From August 24 to 30, Rocky Mountain National Park will close the Colorado River Trail and the Grand Ditch for work on a project that could help save the greenback cutthroat trout, Colorado’s state fish. Since immigrants began arriving to the Front Range in the mid-1800s, mining pollution, fishing and water diversions from streams for agriculture have caused the greenback cutthroat trout population to decline rapidly, the Center for Biological …