Little Lehigh decline

[Chaz]

troutbert wrote:
Have their been changes in the physical habitat, especially pool habitat?

If so, what has caused these changes?

Trout need good holding water. If you want to have good trout populations, you need depth and cover.

If a stream is flat, shallow, featureless, the trout populations will be low, even when water quality and quantity are good.

Most of the stream mileage in developed areas is highly artificial, highly altered, i.e. channels have been moved, simplified, straightened, suffered loss of large woody debris, floodplains developed, etc.

Under those circumstances, most of the stream's ability to create good pool and cover habitat through natural processes is lost. So, you may have to create man-made habitat, if you are going to have any at all.

Significant change in habitat has resulted from flooding which is in part the result of continued development in the LV. Where once there were pools there is now silt and sediment. where once there were deep runs there is now sediment.
The City of Allentown has a policy of removing all fallen trees from the creek as soon after they fall as possible, aggravating the situation.

 

[franklin]

troutbert wrote:
All of this is very confusing.

The bottom line questions:

1) Has the wild brown trout population on the Little Lehigh really gone down substantially, or not?

PFBC surveys should be able to determine the answer.

2) If the wild trout population has gone down substantially, what is the cause?

https://www.google.com/maps/@40.5329183,-75.5679615,3480m/data=!3m1!1e3

The large part of this development came in the pat 20 years.

(Go to aerial view.)