Environmental Guidance Documents

NEPA Process Guidance for Federal Aid Projects

Water Resources

In Arizona, water resources include surface waters, riparian areas, intermittent streams and ephemeral drainages.  The Clean Water Act (CWA) of 1972 was established with the objective of restoring and preserving the chemical, physical, and biological integrity of the nation's waters by preventing point and nonpoint sources of pollution, providing assistance to publicly owned wastewater treatment plants, and maintaining the integrity of wetlands.

During the planning of a transportation project EPG assesses the potential for water resources considered jurisdictional under Section 404 of the CWA to occur within or near the project area.  As part of this determination, a jurisdictional delineation may be conducted to determine the exact boundary and types of water features (such as wetlands or drainages) present on a project site.  Please refer to the ADOT Clean Water Act Section 404/401 Guidance Manual for more details. 

EPG also assesses the potential for point source discharges of pollution, which is regulated under Section 402 of the CWA and permitted with Arizona or National Pollutant Discharge Elimination System Permits (AZPDES/NPDES). Please refer to ADOT ES Water Quality Group for more details.

After an initial field review, EPG assesses the project for compliance with the following water regulations, as applicable:

Section 404 of the CWA

NEPA requires federal agencies to consider the environmental effects of their projects, including project alternatives.  The FHWA is generally the NEPA lead federal agency for federally funded ADOT projects. An ADOT project that involves placement of fill material into a water of the US may also require a CWA Section 404 permit from the USACE.  Section 404 of the CWA establishes a program to regulate the discharge of dredged or fill material into waters of the US. The CWA defines waters of the US to include tributaries to navigable waters, interstate wetlands, wetlands that could affect interstate or foreign commerce, and wetlands adjacent to other waters of the US.  In the arid Southwest, this includes ephemeral drainages and intermittent streams. The Section 404 program is administered by the US Army Corps of Engineers (USACE) in coordination with the US Environmental Protection Agency (USEPA).  The intent of the program is that no discharge of dredged or fill material should be permitted if there is a reasonable alternative that would be less damaging to water resources.  

The USACE generally uses two permitting methodologies: Nationwide and Individual permits.  If the permit required is an Individual Permit, the USACE must determine compliance with the CWA and NEPA prior to issuing a permit.  Mitigation for unavoidable impacts to water resources may also be required. Please refer to the ADOT Clean Water Act Section 404/401 Guidance Manual for more details.

Section 401 of the CWA

Under Section 401 of the CWA, an applicant for a federal permit or license for any activity which may result in a discharge to a water body must obtain water quality certification.  This certifies that the project will comply with state or federal water quality standards, as applicable. Most certifications are issued in association with CWA Section 404 permits.  As part of the Section 404 permitting process, ADOT obtains Section 401 Water Quality Certification from the Arizona Department of Environmental Quality (ADEQ) for projects on non-tribal lands or, for projects on tribal lands, through USEPA or tribal agencies.  Please refer to the ADOT Clean Water Act Section 404/401 Guidance Manual for more details.

Section 402 of the CWA: AZPDES/NPDES

Section 402 of the CWA resulted in development of the National Pollutant Discharge Elimination System (NPDES), which is a permit program for regulating point sources of pollution.  Point sources include: industrial and commercial facilities; construction sites; new development; and municipal activities.  This system is managed by the USEPA in partnership with state environmental agencies.  In 2002, the USEPA authorized Arizona to implement and operate a NPDES program. ADEQ administers the program, which is referred to as the Arizona Pollutant Discharge Elimination System (AZPDES).  AZPDES applies to all land other than tribal in Arizona; tribal lands are regulated by USEPA. Point sources may not discharge pollutants to surface waters without implementing a NPDES or AZPDES. A Storm Water Pollution Prevention Plan (SWPPP) is required when a project will disturb more than one acre of land. Please refer to the ADOT ES Water Quality Group for more details.