Project modernizes open-canal system
New piped system will reduce pollution, require less labor
By JOHN O'CONNELL
ARIMO, Idaho -- As a shareholder with Portneuf Irrigating Co., Randy Morris should soon have cleaner water requiring less labor to replace worn sprinkler heads, and the improvement won't cost him any money.
In late April, the canal company broke ground on a $3.6 million to $4 million project to replace its antiquated ditch with a piped system. The project should also improve the health of polluted Marsh Creek, which flows into the Portneuf River a few miles upstream from Pocatello.
A grant from the Agricultural Water Enhancement Program, part of the 2008 Farm Bill, covered 75 percent of the project's cost. The company had considered an Idaho Department of Water Resources loan to cover its match, which could be up to $1 million, but opted instead to generate the revenue by selling more shares to its 25 farmers.
Morris, who raises cattle on irrigated pasture and grows alfalfa a mile south of Arimo, said existing shares will be worth slightly less water once new shares are issued. He doesn't intend to purchase new shares, believing the new system will be 20-30 percent more efficient and should more than offset the difference.
In an open canal system, lateral canals are filled, and the water that doesn't get used returns to Marsh Creek, lost to the user. The new system will work like a faucet. Work on the canal will stop during the irrigation season and resume in the fall. The goal is to have it ready by the start of next season.
B.J. O'Doherty, district conservationist with the Pocatello office of the Natural Resources Conservation Service, which administers AWEP funding, said the piping project was initially included in a $24 million canal upgrade also involving the Portneuf Marsh Valley Canal Co. The partner intended to cover its match by selling the water savings to the City of Pocatello but withdrew when legal challenges stopped the transaction.
The pipe, which runs from the Portneuf River near Lava Hot Spring to south of Arimo, will carry 50 cubic feet per second and will be 42 inches wide at its broadest point, said Portneuf Irrigating Co. President Chris Robinson. Since it will be buried and won't have to follow the contours of the land, the piped system will be 5.8 miles long, compared with the current 8.6-mile system. The new system should also eliminate the need for screening by individual growers and reduce their electric bills for pumping water, he said.
Robinson, owner of the Arimo Ranch, said weeds in the current canal are burned each spring, and the ash and sediment are flushed into Marsh Creek, which is listed as impaired for sediment and phosphorus. Robinson partnered with government agencies on a 10-year project intended to improve water quality in Marsh Creek by planting vegetation on banks and fencing cattle off.
Lynn Van Every, regional water quality manager with the Idaho Department of Environmental Quality, said the state put almost $1 million of federal non-point source grant money in Marsh Creek in the last six years.
"Any project that can be put into place to alleviate annual maintenance issues (on canals) is going to help water quality," she said.