STEAMBOAT SPRINGS — Western water managers are likely to be the "first responders" to climate change as reservoirs become harder to fill and snow-dependent water systems yield less.

"Climate change is upon us now, and it will have an impact on all of our systems," said David Behar, a planner with the San Francisco Public Utilities Commission.

Behar's comments came today at a meeting of the Colorado Water Congress. Nearly 200 water officials from across the state are meeting to examine what new tools are needed to forecast changes and how to operate water systems as spring runoff cycles change.

"It will affect us first, and it will affect us worst," Behar said.

In Colorado and other Western states, roughly 80 percent of annual drinking water supplies come from high-country snows. Early studies in San Francisco show its high altitude reservoirs will likely be harder to fill as snowpacks shrink and melt earlier.

Water managers have been stymied in responding to a warming environment because climate models are built globally and don't provide enough local or even regional data to reliably forecast changes to snowpack.

A new coalition of western water utilities is hoping to change that by paying for more detailed, regional water models.