SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a permit application to construct the Grand County Gore Canyon Whitewater Park project, which would result in permanent impacts to approximately 0.22 acre of waters of the United States, and temporary impacts to 2.27 acres of waters of the United States. 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: Grand County, Attention: Lurline Curran, P.O. Box 294, Hot Sulphur Springs, CO 80451-0294
AGENT: Jason Carey, RiverRestoration.org, P.O. Box 248, Carbondale, CO 81623-0248,
LOCATION: The Gore Canyon Whitewater Park site would be located on the Colorado River at the Pumphouse Recreation Area managed by the Bureau of Land Management (BLM), within Section 12, Township 1 South, Range 82 West, Sixth Principal Meridian, Latitude 39.98813°, Longitude -106.51099°, about seven miles southwest of the town of Kremmling, in Grand County, Colorado, and can be seen on the CO-RADIUM USGS Topographic Quadrangle (Figure 1).
PROJECT DESCRIPTION: The applicant is proposing to construct in-channel river recreation features within approximately 250 linear feet of the Colorado River (see Figures 2-7). The total volume of fill material to be placed below the ordinary high water mark of the Colorado River is approximately 1,731.9 cubic yards (CY) of native and imported boulders, pre-cast concrete, and native alluvium over a 0.22-acre area. The total length of impacted river bank would be approximately 70 linear feet on the south side and 50 linear feet on the north side of the river. The proposed project includes the following features:
Grade Control Structure: A grade control structure would be constructed in the channel, resulting in the discharge of approximately 1,480.4 CY of native and imported boulder and native cobble material into 0.21 acre below the ordinary high water mark of the river. The material would be placed by a trackhoe.
Wave Features: The wave features would be integrated into the grade control structure, and involve the discharge of a total of 61.5 CY of fill material comprised of pre‐cast concrete with reinforcing rebar material and backfilled with ready mix. A crane and pump truck would be used to place the wave features. All areas constructed with cement would be isolated from flowing waters and materials contained and properly cured or disposed of.
Bank Terracing: Bank terracing would be constructed to accommodate spectator seating. Riparian vegetation would be replaced with natural boulders along 70 linear feet of the south bank of the channel. Fill material for the bank terracing would consist of approximately 220 CY of boulders with gravel and filter fabric bedding placed by a trackhoe. Approximately 170 CY of this material would be discharged into 0.01 acre below the ordinary high water mark of the river. A 0.025 acre riparian area would be converted to boulder-lined, terraced bank for the purposes of river ingress and egress and spectator seating.
Random Boulders: Approximately 20 CY of boulders would be randomly placed by a trackhoe along both shorelines downstream of the grade control structure to create near bank eddies for upstream navigation of small water craft.
The recreation features will span the entire approximate 160-foot width of the channel. The applicant states that no significant fluvial geomorphic changes are expected due to the proposed enhancements, and that the river recreation features would not alter hydrodynamics in the reach beyond local impacts immediately surrounding the features. Flow velocities would
only see localized changes, which are dissipated in the hydraulic jumps and only extend a
short distance downstream.
According to the applicant, the Gore Canyon Recreational In-Channel Diversion (RICD) is designed to provide different recreational experiences by capturing and controlling the entire flow of the river and putting to beneficial use flows ranging from 860 cubic feet per second (cfs) to 2,500 cfs. An extreme minimum flow of 280 cfs is anticipated to provide fish and boat passage and the structure is designed to pass the 100‐year flow of 13,600 cfs. The pre-cast concrete pillars used to initiate the hydraulic jumps serve a secondary purpose during extreme low flow scenarios, acting as holding areas for fish prior to passage through the 2.5-foot gaps between the pillars. During moderate to high flows (1,100 to 2,500 cfs), the river right feature is designed to become the primary recreation feature and the river left feature is anticipated to produce a weak hydraulic jump. At very high flows (13,600 cfs), both features are designed to submerge to limit impacts to the 100-year flood conveyance, as well as to reduce stress on structures during these lower probability events. The feature is designed to accommodate existing sediment supply rates within the reach and to maintain sediment continuity upstream and downstream of the feature.
Temporary impacts during construction include heavy equipment access through the banks on both sides of the river, and dewatering of the river bed during construction. Dewatering entails the placement of an alluvial coffer dam to divert water around the construction area. Half of the river channel would be dewatered at a time, dewatering about 500 feet of channel. The river would continue to flow through the other half of the channel. The coffer dam structures would temporarily impact 0.18 acre of river bed. The total area of temporary impact to the Colorado River during construction, including dewatering and track equipment traveling on the river bed, would be 2.27 acres. Staging areas would be located in uplands adjacent to the project which are currently disturbed by the development and ongoing use of the Pumphouse Recreation Area.
Based on the available information, the project need is to provide a reasonable recreational whitewater experience, which will boost the socio-economic benefits to the region; and to provide permanent protection for in-stream flows in a segment of the Upper Colorado River in Grand County. The overall project purpose is to construct a whitewater park on the Colorado River in Grand County. The applicant’s stated project purpose is to construct a whitewater feature in the Upper Colorado River at the Pumphouse Recreational Area in accordance with the approved designs for the Recreational In-Channel Diversion (RICD) that supported the water right for the project as filed in Case No. 10CW298, Water Division No. 5, and approved by the Colorado Basin 1177 Roundtable and Colorado Water Conservation Board. The applicant believes there is a need to provide a river recreational experience; and in doing so, will: Implement an important part of the Colorado River Cooperative Agreement (CRCA) among Denver Water and over 30 west slope entities that provides for the development of a RICD below Gore Canyon; and provide permanent protection for flows in support of the Outstanding Remarkable Values (ORV) for Recreational Floatboating in the Upper Colorado River as part of the BLM Resource Management Plan in support of the Wild &Scenic Rivers Stakeholders Group Alternative Management Plan.
The BLM is the lead federal agency responsible for reviewing the project pursuant to the National Environmental Policy Act because the proposal is located entirely on lands managed by the BLM.
Environmental Setting. The project site is located on the Colorado River within the Pumphouse Recreation Area managed by the BLM. The Pumphouse Recreation Area sees an average of 60,000-70,000 visitors per year, and consists of 20 campsites, 5 boat ramps, 12 vault toilets, a public water system, 3 information kiosks, 2 gravel parking lots, and trash collection. About 55 commercial rafting outfits use this reach of the river. The project is at the head of a double riffle pool sequence that extends approximately 0.5 mile downstream before transitioning into an island-braided reach similar to the river environment upstream of the project site. The proximate downstream riffle is monitored by Colorado Parks and Wildlife for salmon fly production. The last riffle is modified by a diversion structure. Both riffles are armored through the winnowing process and the reduction in transporting hydrology due to transmountian diversions, reservoirs and flood control.
There are no wetlands within the limits of disturbance at the project site. The riparian areas are primarily populated by coyote willows.
Flows in the Colorado River have been measured at a location approximately 4.7 miles upstream of the proposed Gore Canyon Whitewater Park near Kremmling, Colorado stream gage, Station ID# 09058000, (“the Kremmling gage”), operated by the U.S. Geological Survey during water years 1905‐1918, 1962‐1970, and 1972 through the present. The Kremmling gage has a drainage area of approximately 2,382 square miles and includes the headwaters of the Colorado River and Willow Creek, Fraser River, Williams Fork River, Blue River and Muddy Creek basins. Stream flows at the Kremmling gage reasonably represent the physical supply at the proposed Whitewater Park. The Kremmling gage includes more than 99% of the drainage area tributary to the proposed Whitewater Park. The remaining drainage includes Canyon Creek and a few small unnamed tributaries that have small and relatively low elevation drainage areas.
Alternatives. The applicant has provided information concerning project alternatives. The applicant evaluated the feasibility of constructing in-channel whitewater features at multiple sites on the Colorado River through Grand County, including five locations from the Blue River confluence down to the Grand County line. Upstream of the Blue River confluence, the applicant identified a potential future whitewater park site at Hot Sulphur Springs, which is included in their RICD water right decree, but has chosen not to construct this site first because there is a greater volume of water available to the RICD at the Pumphouse site. The applicant also provided information regarding the feasibility of an off-channel whitewater park diversion for the purposes of river recreation enhancements, indicating that it would be more costly and require a larger diversion structure in the river channel than an in-channel whitewater feature. Additional information concerning project alternatives may be available from the applicant or their agent. 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. The applicant has proposed that practical measures will be implemented to avoid or minimize impacts to aquatic resources and that no compensatory mitigation should be required for the project. The applicant has indicated that willows would be collected on-site and plugged into the margins of the boulder structure below the ordinary high water mark of the river for approximately 200 square feet.
OTHER GOVERNMENTAL AUTHORIZATIONS: Water quality certification or a waiver, as required under Section 401 of the Clean Water Act from the Colorado Department of Public Health and Environment (CDPHE), is required for this project. The applicant has indicated they have applied for certification. The applicant will also be required to obtain a Right of Way Permit from BLM.
HISTORIC PROPERTIES: The BLM, as lead federal agency, will consult as appropriate with the State Historic Preservation Officer (SHPO) under Section 106 of the National Historic Preservation Act (NHPA). The BLM will provide the Corps with the appropriate documentation to demonstrate compliance with NHPA requirements. The Corps will review the documentation and determine whether it is sufficient to address Section 106 compliance, or whether additional Section 106 consultation is necessary.
ENDANGERED SPECIES: The BLM, as lead federal agency, will consult as appropriate with the U.S. Fish and Wildlife Service (FWS) under Section 7 of the Endangered Species Act (ESA). The BLM will provide the Corps with the appropriate documentation to demonstrate compliance with ESA requirements. The Corps will review the documentation and determine whether it is sufficient to address Section 7 compliance, or whether additional Section 7 consultation is necessary.
The above determinations are based on information provided by the applicant and our preliminary review.
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-2013-00580, must be submitted to the office listed below on or before June 2, 2014.
Lesley McWhirter, Project Manager
US Army Corps of Engineers, Sacramento District
Colorado West Regulatory Branch
400 Rood Avenue, Room 224
Grand Junction, Colorado 81501-2563
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, Lesley McWhirter, 970-243-1199, x17, Lesley.A.McWhirter@usace.army.mil.
Attachments: 7 drawings