Comment Period: September 9, 2021 to October 9, 2021
SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a permit application for the discharge of dredged and/or fill material in approximately 1.5 acres of waters of the United States to rehabilitate the Mountain Dell dam. This notice is to inform interested parties of the proposed activity and to solicit comments.
AUTHORITY: This application is being evaluated under Section 404 of the Clean Water Act for the discharge of dredged or fill material in waters of the United States.
APPLICANT: Salt Lake City Department of Public Utilities
c/o Mr. Bernard Mo
1530 South West Temple
Salt Lake City, UT 84115
LOCATION: The approximately 1.5-acre project site is located at Mountain Dell reservoir, an existing impoundment of Parley’s Creek adjacent to Interstate 80 in Salt Lake County, Utah, Latitude 40.751927°, Longitude -111.720244°, and can be seen on the Mountain Dell USGS Topographic Quadrangle.
PROJECT DESCRIPTION: The applicant is proposing to discharge dredged and/or fill material into 1.50 acres of waters of the United States (WOTUS) to remove sediment at the upstream face of the dam to replace a leaking lower outlet, and to install a liner to waterproof the lower part of the upstream face of the dam. In addition, construction of an earthen cofferdam upstream is proposed to control water during these activities (Enclosure 2). Based on the available information, the overall project purpose is to rehabilitate a critical dam structure. The applicant believes there is a need to rehabilitate the dam structure since the dam pipes and valves are 60 to 100 years old and towards the end of their service life.
Environmental Setting: Mountain Dell reservoir is located 10 miles (16 km) east of Salt Lake City in northeast Salt Lake County, Utah. At an elevation of 5500 feet, the 81-acre reservoir is an artificial impoundment of Parley’s creek, a perennial stream. Used for potable water for Salt Lake County, flood control, and recreation, the reservoir is located adjacent to Interstate 80 at the foot of the Wasatch Mountain range. The adjacent landscape is composed of native plant life with some ephemeral streams and is generally undeveloped. There are few, if any, residential subdivisions or commercial properties with the exception of the Mountain Dell golf course, a publicly owned recreation facility that is located 1.5 miles upstream from the dam.
Alternatives. The applicant has provided information concerning project alternatives. Additional information on the alternatives may be available from the applicant or their agent.
The no action alternative was not considered viable by the applicant. The dam is a supplier of potable water and a flood control facility.The lower outlet to the dam is leaking and if not replaced, the structure would be placed on storage restriction by the Division of Natural Resources, Dam Safety Program.Water could not be impounded, reducing flood control abilities for Salt Lake City.It would also adversely affect the treatment of public drinking water.
The applicant has provided information concerning four alternatives, including the preferred alternative of excavating soil at the upstream face of the dam to replace the lower outlet and waterproof the lower part of the upstream face of the dam. The construction of an earthen cofferdam upstream is proposed to control water during these activities. The applicant states the only practicable alternative is the preferred alternative as it provides the needed repairs with the least impact to the adjacent environment, water quality and public safety. In addition, the earthen cofferdam would become a permanent rather than a temporary structure.
The applicant has indicated that the offsite alternative is not practicable because additional construction would be required to expand the access road, the ground available for required dewatering of the soil would be on a sensitive adjacent environment, and the volume of material to be removed would require a significant presence of large dump trucks which could affect public safety.
Two on-site alternatives were presented that included disposing of soils in adjacent uplands or constructing a sheetpile cofferdam. The applicant indicates that filling adjacent uplands rather than filling within WOTUS would negatively affect the adjacent native plant environment. A sheetpile cofferdam would be a temporary structure and therefore unavailable for future dam maintenance or repairs. Furthermore, a sheetpile dam would require reservoir water to be maintained during construction which would negatively affect water quality and would also require significantly more excavation.
Other alternatives may develop during the review process for this permit application. All reasonable project alternatives, in particular those which may be less damaging to the aquatic environment, will be considered.
Mitigation. The Corps requires that applicants consider and use all reasonable and practical measures to avoid and minimize impacts to aquatic resources. If the applicant is unable to avoid or minimize all impacts, the Corps may require compensatory mitigation.
OTHER GOVERNMENTAL AUTHORIZATIONS: Water quality certification or a waiver, as required under Section 401 of the Clean Water Act from the Utah Department of Environmental Quality, Division of Water Quality, is required for this project. The applicant has indicated they have applied for certification.
HISTORIC PROPERTIES: Based on available information, no cultural resources were identified within the project's area of potential effect. However, the dam itself may be an historic property as it was originally constructed in 1917. The Corps will initiate consultation with the State Historic Preservation Officer under Section 106 of the National Historic Preservation Act as appropriate.
ENDANGERED SPECIES: The project would not affect any Federally listed threatened or endangered species or their critical habitat that are protected by the Endangered Species Act.
ESSENTIAL FISH HABITAT: The proposed project would not adversely affect Essential Fish Habitat (EFH) as defined in the Magnuson-Stevens Fishery Conservation and Management Act.
EVALUATION FACTORS: The decision whether to issue a permit will be based on an evaluation of the probable impacts, including cumulative impacts, of the described activity on the public interest. That decision will reflect the national concern for both protection and utilization of important resources. The benefit, which reasonably may be expected to accrue from the described activity, must be balanced against its reasonably foreseeable detriments. All factors which may be relevant to the described activity will be considered, including the cumulative effects thereof; among those are conservation, economics, aesthetics, general environmental concerns, wetlands, historic properties, fish and wildlife values, flood hazards, floodplain values, land use, navigation, shoreline erosion and accretion, recreation, water supply and conservation, water quality, energy needs, safety, food and fiber production, mineral needs, consideration of property ownership and, in general, the needs and welfare of the people. The activity's impact on the public interest will include application of the Section 404(b)(1) guidelines promulgated by the Administrator, Environmental Protection Agency (40 CFR Part 230).
The Corps is soliciting comments from the public, Federal, State, and local agencies and officials, Indian tribes, and other interested parties in order to consider and evaluate the impacts of this proposed activity. Any comments received will be considered by the Corps to determine whether to issue, modify, condition, or deny a permit for this proposal. To make this decision, comments are used to assess impacts on endangered species, historic properties, water quality, general environmental effects, and other public interest factors listed above. Comments are used in the preparation of an Environmental Assessment and/or an Environmental Impact Statement pursuant to the National Environmental Policy Act. Comments are also used to determine the need for a public hearing and to determine the overall public interest of the proposed activity.
SUBMITTING COMMENTS: Written comments, referencing Public Notice SPK-2021-00470 must be submitted to the office listed below on or before October 9, 2021.
Nicole Fresard, Project Manager
US Army Corps of Engineers, Sacramento District
533 West 2600 South, Suite 150
Bountiful, Utah 84010
The Corps is particularly interested in receiving comments related to the proposal's probable impacts on the affected aquatic environment and the secondary and cumulative effects. Anyone may request, in writing, that a public hearing be held to consider this application. Requests shall specifically state, with particularity, the reason(s) for holding a public hearing. If the Corps determines that the information received in response to this notice is inadequate for thorough evaluation, a public hearing may be warranted. If a public hearing is warranted, interested parties will be notified of the time, date, and location. Please note that all comment letters received are subject to release to the public through the Freedom of Information Act. If you have questions or need additional information please contact the applicant or the Corps' project manager Nicole Fresard, (801) 295-8380 ext. 8321, Nicole.D.Fresard@usace.army.mil.
Attachments: Two (2) Enclosures