CATEGORICAL EXCLUSION DETERMINATION - Town of Encampment, Lagoon Improvement Project

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Wyoming Department of Environmental Quality


For the Town of Encampment, Lagoon Improvement Project

Carbon County, Wyoming

The Department of Environmental Quality/Water Quality Division (DEQ) has conducted a review of the proposed Lagoon Improvements Project in accordance with EPA and State of Wyoming procedures for implementing the State Environmental Review Process. DEQ has determined that this project is eligible for a categorical exclusion. Accordingly, DEQ is exempting the project from further substantive environmental review requirements under the State Environmental Review Process. Neither an Environmental Assessment/Finding of No Significant Impact nor an Environmental Impact Statement/Record of Decision will be required for the proposed action. The following is a brief description of the situation and the proposed action and a brief statement of how the action meets the criteria for a categorical exclusion.

This project includes extensive improvements to the headworks, outlet works, and lagoon cells in order to meet quality compliance requirements currently not being met by the Town of Encampment. Specifically, periodic discharge permit limits for BOD and pH are frequently out of compliance due to inadequate treatment. It is anticipated that improvements to the wastewater treatment facility under this project will include installation of influent screening equipment, installation of aeration equipment, the possible installation of pond cover(s), and the installation of influent and effluent metering equipment as necessary to meet reporting and permit requirements.

The estimated cost for the Lagoon Improvement Project is $1,499,790. The Town of Encampment has requested a Wyoming Clean Water State Revolving Loan Fund in the amount of $500,000 with principal forgiveness of $375,000. This loan was conditionally approved on April 4, 2019. The reserves from the 2018 specific purpose tax and revenues from the 2019 specific purpose tax will fund the remaining balance of the anticipated project costs and the loan repayment. The Town does not anticipate increasing user rates as a result of this project.

The Town of Encampment is aware of and accepts the fact that they will be responsible for any required mitigative actions associated with and including storm water runoff, erosion control, archeological/historic artifacts, and air quality concerns. These will be part of the standard State Revolving Funds Program contract conditions. No significant environmental impacts that require mitigation have been identified.

DEQ is granting an exclusion because the project includes modifications to an existing system and is being constructed in previously disturbed ground, specifically ground previously disturbed by the construction of the existing lagoon cells, sewer lines, underdrains, and access roads. DEQ has determined that exempting the proposed project from further review under the State Environmental Review Process will not result in adverse impacts to the population or the area of Encampment, Carbon County, Wyoming.

The documentation to support this decision will be on file in the Department of Environmental Quality Cheyenne Office and is available for public scrutiny upon request. Comments concerning this decision may be addressed to Stan Miller, SRF Project Engineer, Department of Environmental Quality, 200 W. 17th Street, Suite 200, Cheyenne, WY 82002, TEL: (307) 777-6371, FAX: (307) 635-1784, email:

Publish Date: May 8, 2019