Fish stocking would mitigate added irrigation, opinion states

Fish stocking would mitigate added irrigation, opinion states

Mar. 24, 2001

By Jim Mimiaga
Journal Staff Writer

The U.S. Fish and Wildlife Service has issued a biological opinion stating that a proposed irrigation project in Montezuma County would jeopardize endangered fish species and their habitats in the Colorado River basin.

But recommended mitigation efforts, outlined in a Recovery Implementation Plan, will allow the $8.2 million expansion slated to irrigate 4,000 acres of dryland farms around Pleasant View to finally become a reality.

"This is the first concrete step in getting the (water delivery) carriage contract, and we accept," said John Porter, general manager of the Dolores Water Conservancy District, which will serve the new lands.

According to the report, released this month, the Dolores Water Conservancy District’s intention to deplete 8,000 acre-feet from the Dolores River basin for new farms "would jeopardize the continued existence of the Colorado pikeminnow, razorback sucker, bonytail, or humpback chub, and is likely to destroy or adversely modify the designated critical habitat of these species."

However, the study, required under the Endangered Species Act, outlines compensation measures for the loss of water in the fishery. The "reasonable and prudent alternative" to avoid jeopardizing the species involves stocking Colorado pikeminnow in the lower Dolores below the Disappointment Creek confluence. In addition the district must pay for monitoring selenium accumulation that might occur as a result of return irrigation flows into the San Juan River basin.

"In the Dolores, our studies show pikeminnow in the last mile or so before it hits the Colorado, but they probably existed further upstream where they will be stocked under the recovery program," said Lee Carlson, field supervisor for the USFWS.

Also as part of the mitigation, the District must contribute $14.75 per acre-foot depleted or $118,000 towards the recovery plan that will stock the fish. In addition the District agreed to contribute up to $80,000 over ten-years towards the selenium monitoring in McElmo Creek, Yellow Jacket Creek, and Sandstone Creek, all tributaries of the San Juan River.

Selenium occurs naturally in soils, but it can be leached out in unhealthy amounts by irrigation-return flows. Fish biologists are concerned that newly irrigated land could flush higher levels of selenium in the San Juan River, threatening the food chain of endangered species and others.

"We agree that the selenium build-up is not likely because the soils to be irrigated are the preferable red soils, but we want to make sure it does not become a problem," Carlson said.

Water delivered from McPhee Reservoir to the land proposed for irrigation is known as a "transbasin diversion" in that the water is pulled from one river basin (the Dolores) and then delivered to irrigate lands that drain return flows into another (the San Juan Basin). As a result, the dilution factor in the Dolores is decreased, while in the San Juan it is increased, altering habitats and the presence of toxic elements such as residue pesticides and herbicides.

While the ESA recovery programs are in place to augment water that lost to depletions in either river, compensation can come in other ways, Carlson said. "Recovery needs also means stocking endangered fish to improve the total recovery of endangered populations and habitat in the Colorado basin," which is fed by the Dolores, Mancos, Animas, San Juan, Gunnison, and Green rivers, among many others.

Special care must also be taken during construction of new project canals to avoid the habitat of the endangered southwestern willow flycatcher and the declining Gunnison sage grouse, according to the opinion.

Porter said that the next step is for the Bureau of Reclamation to complete the environmental assessment on the project.

"If we get a findings of no significant impact, then construction would begin by this time next year," he said.