change, termed compensatory storage or balanced cut and fill, requires that any fill placed in the floodplain be mitigated by the removal of material in the same floodplain area or an area that is hydraulically connected. The intent of this policy is to address floodwaters displaced by fill material. For larger amounts of fill (200 cubic yards or more), a professional engineer, geologist or other expert must certify the location and amount of fill/excavation. Smaller amounts of fill (7 cubic yards to 200 cubic yards) are exempt from being certified by a professional but still need to be compensated, or minimal amounts of fill (7 cubic yards or less) are not required to be compensated at all but must still receive a fill permit.

WHAT IS A CUMULATIVE SUBSTANTIAL IMPROVEMENT?

A substantial improvement is any repair, reconstruction or improvement to a structure, the cost of which equals or exceeds 50 percent of the market value of the structure. When an alteration or replacement of an existing structure meets the definition of a substantial improvement, the entire structure must be improved to comply with current floodplain codes and permitting requirements. The proposed policy is to count improvements cumulatively over a time period of 10 years. This means that when an improvement is proposed, staff will review improvements to the structure from the past 10 years, and if the value of all improvements equal or exceed 50 percent of the market value of the structure, then the structure must be improved to meet floodplain design standards.

WHAT IS THE FLOODWAY AND WHAT ARE THE IMPLICATIONS OF LIMITING DEVELOPMENT THERE?

The floodway is an extremely hazardous area due to the velocity of flood waters that can carry debris and potential projectiles, and have high erosion potential. The regulatory floodway provides a mechanism for prohibiting development in the floodway unless it can be demonstrated that the development will not result in any increase in flood levels during a base flood discharge. Development within the floodway has a heightened potential to increase flood levels or change floodplains downstream from the development. Therefore, the proposed policy change is to prohibit development in the floodway with the exception of properties that are entirely floodway and the replacement of lawfully existing uses.

WHAT ARE THE BENEFITS AND COSTS OF ELEVATING A STRUCTURE?

A higher elevated structure reduces structural damage during a flood event, and can have significant cost reductions for flood insurance premiums. For example, in the ‘AE’ zone, requiring two feet of elevation instead of one foot can result in approximately a 34% reduction in flood insurance premiums on average. Generally, the long term benefits of elevation seem to outweigh the upfront costs of building higher. The proposed policy change is to increase elevation requirements in the ‘AE’ flood zone from one (1) foot above base flood elevation to two (2) feet above base flood elevation. In the ‘A’ flood zone, the regulation would change from elevating two (2) feet above highest adjacent grade to three (3) feet above highest adjacent grade.

WHAT ARE SUB-GRADE CRAWLSPACES AND WHAT ARE THE NEW DESIGN REQUIREMENTS?

A crawlspace foundation design is commonly used to elevate a residential structure in the floodplain, and a common construction practice is a sub-grade crawlspace, which is when the crawlspace is established below the natural ground level.  The proposed policy adopts design criteria for sub-grade crawlspaces to be compliant with FEMA’s guidance on best construction practices. The proposed design standards regulate the depth of the crawlspace and ensure drainage of floodwaters from the crawl space, so as to prevent problems with water accumulation, moisture damage and drainage.

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