|The willet (left) and Savannah sparrow are just two of the species that have returned to the Fermilab grounds since the water levels at A.E. Sea and DUSAF pond have been lowered. Photos: Dave Spleha|
Have you noticed the changes over the last couple of years in DUSAF pond and A.E. Sea, near Fermilab’s east entrance? The lakes were lowered to decrease flooding in the Village and to alleviate a number of harmful impacts across many different systems. In addition to contributing to unsafe driving conditions when water floods over the roadway, the high water levels also intensified the pressure and infiltration of water into the sanitary sewers, saturated wooden building support structures and severely tested an outdated storm sewer system made of clay bricks that were never meant to be constantly submerged.
A.E. Sea was designed to be a retention basin with a lower average water height and extra space to hold additional water in the case of a short, heavy storm or flash flood. However, for a number of years, A.E. Sea was purposefully kept at its maximum water height to store water on site, which resulted in A.E. Sea essentially losing all stormwater retention capabilities as originally designed.
The expectation that the eastern lakes were kept high to serve as a backup cooling water supply for the hot summer months is inaccurate. When the lab took steps to limit the release of tritium in 2005, DUSAF pond and A.E. Sea (and the Ferry Creek outlet) were intentionally isolated from the process water supply. And during the few times that the eastern lakes have been used as a backup water supply, it has taken herculean efforts to draw water from these lakes for introduction and use in the cooling water system. These efforts also took place prior to identifying three other higher-priority make-up water supplies: water from the 300-foot-deep Minos tunnel, well number 4, which is on site, and the Fox River.
The lowering of lake levels has brought about ecological benefits, including an abundance of new avian visitors. Nineteen species of shorebirds have graced the newly lowered eastern lakes of Fermilab over the last year, including the willet, a larger shorebird found only a handful of times previously at Fermilab. A true measure of the health of any ecosystem is its diversity, which appears to have been increasing with multiple varieties of sandpipers, dabbling ducks and sparrows visiting the new lakes. One of the rarest of birds found in the Midwest is a white-faced ibis, which had its first confirmed sighting at the lab in April 2013.
It’s exciting to think of what rarity might pop up next in the new, improved eastern lakes of Fermilab.