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Woods Reservoir completed 70 years ago this month

  • Published
  • By Bradley Hicks
  • AEDC Public Affairs

Before the first foundation was poured or stone set, a site for the proposed Air Engineering Development Center would have to be chosen that could meet three primary needs.

Along with finding a suitable tract of land for the center and a place where large amounts of electrical power were available, planners would need to find a location with access to copious amounts of water. It was determined early on that center operations would require millions of gallons of cooling water.

Camp Forrest, a former Army training area, hospital and prisoner of war camp near Tullahoma, was selected for the site of the AEDC in April 1948. The center soon became known as the Arnold Engineering Development Center and eventually the Arnold Engineering Development Complex headquarters. And it wasn’t long after this site was picked that work to supply the necessary water was finished.

The construction of the Elk River Dam was completed 70 years ago this month. The purpose of this project was the creation of what came to be called Woods Reservoir, a 4,000-acre repository that has continued to provide AEDC test facilities at Arnold Air Force Base with cooling water and the public with a spot for outdoor recreation in the decades since it was formed. 

In October 1949, President Harry S. Truman signed the Unitary Wind Tunnel Plan Act and the Air Engineering Development Center Act of 1949. These bills authorized a unitary plan for the construction of transonic and supersonic wind tunnels and authorized the $100 million appropriated by Congress for the construction of the AEDC.

The Army Corps of Engineers was tasked with overseeing part of the AEDC design and all of its construction. The Tullahoma District of the Army Corps of Engineers was established in November 1949 for this purpose.

Soon after this district was formed, the dam became a major topic of focus. In January 1950, the first construction directive for the AEDC was issued by the Headquarters of the Air Force to the Army Corps of Engineers chief of engineers. This charge covered preliminary investigation and design of the dam and preliminaries to land acquisition, as well as administrative expenses for the recently-established Tullahoma District.

Planners recognized that by damming the Elk River, a 4,000-acre reservoir with a capacity of 26 billion gallons could be created.

Several sites along the Elk River were studied for the site of the earth fill and concrete gravity dam, with a point on the waterway about 5 miles from the test center chosen.

Prior to the official selection of this site, St. Louis, Missouri-based engineering firm Sverdrup & Parcel Inc. issued a report on requirements for the Elk River reservoir. According to this study, the cost of the reservoir, excluding the land, was estimated to be nearly $3.6 million. It was recommended that the reservoir design criteria be determined by the Army Corps of Engineers.

According to this report, the amount of water required annually for AEDC operations would be more than 22.4 billion gallons. Of this, the vast majority – nearly 21 billion gallons – would serve as cooling water for the test facilities. The remainder would be used for air conditioning, sanitary water and fire protection.

In early March 1950, less than five months after Truman signed the bills that cleared the way for its establishment, the Secretary of Defense approved the construction of the AEDC. The process began quickly. The first contract for center construction – the manufacture of Engine Test Facility cranes – was awarded by late March 1950.

Work on the Elk River Dam would begin soon after. That June, the Army Corps of Engineers awarded a contract to build a dam over the river. By that December, the dam and reservoir undertaking was estimated to be 6% complete.

The additional land required for construction of the reservoir was acquired in early January 1951. At that time, the Headquarters of the Air Force requested that the Army Corps of Engineering chief of engineers proceed with the purchase of 6,650 acres needed for the waterbody. This was in addition to the initial 633 acres acquired in September 1950 that were to be used for the dam and part of the reservoir.

A diversion channel for the Elk River Dam was completed in late January 1951, and the river was diverted into it by means of an earth coffer dam.

By July 1951, the construction of the dam and reservoir was approximately 30% complete and was deemed to be well ahead of schedule. Work would continue to roll along at a good pace. By late December 1951, the project was 83% complete compared to the scheduled progress by this point of 53%.

The impoundment of water in the reservoir began on May 1, 1952, and construction of the Elk River Dam was completed that September. The daily cooling water requirement for the test facilities was described at the time as “an amount more than the daily requirement for a city the size of Washington, D.C.”

According to a May 1953 Tullahoma District of the Army Corps of Engineers report that detailed the agency’s efforts in the design and construction of AEDC, the finished dam was 90 feet high at the center valley section and 3,000 feet long. The spillway, with a design capacity of 104,000 cubic feet per second, was 170 feet long and controlled by three 25- by 50-foot tainter gates.

The concrete non-overflow section was 360 feet long.

The area of the reservoir was just shy of 4,000 acres with a storage capacity of 80,600 acre-feet at normal pool, according to the same report.

When filled, the lake formed behind the dam would measure about 12 miles long with a shoreline of approximately 75 miles.

“The primary purpose of the Elk River Dam and Reservoir is for the storage of water to be used for cooling purposes required by the test facilities, although it will serve to reduce floods slightly in the lower reaches of the Elk River basin,” the Tullahoma District report stated.

A Primary Pumping Plant was constructed on the north side of the reservoir upstream of the dam. This plant provided an initial capacity of 100,000 gallons per minute. Eight-thousand horsepower were required to operate its four 25,000-gallon per minute vertical pumps.

The plant was needed to pump water from the Elk River reservoir to a secondary reservoir located within the AEDC test area. Transmission of the water from the Elk River reservoir to the one located at the center was provided by a high-pressure steel pipeline measuring 5 feet in diameter and approximately 4 miles long.

The secondary reservoir located within the AEDC mission area had an initial capacity of 13 million gallons. That amount was increased to 58 million in 1961 following the completion of a 45-million-gallon expansion project. It would be the job of a Secondary Pumping Station located within the main AEDC area to pull water from this secondary reservoir and transmit it to the test facilities.

“As the capacity requirements increase, provisions have been made for additional pump capacity and pipelines,” the Tullahoma District document stated.

Features were implemented that allowed cooling water to be returned to the Elk River reservoir once it had served its purposes in AEDC test areas.

“The temperature of the cooling water, after use in the testing facilities, is not expected to exceed 135˚F,” the Tullahoma District report stated. “A gravity outfall, or discharge ditch of adequate design and capacity, built for the cooling water to return from the center to Rollins Creek was constructed. From thence, the discharge water will meander down the natural channel of this creek and return to an arm of the Elk River reservoir immediately above the dam.”

A service road leading from the AEDC test area to the Primary Pumping Plant and from the plant to the Elk River Dam was constructed. The only road relocations required were the county roads and bridges that would be inundated by the filling of the reservoir.

The only significant road relocation resulting from the reservoir project required the construction of approximately 1-mile embankment and a four-span continuous steel bridge with concrete deck at Morris Ferry.

In June 1953, the Elk River reservoir was named Woods Reservoir in honor of the late Col. Lebbeus B. Woods. A dedication ceremony attended by Woods’ wife and son was held the following month at the reservoir. Woods was one of the first two Air Force officers to arrive at AEDC for the center project. He served at AEDC until February 1952, when he was given one of the top posts within the then-active Air Materiel Command. While at AEDC, Woods served as the deputy chief of staff for materiel and was responsible for much of the early organizing, staffing and master planning for the center project.

Woods Reservoir opened for public fishing and recreation on May 30, 1953. The lake quickly attracted swimmers and skiers, and the beach areas around it served as ideal locales for AEDC picnics, beauty pageants and get-togethers with family. Still considered a haven for anglers, Woods Reservoir is home to several types of bass, crappie and catfish. There are several boat access points and public fishing piers around the lake.