Fishing Lake Cumberland to change after drawdown
FROM RAMPS TO HABITAT, WEAKENED DAM MAKING WAVES
HERALD-LEADER OUTDOORS WRITER
Since Monday's surprise announcement that Lake Cumberland will be drawn down to elevation 680 this year because Wolf Creek Dam is leaking, and at a high risk of failure, there's been a lot of concern about the potential plight of the lake's quality fishery resources.
How will the low water affect striped bass and walleye populations, and trout production at Wolf Creek National Fish Hatchery? What water-quality issues could arise in the fall?
Here's my list of questions and observations, from a fisherman's perspective:
Where will anglers be able to launch at elevation 680?
There are an estimated 60 ramps on the lake and upper river, but most of them will be high and dry. Plans are in the works to lengthen some ramps, but for now, here's a list of seven in the lake that will be usable:
In the lower lake: Halcomb's Landing, off U.S. 127, at Wolf Creek Dam; Jamestown Marina, south of Jamestown, off Ky. 92.
Middle: Conley Bottom, north of Monticello, off Ky. 1275;
In the upper lake: Beaver Creek, northwest of Monticello, off Ky. 92; Cumberland Point, south of Nancy, off Ky. 761; Burnside Island State Park, off U.S. 27 near Burnside; and Lee's Ford, west of Somerset, off Ky. 80.
When the lake bed dries out, a guy with a four-wheel-drive pickup and small boat should have plenty of places to launch, on miles of exposed gravel banks.
"We're going to go back and verify if a ramp can be used, then decide where we need to spend money to fix them (extend into the water)," said Benjy Kinman, director of fisheries for the Kentucky Department of Fish and Wildlife Resources.
What's the short-term impact on fish populations when the volume of a lake is reduced so dramatically, and how is fishing affected?
"This is going to be a 47 percent reduction in volume," Kinman said. "When fish are confined they are more vulnerable to harvest."
Kinman said he believes striped bass fishing could be excellent this spring, with lots of topwater action. Another result of a drawdown is "prey fish species are concentrated and predators eat more. Typically, you see better condition in fish and higher growth rates."
The flip side of the Lake Cumberland drawdown might be increased predation on young-of-the-year game fish species, notably black bass. "With the lake level down there will be a loss of shoreline wood cover," Kinman said. "It will be four or five years down the road, when year classes reach harvestable size, before anglers will notice any declines" in bass numbers.
What's the main risk to striped bass and walleye in the lake?
A wet spring.
"What we need is normal rainfall," Kinman said. "If the lake level has to be continually pulled (lowered) to maintain elevation 680, all the cold water (stored over the winter) could be discharged from the lake."
Kinman said the water exchange occurs in April and May, but the danger of a fish kill comes later -- in the summer and early fall.
Stripers need water no higher than 68 degrees (Fahrenheit), walleye 73 degrees. "They need water in this temperature range, which has the proper levels of dissolved oxygen," said Kinman.
Large adult striped bass and walleye are especially vulnerable because they will stay in water at their preferred temperature, even if it doesn't have the oxygen they need. The result is asphyxiation.
"Striped bass kills are not uncommon," Kinman said. "We had that problem with striped bass in Herrington Lake in the 1970s, and two years ago there was a walleye fish kill in the lower lake (Lake Cumberland)."
Is the drawdown going to affect trout production at the Wolf Creek National Hatchery.
Again, it depends on rainfall, and how much of the cold water stored in the lake is discharged to maintain elevation at 680.
Each year the federal hatchery, just below Wolf Creek Dam, produces about 1 million trout, 800,000 of which are stocked in Kentucky lakes and streams.
Water from the lake is used to rear the trout in concrete raceways. At lake elevation 680, one of the three intakes that feed water to the hatchery won't be operational.
"We have concerns during the summer months," said James Gray, hatchery manager. "The ideal temperature range (for trout) is 50 to 55 degrees. If water temperatures rise into the 60s, that creates problems."
Water from lower levels of the lake will most likely have less dissolved oxygen and that could also influence the number of trout that can be raised.
Gray said he can't predict to what extent production could be affected. "There are a lot of variables, but there's potential for a big impact."
How will water levels and fishing conditions in the tailwaters (Cumberland River) be affected by the lake's severe drawdown?
"There will be a normal fluctuation (in river level) based on rainfall," Kinman said.
The danger to trout populations will come during the dry months of the year, at low flow.
To ensure proper water temperature and flow, Kinman said a minimum discharge of 500 to 600 cubic feet per second of water is needed. "This will prevent (large expanses of) exposed gravel, which over time could be harmful to aquatic insect life."
He said the Army Corps of Engineers "is willing to work with us on this. They understand the dangers to trout populations in the tailwaters." And the oxygenation of water discharged into the tailwaters isn't a problem. "The coldest water from the bottom of the lake can be run through the sluice gates and oxygenated as it sprays up over the concrete apron at the base of the dam."
Will water temperatures and dissolved oxygen levels be monitored?
"Yes, after July," Kinman said. August through October are the most critical months for a major fish kill.
Will plans for stocking striped bass be altered during the drawdown?
Yes, with the numbers stocked adjusted down for the smaller size of the lake, 35,000 surface acres at elevation 680. "In 2007 we'll stock 7.5 fish per surface acre of water."
No adjustment in walleye numbers is anticipated. "Walleye are stocked at a fairly low rate."
What will be the impact on smallmouth bass reproduction and the annual spring walleye run?
"There will be more riffle areas in the upper lake created by the drawdown, but it's uncertain if that could enhance the walleye run or give smallmouth bass more areas to spawn," Kinman said.
What long-term positives could come out of a prolonged drawdown?
"Drawdowns create the new lake effect," Kinman said.
Banks grow up in grasses, shrubs and trees, creating cover for fish when lake levels return to normal. Large spawns result and fish populations expand.
"If the lake is maintained at elevation 680 past this fall, we are planning a major habitat improvement project to put fish attractors on mud flats," Kinman said.
Low water also allows anglers to survey the bottom, and gives them an opportunity to get involved in removing trash from exposed banks.
What impact could fewer recreational boaters have on the fishing experience?
From Memorial Day to Labor Day the lake is overrun with pleasure boaters and personal watercraft. If a prolonged drawdown translates into a drop in recreational boating, this will directly benefit fishing. There will be less wave action, fewer muddied banks, and more peace and quiet for anglers.
That would be a good thing.