The annual summary of water-resources activities in Colorado is presented for fiscal year 1987. The report includes an introduction of these activities and names of the management personnel to whom information requests may be addressed; a summary of the U.S. Geological Survey mission and of the Water Resources Division mission; and a discussion of the water resources in Colorado in fiscal year 1987, including data collection on surface water and groundwater. All current Colorado hydrologic investigations are listed - their problems, objectives, approaches, progress, and plans for fiscal year 1987. A list of current cooperators for fiscal year 1987 and a list of reports published or released during fiscal year 1987 also are given.