Comments Period: April 6, 2012 – May 7, 2012
SUBJECT: The U.S. Army Corps of Engineers, Sacramento District, (Corps) is evaluating a permit application to construct the Dutch Slough tidal marsh restoration project, which would result in impacts to approximately 200.4 acres of waters of the United States, including wetlands (waters of the U.S.), in or adjacent to the San Joaquin River, Dutch Slough, Little Dutch Slough, Emerson Slough and Marsh Creek. This notice is to inform interested parties of the proposed activity and to solicit comments. This notice may also be viewed at the Corps web site at http://www.spk.usace.army.mil/regulatory.html.
AUTHORITY: This application is being evaluated under Section 10 of the Rivers and Harbors Act of 1899 for structures or work in or affecting navigable waters of the United States and Section 404 of the Clean Water Act for the discharge of dredged or fill material in waters of the United States.
APPLICANT: Gail Newton, California Department of Water Resources, 901 P Street, Sacramento, California 95814
LOCATION: The approximately 1270-acre site is located south of and adjacent to Dutch Slough, generally east of and adjacent to Marsh Creek, and generally north of and adjacent to the Contra Costa Canal, approximate Latitude 38.0029515594976°, Longitude -121.663925839473°, within the City of Oakley, in Contra Costa County, California. The project is within Sections, 20 and 29, of Township 2 North, Ranges 3 East and can be seen on the CA-JERSEY ISLAND USGS and CA-BRENTWOOD USGS Topographic Quadrangle. Township 2 N, Range 3 E, Mount Diablo Meridian, Latitude 38.0029515594976°, Longitude -121.663925839473°, in Contra Costa County, California. The project site consists of three parcels, the Gilbert, Emerson and Burroughs parcels, which historically were tidal marsh, these parcels were reclaimed in the late 1800’s and converted to dairy farms and associated irrigated pastureland.
PROJECT DESCRIPTION: The applicant is proposing to construct a tidal marsh restoration project to reestablish natural ecological processes and provide habitat to benefit native species. Proposed restoration activities would result in fill of 200.4 acres of waters of the U.S., including 176.0 acres of wetlands and 24.4 acres of other waters. These impacts would be associated with placement of up to 572,100 CY of material in waters of the U.S.; placement of up to 15,900 linear feet of rock armoring along the Emerson and Gilbert parcel perimeter levees; construction of a culvert in Little Dutch Slough under the reconstructed southern flood control levee; installation of a screened and gated culvert to provide intake water for the managed non-tidal marsh on the Gilbert parcel; construction of flood protection levee segments; and construction of four public access bridges. An additional 73.4 acres of waters of the U.S., including 60.1 acres of wetlands and 13.3 acres of other waters, would be excavated to achieve the proposed restoration objectives. Excavation in waters of the U.S. would be associated with creation of low and mid tidal marsh and tidal channels; enlargement of Little Dutch Slough; construction of levee breaches on Marsh Creek, Dutch Slough, and Emerson Slough; excavation of a subtidal open water area on the Emerson parcel; creation of a new toe ditch and two new open water areas on the Gilbert parcel; creation of a new drainage ditch on the Burroughs parcel; and excavation in the soils borrow area to obtain borrow material.
Approximately 4.4 acres of waters of the U.S. would also be temporarily disturbed during project construction. Temporary impacts would be associated with construction of the temporary crossing of Marsh Creek to provide access to the soils borrow area; construction and removal of cofferdams to dewater limited reaches of Marsh Creek (in the vicinity of the Marsh Creek crossing), Little Dutch Slough (to allow for slough enlargement, construction of the new berm on the Gilbert parcel, construction of the southern boundary levee crossing, and to facilitate levee breaching on the Gilbert parcel), and Emerson Slough (to install the screened and gated culvert to provide intake water for the managed non-tidal marsh on the Gilbert parcel); and installation and removal of temporary culverts to facilitate on-site irrigation during the tule cultivation period. Finally, an additional 2.8 acres of tidal marsh along the northwest corner of the Burroughs parcel may be converted to open water as a result of anticipated tidal scour. Conversion of this area is considered a potential indirect impact of the proposed project. Once complete, the proposed project would result in a net increase of approximately 380.5 acres of waters of the U.S., including 321.8 acres of wetlands and 58.7 acres of other waters. This net increase would be realized through the conversion of existing habitat types, including some that are currently considered wetlands or other waters.
The proposed project would restore tidal marsh and riparian habitat within the 1,178-acre restoration area (Figure 2) and would include the following major components:
- Restoration of approximately 560 acres of tidal marsh, including about 10 acres of tidal channels; 26 acres of riparian forest; 76 acres of managed non-tidal marsh; 97 acres of subtidal open water habitat, and 4 acres of native grassland.
- Enhancement of approximately 26 acres of managed non-tidal marsh and 173 acres of irrigated pasture.
- Preservation and enhancement of habitat suitable for special-status species, including Swainson’s hawk (Buteo swainsoni), giant garter snake (Thamnophis gigas), and California black rail (Laterallus jamaicensis coturniculus).
- Protection of existing infrastructure through construction and rehabilitation of flood protection levees and relocation and replacement of some infrastructure.
- Development of public access infrastructure.
- Implementation of ongoing maintenance and monitoring commitments.
As described in more detail below, the restoration area is currently comprised primarily of irrigated pasture. The northern portions of the restoration area have subsided to elevations below sea level as a result of historic and ongoing irrigation water drainage to support agricultural activities. Proposed restoration activities would be accomplished by excavating soils from high areas across the three parcels and from the soils borrow area, and distributing those soils across the restoration area to bring ground levels to desired elevations to establish tidal marsh. After the restoration area has been graded, the parcels would be inundated to levels suitable for establishing tules (Schoenoplectus spp). Once tules have established (one to two years), the levees that surround the restoration area would be breached in several locations to open the area to tidal influence. In addition, Marsh Creek, which currently flows along the western boundary of the Emerson parcel, would be rerouted onto its historical delta through the restored marsh floodplain to a new outlet at Dutch Slough.
Most of the restoration area has been designed to create tidal marsh and tidal channels. In addition, one area of subtidal open water would be created; an area of non-tidal marsh would be preserved, expanded, and enhanced; and an area of irrigated pasture would be preserved and enhanced. The subtidal open water would be created in the northern portion of the Emerson parcel where subsidence has resulted in elevations too low for practical restoration of marsh habitat. The existing non-tidal marsh in the northern portion of the Gilbert parcel would be maintained and enhanced to provide habitat for California black rail, as well as habitat features suitable for use by giant garter snake (e.g., irrigation canals). The northern portions of the Burroughs parcel would be maintained as irrigated pasture and managed to provide enhanced nesting and foraging habitat for Swainson’s hawk. Other elements of the project would include widening and reconfiguring portions of existing levees to improve levee protection, provide safe public access, and enhance habitat conditions; constructing new flood control levee segments along the southern and eastern project boundaries; constructing bridges over levee breaches; and relocating and/or protecting existing infrastructure on-site.
Habitat Restoration and Enhancement Design Components
Approximately 560 acres of tidal marsh, 26 acres of riparian forest, 76 acres of managed non-tidal marsh, 97 acres of subtidal open water, and 4 acres of native grassland would be restored using on-site grading, placement of fill material, and re-vegetation techniques. In addition, approximately 26 acres of managed non-tidal marsh and 173 acres of irrigated pasture would be enhanced by modifying their management to benefit wildlife species.
Target Habitat Types
This following provides a description of each habitat type that would be restored or enhanced under the proposed project, including plant species detail, fish and wildlife expected to use the habitats, and consideration of invasive species. Table 1 summarizes the estimated restored and conserved or enhanced habitat acreages after the proposed project has been constructed.
The proposed project would restore or enhance approximately 564 acres of tidal marsh in the restoration area (Figure 2, Table 1). As described below, tidal marsh includes four different types of habitats: low marsh, mid marsh, high marsh, and tidal channels. The vast majority of restored tidal marsh habitats in the restoration area would be comprised of low marsh and mid marsh. Small acreages of high marsh and tidal channels would also be restored.
Low marsh elevations would range between -0.8 feet to +0.2 feet National Geodetic Vertical Datum (NGVD) (DWR et al. 2010) (Figure 3). This habitat type would likely consist of a monoculture of California bulrush (Schoenoplectus californicus) given its ability to survive long periods of deep inundation (SCC 2006).
Fishes would commonly occupy the low marshplain when it is flooded and some (e.g., small sculpins and gobies) may be able to persist in shallow depressions and pannes during low tide. In the lowest elevations, Sacramento splittail (Pogonichthys macrolepidotus) may spawn in perennially flooded vegetation. Juvenile chinook salmon (Oncorhynchus tshawytscha) may occupy lower order tidal channels in the low marsh to forage on larval and adult insects. Low tidal marsh would also provide foraging habitat for several bird species, including song sparrow (Melospiza melodia) and California black rail, as well as nesting habitat for species such as marsh wren (Cistothorus palustris).
Based on the available information, the overall project purpose is the restoration of tidal marsh, channels and riparian forest. Additionally the project would enhance non-tidal marsh and irrigated pasture. The applicant believes there is a need to restore tidal marsh habitat within the Sacramento/San Joaquin Delta. The attached drawings provide additional project details.
Environmental Setting: There are approximately 572.8 acres of waters of the United States including wetlands within the 1270 acre project area. The site, which historically supported 3 dairies, is characterized by irrigated pasture which are bordered and/or bisected by sloughs or other waters which are subject to the tidal influence of the San Joaquin River. The irrigated pasture supports a number of seasonal wetlands, agricultural drainages, ponds and perennial wetlands.
Alternatives. The applicant has provided information concerning project alternatives. Information concerning project alternatives is 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 proposed project would restore and enhance tidal and non-tidal wetlands and other waters of the U.S. The proposed project would increase the area of waters of the U.S. therefore, mitigation would not be required as the overall project would result in a net gain in acreage, functions and services of waters.
OTHER GOVERNMENTAL AUTHORIZATIONS: Water quality certification or a waiver, as required under Section 401 of the Clean Water Act from the California Regional Water Quality Control Board, Central Valley Region is required for this project. The applicant has indicated they have applied for certification.
HISTORIC PROPERTIES: Based on the available information including applicant's report entitled Department of Water Resources, Negative Archaeological Survey Report, Contra Costa County, Dutch Slough Wetland Restoration Project. Potentially eligible cultural resources may be affected by the proposed project. 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 proposed activity may affect Federally-listed endangered or threatened species or their critical habitat. The Corps will initiate consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, pursuant to Section 7 of the Endangered Species Act, as appropriate.
ESSENTIAL FISH HABITAT: The proposed project may adversely affect Essential Fish Habitat. The Corps will initiate consultation with the National Marine Fisheries Service, pursuant to Magnuson-Stevens Fishery Conservation and Management Act, as appropriate.
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-2004-00043 must be submitted to the office listed below on or before May 7, 2012.
William Guthrie, Project Manager, US Army Corps of Engineers, Sacramento District, Regulatory Division, Delta Branch
1325 J Street, Room 1350, Sacramento, California 95814-2922, Email: William.H.Guthrie@usace.army.mil
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 William Guthrie, 916-557-5269, William.H.Guthrie@usace.army.mil.
Attachments: 3 drawings 1Table