In a rule published July 2, 2002, EPA found the Arizona Department of Environmental Quality’s "Plan for Attainment of the 24-Hour PM10 Standard – Maricopa County PM10 Nonattainment Area" (May 1997), inadequate to achieve attainment of the 24-hour National Ambient Air Quality Standards for particulate matter 10 microns or fewer in aerodynamic diameter (PM10) at the Salt River monitoring site. The 1997 ADEQ SIP revision included attainment and Reasonable Further Progress demonstrations for the 24-hour NAAQS at the Salt River air quality monitoring site of the Maricopa County PM10 Serious Nonattainment Area, as well as at three other monitoring sites in the Phoenix area, - the Maryvale, Gilbert, and West Chandler sites. On August 4, 1997, EPA approved ADEQ’s attainment and RFP demonstrations for the Salt River monitoring area, which showed that the 24-hour PM10 NAAQS would reach attainment in the area by May 1998. Due to continuing violations of the 24-hour PM10 NAAQS at the Salt River air quality monitoring site since May 1998, EPA subsequently required Arizona to submit a revision to correct SIP inadequacies. This document consists of Arizona’s revisions to the state implementation plan for the Maricopa County PM10 Serious Nonattainment Area as described by EPA in its Federal Register notice of disapproval.

The Arizona Legislature established ADEQ as the state’s environmental regulatory agency under the Environmental Quality Act of 1986. Its mission is to protect and enhance public health and the environment in Arizona. The department achieves this mission by administering our state’s environmental laws and delegated federal programs to prevent pollution of our air, water and land, and to clean up such pollution when it occurs. The department’s organizational structure is composed of four programmatic divisions that fulfill our environmental protection mission in the areas of air quality, water quality, waste programs, and tank programs.

The Upper Hassayampa groundwater basin covers approximately 787 square miles within Maricopa and Yavapai counties and is located about 60 miles northwest of Phoenix. The basin is characterized by mid-elevation mountains and had an estimated population of 10,479 in 2000. The largest population center is the Town of Wickenburg. Other communities include Congress and Groom Creek. Low-intensity livestock grazing is the predominant land use and most ranches have limited acreages of irrigated pasture to raise additional animal feed. There are no surface water diversions or impoundments besides small stock ponds within the basin. Groundwater is the only source for public water supply, domestic, irrigation and industrial purposes. Public water supply uses the most groundwater in the basin.

The Aravaipa Canyon groundwater basin covers approximately 517 square miles in southeastern Arizona within Graham and Pinal counties. Largely undeveloped, the remote basin has an estimated 135 residents and includes the community of Klondyke. Low-intensity livestock grazing is the predominant land use although there are some irrigated fields and orchards along Aravaipa Creek. Historic mining activity resulted in the creation of the Klondyke Tailings Water Quality Assurance Revolving Fund site in 1998. Groundwater is used for all domestic purposes within the basin as well as most irrigation and stock water supplies. Irrigation uses the most groundwater in the basin.

An update to the Flagstaff Regional Plan 2030 (FRP30), to bring its Road Network Illustration (Map 25) into compliance with Arizona Revised Statute requirements and to resolve inconsistencies between Map 25 and parts of the Flagstaff City Code. This update does not alter the intent of FRP30; it is only concerned with correcting errors, removing legal vulnerability, and improving the readability of FRP30.