Better stream crossings make for safer roads during stormsDecember 12, 2011 | Dams & Dam Removal, Floods & Floodplains
Here in the Northeast we saw a lot of damage to roads and streams from Hurricane Irene in Vermont, Massachusetts and New York.
In many places, road-stream crossings such as bridges and culverts were over topped and washed out, leaving large gaps in our road maps, some of which are still being repaired months later. As road crews race to repair roads before winter many of us witnessing the cleanup have taken a moment to ask how we can prevent this sort of damage in the future.
Even in normal years without major storms, improperly designed or installed bridges and culverts can over top and wash out roads during heavy rains and also often block fish and wildlife movement. The same issues that cause problems for wildlife, like high velocities racing through undersized culverts, can be problems for cars and people.
Undersized culverts are more likely to washout or over top, causing the road to collapse or becoming flooded during high water.
Our partners in Massachusetts have been working with local highway departments and river advocates in Western Massachusetts and had these two interesting examples of repeated washouts:
A stream crossing in Becket has washed out on two occasions in the last 6 years, most recently with Hurricane Irene.
On each occasion, the town has spent approximately $70,000 to replace the crossing with a 'temporary' crossing until funds can be found to replace with a 'permanent' span crossing projected to cost $300,000 – $400,000.
With the continuous wet weather in the northeast, the Town of Huntington has struggled with a particular crossing that has washed out three separate times since Hurricane Irene, washing approximately 2,500 tons of dirt into the stream in the last two months.
This same crossing washed out in 2007 with approximately 1,500 tons of dirt going into the brook. Ideally, the Town would love to see a larger culvert with a better angle installed. The impact of that road fill is significant to a small stream and the fish and wildlife that depend on it.
In contrast to these two examples, a previously failed culvert on nearby Bronson Brook in Worthington was replaced with a larger culvert in 2006.
It had no trouble passing the high flows from Irene and was safe for cars and pedestrians. American Rivers is working with our local and regional partners to understand how we can promote practices like Bronson Brook and prevent repeated failures.
Properly sized culverts allow water to flow and fish and wildlife to pass safely under our roads. Many of the regulations and funding sources are already in place and available to prevent these types of situations.
We need to make sure everyone, from the local highway departments up to the FEMA inspectors, understand the regulations and options so that we can install long-term sustainable crossings.