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FFMP - The Pros And The Cons.

Posted on July 31 2023

 It's Sunday afternoon and I'm home waiting for cocktail hour with my wife. There was a dearth of questions this week so the page will be spent discussing the long term effects of the FFMP.

The FFMP (Flexible Flow Management Plan) is the best flow program I've seen during my 35 years fishing the Delaware River System. The increased flows have resulted in a major increase in both the fish carrying capacity of  the WB and the BR and the number of drift boats floating them. Keeping the water temp below 75 at Lordville provides a large thermal refuge for the down river fish which in turn increases the number of fish all the way down to Callicoon during the "big bug hatches".  Elimination of the dewatering of large portions of the stream bed in the upper WB caused by the former low flows has resulted in a major increase in caddis hatches in the "Sulfur Zone". These are the basic plusses that I have observed.

As with most everything in life - if there are plusses there are also minuses. I've given some thought to things I've observed over the past few years that I believe can be considered negatives when talking about the FFMP releases. (Here's where he goes on a rant about the number of drift boats). No, drift boat fishing has evolved with an acceptable pattern of behavior for both the drifters and waders that most abide by and can live with.

The negative I am talking about is the impact the additional releases have had on the insect life in the upper WB and the fish that reside therein. I have no formal education in entomology  or marine biology and would welcome one educated in either field to set me straight, but here are my thoughts and observations.

1 - Tailwaters are known for prolific hatches of a limited number of different bugs (think olives and sulfurs on the Delaware). 

2- When I started fishing the Delaware and for many years thereafter there was a full compliment of may fly hatches at least up to Oquaga with many hatching up to Cold Springs Brook.

3- As flows have increased (each lowering the water temperature a further distance down river) the upriver hatches of the "non- tailwater bugs" have decreased and in some cases virtually disappeared. 

4- The hatching of Tricos, Green Drakes, and Ephorons (all warm water loving flies) have always been limited to the lower reaches of both the UEB and the WB and the BR. With the increased flow of cold release water, other species have also disappeared from the colder water in the upper WB. I use to see good hatches of Gray Foxes, March Browns and Isos well above Deposit. The Hendricksons which are both hardy and prolific have continued to hatch up river but the hatch starts later and runs later in Deposit than it use to (cold water slows the maturation of the nymphs?). Which brings me to my comment about Green Drakes hatching at the Red Barn (aka pasture pool), Every summer fishermen see a few green drakes on the water there. Their maturation is a good two months behind their freestone river friends and I think they are going to find slim pickings when looking for a mate. 

So, assuming that my observations are accurate and meaningful what does this mean for the river system?

1 -  It has been my observation that fish are growing slower in the upper WB of the Delaware in recent years. Is this because the cold water slows their metabolism or because, with the absence of the aforementioned bugs, there's just not enough food for them to grow as fast, or perhaps a combination of both?

2 - There is now, a seemingly ever increasing gap in the fly hatching activity in the upper WB fishery after the Hendricksons and caddis and before the summer sulfurs (Dortheas). The Invaria (spring sulfurs), long a gap filler, seem to be less and less numerous up river every year, quite likely they are not a true tail water sulfur and are also negatively affected by the lower water temps.

It's not my intention here to champion either bigger or smaller releases. I just want to show that there are consequences to whatever action is taken (some of which evolve over a period of time. come as a surprise and are unintended). Would welcome observations from other fishermen as well as input of a scientific nature from either entomologists or marine biologists. 


  • Joseph Anscher: August 01, 2023

    No doubt that each insect population has evolved to some very specific environmental triggers effecting their life cycle. Considering that temperature and even flow has an effect on the hatching cycle, the FFMP and the release of cold water would certainly have an effect. It may favor some, including trout. But it may also negatively affect some other bugs. Either way, more consistent flows, I believe has great benefit. And I quite frankly believe, that when all is said and done, there isn’t much we can do to increase the intensity of the hatches. But, I’ll leave that to the biologists to figure out.

  • Andrew : July 31, 2023

    Your observations are spot on. Much like our climate and the wild variations ever increasing so goes the stream. Inconsistency I believe the word is. Also spikes of abnormalities.

  • Dennis: July 31, 2023

    I am unqualified to speak to any of the posts. Thank you for the education!!!!

  • Ed Smith: July 31, 2023

    Angler119 Thank you for your observations about the FFMP. I have relatively little experience on the upper WB but your comments are in line with what I know of other tailwaters. It seems that the FFMP is an overall positive for the Delaware system. As far as the bugs are concerned we will just have to adjust.Thanks again. Ed Smith

  • chris: July 31, 2023

    Yep, water temp does indeed influence maturation of nymphs. Assuming the water is in an acceptable band, it takes a certain number of “degree days” for a nymph to develop.

  • Jack: July 31, 2023

    Angler 119
    Your observations are in rough agreement with my limited data base.
    My early work on the FFMP (followed by the significant work by Peter Kolasar at Columbia U.) was an attempt to convince the powers that be (primarily the NYC DEP) that in most years there was much more water available to release than was being released. The event that I believe finally led to an agreement was the major flood of 2006 (remember the cabins from the WBA washing down the river?) and the damage to the communities that it caused.
    Your post reminded me of the time many years ago I was fishing one of the “Gold Medal” trout streams in Colorado. It was a tailwater, and the water in mid-July was high 40s. I spoke to a fish biologist who said they had done radio-collar tracking on the trout in this stream, and the growth was Way below average. I asked why it was still considered a gold medal stream, and the response was : Politics.

  • Dennis 2: July 31, 2023

    Your obervation that the hatches. Are evolving over several years matches what I heard from a western fisheries biologist who claimed it takes a hundred years for a the hatches to fully evolve after a dam creates a tailwater fishery.

  • HydeLowRider: July 31, 2023

    “The Invaria (spring sulfurs), long a gap filler, seem to be less and less numerous up river every year, quite likely they are not a true tail water sulfur and are also negatively affected by the lower water temps.” Very similar pattern with tailwater fishery – Gunpowder River – that I have noticed since early 80’s. Coincidence? I think not.. HLR

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