Tweaking the FFMP to save the trout fishery

The Flexible Flow Management Plan (FFMP) is a great attempt at managing the reservoirs without the impossible task of meeting some temperature target or flow target at great distances downstream of the reservoirs. Unfortunately, it contains a fatal flaw, which if not corrected, will undoubtedly result in the continued decline in the lower West Branch and Main Stem trout fishery: the lack of proper mandated releases from Cannonsville when the total system is in L2. [L2 is the second highest of the five degrees of reservoir fullness that determine the quantity of releases under the FFMP].

The current FFMP would mandate a drop from releases as high as 1,500 cfs to 260 cfs, even when Cannonsville is full in mid-summer. The nationally famous wild rainbow trout fishery in the Main Stem of the Delaware was created solely by releases from Cannonsville to satisfy the Montague target. Over the years, each subsequent modification to flow or release strategy for the Cannonsville Reservoir has whittled away at the intensity and frequency of the Montague releases, to the point where the Main Stem rainbow trout fishery has been mostly replaced by a lower density brown trout fishery, and insect hatches are less intense and more unpredictable.

Under previous release protocols, a “thermal bank” existed that, from time to time, compensated during periods when there were no Montague releases. The current FFMP no longer contains any habitat banks or thermal targets. Instead, it was understood (by many of the biologists involved with the concept of doing away with these onerous “banks”) that releases from the reservoirs tied to the storage in the reservoir would not only do away with any need for thermal releases, but would eliminate the so called yo-yo releases, which are so detrimental to the entire coldwater ecosystem formed by the construction of these reservoirs. And fortunately, the releases in the FFMP for Pepacton and Neversink are an improvement over previous strategies.

Cannonsville, however, is another matter. Under the existing FFMP release schedule, there would be an undetermined duration and frequency of releases from Cannonsville at 260 cfs during the summer when the system is at L2. Even if Cannonsville were almost spilling, the current strategy would mandate only that amount. To reduce releases to that amount would have devastating effects on the West Branch and Main Stem trout fishery and their aquatic life, including the nationally endangered dwarf wedge mussel.

Fortunately, a simple solution is available to change a completely unacceptable flow program to one that would undoubtedly not only protect the remaining trout fishery but greatly improve it, most likely to a condition better than ever. All that is needed is to add three or more release levels from Cannonsville when the total reservoir system is in condition L2, with releases from Cannonsville tied to the storage in Cannonsville alone. It should be possible to make such a slight modification to the existing FFMP with virtually undetectable effects on any other users, New York City or downstream users.

The concept is simple. As Cannonsville is drawn down, releases from it decrease proportionally, instead of a steep drop to what are virtually drought conditions for the coldwater ecosystem. Then, if the reservoir refills as a result of a rain event, Cannonsville releases are accordingly increased. Such a release protocol not only would minimize the yo-yo effect, but lessen the impact of the assumption that the “drought of record starts tomorrow,” when it most patently is not occurring.

(Pennsylvania Fish and Boat Commission Commissioner Robert Bachman was appointed by Governor Rendell in April of this year. He earned his PhD from Penn State doing a four-year behavioral study of free-ranging wild and hatchery trout in a Pennsylvania stream in 1982. He currently serves on the Sub-Committee on Ecological Flows of the Delaware River Basin Commission.)