CLSports
Well-known member
- Joined
- May 29, 2007
- Messages
- 1,161
I have not seen the Big Spring Improvements yet, but I like them even less on a meadow spring creek. There is no place for these type of structures in this type of creek. A little bank stabilization is ok, but plunge pools and scour areas are not the best habitat IMO. Weeds and undercut banks are much better on these streams.A lot of times the rock structures (if unrestrained by wire caging, etc.) just fall victim to high water events anyway. There's a few of them on the Donegal in such condition.
Conversely, as far as in-stream structures that have improved habitat, one place I can think of is Big Spring Creek in Cumberland County. As many know, this is a classic spring creek with little natural holding structure other than weed beds and undercuts. The vane deflectors that were installed have created some habit where none previously existed.
Here's an interesting document on stream habitat improvements from the PFBC: https://www.fishandboat.com/Resource/Documents/habitat_improve_trout.pdf
I have seen rock vanes in place on a spring creek and all they achieved was to create a dam affect with a load of silt built up behind the rock. It did create a scoured area below the vane, but the fish habitat was not improved at all. I know 2 examples of this. One has been in place for decades and another maybe 5 or 6 years. The increased flow rate below these vanes has washed away any in-stream vegetation and it takes years to recover if it does at all.
Improve water quality and the rest will take care of itself.