Fifty House members and 22 senators signed a letter Wednesday urging the Bureau of Land Management to accept public comments on the environmental impact statement for the project through Dec. 1. That would add 90 days to the original Sept. 9 deadline.
There are 75 House members and 29 senators in the Utah Legislature.
Four arguments in favor of the extension are identified in the letter, including the difficulty for the impacted farmers and ranchers to review the EIS during their busy summer months. Legislators also expressed concern about the technical nature of the document, which is hundreds of pages and took six years to compile before being released in June.
"A more deliberative process will produce better comments which will better inform BLM's decision-making," lawmakers said in the letter.
The request from state officials is being sent on the same day that the Great Basin Water Network, a coalition opposed to what they describe as a "water grab" by the Southern Nevada Water Authority, released a summary of the negative impacts found in the BLM document.
Among the "irreversible" changes highlighted by the group from the EIS are increased dust pollution as groundwater levels reduce, changes to wildlife and fish habitats and the decimation of ranches and farms that are the economic base of the impacted areas.
J.C. Davis, spokesman for the Las Vegas-based water authority, said the feared impacts on water levels won't happen because the BLM doesn't take into account planned mitigation efforts or groundwater monitoring.
Davis also said the BLM contradicts itself by claiming fugitive dust will become a problem as vegetation disappears. Yet, in a different part of the study, the BLM said vegetation will not disappear but will transition from deep-rooted to shallow-rooted plants.
"The argument of increased dust doesn't work," Davis said. "There are lots of valleys in Nevada and Utah where (shallow-rooted) plants are common."
The dispute over the water pipeline is of particular concern for Utah's political leaders because it would take water from the Snake Valley in western Utah, near the Nevada border. The water that feeds the valley comes primarily from mountains in Nevada.
Both states have established a team of negotiators to craft a water-sharing agreement that includes environmental protections that could derail continued pumping if detrimental impacts to sensitive species occur or the water table is drawn down significantly.
If water use by existing users is compromised, the agreement also establishes a fund to compensate existing users.
That agreement, however, is in limbo, given a June ruling by the Nevada Supreme Court that said the Nevada water engineer failed to adequately address environmental protections in the four Nevada valleys of Spring, Cave, Dry Lake and Delamar.