Yavapai County is located in the central portion of the State of Arizona. The Prescott Urbanized area is located in the central portion of Yavapai County. Prescott Valley and Prescott have jurisdiction over 87% of the land area within the urbanized area boundary. The unincorporated County areas consist of residential developments (99%) with a few scattered commercial (1%) frontages along State Route 69 and Iron Springs Road. These commercial properties are in the areas of Castle Canyon Mesa, Diamond Valley, and Forbing Park (see Attachment 1).
The storm drain systems in these unincorporated areas compose of culverts and roadside drainage ditches. Stormwater flow that exits the roadside drainage ditch system generally follows the natural topography and within natural swales, drainage ways, and small watercourses.
Most of the County areas are located within what is commonly referred to as the Prescott Basin. Major watercourses are Willow Creek, Miller Creek, Aspen Creek, Granite Creek, Bannon Creek, Government Canyon, and Slaughter House Gulch. These receiving watercourses all flow into Granite Creek, which eventually flows into the Verde River near Paulden, Arizona. The remainder of the County areas flow into the Agua Fria River or Lynx Creek. None of these waters are listed on the 303d list of impaired waters.
Six Minimum Control Measures
Yavapai County is proposing to develop, implement and enforce a stormwater management program by December 19, 2007, to reduce pollutants discharged from municipally owned MS4s to the maximum extent practicable, given available financing and manpower, in order to protect water quality. To achieve this goal, Yavapai County has developed a five-year program consisting of the six required control measures. This program will result in the identification of Best Management Practices (BMPs) and measurable goals for the BMPs. Complete implementation of the County’s StormWater Management Program is expected to be an ongoing process, and outlined in the following pages.