Pershing County Water Conservation District - Irrigation System Improvements
PITT-TAYLOR DIVERSION SYSTEM
(Information from the Pershing County Water Conservation Master Plan, December 2005, by Farr West Engineering.)
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The Pitt-Taylor Diversion Structure is located on the Humboldt River near Mill City. In 1913 the Humboldt-Lovelock Power and Irrigation Company (HLPIC) built the Pitt-Taylor Diversion Dam, Diversion Structure and Diversion Canal.
The Pitt-Taylor Diversion Dam (also known as the Thacker Dam) is in poor condition. The dam consists of ten buttresses with eleven flashboard bays. There is visual evidence of deterioration on all of the buttresses, some with as much as fifty to seventy five percent surface spalling. All of the buttresses have cracking with some cracks extending completely through the buttress. The river channel both upstream and downstream of the dam is in poor condition. Erosion has caused the formation of a shoal on the upstream side blocking at least three of the dam’s eleven bays. The exclusive use of flashboards to control flow through the dam is also a concern. Flooding in May and June of 2005 made it nearly impossible to reach the flashboards to regulate flow creating a safety hazard for PCWCD personnel. The flashboards are also difficult to remove and replace due to advanced deterioration of the keyways in the buttresses.
The diversion structure is also in very poor condition. In addition to spalling, parts of the structure have completely disintegrated, exposing the steel reinforcing bars. The Pitt-Taylor Canal supplies water to the Pitt-Taylor Reservoirs and to a single user (Flying M Ranch). There are only two structures in the canal between its origin at the Pitt-Taylor Diversion and its destination at the Upper Pitt-Taylor Reservoir. The first, the Flying M diversion, is approximately 2.6 miles downstream of the Pitt-Taylor Diversion, is in poor condition and unable to handle the original designed flow capacity of 300 cfs. The second structure is a bridge crossing the canal near the diversion structure that provides access to the Flying M Ranch.
The Pitt-Taylor Diversion Canal originates at the Pitt-Taylor diversion dam on the Humboldt River and ends approximately 13 miles downstream (generally west) at the inlet of the Upper Pitt-Taylor Reservoir. The Upper and Lower Pitt-Taylor Reservoirs hold 20,000 and 15,000 acre-feet, respectively. The condition of the canal itself varies from fair to poor along its 13-mile length. Five miles downstream of the Pitt-Taylor Diversion the canal bank has been breeched. Much of the canal is overgrown with tamarisk and other invasive plants. In many areas the canal cross-section is inconsistent with the original design dimensions in width and depth.
High water years occur on the Humboldt River approximately once every 10 years. The last high water years were 2005 and 2006. Renovation/replacement of the elements of the Pitt-Taylor collection system will provide the mechanism to capture and store this additional water during these high flow years.
In addition to the benefits in allotments to the irrigators during drier years, storage in the Pitt-Taylor Reservoirs provides public benefits including: increased water for boating, fishing, hunting and other recreation; use of the Pitt-Taylor reservoirs for growing juvenile fish; and increased habitat and nesting grounds.
In the fall of 2009, the full 13 miles of the Pitt-Taylor Canal were renovated to provide optimal flow to the Pitt-Taylor Reservoirs when water is available. Water conservation is of critical concern.
In April of 2011, the construction of the new Pitt-Taylor Dam and Diversion Structure, Flying-M Diversion Structure and Flying-M Bridge were completed.
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Reconstruction of the Pitt-Taylor Canal
Construction of the Pitt-Taylor Dam/Diversion structures, Flying-M Ranch Diversion Structure, and Bridge at Flying-M Ranch.