The dam system in central Wyoming has had a dramatic impact on our way of life

By Bill Andrews

In the early 1900s, farmers along the Central North Platte only cultivated approximately 5,000 acres annually; in a good year, they might have planted 8,000 acres. In 1902, what has become the Bureau of Reclamation was signed into existence and a year later, the new agency authorized the Sweetwater Project and construction of Pathfinder Dam on the North Platte, in what has become known as the Platte River Basin.

The first fight over the dams in Wyoming came from the farmers along the North Platte. They saw the need for water. But they also worried that a dam on the river was a means to steal their water rights and increase control by the Federal Government. The idea of irrigation was not receptive as a means of watering the land initially, but farmers came to understand, when they no longer relied solely on rainfall, that agricultural production increases were possible.

The dam system

After the initial arguments, planning was completed and the first (Pathfinder) of seven dams on the North Platte was built to increase water reclamation resources and irrigation of Central Wyoming acreage to Nebraska. Construction began in 1905, and ended in 1909. Since Pathfinder Dam holds an astounding 331 billion gallons of water, it was believed at the time that it would satisfy all Central Wyoming's and Nebraska's agricultural water needs for years to come.

Unfortunately, the devil was in the details politics and deceit were at work. Although promises were made to the State of Wyoming regarding how much land could be irrigated, most of the reclaimed water irrigation occurred in Nebraska. This was due to a dam bypass built during construction, that for years fed water, uncontrolled into the river below the dam.

In 1912, the second fight broke out, and has been going on ever since. With water bypassing the Pathfinder directly to Nebraska, the Wyoming State Engineer complained that too much water was going to Nebraska, and not enough was being used to irrigate Wyoming farmland. A proposal was made to build a second dam (Seminoe) upstream from Pathfinder to create a new water reclamation point, that allows control of the amount of water being used in irrigating Central Wyoming. Due to politics and funding, 25 years passed and Seminoe dam wasn't completed until 1939.

During this time, the continued bypass of water at Pathfinder to Nebraska prompted the installation of two water flow control tunnels and valves completed in 1927. Two thousand miles of irrigation canals fed 220,000 acres of Wyoming and Nebraska farmland by the 1920s,

Finally, Seminoe

Water is power, not just the political jockeying that has characterized its manipulation and use for years across the Western states, but real unbridled power cascading over spillways during high water, or when directed to create electricity. Seminoe dam was finally built in 1939 with two goals in mind. One: for the first time, Wyoming could completely control the amount of water being fed to the Pathfinder, enroute downriver to Nebraska. Two: the dam offered the additional benefit of hydroelectric generators to provide electric power year around.

Electricity has become essential to the infrastructure of the Wyoming, and this has been one of the major focuses of the North Platte dam projects. Not only does the water bring life to the arid lands of Wyoming, but it powers the industries that make Wyoming a natural resource powerhouse. Additionally, due to new irrigation canals and feed tunnels constructed from the dam, Central Wyoming significantly increased its irrigable land by an additional 22,000 acres downstream.

The high cost of human lives

In a concerted effort to bring power to the state and more water to much of the arid lands of Central Wyoming, dam construction continued along the North Platte. Diversion dams create reservoirs for irrigation that feed the water-hungry farms that cropped up further downstream northeast from Seminoe. One such example is Kortes 20 Dam, situated between Seminoe and Pathfinder, and completed in 1951. Primarily built as a hydroelectric dam, it is the smallest reservoir in the system. Construction of the Kortes required a fight, though this fight was not with politicians or shady railroad barons, but with Mother Nature. Hard winters in 1948 and 1949 almost completely shut down construction, delaying the schedule almost a year. Furthermore, natural rock formations along the canyon walls, supporting the dam began to fracture, allowing large sections of the wall to collapse into the dam's construction area and slow construction until they were removed. After all the delays, what started out as a $4.7 million dollar project resulted in an even higher cost of human lives. Before it was finished, 117 people died on the dam site, one of the highest human cost to build any dam in the United States. (This includes the dangers encountered during the Hoover Dam build, which is im- mensely larger.) Benefits to the area were significant though: power, water, and recreation were huge attractions. Al Gettings, a Wyoming Game and Fish specialist who works at the state fisheries said, "Local fisheries provide brown trout and assorted other varieties of fish for annual stocking of the reservoirs." He points immediately downstream from the dam to a world-class fishing area known as Miracle Mile. According to Gettings, "Rainbow trout are stocked in the Mile annually contributing to the fantastic fishing you experience in the area.

Recreational benefits

Alcova Resevoir is one of the main water recreational attractions in Wyoming. Centrally located with multiple camping and designated RV areas, Alcova caters to the water lover throughout the summer. Year around fishing is popular, especially ice fishing in winter months. The resevoir has a marina and restaurant that caters to locals and visitors. If you are there over Fourth of July weekend, you can take in a memorable over-the-water fireworks display. Overlook homes abound, and real estate is available with great views. The reservoir also has the largest presence of Wyoming Game and Fish officers and deputy sheriffs in Wyoming patrolling it during the summer months.

Despite these many benefactors, Alcova Dam does not receive the notoriety of the three dams upriver from it. Although, not as physically imposing as its brethrens, Alcova provides the essential function it was designed for: diversion of water. Alcova was built at the same time as Kortes Dam, though as a gently sloping earthen dam with a concrete release gate. Alcova Dam and its downriver cohort, Grey Reef Dam, provided a majority of the reclaimed diversion water for irrigating the agricultural lands that dot the landscape from Grey Reef Dam through Casper 30 miles away to Glendo.

Being closest to Casper, Alcova also provides the water for the North Platte that helps feeds the aquifer from which Casper draws 85 percent of its drinking water. (The other 15 percent is drawn directly from the river itself.) Initially, a smaller hydroelectric power station was part of the blueprint at Alcova, though it wasn’t built until almost 20 years after its completion in 1955. At that time, the hydroelectric plant was operated only seasonally based on water running through the generators during irrigation releases downstream to Nebraska. To increase power generation and address other down river issues from Alcova, Grey Reef Dam was built.

Most people, upon seeing Grey Reef Dam ask, "Why?" With this earthen dam's hardly imposing overall height of 36 feet and paltry water capacity of 1,800 acres of water—compare that to the stone 214-foot tall dam and one million plus acres of water stored at Pathfinder Reservoir — it’s easy to quesiton Gray Reef ’s purpose. The dam, though, was special and designed for one reason only: designated as a reregulation dam, its mission was to help maintain water levels for power generation out of the Alcova power plant. Today, though, Gray Reef Dam is much more important to regulating wildly fluctuating water flows out of Alcova downriver. In- stead of the North Platte's water level changing daily with varying discharges from Alcova, the water is held briefly and flows out at a naturally steady pace from Gray Reef. This allows the river to maintain a consistent flow of water through Casper and past the many farms and ranches along the river.

At times, a mud puddle

Traveling south from Casper along the North Platte, small communities such as Glenrock and Douglas dot the landscape. Approaching Glendo, the landscape is flooded for 14 miles. For 10 years during Wyoming's last drought, Glendo resembled a large mud puddle. Outflows from Glendo feed through the dam's hydroelectric plant and then meander almost directly down river to Nebraska. During those drought years, water was held in the Pathfinder and Alcova, while Glendo was allowed to dwindle. Boaters and fishermen, routinely scraped their propellers when coming close to shore. The earthen dam at Glendo is not unique in construction, though it has been a focus of control by Nebraska for years. In 1945, representatives from Wyoming, Colorado and Nebraska signed the North Platte River Decree, regulating the minimum flow of water from the North Platte into Nebraska each season for the irriga- tion of their farmlands. Glendo was set up to control that flow and prevent flooding of the lower Platte Valley. Wyoming is legally bound to release a minimum of 40,000 acre feet of water downriver annually. The annualflows are divided by eastern Wyoming and Nebraska — 25,000 acre feet are distributed to Nebraska and 15,000 to eastern Wyoming. Glendo is the main repository for that allocation, though there have been cases when those flows were deemed inadequate by Nebraska.

Flows between Alcova and Glendo begin to diminish as the year passes, though after leaving Glendo, the flow drops off considerably and meander slowly southeast through Platte County. It is here where it makes its last stop in Wyoming during a journey of more than 200 miles from where the dam system originates in Wyoming. This brings us to Gurnsey Dam, the second oldest dam in the North Platte system, dating to 1928. For farms all along the central and southeastern sections of Wyoming, Gurnsey Dam is a lifeline. With rainfall averaging only 13.5 inches each year, farms would dry up if not for the extensive irrigation system in the area.

Like Alcova, Gurnsey Dam uses a double-dam system to control flow and irrigation. Alcova has Gray Reef; Gurnsey has Whalen Dam, a diversion dam approximately eight miles down stream that redirects Gurnsey outflows to the 200-plus miles of area irrigation canals. After leaving Whalen Dam, Wyoming bids its water rights good- bye, and the slow braided stream that is the North Platte River flows into Nebraska.

Controversy and benefits

Dams have always brought controversy, but Central Wyoming has progressed in large part with the construction of the North Platte dam system. The limitations of original designs were recognized, with early engineers not accounting for fish spawning habits, natural flood patterns and sediment deposits reducing capacity.

posits reducing capacity. In addition, those original court fights over water rights with Nebraska will likely continue as water continues to play an important role in growth and development.

According to John Lawson Area Manager for the Bureau of Reclamation in Casper, that manages the dam system, "Operational improvements have been made to the system over the years, with addition of hydroelectric generators, allowing year-round elec- trical output." Another upgrade Mr. Lawson mentioned was the Pathfinder Dam modification currently underway. "The modification will raise the dam 2.4 feet and allow for the recovery of an additional 54,000 acre feet of water lost to sediment buildup over the last century, returning the reservoir to its intended capacity." These modifications are scheduled to be completed by the end of 2011, however this year’s abundant flows due to run off, may slow the project.

The future

The benefits of the North Platte River dam system abound. In Central Wyoming alone, from Pathfinder to Wyoming's eastern border, irrigated farmland exceeds 226,000 acres because of the dams. Venues for water recreation of all manner abound and bring welcome dollars into out tourist economy. The dams provide flood control down the river. In 2009, 15 years of progressive drought that plagued Wyoming began to abate. Wyoming's dam systems saved it. As water storage levels plunged in our reservoir's due to a lack of rain, we were able to sustain our populations, water our cattle, grow our crops and provide for the water needs of our natural resource industries. If not for the state's dam systems, Wyoming would be as parched, inhospitable and unproductive as it was when pioneers first settled on the land in the 1800s.