PAG helps region manage this scarce resource
The seasonal monsoon brings welcome rains to the desert. If not properly managed, however, stormwater runoff can pose health or safety risks.
“In this metro-area, many of our streets were designed to convey stormwater,” said Mead Mier-Welborn, a planning manager for Pima Association of Governments. “Monsoon stormwater runoff can carry enormous volumes of rain, debris, pet waste, and even unsafe pollutants into watercourses.”

As the greater Tucson region’s federally designated water quality planning agency, PAG is required to create and implement an Areawide Water Quality Management Plan. Also known as the 208 Plan, in reference to Section 208 of the U.S. Clean Water Act, the document defines regional integrated planning of wastewater, stormwater, surface water, groundwater and solid waste, and is approved at the state and federal levels.
PAG works with Tucson-area jurisdictions to develop and implement strategies to minimize the potential harms associated with stormwater runoff and takes a role in helping to promote these strategies and programs to raise public awareness.
The region’s washes and rivers, which typically run for brief periods during the year and sometimes dangerously fast, provide rare and valuable habitat for desert plants and animals as well as serve as an important water supply for many species. Keeping these fragile areas free of pollutants is important to the continued protection of the Sonoran Desert.
The public can do simple things to protect our watershed from dangerous runoff. One of these is as easy as cleaning up after your pets. Animal waste is a major contributor to stormwater pollution.
“E.coli can be found in animal waste and is an indicator of pathogens in stormwater,” Mier-Welborn said. “Its presence in stormwater is often traced to dogs.”
By cleaning up after your dog when taking walks in your neighborhood, in the desert, or along washes and riverbeds, you can keep their waste from being washed into waterways and polluting scarce water resources.
Using alternate modes of transportation and keeping cars in proper working order also can help minimize the amount of chemicals that enter the watercourses. This includes motor oil, engine coolants, brake fluid, and other chemicals that can leak from poorly maintained vehicles and can be carried into rivers and washes in street runoff.

Be mindful when you apply household chemicals such as herbicides, pesticides, paint, and other products. Many of these products can be washed away when the rains come and find their way into watercourses. By waiting until the chances of rain are minimal, you can keep these materials out of the washes and ensure you get your money’s worth out of them by not having them washed away.
By incorporating green stormwater infrastructure into landscaping and home design, you can further minimize the amount of debris and harmful substances that escape into the environment. Green infrastructure refers to the use of nature-based solutions to retain and use stormwater on your landscape for environmental and community benefits, such as tree shade.
This can mean creating passive rainwater harvesting systems to use on your property to water vegetation. By using simple, low-cost, low-tech rock berms and digging out strategic contours, you can slow the amount of runoff from your property and minimize the amount of potential pollutants that get into the environment.
Local governments also have incorporated green infrastructures into streetscapes and other municipal projects. The use of curb cuts can provide water for landscaping and allow water to biologically break down pathogens from pets and hydrocarbons from vehicles in small manageable quantities. The results of harvesting the water are more resilient vegetation and pleasant landscape for people walking, biking, sitting at bus stops or living along the corridor. Larger projects, such as neighborhood water retention basins, can help prevent roadway flooding during rainy seasons and provide passive recreation options when dry.
“Our community treasures monsoon storm waters and understands how important it is to maintain this limited resource,” Mier-Welborn said.
Clean water starts with me: A monsoon primer
Monsoon: The summer rainy season in the desert Southwest runs from June 15 to Sept. 30. A general wind shift during this time of year brings tropical moisture up from Mexico, which can fuel widespread, often extreme, thunderstorms.
In southern Arizona, monsoon rains often bring half or more of our region’s annual rainfall.
Current/average monsoon totals: Monsoon rain totals can vary widely from year-to-year. In 2020, for instance, the monsoon brought less than two inches of rainfall. The next year, more than 12 inches of rain inundated the region, more than double the average.
Track the current monsoon and see historically how much rain fell during each monsoon.
U.S. Clean Water Act: A federal law that establishes the basic structure for regulating discharges of pollutants into the waters of the United States and quality standards for surface waters.
Stormwater runoff: Rain or snowmelt flowing from the land and human-built surfaces. In southern Arizona, much of the stormwater generated during the monsoon or other rainfalls flows into area washes and rivers. https://pagregion.com/sustainability/water-quality/stormwater-pollution-prevention/
Green stormwater infrastructure: Passive stormwater collection systems incorporated into roadway systems and other landscape structures to retain and use stormwater for environmental and community benefits. Green infrastructure can help minimize the amount of runoff and pollutants that enter watercourses.