Keswick Dam

Keswick Dam
Country United States
Location Shasta County, California
Coordinates 40°36′43″N 122°26′45″W / 40.61194°N 122.44583°W / 40.61194; -122.44583Coordinates: 40°36′43″N 122°26′45″W / 40.61194°N 122.44583°W / 40.61194; -122.44583
Construction began 1941
Opening date 1950
Owner(s) U.S. Bureau of Reclamation
Dam and spillways
Type of dam Concrete gravity
Impounds Sacramento River
Height 157 ft (48 m)
Length 596 ft (182 m)
Dam volume 214,000 cubic yards (164,000 m3)
Spillways Gated overflow
Spillway capacity 250,000 cu ft/s (7,100 m3/s)
Reservoir
Creates Keswick Reservoir
Total capacity 23,800 acre·ft (29,400,000 m3)
Catchment area 6,380 sq mi (16,500 km2)
Normal elevation 601.6 ft (183.4 m)
Power station
Turbines 3
Installed capacity 117 MW
Annual generation 383 million KWh

Keswick Dam is a concrete gravity dam on the Sacramento River about 2 miles (3.2 km) northwest of Redding, California. Part of the Bureau of Reclamation's Central Valley Project, the dam is 157 feet (48 m) high and impounds the Keswick Reservoir, which has a capacity of 23,800 acre·ft (29,400,000 m3). Its powerplant has three turbines with a generating capacity of 117 megawatts (MW) uprated from its original 75 MW in 1992. The dam and reservoir serve as a forebay to regulate peaking power releases from the Shasta Dam upstream. The electrical substation at Keswick Dam distributes power not only from the Keswick powerplant but also from powerplants at Trinity Dam and Lewiston Dam, as well as the Judge Francis Carr Powerplant near Whiskeytown Lake and the Spring Creek Powerplant, located just northwest of Keswick Dam.

History

Early proposals

Keswick Dam was one of Central Valley Project that was started due to unequal water allocation that left some land owners with no water supply especially during summer season when need of water diversions for irrigation and domestic uses was required due to prolonged hot and dry weather.[1] The water scarcity started in the 19th century in gold mine Era. Discovery of the gold mine in the 1840s attracted flood of immigrants to California. After a few years many immigrants attention shifted to agriculture because it seemed more stable than gold gambling. Central valley had fertile soils, abundant water, and a flat gentle topography suitable for farming.[2] Consequently, dust bowl depression era caused more migration to California resulting to further extension of agriculture and ranching in gold fields. The California Legislature immediately enacted laws to deal with the state's water scarcity issue, so they adopted riparian water rights.[3] This law had limitations where owners of land bordering the water had a right to a reasonable amount of that water but Owners, whose land did not border bodies of water, had no rights to any of the water. Due to the usage restrictions by the riparian rights, the government directed the state engineers to come up with a plan for the entire state to accomplish fair distribution of water for irrigation and domestic uses. Increase in demand for food caused a shift from a small scale farming to large scale intensive farming. Low topography caused flooding in winter rainy season, but later followed severe drought in summer months. Low water flow cause increase in salinity that resulted in intrusion of salt in some parts of the valley especially in the Bay. Primarily, Keswick project was for irrigation purposes,but it become a multipurpose for flood control, improves Sacramento River navigation, supplies domestic and industrial water, generates electric power, conserves fish and wildlife, creates opportunities for recreation, and enhances water quality.[1]

Central Valley Project (CVP)

Shasta division is part of CVP that consist of Keswick Dam and power plant, Shasta Dam and Lake, and Shasta power plant.[4] Keswick dam acts as Shasta dam’s after-bay stabilizing the erratic water flow released through Shasta power plant. Keswick reservoir captures water diverted from the Trinity River through the trinity river division.[5] Keswick power plant further generates power using Sacramento River. The CVP is a major water conservation developments extending from the Cascade range in the north to the semi-arid but fertile plains along the kern river in the south. It was built mainly to deal with flooding issues and water shortages, but as time progressed more missions came into play due to development of canals, power plants and more dams. CVP plan was passed by the state legislature in 1933 but the project was not constructed until the federal government assumed control of the project and its initial features were authorized for construction by the U.S. Army Corps of Engineers. Funds for construction of the initial features of the Central Valley Project were provided by the Emergency Relief Appropriation Act of 1935. Later, U.S. Bureau of Reclamation took over CVP construction and operation, and the project became subject to Reclamation law under the 1937 act with three objectives: regulate rivers and improve flood control and navigation; Provide water for irrigation and domestic use; and generate power. Shasta diversions are among the major projects of CVP and the projects were approved in the late 1930s [2]

Construction

Keswick Dam named after the lord Keswick president of the Mountain copper company, limited. The project contract was initiated by the U.S. Bureau of Reclamation to Guy F. Atkinson Company and Kiefer construction Company and started operation in August 1941.[4] Operations began immediately but loss of labor was experienced due to problems by the Central Valley, but U.S bureau of reclamation gave a go ahead. By end of 1941, the foundation was completed despite the labor challenges by the Guy F. Atkinson Company. During building of the concrete, weather changes was another issue. In the summer months, the workers had to spray water over the aggregates to lower temperatures due to extreme hot temperatures. In the winter, workers heated the mixture to keep the temperatures above 50 degrees. During rainy seasons the construction was stopped due to flooding.[3] In 1944 during end of World War II, there was workers strive for about a month due to Atkinson earlier agreement to raise workers’ wages. Workers returned after promised by the War Labor Board to consider the wage issue and the end of 1944 the agency increased the wages. In December 1947 exhaustion of funds had altered building of the dam, however the powerhouse structure was completed. Atkinson-Kier completed the Keswick spillway, and repaired eroded portions of the spillway apron in July 1948. Wismer and Becker installed two of the generators at Keswick Power plant in 1949. Reclamation placed generator Units Two and Three into operation. The firm placed the fifty by fifty foot spillway gates at Keswick early in 1950, and they started operation on February 20. Wismer and Becker installed the final generating unit at Keswick power plant on March 31, 1950 [4]

Hydro-meteorological aspects

Climate

The climate in Shasta County can be characterized as hot and dry in the summer, and cool and wet in winter, with the best climate occurring in the spring and fall seasons. The simplest method of analyzing climate of place is by using statistics to get the average annual rainfall and temperatures.[6] The heavy precipitation period fall in the months of October through March with average annual precipitation about 69 inches. June through September receives very low rainfall reducing the inflow. Consequently, temperatures are very high in summer ranging mid 80- 90◦ F. In winter temperatures are lower averaging 40◦ F.[7] In summer, there is a significant increase of discharge from the Dam due to more demands of water especially for agriculture use. High temperatures increase rate of evaporation, so more water is needed to sustain the crops.

Hydrology

Keswick and Shasta Dam manage the stream flow of the Sacramento river below river mile 302. In summer Shasta lake increases the inflow discharge significantly despite the prolonged dry months that reduce the discharge. Water from the Whiskeytown Dam and clear creek reservoir is released to the Sacramento River by way of Keswick Reservoir to meet demand for water in Southern California. Under normal project flood conditions, the flood plain width ranges from 200– 500 feet below Keswick dam. The river bed is constructed with course gravel at the riffle locations and fine sediments at non riffle locations.[8]

Water quality

Acidic sludge in Keswick Reservoir, forebay of the Shasta Dam near Redding

Iron Mountain Mine was a widely known sulfide ore deposit mine that provided valuable metals, but soon lost its fame due to extreme acid mine drainage and contaminated sediments deposits. The contaminated metal sediments that precipitated from the mine drainage accumulated in the Spring Creek Reservoir (California) and Keswick Reservoir on the Sacramento River. The mine was located in Shasta County adjacent to Keswick Reservoir and has been known to be the largest toxic metal contributor to Sacramento River System.[9] Copper was identified as the main pollutant to the river but other contaminants that caused degradation of water quality were: copper, iron, zinc, cadmium, mercury, lead and Acid water.[10] The total concentration of metals recorded in the river as been as high as 200g/L and the water acidity recorded was negative PH 3.6.[11] In Sacramento River Delta, other inactive mines have contributed to the degradation of water quality of Keswick Dam. Although various agences like clean water act and Environment protection agency dedicate to improve the quality of drinking water by treating the contaminats, uncontrolled Acid mine drainage still pose a great threat to the quality water in the area. The quality of surface water downstream of Keswick Dam is also influenced by other human activities along the Sacramento River downstream of the dam,including agricultural, historical mining, and municipal and industrial inputs. In the year 2000, the water quality of Sacramento river was reported to be relatively good. However, Water temperature is a principal water quality issue in the upper Sacramento River between Keswick Dam and Red Bluff Diversion Dam (RBDD). Other unknown traces of mercury,pesticides and metals have also been recorded in the 26-mile reach from Keswick Dam to Red Bluff [12]

The city of Redding, California where Keswick dam is built is primarily made up of volcanic and sedimentary rocks that are metamorphosed [13]

Aesthetics

Keswick Dam is surrounded by chaparral community, riparian vegetation and a steep terrain. Around the dam is Keswick Lake and Keswick Reservoir that provide water to the dam and also help stabilize releases from Shasta dam. Upstream from Keswick Reservoir, slopes are characterized by a mix of pine and oak forests and, to varying degrees, chaparral and rock outcrops. The landscape includes topographic features of the Klamath Mountains, the southern Cascade Range, and the Central Valley. Two volcanic features – Mount Shasta and Lassen Peak – can be seen from numerous vantage points throughout the area [4]

Biological aspects

Wildlife and fisheries

Keswick Reservoir is among the aquatic environments associated with the Sacramento River watershed.[14] Cold-water fish species found in Keswick Reservoir include resident rainbow trout and brown trout. Warm-water species include the same species found in Shasta Dam. California Department of Fish and Wildlife occasionally plants hatchery-reared fish in Keswick Reservoir. The reservoir is accessible from shore and by boat, but it is not heavily used for fishing. Keswick Dam is the uppermost barrier to anadromous fish migrating up the Sacramento River. Because of its small size, Keswick Reservoir does not stratify. Reservoir levels fluctuate daily by one to three feet. The reservoir can fluctuate as much as eight to nine feet on an annual basis. Releases to the Sacramento River have ranged from approximately 3,300 cfs (Department Of Water Resources, 2011) during drought periods and 79,000 cfs during flood events ( Department of Water Resources,1974).[15] From Keswick Dam to the Red Bluff, California, the river is relatively narrow and deep with some areas of broader alluvial floodplain. Most of the Chinook salmon spawning habitat in the Sacramento River is located in this reach. The variability and magnitude of natural seasonal flows on the Sacramento River have been significantly altered for the purposes of irrigation and flood control. The dams and diversions operated by the Central Valley Project and local irrigation districts control much of the flow in the Sacramento River. To protect holding and spawning winter-run Chinook salmon, Reclamation has been required to manage cold-water reservoir storage and releases to maintain daily average water temperatures at or below 56 °F between Keswick Dam and compliance locations between Balls Ferry and Bend Bridge from May 15 to September 30 since 1993 [16]

Ecological effects

Iron Mountain Acid Mine Drainage.The mine was in operation from 1860 s until 1963

Iron mountain mine and Pyritic ore mining both in Shasta county have contributed to the degradation of Sacramento river in addition to killing of fish and other aquatic organisms downstream of Sacramento river off Keswick Dam.[17] This is as a result of acid in water and other metal deposit contaminating the sediments quality in the river. Exposure to copper and other metals alter the physiological and reproductive alterations in salmonid species in Sacramento River below keswick dam. Winter run chinook salmon spawn in the river is one of the major salmonid species threatened. Endangered Species Act. Spring creek reservoir was built to control the drain prior discharge into keswick reservoir. The acid previously recorded to range between PH 1.5 to -3.6 improved to a PH of about 3( EPA 1992). All the acid mine drainage and the discharge deposits had to be diverted into the treatment plan. This also improved the concentrations of metals by about 97 percent under regular operating conditions. Currently the water quality of characteristics at spring creek debris dam outlet to keswick reservoir meet the water standards for sacramento river that are set and regulated by water control board (usbr.org/ spring water sampling report).

See also

References

  1. 1 2 "Keswick Powerplant". www.usbr.gov. Retrieved 2016-05-13.
  2. 1 2 "Central Valley Project". U.S bureau of reclamation. Retrieved 14 April 2016.
  3. ↑ Lassiter, Allison (2015). Sustainable Water: Challenges and Solutions from California. Oakland California: University of California press. p. 52.
  4. 1 2 3 4 Stene, Eric. "Shasta Division, Central valley project" (PDF). U.S Bureau of reclamation. Retrieved 18 April 2016.
  5. ↑ Stene, Eric. "Trinity Division: Central Valley Project". Related Documents Trinity River Division Project History (52 KB) (pdf). Retrieved May 13, 2016.
  6. ↑ "Statistical Weather and Climate Information". National Centers for Environmental Information. Retrieved May 13, 2016.
  7. ↑ http://www.usclimatedata.com/climate/shasta/california/united-states/usca1045
  8. ↑ Wild, scenic, and recreational characteristics : Sacramento River, California, Keswick Dam to Sacramento. Sacramento : Dept. of the Army, Sacramento District, Corps of Engineers. 1975.
  9. ↑ (www.Epa.gov)
  10. ↑ (http://ca.water.usgs.gov/projects/iron_mountain/environment.html
  11. ↑ http://www.toxins.ucgs.gov
  12. ↑ https://www.usbr.gov 3, geologic features
  13. ↑ "Keswick Dam–Red Bluff Reach" (PDF). keswick dam–red bluff reach - Sacramento River. Retrieved May 13, 2016.
  14. ↑ "Sacramento River Watershed Program". www.sacriver.org. Retrieved 2016-05-14.
  15. ↑ "California Department of Water Resources". www.water.ca.gov. Retrieved 2016-05-14.
  16. ↑ "California Natural Diversity Database Home". www.dfg.ca.gov. Retrieved 2016-05-14.
  17. ↑ "Acid Mine Drainage". Environmental Effects of Iron Mountain. Retrieved May 13, 2016.
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