Corey Clark, Chief Engineer of the Dam Bureau, NH DES, has a new report, this time about Burnham’s Marsh in the State Park:
I would like to make you aware that last week the Dam Bureau received a phone call from Pawtuckaway State Park about the conditions and concerns surrounding the level of the water at Burnhams Marsh within the State Park. (See map above, to the left of Big Island.)
The Dam Bureau visited the site and observed that the dike (it’s actually a dam, not a dike) at the north end of Burnhams Marsh was overtopping and in a state of failure due to the presence of a beaver dam constructed on top of the dam. Even though Burnhams Dike (NHDES dam number D184013) is within Pawtuckaway State Park (in yellow on the map above), it is owned by NH Fish and Game, so the responsibility for maintaining and repairing the dam lies with the NHDES Dam Bureau. On Friday of last week, I too visited the site to evaluate the condition of the dam and determine what could be done to alleviate the current threat to the main road in Pawtuckaway State Park.
After visiting the site and discussing the situation internally, the Dam Bureau has applied for and received Emergency Authorization through the NHDES Wetlands Bureau to remove Burnhams Dike. Due to the ongoing overtopping of the dike, it can no longer function safely and is at threat of failure. The embankment is severely eroded and without major repairs will continue to be structurally unstable. Additionally, the corrugated metal outlet pipe in the outlet works at the base of the dike is also on the verge of collapse and can no longer safely discharge water. If the dike were to fail, debris and sediment would inundate Pawtuckaway Lake near the Fundy Cove boat ramp/channel immediately downstream of Burnhams Dike.
While the removal of the dike will impact the water level of Burnhams Marsh and alleviate the current water inundating the main access road through Pawtuckaway State Park’s, it will also allow for the marsh to return to the natural configuration before the dike was constructed. The Dam Bureau will remove as much of the dike as possible so that any remaining portions of the manmade structure will no longer have the ability to impound water to a magnitude that could threaten infrastructure or Pawtuckaway Lake and is no longer a jurisdictional dam.
The Dam Bureau intends on starting this work during next week and completing the work during the week of April 21st -25th. This tight timeframe is necessary to alleviate the current situation, but also the work can be completed while Pawtuckaway Lake is lower than normal for this time of year.