Wednesday, November 2, 2011

Fish Ladder Tour in the Watershed


VISITING FISH LADDERS
By Kirstie Jones
To see a map of the dams and fish ladders we toured click on this link.

Having just started interning at the NSRWA this past week, I was lucky enough to be able to accompany NSRWA staff as they met with fisheries biologists at several fish ladders in the area this past Tuesday. On this blustery but sunny fall morning we visited sites at Herring Brook in Pembroke, Veteran’s Park next to 139 in Marshfield, Chandler’s Pond, and two at the First Herring Brook Scituate Water Treatment Plant.
First Photo - New fish ladder Glover Mill Pond Dam on the Herring Brook, Pembroke

At our first site we met up with biologists from the Massachusetts Department of Fish and Game to examine a fish ladder that had been recently constructed in conjunction with a new dam in Herring Brook. Unlike the makeshift wood ladder that had originally been in place next to the old dam, this new Alaskan Steeppass ladder has much greater potential to aid fish passage during the herring spring migration. The dam, which creates a pond that serves a cranberry bog upstream, needed partial repairs and the fish ladder was completely rebuilt during the repair process. Prior to this project the dam was completely impassable for migrating fish and volunteers helped physically net the fish and transport them to trucks where they were driven upstream.

Second Photo: Sara Grad
y and Kirstie Jones from the NSRWA, Brad Chase, Ed Clarke and Louis from Division of Marine Fisheries, Phil Costello Contractor at the newly installed fish ladder and repaired dam at the Gorham Mill Pond in Pembroke on the Herring Brook.

As we saw on this trip, fish ladders are essential for giving fish a migratory route over most dams. There is resistance to removing dams, which would be an easier and environmentally-preferable solution, due to aesthetic, economic, and historical reasons. At the second site we visited, Veteran’s Memorial Park Dam on the South River, we learned that during the wedding season, (May - July), wooden boards in the dam are put in to raise the level of the pond for aesthetic purposes. This causes all the river’s flow to be directed down the fish ladder, making it impossible for fish to pass. The NSRWA, the Marshfield Conservation Agent, and the state fisheries biologists discussed recommendations for the park keepers to remove the boards for a certain period of time during the spring to allow the fish to pass and to stop flows out of a secondary pipe that exits the pond to avoid distracting the fish from heading for the ladder.

Third Photo: South River Veteran's park fish ladder and dam

At our next site upstream of the Veteran’s Park dam on the South River we visited the Chandler’s Pond Dam. No fish ladder currently exists, but during this meeting the possibility was discussed of constructing a new fish ladder in conjunction with a new bridge that is being planned on the site. The state biologists pointed out that from an engineering standpoint it would not be too difficult to incorporate these two projects so hopefully a new bridge for humans and a new ladder for fish will be the result of this project.

Fourth Photo: Dam at Chandler pond - not a likely candidate for fish passage!

















Fifth Photo: Spillway at Chandler Pond - Potential site for fish ladder













Our final stop was in my hometown of Scituate on the First Herring Brook which is part of the town’s water supply. During our visit to the water treatment plant and the Old Oaken Pond Dam I learned a lot about how town water is managed and how this can affect fish. Because the water levels have to be kept at a certain height in the reservoir, this often prevents the fish ladder from functioning at the levels it needs for the fish to migrate. However, with the cooperation of the Scituate Water Department it looks as if previous problems have been resolved and this spring the dam and ladder will be managed so as to let fish pass. During the summer we still need to work on conserving or finding new water to have enough water in the late summer and fall for the fish to migrate back out of the system.

Sixth Photo: First Herring Brook Old Oaken Bucket fish ladder and spillway
At the second Scituate fish ladder that we visited there is a lot more work to be done. This old ladder that accompanies the dam at Scituate’s larger reservoir on the First Herring Brook has some structural problems such as steep steps as well as debris blockage. Plans were made for local water department employees to work with state fisheries representatives to clear this debris to see if it is possible to return the ladder to some functioning capacity.

Seventh Photo: Reservoir First Herring Brook fish ladder
After trips to all these sites, I am far more aware of the many issues that surround dams and fish migration. I believe that many people, myself included, pass the man made ponds and reservoirs in this area and simply think of how beautiful they look, but we must also be aware of the repercussions our dams have on the fish that have been using these rivers and streams long before we were around to alter them for our convenience.


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