Project Construction

Kingsley Dam during early stages of construction

Kingsley Dam during early stages of construction
Courtesy Central Nebraska Public Power and Irrigation District

Construction of the Tri-County Project began on March 13, 1936. Kingsley Dam was completed in 1941.

Part 1: Digging & Filling in the Dam

Silent Film of the Construction of the Kingsley Dam
From the Central Nebraska Public Power and Irrigation District film, "Plain Magic"

Part 2: Laying Concrete Blocks

Part 3: Construction Camp

Concrete tetrahedrons, or "jackstones" stockpiled for placement on Kingsley Dam

Concrete tetrahedrons, or "jackstones" stockpiled for placement on Kingsley Dam
Courtesy Central Nebraska Public Power and Irrigation District

At the time of its construction, Kingsley Dam was the second largest hydraulic-fill dam in the world. (Only Ft. Peck Dam in Montana, which remains the largest hydraulic-fill dam in the United States, was larger.) To build Kingsley Dam as a hydraulic-fill dam meant that sand was pumped from the riverbed on both sides of the dam’s centerline by huge electric-powered dredges to form the dam’s sides. A mixture of loess clay and water was pumped into the center of the dam to form its watertight core. More than 26 million cubic yards of earth were moved in building the 3.5-mile-long dam. The dam’s face is covered with millions of tons of rock riprap (protective covering usually for a dam or a shoreline made up of broken rock) in several layers and more than 180,000 “jackstones” (reinforced concrete tetrahedrons), each weighing 800 lbs.

Concrete tetrahedrons and two of the crew

Concrete tetrahedrons and two of the crew
Courtesy Central Nebraska Public Power and Irrigation District

Beginning in 1941, the Central District’s crews fabricated thousands of the 800-pound jackstones to protect against erosion on the face of Kingsley Dam and in other places along Central’s canal system. Although Central no longer makes the jackstones, thousands remain visible on the face of the dam and in stockpile in case they’re needed in the future.

When the dam was finished, Lake McConaughy began to fill with water for irrigation and hydropower operations. The project’s three hydroplants all began to generate electricity in 1941. The project, with more than 500 miles of irrigation canals and laterals taking water to thirsty crops, was completed and in full operation by 1943. The total cost of the project was $43 million. Funding was provided by a $19 million grant and a $24 million loan from the federal government’s Public Works Administration. The Central District made payments on the loan over the next 30 years and repaid the federal government in 1972.

The pipes on trestles on either side of the dam carried the sand-and-gravel slurry that formed the dam’s sides. The pipe down the centerline of the dam deposited the loess clay that forms the watertight core of the dam. The “Morning Glory” spillway can be seen at the far left.