RENO, NV - The U.S. Bureau of Reclamation's own risk assessment team recommended water flows at less than half the level currently flowing through an irrigation canal that broke and flooded about 600 homes in Fernley in January, an expert testified Tuesday.
The recommendation from a 12-member team of scientists that flows be capped at 150 cubic feet per second ultimately was overruled by a two-member team that determined flows up to 350 cfs were acceptable primarily because the risk of loss of life in the event of another failure was quite low.
But Edward Porter, a geological engineer testifying on behalf of flood victims who want the flows restricted, said he agreed with the original recommendation based on structural weaknesses he has observed in the canal embankment.
"Based on my observations, I think we were very lucky not to have lost lives," Porter said Tuesday during a hearing before U.S. District Court Judge Lloyd George.
The hearing was a continuation of a proceeding that began last week. It was continuing Tuesday afternoon.
"The bureau's own experts agreed with us, but they were overruled by people who want more water in the canal," said Bob Hager, a lawyer representing flood victims.
Hager is seeking a restraining order to limit flows at a maximum of 250 cfs. George refused that request last week but has ordered the bureau to conduct daily inspections while he considers the matter further.
Officials for the Truckee Carson Irrigation District who operate the canal for the U.S. Bureau of Reclamation argue that cutting flows below 350 cfs would have a significant economic impact on about 2,000 farmers and ranchers who already are faced with less-than-normal water supplies for their crops and livestock this summer.
The bureau's 12-member risk assessment team made up of civil engineers, geotechnical engineers, a geologist and a hydrologist did not specifically address a flow rate of 350 cfs. However, they concluded in a report in February that a flow of 450 cfs would result in a "moderate to high" probability the canal would fail again within the next year while a flow of 150 cfs would result in a "low to moderate" probability of such a failure.
The second team that conducted a Design, Estimating and Construction (DEC) Review was led by Perry Hensley, the bureau's dam safety officer and a senior adviser for design, estimating and construction oversight.
Jack Delp, a retired bureau consultant, also assisted in that review.
Their evaluation issued in March concluded that the risk
assessment team's recommendation to limit flows to 150 cfs was "overly conservative given the remote possibility of loss of life as demonstrated by the recent failure and represents a significantly higher standard of performance than is typically required for new canals."
"Based on recent investigations, past performance and the risk assessment team's estimation of likelihood of failure, the DEC Team believes that with the present conditions of the embankments, limiting interim (1 to 5 years) canal flows to 350 cfs would be a reasonable operational constraint commensurate with the identified risk for canal failure," that report said.
No one was killed in the Jan. 5 flood about 30 miles east of Reno, but 590 homes were flooded, including an estimated 140 that sustained moderate to severe damage.