Stormwater Tempe Bioswales

Clean Water Act

In response to concern over the pollution of America’s waterways, Congress passed the Clean Water Act Clean Water Act in 1972. The Clean Water Act is the primary federal law that protects our nation’s surface water bodies or waters of the United States. Polluted stormwater runoff was addressed specifically under the Clean Water Act by a two-phase program that relies on the National Pollutant Discharge Elimination System permit coverage. The two phases of the National Pollutant Discharge Elimination System stormwater program are known as Phase I and Phase II.

In 1990, the U.S. Environmental Protection Agency implemented Phase I of the NPDES Stormwater Program under the Clean Water Act. Phase I relies on National Pollutant Discharge Elimination System permit coverage to address stormwater runoff pollution from medium and large municipal separate storm sewer systems generally serving populations of 100,000 or greater, construction activities disturbing 5 acres of land or greater and 10 categories of industrial activities.

To expand the protection of water bodies and promote cleaner water, Phase II Final Rule was published in 40 Code of Federal Regulation on December 8, 1999. This rule extends the National Pollutant Discharge Elimination System permit coverage to include Small Separate Storm Sewer Systems serving urbanized areas with residential populations of at least 50,000 with an overall density of at least 1,000 people per square mile and small construction activities. Public universities are included in the Phase II Final Rule under 40 CFR 122.26 (b)(16)(iii), as “…systems similar to separate storm sewer systems in public areas such as systems at military bases, large hospitals or prison complexes…” and therefore is required to comply with Phase II Final Rule requirements. The goals of Phase II Final Rule are similar to the Phase I program, which are to reduce the discharge of pollutants to the maximum extent practicable, protect water quality and satisfy the water quality requirements of the Clean Water Act. On December 5, 2002, EPA Region 9 approved the State of Arizona’s Pollutant Discharge Elimination System Program pursuant to Section 402 of the Clean Water Act.  

The Arizona Department of Environmental Quality has primacy and administers the National Pollutant Discharge Elimination program in Arizona through the Arizona Pollutant Discharge Elimination System program. ASU submitted its original Notice of Intent application to the Arizona Department of Environmental Quality prior to the March 29, 2017 deadline. By submitting the Notice of Intent, ASU effectively applied for coverage under Permit No. AZG2016-002. ASU’s original Stormwater Management Program dated March 2003 and revisions dated July 2006, September 2008, March 2011 and June 2017 were submitted to the Arizona Department of Environmental Quality as part of the general permit requirements.  

The Arizona Department of Environmental Quality issued a new Arizona Pollutant Elimination System General Permit for Stormwater Discharges from Small Municipal Separate Sewer Systems to Protected Surface Waters effective September 30, 2021. ASU submitted a Notice of Intent application to the Arizona Department of Environmental Quality prior to the November 30, 2021 deadline. ASU received approval on November 8, 2021 for coverage under Permit AZG-2021-002.