Initial Report on what Caused Floods Released

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Town officials and residents from across the state, packed a meeting room in Bedford Tuesday evening.
They came to find out what caused the devastating floods in April of 07 and May of 06.
FEMA officials spent an hour showing charts and graphs of rainfall totals and intensity, snowmelt and other conditions leading up to the floods.
Engineer Brent McCarthy says two prior snowmelts, followed by more intense rain over a short period of time led to the April '07 floods.
In May of 06, it was heavy spring rains that lingered.
“so when we were asked why the 07 storm was worse, well the answer was it was some places, other places the 06 storm was worse, another point was how close these differences were to one another where on one basin you’d see a hundred year record event and another basin you wouldn’t”
Besides the weather conditions, FEMA looked at dam operations.
Flooded residents had complained that dams – particularly in April of 07 - made the flooding worse.
But McCarthy says for the most part, that wasn’t the case.
Mccarthy “ In general what we’re seeing in a number instances is that the dams don’t seem to be significantly adding to flooding there are certain circumstances where they do have an impact and we haven’t reached any general or firm conclusions yet, but that’s the general direction we’re going”
The study found that larger flood control dams like the Everett dam in Weare are capable of reducing flooding by 40-percent.
While smaller, old mill dams, known as run of the river dams, had little impact on floods.
McCarthy offered a comparison of the flood control capability of the two different types of dams.
“A flood control dam is like a garden hose going into a swimming pool, and a run of the river dam is like a fire hose going into a bathtub, so the fire hose just gushes all this water, fills the bathtub immediately, overtops the bathtub, the bathtub did nothing to hold back or prevent flooding.”
But the study did find some cases where earlier action by dam owners or emergency officials might have prevented damage.
Boards placed at the spillway of the dam, known as flashboards, can be automatically tripped or removed during flooding.
In the Souhegan River Basin, earlier removal of the flashboards at Otis Falls Dam could have prevented problems downstream in Greenville and parts of Wilton.
Along the Piscataquog, a railroad trestle near Kelly Falls Dam collected debris and may have led to flooding.
But many who attended the hearing were unsatisfied with initial findings.
Merrimack resident John Abagis was one of several victims who believe the dams are still the source of the problem.
" we had four point two feet of difference between the two floods, wasn’t that much precipitation, I understand the time of intensity, we think the dams have more to do with it."
For Allenstown resident Dennis Meuse, he says he wants to see immediate action.
"the only thing I’ve seen different from last April flood to here is 365 days have gone by, and I haven’t seen a single thing that’s changed any differently."
Meuse is particularly concerned about some of the smaller hydropower dams –
Their regulation is controlled by the Federal Energy Regulatory Commission, or FERC -- not FEMA or the state.
Bob Campbell with Salem’s Planning Board says those dams should be looked at.
" the people running those dams want to generate electricity, their interest is to have the water as high as possible and they’re causing injury and impact upstream by having the high water."
But FEMA officials say the study is not yet complete and they’re considering everything they hear from residents.
A final report and recommendations are scheduled for release in June.
For NHPR news, I’m Amy Quinton.