The Hoquiam City Council recently updated the city’s flood ordinance to include a requirement that for all new construction, the lowest floor must be elevated three feet or more above the base flood elevation. The previous version of the ordinance required only one foot.
Base flood elevation is elevation to which floodwater can be expected to rise once every hundred years. There is a lot of property in the area that is within these 100-year flood zones, and those properties are difficult to sell or qualify for new development because of the flood insurance premiums required and the risk of the floods themselves.
Rising flood insurance rates were a driving factor behind the updated ordinance. By complying with the updated regulations, property owners can not only save themselves from future flood damage, but save a substantial amount of money on flood insurance premiums.
When asked about the increase costs to comply with the new standard, French Wetmore, a Certified Floodplain Manager whose consulting firm French &Associates is under contract with the Chehalis River Basin Flood Authority to assist communities with their floodplain management programs, said any increased costs in construction would be a lot cheaper than having to rebuild a badly flood damaged structure. Also, flood insurance premiums would be decreased.
“We found that the cost of elevating from one foot to three feet didn’t seem unreasonable,” said City Administrator Brian Shay. “And any cost would be paid back with the drop in flood insurance premiums.”
Wetmore stressed the value of setting floodplain regulations beyond those recommended by the National Flood Insurance Program. In his presentation to the council, he noted, “While a good start, minimum criteria will not keep flood losses in the Chehalis River Basin from increasing.” To illustrate why, he noted that the existing criteria “do not address the entire range of flood problems, only those areas mapped using Federal Emergency Management Agency mapping criteria. For the most part, the flood insurance rate maps in the Chehalis Basin are based on data from the 1970s.”
National flood insurance criteria also “neglect greater than 100-year flood events, unpredicted obstructions to flow, unmapped local hazards, and the effects of urbanization and a changing climate on flood levels,” added Wetmore. “For example, at the Grand Mound gauge (which the United States Geological Survey uses to measure water levels), the Chehalis River rose higher than the Flood Insurance Rate Map’s base flood elevation three times in the last 30 years (1990, 1996, and 2007).”
As he has done for Aberdeen, Montesano and other cities in the area, Wetmore provided the council with his recommendations in updating the city’s flood ordinance. They included:
Adopt historical flood of record data where the flood of record — the highest observed river stage at a given location during a certain time frame — is higher than that shown on the Flood Insurance Rate Map. Wetmore said it doesn’t make sense to protect people from a theoretical 100-year flood when actual flooding has been higher.
Where there is no recorded flood elevation for a property,a base flood elevation must be calculated by either the permit applicant or the community before a permit is issued for a new building or substantial improvement.
Construction cannot include filling in spaces within the floodplain unless water storage to make up for filling is provided. This does not need to apply to areas subject to coastal flooding.
New critical facilities would be prohibited from the 500-year floodplain or protected from damage and loss of access during a 500-year flood, which is basically a worst-case scenario flood, the most damaging to a greater area. For example, 100-year floods are those with a 10 percent chance of occurring any given year; a 500-year flood has only a 0.2 percent chance of occurring any given year. Examples of critical facilities include schools, hospitals, nursing homes, water treatment plants, hazardous materials sites, fire stations, and key bridges.
Anyone applying for a permit to elevate or improve a building on walls has to sign an agreement stating that the area below the flood protection elevation — which under the updated rules is classified as any area less than three feet above the 100-year flood base elevation — would not be converted to an incompatible use or with materials subject to water damage. Wetmore says this could be limited to enclosed areas higher than four feet, where there is room to tempt a future owner to remodel the floodable area.
Wetmore also recommended that all permit plan reviews, final inspections, and project approvals be conducted by a Certified Floodplain Manager. Shay said he was going through that certification process currently.
“Aberdeen and Hoquiam are interested in joining the Community Rating System,” said Wetmore. “The ordinance changes will help with that program, which will reduce flood insurance premiums for existing properties, too.” The National Flood Insurance Program’s Community Rating System is a voluntary incentive program that recognizes and encourages community floodplain management activities that exceed their requirements. Much like home insurance is cheaper in communities with the best fire and water departments, communties with the best flood plans would see lower flood insurance rates in this program.
Most, if not all, of Wetmore’s recommendations were put into the updated flood ordinance, which was approved by the council at their Jan. 23 meeting. The council also put an active date of Feb. 1 on the updated regulations.
