While there has always been competition for water in Colorado, today's contenders no longer just include farmers, but the oil and gas industry too.

The Denver Post reports that an auction hosted by the Northern Water Conservancy District for unallocated water diverted from the Colorado River Basin saw top bids from hydraulic fracturing companies.

Hydraulic fracturing or "fracking" is a process of extracting gas from the earth's shale rock layers using first vertical and then horizontal drilling methods, so that the pipe makes a deep "L" shape underground. Through that pipe, a mixture of water, sand and chemicals (also known as fracking fluid) is pumped down into the shale to break up the rock and extract natural gas.

A concern raised by Gary Wockner, director of the Save the Poudre Coalition, is that water first used for agriculture can stay in the hydrological cycle longer, but water contaminated by fracking is generally removed completely.

"Any transfer of water from rivers and farms to drilling and fracking will negatively impact Colorado's environment and wildlife," Wockner said.

Last month Congresswoman Diana DeGette and Congressman Jared Polis asked President Obama to support stronger environmental and public health standards.

DeGette stated in a press release:

In Colorado, our public lands are central to our recreation economy, and I couldn’t be more supportive of President Obama and Secretary Salazar’s move to require drilling chemical disclosure on public lands. However, with drilling in Colorado increasingly happening next to suburban homes and schools, it’s essential to disclose fracking chemicals anywhere they’re used in order to protect the public’s health in populated areas where those chemicals are most likely to affect our air, water and health.

In 2010, Wyoming became the first state to require that energy companies disclose chemicals injected into the ground, though not chemicals identified as trade secret. Environmental groups are currently seeking to force a more full requirement of disclosure in state court.

(A website in support of the Fracturing Responsibility and Awareness of Chemicals Act (FRAC) features an interactive walk-through of the dangers and controversy surrounding fracking. The bill was introduced to Congress in 2009 but did not pass.)