WAPA » Regions » DSW » Environmental review--NEPA

Environment Review - NEPA

About DSW Environmental Resources

DSW operates and maintains more than 40 substations and 3,100 miles (4,950 kilometers) of transmission lines across Arizona, southeast California and southern Nevada to keep the system running reliably. The region has three main topographical areas:  (1) a high plateau averaging between 5,000 and 7,000 feet in elevation in the northeast;  (2) a mountainous region oriented southeast to northwest with maximum elevations between 9,000 and 12,000 feet about mean sea level; and (3) low mountain ranges and desert valleys in the southwestern portion of the state. The highest elevation area of DSW facilities is in Flagstaff, Arizona at approximately 7000 feet.  The lowest elevation area of DSW facilities is in Yuma, AZ at approximately 140 feet.   There are a total of 117 federally listed species in the DSW Region.  48 of these Federally Listed Species are in areas where our facilities occur.  Seven of these are the most active on a day-to-day basis:  Lesser long-nosed bat, Mexican spotted owl; Mojave desert tortoise; Pima pineapple cactus; Southwestern willow flycatcher, Yellow-billed cuckoo; and Yuma clapper rail.   The DSW Region is known for having a rich cultural history.  The Native American tribes have long inhabited the southwest United States. Their roots here date back some 15,000 years, when the first Paleo Indians lived by hunting and gathering in the arid and dangerous terrain.  In central and southern Arizona, the Hohokam built a society based on agriculture supported by a vast network of canals, which drew water from the Salt, Gila and other rivers. With their resources of farmed food and a large population, the Hohokam constructed numerous villages such as can be seen now in parks such as Pueblo Grande in Phoenix, Mesa Grande in Mesa, and Casa Grande in Coolidge. Further north, the Anasazi built large pueblos, many constructed in the sides of cliffs for protection, such as at Montezuma’s Castle in Camp Verde and Navajo National Monument on the Navajo Reservation.  Whether it relates to ancient Indian cultures, intrepid Spanish missionaries, ambitious American pioneers, or modern families looking for opportunities to build their livelihoods, Arizona is a historic land. DSW projects frequently involve the need to address impacts to cultural resources.  Working with tribes, AZ State Historic Preservation Office (SHPO) and others, we do our part in environmental stewardship.  The DSW Region includes ample federal or public lands managed by U.S. Department of Interior, Bureau of Land Management, National Park Service, Bureau of Indian Affairs and Bureau of Reclamation; and the U.S. Department of Agriculture, Forest Service.  Coordinating with the federal land managers on carrying out our mission has been an important focus in the environmental review for the DSW region.

​​Environmental Review - NEPA​

The Environmental Team at DSW primarily works on projects that require Categorical Exclusions and Environmental Assessments.  For actions that may have significant impacts or consequences to the environment or human health, DSW works in conjunction with Natural Resources staff at the Headquarters office in Lakewood, CO, to prepare Environmental Impact Statements.​  In order to promote transparency and openness, the various types of environmental documents are posted below:

Environmental Impact Statements, EIS

Environmental Assessments, EA​

Finding of No Significant Impact

Programmatic Agreements




DSW’s Facilities Historic Context Statement

Categorical Exclusions—CX

​Operation and Maintenance Program Wide









  • Amargosa Substation (Conduit and Storage Pad Installation) (6-3-14)
  • Amargosa Substation (Control Building Repairs) (9-10-14)
  • Blythe-Knob 161-kV Transmission Line, Structure Maintenance Project (1-21-14)
  • Blythe-Knob 161-kV Transmission Line, Cross Arm Replacements (3-6-14)
  • Bouse Hills Pumping Plant to Harcuvar 115-kV Transmission Line, Inset Structure Installation (8-27-14)
  • Cable Trenching in the Gila Substation (1-13-14)
  • Commercial Cell Antenna Maintenance at DSW Facilities (12-18-14)
  • Coolidge Substation Outgrant to Southwest Gas for Pipeline (2-18-14)
  • Crossman Peak Communication Site Lease and Equipment Upgrades at 5 Facilities (6-2-14)
  • Davis Dam Maintenance Building installation at the old Davis Dam 69-kV West Switchyard (6-30-14)
  • ED2-ED4 Transmission Line Rebuild Project (7-10-14)
  • Electrical District 2 to Saguaro #2 115-kV Transmission Line, Marker Ball Installation at Structure 26-10 (1-9-14)
  • Electrical District 2 to Saguaro #2 Transmission Line Geologic Investigation Project (3-14-14)
  • ED5-SGR2 NERC Mitigation (9-11-14)
  • Flagstaff to Pinnacle Peak #1 and #2 345-kV Transmission Lines Insulator Replacements (7-1-14)
  • Flagstaff Pinnacle Peak #1&2 Transmission Lines – Slid Static Damper Repair at Structures 134/3 & 139/2 (6-11-14)
  • GCS 345kV-SF^ Breaker (3396) and Concrete Pad Installation (2-6-14)
  • Gila Knob Transmission Line - Anchor Repair at Structure 4/7 (11-13-14)
  • Gila-Kofa 161-kV Transmission Line, Emergency Erosion Repair at Structure 102-6 (7-16-14)
  • Gila Substation Geotechnical Study (8-6-14)
  • Henderson 230kV Switchyard (Erosion Control) (2-6-14)
  • Henderson-Mead #1 230-kV Transmission Line Access Road Maintenance (7-22-14)
  • Humboldt Mountain Communication Facility – Asbestos and Lead-based Paint Testing (6-19-14)
  • Humboldt Mountain Communication Facility – Demolition (10-29-2014)
  • Liberty Parker #2 Transmission Line - Erosion Repair at Structure 53/1 (6-9-14))
  • Liberty Substation - Vegetation Management (4-1-14)
  • Liberty-Westwing 230-kV Transmission Line Insulator Replacement (6-5-14)
  • Lone Butte Substation Erosion Repairs (9-11-14)
  • Mead Administrative Building Demolition(3-26-14)
  • Mead-Liberty 345-kV Transmission Line Access Road and Maintenance and Localized Vegetation Management Project (8-27-14)
  • Mead Substation Access Road Repairs (11-7-2014)
  • Mead Substation Service Building Repairs (8-28-2014)
  • Metal Mountain Communications Site _ Emergency Air Conditioner Replacement (7-3-2014)
  • NERC Mitigation Actions Along Three Transmission Lines (6-5-2014)
  • Prescott-Pinnacle Peak 230-kV Tranmission Line Access Road Maintenance and Localized Vegetation Management Project (9-9-2014)
  • Prescott Pinnacle Peak Structure 195/2 – Commercial Cell Antenna Maintenance (10-2-14)
  • Prescott Pinnacle Peak Structure 213/4 - Commercial Cell Antenna Maintenance (10-23-14)
  • Prescott Peacock Transmission Line – Insulator Repair at 3 Structures (7-31-14)
  • Saguaro-Tucson 115-kV Transmission Line Cross Arm Replacements(2-11-14)
  • Tucson-Apache 115-kV Transmission Line, Access Road Repairs Mile 14 to 20 (11-14-14)
  • Tucson Substation - Asbestos Abatement (6-3-14)
  • Valley Farms Substation - Emergency Installation of Concrete Pad for Western's Communication Tower (4-1-14)
  • Valley Farms to Oracle 115-kV Transmission Line, Guy Anchor Repairs at Structure 6-8 (11-24-14)
  • Wood Pole Testing along 20 Transmission Lines (4-17-2014)


  • Adams Tap MOI and Control Building Replacement (9-11-13)
  • Casa Grande Substation, CAG 262 Breaker Replacement (4-4-13)
  • COLORA - Cross-Arm Replacement, Structure Nos. 12-3, 12-6 (9-23-13)
  • Davis Dam to Kingman Tap 69-kV Transmission Line, Overhead Optical Power Ground Wire Installation (5-16-13)
  • Davis Dam to MEC Kingman Tap 69-kV Transmission Line Rebuild (3-20-13)
  • Davis-Parker 230kV Transmission Line - Marker Ball(s) Replacement (12-17-13)
  • DSWR - Bi-Annual "Live Line" Maintenance Training (10-08-13)
  • Electrical District 2 to Saguaro #2 115-kV Transmission Line Access Road Maintenance between Structure 26/8 and 26/9 (5-20-13)
  • Gila Substation Emergency Current Transformer Replacement (4-26-13)
  • 3 Yuma Area Transmission Lines Emergency Storm Damage Repairs (8-26-2013)
  • GCS Switchyard - 230-kV Wavetrap Removal - TZ9A2 on the Navajo Line (6-21-13)
  • Gila Knob Transmission Line Crossarm Replacement at Structure 18/3 (06-03-2013)
  • Gila Knob Transmission Line Hot Crossarm Changeout Training (12-16-2013)
  • Gila-Wellton Mohawk Transmission Line Maintenance (1-3-13)
  • Glen Canyon Substation Stage 09- 50MVA 230/69kV Transformer Addition (7-2-13)
  • Glen Canyon to Flagstaff #2 345-kV Transmission Line, Access Road Maintenance from Structure 45/4 to 46/1 (8-8-13)
  • Henderson Mead #2 Erosion Control Project Near Structure 2/4 (9-11-13)
  • 40 Arizona Substations Herbicide Application (7-1-13)
  • 4 Southern California Substations Herbicide Application (7-1-13)
  • 1 Gila River Indian Community Substation Herbicide Application (7-1-13)
  • 2 Navajo Nation Substations Herbicide Application (7-1-13)
  • 4 Southern Nevada Substations Herbicide Application (7-1-13)
  • 36 Substations in AZ & CA Herbicide Application during FY2013 (4-19-13)
  • Lone Butte Substation located on the Gila River Indian Community, AZ during FY2013 Herbicide Application (4-24-13)
  • Hoover-Mead #1 and #5 230-kV and Mead-Marketplace 500-kV Transmission Lines Facilities Ratings Project (3-20-13)
  • Hoover-Mead #8 230-kV Transmission Line Insulator Repair Project (3-11-13)
  • Oracle Electrical Substation Installation of Cattle Guard (5-9-13)
  • Liberty-Parker Dam #2 230-kV Transmission Line, Optical Power Ground Wire Repair (08-22-2013)
  • LIBPAD-1 230 kV Transmission Line "Live Line" Maintenance Training at Structure 112-4 (10-25-2013)
  • Liberty Substation Transformer Replacement Project, Maricopa County, Arizona (06-06-2013)
  • Electrical District 5 Substation Project Material Source Site (2-28-13)
  • Mead KU2A Emergency Bushing Replacement (7-2-13)
  • Nogales Substation Temporary Laydown Yard (3/28/13)
  • Oracle Substation - Breaker Support Work (10-30-13)
  • Oracle to Tucson 115-kV Transmission Line, Cross Arm Replacements at Structures 2/5 and 7/3 (5-2-13)
  • Parker Dam to Gila 161-kV Transmission Line, Cross Arm Replacement at Structure 0/7 (7-22-13)
  • Parker Dam to Headgate Rock and Parker Dam to Bouse 161-kV Transmission Lines, Cross Arm Repairs and Helicopter Staging Areas Project (2-19-13)
  • Parker-Gila 161-kV Transmission Line Maintenance Project, Structure 92/1 to 94/9 (6-5-13)
  • Parker-Gila 161-kV Transmission Line - Structure 109-8 Relocation (12-18-13)
  • Parker Substation 161-kV 2013 Breaker Replacement (5-17-13)
  • 44 Substations in Arizona, California, and Nevada Pest Control within Buildings (6-6-13)
  • Phoenix to Lone Butte 230-kV Transmission Line, Bird Diverter Installation (4-8-13)
  • PHX-LOB and LIB-LOB 230-kV double-circuit - replace insulators at Structure No. 28-2 with NCI type polymers (8-12-13)
  • Pinnacle Peak - Rogers 230-kV Double Inset Structure #5/1a Installation (6-28-13)
  • Prescott to Peacock 230-kV Transmission Line Hazard Tree Removal between Structures 54/1 and 107/1 (11-22-2013)
  • Protection and Communication Facilities Maintenance (11-8-13)
  • Oracle Breakers 562 and 762 Removal and Replacement along with Associated Disconnects (7-2-13)
  • Saguaro-Tucson 115-kV Transmission Line Road Maintenance and Brushwork (4-30-13)
  • Saguaro-Tucson 115-kV Transmission Line, Structure Replacement at 10-4 (12-3-13)
  • Tucson Apache Emergency Structure Stabilization Project (9-6-13)
  • Tucson to Apache 115-kV Transmission Line Wood Pole Replacement Project (2-28-13)


Page Last Updated: 9/8/2020 10:11 AM