Given the fragmented political jurisdictions, and substantive environmental damages from petroleum spillage, human development and other anthropogenic perturbations, a need exists for developing a coordinated set of protocols and approaches for determining impacts to activities exerting extra-territorial environmental and ecological pressures on coastal and offshore natural resources in the ROPME Sea Area (RSA; also known as the Gulf), as well as strategies for restoring (or mitigating) natural resources by human activities. Such environmental impact assessment and natural resource damage assessment protocols may readily be developed at the ecosystem level to directly inform localized coastal and marine resource decision-making by resource managers with harmonization to the Gulf level. Instead of traditional methods for gauging environmental impacts (or damages) on a single resource or habitat, impacts of anthropogenic activities may be reviewed on an ecosystem level with a focus on services provided by ecosystem components. This way, relative impacts to ecosystem services can be evaluated in order to determine the overall impacts to the system as a whole, rather than simply to a few targeted resources that exclude critical ecosystem components, functions and services. Examples of such methodologies are discussed in the context of international case studies. Considerations, limitations and strategies for adopting these ecosystem based approaches are presented.
The ROPME Sea Area, also known as the Gulf, is a semi-enclosed body of water with eight fragmented jurisdictions, each with its own socio-economic and political agenda (Khan et al., 2002). Sectoral management based on sovereign political divisions is a major driver of decisions affecting the Gulf, resulting in little overall regional management at the marine ecosystem and biome level. This results in a lack of integrated environmental management frameworks involving the various sectors of the Gulf (Al-Otaibi, 2002). Accordingly, a need exists for consistent, rigorous and defensible approaches for determining impacts to human activities exerting extra-territorial environmental and ecological pressures on coastal and offshore natural resources in the Gulf, as well as strategies for restoring (or mitigating) injured natural resources. Such environmental impact assessment and natural resource damage assessment (NRDA) protocols may readily be developed at the ecosystem level to directly inform localized coastal and marine resource decision-making by resource managers with harmonization to the Gulf regional level. Instead of traditional methods for gauging environmental impacts (or damages) on a single resource or habitat, impacts of anthropogenic activities may be reviewed on an ecosystem level with a focus on services provided by ecosystem components. This way, relative impacts to ecosystem services can be evaluated in order to determine the overall impacts to the system. This paper describes a series of practical ecosystem level management tools, including oil spill (impact) modeling, Habitat Equivalency Analysis (HEA) and Quantitative Mitigation Analysis (QMA), in the context of international case studies. Considerations, limitations and strategies for adopting these ecosystem based approaches within the Gulf are presented to illustrate the functionality of these ecosystem tools.
A number of tools exist which used alone or in combination, provide a robust analysis of either retrospective or prospective impacts stemming from various anthropogenic perturbations. Retrospectively, impacts to natural resources resulting from oil or hazardous substance releases (i.e. spills) may be determined and quantified using spill impact modeling packages such as SIMAP (French McCay and Rines, 1997; French McCay, 2003, 2004, 2009). Further, once injuries resulting from spills and spill response operations to natural resources (i.e. flora and fauna) are quantified using modeling procedures during a natural resource damage assessment (NRDA), tools are available to scale (or size) the appropriate amount of compensable projects necessary to restore losses and accelerate recovery of injured resources (i.e. restoration projects). One notable restoration project scaling tool is Habitat Equivalency Analysis (NOAA, 1995; French McCay and Rowe, 2003).
Prospectively, habitats and corresponding natural resources are either directly or indirectly injured as a result of coastal, near shore and offshore development (e.g. stemming from waterfront construction, pier structures and offshore oil platforms or wind farms), resulting in quantifiable environmental impacts to the coastal and marine environment. While industrial facilities may be a future source of oil and chemical releases, most all development results in some habitat degradation. Accordingly, spill impact modeling may be used as a planning tool in industrial site selection or for spill contingency planning purposes. Tools such as Quantitative Mitigation Analysis (Reilly and Grant, 2007) have been developed which quantify habitat losses resulting from human development, and, moreover, are used to calculate the amount of compensatory mitigation project(s) necessary to compensate the public for losses resulting from planned development activities. Chemical and oil spill modeling, Habitat Equivalency Analysis and Quantitative Mitigation Analysis tools are described in more detail below.
Oil and Chemical Spill Modeling
Computer models such as OILMAP and SIMAP have been developed to inform spill trajectory and impact modeling, respectively. More specifically, OILMAP provides rapid predictions of the movement of spilled oil (ASA 2007). OILMAP is an oil spill model system designed for oil spill response and contingency planning. It includes simple graphical procedures for entering spill information and connects to on-line weather forecast servers for accurate wind and current data. OILMAP uses a variety of electronic chart systems, including global nautical CMAP charts from Jeppesen Marine and is also compatible with ESRI GIS software. OILMAP's ability to rapidly provide oil spill trajectory predictions anywhere in the world makes it well suited for spill contingency planning and informing environmental management decision-making actions (ASA, 2007).
SIMAP is a personal computer-based modeling software application which estimates physical fates and biological effects of releases of oil and petroleum products. Both the physical fates and biological effects models are three-dimensional. Quick trajectories and screening scenarios are implemented through a two-dimensional oil spill model. The models are coupled to a geographic information system (GIS) which contains environmental and biological data, and also to physical-chemical properties and biological databases containing necessary input for the models. Both SIMAP and OILMAP have been effectively used in numerous applications throughout the Gulf in a range of oil fate and effects applications.
Environmental impacts associated with oil and chemical spills may be assessed retrospectively (i.e. post-spill) or prospectively (i.e. in a contingency planning mode) using the biological effects model in SIMAP. This model estimates short term (acute) exposure of biota of various behavior types to floating oil and subsurface contamination (in water and subtidal sediments), resulting in percent mortality, and sublethal effects on production (growth). Mortality for each wildlife (bird, mammal, and reptile) behaviour group is based on the area swept by surface oil over a threshold thickness that would affect an animal with a lethal dose, the probability of encounter with the oil on the water surface, and the probability of mortality once oiled. Toxicity to aquatic biota in the water and subtidal sediments is estimated from dissolved aromatic concentrations and exposure duration, using laboratory-based bioassay data for oil hydrocarbon mixtures (French McCay, 2002).
Prospective and retrospective impacts are quantitatively estimated by species or species group for wildlife, fish, and invertebrates by multiplying areas or volumes at various percentage losses by the density of animals per unit area or volume. However, equivalent areas or volumes of 100% loss (the weighted sum of lesser percentage losses) may be compared to estimate relative impacts to wildlife versus fish and invertebrates for spill response purposes, as well as in ecological risk assessments. The use of equivalent areas and volumes for 100% mortality as metrics is an innovative approach that allows quantitative comparisons to be made between impacts to surface-related and water column-related resources, without having to estimate species densities. Since densities of all biota are highly variable in time and space, in some cases potential end-users of the model results have difficulty accepting the assumed biological data used as a model input. This approach avoids that controversy, and better allows issues to be addressed, such as the evaluation of trade-offs in dispersant use between impacts to wildlife and water column biota in determining the best course of action to minimize overall impacts to biological resources.
Habitat Equivalency Analysis (HEA)
Damages to coastal habitats can occur from oil spills, hazardous substance releases, vessel groundings, or other damaging actions (Figure 1). The damages cause a disruption to the services provided by the habitat until the habitat is able to recover to pre-disturbance conditions. Government Authorities, acting on behalf of the public, may seek to recover the damages to facilitate recovery of the injured area (primary restoration) and to compensate for the interim loss of services occurring prior to full recovery (compensatory restoration) (NOAA, 2011). HEA was used by the United Nations Compensation Commission (UNCC) in the evaluation of restoration requirements to compensate for injuries sustained as a result of the 1990–1991 Gulf War.
Habitat Equivalency Analysis (HEA) is an analytical framework developed to calculate compensation for loss of ecological services resulting from injury to a natural resource over a specific interval of time (King and Adler 1991; NOAA 1995). Figure 1 provides a graphic representation of the relationship between the interim loss from an environmental incident or activity and the recovery of the environment over time due to natural mechanisms and any primary restoration actions. The HEA approach focuses on scaling replacement costs on a service-to-service basis. Therefore, in quantitative expressions HEA relies on biophysical units such as hectares of habitat as a surrogate of service, and calculates the increase in habitat over time in service hectare years. A similar methodology, Resource Equivalency Analysis (REA) focuses on scaling replacement costs on a resource-to-resource approach. In this context, resources are generally defined in terms of biotic type and mass (e.g. kilograms of fish) for the quantification of injury, but often ultimately revert back to an estimate of habitat required to replace or generate those lost resources in estimating the size and type of replacement actions required to restore the environment.
An excellent software package, Visual HEA, developed by the National Coral Reef Institute at Nova Southeastern University, may be used to calculate habitat equivalency on a personal computer (Kohler and Dodge, 2006). Visual_HEA is a program that provides an efficient method of calculating the required compensation.
Quantitative Mitigation Analysis (QMA)
Quantitative Mitigation Analysis (QMA) is a methodology developed to assist governmental permitting authorities with developing defensible, quantitatively-based compensatory mitigation requirements for, especially, large and/or complex property developments/betterments that result in a taking of, or diminution of quality to, natural resources under their jurisdiction (Reilly and Grant, 2007). QMA calculates the loss of ecological and/or public use services related to the nature, degree and spatial/temporal extent of lost natural resources resulting from a development using modified natural resource damage assessment methodologies. Further, QMA is used to evaluate proposed project(s) ability to compensate for discovered injuries, or identify alternative or additional projects to appropriately compensate for lost services. The cost of compensatory mitigation required of a developer is the cost of project(s) required to provide an equivalent nature, type and degree of ecological and/or public use services which were directly or indirectly lost by a development to the extent practicable. QMA was developed to address an observed need by permitting authorities to have a rigorous, defensible and repeatable approach to deriving an appropriate level of compensatory mitigation to require from development project proponents. A defensible and quantitative approach to deriving level/amount of compensatory mitigation protects both the public and development/industrial sectors by defensibly deriving quantitative compensatory mitigation requirements. Due to similarities in approach, HEA and REA procedures described above may be adapted for use in QMA compensatory mitigation determination and quantification actions.
Example applications of spill impact modeling and HEA in Florida, USA, trajectory modeling in Dubai, and QMA in Massachusetts, USA are presented below to illustrate the functionality of these ecosystem tools.
Use of SIMAP and HEA to Assess Injuries and Scale Restoration Following a Mystery Spill in Florida, USA
On August 8, 2000, oil tar balls and oil mats were observed on beaches in the area of Fort Lauderdale, Florida from an unknown source. Within the next few days, approximately 32 km of high-use recreational beaches, from North Miami Beach northward to near Pompano Beach (primarily Broward County beaches), were oiled and required shoreline treatment. The oil spill incident most likely occurred from a ship traveling northward in the western edge of the Gulf Stream the previous evening. Natural resource injuries to birds, turtles, fish and shellfish were determined and quantified by state and federal government trustees using spill impact modeling; and public beach use loss was extrapolated from information gathered about baseline beach use. Restoration projects were based on the type and scale of these modeled and extrapolated injuries (NOAA and FDEP, 2002; Boltin and Reilly, 2005).
Use of SIMAP as a Forensic Tool to Inform NRDA
In order to develop the Fort Lauderdale Mystery Spill (FLMS) natural resource damage (NRD) claim for submission to the United States Coast Guard (USCG) for payment of assessment and restoration costs, the NRD claimants (National Oceanic and Atmospheric Administration [NOAA], and Florida Department of Environmental Protection [FDEP]) were required to not only conduct normal NRDA activities (i.e. injury assessment and restoration plan development), but also address the suite of unknowns surrounding this mystery spill, which are central to the conduct of a defensible injury assessment (e.g. defining spill scenario, source oil composition and toxicity, etc.).
Spill Scenario Development
Using oil spill (SIMAP) modeling and local shipping traffic practices as forensic tools to help address these issues, the trustees concluded that the oil was likely discharged from an area near the western edge of the Gulf Stream sometime during darkness the evening or morning prior to it being reported on the beach on 8 August, 2000. This is based on: the backtracking of the oil from the oiled beaches using SIMAP modeled spill hindcasting techniques; the likelihood that the spiller would have released the oil after dark on 7 August (since it was not reported as seen until morning on 8 August); and the practice of northbound ship traffic traveling in the Gulf Stream (French McCay et al., 2001).
The monoaromatic oil components (benzenes, xylenes and toluenes also known as BTEX) were not measured in the source oil for either FLMS or the PEPCO spill, but are assumed to have negligible impact on water column organisms because of its high volatility (French McCay et al., 2001). The oil volume that came ashore was estimated by Zengel (2000) to be approximately 56,800 l based on observations of amount of oil on each beach segment. Zengel's estimates were corrected for the volatile and semi-volatile content (3.3% PAH + 23.4% other volatile hydrocarbons), resulting in a volume estimate of 77,400 l. Assuming the Gulf Stream velocity estimated by NOAA NRDA personnel on scene during the clean-up and using wind data for the days preceding the oil stranding, the discharge location was likely southeast of the most heavily oiled beaches. The oil likely crossed the west edge of the Gulf Stream at midnight, and then came ashore between 0800 and noon on 8 August. Thus, the spill likely occurred between 1900 and 2300 on 7 August. This range of spill times was run with the model to determine the sensitivity of the injury results to the assumed spill time. The spill was assumed to occur continuously over 1 hour along a straight track line (French McCay et al., 2001).
Fort Lauderdale Mystery Spill NRD Claim
The government trustees determined and quantified injuries in four main categories: (1) recreational beaches, (2) sea turtles, (3) water column injuries to fish and invertebrates, and (4) seabirds. Based on this work, the trustees claimed that the mystery spill incident caused the loss of public beach use and significantly injured sea turtles, fish and invertebrates, and seabirds. The trustees used restoration costs as the measure of damages for injuries to the ecological resources (i.e. “service-to-service” scaling approach). These costs include the costs to design, permit, construct, and monitor the restoration projects. Loss of public use injuries are outside the scope of the present study. For biological injuries, a listing of determined injuries and proposed restoration projects, including respective costs, to compensate for these injuries is provided in Table 1.
Aquatic Biological Resource Restoration Selection and Scaling
To compensate for losses of fish and shellfish from the spill, as determined through SIMAP modeling, mangrove restoration at Virginia Key, just south of the spill impact area was selected. The area of restoration on Virginia Key is situated between the water treatment facility and the west shoreline of the Key where there are over seven hectares available for restoration. The elevation of the area ranges from 0.3 m to 2.4 m above the mean high tide mark with exotics invading 30% to 65% of any given area. To enable successful mangrove restoration, some areas would have to be scraped down, exotics would have to be removed, and mangroves would have to be planted (NOAA and FDEP, 2002).
The Trustees used a service-to-service HEA scaling approach to determine the mangrove compensatory restoration project scale. The size of the mangrove habitat project is selected so that the biomass of fish and invertebrates provided by the habitat is equivalent to the biomass that was lost due to the injury. The mangrove project has to provide 10,930 kg of fish and invertebrate biomass in order to compensate for the loss based on quantified fish and invertebrate losses using SIMAP modeling. To be able to determine restoration scale, the Trustees had to identify a number of parameters that characterize mangrove restoration. A study of mangrove habitats from the southern Gulf of Mexico calculated that 12 g of fish and invertebrates are produced per square meter of mangrove habitat per year (Yanez-Arancibia et al., 1980). Because created mangroves do not provide full services immediately after construction and they may not function as well as natural mangroves, the Trustees have to adjust the annual estimate of production over time. Michel (J. Michel, Research Planning Inc., Columbia, SC., submitted, 2001) conducted a review of the literature on mangrove function; she found little published data on fishery habitat value and services of restored mangroves. One study that evaluated four mangrove sites indicated that comparable fish communities were established in three to five years. In another study, fish and shrimp density in a replanted mangrove was as high as that of natural mangroves after five years. The Trustees determined that a created mangrove would mature, linearly, over five years and achieve the productivity of 12.0 g per m2 per y based on a literature review of productivity rates. The created mangrove is expected to support fish productivity for 50 years. Michel investigated the longevity of mangroves and found that some stands have survived for 70 years or more; however, mitigating this longevity are changing environmental conditions including hurricanes and tropical storms, which are common in South Florida. These parameters determine the biomass produced over the course of the mangrove's expected lifetime. These data are used in HEA restoration scaling calculations to demonstrate that one hectare of mangrove produces a discounted biomass of 2,696 kg (using a three percent discount rate). In order to provide the biomass that was lost, the constructed mangrove has to be four hectares (10,930/2,696).
Use of Oil Spill Modeling to Inform Environmental Management Decision-Making
Oil spill modeling may be used to inform contingency planning decisions regarding future spill impacts, facilitating strategic decision-making regarding facility siting and measures to be taken in the event of an actual oil spill. For example, OILMAP Software (by Applied Science Associates [ASA], 2007) was used to predict oil spill movement from likely spills off the shore of Dubai for Dubai Petroleum Company (DPC) (Applied Science Associates, 1998). Oil spill trajectory and fates analyses were undertaken to address the consequences of a “worst case” oil spill on the continued operation of Dubai's seawater desalination capacity. Two spill events (the Akari in 1987 and the Ajman spill in 1998) were reviewed in some detail through a “hindcast” study. Good correspondence was demonstrated between observations taken at the time of these spills and the predictions from ASA oil spill models for both events (Howlett et al., 2008). Sea surface predictions of oil movement were extended to subsurface hydrocarbon concentration analyses to show what oil entrained into the water column and floating on the sea surface might be entrained by the existing sea water intakes at the existing nearby steam power station intakes.
Analyses developed and used in a previous study for 54 seawater intakes in Saudi Arabia were applied to both the existing intakes and to proposed offshore extensions (Figure 2). These analyses demonstrated that:
The existing intake structures are vulnerable to future spill events; (2) a very large and uncontrolled spill event might cause observed hydrocarbon levels in the existing intakes to exceed operational levels for safe desalination plant operation; and (3) modifications to the existing intakes to either move some intakes offshore or to construct alternative desalination/power generation facilities at the far end of the Dubai coastline would make it possible for at least partial desalination production to continue through any foreseeable event. Follow-on work involved stochastic simulations of very large offshore oil spills and the probable fate of the spilled oil.
Quantitative Mitigation Analysis (QMA)
In order to quantify coastal and offshore habitat-specific compensatory mitigation requirements, Quantitative Mitigation Analysis (QMA) may be used.
A QMA analysis allows a developer to explicitly address how interim habitat (i.e. benthic habitat and (any) resource losses are to be addressed through compensatory mitigation projects to make the public whole for such losses. An appropriate level of compensatory mitigation to mitigate for these losses should be addressed as part of a holistic compensatory mitigation package (Reilly, 2009). QMA may be very useful in the rapidly developing coastal zone of the Gulf Region to quantify compensatory mitigation requirements.
For example, a large, offshore wind farm is proposed for Nantucket Sound off of Massachusetts, USA. This offshore electrical power production facility will involve the taking of benthic and intertidal habitat due to the construction and deployment of offshore (monopile-type) wind towers and associated equipment. QMA was used to calculate the habitat-specific loss for this development as part of the responses to the offshore permit application by the system developer (Reilly, 2009).
Specifically, the Final Environmental Impact Statement (FEIS) stated that, “Construction and operation of the proposed [wind farm] action would result in an irreversible or irretrievable loss of some biological resources, including the irretrievable loss of approximately 45,134 m2 of soft bottom habitat due to the Electrical Service Platform (ESP) and monopiles 2,727 m2, scour mats 7,946 m2, and rock armor 35,417 m2.” It should be noted that this does not necessarily include the several kilometer long transmission cables from the offshore facility to landfall. However, this stated irretrievable loss of important soft bottom habitat the FEIS provided no clear compensatory mitigation for shorter and longer term “takings” of benthic unconsolidated mud and sand marine habitat. The proposed project shall result in the takings of benthic habitat during all phases of the facility: construction, operations and maintenance and decommissioning.
Accordingly, a QMA approach was used to calculate projected losses to benthic habitat as a result of the proposed development. Table Two (2) provides a summary of these findings. Annualized data results from these habitat loss projections were derived based on construction, operations and decommissioning actions described by the proponent. From this analysis, it is estimated that over approximately 400,000 square meter–years of habitat services are projected to be lost from this project. This estimate is conservative as it does not consider losses due to installation of the inner array cables. The projected benthic habitat losses described in Table Two (2) illustrate the significance in magnitude of potential interim resource losses associated with the proposed offshore power plant in Nantucket Sound.
Anthropogenic impacts to the coastal and marine environment, including oil and hazardous substance spills, sedimentation and on/offshore developments, are inherently difficult to assess with respects to connecting a particular perturbation to a set of manifest effects (injury determination) and quantifying the magnitude of injury (injury quantification). Injury determination and quantification are challenges due to a range of factors, not least is the inherent variability in population size and health, resulting in oft weak signal (impact) to noise (natural variability) ratios. Further, once (prospective or retrospective) injuries to natural resources are determined and quantified, sizing-scaling–the magnitude of restoration or compensatory mitigation projects to offset these impacts is complex: what is the basis for sizing projects–population numbers, species, or some other parameter? Within the Gulf, this is compounded by the fragmented political landscape, transboundary movements of pollutants, and an array of national and international laws, conventions and agreements governing environmental impact assessment and natural resource damage assessments. The tools presented here, oil spill (impact) modeling, Habitat Equivalency Analysis (HEA) and Quantitative Mitigation Analysis (QMA), provide a rigorous means for the conduct of past (retrospective) and future (prospective) impact assessment and restoration or compensatory mitigation project planning. These tools are based on the services provided by species residents of coastal/marine ecosystems. The value of using services provided by species–rather than species per se–is that ecosystems can be managed by the ecological services they provide; hence, exchanges can be made between impacted ecosystem residents. This significantly increases the potential and scope of useful restoration or compensatory mitigation project planning–i.e. it is often not feasible to restore a lost organism/species at the location of the loss; however, it may be possible to restore the services lost to the ecosystem for the interim period of loss.
With the rate of (1) oil and hazardous material releases; and (2) the unprecedented scale of coastal development in the Gulf-member states, these tools may be very helpful to restoring lost ecosystem services resulting from spills and coastal development. Further, these tools are well developed, offering a defensible and consistent approach to these issues. The importance of consistency and technical rigor within the coastal/offshore permitting, mitigation and spill impact assessment and restoration processes cannot be understated. Frequently, impact assessments, due to their complexity (signal to noise ratio) and cost to implement, are non-conclusive and not comprehensive in scope. Further, restoration and compensatory mitigation project planning is a relatively new field, often resulting in reliance on project scaling through negotiations, rather than on a fact-based set of quantitative principals. These issues are directly addressed with spill modeling, HEA and QMA protocols and procedures.
It is important to note that these ecosystem-based tools are reliant on good data inputs. These data, e.g. for modeling: conditions/location of spill, chemical characteristics of spilled material, affecting currents (hydrodynamics) and wind regimes, are critical to yielding reasoned and defensible results. Further, collection and chemical analyses (fingerprinting) of source oil, tissue, sediment and water samples, coupled with oil trajectory/transport real-world observations on water and land is needed to inform and validate modeling results. With regards to HEA and QMA, a defensible level of injury, timeframes of injury (and restoration/mitigation projects) and support for service losses corresponding to injuries endured are important factors in scaling appropriate projects within the Gulf.
During interpretation of spill modeling, HEA and QMA results, it is important that expertise is leveraged to ensure appropriate and reasonable conclusions are drawn from injury assessment and project scaling results. Accordingly, it is suggested that a center of excellence for natural resource damage assessment and environmental impact assessment be established to address these challenges within the Gulf region (e.g. at ROPME or MEMAC). This center would address the spectrum of NRDA and EIA issues, providing targeted expertise to ROPME member states. Further the center would leverage the substantial amounts of information gained by Gulf States from NRDA's conducted following the Gulf War, as well as building on local/regional processes and protocols developed for ongoing environmental impact assessments in the Gulf.
In conclusion, it is observed that oil spill (impact) modeling (e.g. using SIMAP and OILMAP modeling software), Habitat Equivalency Analysis and Quantitative Mitigation Analysis offer useful tools for assessing retrospective and/or prospective impacts to the coastal and marine environments from oil and hazardous substance spills and coastal/offshore development, facilitating the determination and quantification of manifest impacts to natural resources, as well as scaling the appropriate type and size of restoration or compensatory mitigation projects. These tools are well suited for the complex ROPME Sea Area's biological, physical and political environments. A center of excellence addressing NRDA and EIA may be warranted to provide target expertise in the development and implementation of these unique programs for Gulf member states.
The authors wish to thank the Kuwait Institute of Scientific Research (KISR) for its kind involvement and support of cooperative natural resource damage assessment and environmental impact assessment initiatives.