EVERETT — Snohomish County’s rules for building near potential landslide dangers remain more or less unchanged from when the deadly Oso mudslide hit a year ago.
The County Council is likely to enact stricter regulations by mid-year, beyond the temporary construction ban already in place for the immediate Oso slide area.
Recommendations include expanding the areas near steep slopes where the county would require geotechnical engineering reports before issuing building permits. A summary of the engineer’s report would need to be recorded on the title of the property. The property owner also would have to sign a waiver, holding the county harmless should anything go wrong, before a building permit would be issued.
“When you build within a landslide area, there’s going to be more analysis required,” county permitting manager Tom Rowe said.
The new landslide hazard rules are part of the regular update to the county’s critical areas regulations, a requirement of the state’s Growth Management Act. The update includes other sensitive areas, such as wetlands and aquifer recharge zones. The existing critical areas rules took effect in October 2007.
Changes that planning commissioners recommended last month would broaden the county’s definition for landslide hazard areas, and where geologic analysis would be required.
That wouldn’t necessary halt construction near steep slopes.
The new rules would expand the area around certain steep slopes that the county considers geologically hazardous. For a 150-foot-tall hillside, for example, that area would cover up to 300 feet from the toe of the slope and 150 feet from the top. Under the old rules, the hazard area would have extended 75 feet from the bottom of the slope and 50 feet from the top.
The new rules would apply to slopes of 10 feet or higher and if they are 33 percent or steeper, with certain geologic characteristics. Evidence of past landslides or flood dangers also could trigger slope studies. Land in the Stillaguamish Valley has been sliding since the Pleistocene Epoch.
The new rules would allow the county planning director to extend a landslide hazard area under certain conditions.
“I believe we’ve always had the ability to ask for that additional information,” Rowe said. “This just means we’ll be requiring it.”
It’s unclear whether the proposed code changes would have saved any lives in Oso on March 22, 2014, when the collapse of the 600-foot Hazel Hill pushed debris nearly a mile.
While permanent rules still are being discussed, a moratorium on building or rebuilding in the immediate slide area has been in place for more than nine months. The temporary ban will remain in effect until June 17, unless the County Council opts for renewal. It also covers areas to the east where the slide is thought to have increased flood dangers along the North Fork Stillaguamish River.
County Council Chairman Dave Somers wanted to consider further restrictions in slide-risk areas, but was unable to convince other council members to even discuss them in public. Builders and real estate agents had strongly opposed the more drastic changes.
If the county succeeds in buying out damaged property in the slide and flood zones, the building moratorium there would become moot. The county has been seeking $12.8 million in federal funds to buy 135 land parcels, including many properties that used to belong to the 43 people who died in the slide. County staff hope to get an answer from the Federal Emergency Management Agency in late spring or early summer.
The critical areas update would be the first phase of landslide-safety reforms the county planning department has outlined.
A second phase would expand on any changes the Legislature makes during this year’s session, which is scheduled to wrap up in April.
As far as land-use regulations go, the focus for state lawmakers has been increasing the ability to map potential landslide areas and interpret the data.
Mapping and geological science are top priorities in the report produced in December by the joint commission that Gov. Jay Insee and Snohomish County Executive John Lovick convened to study the landslide.
Legislators are working on a bill to make the state Department of Natural Resources a clearinghouse for landslide mapping data so governments and private industry can use it.
Commissioners had suggested prioritizing mapping in several areas: the mudslide-prone Seattle-Everett rail corridor, the I-5 corridor, mountain highways, urban areas and state forests.
Inslee’s proposed budget includes $36 million for slide mitigation and funding for advanced LiDAR, which stands for Light Detection and Ranging imagery. That money is part of his 12-year transportation package.
Only a few areas of the state have been mapped using LiDAR, and none of the charts are as detailed as experts recommend.
Inslee’s operating budget also set aside some money for creating a Hazard Identification Institute, which he envisions as a repository for geological hazard information in Washington.