Lawmakers are also working on bills that would give tax credits to people who let their unused water flow downstream and to give the state water conservation board $1 million to buy or lease rights to water that it can then allow to flow rather than be diverted.

The board is the only body allowed to hold such instream rights, as opposed to water rights in which water is taken out of the river to irrigate crops or support cities. Currently, it doesn’t have any money to buy the rights or pay the legal fees for people who want to donate or lease their unused water.

All three bills are backed by Trout Unlimited and Environmental Defense, which released a study Wednesday saying that increasing instream flows would add another $4.4 million a year to the state’s economy because of increased rafting and fishing. The study was paid for by Environmental Defense.

Mitch Kirwan, co-owner of Mo Henry’s Trout Shop in Fraser, said it will become more difficult for fish to thrive in the Fraser River, especially in warm weather, if more water is diverted to the populous Front Range.

Kirk Klancke, who manages the water district for a nearby subdivision, said the development has rights to water it needs to provide for future development but doesn’t need now. He said the district would like to let the water flow downstream to help fishermen and others who use the river but, fearing the district would lose its rights, each year he uses the extra water to irrigate part of an old ranch.

Kirwan said adding more water to mountain rivers like that would help his business besides helping the environment.

“It’s a huge boon for the economy of the mountain areas,” Kirwan said.