Shasta Dam - Future Expansion

Future Expansion

In the 1990s, with skyrocketing water shortages in the Central Valley and some of California's largest agricultural coalitions including the Westlands Irrigation District calling for a more dependable water supply, the Bureau of Reclamation suggested the expansion of Shasta Dam. The expansion is considered feasible because the dam's foundations were originally built to carry the weight of a 800-foot (240 m) structure, but resources shortages at the onset of World War II prevented completing it to its final height.

Reclamation has suggested three options for the dam raise, ranging from less than 20 feet (6.1 m) to more than 200 feet (61 m). The "low option", which simply comprises adding a vertical concrete dike to the top of the dam, would provide maximum additional storage while minimizing requirements for reconstruction of buildings and facilities around Shasta Lake. The "intermediate option" would require adding more than 100 feet (30 m) to the crest and replacing the elevator towers on the front of the dam, and the Pit River Bridge and small towns around the lake, if not modified or moved, would be inundated. Finally, the "high option" would raise the dam over 200 feet (61 m), tripling the volume and doubling the surface area of the reservoir. Both the intermediate and high options would require saddle dams constructed at key points along the lake to keep it from overflowing.

The intermediate and high dam raises would allow for increased generation of hydropower. Each would require the construction of a new powerhouse to accommodate five new turbines; for the intermediate expansion, five 215-MW generators would be added for a total capacity of 1,751 MW, while for the high one, there would be five new 260-MW units for a maximum capacity of 1,976 MW. Downstream Keswick Dam would also be raised and its power station retrofitted to accommodate the greater peaking releases from Shasta.

The proposed dam raise has met with significant backlash from area inhabitants, fishermen, Native Americans, recreationalists and environmentalists. First of all, with any increase to the dam's height, significant reaches of the Pit, Sacramento, and McCloud Rivers would be inundated. The McCloud is an area of special interest because it is one of California's best trout fisheries and because many sacred Native American sites lie along its banks. Opponents of dam raise contend that it would cost more (starting with replacing over 600 structures that would be inundated under the lake including the Pit River Bridge) than its benefits. The water supplied from such a raise would be costly and could be saved if Central Valley farmers cut their water use by only a fraction. It would result in more problems for the ecology of the lower Sacramento, not least its dying salmon runs.

One of the most important points made by dam expansion opponents is that raising the dam will not create more water (in fact it will actually cause some water loss due to evaporation) but merely increases the capacity to store it. As a result, the reservoir will rarely be filled, as no matter how much Reclamation expands the dam, the river's flow will not increase. The cost of the dam raise is projected at $500 million-$1 billion. One of the expansion's most stoic opponents is the Winnemem Wintu tribe, almost all of whose land was inundated by the construction of Shasta Dam. Raising the dam would destroy much of their little remaining land.

Some progress has been made towards the dam expansion including for the completion of a costly EIR (Environment Impact Report) by the Bureau of Reclamation – and the purchase of over 3,000 acres (1,200 ha) of land along the McCloud River by Westlands Irrigation District to help the Bureau gain rights to expand the dam; Westlands believes that the added storage of the dam would greatly benefit its farmers. As of 2007, the irrigation district has spent $35 million. However, Westlands has had a spotty record with environmental responsibility and has been criticized by environmentalists for high levels of pesticide and selenium in the toxic runoff waters from farms operating under the district.