PROCEDURAL GUIDANCE FOR EVALUATING WETLAND MITIGATION PROJECTS IN CALIFORNIA'S COASTAL ZONE
A comprehensive mitigation plan is the most important component of all successful mitigation projects. In formulating a plan, information from the ecological assessment is used to generate appropriate and specific goals, objectives, and performance standards for the mitigation project. This information combined with an understanding of the mitigation attributes and a detailed description of the monitoring program form the core of the mitigation plan. The following list of criteria is intended to assist in the preparation and evaluation of wetland mitigation plans. In addition, a check list to assist in plan review is contained in Appendix A. At a minimum, a comprehensive mitigation plan should include:
Ecological assessment results. The mitigation plan should contain a write-up describing the results, analyses, and information obtained from the ecological assessment of both the adversely affected wetland and the proposed mitigation site.
Goals, objectives and performance standards. The mitigation plan should include clearly stated goals, objectives, and performance standards. The goals are broad statements of the project purpose and expected outcome. The objectives explicitly define the steps necessary to reach each goal. The performance standards state in quantifiable terms the level of each attribute necessary to achieve each objective. Each performance standard must identify: 1) the attribute to be achieved; 2) the condition or level that defines success; and 3) the period over which success must be sustained.
Mitigation project concept drawings and design rationale. The project concept drawings should clearly show the plan, profile, and section views of the project in sufficient detail to demonstrate: 1) how the project fits into the surrounding landscape; 2) what the project area will look like immediately after construction; and 3) what the project area will look like when the project goals are achieved. The mitigation plan should also include a written rationale for the proposed design.
Engineering plans. The engineering plans should include: 1) existing and proposed ground elevation contours at the project site; 2) the location and size of all equipment mobilization and material stockpile sites; 3) the location and size of all buffer zones; 4) identification of all cut and fill locations and quantities; 5) identification of all water control structures including design specifications and operation details (where appropriate); 6) identification of all irrigation systems including design specifications and operation details (where appropriate); 7) detailed descriptions of the location and design specifications of any other structures necessary to execute the project; and 8) the location and identification of all utilities that could affect the project design, implementation, or function.
Soil engineering specifications. The mitigation plan should include technical specifications for any activity affecting the soil of the project site, including: 1) methods for conserving and stockpiling top soil; 2) methods for preventing soil erosion during construction (e.g., sediment curtains); 3) a detailed description of back-fill soil characteristics, including grain-size distribution, percent organic matter, nitrogen content, moisture content, and any other characteristics considered important by the project biologist for the successful establishment and recruitment of plants and animals; 4) engineering properties of the soil including consolidation rates, and shear strength should be provided where important to project success. (Consolidation rates influence the final elevation of marsh back-fill soils, and shear strength may be important for determining the size and/or type of foundation for water control or other necessary structures.)
Comprehensive vegetation specifications. At a minimum, the vegetation specifications should provide information on the salvage of existing vegetation, revegetation methods, and vegetation maintenance. Information on vegetation salvage should include a description of the methods for removal, interim storage, and replanting of all plants displaced during construction. The description of revegetation methods should include: 1) a list of all plant species to be planted, including sources of seeds and/or plant stock and plant sizes; 2) drawings showing the location of all plants in plan and section views. These drawings should show the areal distribution and elevation distribution of all plants; 3) a description of the methods and timing of planting including, plant location and elevation ranges; and 4) where appropriate, irrigation and fertilization schedules. The vegetation maintenance program should contain a description of all necessary maintenance activities, including: 1) where appropriate, irrigation system maintenance schedule; 2) methods and schedule for the removal of exotic species and other routine pest control measures such as the use of pesticides; and 3) guidelines for replanting.
Operations and maintenance plan. Where appropriate, the mitigation plan should include a detailed operations and maintenance plan for any control structure (e.g., tide gates, pumps, or levees). The plan should describe all necessary operations and maintenance activities and the schedule of occurrence. Activities proposed in this plan should be coordinated with the monitoring program.
Concurrent research activities. Where appropriate, the mitigation plan should describe the involvement of scientists conducting concurrent research. The plan should include a description of site accessibility and the constraints and opportunities for research.
An implementation plan. This plan should provide the information necessary to demonstrate there is sufficient scientific expertise, supervision, and financial resources to carry out the proposed project and monitoring program in a specified and realistic time frame. For projects that require operations and maintenance, identification of a responsible agent and sufficient institutional resources to carry out the future operation and maintenance of the project is also required. For large, complex projects the implementation plan should include regular (at least quarterly) updates on project progress, so that the regulatory agencies are kept informed.
A monitoring program. The plan should provide a detailed description of the monitoring program. This description should include, at a minimum: 1) a list of the attributes to be monitored; 2) methods for monitoring each attribute, including monitoring frequency and the location of monitoring stations; 3) a rationale for monitoring each attribute in relationship to the project goals, objectives, and performance standards; 4) a rationale for the inclusion or exclusion of reference sites; 5) a description of how the resulting data will be analyzed and how the level of performance will be determined; 6) identification of how the need for remediation or alteration of project operation will be assessed; and 7) an explicit timetable for the monitoring program including data collection, data analysis, and reporting of results.
A remedial action plan. This plan should identify any potential problems and describe the various actions appropriate for remediation. The plan should include documentation of potential site conditions that could require remediation, and the remedial actions that would be taken if those conditions arise. A remedial action is required when data from the monitoring program indicate the mitigation project cannot meet the established goals in an acceptable time frame without further intervention. Remediation may be necessary to correct a design or implementation problem, or to ensure recovery from a natural disaster.
Mitigation plans can be quite complex. In a regulatory context, it may be most practical to develop one plan that meets all the requirements of the different agencies involved. Although specific requirements may vary among agencies, it is in the best interest of all parties to work together early-on to identify the components that must be included in the mitigation plan. These agencies should also work together during the plan review stage. Agency coordination is especially critical in larger, more complex mitigation projects.
Once an acceptable plan is approved, project implementation should occur as soon as practical. One of the chronic problems relating to compensatory wetland mitigation is the often lengthy delays between adverse impacts and completion of the mitigation project. One way to avoid this problem is to have mitigation precede the adverse impacts. The evaluation of mitigation project performance should begin immediately after implementation is completed (i.e., after all of the necessary construction is completed) and should ultimately continue until sustained success is achieved.
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