22.08.070 Flood hazard reduction | Bellingham Municipal Code

22.08.070 Flood hazard reduction.

1. Flood hazard reduction measures should not result in a net loss of ecological functions associated with the rivers and streams.

2. Flood hazard reduction measures should be consistent with comprehensive strategies that recognize the natural hydrogeological and biological processes of waterbodies and should seek to restore ecological functions within frequently flooded areas.

3. Development in frequently flooded areas should be prevented or removed to manage stormwater within the floodplain and to maintain or restore a stream system’s natural hydrological and geomorphological processes.

4. Bioengineered flood hazard reduction techniques are preferred and should be examined before structural measures are implemented.

5. The city should facilitate removal of artificial restrictions to natural channel migration, restoration of off-channel hydrological connections and recognize that seasonal flooding is an essential natural process.

6. Flood hazard reduction measures should be integrated with other regulations and programs, including (if applicable):

a. Chapter 15.40 BMC, Drainage;

b. Chapter 15.42 BMC, Stormwater Management;

c. Chapter 17.10 BMC, Building Codes;

d. Chapter 17.76 BMC, Construction in Floodplains;

e. Chapter 16.20 BMC, City of Bellingham Environmental Procedures;

f. Chapter 16.60 BMC, Land Clearing;

g. Chapter 16.70 BMC, Grading;

h. Chapter 16.55 BMC, Critical Areas;

i. BMC Title 23;

j. BMC Title 20, Land Use Development;

k. The National Flood Insurance Program;

l. 2007 update of the Wastershed Master Plan; and

m. 2006 Bellingham Comprehensive Plan.

1. When permitted, development within flood hazard (frequently flooded) areas shall achieve a no net loss of ecological function and shall comply with the applicable requirements in Chapter 17.76 BMC (Construction in Floodplains), Chapter 22.09 BMC and the following:

a. New development or new uses in shoreline jurisdiction, including the subdivision of land, shall not be established when it would require flood hazard reduction measures within the channel migration zone or floodway.

b. The uses and activities specified within BMC 22.08.010(B)(4), Shoreline buffers, may be appropriate and/or necessary within the channel migration zone or floodway provided they are:

i. Actions that protect or restore the ecosystem-wide processes or ecological functions.

ii. Bridges, utility lines, and other public utility and transportation structures where no other feasible alternative exists or the alternative would result in unreasonable and disproportionate cost. Where such structures are allowed, mitigation shall address impacted functions and processes in the affected section of watershed or drift cell.

iii. Repair and maintenance of an existing legal use; provided, that such actions do not cause significant ecological impacts or increase flood hazards to other uses.

iv. Modifications or additions to an existing nonagricultural legal use; provided, that channel migration is not further limited and that the new development includes appropriate protection of ecological functions.

v. Development in incorporated municipalities and designated urban growth areas where existing structures prevent active channel movement and flooding.

vi. Measures to reduce shoreline erosion when it can be demonstrated that the erosion rate exceeds that which would normally occur in a natural condition, and that the measure does not interfere with fluvial hydrological and geomorphological processes normally acting in natural conditions, and that the measure includes appropriate mitigation of impacts to ecological functions associated with the river or stream.

c. New structural flood hazard reduction measures shall be allowed in shoreline jurisdiction only when:

i. It can be demonstrated by a critical area report consistent with critical area report requirements as specified in Chapter 22.06 BMC including a scientific and engineering analysis that it is necessary to protect existing development;

ii. It can be demonstrated that nonstructural measures are not feasible;

iii. It can be demonstrated that there will be no net loss of shoreline ecological function including any mitigation required; and

iv. Appropriate vegetation conservation actions are undertaken consistent with this chapter and Chapter 22.09 BMC.

d. Structural flood hazard reduction measures shall be consistent with an adopted comprehensive flood hazard management plan that has been adopted by the city that evaluates cumulative impacts to the watershed system.

e. New structural flood hazard reduction measures shall be placed landward of the associated wetlands, and designated vegetation conservation areas, except for actions that increase ecological functions, such as wetland restoration, or as noted below. Provided, such flood hazard reduction projects may be authorized if it is determined that no other alternative to reduce flood hazard to existing development is feasible. The need for, and analysis of feasible alternatives to, structural improvements shall be documented through a critical area report including a geotechnical analysis.

f. New structural public flood hazard reduction measures, such as dikes and levees, shall be subject to the mitigation sequencing specified in this section and a federal Biological Assessment conducted by a federal agency responsible for reviewing actions related to a federally listed species. New structural public flood hazard reduction measures shall include the ability for the general public to access the shoreline unless said public access improvements would cause unavoidable health or safety hazards to the public, inherent and unavoidable security problems, the inability to mitigate impacts, unavoidable conflict with the proposed use, or a cost that is disproportionate and unreasonable to the total long-term cost of the development.

g. Removal of gravel, sediment and related materials from water bodies is prohibited except for fish and wildlife habitat restoration purposes or for flood management purposes. Removal of gravel for flood management purposes shall only be allowed if all the following conditions can be met:

i. The project is consistent with an adopted flood hazard reduction plan and with this title;

ii. The project does not result in a net loss of ecological functions, including natural sediment transport disruption and resulting impacts to salmon spawning areas, and is part of a comprehensive flood management solution; and

iii. A critical area report including a geomorphologic analysis demonstrates that extraction has a long-term benefit to flood hazard reduction. [Ord. 2018-12-036 § 47; Ord. 2013-02-005 § 2 (Exh. 1)].