$100 million-$200 million repair project planned at Kingsley Dam on Lake McConaughy (2024)

LAKE McCONAUGHY — A centerpiece of the multifaceted Central Nebraska Public Power and Irrigation District will be undergoing a $100 million-$200 million repair project, possibly within the next five years.

Nearly 100 years after Nebraska’s largest hydropower and irrigation project was organized in 1933, Kingsley Dam, which created Lake McConaughy on the North Platte River north of Ogallala, will get a new face.

“It took 80 years to determine that its facing was inadequate,” General Manager Devin Brundage said during a CNPPID system tour Monday from the Holdrege headquarters to Lake McConaughy for Tri-Basin Natural Resources District staff, board members and other invitees.

Central’s system delivers water stored in Lake McConaughy to its primary irrigation service area in Gosper, Phelps and Kearney counties, and has small hydropower plants near Brady and Johnson Lake. Those and most other project elements were constructed from 1935-1942.

A framed “Tri-County Project” invitation displayed at the Gothenburg Control Center encouraged the recipient to attend the “dedication of the George P. Kingsley Dam and McConaughy Lake at the dam site on July 22, 1941.”

Kingsley is an earthen dam that is 3.1 miles long and 163 feet high. Behind it is the 22-mile-long Lake McConaughy, which covers 30,500 surface acres and has 1.7 million acre-feet of storage.

CNPPID Natural Resources and Compliance Manager Mike Drain pointed to the rock-protected Kingsley Dam face during Monday’s tour stop at the lake and said investigations of dam damage occurring during the 2021-22 water storage season determined that the its current riprap erosion protection is inadequate.

It’s a systemic problem resulting from a lack of the necessary filter system behind the rocks to prevent sands and gravels from migrating out of the dam and into the lake, Drain explained.

CNPPID staff are working with hydraulic engineers and dam design consultants to evaluate a variety of riprap and non-riprap alternatives. State officials and the Federal Energy Regulatory Commission, which licenses CNPPID’s hydroelectric facilities, also will be involved.

“Our goal, if we do it right, is to not impact anything in district operations,” Brundage said. “... We’re still identifying what the right solution is, and the funding. The number one consideration is that this dam is safe and that it’s fixed right.”

Different solutions have different costs, which is why the current estimate is $100 million-$200 million.

Drain said one of the most common questions he’s asked, especially by folks in the Ogallala area, is how the dam project might affect traffic on the highway across the dam. It’s too early to know the answer.

He told Monday’s tour group that the work will be done along nearly the full 3.1-mile length of the dam, with the area replaced will equal to more than 30 football fields.

All of the rock will be removed and something new will be below it. “We don’t know yet what that something new will be,” Drain said.

The tentative timeline is to model alternatives through 2026, have a final design and select a contractor in 2027, and do construction from 2027-2029.

At 22 miles, Lake McConaughy may be the longest straight water distance to any U.S. dam. That, plus the wind direction in Western Nebraska, results in a lot of wave wear and tear on Kingsley Dam.

“The waves generated here are more like you’d see in a coastal area than at an inland lake,” Drain said.

His tour handout lists cost categories for Kingsley Dam and Lake McConaughy: operational expenses; recent and ongoing large project expenditures, such as painting the morning glory and outlet tower near the dam every 20 years or so at a most recent cost of $2 million; and future projects that include renewing the FERC license.

The last item on the future list is the Kingsley Dam refacing. “That’s the big one. The one that seems to make everything else seem minor in comparison,” Drain said.

He reminded the tour group that operating and maintenance costs for Kingsley Dam and Lake McConaughy must come from other revenue sources. FERC license regulations forbid CNPPID from generating income from the lake’s recreational uses.

So those costs are covered primarily by irrigation customers, special water agreements, Supply Canal cabin leases and Supply Canal hydropower generation from the Jeffrey, Johnson 1 and Johnson 2 plants that each produce approximately 22 megawatts of electricity.

Brundage said that depending on water supplies, those three plants can generate revenues of $8 million to $15 million per year in sales. That energy is sold to buyers under negotiated contracts for a set number of years.

However, all power from the 50-megawatt capacity Kingsley Hydro built in the early 1980s is sold to the Nebraska Public Power District for approximately $200,000 a year under a “life of the hydro” contract.

Brundage said the CNPPID board and staff try to save for big maintenance and replacement costs so work can be done without debt, but the huge dam refacing project may be funded with bonds.