Repairs to Lehigh River dam key to trout summer survival

Let’s hope the mail moves quickly.

If it does, it could be a life-saver for trout in the Lehigh
River.

During its meeting last week to announce the Francis E. Walter Dam
water release dates, officials with the U.S. Army Corps of
Engineers said they have ordered new bypass valves for the dam. The
devices would allow water to be drawn off the surface of the dam
and released into the Lehigh River.

That’s important.

The dam was built to release water from the bottom of the pool, and
that’s where the cold water is located. After a few releases in May
and early June, all of the cold water is exhausted. After that, the
heat of July and August warm the water in the dam, resulting in
releases that are nothing more than slugs of warm water down the
Lehigh River.

It’s the last thing the trout need.

When the cold water is released in May and June, the river is
already cool and the trout don’t need a respite from the warm
temperatures. But as summer drags on, the river warms up and the
trout are susceptible to heat stress. Releasing a slug of
sun-warmed water from the dam only adds to the tough
conditions.

But the bypass valves could be the answer. By releasing water from
the surface in May and June, the cooler water at the bottom of the
dam can be preserved and used in July and August when the river
runs hot. A release of cool water in the middle of summer will
lower the temperature of the river a bit and should go a long way
toward preventing temperatures from escalating far above 65
degrees, which can be fatal to trout.

During last week’s meeting, Corps officials said the valves were
being shipped from Italy and Germany. They were supposed to arrive
in December but still haven’t been delivered.

With the first water release scheduled for May 14, the valves had
better arrive soon. It’s a delivery that is critical for preserving
one of the top cold-water fisheries in the state, and one that
could mean the difference between life and death for the trout in
the Lehigh River this summer.

 

Categories: Pennsylvania – Tom Venesky

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