Pershing County Water Conservation District - Irrigation System Improvements
ROGERS DAM FAILURE & RECONSTRUCTION
 Many of the project elements are currently on hold due to the failure of the Rogers Dam. The reservoir that backs up behind the Rogers Dam is diverted into Union-Rogers Canal which provides water to 60% of the ranches in the valley.
According to the State Engineer's Dam Safety Office, the failure of the Rogers Dam occurred on Tuesday, July 18th, 2006, as a result of the very high flows in the Humboldt River that undermined the concrete control section of the dam making it useless. The concrete portion of the dam was completely undercut by four to five feet with the entire flow of the river flowing under it, unimpeded. The undercutting had progressed laterally to the limits of the wing-walls at either end of the control structure, leaving large sink-holes in the embankments at those points.
The downstream spillway apron had collapsed in the middle blocking the flow of water beneath the structure and causing the accelerated lateral erosion at the foundation. A displaced piece of corrugated metal could still be observed at the left wing-wall. Presumably this was installed to cut-off seeps around the control structure or to arrest erosion at the toe of the wing-wall. This may have been a contributing factor to the failure. No water was being diverted to ranches downstream.
No one was injured and no property damage was reported. No damage to downstream facilities was observed due to the dam failure which was consistent with the "low" hazard rating assigned to the structure.
Severe economic hardship would have been experienced by the farmers of the "lower valley" if deliveries to the Union-Rogers Canal could not be reestablished. The PCWCD estimated that approximately 20,000 acres, representing more than half of the land served by the PCWCD, were affected. The PCWCD requested emergency funding assistance through a change in project scope on their existing grant from the Board.
The Rogers Dam could not be "patched" for temporary use. Division of Water Resources - State Engineer's Dam Safety Office, Dyer Engineering, Farr-West Engineering, and the PCWCD worked together to devise a cofferdam design that would provide the quickest and least expensive way to get water flowing into the Union-Rogers Canal. The cofferdam was constructed upstream of the failed Rogers Dam. The PCWCD obtained all heavy equipment available in the region to provide as much in-kind work possible on this temporary structure. Ranchers in the District also volunteered their time and equipment. The District hired West Coast Construction to handle the majority of the construction. The Rogers Dam would need to be properly investigated and repaired/replaced as the cofferdam could not be left in place as a long term stand-alone structure on the river.
The Board for Financing Water Projects held a public meeting on July 28, 2006, to consider reallocating the PCWCD's existing grant funding to help cover the cost of the cofferdam and the investigation of the failure of Rogers Dam and subsequent preliminary engineering necessary to determine the cost of replacing the Rogers Dam.
The Board decided to reallocate $850,000 (85% of a set $1,000,000) of already approved project funding for the construction and costs involved in the emergency temporary dam (cofferdam); for study and construction of an improved by-pass; and for prelimimary engineering and geotech work to begin moving forward on a new permanent structure contingent on the District expending their emergency funds and the District continuing to pursue other state and federal funding. The Board required that the PCWCD come back to the Board with planning and other information as it became available. The only original project element that would move forward would be the Old Channel / Union Canal Diversion Structure as it had match funding from the BOR which was time sensitive. Other project elements previously funded need to be reviewed by the Board in the future prior to obligation of grant funding for those elements. 
Should other state or federal funding be made available for this emergency project, the grant will be refunded so that the originally planned project can proceed.
The cofferdam was constructed during a two week time period between July 23 and July 31, 2006. Flow to the lower valley via the Union-Rogers Canal resumed immediately thereafter with minimal disruption in the irrigation schedule. Geotechnical studies and preliminary engineering design for either rebuilding or replacing the dam were also in progress.
The following are photos of the Rogers Dam site in the summer of 2006 when the cofferdam was constructed to replace the failed Rogers Dam.
(Place your cursor over any photo for a brief summary of what your are seeing. Click on any photo to enlarge - note that the enlarged photo will open in a new window.)
In March 2007, the PCWCD came before the Board to request an additional reallocation of funding from the original grant in order to cover the final costs of the bypass and engineering design for the new Rogers Dam. The Board approved an additional $569,500 in grant funding bringing the total of reallocated funding to $1,419,500 (85% of the total eligible project cost estimate of $1,670,000).
The following are photos of the Rogers Dam site in February/March 2007 when the North by-pass spillway (bypass) around the cofferdam was constructed to protect the cofferdam until the failed Rogers Dam was replaced. Design options for this by-pass included: 1) a pool and step configuration using a gabion baskets/Reno mattresses configuration and 2) a constant slope channel with a stilling basin constructed of articulated block mats and an A-Jacks block system. The second option was chosen because of the expected life of this system, the shorter work schedule (approximately a month less), the earthwork for the site was significantly less, and this system avoided working below the groundwater table.
Construction of the bypass included the following items:
- Cleaning & stripping
- Rough filling & grading
- Gravel fill for rough filling & grading (razor rock)
- Stabilization of stilling basin
- French Drain
- Sheet piling
- Geotexile fabric
- 4-6" drainage layer
- Geogrid-BX1100
- A-Jacks
- Articulated block mats
- Concrete slab under gravel fuse plug
- Stop logs, posts & appurtenances on concrete slab
- 4-50 foot long 54" diameter steel culverts
- Gravel for fuse plug (razor rock)
- Rip-rap
- Engineering design of the north spillway
- Construction inspection & testing of the spillway
The by-pass is a permanent structure and will remain in place. The Board made a visit to the site on March 9, 2007. Water was flowing down the by-pass by March 19, 2007. The project coordination and overall cooperation of everyone involved made this one of the most speedy and successful projects this program has witnessed.
(Place your cursor over any photo for a brief summary of what your are seeing. Click on any photo to enlarge - note that the enlarged photo will open in a new window.)
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Start to Finish - North by-pass spillway around the Rogers Dam and cofferdam
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Start to Finish - New Rogers Dam
 Geotechnical studies and engineering design for rebuilding the Rogers Dam were completed by August 2007. During its 2007 session, the Nevada State Legislature allocated $100,000 from the general fund for replacement of the Rogers Dam (AB 302). In September 2007, the old grant was closed out and the Board reallocated the grant amount remaining from the original grant ($2,571,160) and approved $1,091,861 in additional grant funds to assist in the construction of the new Rogers Dam. The total of the new grant was $3,663,021 (85% of the total estimated eligible costs of $4,309,437). Construction of the new dam began in October 2007 and was completed in May 2008. (Place your cursor over any photo for a brief summary of what your are seeing. Click on any photo to enlarge - note that the enlarged photo will open in a new window.)
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