First, direct the water that falls on the land to places it is needed. It's inexpensive to shape the land to put stormwater where you want it. At our house, this stormwater is directed in turn into four small catchment basins, each with a fruit tree. The trees seem not to mind being underwater a couple times a year when we get heavy rains. We can keep on our property the first inch of rain in a day, reducing flooding concerns.
In Tucson, they have cut curbs so rainwater goes into similar tree wells. Why are we directing rainwater into stormwater systems which then have to be processed by wastewater treatment facilities? We are paying to clean rainwater! In a desert. The Alliance encouraged Sedona to include more "green infrastructure" in our stormwater plan. See the pictures in this article.