WYState-AdministeredSWPPP Requirements in Wyoming
Wyoming's WYR10 Construction Stormwater General Permit covers a state dominated by energy extraction, agriculture, and exceptional natural resource values. The state sits at the headwaters of three major river systems—the Colorado (via the Green River), the Missouri (via the Yellowstone and Powder rivers), and the Columbia (via the Snake)—making Wyoming's stormwater quality decisions consequential for downstream states across a huge portion of the American West. Oil and gas extraction in the Powder River Basin (northeastern Wyoming) and the Green River/Overthrust Belt (southwestern Wyoming) creates unique stormwater challenges. While E&P production activities hold separate permits, the construction phase of well pads, access roads, pipelines, and processing facilities falls under WYR10. These sites often involve disturbing multiple disconnected acres across a large landscape, and tracking compliance across dozens of simultaneous construction projects in remote terrain is a persistent challenge for both operators and WY DEQ. Wyoming's climate extremes define the construction stormwater challenge more than any other factor. Temperatures range from below -40°F in winter to over 100°F in summer. Winds regularly exceed 50 mph on the open plains, creating severe wind erosion from disturbed sites. The construction season in most of Wyoming is only 5-6 months (May through October), compressing project timelines and creating end-of-season BMP deployment rushes. The Wind River Range and Bighorn Mountains generate significant snowmelt runoff in spring that can overwhelm undersized sediment controls on lower-elevation projects.
Wyoming SWPPP Key Facts
- ✓Wyoming sits at the headwaters of three continental river systems (Colorado, Missouri, Columbia)—construction stormwater quality has regional downstream implications
- ✓Oil and gas construction (well pads, access roads, pipelines) falls under WYR10 during construction phase—the Powder River Basin is an active enforcement area
- ✓Wyoming's construction season is approximately 5-6 months (May-October) due to extreme winter temperatures
- ✓Wind River Reservation has tribal sovereign authority—state WYR10 permit does not apply within reservation boundaries; EPA CGP applies instead
- ✓Wyoming winds regularly exceed 50 mph on the plains, making wind erosion a primary BMP challenge on flat disturbed sites
- ✓Yellowstone and Grand Teton National Park surroundings (Teton County) have enhanced scrutiny due to tourism economy and exceptional natural values
- ✓No Wyoming-specific vegetation mix requirements, but native shortgrass prairie species (buffalo grass, blue grama) are strongly preferred for permanent stabilization
- ✓NOI fee is $500 plus $500/year with a $100 NOT fee—higher than many Northern Plains states reflecting energy-sector activity funding
Administering Agency
- Agency
- Wyoming Department of Environmental Quality, Water Quality Division (WY DEQ)
- Phone
- 307-777-7781
- wqd@wyo.gov
- Website
- WY DEQ Stormwater Program
Permit Details
- Permit Name
- Wyoming Pollutant Discharge Elimination System Construction Stormwater General Permit
- Permit Number
- WYR10
- Effective Date
- 2018-09-01
SWPPP Thresholds & Triggers
- Acreage Threshold
- 1 acre of land disturbance, or less than 1 acre if part of a larger common plan of development exceeding 1 acre
Oil and gas exploration and production activities have separate permit requirements (WYR001 for produced water) but construction at E&P sites falls under WYR10 during the construction phase. Yellowstone and Wind River headwaters have enhanced sensitivity designations. Wind River Reservation has tribal sovereign authority over stormwater within the reservation boundary.
Inspection Requirements
- Inspection Frequency
- At least every 14 days and within 24 hours of a qualifying storm event of 0.5 inch or more in a 24-hour period. For oil and gas construction sites, inspections may be more frequent due to facility permit conditions.
- Rain Event Threshold
- 0.5 inch in a 24-hour period; snowmelt producing visible surface runoff is a qualifying event
- Certified Inspector
- Required by state
- Accepted Certifications
- CPESC, CESSWI, CISEC, Wyoming DEQ-approved training programs
Wyoming's construction season is severely limited by climate—Cheyenne has 36 days per year below 0°F, and much of Wyoming's highland terrain is impassable or frozen from November through April. Contractors must complete stabilization or winter BMP deployment before first freeze, typically mid-October. The Powder River Basin oil patch in northeastern Wyoming has continuous construction activity that tests permittee compliance year-round.
Penalties & Enforcement
- Max Civil Penalty (Per Day)
- $25,000 per day per violation under Wyoming Environmental Quality Act
- Criminal Penalties
- Up to $25,000/day and/or up to one year imprisonment for willful violations
WY DEQ enforcement is concentrated in the Powder River Basin (Gillette, Casper) due to oil and gas construction activity and in the Jackson Hole/Teton area due to sensitive alpine watershed conditions and high-profile development projects.
Permit Fees
- NOI Filing Fee
- $500 (Stormwater Authorization Request fee)
- Annual Fee
- $500 per year
- NOT Filing Fee
- $100 (Not of Termination fee)
- Other Fees
- Oil and gas facility construction sites may face additional WY DEQ permit coordination fees
How Wyoming Differs from Federal Requirements
- ⚠Wyoming's WYR10 does not apply within the Wind River Indian Reservation—a significant tribal sovereignty carve-out requiring contractors to use the federal CGP for reservation projects
- ⚠Oil and gas construction creates dual-permit situations unique to Wyoming's energy extraction economy—E&P operators must track both WYR10 and production permits simultaneously
- ⚠WY DEQ fee structure ($500 NOI + $500/year) is higher than some neighboring states but does not include the complex tiered systems of Oregon or California
- ⚠Wyoming's permit period is structured differently from the 5-year federal CGP cycle—WYR10 issuance dates and renewal timelines follow state administrative schedules
- ⚠Federal CGP's turbidity benchmarks for impaired water body discharges apply if a site uses the federal permit (reservation land)—Wyoming state permit has different benchmark language
SWPPP Tips for Wyoming
- ➤For oil and gas construction sites, coordinate with your E&P operator's compliance team early—they'll have site-specific permit conditions that must be layered with WYR10 requirements.
- ➤Install wind erosion controls (gravel mulch, dust suppressants, vegetative windbreaks) before any soil disturbance in windy Wyoming locations. A 50 mph wind event can strip bare soil faster than a rainstorm.
- ➤Plan for your fall winterization date as October 1 in northern/high elevation Wyoming and October 15 in the lower Powder River Basin. Wyoming DEQ inspectors look hard at sites after the first freeze for inadequate BMP deployment.
- ➤Jackson Hole and Teton County projects face local land use restrictions that are stricter than state stormwater rules. Engage Teton County planning early and expect elevated scrutiny on any discharge pathway toward the Snake River.
- ➤For sites on or adjacent to Wind River Indian Reservation, contact EPA Region 8 (Denver) directly—the state permit does not apply and you'll need a federal CGP authorization.
- ➤Size sediment basins for the Wind River or Bighorn Mountain snowmelt contribution, not just individual storm events. Spring snowmelt can deliver weeks of sustained flow far exceeding any single rain event.
Wyoming SWPPP FAQs
Does WYR10 apply to construction at oil and gas well pads and pipeline corridors?+
Yes. While E&P operations (drilling, production, storage) have separate Wyoming WYPDES permits, the construction and reclamation phases of oil and gas facilities fall under WYR10 when they disturb 1 acre or more. Contractors on oil patch projects must obtain WYR10 authorization before breaking ground and maintain a compliant SWPPP throughout construction.
What is the stormwater permit situation on the Wind River Indian Reservation?+
The Wind River Indian Reservation (Eastern Shoshone and Northern Arapaho Tribes) has tribal sovereign authority over environmental programs within the reservation. Wyoming's WYR10 permit does not apply within the reservation boundary. Construction projects there require authorization under the EPA federal CGP (administered by EPA Region 8, Denver). Contractors should confirm the exact project boundary relative to the reservation before applying for permits.
How does Wyoming's extreme wind affect SWPPP requirements?+
Wyoming's permit requires BMPs to control stormwater discharge, but in practice, wind-blown sediment from construction sites can deposit into adjacent drainages and become a discharge pathway. WY DEQ expects SWPPP to address wind erosion in areas with prevailing high winds. Gravel mulch, surface tackifiers, and temporary windbreaks (straw bales, construction fencing) are common BMPs for wind-erosion control on Wyoming plains sites.
When is the Wyoming construction stormwater season?+
Wyoming's effective construction season is approximately May through October in valley and plains locations, and June through September at higher elevations. WYR10 permit requirements apply year-round regardless of season, but BMP installation and stabilization activities are constrained by frozen ground. Winter-protection plans submitted before freeze-up can allow sites to remain authorized during dormant periods.
How do I file an NOI for construction in Wyoming?+
Submit your Stormwater Authorization Request through WY DEQ's online permitting system before any land disturbance begins. The fee is $500, with a $500 annual renewal. A $100 Notice of Termination fee applies at project completion. WY DEQ typically processes requests within 10 business days. For oil and gas construction sites, additional coordination with your E&P operator's compliance team may be needed.
What are the penalties for SWPPP violations in Wyoming?+
WY DEQ can assess civil penalties up to $25,000 per day per violation under the Wyoming Environmental Quality Act. Willful violations can trigger criminal penalties up to $25,000/day and up to one year imprisonment. Enforcement is concentrated in the Powder River Basin (energy sector) and Teton County (high-profile development near Grand Teton and Yellowstone National Parks).
Find a SWPPP Consultant in Wyoming
Tell us about your project and we'll connect you with a qualified environmental consultant — free, no obligation.