Tuesday, September 17, 2013

Dam Removal in MD

Interesting post on the MD DNR Angler's Log page from today...

"I have fished this part of the Patapsco River for about 10 years. Before the dam was removed, I would routinely catch 15- 20 fish per outing (smallmouth, sunfish, pumpkinseed, rockbass). I caught my largest smallmouth of 4 lbs in this stretch of the river. After the dam removal in late 2010, I fished this same part of the river and never saw one fish for the first year. The second year I might have caught 5 fish for the whole year. Went there on Saturday September 6th and for the first time I ended up catching over 30 fish including this 11-12 inch smallie. Hopefully, the river has recovered, and will produce better than it did with the dam in place. Have other dam removal projects required several years for the river to stabilize?
DNR Response: Yes, other river systems have taken multiple years to recover from a dam removals. In the Baraboo River (Wisconsin), macroinvertebrates and fish assemblages intially declined in abundance but then recovered within 2 years after the dam removal. In the Milwaukee River, removal of a mill dam resulted in the decrease of Smallmouth Bass abundance and biomass. However, after 5 years, water quality improved, smallmouth abundance and biomass increased, and biotic integrity changed from poor to good. Fish abundance responses to dam removals vary over time and according to specific site characteristics.
Your fishing report supports what we expected would happen to the fish community on the Patapsco River when the Simkins Dam was removed. From our monitoring of the river morphology and water quality, we confirmed that there was a shift from a lake-like ecology to a riverine ecology immediately after the dam was removed. The passive release of sand and gravel from behind the dam temporarily filled the river bottom and scour pools and eliminated areas where fish tend to congregate. With time, storm events and natural flow moved the sand and gravel downstream uncovering pools and creating cascades and riffles. This has resulted in the type of habitats preferred by river fish and most likely accounts for your improved catch rate. We expect that when Bloede Dam is removed, the dam furthest downstream on the Patapsco River, we will see additional improvements in water quality, river connectivity and fish communities."

Dam removal is a weird thing to most Marylanders, we don't have many of them and the ones we do have supply a great population of people with water through the reservoirs. We don't have big river run spawns with species and therefore its not looked at as much of a conservation cause. That said, I would be interested to see locations and numbers of dams in the state...may have to delve into this one.


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