A Review of Compensatory Mitigation in Estuarine and Marine Habitats ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Acknowledgements Principle authors of this report were Emily French and Brian Topping (EPA Headquarters). Thank you to the reviewers, including Steve Martin from USACE Institute for Water Resources (retired); Susan Marie-Stedman from NOAA Headquarters; David O'Brien from NOAA Fisheries; Jennifer Siu from EPA Region 9; Palmer Hough, Betsy Valente and Brittany Bennett from EPA Headquarters; Aisling O'Shea from Massachusetts Department of Fish and Game ILF Program; and Kristina Tong from USACE Seattle District. They offered their expertise, including input on multiple drafts, and immeasurably improved this report. Thank you also to the staff at the USACE's Seattle, San Francisco, Los Angeles, Galveston, Jacksonville, Norfolk, and New England district offices for providing us with records on permittee-responsible mitigation and assisting with interpreting ORM records. Finally, we acknowledge the third-party mitigation providers who explained the landscape and habitats at their sites and shared their monitoring methods and performance standards. Thank you for the time that you took to exchange many phone calls and emails with us. We appreciate the assistance from all the aforementioned groups in writing this report and are thankful for their commitment to improving estuarine and marine compensatory mitigation. Cover photo from Gulf Islands National Seashore (National Park Service) in Florida, an area where the four habitats primarily featured in this report coexist. Photo by Emily French. 1 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 '>i1 ¦'.•inn . This review of compensatory mitigation in estuarine and marine habitats was conducted in support of the Clean Water Act 404(b)(1) Guidelines including the 2008 Final Rule Compensatory Mitigation for Losses of Aquatic Resources. It has been subjected to review by EPA and approved for release. The mention of trade names or commercial products does not constitute endorsement or recommendation for use. This review is not intended, nor can it be relied upon, to create any rights enforceable by any party in litigation with the United States. Anyone may decide to use the information provided in this document or not. This document is not a regulation itself, nor does it change or substitute for statutory provisions within EPA or USACE regulations. Thus, it does not impose legally binding requirements on EPA, USACE, States, or the regulated community. 2 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Contents Acknowledgements 1 Disclaimer 2 Glossary 5 Executive Summary 7 Introduction 8 Objectives 9 The focal habitats 10 Value and status of the focal habitats 12 Methods 14 Third-party mitigation 14 Permittee-responsible mitigation 15 Voluntary restoration and ambient monitoring 16 Results: Inventory 17 Third-party mitigation 17 Permittee-responsible mitigation 18 Voluntary restoration and ambient monitoring 19 Results: Seagrass 21 Third-party mitigation 21 Permittee-responsible mitigation 21 Monitoring and performance 22 Voluntary restoration and ambient monitoring 23 Results: Oysters 24 Third-party mitigation 24 Permittee-responsible mitigation 24 Monitoring and performance 25 Voluntary restoration and ambient monitoring 25 Results: Tidal flats 27 Third-party mitigation 27 Permittee-responsible mitigation 27 Monitoring and performance 27 3 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Voluntary restoration and ambient monitoring 28 Results: Shallow water 30 Third-party mitigation projects 30 Permittee-responsible mitigation projects 30 Monitoring and performance 31 Voluntary restoration and ambient monitoring 32 Discussion 33 Recommendations 38 Improving mitigation practices 38 Improving documentation and record-keeping 38 Next steps for research 39 Training opportunities 40 References 41 Appendix A- Data and tables 46 Table 1- Search Terms for third-party Mitigation in RIBITS 46 Table 2- Third-Party Mitigation Providers: Banks 47 Table 3- Third-Party Mitigation Providers: ILFs and Sites 49 Table 4- Department of the Army Permits 52 Table 5- Ambient monitoring programs 54 Table 6- California Eelgrass Mitigation Policy Performance Standards 55 Appendix B- Out-of-kind mitigation 56 Table 1- In-kind and out-of-kind mitigation 58 4 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Glossary 404 Program: A program established by Section 404 of the Clean Water Act regulating the discharge of dredge and fill material into waters of the U.S. that is implemented primarily by U.S. Army Corps of Engineers (USACE) or authorized states1 and the Environmental Protection Agency (EPA). Ambient monitoring site: A monitoring site that is not necessarily tied to a restoration project; it may be a naturally-occuring population of organisms or a natural habitat area monitored for preservation or research purposes. Assessment methodology: The mechanism or tool used to evaluate either the loss of functions or services at a permitted impact site or a gain in functions or services provided at an associated compensation site. Compensatory mitigation: Within the 404 Program, this refers to the restoration, establishment (creation), enhancement, or preservation of wetlands, streams, or other aquatic resources for the purpose of offsetting unavoidable adverse impacts. Credits: A unit of measure representing the accrual or attainment of aquatic functions or services at a compensatory mitigation site. DARTER (Data on Aquatic Resources Tracking for Effective Regulation): EPA database that receives data from the USACE ORM (OMBIL Regulatory Module) database. District: Refers to a USACE district office. ILF (In Lieu Fee): A sponsor that collects funds from multiple permittees in order to pool the financial resources necessary to build and maintain the compensatory mitigation site(s). The sponsor is a public agency or non-profit organization. ILF site: A compensatory mitigation project developed by an ILF to offset permitted losses of aquatic resource functions and services. Impact: In this report, impact refers to the adverse effects of a discharge of dredge or fill material into an aquatic resource. In-kind: Compensatory mitigation that provides a resource of a similar structural and functional type to the impacted resource. Instrument: Refers to a mitigation bank or ILF's binding legal agreement and any associated exhibits/attachments. 1 As of November 2022 Michigan, New Jersey and Florida has been authorized to implement the 404 permitting program for certain waters. 5 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 IRT (Interagency Review Team): A group of federal, tribal, state, and/or local regulatory and resource agency representatives that reviews documentation for and advises the group chairs (USACE district and any other agency chairing the IRT) regarding establishment and management of a mitigation bank or an ILF program or site. Focal habitats: Seagrass, oysters, tidal flats, and shallow water. Mitigation bank: A compensatory mitigation site with credits for sale that correspond to habitat area. Mitigation banks collect funds from permittees that have impacted habitat at another location. Mitigation bank sponsors are typically private organizations. Also referred to as "bank" throughout report. ORM (OBMIL Regulatory Module): An USAGE database that stores permit information, including 404 Program permit information. Out-of-kind: Compensatory mitigation that provides a resource of a different structural and functional type than the impacted resource. Oysters: Bivalve mollusks found in estuarine and marine, intertidal, and subtidal areas. PRM (Permittee-responsible mitigation): Compensatory mitigation performed by the permit applicant or their contractor. Provider: Any entity providing compensatory mitigation or restoration services. RIBITS (Regulatory In-Lieu Fee and Bank Information Tracking System): A national web-based application used by multiple federal agencies to track mitigation bank and ILF credits and details. Seagrass: Rooted, vascular, salt-tolerant plants that exist in subtidal and intertidal areas. Shallow water: Subtidal, vegetated or unvegetated estuarine or marine waters (see introduction section for more information). Sponsor: The entity that establishes and operates a bank or ILF program (i.e., mitigation bank or ILF program sponsor). Third-party mitigation: Compensatory mitigation performed by a mitigation bank or ILF program. Tidal flats: Intertidal, unvegetated, low-energy areas comprised of fine-grained material. Waters of the U.S.: Aquatic resources regulated under the Clean Water Act. 6 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Executive Summary Environmental restoration, the ecological improvement of natural resources, can be voluntary or can be required by regulation. Section 404 of the Clean Water Act (CWA) is an example of a regulation that requires environmental restoration (or compensatory mitigation when used in this context) to be performed when certain unavoidable environmental impacts occur. The CWA Section 404 Program regulates the discharge of dredged or fill material into waters of the United States, including in coastal habitats. Despite the efforts of voluntary and regulated restoration, coastal habitats continue to diminish in area and ecosystem functioning. To help assess the state of these efforts and to better inform mitigation decisions, this report reviews compensatory mitigation that has taken place under the CWA Section 404 Program in estuarine and marine habitats. Broadly, the report quantifies estuarine and marine third-party mitigation providers, then narrows the focus to seagrass, oyster, tidal flat, and shallow water habitats to provide examples of project types, monitoring methods, and performance standards. A review of large-scale voluntary restoration projects involving seagrass, oyster, tidal flat, and shallow water habitats is also included. This report documents practices from across the country, which may be useful for federal and state regulators who review permittee-responsible and third-party mitigation project proposals, and for mitigation and other restoration providers. Based on available information from the CWA Section 404 Program databases, permits, and mitigation bank and ILF (In-Lieu Fee) program documentation, estuarine and marine mitigation projects were found to comprise a small but significant proportion of all compensatory mitigation projects: 2% of banks, 21% of ILF programs, 9% of ILF program sites, and 5% of PRM (permittee-responsible mitigation). Compared to tidal flat and shallow water projects, seagrass and oyster mitigation projects were found to have more comprehensive monitoring methods and performance standards, and project area (size) may be more commonly measured and tracked. Seagrass mitigation may also be occuring in-kind more often than oyster, tidal flat, and shallow water mitigation. Preservation projects reviewed generally had fewer monitoring methods or performance standards than restoration, establishment, or enhancement projects. From this baseline review of existing practices for estuarine and marine compensatory mitigation, recommendations are made for future research and for CWA Section 404 program effectiveness. The challenges of providing compensation for impacts to, or in the form of, unstructured habitats (i.e., tidal flats) are discussed, alongside recommendations for record-keeping and development of assessment protocols. 7 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Introduction Wetlands, streams, and other aquatic resources in the U.S. are intrinsically valuable and essential to public health and well-being. However, humans are constantly modifying water bodies, including those in coastal areas where high population densities occur. Although statutes and regulations exist to protect aquatic resources, they also authorize impacts, which lead to direct, indirect, and cumulative effects. In 1989, President George H. W. Bush established the national "no net loss of wetlands" policy, which set the groundwork for agencies across the federal government to begin balancing wetland loss with reclamation and restoration efforts so the total acreage of wetlands across the U.S. would not decrease. However, "no net loss" is a goal, and does not mean no losses occur; wetlands and other aquatic resources are still lost through permit actions and unregulated activities. To offset impacts, regulatory programs can require mitigation for impacts, and voluntary programs also protect and restore wetlands, helping to pursue the goal of no net loss of wetlands overall.2 The Clean Water Act Section 404 program (hereafter, 404 Program) uses compensatory mitigation to not only protect against wetland loss, but also loss of other aquatic resources, including streams and coastal aquatic habitats. Compensatory mitigation is the offsetting of unavoidable impacts to wetlands or other aquatic resources resulting from a 404- permitted activity with wetlands or aquatic resources that function similarly and are of comparable size and value. Broadly, the 404 Program regulates the discharge of dredged and fill material into waters of the United States3, unless the activity is exempt from Section 404 regulation (e.g., certain farming and forestry activities). When potential permittees propose activities that will cause impacts to aquatic resources, they must show that steps have been taken to avoid impacts, that the remaining potential impacts have been minimized, and that compensation will be provided for all remaining unavoidable impacts4. The U.S. Army Corps of Engineers5 (USACE) and Environmental Protection Agency (EPA) jointly administer the 404 Program, through which USACE issues tens of thousands of permits each year (Vanderbilt et al. 2015). The National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service (NMFS), Fish and Wildlife Service (FWS), and state and local agencies coordinate and consult alongside EPA and USACE on 404 Program project reviews. Project size, impact type, affected habitat, permit type, and permit conditions dictate whether compensatory mitigation will be required. Compensatory mitigation can be provided though a third party (a mitigation bank or In-Lieu-Fee [ILF] Program) or through a project initiated by the permittee (permittee-responsible mitigation or PRM), and usually falls into one of four 2 For more information about federal funding sources for wetlands protection and restoration see https://www.epa.gov/wetlands/federal-funding-wetlands. 3 For the definition of "waters of the United States," see: https://www.epa.gov/wotus. 4 For more information on the CWA Section 404 regulatory program, see: https: //www,epa.gov/cwa- 404/permit-program-under-cwa-section-404. 5 Michigan, New Jersey, and Florida have assumed the administration of the CWA Section 404 regulatory program for many of the waters in their respective states. For more information about state and tribal assumption of the Section 404 regulatory program, see: https://www.epa.gov/cwa404g. 8 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 categories: restoration, preservation, establishment (creation), or enhancement. The 2008 Mitigation Rule, which revised and expanded rules governing how compensatory mitigation projects are developed, reviewed, and implemented, requires performance standards to be established for compensatory mitigation sites and monitoring reports to be submitted to assess progress (33 CFR 332.4(c) and 40 CFR 230.94(c)). The 2008 Mitigation Rule also includes a provision for difficult-to-replace resources, encouraging in-kind compensation (33 CFR 332.3(e)(3)/40 CFR 230.93(e)(3)). Despite the efforts of both regulatory and voluntary programs, aquatic resources in coastal areas continue to diminish in area and ecosystem functioning. In back-to-back reports, FWS and NOAA found that coastal wetlands have suffered considerable losses during the past 20 years (Stedman and Dahl 2008, Dahl and Stedman 2013). Coastal areas are not only threatened by development but also by a suite of other stressors such as saltwater intrusion, sea level rise, non-native species, and water quality impairment. A continuation of such aquatic resource losses in coastal areas could result in an inability of coasts to buffer water quality, increased flooding and vulnerability to storm surges, and extensive habitat loss (Rezaie etal. 2020, Li etal. 2018). This report reviews compensatory mitigation that has taken place in estuarine and marine areas under the 404 Program. Although coastal wetlands and aquatic resources are diverse and include freshwater and saltwater habitats, this report focuses exclusively on saltwater habitats and specifically on seagrass, oysters, tidal flats, and shallow water (referred to as 'focal habitats' throughout), which are among the habitats referred to as "special aquatic sites" under the 404(b)(1) Guidelines (EPA 1980)6. In the past, 404 Program staff at EPA have noted that they had few examples to reference when compensation is needed for impacts to these habitats, potentially because there are fewer permits involving these habitats being issued (compared to freshwater wetlands and streams). To maximize examples of projects involving seagrass, oysters, tidal flats and shallow water, a review of voluntary restoration and ambient monitoring projects is also included in this report. Objectives The objectives of this report include the following: 1. To understand how much estuarine and marine compensatory mitigation is occuring across the U.S.; 2. To better inform mitigation decisions for seagrass, oysters, tidal flats, and shallow water habitats by (a) examining what types of compensatory mitigation projects exist and what monitoring and performance criteria are used to evaluate them, and (b) by providing references to voluntary restoration and ambient monitoring projects for the same habitats. 6 The 404(b)(1) Guidelines (EPA 1980), a regulation central to the 404 Program, acknowledges that some high-value habitats are especially difficult to replace and discourages the issuance of permits that would result in their degradation or loss. The regulation identifies "special aquatic sites" that include seagrass (40 CFR 230.43), mudflats (40 CFR 230.42), and sanctuaries or refuges (40 CFR 230.40), which are often created to protect oysters. 9 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Although there are other federal programs that require compensation for adverse impacts, such as Natural Resource Damage Assessment or USACE Civil Works, only 404 Program compensatory mitigation is evaluated in this report. This report provides information that may be useful to federal and state regulators who review permittee-responsible and third- party compensatory mitigation proposals, and to mitigation providers who develop and implement compensatory mitigation projects. The focal habitats Oysters, seagrass, and tidal flats are found along shorelines nationwide and are common features of estuaries and coastal bays. The three habitats co-occur in temperate areas of the contiguous U.S., in shallow or intertidal waters. Seagrasses are rooted vascular underwater or intertidal plants, distinguishing them from algae (e.g., kelp) which do not have roots. Seagrasses grow in contiguous 'beds' or patches. Seagrass beds or patches may fluctuate in size and location seasonally and from year to year. Ten native seagrass species are found in the continental U.S.: Zostera marina (commonly called eelgrass], Ruppia maritima, Halodule wrightii, Syringodium filiforme, Thalassia testudinum, Halophila engelmannii, Halophila decipiens, Halophila johnsonii, Phyllospadixscouleri, and Phyllospadix torreyi. One non-native seagrass species, Zostera japonica, is featured in this report. The term 'seagrass' rather than 'submerged aquatic vegetation' (SAV) is used here to identify salt-tolerant SAV species found in estuarine and marine settings. Oysters are bivalve mollusks found in areas with estuarine and marine salinities. They grow in subtidal waters and sometimes intertidal areas depending upon climate (exposure to extreme hot or cold air temperatures can desiccate or freeze oysters). There are two oyster species native to the continental U.S.: Crassostrea virginica (commonly called Atlantic oysters) found on the east and gulf coasts, and Ostrea lurida (commonly called Olympia oysters) found on the west coast. Both species have been heavily exploited commercially, with only a small percentage of their historic native populations remaining. Although both species formed three-dimensional reef structures historically, few natural reefs persist, and often, oysters are only found in patchy clumps. They are also found as two-dimensional restoration projects, on reef balls or oyster castles as part of restoration projects, or on shell bags or shell hash placed along living shorelines for restoration. For the purposes of this report, and because few classic three-dimensional oyster reefs still persist, all oyster presence was counted when searching for compensatory mitigation projects. One non-native oyster species, Crassostrea gigas (commonly called Asian oyster), is featured in this report. Tidal flats can be broad, low-energy sheltered flats with fine-grained material; narrow, fringing areas bordering salt marsh; or tidal creeks, which are unvegetated channels exposed at low tide. Tidal flats occur in intertidal, estuarine or marine, relatively low- energy areas. EPA regulations define mudflats as "broad, flat areas along the sea coast and in coastal rivers...exposed at extremely low tides and inundated at high tides... substrate containing organic material and particles smaller in size than sand... unvegetated or vegetated only with algal mats" (40 CFR 230.42). 10 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Because the definition of tidal flats may vary, projects are only included in this report if mitigation documentation or bank or ILF representatives self-identified as having tidal flat (mudflat/sand flat) presence. Tidal flat areas that mitigation providers expected to become vegetated in the future to produce tidal marsh are not included. Additionally, the term 'tidal flat' is used throughout this report, as opposed to 'mudflat', to be inclusive of sand flats, which are tidal flats located near high energy areas (e.g., oceans). However, sandy, high- energy beaches are not included in this report. Shallow water is defined in this report as subtidal (permanently covered by water) estuarine or marine area, vegetated or unvegetated, with or without biogenic (e.g., oyster) structures. 'Shallow' is a relative term; its definition changes depending on the region of the U.S. and who is defining it. For instance, an EPA shallow water research conference defined shallow water as "all marine and estuarine waters within four meters below mean low water (MLW), including the intertidal zone" (Reilly et al. 1999), while other publications have defined shallow water as between MLW and two meters deep (Bilkovic et al. 2009). After consideration of the variability in turbidity and in light penetration depth in estuarine and marine waters nationwide, three meters MLW was chosen as the cutoff depth for 'shallow water' for the purposes of this report. However, compensatory mitigation documentation obtained for this research rarely stated water depth at mitigation sites, making it difficult to say that every mitigation example featured in this report conforms to this depth range (zero to three meters MLW). Ultimately, the authors' best professional judgment was used, and the nature of mitigation projects included, for example creosote piling removal or preservation of an embayment, seemed unlikely to exhibit water depths greater than three meters. Data on seagrass, oysters, tidal flats, and shallow water habitats can be collected using aerial photography, sonar surveys, and in-situ diving and wading surveys. Common methods for monitoring seagrass and oyster populations involve measuring the density and size of plants or individuals. Tidal flat and shallow water monitoring may include water quality measurements, sediment toxicity, grain size, infauna, fish communities, and other wildlife presence. Box 1- Habitat types explored in this report Seagrass: Rooted, vascular, salt-tolerant plants that exist in subtidal and intertidal areas. Not to be confused with seaweed or macroalgae such as kelp. Oysters: Bivalve mollusks found in estuarine and marine, intertidal, and subtidal areas. Few natural three-dimensional structures remain due to overexploitation. Tidal flats: Intertidal, unvegetated, low-energy areas comprised of fine-grained material. Present in estuarine and marine areas, and can appear as wide flats, salt marsh fringe or intertidal channels. Shallow water: Subtidal, vegetated or unvegetated estuarine or marine waters with or without biogenic structures. 11 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Value and status of the focal habitats Seagrass, oysters, tidal flats, and shallow water provide important habitat for both commercially valuable species and small fish and invertebrates that are essential components of the coastal ocean food web. Oysters and seagrasses are ecosystem engineers, providing structure and refuge with their shells, canopies, and roots. Native and migrating shorebirds use tidal flats to feed, and tidal flat and shallow water areas harbor abundant infauna, including marine worms, clams, and crustaceans (Ray 2000). Tidal flats and shallow water interspersed among structured habitats (like mangroves, salt marsh, seagrass, or oysters) create a mosaic of foraging areas for predators (Orth et al. 1984, Whitlow and Grabowski 2012, Kellogg et al. 2013). All of the focal habitats improve water quality by functioning as coastal filters that trap and remove excess nutrients and suspended sediments before they are exported to the ocean (Mcglathery et al. 2007, Kellogg et al. 2018). Oysters and seagrasses assimilate nitrogen, phosphorus, and carbon into their tissue and shell, sequestering it temporarily or permanently depending upon the persistence of populations and whether the tissue and shell are buried, consumed, or exported (Newell et al. 2004, Fourqurean et al. 2012). Benthic microalgae, which occur at the sediment-water interface in intertidal and shallow subtidal areas, function as a cap to retain sediment and nutrients (Pedersen et al. 2004). Oysters and seagrasses create heterogeneity in sediments and aid in delivering organic matter to the surface, both of which facilitate denitrification (removal of nitrogen from the system) (Newell et al. 2005, Ward et al.1984, Aoki et al. 2019). There is no nationwide analysis for how much seagrass, oyster, tidal flat, or shallow water areas have decreased in acreage over time; however, some data and examples are available. In the Chesapeake Bay, the largest estuary in the U.S., the oyster population is currently less than 1% of historical levels (Wilberg etal. 2010). Eelgrass, one of two primary seagrass species in the Chesapeake Bay, was historically abundant but has declined in area by 64% over the last three decades (Richardson et al. 2018). In Maine, overfishing has significantly reduced the abundance and diversity of species associated with tidal flats (Brown and Wilson 1997). Along the Gulf of Mexico coast, several species of migratory shorebirds are declining due to loss of coastal wetlands, including tidal flats and sandy beaches (Withers 2002). Shallow water losses in the Gulf of Mexico are being offset as storms and sea level rise, causing the conversion of coastal marshes to shallow water habitat (Dahl 2011). Aside from habitat conversion, a ubiquitous accelerant to the degradation of these habitats is reduction of water quality, such as changes in water temperature, nutrients, and alkalinity. Seagrasses and oysters are more vulnerable to mortality during sustained high water temperatures (Moore and Jarvis 2008, Lowe et al. 2017, Green et al. 2019), and the frequency of high-temperature events is predicted to rise. Excess nutrients from water pollution may cause epiphytic algal growth on seagrass, which can prevent photosynthesis (Dennison et al. 1993, Short and Burdick 1995). Oysters are threatened by rapidly increasing acidity and CO2 levels in estuaries, which can decrease shell growth, size, and strength (Hettinger et al. 2012, Waldbusser et al. 2011), leading to a reduction in the number of juvenile oysters that survive into adulthood. Water quality impairment also has negative effects on shallow water and tidal flats; the deposition of excess suspended solids 12 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 can have cascading detrimental effects on tidal flat benthic communities (Reimer et al. 2015), and water contamination can cause fish kills and harm to shorebirds (Hargreaves et al. 2011). EPA's National Estuary Program (NEP), a network of 28 sites, and NOAA's National Estuarine Research Reserve System (NERRS), a network of 29 sites, are among the restoration and preservation programs around the country helping to conserve oysters, seagrass, tidal flats, and shallow water habitat. These two programs preserve over one million acres of estuaries. The National Park Service (NPS) also preserves thousands of acres of estuaries. Examples of large-scale restoration include Chesapeake Bay's "10 Tributaries by 2025" program, which began restoring oysters in 10 rivers in 2013, and the "Seagrass Restoration in Virginia's Coastal Bays" project, which began in 1999. These efforts have respectively been called the largest oyster and seagrass restoration projects in the nation. Tampa Bay is an example of a successful water quality improvement project. It is a shallow bay with an average depth of 12 ft and includes oyster, tidal flat, and seagrass habitat. Point source runoff reduction was part of a nutrient management strategy implemented in the 1980s, and subsequently, the Bay has experienced a 60% reduction in total nitrogen load and marked water quality improvements in shallow water habitat (Greening et al. 2011). 13 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Methods This report reviews compensatory mitigation implemented by third parties (mitigation banks and ILF programs) and permittees, in addition to voluntary restoration and ambient monitoring sites. The information is organized into subsections: third-party mitigation, permittee-responsible mitigation, and voluntary restoration and ambient monitoring. The results sections for each resource type also include a monitoring and performance subsection in which third-party and PRM are discussed. The aim of this report is to represent the most up-to-date and comprehensive information available. However, some relevant information was inaccessible (e.g., monitoring reports). To avoid potentially incomplete or misleading comparisons among specific projects, names of third-party providers and Department of the Army permit numbers are not identified in the body of this report. Instead, they are listed in Appendix A (Tables 2 and 3). Third-party mitigation RIBITS search- The USACE database RIBITS (Regulatory In-Lieu Fee and Bank Information Tracking System)7 was queried for banks, ILF programs, and ILF sites where the focal habitats were present. The search was conducted in March 2019 and was updated in February 2021. The database was searched for third-party compensation in several ways. First, the "Bank Summary Interactive" report was searched by the "Cowardin system list" field for estuarine and marine sites (specifically, the search was performed using the following string of terms: marine|estuarine|tidal|subtidal|intertidal|El|E2|Ml|M2). Then, the "Bank Credit Classification Summary by Jurisdiction" report was searched, and the "Credit Classification Type" and "Credit Classification" fields were filtered by the same terms. Because some bank/ILF sites that were expected to appear in the search results but did not, the reports for 23 keywords related to the focal habitats were also searched (Appendix A Table 1). A few bank/ILF sites were also found by panning within the RIBITS map viewer. Finally, through discussions with bank and ILF representatives, several ILF sites were discovered that were not on RIBITS. If the ILF program was on RIBITS already, these programs' sites were included. These search methods returned banks and ILFs that are selling, have sold, or are approved to sell estuarine and marine credits (statuses in RIBITS included "sold out," "approved," and "terminated"). Pending banks were not included because their status could change before approval or could never be approved, and no umbrella banks appeared in the search results. Several pending ILF sites were included because their programs were approved, their sites secured, and their plans were available for Interagency Review Team (IRT) review. Documentation requests and analysis- At present, identifying third-party providers that have seagrass, oyster, tidal flat, or shallow water habitat presence from RIBITS data is not straightforward because credit types are named broadly (for example, "wetland" or variants of Cowardin classes, like "El"). Other fields within RIBITS records also do not 7 https://ribits.ops.usace.army.mil/. 14 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 typically have specific habitat information. Therefore, studying instruments, mitigation plans, and monitoring reports from the RIBITS cyber repository was necessary. These materials were downloaded and reviewed for presence of the focal habitats, and for compensatory mitigation project types, performance standards, and monitoring methods. If none of the focal habitats were mentioned in this documentation, the bank or ILF representative designated on RIBITS was contacted and asked if they knew of the presence of these habitats on their sites. The bank/ILF was not included in the results section of this report if the bank or ILF representative was unsure whether the habitats were present at their sites. Permittee-responsible mitigation DARTER search- EPA's DARTER (Data on Aquatic Resources Tracking for Effective Regulation) database was queried to find examples of compensatory mitigation projects that involved the focal habitats in April 2019. DARTER houses information about USACE decisions and milestones in the permitting process from the USACE ORM (OMBIL Regulatory Module)8 database. Permit actions were downloaded from DARTER and retained if any one of 22 mitigation- related fields were filled out. The remaining projects were filtered by three fields: mitigation type, regulation project was authorized under (e.g., Clean Water Act, Rivers and Harbors Act, or blank) and Cowardin (Cowardin 1979) classification. Unlike RIBITS, which has only third-party mitigation projects, DARTER has projects with compensation provided by all three mitigation mechanisms (permittee-responsible, mitigation bank, or ILF). Therefore, to avoid duplication from the third-party mitigation RIBITS search, only projects with "permittee-responsible mitigation'" under the mitigation type field were retained. Next, only projects authorized under CWA Section 404 were retained. Finally, projects were filtered by Cowardin classification to retain only estuarine and marine projects. A small number of projects were eliminated based on manual screening of the state field, for example, for projects that occurred within inland states, the information in the Cowardin classification field was assumed to be a typo. The resulting records were used to determine states with the highest frequency of permits potentially requiring compensatory mitigation in the focal habitats. Permit requests and analysis- The five states with the most estuarine and marine compensatory mitigation projects according to the search process were selected.9 Project managers (hereafter, PMs) from each of the six corresponding USACE districts (hereafter, districts) were established as points of contact and were emailed a request for permits, mitigation plans, and any available monitoring reports for the projects. The documentation received was reviewed to investigate whether it involved one of the focal habitats. If it did, impacts and compensation details were noted. Only projects that could be verified as having been permitted were included in this report. Note, some projects are permitted but never built, and if the permitted impacts do not 8 httpsi//permits,ops,usace,army,mil/orm-public#. 9 Anticipating a large volume of permits, the PRM aspect of the study was limited to five states due to time and resource constraints. 15 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 occur, the compensatory mitigation does not occur either. Although mitigation information was taken from the most recent information available for each project, in some cases only the permit was available, which made it difficult to determine whether the mitigation project occurred. In the results sections, the actions detailed in permits are referred to in the past tense, unless documentation received indicated they are still in progress. Finally, most project documentation referred directly to "compensatory mitigation," although some referred to "mitigation." It was assumed that "mitigation" was used to mean "compensatory mitigation," and all references in this report to "mitigation" are to compensatory mitigation. Voluntary restoration and ambient monitoring A review of voluntary restoration and ambient monitoring projects assisted with understanding which monitoring methods and performance standards were typical for seagrass, oysters, tidal flats, and shallow water. Ambient monitoring is monitoring that is not necessarily connected to a restoration project, and such monitoring can occur on natural populations of organisms or habitat areas. Voluntary restoration is restoration that was not required by a regulatory program. Ambient monitoring and voluntary restoration programs can help inform monitoring methods and performance standards developed for compensatory mitigation projects. To find examples of these types of projects, an internet search was performed, and the documentation retrieved was reviewed for project type and monitoring and assessment information. In many cases, especially for national programs, follow up and clarification with a program representative was necessary to ask for more documentation and verify the methodology was current. The programs and projects (Appendix A, Table 5) are global, regional, and local but are mainly large-scale. 16 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Results: Inventory Third-party mitigation Sixty-one IRT-approved mitigation banks and ILFs from RIBITS were categorized as estuarine and/or marine. While vetting documentation, it became apparent that several of the banks and ILFs had only freshwater habitats and were likely miscategorized. Ultimately, 54 programs with estuarine or marine habitat were found in the search (38 banks and 16 ILF programs). The ILF programs include 111 sites (Figure la and b, Appendix A Tables 2 and 3). The number of estuarine or marine ILFs and banks constitutes 2% of banks, 21% of ILFs, and 9% of ILF sites on RIBITS. Forty-four banks and ILFs across 18 states included seagrass, oyster, tidal flat, and/or shallow water (subtidal) habitats Figure 1 - A: The number of banks with estuarine or marine habitats per state, B: The number of ILF sites with estuarine or marine habitat per state. 17 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 State Seagrass Oysters Tidal flat Shallow water Alaska 2 - 5 2 California 2 - 2 4 Connecticut - 1 - - Florida 4 2 1 6 Georgia - - - 1 Louisiana - - - 1 Maine 1 - 1 Massachusetts 1 1 - 1 Mississippi - - - 1 New Hampshire - 1 - 1 New Jersey - - 6 New York - - 1 1 North Carolina - 1 1 1 Oregon - - - 2 South Carolina - - 2 2 Texas - - 1 1 Virginia 1 2 2 2 Washington 1 1 2 - Totals 12 9 24 32 Table 1- Third-party mitigation providers (ILF programs and banks) with focal habitats present by state (some programs and banks have more than one focal habitat present]. A few unusual circumstances were revealed during the review process. Although four banks had tidal flat habitat, bank representatives explained that it was not the final desired habitat and that they were expected to vegetate, so they were not considered tidal flat for the purposes of this report. There were also two banks in Florida where seagrass and tidal flats were present within the bank boundaries, but sponsors were not issuing credits for those areas, so those habitats were not counted as being present. Additionally, several banks indicated uncertainty regarding oyster or seagrass presence as they did not conduct monitoring of the underwater portions of the project site. Finally, in the results sections for each resource type, area (in the form of acreage) is not given for third-party mitigation projects, though it is for PRM projects; third-party mitigation projects were often mosaics of habitats and did not provide area measurements for the focal habitats in their properties. Permittee-responsible mitigation The initial search for projects that required compensatory mitigation in DARTER resulted in 29,158 projects, which were then filtered and screened. Many records were not able to be used because they were not labeled as a CWA Section 404 project (21% of 29,158) or because they were not labeled as permittee-responsible (61%). There were 9051 remaining records, 487 of which had a Cowardin class of estuarine or marine (5%). The remaining records, which spanned 21 states, were sorted by state and the five states with 18 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 the most records were selected for data collection. The states with the most projects were Washington, Virginia, California, Florida, and Texas, with 260 projects total. The search was performed on records from mid-2007 (ORM records began to be loaded into DARTER starting in 2007) to April 2019. PMs at corresponding district offices sent documentation on 214 of the 260 projects, and studying the documents revealed that 55 of them involved the focal habitats (Table 2). PMs reported some difficulty in locating and accessing records for various reasons. For instance, some districts' records were digitized while others were not. The records provided for each permit rarely contained a copy of each of the three requested documents (permit, mitigation plan, and at least one monitoring report). PMs provided the following types of documents: Nationwide Permit Verification letters, Letters of Permission, Department of the Army Permits, Memorandum for the Record, mitigation compliance reports, monitoring reports, mitigation plans, IRT correspondence, and USACE internal correspondence. However, the project packets received rarely included more than a few of these document types. State USACE district # Projects PMs provided # Permitted projects where mitigation involved focus habitats Seagrass Oysters Tidal flat Shallow water California LA 15 2 - - 1 1 San Francisco 21 8 5 - 2 1 Virginia Norfolk 43 5 2 3 - - Texas Galveston 7 2 - 1 - 1 Washington Seattle 47 28 1 - 1 26 Florida Jacksonville 81 11 5 1 - 5 Totals 214 56 13 5 4 34 Table 2- The number of permittee-responsible projects with focal habitats present at their mitigation sites by state and USACE district [some projects have more than one focal habitat present]. Most mitigation project permits were issued post-2008 (Appendix A, Table 4), and most involved restoration, establishment, or enhancement rather than preservation. In the results section for each resource type, area is given (in the form of acreage) for permittee- responsible mitigation as permit documentation usually included it. Voluntary restoration and ambient monitoring Although the internet search was not exhaustive, 17 examples of worldwide, national, and regional restoration and ambient monitoring programs that monitor seagrass, oysters, tidal flats, or shallow water were found (Appendix A Table 5). There was no shortage of 19 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 academic studies with thorough monitoring and performance standards, but because those studies' goals were research-oriented and more complex than the average mitigation project, they were not included. 20 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Results: Seagrass Third-party mitigation There were 12 third-party mitigation providers (three banks, nine ILFs) with seagrass presence at their sites. The age of sites ranged widely, one bank began restoring seagrass areas in the 1990s while one bank and one 1LF have not yet implemented their seagrass restoration components (as of 2021). The seagrass at most sites was eelgrass, though several programs in the southeast worked with H. wrightii, S.filiforme and T, Lestudinum. Half of the providers were preserving existing populations of seagrass at their sites, the remainder of the providers were restoring, creating, or enhancing seagrass in a variety of ways. Several providers transplanted seagrass from donor beds to restoration sites and one provider distributed seeds to facilitate seagrass reestablishment. Three providers employed topographical restoration techniques (removing fill or bringing propeller scars and other trenches up to a suitable elevation for seagrass colonization), including one provider that used dredged material. After topographical restoration, seagrass was either transplanted or expected to recruit to the area naturally. One provider installed bird stakes, which are platforms for birds to land on that enhance sediment nutrients and facilitate colonization of seagrass populations (Fourqurean et al. 1995). Finally, one provider removed a tidal restriction, which allowed seagrass to colonize part of the bank area. Seagrass mitigation projects (third-party or PRM) reviewed in this section occurred in the states in shown in red. Mitigation project types consisted of transplantation from donor beds, topographical restoration, and seed distribution. Topographical restoration projects included excavating uplands, placing sediment tubes in boat propeller scars (Figure 2), and filling in a channel dredged though a historic seagrass flat. Multiple projects mentioned the use of dredged material to construct the mitigation area. Seed distribution projects involved a university laboratory collecting flowering shoots of seagrass, extracting mature seeds, and seeding designated areas as compensatory mitigation. Impact Permittee-responsible mitigation There were 13 PRM projects, all of which restored, created, or enhanced seagrass beds (there were no preservation projects) and were permitted or began somewhat recently, between 2010-2018. The majority of projects took place in Florida and California. While all of the seagrass mitigation projects in California, Washington, and Virginia involved eelgrass, Florida's projects involved H. wrightii, S.filiforme•, R. maritima, and T. lestudinum., as well as the non-native llalophila ovalis. Projects ranged in size from 0.005 to 2.61 acres, but most were small, less than one acre. Figure 2- Sediment tubes used for seagrass restoration in St Joseph Bay, Florida. Photo by Florida DEP. 21 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 types included public park projects in which boat ramps, jetties, trails, and culverts were installed. Impacts also included installing poles for power lines, roadway and shoreline improvement projects, dredging at a private residence, and a commercial dock installation. Monitoring and performance Most third-party and PRM seagrass projects were restoration, enhancement, or establishment projects that had an acreage goal. A few projects had 'areal expansion of seagrass beds' as a performance standard, although it was informal because there was no set time limit or area goal. Monitoring methods and performance standards for the restoration, enhancement, and establishment projects centered around canopy height, shoot density, and percent cover. Most projects required in-situ monitoring, while a few monitored seagrass beds via aerial surveys (these project types differed in that they used seeds rather than transplants for restoration). One project used side-scan sonar for monitoring its restored seagrass populations; although the sites were over ten years old, the provider was interested in obtaining additional credits. Some third-party providers had preservation sites, none of which had monitoring or performance standards for the seagrass present. Several projects simply required noting land-use changes or landscape alterations (on foot or by plane), and several required taking photos, some at established locations (photo points). The majority of restoration, enhancement, or establishment projects required reference seagrass areas to be assessed in conjunction with monitoring the mitigation areas. These projects usually required percent cover (and sometimes density and canopy height) at the mitigation site to be equivalent to the reference site at the end of a monitoring period. However, one project required percent cover to be equivalent to reference sites for two consecutive years only within the monitoring period. Another required 80% cover and density of reference site levels by the end of the monitoring period. Seagrass mitigation projects in California follow performance standards established in the California Eelgrass Mitigation Policy (or CEMP, NMFS 2014) or its predecessor, the Southern California Eelgrass Mitigation Policy. The CEMP establishes a preference for in- kind eelgrass compensatory mitigation, requires compensatory mitigation at a 1:1.2 ratio, and requires at least five years of in-situ monitoring. Although the CEMP does not include a suggested set of monitoring methods, it does have a suggested set of performance standards for area, percent cover and shoot density at zero and six months and at years one to five (Appendix A, Table 6). Projects with in-situ monitoring used quadrats and transects to measure percent cover. Several projects used the Braun-Blanquet method, which gives seagrass cover inside a quadrat a score between one and five (Bell et al. 2008), while several estimated percent cover using a grid within a quadrat (Rezek et al. 2019). Many projects used fixed transects, while a few others selected transects or monitoring areas randomly. Performance standards required that percent cover increase over time. Several projects included informal (not quantitative) observance and notation of seagrass epifauna (fish and invertebrates), epiphytes, macroalgae, and bioturbation. One project also measured the prevalence of eelgrass wasting disease, which is caused by a pathogen and periodically occurs in North American and European eelgrass populations 22 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 (Smithsonian 2018). A pending project proposes installing signage to increase seagrass bed visibility to boaters. The associated performance standard is a decrease in the number of boat scars over time. One project plans to measure sediment grain size within seagrass beds. In Florida, because seagrass species are so numerous, the number species present was also monitored in several projects. Voluntary restoration and ambient monitoring Mitigation projects retrieved in the search (Box 2) had similar monitoring methods to voluntary restoration and ambient site monitoring programs. One difference between the two was size: ambient and voluntary monitoring or restoration projects were typically larger than compensatory mitigation sites and as a result could use aerial surveys rather than in-situ monitoring. Ambient monitoring/restoration projects were also sometimes more technical, measuring attributes like epifauna that live in seagrass beds. Voluntary restoration and ambient monitoring projects did not typically assign performance standards. Finally, no voluntary restoration projects modified the seafloor level to a depth at which seagrass could grow; this was only seen in compensatory mitigation projects. There are many examples of worldwide, national, regional, and local seagrass restoration and monitoring programs. One program, Zostera Experimental Network, which was grant- funded for six years but has been terminated, monitored ambient populations of eelgrass at 15 sites worldwide. Another worldwide monitoring program is SeagrassNet, which at one time had 122 sites across 33 countries, although not all sites are currently operational. On a national scale, NOAA's NERRS and EPA's NEP monitor seagrass at the reserves and sites where it is present. For mapping resources, marinecadastre.gov hosts a national seagrass layer that is a composite of data from state websites (NOAA and BOEM, 2019). There are a few examples of regional seagrass monitoring programs. The Virginia Institute of Marine Science has annual aerial surveys at sites across the Chesapeake Bay (Virginia and Maryland). Some sites in this program have been monitored since the late 1980s. The Florida Department of Environmental Protection (FL DEP) has an Aquatic Preserve Program with 41 sites where seagrass is monitored where it is found. The Tampa Bay NEP has been conducting aerial surveys and monitoring transects since the mid-1990s. Finally, a large-scale eelgrass restoration project in Virginia's Coastal Bays monitors restored populations and is billed as the world's largest seagrass restoration project. Box 2- Common practices for monitoring seagrass mitigation sites Common monitoring metrics: Percent cover, shoot density, area, canopy height Other monitoring metrics: Wasting disease, water quality improvement, qualitative assessments of epifauna, nekton, macroalgae, or bioturbation Monitoring types: In-situ survey, aerial survey, sonar survey Performance standards: Typically involved yearly documentation of progress toward an acreage, percent cover and/or shoot density goal compared to reference site(s) 23 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Results: Oysters Third-party mitigation Nine third-party mitigation providers (one bank, eight ILFs) had oyster presence at their sites. Site ages ranged from early 2000s to not-yet-completed (as of 2021). The oyster species across all sites was C. Virginia (or eastern oyster), except for one ILF site which had C. gig as (Asian oyster). About half of the providers were restoring, creating, or enhancing oyster areas or reefs, while the other projects were preserving existing populations or had created shoreline structure onto which wild oysters had recruited (providers had not necessarily created the structures for this purpose). Techniques used by the five providers restoring creating, or enhancing oyster areas include deposition of oyster shell or other shell types (e.g., clam) for natural recruitment (when wild oyster larvae attach to hard structures) or seeding reefs with 'spat-on-shell' (juvenile oysters attached to shell, Figure 3). Permittee-responsible mitigation Five oyster PRM projects in Virginia, Texas, and Florida were permitted between 2005- 2019. All projects involved the eastern oyster. All projects were enhancement, establishment, or restoration projects as opposed to preservation. Two projects were small (<0.0.1 acre) while the other three ranged from 0.6 to 1.1 acres. Oyster mitigation projects (third-party or PRM) reviewed in this section occurred in the states in shown in red. projects (four of five) expected natural recruitment, while one project moved live existing oysters. No spat-on-shell (Figure 3) were used. Impact types were public (a city building a seawall, a utility company installing poles for power lines, and a military base building a training facility) as well as commercial (a dredged material transfer facility, bulkhead construction at a restaurant, and two commercial dock facilities). Project iypes included constructing oyster areas using oyster shell and other materials like crushed concrete, payments to a non-profit for the purchase of oyster shell for restoration purposes, constructing a shoreline structure to which oysters recruited, and moving existing oysters out of a project's impact footprint. The project that moved existing oysters built a 15-inch reef base outside of the impact area that oysters and associated material were transferred to. Most PRM Figure 3- 'Spat on shell', juvenile oysters attached to a recycled oyster shell in a hatchety setting. Photo by Emily French. 24 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Monitoring and performance Monitoring methods and performance standards for PRM and third-party projects were not available for every oyster mitigation project. A few third-party preservation sites with oyster presence did not do any oyster-focused monitoring. Several PRM projects either did not have monitoring methods and performance standards or were unable to locate the documents that would have had them. Across oyster mitigation projects that did have monitoring methods and/or performance standards, common methods and standards were related to oyster density, shell height, and area. All projects with methods and/or standards required in-situ monitoring (no acoustic or aerial surveying). Among third-party preservation sites with oyster presence, a few providers had chosen to measure density or other attributes of the oysters present. Only a few projects stipulated comparison of oyster mitigation areas with reference areas. Performance standards for those projects required that the mitigation area must have similar or better recruitment and survival to a nearby reference area. In-situ monitoring required shell height measurements. Shell height is measured in centimeters from the hinge to the top of the shell and measurements are used to bin oysters into size classes (typically spat, juvenile, and adult or simply small and large). Young (<6 months) oysters typically experience higher mortality rates than adult oysters (Bartol et al. 1999), therefore collecting data on size classes can help gain insight into the pressures a given population is experiencing. Several projects took qualitative measurements of oyster-associated organisms, such as fish, sessile organisms, oyster predators (in particular, oyster drills and boring sponges), and fouling organisms. These projects also had qualitative performance standards, such as 'improving water quality and habitat in the area' or 'wild oyster recruitment and survival'. One project tested for common oyster diseases caused by the parasites Haplosporidium nelsoni and Perkinsus marinus. Another project measured volume of brown and black shell, which is a proxy for whether reef substrate is buried and therefore unavailable for colonization (black) or temporarily covered in mud (brown). Several projects had construction-type performance standards, such as 'shell must be distributed across the mound structure' or 'oyster bed establishment will be considered successful when the concrete base is 18 inches high'. Finally, several projects measured the proportion of live to dead oysters present. Voluntary restoration and ambient monitoring Although monitoring methods and performance standards were not available for every oyster mitigation site, when sites did have them, methods and standards (summarized in Box 3) were similar to those from voluntary restoration and ambient monitoring sites. Additionally, unlike seagrass projects, several oyster ambient monitoring/voluntary restoration projects had performance standards. Examples of nationwide ambient monitoring programs include NOAA's NERRS program, which monitors oysters on at least four of its 29 reserves. Although several reserves are monitoring the eastern oyster, one west coast reserve is monitoring the Olympia oyster. In terms of regional programs, in Chesapeake Bay, spurred by the Chesapeake Bay Agreement 25 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 (2014) and Executive Order 13508, oyster restoration in ten tributaries began in 2012 and is currently ongoing. The restoration efforts differ by tributary. In some, juvenile oysters and substrate (cultch or rock) are deployed. In others, only cultch is deployed for wild juvenile oysters to attach to. Another large restoration project, Half Moon Reef, is located in Matagorda Bay on the Texas coast. This project, which began in 2014, uses limestone as substrate and has a hybrid approach: half the reef is a sanctuary, and the other half is open to commercial harvest. There were three other examples of statewide programs, all of which monitor ambient populations: the Maryland Department of Natural Resources annual fall oyster recruitment survey (a historic survey initiated in the 1950s), the North Carolina Department of Marine Fisheries oyster sanctuary survey, and the FL DEP Aquatic Preserve program. The FL DEP program has 41 sites and monitors many habitats, including oysters if they are present. Across the nation, oyster restoration is popular and in the public eye; and there is no shortage of smaller projects than those represented here that involve restoration or monitoring of ambient populations. Box 3- Common practices for monitoring oyster mitigation sites Common monitoring metrics: Density, shell height, area Other monitoring metrics: Proportion of live to dead oysters, amount of surface and buried shell, oyster disease presence, natural recruitment, qualitative assessments of associated reef organisms and fouling Monitoring types: In-situ survey Performance standards: Area and height goals for reef base (construction-type specifications), density goals, similar recruitment and survival to a nearby reference reef 26 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Results: Tidal flats Third-party mitigation There were 24 third-party mitigation providers (17 banks, seven ILFs) with tidal flat presence at their sites. The age of the sites ranged widely; one bank was established in 1998 while another bank is currently building their site (as of 2021). More providers were restoring, enhancing, or creating tidal flats as opposed to preserving them (about 15 as opposed to 9), and banks tended to restore, create, or enhance tidal flats while ILFs tended to preserve them. Often, tidal flats were not the main focus of a given mitigation project, but part of a mosaic of estuarine or marine habitats. For some projects, this made it difficult to determine the compensatory mitigation method (restoration, enhancement, establishment, or preservation). Most of the providers that restored, created, or enhanced tidal flats were enhancing or restoring them by removing a tidal restriction from a wetland complex. A few providers had different approaches. One enhanced tidal flat by adding shell to enhance infauna and epifauna plant and animal communities and another created tidal flat for salmon habitat. Preservation sites with tidal flats ranged from marshes with intertidal channels, to barrier island habitats known for being migratory bird habitat, to expansive tidal flats in areas with a large tidal range. Tidal flat mitigation projects (third-party or PRM) reviewed in this section occurred in the states in shown in red. Monitoring and performance Most third-party and PRM projects' tidal flat components were not assigned distinct monitoring methods or performance standards. A few had performance standards Figure 4- A mudflat in New Jersey, photo by Mark Renna. Permittee-responsible mitigation There were only four PRM sites with tidal flats, and all were establishment, enhancement, or restoration projects. One of the sites also had a tidal flat preservation component. All were permitted somewhat recently, between 2006 and 2017, and were in California and Washington. Although two projects did not report the size of the tidal flats (or the documentation obtained did not state it), the other two projects' tidal flat areas were large (4.33 and 9.40 acres). Two projects created tidal wetland areas with salt marsh, fringing tidal flats, and intertidal channels. One of the projects used dredged material for construction. Another project rehabilitated an existing tidal flat but did not go into detail about the methods (or the documentation obtained did not state the methods). Impact types included bridge replacement projects and roadway improvement and re-grading projects. 27 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 related to construction specifications (measuring acreage and hydrology by measuring elevation and inundation). Tidal flats were often co-located with marsh restoration, which required monitoring and had quantitative performance standards. Tidal flat preservation projects had very limited monitoring; the extent of which was establishing photo points, removing trash, looking for anthropogenic impacts on the site, and taking notes on general site conditions. If tidal flats were monitored, it was usually in-situ, although a few projects took aerial photos. Other monitoring methods- Several tidal flat mitigation projects had more varied monitoring methods, although they were often qualitative and most did not have accompanying performance standards. A few projects sampled infauna, epifauna, surveyed bird usage, and seined for fish when there was water overlying the tidal flats, and one project compared these values to a reference site. A few projects measured water quality when the flats were inundated with water. One project made observations of algal growth on the flats. Three related sites (owned by the same mitigation provider) had performance standards for hydrology and non-native plant presence. At two of the three sites, photo points were established for time-lapse photos of a tidal cycle, a tidal gauge was placed to monitor tide height, and observations of erosion were noted. Two sites sampled sediment and fish and invertebrate tissue for heavy metals, in accordance with state guidance. Voluntary restoration and ambient monitoring No monitoring programs for which tidal flats were the sole focus were found within voluntary restoration and ambient monitoring. Therefore, it was not possible to compare monitoring methods and performance standards for tidal flats to compensatory mitigation. There are several programs that use aerial survey data to map wetlands and soil types (Fish and Wildlife Service's National Wetlands Inventory, Natural Resource Conservation Service's soil survey, and NOAA's Coastal Change Analysis Program), and although the data may capture tidal flats, they do not provide meaningful information about their characteristics or condition. Regional examples were also sparse, but one restoration and one research project were found. In southern California, a consortium of federal, state, and non-profit partners is currently restoring mudflats in the San Elijo Lagoon. These groups are planning to monitor the abundance and diversity of birds, fishes, and invertebrates, and to monitor water quality overlying the intertidal flats (San Elijo Lagoon Restoration 2021). Finally, U.S. Geological Survey (USGS) executed a tidal marsh sea level rise modeling survey that required field data collection at nine sites in Washington and Oregon, some of which included tidal flats. Monitoring included delineations of tidal mudflat area, gathering elevation data, and inundation frequency (Thorne et al. 2015). 28 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Box 4- Common practices for monitoring tidal flat mitigation sites Common monitoring metrics: Construction-type specifications (as-built area, tidal hydrology), taking photos, informal monitoring for human disturbance Other monitoring metrics: Infauna and epifauna abundance and diversity, water quality measurements, fish population surveys, heavy metal presence in sediment and fish, qualitative assessments of bird foraging Monitoring types: In-situ survey, aerial survey Performance standards: Mainly construction-related (area, hydrology) 29 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Results: Shallow water Third-party mitigation projects There were 32 third-party mitigation providers (22 banks, 10 ILFs) from states across the country with shallow (subtidal) water at their sites. It was very difficult to tell whether waters were subtidal at providers' sites from RIBITS documentation, most required follow-up with a bank or ILF representative. The age of the sites ranged from 1996 to not-yet-completed (as of 2021). Most providers restored, enhanced, or created shallow water. There were few projects that preserved shallow water exclusively (about six of the 32). Most restoration, enhancement, and establishment projects involved reconnecting waterways via removal of tidal restrictions by creating channels and removing fill. Examples of tidal restrictions found in third-party documentation included mosquito ditching, rice farming impoundments, dikes, and former roadway construction. One provider improved benthic habitat and water quality of shallow water areas by remediating sediment by neutralizing polyaromatic hydrocarbon (PAH) contaminants. A few providers created shallow water by converting uplands. Several providers created seagrass or oyster areas. When providers preserved shallow water habitat, it was generally part of large, multi-acre wetland complexes. Permittee-responsible mitigation projects The 34 PRM projects that included shallow water habitat were permitted between 2003-2019. Projects occurred across Florida, Texas, California, and Washington, though the majority of the projects were in Washington (26 projects). Of the Washington P RM projects, most were small (<0.1 acre), although a few were larger (<1 acre). Several of the Florida, Texas, and California projects did not have sizes listed; the projects that did ranged widely in size from 0.004 to 10 acres. One project removed derelict fishing gear from a 581-acre open water area, however, the actual mitigation footprint was not listed and would have been much smaller. Like the third-party projects, most PRM projects restored, enhanced, or created shallow water rather than preserving it. In Washington, the most common compensatory mitigation project types were removal of creosote-treated pilings, removal of subtidal or intertidal debris, removal of overwater structures such as docks, and placement of gravel to enhance forage fish spawning habitat. Creosote piling, intertidal and subtidal debris, and overwater structure removal frequently occurred nearby or on the same site as the impact. Debris removal included items such as 30 Shallow water mitigation projects (third-party or PRM) reviewed in this section occurred in the states in shown in red. Figure 5- Example of a shallow water impact- installation of poles for power lines. Photo from a Jacksonville district permit. ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 fishing gear (nets, crab pots), old bulkhead and boat ramp material (concrete, other rubble), tires, and a grounded vessel. One other mitigation project included establishment of a 'shoreline cutback' to create shallow water. Compensatory mitigation projects from Florida, Texas, and California involved rehabilitating a former dredged material storage site and restoration of channels and lagoons that were part of wetland complexes. One permittee planned to construct a stormwater treatment system, and two removed tidal restrictions. Several projects removed derelict structures, including creosote pilings and unused riprap. The majority of the impacts were from the building of docks and associated structures at private residences. There were also several public projects, including installing public utility structures, building boat ramps, parks, seawalls, a military facility, bridge building and repair projects, and one channel dredging project. Finally, the few commercial impacts included bulkhead repair and pier-building projects. Monitoring and performance Many (about half) of the third-party mitigation providers did not have monitoring methods or performance criteria for shallow water areas. Monitoring across PRM projects was simple, and most projects did not have performance standards. The most common monitoring methods and performance standards for PRM projects were taking photos and requiring submittal of documentation that demonstrated compensatory mitigation was complete. A few projects also required monitoring for adequate hydrology and collection of qualitative information on wildlife use of the area (however, this was not always exclusive to the shallow water habitat area present at the site). Water quality monitoring, fish surveys, or other monitoring of shallow water characteristics were not required in any of the PRM projects assessed. Monitoring methods and performance standards for third-party providers' sites were often written such that it was difficult to determine whether they applied to shallow subtidal water areas exclusively, or to intertidal areas, tidal flats, vegetated areas, or the general wetland complex. Following up with bank or ILF representatives did not always provide clarification, so it is possible that some of the following monitoring methods and performance standards may have been geared more toward intertidal than subtidal areas. Most third-party monitoring and performance standards centered around hydrologic conditions and water quality measurements. Providers measured hydrologic characteristics by collecting water level, temperature, and salinity data from tide gauges and sensors and by taking photos during the tidal cycle. A few providers took water quality measurements using basic parameters (salinity, temperature, pH, dissolved oxygen) from fixed stations or on surveys at regular intervals. Several providers monitored wildlife in the shallow water areas at their sites. Fish population characteristics (diversity, abundance) were measured using dip nets, traps, and seining. One provider divided fish present into feeding guilds and tropic position. The same provider also monitored the wading bird population. A different provider monitored salinity and fish populations to understand whether hydrologic modifications offsite were affecting fish populations. Many of the providers monitoring wildlife established performance standards and reference sites for the comparison of compensatory mitigation site data. 31 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 A few unique shallow water enhancement, restoration, and establishment projects are highlighted herein. One provider that remediated sediment monitored the restoration area by testing sediment samples and fish tissue for PAH concentrations and monitored benthic infauna for abundance, diversity, and biomass. The performance standard was a sediment PAH concentration below a set threshold. Another provider who was restoring a tidal connection had the most complex monitoring methods and performance standards of any shallow water mitigation project: the provider measured hydrology, water quality, fish and wading bird populations, chlorophyll in the water column (as a proxy for algal presence), light transmittance, and abundance and diversity of infauna. Each monitoring parameter had a specific threshold to be met in relation to a reference site. Voluntary restoration and ambient monitoring A variety of project types within both compensatory mitigation and voluntary restoration and ambient monitoring made it difficult to compare monitoring methods an performance standards. Water quality improvement projects in shallow estuarine and marine waters are being conducted across the U.S. at the national, regional, and local levels. Examples of nationwide water quality testing programs that include monitoring in estuarine and marine habitats include EPA's National Aquatic Resource Survey programs (National Wetland Condition Assessment and the National Coastal Condition Assessment). The NOAA NERRS and EPA NEP sites also measure water quality at many of their sites via fixed stations or on surveys at regular intervals. Examples of regional water quality monitoring programs include the NPS Eutrophication survey, the FL DEP Aquatic Preserve Program, as well as many state-specific coastal water quality monitoring programs. There are also many programs that purport to improve shallow water in ways other than improving water quality, such as the Maryland Artificial Reef Program, which sinks structures to create fish habitat in the Chesapeake Bay and in shallow coastal areas on the ocean side of the state. Another example is the California Coastal Conservancy, which maintains a program that removes creosote pilings from San Francisco Bay. Creosote- contaminated sediments and pilings negatively affect fish by causing lesions and problems with spawning (Malins et al. 1985, Vines et al. 2000). Box 5- Common practices for monitoring shallow water mitigation sites Common monitoring metrics: Water quality monitoring hydrologic monitoring via tide gauges, fish diversity Other monitoring metrics: Reef-associated organism species diversity and size class, sediment toxicity, fish tissue toxicity, sediment infauna abundance and diversity, light levels, oxidation/reduction potential Monitoring types: In-situ survey, sonar survey Performance standards: Varied from project to project and were not consistent 32 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 ¦ V . i. ¦ 111. i The goal of this report was to review compensatory mitigation in estuarine and marine habitats, which are less prevalent than freshwater wetlands and streams within the 404 Program. The search results showed that estuarine and marine habitats were present across 21 of 23 coastal states at 2% of banks, 21% of ILF programs, 9% of ILF program sites, and represent 5% of PRM permit actions. Limitations of the search- This report represents a comprehensive compilation of nationwide third-party mitigation that has been tracked in RIBITS and involves estuarine or marine habitats. However, the goal of finding comprehensive PRM from five states was not achieved. The search results could not generate a complete inventory of PRM involving the focal habitats because of blank fields and missing information in the DARTER database and incomplete documentation provided by USACE districts. Consequently, the permits obtained likely represent only a fraction of the PRM that has occurred involving the focal habitats. An example illustrates how many PRM projects may have been missed: Florida Fish and Wildlife Service collected 130 USACE Jacksonville district permits over a five-year period for seagrass impacts (personal communication with Margaret Hall; projects referenced in Rezek et al. 2019); however, only 13 were obtained via this report's search process, which spanned 12 years. As another example, the California Eelgrass Mitigation Policy references 66 eelgrass mitigation projects in Southern California alone over the past 35 years (NMFS 2014), while only eight were found from this report's search. Therefore, although the PRM results in this report can inform mitigation work and policy, they do not provide a complete picture of estuarine and marine mitigation projects occurring nationwide that involve seagrass, oysters, tidal flats, and shallow water. The perception of the 404 Program as only wetlands- The 404(b)(1) Guidelines (EPA 1980) emphasize the value of habitats that are not traditionally considered to be wetlands, such as vegetated shallows, sanctuaries, refuges, and mudflats. However, 404 Program practitioners historically have tended to associate the CWA 404 Program with wetlands, but not subtidal and unvegetated intertidal coastal areas. Perhaps consequently, and because it has been common with wetland mitigation projects, the 404 Program has historically focused on emergent vegetation when creating an estuarine or marine compensatory mitigation project or assessing its success. A specific focus on emergent or terrestrial vegetation for evaluating wetlands and riparian areas may be partially responsible for the infrequent requirement for compensatory mitigation for submerged and unvegetated habitats. Several of the permits that were reviewed authorized discharges of dredged or fill material that would impact tidal flats, but did not propose compensatory mitigation, stating that the impact areas were not jurisdictional waters of the United States. One permit stated that the proposed project, which was sited in shallow water, would not affect any aquatic resources that would require compensatory mitigation. Many other projects found during this research included CWA 404 permits issued for activities that would impact shallow water and intertidal areas, and yet compensation did not appear to be required. Moreover, many projects included monitoring methods and performance standards for vegetated intertidal 33 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 or subtidal areas but excluded unvegetated areas that were part of the same compensation project. Several compensatory mitigation projects converted tidal flat into salt marsh. Finally, two permits that were reviewed identified tidal flats on the impact site as special aquatic sites under the 404(b)(1) Guidelines, but the impacts were ultimately compensated with out-of-kind mitigation. The exclusion of some estuarine and marine habitats from requirements for compensatory mitigation, together with a broad lack of recognition of the important functions of and compensation opportunities for these habitats, will continue to result in impacts, habitat fragmentation, and cumulative degradation. Credit types and categorization in RIBITS- At present, although a simple RIBITS search for estuarine and marine credits will elicit many of the banks, ILFs, and ILF sites that exist nationwide, it will not reveal every provider and site with estuarine or marine habitat. This is because RIBITS uses a mixture of Cowardin Classification and more general terms (such as 'wetland') to describe credit types. To find an up-to-date record of estuarine and marine sites in RIBITS, several different searches were conducted, in addition to reading through documentation from the cyber repositories and engaging in follow-up discussions with bank and ILF representatives. This credit type issue is exacerbated when searching for habitats more specific than just estuarine or marine, such as seagrass. For instance, although 12 providers (banks or ILFs) had seagrass presence at their sites, a RIBITS search revealed only one, and although 24 providers had tidal flat presence at their sites, none were returned when "tidal flat", "mudflat," or "mud flat" was searched. The lack of standardized naming conventions for habitat types in RIBITS made this type of investigation more difficult, but more importantly, it creates a barrier for permittees searching for in-kind compensatory mitigation for their estuarine and marine impacts. Additionally, a small number of sites were not in RIBITS because they were old or simply had never been uploaded. Other barriers to mitigation for specific habitats- Documentation for third-party and PRM sites often did not include a clear description of tidal flat or shallow water presence, especially when these habitats were part of a mosaic of other habitats such as salt marsh. These projects also did not measure area of these habitats, and instead, their presence was recorded as part of the total area of the mitigation project. This practice precludes tracking of how the habitat is changing over time and of its suitability for being used as compensation. Oyster and seagrass area was measured more often than tidal flat and shallow water in the projects analyzed. Simple ratios, calculator tools, and assessment methods have been developed to assist permittees and regulators translate impacts to compensatory mitigation required (e.g. Chiavacci et al. 2022). There are calculator tools that recognize the presence of oysters, seagrass, tidal flats, and shallow water (e.g., the Interim Hydrogeomorphic functional assessment developed for Galveston District), and guidance documents that provide detail on best mitigation practices, some of which include simple ratios (e.g., the California Eelgrass Mitigation Policy and Florida's Guidance on Surveys for SAV Compensatory Mitigation Projects). Despite these tools, however, the authors of this report are not aware of any assessment methods that measure attributes of these habitats and attempt to translate them into credits. 34 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Seagrass, oyster, tidal flat, and shallow open water assessment methods for compensatory mitigation purposes should be developed. These assessments should calculate how much compensation a mitigation site has provided or how much compensatory mitigation will be required to offset a specific impact. At present, there are a few assessment methods that acknowledge the presence of the focal habitats, but none that consider their attributes (for example, density and shell height of oysters) for making mitigation decisions. There is a wide body of seagrass and oyster restoration data available, as well as detailed state-level seagrass mitigation guidance (Hinton A and B 2020, NMFS 2014) that would make developing assessment methods a straightforward task. For tidal flats and shallow water, assessment methods should be developed that consider a lack of traditional structure, and instead emphasize other attributes, such as infauna presence or water quality thresholds. Lack of monitoring and standards at preservation sites- Most third-party preservation projects did not have quantitative performance standards or monitoring beyond photo points and occasional surveillance. Although mitigation projects are designed to be self- sustaining, the sustainability of a preservation site cannot be measured if baseline information is not captured. Further, without habitat delineations and measurements such as water quality, a site could become degraded such that compensation is no longer equivalent to the impact, but no corrective actions would be required. Seagrass mitigation observations- The information compiled in this study suggests that compensatory mitigation for seagrass impacts is better established compared to the other focal habitats. Seagrass mitigation projects' monitoring methods and performance standards were usually thorough and aligned with typical monitoring and performance standards used in voluntary restoration/ambient monitoring projects. Additionally, multiple localities (FL, CA, OR, Chesapeake Bay, New England District) have developed compensation guidance for SAV impacts (Hinton A and B 2020, Oregon Department of State Lands 2019, USACE New England District 2020, NMFS 2014, and Chesapeake Bay Program 1995). In California, a state with many well-documented eelgrass mitigation projects, the failure rate of transplantation is 13% (NMFS 2014), which prompted the California Eelgrass Mitigation Policy (CEMP) to establish 1.2:1 as the minimum restoration threshold for a mitigation area. Oyster mitigation observations- Monitoring methods and performance standards for oyster areas were not common among third-party sites, but several PRM sites did not appear to have them. However, the PRM aspect of this report had a small sample size and therefore it is unclear how often oyster PRM occurs without monitoring or performance standards. Regardless, creating oyster habitat without establishing plans to monitor it first is not recommended. Oyster restoration is complex, and factors for project failure include, but are not limited to, predation, shell stock depletion, and lack of recruitment (Mann and Powell 2007). Mitigation providers and restoration practitioners may view the establishment of structure to be a net benefit whether wild oysters eventually recruit to it or not; however, this hands-off approach precludes gauging the success of the project. Tidal flat mitigation observations- Tidal flats were frequently present among third-party providers with estuarine or marine habitat (24 of 54 providers), but very few had associated monitoring methods or performance standards. Most projects (third-party and 35 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 PRM) restored, enhanced, created, or preserved tidal flats as part of a mosaic of estuarine wetlands rather than focusing on tidal flats exclusively. In permit documentation, several permittees mentioned that existing tidal flat was previously disturbed and therefore low value, especially if it was constructed from dredged material. Tidal flats can be labeled as low-value resources because of their lack of structure (that is visible to the human eye), which is thought of as the cornerstone of habitat. Media attention is greater and therefore public perception is better for some coastal habitats compared to others, which consequently makes them favored for protection and research (Duarte et al. 2008). Tidal flats rank low on this list, with some considering them "barren" or "stinky" (Faris 1990 or Melinkoff 1990 for example). A decade ago, seagrass was labeled the "ugly ducking" in this regard (Duarte et al. 2008). In this report's review of compensatory mitigation projects, tidal flats were often characterized as secondary, less-desirable habitats that are unable to sustain vegetation. Shallow water mitigation observations- PRM documentation appeared to show that compensatory mitigation requirements for shallow water impacts are inconsistent around the country. Twenty-eight permits for shallow water projects in the Seattle district were obtained, but only eight from the five other districts combined. If other districts were also requiring compensatory mitigation for impacts to shallow water, a similar number of projects should have been obtained. Additionally, in many of the reviewed projects, it was difficult to discern whether shallow subtidal water was present because of a lack of description of the mitigation areas and a lack of depth measurements. It is not surprising that the 404 Program has struggled with marine and estuarine shallow water compensation. First, because establishment of shallow water habitat would be at the expense of other habitats (terrestrial or aquatic) and second, public perception is such that unstructured habitats are often not regarded to be as desirable as structured habitats. However, compensation, ideally in-kind, should be required for impacts to shallow water; this could be carried out by improving existing subaqueous areas. The diverse suite of projects reviewed in this report demonstrate a variety of options available for shallow water improvement. For example, the Seattle district is allowing removal of over and in- water structures, including creosote pole removal and derelict vessel removal, in areas both on and off-site with respect to the impact. Two other districts approved large-scale projects to remove derelict crab pots as compensatory mitigation. One ILF is remediating sediment formerly contaminated with creosote. Other projects are installing stormwater filtration devices to improve water quality and installing pea gravel to improve fish spawning habitat. Tidal restriction removal projects are also common across the country. Finally, mitigation providers have been authorized to add substrate (often to create artificial reef structures) but also to remove substrate for the stated purpose of improving shallow water areas. For example, one ILF is constructing an artificial reef from stone and concrete with the intent of attracting fish and sessile invertebrates, while a PRM site removed stone riprap and described it as "creation of benthic habitat." An important consideration when deciding to add substrate is whether subtidal structure previously existed in the area. A critical perspective of artificial reef programs would be that without 36 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 rigorous monitoring and performance criteria, they are essentially a means of material disposal. Further challenges these habitats face- It is important to note that successful restoration of seagrass, oyster, tidal flat, and shallow water habitat faces many challenges, including sea level rise, non-native species presence, and warming temperatures. Although studying sea level rise implications was not an objective of this report, several third-party providers have pending projects that take sea level rise into account. One project involves high and low salt marsh vegetation and the ability for the marsh to migrate landward. Another project proposes to continually excavate uplands to match sea level rise for seagrass mitigation, since the deeper edges of the beds would die off with increased depth of overlying water. In the Pacific Northwest, regulators and mitigation providers are already grappling with non-native species. One PRM applicant did not propose and was not required to mitigate for impacts to non-native eelgrass [Z. japonica). A third-party provider with extensive populations of a non-native oyster [C. gigas) is currently debating whether to use the oyster areas for mitigation credits. Future research- Interested researchers should continue compiling information on marine and estuarine compensatory mitigation, as well as information about other, lesser- known habitats that could be affected by the issuance of CWA Section 404 permits. Documentation alone will not be enough to understand project and compensation outcomes, and future researchers should plan to reach out to agency staff and mitigation providers for additional details and context. 37 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Recommendations Improving mitigation practices The use of standardized assessment methods, monitoring metrics and performance standards for oyster, seagrass, tidal flat, and shallow water habitat can lead to more efficient review of permits and compensatory mitigation proposals in addition to improved performance at mitigation sites. The following recommendations could also improve compensatory mitigation outcomes: 1. For tidal flat habitat: • Develop a clear definition of tidal flats (currently, there is confusion about whether marsh edges, tidal creeks, unvegetated portions of living shorelines, intertidal areas seaward of bulkheads, and other intertidal areas are tidal flats). • Identify and assess tidal flats at impact sites, and where appropriate require compensatory mitigation. • Assess tidal flats at impact sites that are constructed of dredged materials, do not assume they are degraded. 2. For shallow water habitats: • Identify and assess shallow water at impact sites, and where appropriate require compensatory mitigation. • Consider the many creative solutions for providing in-kind compensatory mitigation for shallow water impacts that have been implemented, such as sediment rehabilitation, removal of debris and creosote piles, placement of habitat gravel, installation of stormwater treatment devices, and restoration of tidal connections. 3. Include monitoring and performance standards for seagrass, oysters, tidal flats, and shallow water when they are present at preservation sites. 4. For seagrass and oyster mitigation projects, draw project ideas, monitoring methods, and performance standards from the wide body of literature and data that is available from voluntary restoration projects. 5. When seagrass, oysters, tidal flats, or shallow water habitat is part of a mosaic of habitats affected by an impact OR established, restored, enhanced, or preserved for compensatory mitigation, the footprint (area) of each of these habitats should be measured to ensure accurate crediting. 6. Consider the history of nonpoint sources and other unregulated impacts on an area's current presence of oysters, seagrass, tidal flats, and shallow water. Improving documentation and record-keeping Including the appropriate markers for aquatic resource type (for instance, Cowardin classification) when tracking permitted impacts and compensatory mitigation projects is essential to enable anyone beyond those directly involved in the project to find it. The ability to learn from compensatory mitigation practices over time also depends on the availability of relevant information in project files, especially the approved mitigation plan, 38 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 monitoring reports, and instrument or MFR. This report was made possible because of the many regulators across the country who took the steps necessary to appropriately fill in this documentation, even when it was not mandatory, however, many projects and their lessons were missed. Recommendations for ensuring that documentation will support future discovery by regulators looking for examples or others studying regulatory practices are: 1. Ensure the Cowardin classification field is populated for: • For PRM- Impacts and mitigation entries in the ORM database. • For third-party mitigation: all RIBITS credits. 2. Make mitigation documentation digitally accessible, especially: • For PRM- the permit, mitigation plan, MFR, and monitoring reports • For third-party mitigation- the instrument, instrument modifications, mitigation plans, and monitoring reports 3. Monitoring reports should include the monitoring methods and performance criteria that were required in the permit, mitigation plan or bank/ILF instrument, for reference and in case documentation is seperated. 4. Monitoring methods and performance criteria should be included in a defined section(s) in the permit, mitigation plan or bank/ ILF instrument. 5. Develop templates for bank or ILF instruments that include descriptions of all habitat types present at mitigation sites, maps, and corresponding tables that clearly identify credit types and the habitats they represent. Next steps for research Like the field of environmental restoration, the field of compensatory mitigation is multifaceted and ever evolving. Advancements in research often lead to improvements in compensatory mitigation practices and assessments. Compiling this report revealed an array of agency staff, students, academics, and stakeholders who were in the process of researching compensatory mitigation related topics. Future research to inform compensatory mitigation practices for oyster, seagrass, tidal flat, and shallow water habitats include: 1. Develop assessment methods that can be used for regulatory purposes for seagrass, oyster, tidal flat, and shallow water habitats. The methods must be able to assess changes at impact and compensatory mitigation sites. 2. Develop monitoring methods and performance standards unique to tidal flat compensatory mitigation projects. Ideas include aerial photos and mapping, water quality measurements when the area is submerged, area and elevation measurements, sediment properties like grain size or toxic substance concentration, biological properties such as algae or infauna presence, and/or wading or migratory bird usage. 3. Develop monitoring requirements and performance standards unique to shallow water mitigation projects. Ideas include tracking water quality (standard parameters like salinity, temperature, dissolved oxygen, and pH but also chlorophyll and suspended 39 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 solids, which may require laboratory analysis), toxic substance concentration of sediments, light penetration, and fish abundance, diversity, and/or health. 4. Assess restoration success at a variety of locations to inform setting appropriate mitigation ratios for different habitat types. For seagrass, success rates and mitigation ratios are available in the California Eelgrass Mitigation Policy (NMFS 2014). Several projects featured in this report buffered against seagrass variability by planting an area greater than the impact site (a higher ratio of compensation to impact). Training opportunities Training on seagrass, oyster, tidal flat, and shallow water habitats is needed. Potential training topics include functions and services, applicability of the CWA Section 404 requirements, and how to assess and compensate for impacts to each habitat. 40 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 References Aoki, L. R., McGlathery, K. J., Oreska, M. P. (2020). Seagrass restoration reestablishes the coastal nitrogen filter through enhanced burial. Limnology and Oceanography, 65(1), 1-12. Bartol, I. K., Mann, R., Luckenbach, M. (1999). Growth and mortality of oysters (Crassostrea virginica) on constructed intertidal reefs: effects of tidal height and substrate level. Journal of Experimental Marine Biology and Ecology, 237(2), 157-184. Bilkovic, D. M., Herschner, C. H., Rudnicky, T., Nunez, K., Schatt, D. E., Kileen, S., Berman, M. (2009). Vulnerability of shallow tidal water habitats in Virginia to climate change. Bell, S. S., Tewfik, A., Hall, M. 0., Fonseca, M. S. (2008). Evaluation of seagrass planting and monitoring techniques: implications for assessing restoration success and habitat equivalency. Restoration Ecology, 16[3), 407-416. Brown, B., Wilson Jr, W. H. (1997). The role of commercial digging of mudflats as an agent for change of infaunal intertidal populations. Journal of Experimental Marine Biology and Ecology, 218(1), 49-61. Chesapeake Bay Program (1995). Guidance for Protecting Submerged Aquatic Vegetation in Chesapeake Bay from Physical Disruption. Accessed 2-25-21: https://www.chesapeakebay.net/what/publications/guidance for protecting submerged afluat|c_veg esaneakeJba^l. Chiavacci, S.J., French, E.D., and Morgan, J.A., 2022, Database of biodiversity, habitat, and aquatic resource quantification tools used for market-based conservation in the United States (ver. 2.0, June 2022): U.S. Geological Survey data release, https .org/10.5066/F79G5M3X. Cowardin, L. M. (1979). Classification of wetlands and deepwater habitats of the United States. Fish and Wildlife Service, US Department of the Interior. Dahl, T.E. 2011. Status and trends of wetlands in the conterminous United States 2004 to 2009. U.S. Department of the Interior; Fish and Wildlife Service, Washington, D.C. 108 pp Dahl, T.E. and Stedman, S.M. (2013) Status and trends of wetlands in the coastal watersheds of the Conterminous United States 2004 to 2009. U.S. Department of the Interior, Fish and Wildlife Service and National Oceanic and Atmospheric Administration, National Marine Fisheries Service. (46 p.) Dennison, W. C., Orth, R. J., Moore, K. A., Stevenson, J. C., Carter, V., Kollar, S., Bergstrom, P. W., Batiuk, R. A. (1993). Assessing water quality with submersed aquatic vegetation. Bioscience, 43(2), 86-94. Duarte, C. M., Dennison, W. C., Orth, R. J., Carruthers, T. J. (2008). The charisma of coastal ecosystems: addressing the imbalance. Estuaries and coasts, 31 (2), 233-238. 41 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Faris, G. (1990, Jan 19). Disappearing coastal mudflats are 'the habitat of the overlooked'. Los Angeles Times, https://www.latimes.com/archives/la-xpm-199C e-144- ston, Fourqurean, J. W., Duarte, C. M., Kennedy, H., Marba, N., Holmer, M., Mateo, M. A., Aposotolaki, E. T., Kendrick, G. A., Krause-Jensen, D., McGlathery, K. J., Serrano, 0. (2012). Seagrass ecosystems as a globally significant carbon stock. Naturegeoscience, 5(7), 505. Fourqurean, J. W., Powell, G. V., Ken worthy, W. J., Zieman, J. C. (1995). The effects of long- term manipulation of nutrient supply on competition between the seagrasses Thalassia testudinum and Halodule wrightii in Florida Bay. Oikos, 349-358. Green, T. J., Siboni, N., King, W. L., Labbate, M., Seymour, J. R., Raftos, D. (2019). Simulated marine heatwave alters abundance and structure of Vibrio populations associated with the Pacific Oyster resulting in a mass mortality event. Microbial ecology, 77(3), 736-747. Greening, H. S., Cross, L. M., Sherwood, E. T. (2011). A multiscale approach to seagrass recovery in Tampa Bay, Florida. Ecological Restoration, 29(1-2), 82-93. Hargreaves, A. L., Whiteside, D. P., Gilchrist, G. (2011). Concentrations of 17 elements, including mercury, in the tissues, food and abiotic environment of Arctic shorebirds. Science of the Total Environment, 409(19), 3757-3770. Hettinger, A., Sanford, E., Hill, T. M., Russell, A. D., Sato, K. N., Hoey, J., Forsch, M., Page, H. N., Gaylord, B. (2012). Persistent carry-over effects of planktonic exposure to ocean acidification in the Olympia oyster. Ecology, 93(12), 2758-2768. Hinton, J. (2020). A. Guidance on Surveys for Potential Impacts to Submerged Aquatic Vegetation. Florida Department of Environmental Protection. https://floridadep.gov/rcp/beaches-inlets-ports/docur jance-survevs-potential- impacts-submerged-aauatic-vegetation. Hinton, J. (2020). B. Guidance on Surveys for Submerged Aquatic Vegetation Compensatory Mitigation Projects. Florida Department of Environmental Protection. https://floridadep.gov/rcp/beaches-inlets-ports/docur jance-survevs- submyergedbagyuat^^ Kellogg, M. L., Cornwell, J. C., Owens, M. S., Paynter, K. T. (2013). Denitrification and nutrient assimilation on a restored oyster reef. Marine Ecology Progress Series, 480,1-19. Kellogg, L., Brush, M., Cornwell, J. (2018). An Updated Model for Estimating the TMDL- Related Benefits of Oyster Reef Restoration. Virginia Institute of Marine Science and University of Maryland. Li, X., Bellerby, R., Craft, C., Widney, S. E. (2018). Coastal wetland loss, consequences, and challenges for restoration. Anthropocene Coasts, 1[ 1), 1-15. Lowe, M. R., Sehlinger, T., Soniat, T. M., La Peyre, M. K. (2017). Interactive effects of water temperature and salinity on growth and mortality of eastern oysters, Crassostrea virginica: 42 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 a meta-analysis using 40 years of monitoring data .Journal of Shellfish Research, 36(3), 683- 697. Malins, D. C., Krahn, M. M., Myers, M. S., Rhodes, L. D., Brown, D. W., Krone, C. A., McCain, B. B., Chan, S. L. (1985). Toxic chemicals in sediments and biota from a creosote-polluted harbor: relationships with hepatic neoplasms and other hepatic lesions in English sole (Parophiys vetulus). Carcinogenesis, 6(10), 1463-1469. Mann, R., and Powell, E. N. (2007). Why oyster restoration goals in the Chesapeake Bay are not and probably cannot be achieved. Journal of Shellfish Research, 26(4), 905-917. Melinkoff, E. (1990, Jan 6). Exposing the rich life in the mudflats. Los Angeles Times. https://www.latimes.com/archives/la 0-01-06-vw-385-story.html. McGlathery, K. J., Sundback, K., Anderson, I. C. (2007). Eutrophication in shallow coastal bays and lagoons: the role of plants in the coastal filter. Marine Ecology Progress Series, 348, 1-18. Moore, K. A., and Jarvis, J. C. (2008). Environmental factors affecting recent summertime eelgrass diebacks in the lower Chesapeake Bay: implications for long-term persistence. Journal of Coastal Research, (55), 135-147. National Oceanic and Atmospheric Administration and Bureau of Ocean and Energy Management (2019). Data Registry. Marine Cadastre.gov/data National Marine Fisheries Service (2014). California Eelgrass Mitigation Policy and Implementing Guidelines. Accessed 2-25-21: https://media.fisheries.noaa.gov/dammigration/cemp_oct_2014_final.pdf Newell, R. I., Fisher, T. R., Holyoke, R. R., Cornwell, J. C. (2005). Influence of eastern oysters on nitrogen and phosphorus regeneration in Chesapeake Bay, USA. In The comparative roles of suspension-feeders in ecosystems (pp. 93-120). Springer, Dordrecht. Newell, R. I. (2004). Ecosystem influences of natural and cultivated populations of suspension-feeding bivalve molluscs: a review. Journal of Shellfish research, 23(1), 51-62. Oregon Department of State Lands (2019). A guide to the removal-fill permit process. Accessed 3-1-21: https://www.oregon.gov/DSL/WW/Documents/Removal Fill Guide.pdf. Orth, R. J., Heck, K. L., van Montfrans, J. (1984). Faunal communities in seagrass beds: a review of the influence of plant structure and prey characteristics on predator-prey relationships. Estuaries, 7(4), 339-350. Pedersen M.F., Nielsen SL, Banta GT (2004). Interactions between vegetation and nutrient dynamics in coastal marine ecosystems: an introduction. In: Nielsen SL, Banta GT, Pedersen MF (eds) Estuarine nutrient cycling: the influence of primary producers, Kluwer Academic, Dordrecht, p 1-16 43 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Richardson, J. P., Lefcheck, J. S., Orth, R. J. (2018). Warming temperatures alter the relative abundance and distribution of two co-occurring foundational seagrasses in Chesapeake Bay, USA. Marine Ecology Progress Series, 599, 65-74. Ray, G. L. (2000). Infaunal assemblages on constructed intertidal mudflats at Jonesport, Maine (USA). Marine Pollution Bulletin, 40(12), 1186-1200. Reimer, J. D., Yang, S. Y., White, K. N., Asami, R., Fujita, K., Hongo, C., Shingo, I., Kawamura, Maeda, I., Mizuyama, M., Obuchi, M., Sakamaki, T., Tachihara, A., Tamura, A., Tanahara, A., Yamaguchi, A., Jenke-Kodama, H. (2015). Effects of causeway construction on environment and biota of subtropical tidal flats in Okinawa, Japan. Marine Pollution Bulletin, 94(1-2), 153-167. Reilly, F. J., Spagnolo, R. J., Ambrogio, E. (1999). Marine and estuarine shallow water science and management: The interrelationship among habitats and their management. Estuaries, 22(3), 731-734. Rezek, R. J., Massie, J. A., Nelson, J. A., Santos, R. 0., Viadero, N. M., Boucek, R. E., Rehage, J. S. (2020). Individual consumer movement mediates food web coupling across a coastal ecosystem. Ecosphere, 11[ 12), e03305. Rezaie, A. M., Loerzel, J., Ferreira, C. M. (2020). Valuing natural habitats for enhancing coastal resilience: Wetlands reduce property damage from storm surge and sea level rise. PIoS one, 15[ 1), e0226275. San Elijo Lagoon Restoration (2021). Nature Collective. https://thenaturecollective.org/project/san-eliio-lagoon-restoration/. Short, F. T., Burdick, D. M., Kaldy, J. E. (1995). Mesocosm experiments quantify the effects of eutrophication on eelgrass, Zostera marina. Limnology and oceanography, 40(4), 740-749. Smithsonian (2018). Eelgrass wasting disease has new enemies: Drones and artificial intelligence. ScienceDaily. Retrieved December 16, 2020 from www.scieiicedaily.com/releases/2018/09/18091811Q956.litiTi. Stedman, S. M. and Dahl, T. E. (2008) Status and trends of wetlands in the coastal watersheds of the Eastern United States 1998 to 2004. National Oceanic and Atmospheric Administration, National Marine Fisheries Service and U.S. Department of the Interior, Fish and Wildlife Service. (32 pages) Thorne, K. M., Dugger, B. D., Buffington, K. J., Freeman, C. M., Janousek, C. N., Powelson, K. W., Gutenspergen, G.R., Takekawa, J. Y. (2015). Marshes to mudflats—Effects of sea-level rise on tidal marshes along a latitudinal gradient in the Pacific Northwest (No. 2015-1204). U.S. Geological Survey. U.S. Army Corps of Engineers New England District (2020). New England District Compensatory Mitigation Guidance. Accessed 10-4-21: 44 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 https://www.nae.usace.army.mil /Portals, ics/regulatory/Mitigation/Compensatory- Mitigation-SQP-2020.pdf?ver=EWhCrK70ZfmPr—8x0K51g%3d%3d. Vanderbilt, F., Martin, S., Olson, D. (2015). The Mitigation Rule Retrospective: A Review of the 2008 Regulation Governing Compensatory Mitigation for Losses of Aquatic Resources. U.S. Army Corps of Engineers Institute for Water Resources. Vines, C. A., Robbins, T., Griffin, F. J., Cherr, G. N. (2000). The effects of diffusible creosote- derived compounds on development in Pacific herring (Clupea paUasi). Aquatic Toxicology, 51(2), 225-239. Ward LG, Kemp W.M., Boynton W.R. (1984). The Influence of waves and seagrass communities on suspended particulates in an estuarine embayment. Mar Geol 59:85-103 Waldbusser, G. G., Voigt, E. P., Bergschneider, H., Green, M. A., Newell, R. I. (2011). Biocalcification in the eastern oyster (Crassostrea virginica) in relation to long-term trends in Chesapeake Bay pH. Estuaries and Coasts, 34(2), 221-231. Whitlow, W. L., and Grabowski, J. H. (2012). Examining how landscapes influence benthic community assemblages in seagrass and mudflat habitats in southern Maine. Journal of Experimental Marine Biology and Ecology, 411,1-6. Withers, K. (2002). Shorebird use of coastal wetland and barrier island habitat in the Gulf of Mexico. The Scientific World Journal, 2, 514-536. Wilberg, M. J., Livings, M. E., Barkman, J. S., Morris, B. T., Robinson, J. M. (2011). Overfishing, disease, habitat loss, and potential extirpation of oysters in upper Chesapeake Bay. Marine Ecology Progress Series, 436,131-144. 45 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Appendix A- Data and tables Table 1- Search Terms for third-party Mitigation in RIBITS Habitat Terms Tidal flat Tidal flat Mud flat Mudflat Seagrass Seagrass Sea grass Zostera SAV Submerged aquatic vegetation Widgeongrass Phyllospadix Syringodium Halodule Thalassia Halophila turtle grass eelgrass eel grass manatee grass shoal grass widgeon grass Oyster oyster crassostrea virginica ostrea lurida 46 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Table 2- Third-Party Mitigation Providers: Banks Reference # State Bank name Year bank established Focal Habitats Present 1 AK Natzuhini Bay Mitigation Bank 2004 Tidal flat, shallow water 2 AK Trillium Mitigation Bank 2019 Tidal flat 3 CA Colorado Lagoon Mitigation Bank 2020 Tidal flat, seagrass, shallow water 4 CA Navy Region Southwest San Diego Bay Eelgrass Mitigation Bank 2008 Seagrass, shallow water 5 CA Port of Los Angeles 2017 Shallow water 6 CA San Francisco Bay Wetland Mitigation Bank 2011 Tidal flat, shallow water 7 FL Bear Point Mitigation Bank 2004 None 8 FL CGW Mitigation Bank 2008 None 9 FL Florida Gulf Coast Mitigation Bank 2016 None 10 FL FP&L Everglades Phase I Mitigation Bank 2009 Seagrass, shallow water 11 FL Horseshoe Creek 2020 None 12 FL Little Pine Island Mitigation Bank 1996 Shallow water 13 FL Mangrove Point 2020 Tidal flat, oyster 14 FL North Florida Saltwater Marsh Mitigation Bank 2013 None 15 FL Tampa Bay Mitigation Bank 2008 Shallow water 16 GA T ronox 2008 None 17 GA Tucker Mitigation Bank 2000 Shallow water 18 GA Salt Creek Mitigation Bank 2017 None 19 LA Chef Menteur Pass Mitigation Bank 2010 Shallow water 20 LA Rockefeller Refuge A, B and C 2004 None 21 MS Rhodes Lake Mitigation Bank 2008 Shallow water 47 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Reference State Bank name Year bank Focal Habitats # established Present 22 NJ Evergreen Abbot Creek Mitigation Bank 2015 Tidal flat, shallow water 23 NJ Evergreen Great Bay Mitigation Bank 2018 Tidal flat, shallow water 24 NJ Evergreen MRI3 Mitigation Bank 2012 Tidal flat, shallow water 25 NJ Marsh Resources/Meadowlands 1999 Tidal flat, shallow water 26 NJ Richard P. Kane Wetland Mitigation Bank 2010 Tidal flat, shallow water 27 NJ Evergreen Stipson's Island Mitigation Bank 2011 Tidal flat, shallow water 28 NY NY City Small Business Services Saw 2018 Tidal flat, Mill Creek Mitigation Bank shallow water 29 OR Wilbur Island Mitigation Bank 2008 Shallow water 30 SC Clydesdale Mitigation Bank 2013 Shallow water 31 SC Congaree Carton 2005 Tidal flat 32 SC Murray Hill 2018 Shallow water 33 SC SCDOT Huspa Creek East and West Mitigation Bank Sites 1998 Tidal flat 34 TX Gulf Coastal Plains Mitigation Bank 2016 Tidal flat, shallow water 35 VA Chesapeake Land Development Tidal Bank 2004 T idal flat 36 VA Goose Creek 1982 None 37 VA New Mill Creek Tidal Mitigation Bank 2018 Tidal flat 38 WA McHugh Demonstration Wetland Bank 1999 None 48 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Table 3- Third-Party Mitigation Providers: ILFs and Sites Reference # State ILF name Year ILF established Number of marine/ estuarine sites Site Names Focal habitats present 1 AK Great Land Trust 2011 2 Fish Creek, Campbell Creek Tidal flat 2 AK Southeast Alaska Land T rust 1998 25 Auk Nu Cove Conservation Easement, Branta Lot 2, Crescent Bay Conservation Easement, Eagles Reach Lot 2, Eagles View Lot IB, Farragut Estuary Conservation Easement, Gandercall Lot 3, Gandercall Lot 4, Great Horned Owl Lot 2, Grey Goose Lot 2, HAKALA Lot 2, Hilda Creek & Accretion Conservation Easement, Hinz II Lot IB, Honsinger Wetlands, King Conservation Easement, Lazy G Acres Lot 2, Lobaugh Conservation Easement, Moon Meadow Lot 2, Morning Meadow Lot 3, Morning Meadow Lot 4, Nelson Homestead Conservation Easement, Sherry Lot 2, Sherry Lot 3, Sunny Point Park #3 Lot 1 & Lot 2, Wigeon Ponds Lot 2 Deed Restriction Seagrass, tidal flats, shallow water 3 AK The Conservation Fund AK 2010 5 AR-4, AR-1, SW-2, SW-3, SW-4 Seagrass, tidal flats 4 CT CT ILF program 2011 1 Stratford Point Oyster 5 FL Keys Environmental Restoration Fund 1998 Between 3-10* Lignumvitae Seagrass Scar 1999, Lignumvitae Seagrass Stake Array 1999, Lignumvitae Seagrass Sites 2005 Seagrass, shallow water 6 FL Keys Restoration Fund 2015 4 Bahia Honda A, Bahia Honda B, Crane Point Hammock, Lignumvitae Seagrass Seagrass, shallow water 49 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Reference # State ILF name Year ILF established Number of marine/ estuarine sites Site Names Focal habitats present 7 FL Northwest Florida Water Management District 2015 2 Dutex, Live Oak Point Shallow water, seagrass, oyster 8 MA MA Dept. of Fish and Game 2014 8 Upper Great Marsh, Rough Meadows, Town Farm, Eelgrass Restoration, Parker River Connector, Eelgrass restoration (Salem, MA), Oyster Reef (Nantucket) Seagrass, shallow water, oyster 9 ME Maine Natural Resources Conservation Program 2011 22 Whiskeag Creek, Indian River, Meadow Brook Wetlands, Brookings Bay, Maquoit Bay, Basin Cove/Curtis Cove, St. George River Tidal, Weskeag Wetlands, Mil Pond Tidal Restoration, Kate Furbish Restoration, Wallace Shore Road, Long Cove Wetlands, Parker Head Road, Little River Restoration, Old Pond- Demska, Middle Bay-Liberty, Smelt Brook Intertidal Restoration, Spring Point (Hog Bay), Fixing Furbish (Phase 1), Rouse island, Strawberry Creek, Willow Brook Culvert Replacement Tidal flat, seagrass 10 NC N.C. Dept of Mitigation Services 2010 9 Balance Farm, Hammock's State Park, Camp Lejeune, Sturgeon City, Lengyel, Sawmill, Bird Island, Maritime Museum, Pamlico Sound Oyster Reef Tidal flat, oyster, shallow water 11 NH NH Aquatic Resources Mitigation Program 2018 2 Cutt's Cove, SALMON-PISC Oyster Reef Oyster, shallow water 50 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Reference # State ILF name Year ILF established Number of marine/ estuarine sites Site Names Focal habitats present 12 OR OR Dept of State Lands 2009 3 Pixieland, Kilchis River Preserve, Tamara Quays Shallow water 13 VA Living River Restoration T rust 2018 2 Paradise Creek, Money Point Oyster, shallow water 14 VA Virginia Aquatic Resources Trust Fund 1995 19 Cumberland Marsh, Rappahannock Phragmites Control, Crows Nest (Phase 1], Crows Nest (Phase 2), VCU, Northwest River (Kellam Rigato), Dragon Run (Milby), Thompson, Hampton, Dameron Marsh, SAV Beds, SAV Beds 2, Virginia Coast Reserve (oyster restoration), New Point Comfort, Eastern VA Phragmites Control, Dameron Marsh, Church Neck, VMRC oyster reef, Lower Chickahominy River Seagrass, oyster, shallow water 15 WA Hood County Coordinating Council 2012 4 Anderson, Big Beef, Olson, Dewatto Tidal flat, seagrass, oyster 16 WA King County Mitigation Reserves 2011 1 Chinook Wind Mitigation Project Tidal flat *For the official tally of ILFsites, three rather than ten was used to be conseivative 51 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Table 4- Department of the Army Permits Reference # State DA NUMBER Mitigation habitat Year permit issued 1 FL SAJ-1999-03746 Shallow water 2003 2 FL SAJ-2003-04783 Shallow water 2015 3 FL SAJ-2004-01945 Seagrass 2010 4 FL SAJ-2004-08169 Shallow water 2007 5 FL SAJ-2005-05399 Shallow water 2018 6 FL SAJ-2008-04801 Seagrass 2012 7 FL SAJ-2010-00817 Seagrass 2013 8 FL SAJ-2013-00319 Oyster, shallow water 2013 9 FL SAJ-2014-02406 Seagrass 2015 10 FL SAJ-2014-03521 Seagrass 2017 11 TX SWG-2012-00203 Shallow water 2013 12 TX SWG-2 014-00905 Oyster 2014 13 CA SPL-2010-00028 Shallow water 2010 14 CA SPL-2010-01129 Seagrass 2011 15 CA SPL-2011-00463 Seagrass 2012 16 CA SPL-2012-00172 Tidal flat 2017 17 CA SPL-2013-00146 Seagrass 2013 18 CA SPL-2015-00569 Seagrass 2017 19 CA SPL-2015-00651 Seagrass 2016 20 CA SPL-2016-00825 Tidal flat 2017 21 CA SPN-2005-293680 Tidal flat 2006 22 CA SPN-2016-00053 Shallow water 2016 23 VA NAO-2001-03946 Oyster 2019 24 VA NAO-2003-01984 Oyster 2014 25 VA NAO-2010-02401 Oyster 2012 26 VA NAO-2014-00463 Seagrass 2014 27 VA NAO-2015-00310 Seagrass 2016 28 WA NWS-2010-00968 Tidal flat 2010 29 WA NWS-2011-00183 Shallow water 2014 30 WA NWS-2011-00761 Shallow water 2017 31 WA NWS-2012-00699 Shallow water 2013 32 WA NWS-2012-00759 Shallow water 2013 33 WA NWS-2012-01110 Seagrass 2014 34 WA NWS-2012-01175 Shallow water 2014 35 WA NWS-2013-00171 Shallow water 2014 36 WA NWS-2013-00419 Shallow water 2013 37 WA NWS-2013-01124 Shallow water 2013 38 WA NWS-2014-00159 Shallow water 2015 39 WA NWS-2014-00433 Shallow water 2015 52 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Reference # State DA NUMBER Mitigation habitat Year permit issued 40 WA NWS-2014-00804 Shallow water 2017 41 WA NWS-2014-00890 Shallow water 2016 42 WA NWS-2014-01177 Shallow water 2017 43 WA NWS-2015-00291 Shallow water 2015 44 WA NWS-2015-00601 Shallow water 2016 45 WA NWS-2015-00696 Shallow water 2016 46 WA NWS-2015-00971 Shallow water 2016 47 WA NWS-2016-002 00 Shallow water 2016 48 WA NWS-2016-003 20 Shallow water 2016 49 WA NWS-2016-003 24 Shallow water 2016 50 WA NWS-2016-00902 Shallow water 2017 51 WA NWS-2017-00809 Shallow water 2018 52 WA NWS-2012-01111 Shallow water 2013 53 WA NWS-2013-00213 Shallow water 2013 54 WA NWS-2013-00245 Shallow water 2015 55 WA NWS-2014-00736 Shallow water 2015 53 ------- Compensatory Mitigation in Estuarine and Marine Habitats Table 5- Ambient monitoring programs February 2023 Type Program or Survey Name Worldwide SeagrassNet program Zostera Experimental Network (ZEN) program National EPA NARS NCCA survey EPA NARS NWCA survey FWS Status and Trends/National Wetlands Inventory program National Park Service Eutrophication Survey NOAA NERRS program EPA NEP program Multi-State VIMS Annual Aerial Seagrass Survey 10 Tributaries by 2025 NOAA Oyster Restoration USGS Marshes to Mudflats project State Maryland DNR Fall Recruitment Survey Florida DEP Aquatic Preserve Program VIMS Long-Term Seagrass Transect Program North Carolina DMF Sanctuary Survey Seagrass restoration in Virginia's coastal bays San Elijo Lagoon Restoration project, California 54 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Table 6- California Eelgrass Mitigation Policy Performance Standards Month Standard 0 Monitoring should confirm the full coverage distribution of planting units over the initial mitigation site as appropriate to the geographic region. 6 Persistence and growth of eelgrass within the initial mitigation area should be confirmed, and there should be a survival of at least 50 percent of the initial planting units with well-distributed coverage over the initial mitigation site. For seed buoys, there should be demonstrated recruitment of seedlings at a density of not less than one seedling per four (4) square meters with a distribution over the extent of the initial planting area. The timing of this monitoring event should be flexible to ensure work is completed during the active growth period. 12 The mitigation site should achieve a minimum of 40 percent coverage of eelgrass and 20 percent density of reference site(s) over not less than 1.2 times the area of the impact site. 24 The mitigation site should achieve a minimum of 85 percent coverage of eelgrass and 70 percent density of reference site(s) over not less than 1.2 times the area of the impact site. 36 The mitigation site should achieve a minimum of 100 percent coverage of eelgrass and 85 percent density of reference site(s) over not less than 1.2 times the area of the impact site. 48 The mitigation site should achieve a minimum of 100 percent coverage of eelgrass and 85 percent density of reference site(s) over not less than 1.2 times the area of the impact site. 60 The mitigation site should achieve a minimum of 100 percent coverage of eelgrass and 85 percent density of reference site(s) over not less than 1.2 times the area of the impact site. 55 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Appendix B- Out-of-kind mitigation Introduction- The 2008 Mitigation Rule upholds a preference for in-kind (of the same type) mitigation to increase likelihood that the functions and services that are lost at the impact site will be gained at a mitigation site.10 Out-of-kind compensatory mitigation, however, can be considered if in-kind replacement is not possible, is unlikely to adequately compensate for the impact, or out-of-kind mitigation is environmentally preferable. For instance, out-of-kind mitigation can be proposed when a mitigation provider believes that the habitat proposed to be used as mitigation will better serve the aquatic resource needs of the watershed/ecoregion. Out-of-kind mitigation often results in a higher mitigation ratio (amount of compensation to impact). Methods- Records from DARTER were used for this analysis (see PRM section of the Methods in the main report). The objective was to find projects that either impacted or provided compensatory mitigation involving seagrass, oysters, tidal flats, and shallow water (Table 1) to determine the proportion of in- and out-of-kind projects. Results- Fifty-eight projects were used for the out-of-kind analysis; among them, 11 projects compensated out-of-kind. The majority of the projects (26 of 58) were from Washington state and consisted of shallow water impacts that were compensated for in- kind. Seagrass impacts were mostly mitigated for in-kind; there was only one project (in California) with seagrass impact that mitigated out-of-kind. The impact was to surf grass [P. torreyi), a type of seagrass that grows in rocky intertidal habitats, and a contribution was made to a local non-profit for kelp (macroalgae) restoration in its place. The 14 other in-kind seagrass mitigation projects were from California, Virginia, Washington, and Florida, with the most being from California and Florida. Oyster compensation occurred equally between in-kind and out-of-kind projects. There were three out-of-kind projects that took place in Virginia. In one project, tidal flat and shallow water were impacted to stabilize a pier and build a bulkhead at a restaurant, and a contribution was made to a non-profit to buy oyster shell for oyster restoration in return. In another, tidal flat was dredged to build a multi-use facility (a dredged material transfer station and canoe launch). A contribution was made to the same non-profit to buy oyster shell for oyster restoration in return. Finally, an oyster restoration project was permitted as compensatory mitigation for a shipping facility that was building new structures by placing fill in unvegetated intertidal and shallow water areas. The three in-kind projects were from Texas and Florida. There were five projects that impacted tidal flats and compensated out-of-kind compared to three that mitigated in-kind. One Texas project was permitted to impact sand tidal flats to build a residential development and coastal prairie pothole construction was approved as compensatory mitigation; another Texas project impacted tidal flats to build a recreation 10 33 CFR 332.3(e) / 40 CFR 230.93(e) 56 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 center and approved creation of a lagoon as mitigation. Of two Florida projects that impacted tidal flats, one restored salt marsh and installed stormwater filtration systems, and the other planted mangroves as compensation. In Virginia, a project that dredged a mudflatto build a multi-use facility (mentioned above) purchased shell for oyster restoration as compensatory mitigation. The three in-kind projects were from Washington and California. There were six out-of-kind projects that involved shallow water compared to 30 in-kind projects. In Texas, two permits were issued for fill of shallow water areas, for modification of a shipping channel and construction of a shipping facility, and salt marsh was created to compensate for each one. A third Texas project used shallow water to compensate for an out-of-kind impact; a tidal flat was impacted to build a recreation center, and mitigation was creating a lagoon (mentioned above). In Virginia, there were three projects that impacted shallow water and compensated out-of-kind (two have already been mentioned above). The third permit impacted tidal flat and shallow water by placing fill for a bulkhead. The permittee was approved to create on-site salt marsh as mitigation. In-kind compensatory mitigation projects came from Florida, California, and Washington. Discussion- The ratio of in-kind to out-of-kind compensation observed was roughly 4:1, but this figure is based on limited data. These examples can inform mitigation work and policy but do not completely represent the amount of out-of-kind compensatory mitigation occurring in seagrass, oyster, tidal flat and shallow water areas nationwide. Other examples of out-of-kind projects that involve these habitats exist. For instance, a recently permitted (2020) large infrastructure project in Maryland is impacting wetlands but is compensating via oyster restoration. Another Maryland project where streams were impacted used estuarine shallow water mitigation (removal of crab pot debris) as compensation. The most instances of out-of-kind projects in the dataset came from oyster and tidal flat habitats. Oysters may be used as out-of-kind mitigation because they are a popular form of restoration that receives public support. For many projects, it was difficult to understand from the documentation available which habitats were impacted and which habitats were used as mitigation. If it was not possible to tell, the projects were excluded from this analysis. In some projects, a matrix of different habitats was impacted, and a matrix of different habitats was used as compensation. Project documentation did not always make it clear which mitigation habitat was intended to compensate for which impact habitat (i.e., in- or out-of-kind), and thus those projects were also excluded. Finally, there were situations where the impact or mitigation habitats were simply not described. For instance, permit documentation for a bulkhead build does not typically describe the habitat it is impacting, even though it could be a subaqueous area, tidal flat, intertidal area, etc. There were also several projects that withdrew credits from a PRM site that was functioning as a bank, but because information about the PRM site was not within the permit documentation, there was no way of knowing what habitats were present at the site. This was the case with four permitted projects in Florida with seagrass impacts; all withdrew credits from two different PRM sites, but those projects could not be included in this analysis. 57 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 The reasoning for using out-of-kind mitigation should be clearly explained in the Memorandum for the Record (MFR) for PRM projects, along with a description of which habitat is being exchanged for which habitat. For this research, the most important document to obtain was the MFR, which described both impact and mitigation, and that anyone undertaking this type of research in the future should request these documents. Table 1- In-kind and out-of-kind mitigation Reference State In kind/ out- DA# Impact Mitigation # of-kind habitat habitat 1 CA In kind SPN-2016-00053 Shallow water Shallow water 2 CA In kind SPL-2010-00028 Shallow water Shallow water 3 CA In kind SPL-2010-01129 Seagrass Seagrass 4 CA In kind SPL-2011-00463 Seagrass Seagrass 5 CA In kind SPL-2012-00172 Tidal flat Tidal flat 6 CA In kind SPL-2013-00146 Seagrass Seagrass 7 CA In kind SPL-2015-00569 Seagrass Seagrass 8 CA In kind SPL-2015-00651 Seagrass Seagrass 9 CA Out-of-kind SPL-2011-00333 Seagrass Macroalgae- kelp 10 FL In kind SAJ-1999-03746 Shallow water Shallow water 11 FL In kind SAJ-2004-01945 Seagrass Seagrass 12 FL In kind SAJ-2008-01022 SAV SAV 13 FL In kind SAJ-2008-04801 Oyster, seagrass Oyster, seagrass 14 FL In kind SAJ-2010-00817 Seagrass Seagrass 15 FL In kind SAJ-2013-00319 Oyster, shallow water Oyster, shallow water 16 FL In kind SAJ-2014-02406 Seagrass Seagrass 17 FL In kind SAJ-2014-03521 Seagrass Seagrass 18 FL Out-of-kind SAJ-2017-01640 Tidal flat Mangrove 19 Oyster, salt FL Out-of-kind SAJ-2004-03490 Oyster, tidal flat marsh, stormwater filtration devices 20 TX In kind SWG-2014-00905 Oyster Oyster 21 TX Out-of-kind SWG-2011-00303 Shallow water Salt marsh 22 TX Out-of-kind SWG-2011-00561 Tidal flat Prarie pothole 58 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Reference # State In kind/ out- of-kind DA# Impact habitat Mitigation habitat 23 TX Out-of-kind SWG-2012-00602 Shallow water Salt marsh 24 TX Out-of-kind SWG-2012-00203 Tidal flat Shallow water 25 VA In kind NAO-2 014-00463 Seagrass Seagrass 26 VA In kind NAO-2015-00310 Seagrass Seagrass 27 VA Out-of-kind NAO-1992-02651 T idal flat, shallow water Salt marsh 28 VA Out-of-kind NAO-2001-03946 Tidal flat, shallow water Oyster 29 VA Out-of-kind NAO-2003-01984 Shallow water Oyster 30 VA Out-of-kind NAO-2010-02401 Tidal flat Oyster 31 WA In kind NWS-2 010-00968 Tidal flat Tidal flat 32 WA In kind NWS-2011-00183 Shallow water Shallow water 33 WA In kind NWS-2011-00761 Shallow water Shallow water 34 WA In kind NWS-2 012-00699 Shallow water Shallow water 35 WA In kind NWS-2 012-00759 Shallow water Shallow water 36 WA In kind NWS-2012-01110 Seagrass Seagrass 37 WA In kind NWS-2012-01175 Shallow water Shallow water 38 WA In kind NWS-2013-00171 Shallow water Shallow water 39 WA In kind NWS-2 013-00419 Shallow water Shallow water 40 WA In kind NWS-2013-01124 Shallow water Shallow water 41 WA In kind NWS-2 014-00159 Shallow water Shallow water 42 WA In kind NWS-2 014-00433 Shallow water Shallow water 43 WA In kind NWS-2 014-00804 Shallow water Shallow water 44 WA In kind NWS-2 014-00890 Shallow water Shallow water 45 WA In kind NWS-2 014-01177 Shallow water Shallow water 46 WA In kind NWS-2015-00291 Shallow water Shallow water 59 ------- Compensatory Mitigation in Estuarine and Marine Habitats February 2023 Reference # State In kind/ out- of-kind DA# Impact habitat Mitigation habitat 47 WA In kind NWS-2015-00601 Shallow water Shallow water 48 WA In kind NWS-2 015-00696 Shallow water Shallow water 49 WA In kind NWS-2 015-00971 Shallow water Shallow water 50 WA In kind NWS-2 016-00200 Shallow water Shallow water 51 WA In kind NWS-2 016-00320 Shallow water Shallow water 52 WA In kind NWS-2 016-00324 Shallow water Shallow water 53 WA In kind NWS-2 016-00902 Shallow water Shallow water 54 WA In kind NWS-2 017-00809 Shallow water Shallow water 55 WA In kind NWS-2012-01111 Shallow water Shallow water 56 WA In kind NWS-2013-00213 Shallow water Shallow water 57 WA In kind NWS-2 013-00245 Shallow water Shallow water 58 WA In kind NWS-2 014-00736 Shallow water Shallow water 60 ------- |