with the water rights held by these hydroelectric plants, it was necessary for the Government to purchase the plants, and provisions have been made to replace the power previously furnished by these hydroelectric plants. Diesel installations at Wauneta not only serve power to the Wauneta area, but also supply the load formerly served by the Oliver Brothers' plant. The REA now supplies power to consumers who had received power previously from the Grosbach-Williams and Krotter Powerplants.

7. Industrial Development. Industrial production within Hitchcock, Red Willow, Furnas, and Harlan Counties is limited, with a few exceptions, to processing locally produced materials for local consumption. The extensive development of local industry has been prevented by lack of cheap fuel and power, distance from large market centers, and absence of a variety of natural resources. Grain elevators are common, being readily accessible by railroad or truck. Most of the elevators do custom grinding for local customers. Sand pits are operated whenever there is local demand.

8. Transportation Facilities. The transportation facilities are ample for the needs, though somewhat taxed during harvest season. The Chicago, Burlington, and Quincy Railroad traverses the division. A branch line extends from Culbertson through Enders to Imperial, Nebr. Because of cheaper construction and better grades, the rail lines generally are confined to stream valleys. The area is also served by an expanding motor transportation system. Paved transcontinental United States Highways No. 6, 34, 83, and 283 traverse the area. Improved State highways and county roads supplement the United States highway system, and all communities are readily accessible. Besides locally owned and operated trucking firms which transport petroleum products, livestock, grain, and other short-haul goods, the area is served by large transcontinental truck lines. Bus lines operate throughout the area. Nebraska State Highway No. 61 passes through Enders, so that no problems in transportation and accessibility to the construction site were involved.

B. Project Development

9. Feasibility Investigations. The potentialities of developing the water and land resources of the area were recognized for a long time by the inhabitants. Development of privately owned irrigation facilities in Frenchman Valley began about 1890. Lack of moisture induced many enterprising farmers to attempt the use of stream waters for irrigation. Distribution systems that successfully transported the water to irrigable lands were constructed with slips and hand labor. Irrigators purchased water only as a last resort to save crops. By 1912, all important irrigation ditches were in operation. All systems diverted water from the streams by gravity flow. Pumping installations were installed through the period from 1912 to 1921. The primary factor limiting full development of the systems was always the lack of storage facilities.

The building of Enders Dam was preceded by numerous feasibility investigations. On many occasions, local interests sponsored private investigations; and as early as 1912, consulting engineers studied the possibilities of providing storage on division streams. The Corps of Engineers, Department of the Army, and private enterprises expressed renewed interest in the development of the Republican River basin about 1933. Droughts and the ravaging flood of 1935 aroused citizens of the Republican River basin, who through concerted efforts appealed to the Government for assistance. Federal agencies responded by making several investigations and preparing reports relative to coping with these exigencies.

The Bureau of Reclamation received authority to make preliminary examinations of the Republican River basin in Public Documents 493 and 738, 74th Congress, 2nd Session, 1936. The Reclamation Project Act of 1939 (53 Stat. 1187) authorized investigation for the full conservation, control, and use of the water resources of the Missouri River basin, of which the Frenchman-Cambridge area is an integral part. About the same time (1940-43), the Corps of Engineers proposed development of the Enders site and the Bureau proposed development of the Harvey site on Frenchman Creek about 6 miles upstream. The Harvey plan included a reservoir with a capacity of 35,000 acre-feet as compared with a 44,000 acre-feet dual-purpose reservoir in the

Enders plan. Both sites would serve all potential irrigation developments in Frenchman Valley.

10. Cooperation with Other Organizations. - Many local, county, State and Federal agencies, together with municipalities, corporations, associations, businessmen, and farmers have contributed to and have aided materially in making investigations and assembling data required for the development of the Frenchman-Cambridge Division. A list of some of these organizations follows:

11. Authorization. - The basic plan of the Frenchman-Cambridge division, including Enders Dam, was authorized by the Flood Control Act of 1944 (58 Stat. 887). The act approved the comprehensive plan for developing the Missouri River basin set forth by the Bureau of Reclamation in Senate Document 191 and by the Corps of Engineers in House Document 475, as revised and coordinated by the Senate Document 247 (78th Congress, 2nd Session). The initial stage of development recommended by the documents received authorization at the same time. Included in that initial construction program are the major structures and irrigation systems for substantially all lands to be developed in the division.

The plan in Senate Document 191 proposed the construction of Culbertson reservoir on the Republican River, Harvey reservoir on Frenchman Creek, and Medicine Creek reservoir on Medicine Creek. These three reservoirs, constituting the storage facilities of what was then known as the Frenchman-Cambridge project, would regulate the flows of the Republican River and its two principal tributaries to permit irrigation of 57,925 acres. Also proposed was the Wells unit, called "Pumping" in the initial construction program, which would supply from underground sources 23,500 acres of irrigable land scattered throughout the Republican Valley; of this amount, approximately 11,300 acres are located within the division boundaries. Thus, the portion of the Wells unit combined with that of the Frenchman-Cambridge project results in a total of 69,225 acres authorized for the division as shown on figure 3, which area is in the most part included in the modified plan of development also shown on figure 3.

The reconciliation of the Bureau of Reclamation plan and the Corps of Engineers plan in Senate Document 247 introduced several modifications. On Frenchman Creek, the Enders Reservoir in House Document 475 was substituted for the Harvey Reservoir in Senate Document 191 because the Enders Reservoir could be built to a greater capacity and would provide more storage for irrigation and flood control. Red Willow Reservoir, included in House Document 475, was not deleted and thus became an added feature. Culbertson Reservoir was not affected; however, subsequent investigations relocated the

bra

dam site upstream, and the dam was renamed Trenton Dam with the reservoir being called Swanson Lake.

12. Division Plan. - Enders Dam is a feature of the Frenchman-Cambridge division plan. The development of the plan includes the construction of storage facilities and irrigation works. The construction of the four multiple-purpose dams on the Republican River and its principal tributaries will provide sufficient storage of streamflows to achieve the planned development. The dams constructed by the Bureau of Reclamation are Enders Dam on Frenchman Creek, Trenton Dam on the Republican River, and Medicine Creek Dam on Medicine Creek.

Reservoirs will be operated to obtain maximum benefits not only for the Frenchman-Cambridge division but also for the entire basin. To effect complete utilization of the available water supply, it is proposed to store all water that can be stored practicably in upstream reservoirs. This will integrate operation in serving the irrigation units in the division as well as providing for releases to downstream development, namely the Bostwick division, as required for equitable distribution. Benefits will result from provisions of the plan which allow for the adjustment of water shortages so that to some extent basin-wide shortages will be reduced and the severity of shortages for any one area will be minimized.

Storage of water in reservoirs of the Frenchman-Cambridge division will provide for the irrigation of 68,570 acres. Irrigation works will supply 67,680 acres; the remaining 890 acres will receive storage benefits only. The 890 acres consist of 710 acres irrigated by stream pumps on Frenchman Creek and 180 acres served by the McLain canal on Stinking Water Creek. Severe shortages experienced by these lands due to senior water rights of lands in the Frenchman unit will be mitigated by the provision of adequate storage in Enders Reservoir.

For purposes of economic and efficient development, project lands for which irrigation systems have been or will be constructed are divided into four units: Frenchman, Meeker-Driftwood, Red Willow, and Cambridge. These units are shown on figure 3. Frenchman unit lies along Frenchman Creek and the north side of the Republican River and extends from the confluence of Stinking Water and Frenchman Creeks to the outskirts of McCook, Nebr. The existing Culbertson Diversion Dam near Palisade will be rehabilitated to divert releases from Enders Reservoir into approximately 79 miles of canals serving 22,020 acres. Supplemental water releases for Red Willow and Cambridge units are provided. Culbertson Canal and its extensions will supply lands on the north side of Frenchman Creek, and the Beverly-Riverside Canal will carry irrigation water to lands on the south side. The existing Riverside Diversion Dam will be abandoned. Most of the irrigation system in operation at the start of construction of Enders Dam has been or will be reconstructed.

13. District Organizations. There are two irrigation district organizations in the Frenchman-Cambridge division: the Frenchman Valley irrigation district and the Frenchman-Cambridge irrigation district. The Frenchman Valley irrigation district originally included 9,450 acres, and the Frenchman-Cambridge irrigation district included 36,990 acres. The plan of development proposed the enlargement of the existing districts to include a total of 67,680 acres. The 890 acres to receive the storage benefit only were to be administered under a Warren Act contract. After reorganization, the Frenchman Valley irrigation district includes all of the 22,020 acres in the Frenchman unit, and the Frenchman-Cambridge irrigation district includes the combined area of 45,660 acres in the Meeker-Driftwood, Red Willow, and Cambridge units.

8

CHAPTER II--INVESTIGATIONS

A. Geology

14. Regional Geology. In this region, the overburden of the broad Frenchman River valley is underlain by the Ogallala formation of Pliocene Age which in turn is underlain by the Pierre shale about 175 feet below the valley floor. The Ogallala formation in this region is composed of fine to coarse sand, some gravel, calcareous silt, silty sands, silts, and clays. Various degrees of calcareous cementation occur, resulting in lenses of very loose unconsolidated to very firm compact materials at irregular intervals. The Ogallala beds lie almost horizontal; and structural irregularities, such as faulting, have not been observed in the area. Generally, the ground water was in the Ogallala beds and was tributary to the reservoir prior to construction. Since the completion of the dam, undoubtedly some of the ground-water tables are tributary from the reservoir because of seepage along certain areas.

The overburden consists of alluvial materials on the valley floor and of reworked loess and slope wash materials on the valley sides. The alluvial materials are a mixture of fine sand and small pea gravel with a high percentage of chalk particles. The reworked loess ranges from sandy to clayey loam of low to moderate density. The slope wash material is a mixture of loess and Ogallala talus resulting from colluvial action.

15. Foundation Explorations. - Foundation explorations were carried on before, during, and after construction. Preliminary exploration of foundation conditions at the site of Enders Dam and dike were carried out during the period from January to October 1945. Because preliminary exploration and testing, for which there was insufficient time and upon which the foundation design was based, did not delineate adequately the foundation conditions, additional exploration was necessary during the preconstruction, construction, and postconstruction periods. Foundation conditions disclosed by additional drilling and testing resulted in changes in the foundation design. The extent of these exploration programs is indicated in the following tabulation, which lists the number and type of holes, shafts, and trenches.

a/ 58 in spillway and 21 in outlet works.

4g/

5/ 24-inch, outlet-works holes extended by diamond drill.
C/ Profiles developed from required excavation also used.
d/ Drilled primarily as ground water observation holes.
e/ Combination drive and modified drill.