A field guide to oil spill response on freshwater shorelines: chapter 5

5.1 Net environmental benefit analysis

During an oil spill response, a key objective is to minimize any effects on resources at risk – resources may be ecological, socio-economic, or cultural/historical. Net Environmental Benefit Analysis (NEBA) is a process used by both contingency planners and incident managers to aid in decision-making on the best response tools to use, allowing comparison of different tools, as well as the consideration of any ecological damage that might be caused by the treatment methods available (IPIECA-IOGP 2015).

NEBA is a structured approach allowing for the comparison of the advantages and disadvantages of each response tool, including allowing the oil to naturally attenuate, to limit overall ecological, socioeconomic and cultural effects. The decision-making process must also involve consideration of and compliance with government regulations. Often the best approach might be to allow the affected resource to recover naturally without any treatment, especially where the damage was light or where the available treatment options might cause more harm than the oil itself.

A NEBA for response tool selection is carried out using four steps:

1. Compile and evaluate data: During this first step the important resources that could be affected by the oil spill are identified and prioritized for protection based on environmental sensitivities and social values.
2. Predict outcomes: The oil spill planning scenarios are then used to assess potential effects and response options for specific plants and animals, habitats, and other resources that have been identified as important. Fate and trajectory model inputs (from OILMAP, OSCAR, or GNOME/ADIOS 2) are used for various spill scenarios.
3. Consider trade-offs: The potential environmental and social effects are then weighed against one another to determine the most effective oil spill response tools and balance trade-offs. The trade-off for each segment or section of shoreline typically considers: the predicted fate and persistence of the residual oil; the estimated rate of natural recovery (time element); the possible benefits of a treatment in terms of accelerating recovery; the risks associated with the presence of the oil as it weathers; and the possible delays to recovery that may be caused by response activities. An important component of this process is the methodology used for the risk assessment to determine the net environmental benefit of a response tool (Table 5.1).
4. Select best options: Each response tool will have different effects on the variety of resources also affected by the oil spill (e.g. shorelines, waterfowl, fisheries, marinas). Local stakeholders and response partners work together to choose the best tools (or combination of tools) available to minimize the effect on the environment and the community. The optimal treatment technique would: have a minimal effect on the affected resources (i.e. the benefits outweigh the effects of the response technique); involve minimal labour and logistical requirements; provide rapid treatment rates; and generate no/minimal oiled waste.

Multiple stakeholders are involved in the NEBA process, which relies on cooperation among various levels of government, industry and communities to ensure that informed response decisions can be made which take all perspectives and viewpoints into account. Response options should be reviewed and fine-tuned throughout the response as information about the distribution and degree of oiling is updated.

NEBA may be used during pre-spill planning and during an oil spill response:

• NEBA is an important part of the pre-spill planning process and is used to ensure that all potential stakeholders and response partners are engaged and response options for different planning scenarios are well thought out.
• During a response, the process is used to ensure that evolving conditions are understood so that the response options can be adjusted as needed.

The process conducted during an oil spill is the same as that conducted during pre-spill planning, however:

• There is only one spill scenario to address during an actual spill and known spill conditions mean some uncertainties are reduced (e.g. the type and amount of oil released is typically known).
• Decisions need to be made quickly and data may be incomplete. Decisions may rely more heavily on expert opinion and professional judgment in comparison to pre-spill planning.
• Delays in decision-making may limit the feasibility of a response tool during an oil spill (e.g. the ‘window of opportunity’ may close).
• Specifics of the actual oil spill may change previously agreed to priorities for protection or acceptable trade-offs, so these will need to be revisited on an ongoing basis for the duration of spill response.

The NEBA process can also be used to help make decisions concerning restoration activities that may be planned and undertaken after an oil spill response.

5.2 Shoreline response programs

There exist clear differences between the scope of response plans for spills to small creeks and streams, rivers, and lake or marine coasts (Figure 5.1). The primary difference is that the planning for spills into ditches, creeks and streams can be quite site-specific and focus on identifiable potential risks and effects, more so than river, coastal, or open lake and marine spills as forecasting of spill movements are typically more accurate. From a response standpoint, the consequences as oil transitions from the creeks and streams, to rivers, and then open lake and marine coasts are that the scale of the survey strategy and the size of response area increase with the spreading of the oil.

Figure 5.1: Time-space schematic for spills in different environments (from Owens 2017)

The scale of the response has a direct effect on shoreline response planning in terms of the span of control and the size of the SCAT program. The size of affected area for a spill into a stream or creek may be on the order of a few hundreds of metres to tens of kilometres, whereas oil that reaches a large river channel or an open lake shoreline can affect tens to hundreds of kilometres. The issue is compounded in rivers by the potential for oiling on both banks and on mid-channel islands or bars.

A Shoreline Response Plan (SRP) is intended to integrate all aspects of a response from the initial oiling assessment, SCAT field surveys, operational activities to treat or remove stranded oil, through to the inspection process that provides closure to the response. An SRP is established as soon as it is evident that lake shores or river banks have been oiled or potentially would be oiled. A SCAT program is a key component of an SRP that provides data on the oiling conditions, recommendations for treatment activities and a mechanism to determine that treatment criteria have been achieved (ECCC 2018). Refer to Section 8.1 for additional discussion of shoreline treatment criteria.

The primary functions of an SRP are to:

• Focus on the shoreline component of a response
• Maintain span of control
• Develop long-term strategies
• Initiate, implement and manage a SCAT program within the SRP
• Provide survey data to the spill management team decision makers
• Coordinate between the decision makers, the command staff, planning and environmental managers and Operations to generate, implement and manage the SRP
• Incorporate Shoreline Treatment Recommendations (STRs), which are generated by the SCAT teams and approved by the command staff, into the SRP
• Liaise with Operations in the Command Post and in the field to ensure that the SRP and the STRs are understood and implemented appropriately
• Develop and test new or improvised treatment tactics
• Track STRs and operational progress
• Manage segment inspections and treatment completion determinations (removal of signed off/approved segments from the response)

An SRP integrates the various aspects of a treatment program such as the field SCAT surveys, data management, the treatment decision process, generation of treatment recommendations, operations support and liaison, and post-treatment inspections (ECCC 2018).

Key components of an SRP include:

• Health and safety
• Program objectives
• Program management
• Field team participants
• Field methods and forms (aerial reconnaissance during initial stages; shoreline inspections)
• Shoreline treatment process
• Data management and reporting
• Logistics
• Spill management support
• Liaison with the Operations Section
• Treatment criteria
• Shoreline treatment options
• Prioritization of treatment by segments
• The sign-off and completion process

5.3 Segmentation and mapping

Segmentation is the backbone of a SCAT mapping and data framework. All information collected, whether for pre-SCAT, or during SCAT surveys, monitoring, or inspection surveys are managed and processed within this framework. Each segment (or sub-segment) has a set of criteria and conditions (treatment criteria, priorities, tactics and constraints) that are used by Planning and Operations throughout a response.

Shoreline segmentation, wherever possible and appropriate, should consider the parameters described in the following sections.

5.3.1 Lakes

Lake shoreline character

The primary rationale for shoreline segmentation is based on the division of along-shore sections within which the shoreline character is relatively homogeneous in terms of physical features, sediment type, vegetation cover, and wave exposure, as they relate directly to oil behaviour and treatment options (Figure 5.2). Treatment approaches for different types of shoreline substrates are provided in Section 6.3.

Figure 5.2: An example of primary segmentation for shoreline

Backshore character

The backshore character and land use are frequently important for response decisions as well as logistics. Changes in the backshore can be an important consideration in segmentation as they may affect access, staging and treatment options; i.e. is the backshore character a cliff, forested lowland, wetland, agricultural field, public park, or parking lot?

Jurisdiction

Segments that span jurisdictional boundaries often can necessitate the inclusion of multiple stakeholders and Indigenous communities with different objectives and concerns that could be avoided if segments or sub-segments are delineated according to these boundaries. These boundaries can be administrative, political or related to land ownership or management.

Rivers and streams at the shoreline

A guiding principle for segmentation along a lake shoreline is to avoid the use of a river and stream for segment breaks. Rivers and streams often have fisheries or other wildlife concerns and a segment break in the channel places all related restrictions into two separate segments when those may apply equally to both banks of the channel. It is preferable to make the stream or river channel and the adjacent shoreline a single unit so that the segment has its own physical and ecological identity (Figure 5.3).

Figure 5.3: Segmentation at rivers and streams

Lake shoreline segmentation naming convention

In order to provide shoreline segmentation that can be used by all response personnel, a segment naming convention must be systematic, easy to adapt, and intuitive to use. On small local spills with only a few segments, this can be a simple sequence of numbers, i.e. 1-10. On larger spills with more extended coverage, segments are broken into operational groups, i.e. ABC-01 to ABC-10. Segmentation may have to include regional as well as local geographic naming to provide a unique reference name to all shorelines within response plans.

A hierarchical structure, starting at the highest level and subsequently broken into smaller sections down to the individual shoreline segments or sub-segments, provides a method to collect and manage data at different levels of detail (geographic scale) within the same segmentation framework. Each segment or sub-segment would have a unique reference name within the hierarchy, no matter how large the response area (Table 5.2).

The higher levels in the hierarchy (1-3) provide a Geopolitical Reference (ON/HUR/NTW), and the lower levels (4-6) define the individual sections of shoreline or Mapping Units (NWB-01). The resulting hierarchical naming, for example ON/HUR/NTW/NWB-01, would define a section of shoreline at Wasaga, Ontario, in Lake Huron. A Sub-segment identifier (6) can be added if it is important to further define and describe unique features or conditions within a segment.

Minimizing the segment numbering to a small count within local geographic groups is more intuitive for operational segments. Depending on the size and location of a spill, only the last section(s) of the naming reference would be used in a response, i.e. NWB-01.

5.3.2 Rivers

The segmentation process for rivers, streams, and creeks is slightly different as the “shorelines” include the two river/stream banks as well as mid-channel islands or bars. For the purpose of a SCAT survey, a distinction is made between rivers and streams, creeks or ditches based on survey and operational factors:

• Rivers: Surveys and operations are conducted separately for each of the right bank, left bank, and mid-channel island, etc. This typically involves access to the shoreline from different backshore locations or by water.
• Streams, Creeks, and Ditches: A survey or an operations activity may be conducted for both banks at the same time. Access to adjacent banks is the same, typically from the backshore.

River segmentation may differ depending on whether pre-SCAT mapping has been completed and segments pre-identified or if segments are created at the time of a response. In the absence of pre-incident segmentation and mapping the most practical approach is based on fixed-length downstream subdivision for the response area (Section River KP Segments and Sub-Segments). Pre-incident segmentation and mapping does not have a “starting point” and is based on a hierarchy of subdivisions creating unique Segments within a larger mapping framework (Section River Segmentation Naming Convention).

River KP Segments and Sub-Segments

In the absence of segmentation at the time of an incident, the KP (Kilometre Post) Segment and Sub-Segment concept is practical and straightforward for all rivers, streams and creeks. The segmentation system follows a simple downstream fixed-length KP sequence starting at the Point of Entry (POE = KP 00). The fixed lengths follow the midstream of the channel and can be generated by a GIS or by hand on maps:

• For streams and creeks this fixed-length segmentation system typically is sufficient (Figure 5.4).

Figure 5.4: Single-channel stream or creek KP segmentation

• For single channel rivers, with small bars and small islands that may be seasonal in character, the same simple downstream KP segmentation sequence starting at the POE is sufficient with segments based on location within the KP channel section; for example, KP 04, with Right Bank, Middle Channel, and Left Bank (RB, MC, LB) segments facing downstream; e.g. 004-RB, 004-MC, 004-LB.

Even a single channel system may have some complexity if islands are present (Figure 5.5):

• Island banks have a sub-segment alphabetic designation in addition to the segment number, to allow for coding multiple separate islands within a 1 km section of river; e.g. 001a-MC, 001b-MC, etc.
• Where islands cross KP segment boundaries, the section of river that contains the majority of the island bank is used in the naming convention (e.g. 003a-MC).
• Where islands span a longer section of river (> 1 km) the left bank and right bank of the island are given a separate alpha-numeric designation to minimize long segment lengths and simplify SCAT survey logistics (e.g. 004a-MC, 004b-MC).
• Under certain circumstances, subdivision into sub-segments may be appropriate to identify changes in land ownership or management (such, as stakeholder lands, parks or industrial facilities).

Figure 5.5: Single-channel river segmentation with sub-segments

For a multi-channel river, the same KP segmentation approach can be used based on a single major channel, if there are two channels, or the median channel, if there are more than two channels (Figure 5.6). The major or median channel retains the 1-kilometre KP segment numbering system based on starting at the POE with an “A” prefix; for example, A-001. The segmentation within the main channel (A) represents the overall distance (km) downstream from the POE.

• The first diverging, or side, channel is assigned a “B” alphabet prefix based on the KP at the point of divergence (e.g. B-005) and is numbered through to the KP where the channel reconnects the major or median channel (B-045).
• The KP sequence number of the divergent channel may be less or greater than that of the major channel where they reconnect, as is the case for the “B” channel in Figure 5.6.
• The alphabet prefix is then used sequentially downstream with each new divergent channel number beginning at the main (“A”) channel divergent KP; e.g. C-010, which reconnects at C-033.
• This means that all segment numbers, regardless of channel, represent the distance (km) downstream from the POE within each designated channel.
• If a channel diverges from a secondary channel, a system could be developed with a similar numbering concept, for example, BA and BB for channels diverging from the secondary B channel.

Figure 5.6: Multiple-channel river segmentation with one primary (“A”) and multiple secondary channels (“B” and “C”)

This river segmentation concept, whether for single- or multiple-channel systems, is based on fixed distances downstream and runs counter to the standard marine or lake shoreline segmentation process, which is typically based on changes in substrate and morphology (form). However, shoreline substrate and form parameters are reintroduced into mapping and the database as they are coded on a SOS form as part of the individual zone information within each segment or sub-segment. Standard procedures, where pre-spill mapping is not available (or if existing mapping is of poor detail, out of date, or there are observed conditions that may affect treatment considerations not documented on existing mapping), are to break zones within segments if the shoreline character changes significantly (e.g. from vegetated flat to erosional cut bank), even if the oiling conditions do not change. This allows the data management team to provide documentation on river form and substrate as relates to different bank/bar types, oiling conditions, and treatment options, as the surveys progress without the need to pre-map the river system. Additionally, zones that identify undocumented changes in land use or operational constraints that may affect long-term response decisions and achievement of shoreline treatment criteria can be used to delineate sub-segments for the remainder of the response to facilitate future surveys and operational actions.

River Segmentation Naming Convention

For SCAT surveys on rivers, streams or creeks that have not been pre-segmented or mapped the most practical approach at the outset of a survey program is to begin segmentation at the POE of the spilled oil into the river system using the approaches described in the preceding section. The segmentation naming convention or hierarchy for rivers, streams, and creeks in this situation differs from that practised on marine and freshwater shorelines as the extent of the affected area is clearly defined. A typical hierarchy would have large-scale Operations Divisions created initially for strategic and logistics planning (Table 5.3). These divisions are independent of a SCAT segmentation process but nevertheless important as they are recognized by managers at the strategic decision level. Reach Groups are created during the survey program by the SCAT team to summarize large scale (multi-kilometre) river regions or oiling characteristics; as an example, the segments immediately downstream of the POE typically are an area with highest oil concentrations on the banks and can be grouped for specific operational planning purposes.

By contrast, pre-incident segmentation and mapping does not have a “starting point” and is based on a hierarchy of subdivisions creating unique Segments within a larger mapping framework. The segmentation naming convention or hierarchy for rivers, streams, and creeks does not differ significantly from that practised on marine and freshwater shorelines (Section 5.3.1). The higher levels in the hierarchy (1-2) provide a Geopolitical Reference (SK/ASB), and the lower levels (3-6) define the individual sections of shoreline or Mapping Units (KLV-01-RB) (Table 5.4).

5.4 Geographic response plans

A Geographic Response Plan (GRP) is a document that provides geographic-specific information intended to assist responders during the initial phase of a spill response. The availability of this information enables responders to take appropriate response actions at the onset of an incident. A GRP may be a component of an Area Response Plan (ARP) or other Emergency Response Plan (ERP) which encompass a larger area and provides the overarching structure for an integrated response.

The overall objective of a GRP is to provide proven tactical direction and response actions for the initial response, and to assist responders by identifying the location of sensitive resources and spill management points. Maps and tactical sheets [i.e. Tactical Response Plans (TRP)] are used to provide relevant spill management point information, such as best locations to deploy containment and recovery equipment and logistical and operational response features, such as boat launches and staging areas. The GRP also contains logistical information, such as hotels, restaurants, heliports, airports and potential Command Post (CP) locations.

GRPs and TRPs are highly operational plans to ensure swift and efficient response in case of an incident. They provide advanced emergency response planning information to response crews principally in the form of Spill Management Points (SMPs) or Tactical Control Points (TCPs). These are strategic locations where response equipment may be deployed safely and efficiently to prevent further oil migration and facilitate recovery or protect sensitive resources. Typically, each point has its own tactical sheet of site-specific information including location, access considerations, characteristics of the waterway, recommended response tactics and necessary equipment as summarized in Table 5.5.

Culturally and environmentally sensitive receptors need to be protected and preserved in the event of a release. Receptors in freshwater environments may include a wide variety of sensitivities, such as drinking water intakes, water wells, protected areas, federal, provincial, and municipal parks, aboriginal reserves, wetlands, and species of concern. The sensitivity information found in GRPs is intended to support the Environmental Unit (EU) and help ensure consistency and coordination in the approach taken to protect sensitive resources during oil spills. Engaging stakeholders and Indigenous communities during the development of a GRP is an important process and can ensure that vital local knowledge is captured.

A key challenge for freshwater response planning, particularly on rivers, is identifying suitable access points. Access points may be rare in remote areas or where river access is difficult, making vessel transit times and therefore response times longer.

All actions in a response should be modified to meet the demands of a specific incident. The GRP plan does not direct actions, but merely serves as a resource to responders. The strategies and tactics described in a GRP document may need to be adjusted to consider environmental conditions observed at the time of an incident.