INCREASING ACCESSIBILITY IN THE BASIN
Increasing Accessibility in the basin
A major flood can inundate roadways and some, including I-5, have been closed for several days due to flooding. Roadway closures have a dramatic effect on emergency services and transportation and hinders community recovery efforts after an event. There are many potential transportation-related projects that could be implemented under any of LAND options. Design and extent of these projects would be dependent on a number of factors, including:
IDENTIFICATION OF THE STORM SEVERITY
assumptions and LAND concept(d) assumed for construction.
PRIORITIZATION OF PROJECTS
based on emergency access needs, protection of essential facilities and equity impacts.
COORDINATION WITH LOCAL JURISDICTIONS
to identify any needed changes to address updated flood elevations.
IDENTIFICATION OF ANY AMENDMENTS
for projects already in existing plans or if not within existing plans, completing plan amendments to include it in a future capital improvement program.
The following projects would likely be a combination of city, county, and state leadership, depending on who is currently responsible for roads and/or bridges and how construction would be funded. (NOTE: Projects 14-17 shown on the Map on page 28 still are still being defined and will be included in future analysis).
1. SOUTH SCHEUBER ROAD BRIDGE ($$$$$)
Install a new bridge from Fords Prairie across the Chehalis River to provide an alternative route for I-5 in the event of a closure. Concept layout of the new bridge is from South Scheuber Road to the south and Oakland Avenue to the north. Lewis County has studied this alignment in previous years.
2. SOUTH SCHEUBER ROAD–GRAF ROAD /MILITARY ROAD ($$)
Raise South Scheuber Road near the Graf Road/Military Road intersection to approximately 700 feet north of the intersection to maintain access to the hospital.
3. SOUTH SCHEUBER ROAD–WEST CONNECTION ($$$)
Raise sections of South Scheuber Road between State Route 6 and the Graf Road/ Military Road intersection. This project, in combination with projects 1 and 2 will complete an alternative route for I-5.
4. COOKS HILLS ROAD ($$$)
Raise Cooks Hill Road with structural fill to maintain access during an event. This project would also include raising utility castings and surface utilities (fire hydrants, communication and power cabinets and overhead utilities). This section of road does not have curb and gutter or sidewalks. Future improvements could include widening shoulders for a regional bike route and installing a fish friendly culvert or bridge at Scammon Creek.
5. STATE ROUTE 6 (SOUTH SCHEUBER ROAD TO I-5) ($$$$$)
Replace the existing bridge constructed in 1939 and elevate sections of Highway 6 to improve floodplain connections and minimize upstream raised water surface elevation.
6. WEST MAIN STREET ($$)
Raise West Main Street or construct a levee system in coordination with BNSF to provide a transportation connection from Chehalis to I-5 during flood events. This would require BNSF to raise their tracks, or construct a levee with a break for the rail and install a pump station on the shoulder. In the event of a flood, floodgates would be installed across the tracks.
7. KRESKY AVENUE (COST TBD)
Raise National to NE Kresky Avenue between its intersections with N National Avenue , or provide a series of levees, to maintain the roadway for emergency vehicles during a flood event. While the road is currently one-way northbound, it could also accommodate two-way traffic between Chehalis and Centralia during flood events.
8. SR 507 THROUGH CENTRALIA ($$) (ASSUMES LEVEE COSTS ARE IN OTHER PROJECTS)
SR 507 provides a connection from the existing Mellen Street Bridge area to the north of Centralia but is inundated in larger storm events. This project would provide levee protection for the roadway, but would also be coupled with other projects, such as projects 9 and 12.
9. PEARL STREET (SR 507) AND PEARL STREET BRIDGE ($$)
This section of roadway is in an area that frequently floods. This project would include replacing the existing 1928 bridge and raising the roadway to would allow for vehicle passage. The height of bridge raising would be determined in concert with Skookumchuck Levee configuration and modelling results.
10. REYNOLDS ROAD ($$$)
Reynolds Road provides an important east/west connection across I-5, but regularly floods near the Skookumchuck River. Raising the roadway with structural fi ll and increasing the width of the road prism would keep the road open and passable. Utility castings would be raised to the new asphalt road surface fi nish elevation and surface utilities (fire hydrants, communication and power cabinets and overhead utilities) would also be raised to the new roadway elevation. This section of road does not have formal curb gutter sidewalk. There is a current project to widen the roadway and add a center turn lane. The Lewis County project team could review the option to raise the roadway as part of their analysis. A levee would be needed near the Reynolds and BNSF undercrossing of I-5. A Skookumchuck levee north of Downing Road would be needed to keep Skookumchuck flows from entering Coffee Creek unless Skookumchuck flows are mitigated up stream. An alternative to raising the roadway would be to install a levee south of the roadway.
11. NEW MELLEN STREET BRIDGE–SOUTH ($$$$)
This project would be required if additional conveyance projects are constructed in the general vicinity of the existing Mellen Street Bridge. The project would construct a new bridge across the Chehalis valley from the Ellsbury Overpass to Military/Scheuber Road to provide an operational vehicular connection during the storm events. This project is included in Options 2 and 4 because those options would require removal and relocation of the existing Mellen Street Bridge and approaches.
12. RAISE S-12, CHEHALIS RESERVATION TO ROCHESTER (NEED COST)
This project would raise or protect SR-12 between the Chehalis Reservation and the city of Rochester to the west to preserve emergency access routes for the area.
13. RAISE ANDERSON ROAD (NEED COST)
Anderson Road is the primary access road to the Chehalis Reservation and is inundated during flood events, limiting access to key facilities off of the Reservation. This project would raise the roadway to maintain access during a flood event.
cost Ranges
$$$$$
$50M
$$$$
$25M–49M
$$$
$10M–24M
$$
$2M–10M
$
$2M
REDUCING FLOOD DAMAGE THROUGH SAFE STRUCTURES
The Voluntary Safe Structures approach establishes a framework for evaluating high-value or vulnerable structures within the floodplain to determine an appropriate method to address the potential damage to a structure in the event of a flood. Structures would be evaluated, scored, and grouped by level of risk and resulting action(s) needed to reduce damage from flooding. These levels include:
LEVEL 1: FLOOD INSURANCE.
Require flood insurance through the National Flood Insurance Program to property owners, renters, and businesses.
LEVEL 2: UTILITY RELOCATION.
Elevate utilities, including furnaces, air conditioners, appliances, electrical and plumbing systems above the flood elevation.
LEVEL 3: FLOOD-PROOF.
Modify structures using wet or dry methods: Wet flood-proofing. Water is allowed to enter the impacted area such as a crawl space to equalize the hydrostatic pressure.
Dry flood-proofing. The walls are made watertight, and all openings closed so water that reaches the building does not get inside. The building itself becomes the barrier to the passage of floodwaters.
LEVEL 4: STRUCTURE ELEVATION.
All damage-prone parts of the building are elevated above the flood protection level on a foundation intended to resist flood damage.
LEVEL 5A: ACQUISITION/DEMOLITION.
Property is purchased under a voluntary program and demolished, creating open space that preserves the natural function of the floodplain. Property owners and tenants will be compensated fairly, assuming pre-disaster conditions, for voluntary relocations or property acquisition. (Guiding Principle #2).
LEVEL 5B/RELOCATION:
Acquisition/Demolition & Relocation. Same as Level 5a, with relocation assistance. Options include physically moving a residential structure to a new location outside of a floodplain or identifying potential receiving areas for relocation outside of the floodplain. Financial incentives may be provided to housing developers, reducing housing costs to closely resemble buy-out costs.
STRUCTURE RISK ASSESSMENT CRITERIA
Preliminary risk assessment criteria will be used to identify valuable structures that may be in harm’s way and pose a risk to life and human safety. Valuable structures have been evaluated using the same.
Each structure would be evaluated using the following primary criteria:
Location of structure on the property.
Depth of water above the lowest floor of the building.
Velocity of water.
Repetitive loss/frequency where the structure has been identified as a repetitive loss property.
Cost effectiveness and if the mitigation measure exceeds the value of condition of the structure.
Secondary criteria include whether the property is near other mitigation projects, is adjacent to public land and each community’s goals and preferences.
ECONOMIC DEVELOPMENT AND LAND USE
Communities throughout the Chehalis Basin are required by the State of Washington to plan for future growth in their neighborhoods. Flood-prone areas may require building designs or elevations that reduce flood damage to a structure. Local land use codes could also limit development in flood-prone areas and identify existing structures that could be relocated elsewhere that can also accommodate future growth. These areas, call receiving areas, are geographic areas that can serve the needs of a community’s growing population and also be an option for current residents who voluntarily relocate outside the floodplain and want to remain in the community. Identifying potential receiving areas is a critical adaptation in land use planning. These areas are outside the floodplain, generally inside existing urban growth areas (UGA), are currently zoned or planned for residential development, are vacant or underutilized, are unconstrained by critical wetlands or habitat, and are located where there is potential to provide the necessary infrastructure to support the development.
Overall, Centralia and the qualifying Lewis County Local Areas of More Intensive Development (LAMIRDs) have the most potentially developable areas to serve the needs of growth and households displaced by flooding.
Under current zoning considerations (and factoring in the portion of area that is unlikely to develop due to market conditions and/or owner willingness to transact), potential receiving areas could have the capacity to accommodate between 5,290 to 6,220 housing units, or between 12,700 and 15,100 people. Areas within Centralia provide capacity for the largest number of households or population, followed by Chehalis and the Ground Mound UGA.
While these numbers may seem large, the Basin is growing rapidly and assumed to continue to do so in the future. The Town of Bucoda, City of Oakville, and the Grand Mound UGA might have sufficient developable land within their respective receiving areas to accommodate the expected population growth at current zoned densities, but Centralia, Chehalis, and Napavine might not be able to meet demand at current zoned densities.
Planned and future zoning densities are a local policy decision point, adopted by each individual city, town, or county council. Land use and policy considerations that each jurisdiction might want to address include:
- Consider the economic development opportunities of connecting to the river for recreation, allowing “river-oriented development that is highly walkable and with multiple housing types.
- Determine how to provide for more diversity in residential densities, with a variety of housing types to serve the wide variety of housing preferences.
- Plan for and provide a variety of amenities through subarea or master planning.
- Plan for affordability and equity. Lower-income households are at higher risk for displacement and providing housing at a variety of densities and income levels would improve equitable access for future growth and for households displaced by flooding.
RESILIENCY PROGRAM ELEMENTS
As climate change increases the intensity, frequency, and duration of major rain and snow events, the risks of living with a river will also increase.. We cannot completely prevent damage caused by outsized weather events. But as we begin to adopt our flood prevention and management plans, we can also build our capacity to recover and thrive after flood events.
Community resilience—the sustained ability of a community to withstand, adapt to and recover from adversity—has both social and material components. A resilient community provides residents and businesses with a sense of safety, connectedness, selfsufficiency, collective efficacy and hope for the future. Cultivating these qualities in advance of a crisis improves the likelihood that Chehalis Basin communities will successfully remain in the area and rebuild during the months and years it might take to fully recover.
There are also practical skills and plans that can be implemented before a disaster to improve the community’s ability to remain self-sustaining. Educating Basin residents about flood risks and projected floodplain boundaries, emergency escape routes, refuge areas, and resources such as resilience hubs is crucial to equipping each family to prepare and execute an emergency plan when disaster strikes.
Ongoing programming that supports resiliency can also become a part of community life. Training programs for trade skills such as carpentry and welding, survival skills such as first aid, and traditional skills such as canning, sewing, and cooking strengthen overall community resilience.
These programs can be linked to existing schools and education programs.
Each Basin community also needs a wellcoordinated early warning system (such as an expanded Chehalis Basin Flood Authority early warning system), paired with a way to identify nearby evacuation routes and community resilience hubs. While the region has an existing alert system, expanding broadcast cell phone alerts and networks of communication will continue to be an effective means to distribute early warnings, especially for Basin residents who live in isolated settings.
Resiliency hubs are neighborhood centers—often managed by community members in partnership with local governments—equipped to support residents, coordinate communication, and distribute resources before, during and after a crisis. They’re typically located in an existing facility such as a community center, school, or place of worship.
NEXT STEPS
The Chehalis Basin is providing important input on which potential solutions should be further explored. The project team will continue discussions with Basin communities in Spring 2023 to develop recommendations for short-, medium-, and longterm solutions to reduce flood damage for residents and businesses.