«DRAFT ENVIRONMENTAL ASSESSMENT ENVIRONMENTAL ASSESSMENT FOR THE COLUMBIA STOCK RANCH SECTION 536 ECOSYSTEM RESTORATION PROJECT The environmental ...»
Alternative 5, the Proposed Action, reconnected the ponded areas west of the railroad to the third levee breach via the installation of two bridges in the railroad embankment. Additionally, the access road between Highway 30 and the existing residence would be graded to match adjacent topography and facilitate hydrologic connectivity to the southwest portion of the project site.
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3.4. Comparison of Alternatives Each alternative, including the Proposed Action (described in detail above) was evaluated for environmental benefits and adverse impacts relative to the goals and objectives stated above.
While No Action Alternative and Alternatives 1-4 provided fewer environmental impacts, they also provided fewer ecological benefits compared to Alternative 5, the Proposed Action. Over time, the proposed project is expected to provide the greatest environmental benefit to fish and wildlife, increasing wetland quality and quantity across the project site.
3.5. Best Management Practices The Proposed Action would primarily result in beneficial environmental effects. However, in areas with the potential for deleterious effects, either short-term or long-term, best management practices (BMPs) would be used to minimize adverse impacts. All project actions would incorporate BMPs recommended by NOAA Fisheries and Oregon Department of Fish and Wildlife (ODFW) to protect fish and wildlife, as well as BMPs recommended by the Oregon Departments of State Lands and Environmental Quality to protect water quality and waters of the U.S.
The Corps would also follow all recommendations specified in the permitting and compliance documents associated with the proposed CSR restoration project. The proposed BMPs include,
but are not limited to the following:
Clearing and grading of vegetation would be limited to the minimum practicable extent and would occur immediately preceeding active construction to minimize potential impacts from increased erosion;
Trees or vegetation not removed for construction would be maintained and protected against damage;
Sediment fencing or another effective erosion control method would be installed in areas along the ordinary high water line to prevent siltation from adjacent work in upland areas;
All completed bank sloping and stream channel work would be covered with mulch or fiber matting and revegetated as soon as practicable;
Construction work would be sequenced and timed to occur during the ODFW approved in-water work window to limit erosion and sedimentation and minimize impacts to fish and aquatic wildlife;
Staging areas would be located in previously disturbed uplands and all staging and stockpile areas would be restored after construction is complete;
All areas disturbed during construction of the Proposed Action would be seeded or replanted with native vegetation following construction to support establishment of a native plant community and to prevent erosion and sedimentation;
The Corps would implement the recommended guidance of the Oregon State Historic and Preservation Office (SHPO) for archaeological resources and would conduct monitoring during all ground disturbing activities; and Prior to construction, fish salvage and removal would be performed by a qualified fisheries biologist in all in-water work areas using guidelines from by NOAA Fisheries and ODFW.
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3.6. Monitoring and Adaptive Management Plan Under the Section 536 restoration authority, the Corps would monitor habitat changes and species response according to requirements of Section 2039 of Water Resources Development Act of 2007 and subsequent Corps implementation guidance. Monitoring would be conducted until such time that the Corps determines the project has achieved success and it is anticipated this would require five years of monitoring following project implementation. Ecosystem monitoring would evaluate physical and biological responses to the proposed restoration actions. In addition, all ground-disturbing activities associated with construction, including all excavations, grading and surface reconfigurations, would be monitored by professional archaeologists during construction for cultural and historic resources.
A monitoring and adaptive management plan has been developed to ensure the success of the recommended ecosystem restoration plan in meeting project objectives (refer to objectives in Section 1.4). Additional monitoring could occur at the CSR project site to support and inform research that the agencies conduct in conjunction with other programs, which would be separate from the monitoring conducted specifically to evaluate project success following implementation of the Proposed Action.3 If adaptive management actions are warranted, the plan contains triggers to reevaluate the status of the project and recommend action needed to address issues so the project can again meet its restoration potential. The monitoring plan would include activities to measure connectivity to the mainstem Columbia River as a means of ensuring the project successfully restores hydrologic connectivity, meeting Objective 1.
Connectivity would be evaluated by monitoring channel morphology at the levee breaches and tidal channels by measuring cross-sectional dimensions of the constructed channels. Similarly, fish surveys would be conducted to document the presence of juveniles salmonids and describe the composition of the fish in the project area following project implementation. Monitoring results from fish surveys would be used to ensure the project area is hydrologically connected to the Columbia River providing unencumbered access to critical foraging and rearing habitats on the project site for juvenile salmonids, thereby meeting Objectives 1 and 3.
Additional biological parameters would be monitored via annual surveys to evaluate the presence/absence of fish and wildlife, including juvenile salmonids, and the composition of native plant communities, meeting Objectives 2, 3, and 4. Vegetation transects and photo points could be used to measure species composition, survival rates and percent cover of vegetation in tidal channel, marsh, wetland, riparian and forested upland habitats. Survey transects through the CSR project area would be used to evaluate the percent cover of native versus non-native vegetation, including an evaluation of percent shade of tidal channels and wetland habitats contributing to off-channel habitat quality and the composition of native wetland plant communities, supporting overall productivity and the growth and survival of juvenile salmonids in the CSR project area, meeting Objectives 2 and 4.
Additional data could be collected to inform research programs, examples of which include the installation of sediment pins to evaluate accretion, erosion and settlement in the tidal channels and marsh habitats following reconnection to the tidal prism. Water quality could be evaluated via temperature sensors to monitor changes across the CSR project site following implementation of restoration measures, informing how project actions change or impact (beneficial or adverse) the affected environment. Research monitoring results would provide lessons learned, informing future restoration projects to ensure successful implementation in meeting project objectives.
April 22, 2016 Page 19 Adapative management triggers include the accretion of sediment such that hydrologic connectivity between the mainstem Columbia River and the CSR project site is blocked, there is a loss of off-channel rearing habitat, an absence of juvenile salmonids, or a widespread loss of native plant communities. If adaptive management actions are warranted, the Corps, BPA and CLT would review all data and causal factors to identify potential management actions and make a recommendation for implementation. Following a determination of project success, or the implementation of adaptive management measures to reach project success, the Corps could add this project to an existing program which regularly inspects completed restoration projects. After meeting project goals and objectives, if additional monitoring is warranted it would be funded by non-Federal dollars by the project sponsor (BPA) or land owner (CLT).
4. AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCESThe sections below describe the existing conditions of all human and natural resources that could be affected as a result of implementing the project alternatives described above. The resource descriptions provided below serve as the environmental baseline with which to compare the potential effects of the project alternatives considered in this draft EA. Two alternatives are evaluated in detail: the No Action Alternative and the Proposed Action.
Section 102 of NEPA, as amended, instructs federal agencies to insure that environmental amenities and values be given appropriate consideration in decision-making processes along with economic and technical considerations. For this action, only those resources which would influence the Proposed Action or which may be affected by the Proposed Action were evaluated. Other resources, including hydropower, irrigation, and navigation, were considered but not carried forward for detailed analysis because those resources would not be impacted
by the Proposed Action. The following resources evaluated for potential effects include:
1. Hydrology and Hydraulics
2. Geography and Topography
3. Wetlands and Aquatic Habitats
4. Fish and Wildlife, including Threatened and Endangered Species
5. Water Quality
6. Soils and Sediment Quality
7. Air Quality and Noise Pollution
8. Cultural Resources
11. Climate Change The range of potential environmental consequences are discussed with respect to the context and intensity the No Action Alternative and the Proposed Action would have on each of the above listed resources at the CSR project site. The range of impacts are evaluated as two categories of effects: (1) direct effects, which occur at the same time and in the same place as the action; and (2) indirect effects, which occur later or at a location away from the action.
Baseline conditions are used to evaluate and predict the range of potential effects, both temporary and permanent, resulting from implementing the No Action Alternative or the Proposed Action. The period of analysis for direct and indirect effects begins upon completion of the construction activities when potential benefits may first be achieved (2018) and extends for a duration of 50 years (2068) following implementation. It is assumed that the full extent of effects would be realized within the 50-year planning horizon, at which time, the project would April 22, 2016 Page 20 have reached a state of equilibrium. Cumulative effects are additive and include those effects which occur in the past, present, and reasonably foreseeable future, are discussed in Chapter 5.
As described in Chapter 1 of this document, prior to the conversion of floodplain habitats into agricultural lands, the Columbia River floodplain consisted of a complex mosaic of marsh and wetland habitats, tidal channels and sloughs, swamps and riparian forests supporting natural ecosystem functions and processes. Alterations in the hydrograph coupled with construction of the Columbia River Levee and 100 years of human uses in the lower Columbia River and estuary have fundamentally altered natural habitats and contributed to the evolution of present-day conditions in the lower Columbia River and estuary. For each of the resource categories listed above, the environmental consequences of the No Action Alternative are evaluated under the assumption that no restoration actions are implemented and existing conditions prevail for the duration of the planning horizon (50 years). Environmental consequences under the Proposed Action Alternative describe the state of the project site assuming the restoration actions described in Section 3.2 are implemented as described.
4.1. Hydrology and Hydraulics At RM 75, the Columbia River is in a transitional zone subject to both tidal influences and streamflow generated from upstream runoff in the Columbia basin. Water levels on the mainstem Columbia River are managed most actively by the Corps between May and June to support navigation, downstream fish passage and minimize flooding during high water events.
Table 3 summarizes the flood profile for the Columbia River at the CSR project site at RM 75.4 Table 3: Exceedance Flood Elevations from Columbia River Profiles
In addition to Columbia River flows, local hydrology, and hydraulics at the CSR project site are impacted by the overall drainage network for Deer Island and the historic Columbia River floodplain (see Figure 7). Deer Island, inclusive of the CSR project site, contains three natural conveyance channels: Tide Creek, Merrill Creek and Deer Island Slough. Tide Creek and Merrill Creek drain approximately 30 square miles, consisting of a mix of forested upland and cleared agricultural area. Drainage from this upland area collects at two distinct locations along Hwy 30, flowing under the highway, a frontage road and under a railroad bridge before finally discharging into a diversion channel that carries water south to Deer Island Slough. Merrill Creek flows is discharged into a diversion channel that directs water to Deer Island Slough.
Deer Island Slough is split such that upland runoff is directed south to a tide box before discharging to the Columbia River and locally generated runoff is directed north to a manually operated pump station and a 72-inch gravity outlet with a flap gate.
Elevations in Table 3 were obtained from flood frequency profiles based on storage-frequency relationships, unsteady flow models and engineering judgment. The flood profiles were developed in 1987 by the Corps.