Water released from Lake Mead, through Hoover Dam’s turbines, travels downstream about 150 miles to Lake Havasu. There, massive pumps on the river’s left bank push the water up on the start of a 336 mile journey that ends in groundwater spreading basins west of Tucson. The Colorado River’s water then recharges an aquifer, where it can then be pumped and mixed with others sources of supply so that, at 3:35 p.m. on a hot August afternoon, you can keep this little patch of lawn at the Tucson Museum of Art green, and the patio wet.