I strongly believe that riverside Vermont municipalities, including Montpelier, should begin to transition to higher ground. I know that this suggestion engenders strong emotional and financial resistance. I am therefore heartened to have heard Sen. Bernie Sanders express the same opinion in a radio interview shortly after the recent flood.
Given the cascading climate catastrophes in the country, I suspect that it is only a matter of time before FEMA looks unfavorably at deliberately rebuilding in harm’s way. Why should any form of insurance cover rebuilding where the same kind of damage — be it forest fire, drought, or flood — is likely to recur?
I suggest the following flood-mitigation measures be considered for implementation over time. Careful research and planning should precede all changes to relocation and land use. Some of these measures, or similar approaches, are doubtless already encoded in existing law and code.
Flood Mitigation and Adaptation Measures — Personal Recommendations
At a minimum, building codes could facilitate transitions to higher ground by refusing a building permit where the value of any structure on the floodplain experiences major damage by flood, wind, or fire, if proposed repairs and flood avoidance improvement exceed 50% of its current assessed value. No new building permits should be given for sites on the floodplain. Variances should be allowed only for residential structures in cases of extreme hardship.
After Tropical Storm Irene, the state tentatively implemented a program of buying floodplain properties before a flood. About 100 properties have been acquired, according to a brief report, with some provision for relocation. I recommend greatly expanding that program, perhaps in partnership with municipalities, along with serious multi-jurisdictional efforts to provide relocation as close as possible to the original property. Relocation sites should be located with extreme concern for environmental protection, especially watershed and forest management.
To reduce distress from the above suggestion, I suggest a relocation site be surveyed for residents and businesses. The municipality might exchange the floodplain site for a relocated building site of equal value. This places the floodplain increasingly in common ownership and allows managing it in ways that support natural function.
All new roads should avoid steep angles with respect to contour and should be laid out with switchbacks on steep grades.
All new roads and, where practical, existing roads, should include swales along the shoulders.
Meanwhile, rebuilding in the floodplain should be elevated so the ground floor is above the peak flood elevation with a reasonable safety margin.
Building codes should require soil engineering and hydrogeology reports regarding susceptibility to subsidence. This is especially important with regard to retaining walls. Code should prohibit building on subsidence-susceptible soils without possibility of variance.
A report on tree species and species mixes that best stabilize soils against subsidence should be prepared by Vermont foresters and soil engineers in collaboration. This report should be written in terms readily understood by non-specialists and made available online and at little or no cost in print. Clearly this is a role our forestry, engineering, and agricultural colleges could fill with a multi-disciplinary approach.
Sewage treatment plants should be removed from floodplains, especially where adjacent to rivers, as the end of their useful lifespan nears or they experience major damage. Policies for dumping overflow into rivers should be reviewed with public comment.
Where storm water is delivered to sewage treatment plants, either the practice should be discontinued or provision made to divert storm drain output during risk of sewage discharge during flooding.
Toxins carried in floodwaters during the recent storm should be identified and their sources located. Then the risk of further contamination can be either eliminated or, where unavoidable, mitigated. It is obscene that floodwaters, nature’s way to enrich and build floodplain soils, contaminate them because of pollution from human activities.
Deforestation should require a permit signed off by a group that includes foresters and hydrologists as well as other planners. This provision should include greatly restricting or forbidding the practice of clear cutting.
Multiple Jurisdictional Decision Making and Action
Individual municipalities cannot manage flooding alone. The watershed begins at the highest elevations, with runoff accreting as it flows downhill, often crossing many political jurisdictions. The most effective mitigation of flood risk therefore begins at those elevations, which could be in a different county from communities downstream. Flood mitigation by the time water reaches rivers can be too late, too costly, and too temporary.
The material presented here represents the opinion of the author and does not reflect the opinions of The Bridge. Commentaries may be submitted to firstname.lastname@example.org. Preference is given to submissions by those who live in central Vermont. Submissions are encouraged to be 500 to 750 words in length.