Project to Help New Hampshire Coastal Communities Adapt to Climate Change

(289 :35 sloshing through water…)
Researchers with the New Hampshire Estuaries Project and Antioch New England College step into a huge culvert running under a road.
The stream flowing through here forms the headwaters of the Oyster River, which eventually heads into Great Bay.
289 1:00 (sound of talking getting measurements)
Derek Sowers with the New Hampshire Estuaries Project is measuring the length of the culvert, the opening of the culvert..
289 :07 the condition of the culvert, the type of material it’s made out of all these thing tell us how much water it can pass.
A culvert may sound like a strange place to be to prepare for the impacts of climate change.
But the wrong sized culvert during a severe storm can destroy roads, property and the environment surrounding it.
288 1:40 when you constrain the flows during a high flood event, it really basically shot guns the water out into the downstream habitat and causes a lot of bank erosion and changes the nature of the habitat.
That’s exactly what happened here two years ago during the Mother’s Day floods.
Researcher Michael Simpson with Antioch New England says damage from the 100-year storm is still visible.
288 3:40 you can see that you have the sediment and actually some of the old bridge out there in the flood plain, and because this was such a massive breakthrough is actually came up over the road, and created a whole new channel over there and that whole area in the flood plain is now buried in sand and gravel in the woods.
But the massive culvert that quickly replaced the old one is causing problems as well.
(nat sound)
The flow of the water coming out one end is eroding soil underneath the culvert.
Derek Sowers says it creates a steep drop which can be a big problem for fish and other aquatic life.
288 2:01 now fish that are in here, we actually do have native brook trout, nice cold water stream, now they can’t move between the upstream and downstream habitat because of that drop
And Researcher Michael Simpson expects Climate change will exacerbate these kinds of problems across the region.
288 13:30 the hundred year storm event now becomes the 25 year storm event, that is, the amount of water that comes in a 100 year storm event comes with frequency of what comes in a 25 year storm event, what becomes the 100-year storm event is the 250 year storm event.”
He says currently the state requires new culverts be built to withstand only 25-year storms.
But Simpson argues that coastal communities can prepare for climate change now, instead of responding to a crisis later.
286 110(the lifetime of the infrastructure of a corrugated culvert is about 30 years cement bridge is about 60 years, so if you consider that all of these things have a turnover life and they’re going to have to be replaced - we have 30 years or 40 years to change over this whole infrastructure which would what would happen anyway in a maintenance schedule)
(nat sound)
The Climate Ready Estuaries Project is hoping to convince community planners of the economic benefits that come with thinking ahead.

The data they’re collecting will determine which culverts in the watershed might fail first and how future development will affect runoff from storms.
They’ll also work with Durham, Madbury, Dover, Lee and Barrington officials to recommend culvert improvements based on risk and cost estimates.
The results will be shared with other communities and the 27 National Estuary Programs across the country.
For NHPR News, I’m Amy Quinton.