Chapter 5 - Mitigation and Monitoring

By the mitigation and monitoring stage of the environmental analysis process (CEQA and/or NEPA), initial impact assessment work has been completed. It has been determined that unavoidable impacts to sensitive natural resources require restoration, creation, or enhancement of the habitats affected by the proposed project. The District Biologist has initiated coordination with resource and regulatory agency staff to determine the extent of concern and controversy regarding the proposed mitigation project. The U.S. Army Corps of Engineers (ACOE) usually has final approval in wetland mitigation projects due to the Section 404 (Clean Water Act) permitting requirements. Mitigation for upland projects, such as oak woodland, fisheries, or endangered species, may involve the California Department of Fish and Game (DFG), U.S. Fish and Wildlife Service (FWS), or National Marine Fisheries Service (NMFS) as the lead approving agency.

In the mitigation development phase of the environmental analysis process, a team effort is initiated to develop project goals and objectives, prepare detailed plans, construct, and monitor the project.

For purposes of this chapter, mitigation activities are defined as any biological activities performed in order to compensate for the impacts of transportation projects. Ecological restoration is another term often used to describe these actions. Activities implemented to minimize biological impacts to species or habitats may also be included. Mitigation activities vary widely. Some of the most common types are:

• creation, restoration, or enhancement of general habitat types (i.e., wetlands, oak woodlands);
• creation, restoration, or enhancement of specific habitat for sensitive species (i.e., elderberry plantings for the Valley Elderberry Longhorn Beetle, nesting habitat for Least Bell's vireo);
• structural modifications for sensitive species (i.e., wildlife crossings, fisheries enhancements, desert tortoise fencing);
• habitat modifications to remove predators for sensitive species (i.e., cowbird trapping); and
• providing funds for habitat creation or enhancement by others in private preserves or mitigation banks.

This chapter will focus on the first two types of mitigation activities since they are the most common and can be complex for medium to large-scale projects.

Biological habitat mitigation is a complex endeavor. This chapter does not attempt to provide a comprehensive guide to all aspects of designing and monitoring a Caltrans mitigation project. There are numerous publications that detail habitat creation and/or restoration. Many of those references are provided in Section 5-3, Suggested References. The reference section also includes a list of professional associations involved in the study of ecological restoration. Many Caltrans biologists maintain memberships with one or more of these organizations. Annual and special focus group meetings provide exposure to current methods and theories in this multidisciplinary field.

Networking with other biologists, landscape architects, erosion control specialists, and others within and outside Caltrans is also a valuable way to gain knowledge about ecological restoration.

Goals. The typical overall goal for habitat mitigation is that the mitigation project will replace the functions and values of the habitat affected by the transportation project. An example of a mitigation goal might be as follows:

Objectives. Objectives are specific sub-components of goals such as the following example:

Specific objectives will be dependent upon the suitability of the proposed mitigation site. Special attention should be paid to the wildlife species for which the habitat is being created. These will be the species affected by the transportation project. If attention is not given to the specific needs of the wildlife species, the mitigation site may only represent the creation of vegetative associations. If the transportation impacts were on nesting habitat, for example, and a vegetative association suitable only for forage is constructed, the mitigation goals will not be met.

Historically, there has been more emphasis on assessment of the functions and values of mitigation sites, through the monitoring process, than assessment of areas to be destroyed by project impacts. Affected areas may be mapped and wetlands delineated. However, the rigor of impact analysis is rarely comparable to mitigation monitoring effort. As a result, the habitat goals of the mitigation site may not be proportional to the actual functions and values of the affected habitat. In order to refine this process and ensure that mitigation matches the project impacts, thorough evaluation of impacted areas should be completed through the Natural Environment Study process. Basic parameters such as cover, density and species frequency should be evaluated in impact analysis as a basis for mitigation site development.

In addition to goals and objectives, a preliminary schedule and budget should be developed in this early stage. Preliminary requirements for the mitigation activity (for example, acreage needed for habitat-scale projects) or the source of funds for banking (State or private), should be identified.

The District Biologist may take the lead in forming an informal or formal Mitigation Development Team (MDT). A formal team is most effective for typical projects. The team represents the various disciplines often required in designing and constructing successful mitigation projects. The team should include the Project Manager, Project Engineer, and representatives from Environmental Planning, Landscape Architecture, Hydraulics, Maintenance, and Construction Programs. The team will focus on translating goals into objectives and developing a conceptual mitigation plan, followed by a detailed project proposal. During this time, the biologist continues as agency liaison for coordinating with the resource and regulatory agency staff. If the project includes any consultants under contract to prepare studies outside the skills of Caltrans staff (hydrology, biostatistics, soil science, fisheries, etc.), these individuals shall also be a part of the team. Although Cultural Resources and Hazardous Waste staff may not be formal members of the team, coordination should be made with these units as a part of the site design process, where appropriate. Resource agency staff should also be team members, although their schedules may only allow for attendance at critical meetings.

The responsibility for preparing a central file for project information is often overlooked. A central project file should be established. All team members should be required to file copies of meeting notes, project plans, consultations, project decisions, etc. in a central location to provide an institutional or corporate memory in case of staff changes on the team.

Since there are no Caltrans policies that clearly describe the responsibilities of a MDT, it is imperative that team member roles are clarified early in the process. The Project Manager must provide approval of the mitigation concept and preliminary budget. The Landscape Architect and other team members may work primarily to address the practicality of translating the concept to reality. Typically, staff from Project Development, Landscape Architecture, or their contractors, prepare project plans for construction.

Whether working as lead, co-lead, or team member, the District Biologist must provide input on the habitat aspects of the proposal. It is imperative that the commitments made in the environmental document are used to direct mitigation design.

For wetland and upland habitat projects, the biologist may provide a proposed plant species list, planting densities and layout, and site elevations to accommodate species requirements. The biologist should also present an aquatic species list, where applicable. Key information about target wildlife species and their habitat requirements is included in the preliminary input to the team. For aquatic habitat projects, detailed information on water depth, riffle to pool ratio, temperature, velocity, and substrate characteristics may be required. When fish passage is an issue, water depths, water velocities, swimming ability of fish, culvert length, and jump heights should be a part of the information supplied by the biologist. For a project that requires modifications in aquatic stream habitat it is imperative that a hydrologist/stream morphologist be involved in the process.

When the District Biologist is not knowledgeable about a particular species or habitat, assistance should be sought from other Caltrans biologists, resource agencies, or a consultant. Proposed designs for wildlife crossings and other structural mitigation should be reviewed by biologists knowledgeable about such devices.

The MDT should analyze the methods available to meet the mitigation goals. Species-specific improvements may involve planning activities such as predator trapping, wildlife crossings and/or fences, or the creation of nesting habitat. Where available, mitigation banks are another option for general habitat mitigation. Caltrans is actively developing mitigation banks throughout the state.

Since habitat restoration, general or species-specific, is one of the most common mitigation activities, the following sections detail considerations to be made in a feasibility study analyzing potential mitigation sites.

The site selection process for mitigation project location includes the following considerations:

• conservation easements as an alternative to right of way purchase;
• avoid purchasing or improving habitat on small isolated sites;
• habitat restoration on lands managed by conservation agencies;
• acquiring sites that are adjacent to other lands that are managed for conservation purposes; and
• developing mitigation banks when appropriate opportunities exist.

Potential mitigation sites should be evaluated regarding physical factors as well as consider future development plans which may affect those sites. Written approval of mitigation site selection by the Project Manager may reduce future conflicts regarding implementation of a site design. Caltrans departments involved in plan review/approval include, but are not limited to, Maintenance; Landscape Architecture; Right of Way and Hydraulics.

The MDT must also consider how mitigation development on prospective sites affect neighboring properties. For example, urban neighbors may have concerns about potential effects of mosquitoes from a wetland development. Rural neighbors may have concerns about effects on agricultural crops by wildlife attracted to a mitigation site.

Onsite mitigation is usually limited to small, low habitat value, mitigation activities. Offsite mitigation usually occurs where large acreage is required. Submissions for suitable sites may be obtained from a variety of sources. Right of Way Program staff may be able to provide a list of excess lands which should be considered for mitigation since no acquisition costs are required. Right of Way agents may know of parcels available in the project area through foreclosures or otherwise. Local, State, or Federal agencies may have lands where mitigation could be implemented with Caltrans under a Memorandum of Agreement or Memorandum of Understanding. All reasonable considerations should be taken into account to select the best mitigation site option.

Mitigation banking may be an option where Caltrans has planned in advance for potential impacts to specific habitat types. Private mitigation banks are also an option that has recently become available for some habitat types. The ACOE has developed a banking agreement procedure which should be used where mitigation for impacts to wetlands and other aquatic resources is involved (ACOE, et al. 1995).

Evaluation of possible sites for project mitigation should focus on habitat considerations, ownership specifics, and acquisition costs. Maintenance of the mitigation site in perpetuity should be fully addressed. Internal agreements with the Maintenance Program should be signed, as appropriate. Where Caltrans is unable to take the responsibility of long-term maintenance, the terms of temporary and permanent site management must be made in writing with any other parties involved.

Team members may benefit from creating a checklist for each project to assure that all important factors are considered at this early stage. Site selection should not be approved until team members have assurance that the site has the potential to meet the project goals. This preliminary investigation should include cultural resources and hazardous waste investigation. Using this process, site selection will match project needs. Onsite and offsite proposals should receive equal scrutiny. The availability of areas within the right of way should not influence the selection process such that an inappropriate site is chosen simply because it is available. Areas within Caltrans' right of way have often been compacted and otherwise altered resulting in areas inappropriate for habitat restoration or creation. Ongoing maintenance activities in the right of way and their potential impacts to habitat restoration are other important considerations, as previously mentioned.

One or more reference data sites should be evaluated in the development of the monitoring plan. A reference site contains the same habitat type and is within the region of the mitigation site. Such sites may be mature habitat and can be used for developing mitigation goals. Some references of early stage habitats may also be assessed to determine interim mitigation site goals. Performance criteria for the project are developed following collection of field data of plant species and/or other aspects at reference sites.

The following list adapted from Rieger and Traynor (1994) shows site factors that should be considered in any evaluation of potential mitigation sites.

General Factors:

Political considerations
Regulatory agency approval
Historical context
Hazardous waste
Resource constraints
Historical/Archeology
Wildlife
Vegetation
Water rights
Human use patterns
Current and ultimate site ownership
Constraints

Easements, rights of entry
Agricultural quarantines

Land use compatibility
Acquisition cost
Site stewardship, short and long-term

Physical Factors:

Hydrology

Groundwater
Surface water

Soil characteristics

Organic matter
Texture
pH
Water capacity

Topography

Elevation
Slope and aspect

Water quality

Biological factors:

Historic evolution of existing vegetation
Habitat values and features
Degree of degradation
Wildlife resources (existing and/or proposed)
Plant species (existing and/or proposed)
Sensitive species (existing and/or proposed)
Vegetation succession
Potential predators, weed species (existing and/or potential)
Habitat buffer zones

Following consideration of site factors, a conceptual mitigation plan, including cost estimates, should be prepared for the selected site. The Project Manager is responsible for providing preliminary approval. The biologist should ensure that the concept and location are acceptable to the Federal Highway Administration (FHWA), if Federal funds are involved in the mitigation.

The regulatory and resource agencies responsible for approving the permit action requiring the mitigation should also approve the mitigation proposal. The conceptual plan should be made available for their review so any important issues can be considered prior to site acquisition or approval. This agency review step would also apply to projects where structures are being designed. The MDT should prepare a written feasibility report, including the conceptual plan and a preliminary budget that includes funding for post-construction monitoring, maintenance, and stewardship costs. The Project Manager is responsible for providing the biologist with final written approval of the plan. Future design changes should also require written approval from the Project Manager. This approval represents an in-house procedure that helps to assure compliance.

Following written approval of the mitigation plan, the MDT leader should direct the team to assemble all required resources for preparing a detailed project design. Detailed design may require input from a wide variety of specialists. Typical areas of responsibility are:

Plant Ecologist: Suitability of the plant species and planting plans for the desired plant community; plant succession; current methods of designing and monitoring ecological restoration projects.

Wildlife Ecologist: Habitat requirements of target wildlife species; field monitoring design and implementation.

Agronomist/Horticulturist: Matching planting techniques to unique site characteristics.

Fisheries Biologist: Habitat requirements of target fish species; field monitoring design and implementation.

Statistician: Statistical aspects of post-construction monitoring; reference site sampling design.

Landscape Architect: Planting design preparation (grading, fill); irrigation; weeding techniques; all aspects of plant establishment and monitoring.

Hydrologist: Hydrodynamics in natural stream and open water systems.

Fluvial Geomorphologist: Specific aspects of stream morphology and evolution.

Erosion Control Specialist: Design and monitoring of erosion control specifications.

Geologist: Suitability of subsurface conditions for proposed grading or filling activities.

Soil Scientist: Determination of soil properties which affect project design, such as texture and water holding capacity.

Civil Engineer: Design of roadways, bridges, water structures, and other similar features.

During the design phase, the MDT may perform and/or direct detailed site studies to collect information for design purposes. These activities may include groundwater monitoring, stream surveys, vegetation inventories, climatic data, and many other types of information.

Projects that involve vegetation planting commonly deal with the following factors at different stages of the site design process (adapted from Rieger and Traynor 1994):

Site Preparation Stage:

Grading and drainage
Weed control, removal of invasive non-native plants
Soil ripping
Soil augmentation
Topsoiling

Seed bank
Over excavation (removing upper soil layer with weed seed)

Erosion control

Plant Materials Selection Stage:

Plant species list

Quantities required
Preferred type of planting stock
Appropriateness to wildlife species involved
Recommended sources of plant material

Localities for collection of materials
Material appropriate to the locality or region (gene pool)
Lead-time required for procurement

Recommended planting time

Planting Design and Layout Stage:

Planting zones
Desired percent composition for plant species
Plant mixes/planting associations
Planting spacing and density
Seed mix and application rate

Irrigation System Design Stage:

Plant species water requirements
Demand analysis

Location of water source

Preferred type of irrigation
Control and monitoring systems
Irrigation schedule

Plant Protection Design Stage:

Vandalism protection
Environmental factors

Staking
Sun protection
Insect protection
Weed control
Fungal protection
Browse protection

The final Plans, Specifications, and Estimates (PS&E) may be prepared by the Landscape Architect and Project Engineer with assistance from the other MDT members. PS&E includes staging, scheduling, specifications, and special provisions of the mitigation construction project.

After project plans have been prepared and/or approved by Caltrans staff or its contractors, implementation of the design becomes the responsibility of Caltrans' Construction Program. Members of the mitigation team will be responsible for advising Construction staff if, during field reviews, they determine that all components of the plan have not been constructed as designed. In some planting projects, the Landscape Architect may serve as the lead in plan development and act as the Resident Engineer in the construction phase.

The Landscape Architect conducts oversight of the landscape contractor and implementation of plant establishment. The plant establishment period is defined as the time when plants are watered, weeded, and otherwise maintained for survival. It may vary from one to three years, depending on the project.

The District Biologist is responsible for developing and implementing a monitoring plan to determine whether the mitigation meets the agreed upon goals and objectives of the project outlined in the environmental document. Monitoring for a minimum of five years is a standard amount of time for general habitat mitigation; however, regulatory agencies often require more time for large, controversial wetland projects. Where wetland habitat is affected, the ACOE guidance entitled Habitat Mitigation and Monitoring Proposal Guidelines should be followed. Each ACOE district has its own version of the guidelines; therefore, the District Biologist should ensure that they are using those guidelines appropriate for their district.

Monitoring habitat mitigation projects is a complex subject. There are diverse opinions as to what activities should be performed, as well as how and when they should be done. There is general agreement, however, that the reason for monitoring is to evaluate the mitigation project in order to take the necessary remedial actions and ensure project success. The District Biologist should work closely with other district and headquarters staff to determine whether the proposed mitigation meets standards set by previous Caltrans work. Regulatory agency requirements far above these informal standards should be scrutinized. Justification should be provided for extensive monitoring proposals.

Post-construction monitoring in ecological restoration will determine whether a site is trending toward development of mature habitat. In addition, valuable information may be obtained to aid in planning and design of future projects. Since monitoring funds are very limited, it is important that the monitoring activities are closely aligned with the original mitigation goals.

Monitoring activities should be clarified to determine if information is being gathered for general purposes or for specific site management. General purpose information includes information that is of interest, but may not be directly connected with managing the site. Monitoring thresholds are an example of a specific site management issue. If a threshold is not met within a certain time, then a specific management action would be performed. For example, if the threshold of 40% vegetative cover of target species is not met at the second year, weeding practices would be modified.

Monitoring may involve the collection of quantitative and/or qualitative data. Specific quantitative criteria may be developed, or qualitative activities, such as photographic documentation, may be used. Many monitoring plans focus entirely on evaluation of vegetation. Plant cover, density, vigor, and species composition are commonly measured. However, there is a trend toward measuring whether the target wildlife species have actually inhabited the mitigation site. Biologists should work with resource agency staff to give full consideration to collecting trend data as an alternative to quantitative performance criteria. If the data show that the project is trending toward habitat development, negotiated resource agency approvals may be obtained.

Annual monitoring reports are prepared by the District Biologist and are submitted to the appropriate regulatory and resource agencies.

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American Fisheries Society
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California Exotic Pest Plant Council
California Native Grass Association
California Native Plant Society
Society for Ecological Restoration
Society of Wetland Scientists
The Wildlife Society