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Under the Corps' Regulatory Program, a public notice is the primary method for advising all interested parties of a proposed activity for which a permit is sought. Soliciting comments and information necessary to evaluate the probable impacts on the public interest. Public notices are also published to inform the public about new or proposed regulations, policies, guidance or permit procedures.

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SPK-2013-00254, Gunnison River, Mesa County, CO

Posted: 7/29/2013

Expiration date: 8/26/2013


CESPK-RD-C

SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a permit application to construct the Whitewater Gravel Pit project, which would result in impacts to approximately 2.87 acres of wetlands and 2.04 acres (900 linear feet) of the Gunnison River, which are 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: Whitewater Building Materials Corporation, Attention: Mr. Mark Gardner, 940 10th Street, Grand Junction, Colorado 81501, Telephone: (970) 242-7538

AGENT: Mr. Peter Kearl, O’Connor Design Group, Inc., 2350 G Road, Grand Junction, Colorado 81505, Telephone: (970) 985-9606

LOCATION: The approximately 100-acre site is located one-half mile west of the Town of Whitewater, at the Gunnison River, within Section 15, Township 2 South, Range 1 East, and Section 28, Township 12 South, Range 99 West, Ute Meridian, Latitude 38.98490°, Longitude -108.46584°, Mesa County, Colorado, and can be seen on the CO-WHITEWATER USGS Topographic Quadrangle (Figure 1).

PROJECT DESCRIPTION: The applicant is proposing to construct an in-stream gravel mine. The proposed work is depicted on Figure 2 and consists of the following:

1. Bank stabilization utilizing sod mats and Toe Wood Benches (Figure 3).

2. Removal of 2.8 acres of vegetated gravel bars at the upstream reach of the project area (see Figure 13).

3. Excavation of a new, overly-widened, side channel through the project area. The intent of the new channel construction is to encourage gravel deposition with the intent of gravel extraction from the new side channel on a regular basis. The applicant asserts that the proposed new channel is designed to ensure adequate velocities to transport bedload material. In the center portion of the new side channel, the constructed width and depth would be substantially increased. Figure 4 shows a cross-sectional diagram of the new channel at the widest point. With the increased channel cross-sectional area, the river flow velocity would decrease causing the bedload and a portion of the suspended load to settle out in the over-widened channel area. This process would generally occur during the spring runoff season when the bulk of bedload transport occurs. During this time, it is anticipated that sand and gravel would be deposited in the portion of the new side channel where the cross-sectional area has been increased. Once river water levels decline, mining would begin by removing the newly deposited sand and gravel. The mining plan proposes the installation of two temporary coffer dams (see structure number 10 on Figure 2 and coffer dam cross-section on Figure 5) on the up- and down-stream portions of the new channel to dewater the channel to allow for the excavation of the accumulated sand and gravel. The purpose of the temporary coffer dams is to minimize sediment transport during gravel extraction. The coffer dams would be constructed of concrete blocks covered with local gravel material and would be between 4 and 12 feet at the top of the coffer dam, 16 feet in width at the bottom, and extend the approx. 167-foot width of the channel. The concrete blocks would be placed on the river side; the gravel would be placed on the isolated channel or “lake” side. To further clarify the coffer dam design, the upstream coffer dam would have the concrete blocks on the east side and pit run on the west side. The downstream coffer dam would have the concrete blocks on the west side and the pit run on the east side. The coffer dams would be installed during the fall months and removed following extraction of the gravel within the newly-constructed side channel. The applicant believes that this approach would result in a renewable gravel resource.

4. Construction of two cross vane structures are intended to split flows of the Gunnison River between the new side channel and the existing channel. A cross vane (Figure 6 and structure number 7 in Figure 2) would be installed at the mouth of the new channel and another cross vane would be installed on the main channel of the river (structure number 2 in Figure 2) to provide channel grade control and prevent erosion and headcutting upstream. Large rocks, 3 to 5 feet in diameter, would be used to construct the vanes.

5. Construction of one rock J-hook structure is proposed for bank stabilization (number 9 on Figure 2 and Figures 7 and 8). The J-hook would be constructed with 3 to 5-foot diameter boulders, at a 30-degree angle from the bank, and extend 1/3 the width of the river. This structure is proposed to be approximately 110 feet long.

6. Construction of a 150-foot long sill (number 6 on Figure 2 and Figure 9) is proposed to assist in the development of a point bar and floodplain in the area of island removal. The sill would be Constructed out of 2-foot diameter rock.

7. Two ponds are proposed to be constructed to the north and south of the proposed new side channel (numbers 4 and 5 in Figure 2, and Figures 10, 11 and 12). The main purpose of the pond construction is for gravel extraction. The large northern pond (number 4 of Figure 2) would have an outlet near the downstream river bend adjacent to the railroad track. The applicant asserts that groundwater would enter the pond and discharge from the outlet into the main channel of the river and that this flow would diminish the force of the main river channel and aid in the stabilization of the river bank directly below the railroad tracks. The outlet is proposed to be lined with rocks designed to prevent erosion from high runoff events. The height of the outlet would be placed at an elevation that prevents the pond from becoming a breeding ground for predatory fish. The smaller southern pond (number 5 of Figure 2) is proposed to be excavated in the southwestern portion of the site and connected to the new channel by a small outlet. All gravel extracted from these ponds would be moved to the Whitewater operations area to the north for processing and eventual sale. Much of the proposed compensatory wetland mitigation is proposed to be constructed around the perimeter of these two ponds. However, the applicant states that the construction schedule of the ponds needs to be flexible and is dependent on the efficiency of the new channel in capturing sand and gravel and the demand by the local community for aggregate products. The construction of the ponds will not impact the existing Gunnison River channel.

Based on the available information, the Corps has determined that the overall project purpose is sand and gravel extraction. The applicant believes that gravel resources in the Grand Junction area are dwindling and that aggregate based materials will become more expensive for Grand Junction residents without the creation of a sustainable gravel resource. The attached drawings provide additional project details. Gunnison River impacts are summarized in Table 1. Wetland impact and mitigation acreages are summarized in Table 2.

ADDITIONAL INFORMATION:

    Environmental Setting. The applicant has delineated wetlands at the site and identified approximately 6.66 acres of Palustrine Scrub-Shrub wetlands. The proposed project site is located in and adjacent to the Gunnison River at an approximate elevation of 4,640’ above mean sea level. The southern portion of the site consists of a cottonwood grove with an active bald eagle nest. The eagle nest is proposed to be removed in the applicant’s preferred alternative. Other vegetation within the project area includes unidentified willow species, tamarisk, inland salt grass, kochia, common three-square and Russian knapweed. There are approximately 2.8 acres of vegetated gravel bars in the river at the east end of the project boundary which are proposed to be removed (Figures 13). The Gunnison River and its 100-year floodplain at this location are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus).

According to the applicant, the proposed channel design is based on bank full flow conditions at a 1.5 year reoccurrence interval. The reoccurrence interval for the Gunnison River, based on measurements at the Whitewater USGS Gaging station, is approximately 8,640 cubic feet/second. At bank full flow conditions the channel depth is approximately 7.8 feet and the mean velocity is 5.2 feet/second. Channel width is approximately 200 feet, however, there is a large amount of variability in the data, possibly indicating changes in the channel, either man-made or natural, during the operational period of the gage. Cross sectional area of the channel at bank full conditions is 1,700 square feet. Meander geometry of the Gunnison River is partially controlled by the confining nature of the canyon both up- and downstream of the site. Measurements of belt width and meander wavelength of these river reaches show a large degree of variability depending on the structural control exerted by the incised canyon. The average meander wavelength, as measured from one meander crest to adjacent meander crest, is 3,240 feet with a variance as high as plus or minus 1200 feet. The meander belt width averages 870 feet with a variance as high as plus or minus 300 feet. The existing meander wavelength in the project area is 3,600 feet, well within the variance observed for the Gunnison River, but the belt width of 2,100 feet is more than double the average value and higher than any value measured on the river except where narrow entrenched meanders control the river.

    Alternatives. The applicant has provided information concerning two project alternatives, in addition to their preferred alternative described above. Alternative 1 would stabilize the northwest bank of the upstream section of the river using the toe wood stabilization method, and mine the extent of the project area, excluding the wetlands on site (Figure 15). The applicant would then install a “vortex tube” (Figures 15 and 16) and a cross vane structure in the Gunnison River. A vortex tube would include the installation of a 200-foot long, 24-inch diameter steel pipe in the river bed with the upper surface of the pipe at the same elevation of the river bed. A 14-inch slot, 120 feet in length, would be cut in the pipe to allow bed load material from the river to enter the pipe and be transported to the pond. The vortex motion in the pipe created by the river current effectively removes the gravel from the river into the excavated off-stream pond. Mining equipment would remove gravel from the pond during the spring runoff season. Under Alternative 2 (Figure 17), the applicant would mine the extent of the uplands within the project area using the currently permitted traditional open pit method. The toe wood bench on the upstream bank would be constructed in order to prevent further erosion to that bank. The toe wood bench would extend into the river approximately 25 to 30 feet to stabilize the bank and help to restore the lost wetland fringe along that section of the river bank. The applicant asserts that Alternatives 1 and 2 would result in large ponds separated from waterways by narrow riprapped berms, no improvement to the hydraulic efficiency of the river, the removal of an existing cottonwood stand, and would not enhance the aquatic habitat for endangered fish species. The applicant states that they desire to develop a limited, sustainable economic resource (sand and gravel) important to the local community while protecting and enhancing the environment.

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 to create 24.2 acres of wetlands (Figures 10, 11 and 12) around the created north and south ponds. Table 2 shows the amount and location of proposed wetland creation areas. Figure 18 is a plant list for the proposed wetland mitigation sites. At this time the applicant has not provided a complete compensatory wetland mitigation or monitoring plan. The applicant has proposed to create 24.2 acres of wetlands, to monitor the site for bank stability, to conduct channel cross-section monitoring, and to conduct sediment transport surveys. The applicant proposes to submit an annual monitoring and maintenance report before the end of each year to the Corps. The report would document field surveys and maintenance activities conducted for the year. Photo documentation of the site will be included in the report. No fish habitat monitoring is proposed; however, the applicant hopes this project will generate interest by an outside party to develop, conduct, and finance a fish habitat monitoring program.

OTHER GOVERNMENTAL AUTHORIZATIONS:

Water quality certification or a waiver, as required under Section 401 of the Clean Water Act from the Water Quality Control Division is required for this project. The applicant has indicated they have applied for certification.

The applicant has applied for a take permit from the U.S. Fish and Wildlife Service, under the Bald and Golden Eagle Protection Act, to remove the bald eagle nest in association with this permit.

HISTORIC PROPERTIES: Based on the available information, potentially eligible cultural resources may be affected by the proposed project. The applicant has not prepared a cultural resource survey to date. The Corps has requested that the applicant survey the site for cultural resources and provide a cultural resources report. The Corps will initiate consultation with the State Historic Preservation Officer, pursuant to Section 106 of the National Historic Preservation Act, as appropriate.

ENDANGERED SPECIES: The proposed activity may affect Federally-listed endangered fish, Colorado pikeminnow (Ptychocheilus lucius), bonytail chub (Gila Elegans), humpback chub (Gila cypha) and razorback sucker (Xyrauchen texanus) and their critical habitat. The Corps will initiate formal consultation with the U.S. Fish and Wildlife Service, pursuant to Section 7 of the Endangered Species Act.

ESSENTIAL FISH HABITAT: The proposed project will not adversely affect Essential Fish Habitat (EFH) as defined in the Magnuson-Stevens Fishery Conservation and Management Act.

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-2013-00254 must be submitted to the office listed below on or before August 26, 2013.

Nathan Green, Project Manager
U.S. Army Corps of Engineers, Sacramento District
Colorado West Regulatory Branch
400 Rood Avenue, Room 224
Grand Junction, Colorado 81501-2563
Email: Nathan.J.Green@usace.army.mil
Telephone: (970) 234-1199 extension 12

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 Nathan Green, 970-243-1199 extension 12, Nathan.J.Green@usace.army.mil.

Attachments: 18 Figures, 2 Tables