Saltwater flowing up through the Horseshoe Pond Dam spillgate at high tide
One other significant observation we made this summer, is that Horseshoe Pond is under considerable tidal influence during low flow periods. During high tides above 4.8 feet we observed the flow of the river reversing, with the estuaries water pouring up into the pond. This was not an isolated event, in August and again from the fourth to the twelfth of September high tides pushed up into the pond. At night we observed juvenile flounder, grass shrimp, jelly fish, juvenile menhaden and elvers being drawn up into the pond. They would then flush back down to the estuary at the turn of the tide. We also found blue crabs approximately a quarter of a mile upstream of the dam.
The pond rises and falls significantly during these high tide periods. The full extent of the tidal influence appears to be quite some distance upstream of the dam.
We feel that any future fish passage or other alterations which may be proposed for the Horseshoe Pond Dam or surrounding area should take this new information into consideration.
This photo was taken from the top of the dam as the tide was coming in through the spillgate
This is a photo taken from the same vantage point about an hour after the above photo, note difference in water levels
For video clip of tide coming into Horseshoe Pond
For video clip of elvers (baby eels) climbing Horseshoe Pond Dam
For video clip of a lamprey below Horseshoe Pond Dam
Video clip of juvenile menhaden (a saltwater species) in Horseshoe Pond