PARACHUTE — Colorado residents fighting new oil and gas development — 53 wells and a fracking waste facility on the banks of the Colorado River — have turned to an untested state rule in a last-ditch push for protection. The proposed Ursa Resources wells here, drilled within 1,000 feet of Battlement Mesa homes, also would be near a public water system and a state wildlife area. Colorado Department of Public Health and Environment officials have raised concerns, warning that six storage tanks at the waste injection facility “creates a significant contamination risk to the public water supply” and that a spill could hurt wetlands and the river. “A ban on fracking?