GLENWOOD SPRINGS — The state of Colorado’s investigation into the feasibility of a demand-management program has spawned the spinoff of several additional groups to study the issue, underscoring persistent tensions between the Western Slope and Front Range water managers. In June, the Colorado Water Conservation Board named 74 people — most of them experts in their fields — to nine workgroups charged with helping the state study whether a water-use reduction plan is right for Colorado.