California Coastal Commission

PROCEDURAL GUIDANCE FOR EVALUATING WETLAND MITIGATION PROJECTS IN CALIFORNIA'S COASTAL ZONE

Three case studies were completed in order to evaluate the accuracy and applicability of the procedures for evaluating wetland performance. To identify suitable case studies, a number of past permitted projects that included a wetland mitigation component were reviewed. Upon further investigation, three compensatory wetland mitigation projects were selected: 1) Lone Tree Slide/Bolinas Lagoon, in Marin County; 2) Old Salinas River Channel; in Monterey County; and 3) Sweetwater Marsh Complex, in San Diego County. These projects are representative of the type of wetland mitigation projects the CCC receives, and are geographically distributed over a substantial portion of the coastal zone.

The permit files for each wetland mitigation project were reviewed and summarized. A permit review form was used to facilitate the review process. A checklist form was used to determine the extent to which each mitigation plan included the key elements described in this document. The permit review form and the checklist were designed as tools to assist in the preparation and review of coastal development permit applications including compensatory wetland mitigation projects. Blank copies of these forms are included in Appendix A, while completed forms are included as part of each case study.

Current evaluations of the adversely impacted site and the mitigation site were also completed as part of each case study. These evaluations included field inspection of both the affected and mitigation sites, as well as an examination of relevant aerial photos taken in 1986 and 1993. A field evaluation form was completed for each site during the field inspection. A blank copy of this form is included in Appendix A as well, while a completed form is included as part of each case study. Finally, available monitoring reports were reviewed to determine the appropriateness of the monitoring program and to learn how the mitigation sites have changed over time. Information in the monitoring reports and the field evaluation results were used to judge the current level of permit compliance and project performance.

Each case study begins with a background section, which provides a brief project summary. Following the background is a presentation of project specific information organized by the major elements presented in the general procedures for evaluating wetland performance (i.e., (1) ecological assessment, (2) goals, objectives, and performance standards, (3) mitigation attributes, (4) monitoring program, (5) evaluating performance). In the final section of each case study, the general procedures for evaluating wetland performance are used to highlight the strengths and weaknesses of each project. Based on these analyses, possible modifications to the permit language are described.

10.1. Lone Tree Slide/Bolinas Lagoon Case Study

In January 1991, the Commission approved an application by the California Department of Transportation (Caltrans) to repair a landslide damaged portion of Highway One, south of Stinson Beach in Marin County (Coastal Development Permit 1-90-109). The project resulted in the excavation of the adjacent hillside and subsequent deposition of 201,000 cubic yards of fill into the ocean, covering rocky and sandy intertidal habitat and sandy subtidal habitat immediately below the repair site. Initial deposition and subsequent settling of the fill material resulted in the loss of 5.61 acres of marine habitat. Mitigation was required as a condition of the permit. However, because of the need to repair the road quickly, the CCC expedited the permit process and allowed the preparation and implementation of a compensatory mitigation plan to follow, rather than precede, the repair project. Further, the CCC recognized that "available mitigation sites for in-kind restoration of intertidal or subtidal rocky and beach habitat are limited along the Marin Coast." As a result, "the Commission imposed a condition that allowed some latitude in the development of a restoration plan," to compensate for the direct burial of marine habitat.

The Army Corps of Engineers permit conditions included a requirement that Caltrans coordinate with a multi-agency Technical Advisory Committee (TAC) to develop a mitigation plan for the lost marine habitat. The TAC was composed of staff from fifteen agencies and environmental organizations. Ultimately, a proposal for out-of-kind mitigation at Bolinas Lagoon was recommended by the TAC to fulfill a portion of Caltrans overall mitigation requirement. The Bolinas Lagoon mitigation project (CDP 1-93-07) was approved by the CCC on March 18, 1993. The mitigation project involved the removal of historic fill from two areas in the lagoon, to restore intertidal mudflat habitat and enhance the tidal prism. This project, however, only partially fulfilled Caltrans' mitigation obligation, since only 2.01 acres of lagoon habitat were restored. The remaining 3.6 acres of required mitigation will be satisfied through the restoration of another wetland, Big Lagoon, which is located near Muir Beach, in Marin County. This project is still in the planning stages and will not be addressed in this case study.

10.1.1. Ecological Assessment

Since the Lone Tree Slide site required immediate repairs, no assessment of the impact site (intertidal and subtidal habitat) was performed prior to impact. Thus, the amount and extent of lost habitat and functions are not fully known. However, the chosen mitigation was out-of-kind compensation, so the results of such an ecological assessment could not have been directly applied to the development of appropriate mitigation goals, objectives and performance standards. Instead, a baseline assessment of Bolinas Lagoon was completed prior to construction at the mitigation site. Moss Landing Marine Laboratories produced two monitoring reports in 1992 (MLML, 1992a,b). The reports provide information on species present in the lagoon and state that in areas where there was reduced tidal flushing, there was a reduced density of invertebrates. The Bolinas Lagoon Mitigation Plan produced by Philip Williams and Associates (1992) included information on site analysis, ecological setting, restoration objectives, opportunities and constraints, recommended design, ecological impacts, and the monitoring program.

Additional sampling of nearby reference sites was completed during development of the mitigation plan, to establish the baseline condition for documenting future changes at the mitigation site. This baseline sampling included the collection of information relating to: benthic invertebrates, fishes, birds, mammals, and marsh and upland vegetation. In addition, tide gauges, and channel cross-section transects were established and monitored for characterizing physical baseline conditions.

Information from all of the baseline surveys was used to develop the mitigation plan. From these surveys it was concluded that the most important aquatic community in the study area was the intertidal and subtidal mudflat, whereas the fill areas had minimal habitat value. Therefore, removal of the fill material to increase mudflat habitat and increase the tidal prism was determined to be a "highly positive enhancement of the natural habitat values of the lagoon."

In March, 1993 an assessment of the existing saltmarsh vegetation was performed by Caltrans staff. The purpose of this survey was to identify plant species and determine composition and cover within the existing intertidal marsh zone. This information was used to develop success criteria for the newly created intertidal marsh area after implementation of the mitigation project. This satisfied a permit condition (CDP 1-90-109) that stated success criteria must be established for the saltmarsh portion of the mitigation project, to ensure that the saltmarsh will exhibit species density and diversity similar to the nearby saltmarsh at the same tidal elevation.

10.1.2. Goals, Objectives and Performance Standards

The following goals, objectives, and performance standards were established for the Bolinas Lagoon mitigation project (CDP 1-93-07).

Goal:

Create a habitat that functions in a manner similar to a natural mudflat ecosystem in Bolinas Lagoon.

Objectives:

1. Restore the maximum possible area to intertidal or subtidal habitat

2. Restore the maximum possible tidal prism to the lagoon

3. Restore the natural hydrodynamic functioning of the southern portion of Bolinas Lagoon

4. Encourage the reversal of the process of conversion of mudflats to saltmarsh

5. Encourage the scouring of deep channels as fisheries habitat

6. Remove toxic fill from the lagoon.

Performance Standards:

Create 5.7 acre-feet of tidal prism. This was the only performance standard established for evaluating physical success of the project. Monitoring of select physical attributes (e.g., channel elevations, and water level) was used to determine whether this standard was met.

Although performance standards were required for the intertidal saltmarsh fringe plant community, no other biologically oriented performance standards were developed. Based on the existing saltmarsh vegetation survey completed by Caltrans, two success criteria were projected for the newly graded areas adjacent to Highway One: 1) in five years, the saltmarsh vegetation must be established, with 80 percent cover; and 2) all species that are naturally occurring native saltmarsh species (target species) should be evident at the mitigation site by the end of five years. If these target species are not established, remedial action must be taken, including the removal of invasive exotic species. This remedial action is also a specific condition of the permit (CDP 1-90-109).

10.1.3. Mitigation Attributes

This project is an out-of-kind compensatory mitigation project, since the restored habitat type is different from the adversely impacted habitat type. The mitigation occurred off-site, as there was no appropriate location close to the impact site.

Calculating a mitigation ratio is more complicated because the Bolinas Lagoon project only fulfills a part of the overall mitigation requirement (i.e., restoration of 2.01 acres). The remaining mitigation requirement will be satisfied upon completion of the Big Lagoon mitigation project. This project is expected to create 2.3 acres of wetland habitat and enhance 13.9 acres of wetland habitat. This combination of compensatory mitigation activities at two different sites will fulfill the mitigation requirement necessary to compensate for the loss of 5.61 acres of marine habitat.

10.1.4. Monitoring Program

Monitoring of the mitigation site was a specific permit condition (CDP 1-90-109 as amended). This condition required completion of a five-year monitoring program specifically designed to measure the success of the mitigation project.

Monitoring for this mitigation project includes both a physical and biological component. The biological attributes are monitored by Moss Landing Marine Laboratories, while the physical attributes are monitored by Philip Williams, and Associates. The following attributes are being monitored: benthic invertebrates, fish, birds, mammals, marsh and upland vegetation, tidal height, and channel cross-section elevation.

In a subsequent Commission staff report (1992), it was stated that monitoring the physical attributes was expected to determine the following:

1. the amount of sediment accumulating at the mouth of Stinson Gulch;

2. the presence of obstructions to andromous fish migrating up Stinson Gulch;

3. the change in tidal prism; and

4. the aerial extent of intertidal/subtidal habitat.

Monitoring reports are submitted quarterly; however, data analyses and the performance evaluation are only presented in the annual reports. In December 1994, the CCC received the third quarterly monitoring report (MLML, 1994), which covers the period May 16 through August 10, 1994.

10.1.5. Evaluation of Performance

Ecological monitoring for five years was proposed in the Bolinas Lagoon Mitigation Plan. The plan stated that monitoring would be used to document any changes in the ecosystem after project implementation. However, at present only a qualitative evaluation of the mitigation site is possible based on the quarterly monitoring reports and the site inspection completed for this case study. At present, the mitigation site seems to be functioning well. Benthic invertebrates and birds are present in substantial numbers, while the physical information (e.g., channel cross-section and tide gauge data) suggests the lagoon is functioning as a dynamic and tidally influenced system. However, the most recent quarterly report mentions the presence of French broom (Genista sp.) along the roadside adjacent to the mitigation site. The presence of this invasive, exotic plant should invoke the remedial measures described in the performance standards above. Additionally, the most recent monitoring report refers to "foul and stagnant water" in the restoration area, suggesting a lack of tidal flushing. The annual report is expected to provide additional information.

10.1.6. Applying the General Procedures for Evaluating Wetland Mitigation Project Performance

This mitigation project has many merits, most notable, the mitigation work appears to have resulted in restoration of a mudflat area and stands a good chance of being fully successful. In addition, the use of a technical advisory committee to help determine the most appropriate mitigation and to lead the development of a comprehensive mitigation plan was clearly a benefit to this project. However, a review of the procedures described in this document shows there were limitations to the permit, particularly relating to the goals, objectives, and performance standards. Following are some suggested areas for improvement.

This case study illustrates the temporal loss of resources. The construction-related impacts occurred in 1991, while the remaining mitigation is not scheduled to be completed until 1999, when the construction of the Big Lagoon mitigation project is finished. Although an ecological assessment of the impact site was not completed, it seems clear that the interim loss of natural resources is substantial. It is important to fully consider the potential for temporal loss of resources in determining the type and amount of required mitigation. This is particularly important if the mitigation is allowed to follow the impact. One possible way to deal with this issue in a regulatory context is to stipulate a mitigation ratio that could increase over time. For example, suppose the coastal development permit established an initial mitigation ratio of four to one. If the mitigation project was not completed within, say, five years (not including monitoring) then additional mitigation would be required, elevating the overall ratio to five to one. Lack of completion within three more years would lead to additional required mitigation, again elevating the overall mitigation ratio.

A number of baseline surveys of the mitigation site and surrounding area were completed during the development of the mitigation plan for this project. Together, these baseline surveys appear to have functioned as the ecological assessment in terms of developing a strategy for restoration, and to a lesser extent, in developing the goals, objectives, and performance standards. However, a review of the relevant information suggests the baseline survey information would have been more useful if submitted as a single comprehensive document, rather than several separate studies by three different parties completed at three different times. For example, one of the baseline surveys evaluated habitat quality for both benthic invertebrates and fish and concluded that these habitats could be improved through completion of the mitigation project. Subsequently, these habitats were included as part of the mitigation plan and benthic invertebrates and fish are sampled as part of the monitoring program. Yet performance standards for these biotic attributes are not stated, so it is unclear how the monitoring information will be used. This situation illustrates the need to clearly define a process for integrating all of the information necessary to develop a comprehensive mitigation plan before proceeding to implementation. In the case of the Bolinas Lagoon project, the technical advisory committee could have facilitated the synthesis of information from the baseline surveys.

An examination of the goals, objectives and performance standards illustrates an area where modification of the permit conditions could enhance the overall mitigation project. Increasing the tidal prism is a valid performance standard, since information about this change in hydrology will determine, at least in part, whether objectives 2 – 4 have been met. The tidal prism affects water volume and current speed in the lagoon, which are indicators of the hydrodynamic processes of Bolinas Lagoon. These hydrodynamic processes, in turn, affect the formation of mudflats, channels, and vegetated areas. However, other performance standards exist that, if included, could have allowed for a more comprehensive determination of success. In particular, performance standards could have been included to provide a biological basis for evaluating success. For example, performance standards for benthic invertebrate abundance, shorebird foraging, and shorebird abundance over time all provide information relating to the biological value of the mitigation site. Similarly, the number of fish species and their abundance is an important attribute of the subtidal habitat function and value. Ultimately, a mitigation plan should include performance standards that permit an evaluation of the physical, chemical, and biological attributes important to overall project success.

Table 3 below, lists the goals and objectives stated in the mitigation plan, compared with suggested goals, objectives, and performance standards developed using the information from the baseline surveys and the procedures described in this document.

Several aspects of the mitigation project suggest that concurrent monitoring of nearby reference sites should have been included as part of the monitoring program. First, restoration of Bolinas Lagoon is out-of-kind mitigation. Thus, the ecological assessment consisted of baseline surveys of the mitigation site (before restoration) and the surrounding lagoon. This information was used to develop an appropriate mitigation plan including establishment of the project goals, objectives, and performance standards. Second, the surrounding natural lagoon provides highly appropriate reference sites, so the performance standards could have been linked to the functional level of the adjacent natural lagoon. Establishing the performance standards in this way would provide a mechanism to account for the ongoing natural variability present in the area, resulting in more accurate and realistic evaluations of performance.

Although it is too early to determine the ultimate success of this mitigation project, it does appear the project has a good chance of achieving the stated goals, objectives, and performance standards. More importantly, the site has the potential to provide sustainable, high quality wetland habitat. Yet, as Table 3 illustrates, the determination of project success is largely based on the establishment of physical features and processes. Thus, a full assessment of the biological functioning is not assured. All of the interested parties could benefit from such an assessment.

Table 3. A Comparison of the Goals, Objectives and Performance Standards for the Lone Tree Slide/Bolinas Lagoon Project¹⁵

CHECKLIST OF INFORMATION INCLUDED IN THE PERMIT FILE AND THE MITIGATION PLAN FOR THE LONE TREE SLIDE/BOLINAS LAGOON MITIGATION PROJECT

LONE TREE SLIDE/BOLINAS LAGOON PERMIT FILE REVIEW

Mitigation Attributes:

LONE TREE SLIDE/BOLINAS LAGOON MITIGATION SITE EVALUATION

Project Information:

Habitat Characterization:

10.2. Moss Landing South Harbor Case Study

In 1988 The Moss Landing Harbor District (hereafter referred to as the Harbor District) applied for a coastal development permit to construct a 1,300 foot-long bulkhead along the west bank of the south harbor, near Sandholdt Road in Moss Landing. The proposed construction involved the placement of 5,500 yards of rock rip-rap for shoreline protection, along with associated demolition, dredging, fill, and spoils disposal. As proposed, the project would adversely affect approximately 0.35 acre of mudflat habitat. The project was determined to be consistent with the Coastal Act and a coastal development permit (CDP 3-88-47) was issued. However, the CCC required the Harbor District to submit a mitigation plan to compensate for the adverse impacts from the bulkhead construction. The permit conditions included several specific requirements regarding the mitigation plan, which are discussed later in this write-up.

In June 1988, a "stop work" order was issued to the Harbor District by the CCC for unauthorized grading and filling of a wetland along the Old Salinas River just south of the bulkhead site. Specifically, three acres of old dredge ponds and adjacent berms were re-graded in order to level the area. Additionally, several truckloads of trash were removed from an area occupied by transients. This activity was considered a violation because no coastal development permit or Section 404 permit had been issued for this work, as required by the Coastal Act and the Clean Water Act respectively. The Army Corps of Engineers (COE) determined that 1.4 acres of the graded area had been jurisdictional wetland under Section 404 of the Clean Water Act. Subsequently, all activities related to the bulkhead project were suspended in June 1988. In order to resolve this violation and complete construction of the bulkhead, the Harbor District was required to mitigate for the unauthorized activities by fully restoring the lost wetland habitat. In addition, the site of the unauthorized activities was identified as a possible mitigation site for the adverse impacts associated with the bulkhead construction.

In 1989, Jones and Stokes Associates completed the Moss Landing Harbor Wetland Mitigation Plan. This plan proposed compensatory mitigation for the loss of 0.35 acre of mudflat habitat at the bulkhead site and mitigation (via restoration) for the unauthorized filling of 1.4 acres of jurisdictional wetland. Mitigation for both activities was proposed to occur at the unauthorized fill site adjacent to the Old Salinas River. The mitigation plan addressed the conditions of the coastal development permit, outlining the proposed restoration activities at the fill site. The mitigation plan was approved in October 1989. In 1990, the Habitat Restoration Group completed the Revegetation and Monitoring Program for Moss Landing South Harbor Restoration Project, which further described the activities proposed at the mitigation site. This report also outlined the monitoring program that would be used to document mitigation project performance.

10.2.1. Ecological Assessment

Relatively speaking, a great deal of work was completed to assess the functions and values of both the adversely impacted and the mitigation sites. Between 1985 and 1989 four separate studies were completed, each of these is described below.

In 1985, an intertidal invertebrate study was completed as part of the application process for the coastal development permit to construct the bulkhead (Fukuyama, et al., 1985). For this study both sites in the project area and adjacent control plots were sampled concurrently in order to compare the habitat quality of the proposed bulkhead site to adjacent natural intertidal areas. This study found that the area was extensively modified by human activities and contained relatively few invertebrates. Additionally, an environmental assessment of the proposed bulkhead site was performed by the Army Corps of Engineers (COE, 1988), in which the potential effects to the construction site were described. The assessment determined the elevation and substrate composition of existing subtidal and intertidal habitat would be altered, and there would be an increase in turbidity in the affected area. The bulkhead construction activities were anticipated to adversely affect the intertidal mudflats, and result in the loss of aquatic habitat important to estuarine and invertebrate species.

One of the coastal development permit conditions required "a pre-construction survey of intertidal habitat to be lost" (CDP 3-88-47). In 1988 an expanded initial study was conducted for the bulkhead site (John Gilchrist and Associates, 1988). Field sampling characterized the proposed bulkhead site as rocky to silty-sand substrate with accumulations of human generated debris. This report included an invertebrate study, which concluded that "although diversity was relatively high, low species density indicates that this is not high quality habitat." Further, this report concluded that adverse impacts to the benthos and the fish would occur as a result of the increased sedimentation and turbidity in the construction area. Meanwhile, the proposed dredging would result in the direct burial of benthic organisms. No ecological assessment of the violation site was performed prior to the unauthorized grading and filling activity.

The Mitigation Plan (Jones and Stokes, Associates 1989) provided a characterization of the affected areas, and described the condition of both the bulkhead and the unauthorized fill sites prior to impact. The pre-impact conditions at the unauthorized fill site were generally described as having contained areas of undisturbed tidal saltmarsh and moderately disturbed marsh and upland. Common plants at the site included pickleweed, saltgrass, and other marsh vegetation. This compliment of vegetation remains in relatively large areas of high quality saltmarsh immediately south of the violation site and elsewhere in the vicinity. Common mammals and birds likely to have used the site were also listed. Overall, characterization of the bulkhead site in the mitigation plan concurred with earlier ecological assessments of the intertidal habitat, although a discontinuous band of disturbed saltmarsh and upland vegetation was also reported to exist at the bulkhead site.

10.2.2. Goals, Objectives, and Performance Standards

A single ecological assessment of the adversely impacted and mitigation sites was not completed. However, results of the four studies described in the section above provide comparable information that was used to develop the goals, objectives and performance standards for this mitigation project.

The goals for this project are best described in the 1990 report, written by the Habitat Restoration Group:

1. To establish salt marsh vegetation on the project site that is virtually and ecologically similar to the adjacent undisturbed areas.

2. To begin a process of succession that will result in habitat and wildlife values similar to neighboring undisturbed saltmarsh areas.

3. To return the area to a stable ecosystem which will require no further human input once the vegetation has been established.

The objectives for the project are clearly stated in the 1989 Mitigation Plan written by Jones and Stokes Associates:

1. Restore approximately 1.4 acres of saltmarsh habitat in the area impacted by grading and fill deposition. The restored saltmarsh would provide one to one compensation (on an aerial basis) for the fill material deposited in the wetland.

2. Create at least 1.05 acres of tidal mudflat habitat in the area disturbed by grading. The new mudflat would provide three to one compensation for the filling of approximately 0.35 acre of mudflat at the proposed bulkhead site.

3. Create wetland habitat values at the mitigation site that are equal to or greater than those lost at both sites. Net increases in habitat values could compensate for temporary losses in wetland values over several months.

4. Re-create and improve the upland buffer around the restored wetlands. Upland buffers would provide refuge for saltmarsh animals during periods of high water and would reduce disturbance to wetland wildlife from activity in surrounding developed areas.

Performance standards "to determine successful revegetation of the area and a plan outlining where, when, and how additional areas would be enhanced if the mitigation was not successful" were required in the coastal development permit. The mitigation plan (Jones and Stokes Associates, 1989) provided specific performance standards:

1. Mudflats: Mudflats in the mitigation area should remain largely unvegetated, open to daily tidal flows from the Old Salinas River, and free of ponded water during low tides. Within 2–5 years after completion of grading, mudflats in the mitigation area should achieve an appearance and level of shorebird use similar to those of mudflats in the old Salinas River.

2. Pickleweed Marsh: Natural establishment of pickleweed should be evident on the marsh plain area within one year after grading is completed. Significant increases in pickleweed cover should be evident in each succeeding year. After five years, vegetation in the pickleweed marsh should be dominated by pickleweed and have achieved (or exhibit a trend toward) percent cover that is comparable to that in undisturbed pickleweed marshes along the Old Salinas River.

3. Saltgrass Marsh: Survival and establishment of saltgrass should be evident in planted areas within two months after planting is completed. Significant increases in saltgrass cover should be evident in each succeeding year. After five years, vegetation in the saltgrass marsh should be dominated by saltgrass and have achieved (or exhibit a trend toward) percent cover that is comparable to that in undisturbed saltgrass marshes along the Old Salinas River.

4. Peripheral Upland: Survival and establishment of upland plants should be evident in planted areas within 2 months after planting is completed. A significant increase in upland plants should be evident in each succeeding year. After five years, vegetation in the upland should be dominated by native shrubs and provide substantial visual screening from nearby buildings, yards, and human activity.

The mitigation plan (Jones and Stokes Associates, 1989) also described the remediation requirements if these standards were not met:

1. Mudflats: If significant ponding or blockage of the slough entrances occurs, the slough channels will be deepened or otherwise modified as necessary to improve the flow of water. If the mudflats do not function similarly to those in the Old Salinas River after five years, the performance standards will be reassessed and other remedial actions may be identified in consultation with COE and other commenting agencies.

2. Pickleweed Marsh: If natural establishment of pickleweed is not evident within one year and if habitat conditions appear suitable for this species, seed-bearing stems will be collected from a nearby marsh and scattered throughout the area intended for pickleweed establishment. If annual increases in pickleweed cover appear to be inadequate, soil salinity, fertility, and moisture conditions will be examined and fertilizers or freshwater irrigation will be applied, if necessary. If pickleweed cover is inadequate and does not exhibit an increasing trend after five years, the performance standards will be reassessed and other remedial actions may be identified in consultation with COE and other commenting agencies.

3. Saltgrass Marsh: If saltgrass plantings fail to survive in portions of the planted area, additional plugs or transplants will be planted to replace those lost. If annual increases in saltgrass cover appear to be inadequate, soil salinity, fertility, and moisture conditions will be examined and fertilizers or additional irrigation will be applied, if necessary. Additional plants of other native species appropriate to this habitat may be planted. If saltgrass cover is inadequate and does not exhibit an increasing trend after five years, the performance standards will be reassessed and other remedial actions may be identified in consultation with COE and other commenting agencies.

4. Peripheral Upland: If upland plantings fail to survive in portions of the planted area, additional plants will be planted to replace those lost. If annual increases in cover appear to be inadequate, soil salinity, fertility, and moisture conditions will be examined and fertilizers or additional irrigation will be applied, if necessary. Additional plants of other native species appropriate to this habitat may be planted. If visual screening is inadequate and does not exhibit an increasing trend after five years, the performance standards will be reassessed and other remedial actions may be identified in consultation with COE and other commenting agencies.

Additionally, the 1990 report by the Habitat Restoration Group stated "a success criteria of 90 percent survival after one full year of growth after installation shall be established for all installed plants." This applies to all the plant types mentioned above.

10.2.3. Mitigation Attributes

Mitigation for all adverse impacts occurred at the unauthorized fill site. The mitigation plan stated that "combining restoration of the two different habitats at one location will provide a more complete and diverse ecosystem that is expected to have higher habitat qualities than either impact area prior to disturbance." Combining these two mitigation requirements on one site seemed the most logical approach, given the type and proximity of the adverse impacts and the land ownership of the harbor district. However, this decision necessitated a mitigation plan that provided in-kind mitigation for both vegetated saltmarsh and mudflat habitats at a single site. The approach described in the mitigation plan was "to excavate most of the disturbed area [the unauthorized fill area] to elevations below pre-disturbance levels to increase the amount of tidally influenced low saltmarsh and mudflat habitats. Some existing uplands would be converted to wetlands by ... excavating part of the upland at the north end of the site." Thus, partial restoration of the saltmarsh and partial conversion to provide mudflat habitat occurred in an area that had previously existed as vegetated saltmarsh. In addition, some new wetland habitat was created in previously upland areas. This suggests the overall project included some wetland restoration, some wetland conversion (considered enhancement) and some wetland creation.

A condition of the coastal development permit required a "mitigation site replacing lost intertidal habitat with like habitat at a 3 to 1 ratio." Therefore, the 0.35 acre of mudflat lost at the bulkhead site required 1.05 acres of mudflat habitat as mitigation. In fact, the mitigation project resulted in 1.1 acres of mudflat habitat, yielding a final mitigation ratio of approximately 3.1 to 1. Mitigation for the 1.4 acres of saltmarsh impacted by the unauthorized grading and fill yielded a 1 to 1 mitigation ratio. The combined mitigation ratio was somewhat greater than 1 to 1 and resulted in a net increase of mudflat habitat, although at the expense of vegetated saltmarsh habitat (Table 4).

Table 4. Summary of Applicable Acreage Values and Resulting Mitigation Ratio for the Moss Landing South Harbor Mitigation Project

Another condition of the coastal development permit was that "mitigation project construction occur concurrently with the bulkhead project." This is an important consideration, because it minimizes the temporal loss of wetland habitat. Although settlement of the unauthorized activities delayed both the mitigation and bulkhead work, eventually all work did proceed concurrently.

10.2.4. Monitoring Program

An additional condition of the coastal development permit was that "a five year monitoring program with annual reports, prepared by a qualified biologist, be submitted to the Executive Director and the Department of Fish and Game." The mitigation plan stated that monitoring will "evaluate whether the restored habitats are progressing toward the mitigation objectives." The Habitat Restoration Group's (1990) report stated that "the goals of the monitoring program are to measure success of the [mitigation] project, to evaluate the extent to which restoration of an entire ecosystem is established, and to determine additional needs or inputs, such as replanting, or controlling undesirable plants..."

The mitigation plan suggested the following monitoring program, with vegetation as the primary attribute of the monitoring activities. Vegetation cover and composition throughout the site would be recorded at two month intervals for the first year, then twice a year for the next four years. The locations of naturally establishing pickleweed will be mapped. The identity and relative abundance of all plants will be recorded. Plant composition and percent cover will be surveyed in ten permanent 1-meter square vegetation plots. Potential problems that may require remediation will be monitored, such as erosion, or failure of plants to become established. As previously mentioned, the mitigation plan provided specific requirements for remediation should the mudflat, pickleweed, or saltgrass habitat fail to become established. The monitoring reports were expected to document when these remedial measures should be considered. The monitoring program also included periodic monitoring to determine the species richness and abundance of birds and benthic fauna at the mitigation site over time.

10.2.5. Evaluation of Performance

Unfortunately, assessing this project on the basis of the monitoring reports does not provide a complete understanding of the condition of the mitigation site. Monitoring reports for the first two years, 1991 and 1992, were produced by The Habitat Restoration Group. ( A discussion of the results of these two reports will follow.) Monitoring of the site was interrupted after 1992 due to procedural difficulties within the Harbor District in establishing a new contract for monitoring. Assegued and Associates was ultimately awarded the monitoring contract and submitted a progress report in 1994; however, the third annual monitoring report is still pending. Monitoring is expected to continue at least until 1996, unless remedial action is taken, which could extend the monitoring program.

The goals and objectives of this project suggest the mitigation site will be restored to a condition similar to the adjacent natural marsh. These goals indicate that concurrent monitoring of both the mitigation site and adjacent reference sites is necessary. The 1991 monitoring report documents the monitoring of control plots for just such a purpose. Bird surveys were completed at both the mitigation site and adjacent control sites. Benthic invertebrates were sampled at the mitigation site and control sites across the channel. The same comparison with a reference area (i.e., undisturbed marsh habitat) was to occur for the vegetation monitoring as well; however, no reference site information is presented in any of the reports on file.

The appendix of the Habitat Restoration Group's report (1990) characterizes bird usage at the mitigation site based on the preliminary results of bird monitoring. It is concluded that "waterbird species richness on the [mitigation] site is greater than elsewhere along the Old Salinas River." These results are corroborated in the 1991 monitoring report (The Habitat Restoration Group, 1991). This monitoring report also states that the abundance of benthic organisms on the mitigation site approximates abundance levels documented in nearby control sites. The 1992 monitoring data for shorebirds indicates the mitigation site has high habitat value as a forage area for birds (The Habitat Restoration Group, 1992). While results from the 1994 progress report (Assegued and Associates, 1994) for these two biotic attributes are inconclusive, the CCC staff's site evaluations in December 1994 and February 1995, corroborated earlier findings that the restored mudflat provides good habitat for shorebirds.

No trend is evident in the establishment of vegetation at the mitigation site. The first monitoring report in 1991, does not present vegetation data recorded at two month intervals, as stipulated in the 1990 mitigation plan. Only four data sets are available between May 1990 and June 1991. This data shows that while some areas of the mitigation site have relatively high vegetation survival rates and recruitment, the southern portion of the site experienced die-off and slower rates of growth. Thus, at least some areas of the mitigation site did not meeting the 90 percent success criteria for installed plants. These results may be due to the presence of unsuitable substrate, specifically the dredge spoil material used to construct portions of the site.

The 1991 monitoring report states that "no plant or natural species recruitment occurred during the first year on the east–west arm extending towards the Old Salinas River. The absence of any species colonization in this area is difficult to explain." These statements suggest the project was not performing as expected, and raises concerns for condition compliance. This type of information should trigger staff investigations into remediation.

In 1992 the vegetation monitoring regime was changed. As a result, the vegetation data was analyzed on a community level basis rather than a species specific basis as presented in the 1991 monitoring report. These differing methodologies prevent direct quantitative comparisons between years. The 1992 vegetation data indicates a relative increase in plant cover and establishment. In some areas, however, much of the increase in plant cover can be attributed to non-native species, which suggests a decline in habitat value. Overall, it was concluded from the 1992 monitoring data that no additional work in the vegetated areas, other than weeding, would be required. Although the associated vegetation data seems to support this conclusion, the CCC staff's site evaluation in December 1994 (see attached form), raises questions about the validity of this conclusion.

The 1994 progress report (Assegued and Associates, 1994) states that vegetation at the mitigation site shows "very high survival rates throughout the restored site... Overall almost complete coverage of the restored area by native species was noted..." However, both the CCC staff's site evaluation and aerial photos taken in 1993, show that significant portions of this site lack vegetation. This is partially due to the presence of an incised channel, which was first reported in the 1992 monitoring report. By 1994, the incised channel had created a mudflat island of the "arm" extending toward the center of the Old Salinas River. A subsequent site inspection by CCC staff in February 1995 showed the incised channel had deepened and widened with the previous winter storms, and tidal currents appear to have further eroded the newly formed mudflat island. The absence of vegetation on this island and surrounding mudflat areas was evident during the site visit, and is not consistent with the expected vegetation distribution described in the revegetation plan. In addition, an ongoing transition of intertidal to subtidal habitat appears to exist, which is also not consistent with the expected habitat distribution.

10.2.6. Applying the General Procedures for Evaluating Wetland Mitigation Project Performance

This mitigation project has many merits and includes many of the features necessary for a project to achieve a high degree of success, as described in this guidance document. For example, this project had an ecological assessment of the bulkhead site prior to impact, and a habitat characterization of the unauthorized fill site. This information relates to the habitat functions and values that require mitigation, and is reflected in the goals, objectives, and performance standards. The mitigation attributes of this project address the need to compensate for lost habitat either by increasing the ratio, or by directly compensating for the resources through on-site restoration of in-kind habitat. In addition, interim losses of wetland habitat were minimized through a permit condition that required the mitigation to be completed concurrent with the bulkhead construction. The monitoring program was designed to determine whether the performance standards have been met, and if the mitigation site is progressing toward functional equivalency with the adjacent natural saltmarsh.

The permit conditions and the mitigation plan provided for remediation if necessary. The monitoring reports were intended to document any potential problems at the site that may require remediation. However, despite these permit conditions and the regulatory actions required for the associated violation, the CCC did not require remediation when the site failed to perform as expected. The apparent change in hydrology at the site, which has resulted in a deep incised channel and a relative increase in unvegetated area, should have been addressed in 1992 when it was first described in the monitoring report. The coarse fill material, which appears to have precluded the establishment of vegetation in certain areas of the site, could have been amended with more appropriate material. These features could have been addressed more directly if there had been performance standards for the physical and chemical attributes of this project. For example, a performance standard for the sediment could have read: sediment composition at the mitigation site must achieve (or exhibit a trend toward) the composition of sediment found in nearby reference site within five years.

The resulting functions of the mitigation site are largely a product of the project design. In retrospect, however, it appears that it was inappropriate to create mudflat habitat in an area that was historically vegetated saltmarsh. The continued habitat instability at the site, marked by enlargement of the incised channel and erosion of the intertidal mudflat, are direct evidence of habitat incompatibility. The mitigation plan recommended grading the marsh plain below the elevations considered optimal for developing mudflat and saltmarsh habitats, to accommodate the natural siltation expected to occur. Although sediment accumulation has not been measured, by all accounts it does not appear that the expected siltation is occurring at the mitigation site. In addition, The anticipated hydrology described in the mitigation plan has not developed at this site, with the resulting hydrology giving rise to the apparent habitat instability.

The concerns over creating mudflat habitat in a historic saltmarsh are discussed by ABA Consultants (1992), who state that "the [Moss Landing South Harbor] mitigation plan was developed by an environmental consultant without regard for the best local and regional wetland restoration needs... Sandflat and channel habitat were created by digging into an historical and degraded pickleweed marsh... A large hole in the marsh was eroded by tractors in several weeks, adding to the overall loss of this natural habitat... The resulting channels are now being enlarged by tidal and wave action and even more of the wetland is being eroded. Nature constructed lush vegetated marshes along the channel of the old river, this is the obvious habitat to restore and enhance." These statements emphasize the need for all mitigation project proponents and reviewers to consider the landscape setting of the mitigation project.

This case demonstrates that despite CCC staff's best intentions to write a permit with conditions that would improve the mitigation project's chances for success, the fundamental requirement for ecological soundness cannot be overlooked. The lack of follow-through with appropriate remedial action, which was stipulated in the permit and the mitigation plan, only further compounded the difficulties associated with the mitigation project. Although the monitoring reports do not provide a clear assessment of performance in relation to all established standards, there were indications the overall project was not on a path to achieving the stated goals. Yet the project proponent continued to act in good faith, making an effort to comply with the permit conditions. This is an awkward position for CCC staff: at what point should the regulatory agency require remediation or substantial change to a mitigation project that may not be working? Unfortunately, no general response to this question exists. The answer will largely depend on the specific project. In the case of this project, there were direct indications of local concern as early as 1992 (e.g., ABA Consultants, 1992). These concerns should have been enough to alert CCC staff to a potential problem. Meetings with the concerned individuals and the project proponent could have served as a forum for developing appropriate alternatives.

This case study illustrates how specific procedural and ecological factors yield a situation that deviates from the "ideal process" described in this document. However, this case study provides useful guidance to future projects: 1) a realistic and appropriate project design is as important as any other element of a mitigation project; and 2) follow-through is critical to achieving success. The key here is that appropriate monitoring and remedial action must be undertaken if the site is not performing as expected, or not progressing toward the goals; in this case, the restoration of an ecologically similar saltmarsh ecosystem. Although the high abundance of birds at the mitigation site exceeds the applicable performance standard, the goal was to restore mudflat and saltmarsh habitats that are ecologically similar to adjacent habitats. That goal remains unfulfilled.

CHECKLIST OF INFORMATION INCLUDED IN THE PERMIT FILE AND THE MITIGATION PLAN FOR THE MOSS LANDING SOUTH HARBOR MITIGATION PROJECT

MOSS LANDING SOUTH HARBOR PERMIT FILE REVIEW

Mitigation Attributes:

MOSS LANDING SOUTH HARBOR MITIGATION SITE EVALUATION

Project Information:

Habitat Characterization:

10.3. Sweetwater Marsh Case Study

The background information for this project is quite extensive, due to the complexity of the mitigation and the numerous agencies involved. The core of the development project included the California Department of Transportation's (Caltrans) expansion of the Interstate 5 and highway 54 interchange, and the U.S. Army Corps of Engineers (COE) construction of a flood control channel on the Sweetwater River. As originally proposed, the development project prompted concerns by the Fish and Wildlife Service (FWS) of potential adverse impacts to species protected under the federal Endangered Species Act (ESA). Since a federal agency (i.e., the COE) was involved, the FWS initiated consultation and project review under Section 7 of the ESA. In 1978, the FWS issued its first biological opinion¹⁶, which found the proposed highway and flood channel project would likely jeopardize the continued existence of two endangered bird species, the California least tern (Sterna antillarum browni) and the light-footed clapper rail (Rallus longirostrus levipes).

Subsequent consultations between the COE and the FWS resulted in two additional biological opinions (issued in 1979 and 1981) and a biological assessment (issued as a draft in 1980). Among other things, these documents proposed various modifications to the overall project that would reduce the adverse impacts to the species of concern. Through the consultation process the FWS ultimately concluded the following:

In reviewing the lengthy consultation, the [FWS] found that the implementation of eleven features were the minimally acceptable loss compensation requirements needed to protect and maintain habitat and endangered species. These features constituted the reasonable and prudent alternative. The eleven features included:

1. Acquisition of 188 acres of wetlands and adjacent buffer zones.

2. Creation of 9.6 acres of wetlands along the southwest portion of the "D" Street fill.

3. Restoration of approximately 25 acres of wetlands in the areas known as the connector marsh.

4. Avoidance of impacts to the California least tern nesting colony.

5. Initiation and completion of all loss compensation features prior to impacts.

6. Maintenance of the tidal connection to Paradise Creek during all phases of construction.

7. Provision of sufficient freshwater inflows for the life of the project to maintain the biological integrity of the wetlands.

8. Modification of the project design to avoid impacts to wetlands.

9. Design of project recreational features to be subject to a subsequent consultation.

10. No construction within endangered species habitats would occur during the nesting season of the endangered birds.

11. All compensation features reviewed and monitored by agency biological staff and continued coordination on all aspects of the project affecting endangered species.

Thus, the Section 7 consultations and related work resulted in expansion of the overall proposed project to include development (i.e., construction of the highway interchange and the flood control channel), and activities considered beneficial to the wetland (i.e., wetland creation, restoration, enhancement and preservation). As a result, the CCC found that the overall project was consistent with the Coastal Act because the benefits to the Sweetwater Marsh complex were substantial enough to characterize the project as wetland restoration,¹⁷ an allowable use of wetlands under Section 30233(a)(7). Consequently, a coastal development permit (CDP 6-83-319) was issued in June, 1983. This permit authorized the first phase of the project: the deposition of fill material for construction of a temporary detour route for Interstate 5. The permit conditions required removal of the fill material and restoration of the area to marsh habitat within six years. Additionally, the permit conditions required, within the same time frame, completion of a plan for the restoration of 10.6 acres of previously filled wetlands. The permit stipulated that "the plan shall provide for the habitat most appropriate to the Sweetwater Marsh complex as determined in consultation with the California Department of Fish and Game, and the U.S. Fish and Wildlife Service." The conditions also required the acquisition and dedication of additional wetland habitat, as specified in earlier documents.

In 1984, the CCC issued another coastal development permit (CDP 6-84-50), which authorized the subsequent phases of the highway and flood control channel construction, as well as the additional marsh restoration and acquisition features stipulated in the FWS's 1981 biological opinion. Although the construction and restoration activities were to occur concurrently, the CCC considered the overall project wetland restoration based on: 1) the acquisition and preservation of 188 acres of wetland habitat and associated buffer areas; 2) modification of 25 acres of the marsh complex; 3) conversion of 9.6 acres of upland to marsh; and 4) acquisition of 10.6 acres of the "D" Street fill area for California least tern nesting habitat. Originally, 9.6 acres of the acquired "D" Street fill area was to be converted back to wetland habitat. Instead, the entire parcel was designated as California least tern nesting habitat, so an alternative site for habitat conversion was required. Eventually, it was agreed that 17.1 acres at the eastern end of the "D" Street fill area, a site located some distance away from the least tern nesting habitat, would be converted from upland to wetland.

In 1985 the FWS became concerned over "the foreseeable impacts to the compensation lands due to construction of the road" without completion of the required land acquisition and transfers. As a result, the FWS formally requested reinitiation of Section 7 consultation; however, the COE refused. This prompted the Sierra Club and League of Coastal Protection to "file a complaint under the citizen suit provision of the ESA," asserting that the "COE had violated the act by refusing to reinitiate consultation with the FWS" (FWS, 1988). Subsequently, the plaintiffs "sought a preliminary and permanent injunction prohibiting further construction on the project" until the land transfer occurred "and a preliminary and permanent injunction against construction until consultation with the FWS was reinitiated and completed" (FWS, 1988). As a result of this legal action, Section 7 consultation was reinitiated in 1987, and the resulting biological opinion (FWS, 1988), is currently followed by the COE and Caltrans for permit compliance. The 1988 biological opinion dealt with the "effects of the subject construction on three endangered species of birds (California brown pelican, Pelicanus occidentalis californicus; California least tern; and light-footed clapper rail) and one endangered plant (Saltmarsh bird's-beak, Cordylanthus maritimus spp. maritimus)." This biological opinion is significant in that it describes the potential effects, outlines alternatives to construction that are designed to minimize or avoid the adverse impacts to listed species, and describes success criteria for the Sweetwater Marsh project.

Utilization of the adaptive management process is an important feature of this project. The adaptive management process has guided both the monitoring program and the performance evaluation. Although this approach was not required, it evolved out of the unique relationship between the project proponents and the Pacific Estuarine Research Laboratory (PERL), which was hired to complete the compliance monitoring. Early on, PERL became highly committed to the project and has subsequently secured outside funding for numerous complementary research projects. The long-standing commitment of PERL, combined with the willing participation of the agency biologists and establishment of a technical advisory group have resulted in successful application of the adaptive management process.

10.3.1. Ecological Assessment

Sweetwater Marsh is a tidal saltmarsh. The marsh is bounded by Interstate 5 on the east side, by the "D" Street fill area on the western and southern edges, and the marsh connects with San Diego Bay along its northern boundary. The first assessment of pre-construction conditions was conducted in 1981 (Caltrans, 1981). This report provided information on the quality of the vegetation, describing the species composition and distribution. The report states that habitat diversity was limited, and that cordgrass was conspicuously absent from the low marsh areas. Much of the study area had previously served as a sanitary fill site, which precluded the development of low marsh. Faunal surveys documented a moderate diversity of invertebrates, fish, birds, and mammals. The primary focus of the Caltrans report was characterization of the distribution, abundance and anticipated effects to the light-footed clapper rail and California least tern. This report additionally provides information on proposed restoration concepts, and mitigation alternatives.

The final biological opinion (FWS, 1988), provides an extensive review of the biological resources and habitat value of the Sweetwater Marsh complex. This report provides a baseline of environmental conditions of the wetland complex, and states that the fragmentation of habitat is a substantial factor when cumulative impacts are considered. The report describes the potential impacts to the California least tern, the light-footed clapper rail, and saltmarsh bird's-beak, as well as the various options available to mitigate the potential impacts. (Impacts to the California brown pelican were not described, and apparently were not pursued.) The adverse impacts included: 1) direct loss and fragmentation of wetland habitat; 2) degradation of water quality; 3) increased human activity; 4) cumulative adverse impacts from adjacent development; and 5) increased predation pressure. This information formed the basis for the project goals, objectives, and performance standards.

10.3.2. Goals, Objectives, and Performance Standards

The goals, objectives, and performance standards described in this case study are based on the FWS's 1988 biological opinion, and not a mitigation plan, as would be expected. The coastal development permit files do not include a formal mitigation plan, but the conditions found in the coastal development permits were addressed by the subsequent biological opinion (FWS, 1988). Thus, project success and permit compliance are assessed based on the performance standards stated in the biological opinion (FWS, 1988). The following goals, objectives, and performance standards are taken directly from the 1988 biological opinion¹⁸:

Goals:

1. Create a 17.1 acre functional wetland containing low, middle and high saltmarsh from existing uplands on the eastern end of the "D" Street fill area.

2. Modify approximately 25 acres of high saltmarsh in the area of the connector marsh to functional low, middle, and high saltmarsh.

Objectives:
The design of the wetland creation and modification projects shall include:

1. Tidal channels to provide foraging for the California least tern and light-footed clapper rail.

2. Low and middle saltmarsh for foraging and nesting area for the light-footed clapper rail.

3. High saltmarsh for refugia for the rail.

4. Establishment of saltmarsh bird's-beak.

Performance Standards:
The project is deemed successful on showing that:

1. Channels and emergent wetland provide suitable, functional habitats for the California least tern and light-footed clapper rail.

2. Emergent wetlands are vegetated by patches of saltmarsh bird's-beak and 75 percent of the native species currently occurring in the Sweetwater River wetlands complex.

3. The channels shall be considered to provide habitat for the tern and rail on a showing that the channels provide suitable habitat for fish and invertebrate populations that are forage items for the California least tern and the light-footed clapper rail and these forage species are present. These forage species shall be considered present when the created or modified wetlands provide, for two years, 75 percent of the density and diversity of prey base as compared to an existing wetland in the Sweetwater River wetlands complex that does provide habitat for the tern and/or rail.

4. The emergent wetlands shall be considered to provide adequate habitat for the light-footed clapper rail when seven home ranges (i.e., non-overlapping areas two to four acres in size) composed of low, middle and high saltmarsh for two years are established.

5. The low marsh shall comprise at least 15 percent of this [emergent wetland] mix, and have at least 50 percent cover of cordgrass. The lower marsh in each [light-footed clapper rail] home range shall also have at least one patch of the cordgrass with a stem length of 60–80 centimeters, providing 90–100 percent cover that is 90–100 square meters in size and shown to be resilient (i.e., having the ability to maintain itself). A stand shall be considered to be resilient when it is exhibiting nitrogen fixation.

6. The middle saltmarsh shall provide at least 70 percent cover, and contain 75 percent of the native species typically found in this zone, in a comparable area in the Sweetwater River wetlands complex.

7. An attempt should be made to include high saltmarsh berms within, or immediately adjacent to, areas of low saltmarsh. The standard for the high saltmarsh is given below.

8. For saltmarsh bird's-beak and the light-footed clapper rail, the emergent wetlands shall be considered successful when the wetland creation and modification projects contain at least 15 percent high saltmarsh, with less than 10 percent cover from weedy species, and contain patches of saltmarsh bird's-beak for two years.

9. Saltmarsh bird's-beak shall be considered to be present when there are at least five separate patches of saltmarsh bird's-beak, each measuring one square meter in size, containing at least 20 individual plants, and separated from each other by at least 10 meters that are shown to be self-sustaining (i.e., stable or increasing in number and area) for three years.

10.3.3. Mitigation Attributes

The overall project involved numerous activities that had either positive or negative effects on the Sweetwater Marsh complex. "The CCC found that the mitigation and restoration elements of the proposed project would be of such benefit to the marsh complex that the overall project was [considered] wetland restoration, a permitted used under Section 30233, and therefore consistent with the Coastal Act" (CDP 6-83-319). Alternatively, the FWS's 1988 biological opinion found that the combined flood control and highway construction project would likely jeopardize species protected under the Endangered Species Act. As a result, a number of "reasonable and prudent alternatives" were devised to "insure that the project is not likely to jeopardize the continued existence of any endangered species or threatened species" (FWS, 1988).

On a more basic level, the development activities involved two components (i.e., highway construction and creation of a flood control channel) that were determined to result in the permanent loss of 15.6 acres of wetland habitat (FWS, 1988). Additionally, the 1988 biological opinion identified adverse impacts to the light-footed clapper rail and the California least tern due to the temporary fill for the highway detour and overall construction activities. Several beneficial activities, including wetland restoration, enhancement, acquisition, and preservation, were undertaken as compensatory mitigation for this loss of wetland habitat and associated adverse impacts. The resulting mitigation included both in-kind and out-of-kind elements.

Determining the mitigation ratio is complex, due to the multiple types of activities undertaken over the course of this project. Dredging and levee construction required for the flood control channel resulted in the loss of intertidal mudflat habitat, which was compensated for by the gain in tidally influenced openwater habitat in the expanded river channel. This is out-of-kind mitigation, and the resulting mitigation ratio was approximately 1:1 (i.e., six acres of channel habitat created, for 5.9 acres of mudflat habitat lost through dredging). The highway construction resulted in the filling of 9.6 acres of marsh habitat, which was mitigated through the restoration of 9.6 acres of connector marsh. This was in-kind mitigation, and the resulting mitigation ratio was 1:1. Impacts from the temporary fill of marsh habitat for the highway detour were addressed through the subsequent removal of the fill and restoration of the marsh area, a 1:1 mitigation ratio.

Two additional activities were completed to provide further compensatory mitigation for the construction related impacts: 1) creation of 17.1 acres of wetland at the eastern end of the "D" Street fill; and 2) modification of 25 acres of high saltmarsh into low, middle, and high marsh. Under the operational definitions for compensatory wetland mitigation activities described in this document, providing 17.1 acres of wetland at the eastern end of the "D" Street fill is considered restoration, because historic wetland habitat was re-established through the removal of fill material. Similarly, the modification of 25 acres of high saltmarsh is considered enhancement, because the activities were designed to improve the habitat mix and functions of existing marsh habitat. It is important to remember that the pre-existing high saltmarsh did provide some wetland functions prior to modification even though it was highly disturbed and occurred partially on fill. Moreover, subsequent investigations show that the wetland habitat provided through these restoration activities is not functionally equivalent to the wetland habitat lost to development (Zedler, pers. comm.).

Finally, the compensatory mitigation activities included acquisition and preservation of existing wetland habitat (188 acres) and habitat suitable for California least tern nesting (10.6 acres). These areas were subsequently designated a Fish and Wildlife Refuge.

10.3.4. Monitoring Program

The FWS's 1988 biological opinion outlines the required monitoring, specifically stating that "monitoring shall include comparative studies between created wetlands and existing wetlands in the Sweetwater River Wetlands Complex. Monitoring must include, at a minimum, salinity measurements, surveys of marsh topography and channel morphology, invertebrates and fish populations, and percent cover of wetland vegetation by species, and nitrogen fixation, and hydrology studies."

The Pacific Estuarine Research Laboratory, PERL, is conducting the monitoring which began in 1989. The following attributes are monitored on an annual basis by PERL: fish, invertebrates, soil salinity, plant species composition at low, medium and high marsh intertidal elevations, relative vigor and distribution of cordgrass (Spartina foliosa), and water quality including: water temperature, water salinity, dissolved oxygen, total carbon, total Kjeldahl nitrogen, ammonia, nitrate, nitrite, and total phosphorus. The water quality information is used to understand the causes for similarities and differences between the biota in the natural and constructed channels.

Adaptive management guides the monitoring program. As improved sampling methods are developed, they are incorporated into the program. As accumulated information is deemed adequate, sampling is decreased or terminated. To reduce damage and disturbance to sensitive species, PERL continually looks for the least intrusive sampling protocols that still provide the necessary information. In an effort to reduce costs, the monitoring of vegetative cover was not scheduled until sufficient habitat had developed. PERL has also completed several applied research projects aimed at developing new information relevant to continued management of the Sweetwater Marsh complex. These research projects have been funded through outside sources thereby further helping to contain the monitoring costs.

The combination of a long-term research program and compliance monitoring has improved the quality of the data and an understanding of the processes important to achieving successful wetland mitigation (for example see Boyer, et al., in press; Gibson, et al., 1994; Langis, et al., 1991; PERL, 1990; PERL, 1994; and Zedler, 1991, 1993). This process has demonstrated the importance of collecting data from the reference sites, allowing the evaluation of performance to account for interannual variability (PERL, 1990).

10.3.5. Evaluation of Performance

This mitigation project has many merits. Most notable, the project provides a well-established mechanism for determining if the required habitat quality is being achieved (i.e., utilizing the monitoring data to evaluate performance), a mechanism for identifying limiting factors (i.e., the PERL research program), and a mechanism for taking corrective action (i.e., the adaptive management process). For some attributes, the mitigation wetlands have met or exceeded the performance standards established in the biological opinion (FWS, 1988). According to the 1994 monitoring report (PERL, 1994), the following performance standards have been met:

75 percent of the native fish species and 75 percent of the native fish densities found in the reference channels. This performance standard has been met for four consecutive years (1990–1993). Sampling data collected in 1993 indicate the constructed channels contained slightly more fish than the natural channels, although the fish communities varied between the natural and constructed channels. The dominant species found in the constructed channels are among the preferred foods of the least tern.

75 percent of the native species of benthic invertebrates and 75 percent of the densities found in the reference channels. This performance standard has been met for two consecutive years (1992–1993). More recent sampling revealed a greater number of species in the constructed channel than in the natural channels. Crab availability as a prey source for light-footed clapper rail was studied in 1994. The data show that the number of crabs in the natural marsh was not greater than the number occurring in the constructed marsh.

The following performance standards have not been met at the writing of this case study:

Adequate habitat for the light-footed clapper rail. Adequate rail habitat is considered to occur when seven home ranges (i.e., non-overlapping areas of two to four acres) composed of low, middle and high saltmarsh have been established for two years. The 1994 monitoring report indicates that monitoring to assess the saltmarsh vegetation in relation to low, middle and high saltmarsh habitats will begin in 1995.

Presence and cover of cordgrass. The low marsh habitat shall have at least a 50 percent cover of cordgrass. One cordgrass patch in each clapper rail home range shall have stem heights of 60–80 centimeters, which provide 90–100 percent cover. This patch shall be 90–100 square meters in size, and must be resilient (i.e., demonstrate that the patch can maintained itself, and is exhibiting nitrogen fixation). Previous data show the cordgrass can achieve high densities in the mitigation area, but the mean stem height is shorter on average, and therefore considered unsuitable for light-footed clapper rails. More recently, this performance standard was modified through the adaptive management process, so that either the original density and height criteria can be met or those of Zedler (1993) can be met. The performance standard developed by Zedler (1993) is as follows: suitable habitat should be a density of at least 100 stems per square meter with at least 90 stems per square meter greater than 60 centimeters, of which at least 30 stems per square meter are greater than 90 cm in height. Data will be collected to permit an evaluation of performance using either performance standard.

High marsh habitat. The mitigation area shall contain at least 15 percent high saltmarsh vegetation. These areas of high saltmarsh shall have less than 10 percent weedy species. The high saltmarsh areas shall contain patches of saltmarsh bird's-beak for two years. Plant species in the high marsh habitat are similar in the mitigation and natural marshes, but the cover is lower in the mitigation marsh. Additionally, bare areas exist on the high part of the constructed islands. The reduced plant cover in the mitigation marsh is related to substrate deficiencies, which are discussed in Langis et al. (1991), Gibson et al., (1994), and Boyer et al. (in press).

Saltmarsh bird's-beak. This plant shall be considered established when there are at least five separate patches of saltmarsh bird's-beak, each measuring one square meter in size, containing at least 20 individual plants, and separated from each other by at least ten meters. The patches must be self-sustaining (i.e., stable or increasing in number and area) for three years. This performance standard is likely to be met in 1995 for plants seeded in a natural part of the Sweetwater Marsh (Zedler, pers. comm.). Three small patches are present in the mitigation area, and further seeding is planned for late 1995 (Zedler, pers. comm.). Through the adaptive management process, PERL has recently received approval for their recommendation to plant saltmarsh bird's-beak in the 17.1-acre restored marsh (Zedler, pers. comm.).

10.3.6. Applying the general procedures for evaluating wetland mitigation project performance

The FWS's 1988 biological opinion provides specific performance standards and clear guidelines for monitoring and evaluating wetland performance. However, establishing these procedures in a biological opinion completed after the coastal development permit was issued is not the preferred process. The standards and procedures for project evaluation should be made on the basis of information contained in a comprehensive mitigation plan required as a condition of permit approval. The following discussion illustrates how appropriate conditions and performance standards could have been incorporated into the permit and mitigation plan.

The initial coastal development permit, which only allowed for completion of the first phase of construction, stated that the project would not be consistent with the Coastal Act without assurances that the adverse impacts would be addressed at a later date. To address this concern, the first condition of the permit could have stipulated that all beneficial activities should precede the highway and flood control channel construction, or at a minimum occur concurrently. As it turned out, the beneficial activities did not commence until phase two of the highway construction. The temporary fill for the highway detour was addressed in the permit conditions, although the conditions only required removal of the fill and restoration of the area within six years. Mitigating for the temporal loss of habitat could have been addressed in the permit by requiring a mitigation ratio greater than one to one.

The coastal development permit should have contained specific conditions relating to the mitigation plan. Ideally, the mitigation plan should be submitted and approved prior to permit issuance. The permit conditions could provide clear guidance on the contents of the plan, as outlined in this procedural guidance document. For instance, the permit could state that the mitigation plan must include clear goals and objectives, and specific, quantifiable performance standards for evaluating project performance. The plan should clearly articulate how this project will improve habitat quality and address concerns regarding any species potentially suffering adverse impacts. The plan should also describe the monitoring program including a clear description of how the monitoring data will be used to document project performance. A description of potential remediation measures should also be included. For example, in this project an unexpected outbreak of a scale insect has had a negative impact on cordgrass vigor and survival. Applied research was subsequently completed to understand the mechanisms for insect establishment and control. This information has been useful for defining potential remediation options.

The performance standards described in the biological opinion (FWS, 1988) do contain some limitations. For instance, several performance standards relate to the establishment of habitat for the light-footed clapper rail. However, such performance standards do not provide direct requirements that the mitigation project actually result in the presence of clapper rails. In fact, related research shows that suitable clapper rail habitat must contain tall cordgrass rather than some specified average height, as illustrated by detailed comparisons between plant canopies in natural marshes used by clapper rails and the canopies in the mitigation area, which do not support clapper rail nesting (Zedler, 1993). The adaptive management process provides a mechanism for correcting these shortcomings. Currently, PERL is working to shift the performance standard from average height to height distribution standards described in Zedler (1993). In addition, the performance standards for the light-footed clapper rail and California least tern do not address all of the attributes important to the existence of these birds. Although the prey base (i.e., fish) for least tern is addressed, there may be other limiting factors apart from food availability, such as noise, size of habitat, human disturbance, and trash and debris that limit bird presence and habitat use.

Clearly, continued study of the mitigation area is required before a final determination of performance can be made. Yet this project provides a good illustration of the extreme level of effort, resources, and commitment required to achieve successful wetland mitigation. The long-term management and monitoring of this project will provide valuable data and information that can readily be applied to other mitigation projects in southern California.

checklist of information included in the permit file and the biological opinion

CHECKLIST OF INFORMATION INCLUDED IN THE PERMIT FILE AND THE MITIGATION PLAN FOR THE SWEETWATER MARSH MITIGATION PROJECT

SWEETWATER MARSH PERMIT FILE REVIEW

Mitigation Attributes:

SWEETWATER MARSH MITIGATION SITE EVALUATION

Project Information:

Habitat Characterization:

ENDNOTES

¹⁵Suggested goals, objectives, and performance standards are in italics.

¹⁶Information on the Fish and Wildlife Service's biological opinions is from: FWS, 1988.

¹⁷As used in the CCC coastal development permit, restoration is a general descriptor for any activity considered beneficial to the wetland. In fact, the overall project included numerous activities (e.g., enhancement, restoration, and creation) considered beneficial to the wetland. For the purposes of this case study, these beneficial activities are generally referred to as wetland mitigation.

¹⁸Although biological opinion 1-1-78-F-14-R2 (1988) did not specifically categorize this information as goals, objectives, and performance standards, the information was organized in this manner. All of the relevant information is taken from Feature 3 of the Reasonable and Prudent Alternatives in the 1988 biological opinion.

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