The Verde River watershed provides water to more than three million Arizona residents from Prescott to Sedona to Phoenix. The watershed supports 94 species of mammals, most of which use the river at some point in their lifecycle, and some of which, such as otters and beavers, spend their entire lives in the river.
It is important to clearly identify the risks so that we can address them and focus on implementing solutions. The threats may seem simple - increases in water demand and on-going drought - but solving them is complicated. We need good data to inform long term plans for water quality and quantity, affordable housing, available jobs, sustainable recreation, and investment in restoration actions.
Increases and changes in water use without water certainty
Most drinking water in the Verde Watershed comes from groundwater sources. Groundwater is the water found below the surface in the cracks and spaces in soil, sand, and rock. It is stored in, and moves slowly through, geologic formations called aquifers. Rules governing groundwater in Arizona differ based on whether the land is inside or outside of an Active Management Area (AMA). There are two AMAs in the Verde watershed: the Prescott AMA and the Phoenix AMA. Outside of AMAs, there is little regulation of groundwater. To learn more about AMAs and how they are managed visit: https://new.azwater.gov/ama.
Another important source of water in the Verde Watershed is surface water, which flows within a stream or river channel. In Arizona, water that is immediately adjacent to and under the river channel and will flow into the river can be regulated as surface water. Surface water in the Verde Valley is used to irrigate farms, gardens, and lawns where the landowners have historic rights to use water.
Adjudication is the judicial proceeding to determine the aspects of water rights in Arizona as they relate to each other. The Verde River is part of the Gila River System and Source Adjudication initiated in the 1970s. As this adjudication process awaits completion, it remains unclear who has a right to how much water and where it can be used. As a result, we have uncertainty among surface water users, resulting in even more uncertainty for nature.
Changes in land use
Changes in land use happen in many ways. On private lands, what was once used for ranching or farming may become housing. We need available and affordable housing in our communities and so the way in which land is developed matters. Traditionally, development outside of a municipality allows for a two-acre lot with a septic system and a private well. This creates dispersed water use and potential for water quality impacts related to septic tanks. Higher density development may increase the number of impervious surfaces – decreasing the amount of natural recharge that occurs. High density development allows for the protection of open space, shared water and sewer services, and other community amenities.
However, integrated land and water planning can address these challenges. Changes in land use are an opportunity for a conversation about how to ensure quality of life for current and future residents while maintaining and enhancing the environment.
Land management
On public lands, the long-term impacts of drought, climate change, roads, other access and grazing practices have altered the landscape. The result can be increased erosion and run off, leaving gullies that range from small to large. Implementing projects requires funding and regulatory review and approval.
Sustainable recreation is a critical part of our community goals and yet achieving that requires coordination, education and investment for diverse stakeholders. Balancing different user groups needs with ecological needs requires careful planning and on-going dialog.
Invasive plants
Invasive plants, such as Tamarisk (also known as salt-cedar), Arundo, Russian Olive, and Tree of Heaven can have devastating impacts on a river and the birds and other wildlife that live along the river. Heavy infestations can cause the river to cut deeper into surrounding soils and lose its natural character. These plants replace other native species and do not provide the same nesting and nutrition to native birds and animals. In many cases these species grow so tightly together that access to the river can be difficult or impossible for humans and many animals. Once this dominate, single species forest replaces natural forests it can become a serious fire risk if weakened by insects or disease.
Rivers throughout the Southwest have fallen prey to these pest plants. While local coalitions have thus far kept invasive plants at bay over most of the watershed, vigilant work is required to keep them from destroying the riverside forests we love.