Environment and Climate Change Canada (ECCC) has developed a series of field guides to provide technical support tools for decisions regarding the evaluation of freshwater and marine shorelines and treatment options during an oil spill response. The new Freshwater Shoreline Response Guide is aligned with and complements the most recent editions of the ECCC Shoreline Cleanup Assessment Technique (SCAT) Manual (ECCC, 2018) and the ECCC Field Guide to Oil Spill Response on Marine Shorelines (ECCC, 2016). ECCC is engaged to provide science-based information to the spill response community and develop an expertise in spill response.
The purpose of the Freshwater Shoreline Response Field Guide is to provide advice and guidance on the protection and treatment of freshwater shorelines threatened or affected by an oil spill. This Field Guide focuses on conventional tactics normally available to responders and appropriate for freshwater shoreline environments. The content of the Field Guide is organized to describe key elements of:
Health and safety for field teams
Net Environmental Benefit Analysis (NEBA) / Spill Impact Mitigation Assessment (SIMA)
Oil fate and behaviour in freshwater environments
Response – planning, treatment, special topics, and completion and monitoring
This Field Guide includes stand-alone “Shoreline Information Sheets” for shoreline protection tactics, different types of freshwater shoreline substrates, and shoreline treatment tactics. These information sheets have been developed as a quick reference for planners and field responders, and to provide a visual reference for the range of tactics that may be considered during an oil spill response.
Key learnings from inland oil spill responses that occurred in the last 25 years and the freshwater environment expertise of the project team were important sources of knowledge used to develop this Field Guide.
The volume of renewable freshwater in North America is phenomenal. The US has approximately 3,069 cubic kilometers and Canada approximately 2,902 cubic kilometer (World Atlas, 2019) of freshwater. More than 75% of the freshwater is surface water from rivers, lakes, ponds, wetlands and reservoirs. It is practically impossible not to cross a water body during the transportation of hazardous materials across the country. Rails, pipelines and roads often cross or pass adjacent to water bodies and the risk of having an impact during an oil spill is significant. Part of the mandate of the Emergencies Science and Technology Section (ESTS) at ECCC developed tools to support the response during an incident in freshwater environments. The development of a new Freshwater Field Guide including response along shorelines and on the water was aligned with and complements the other field guides: SCAT Manual (ECCC, 2018) and the Field Guide to Oil Spill Response on Marine Shorelines (ECCC, 2016).
Several lessons learned from oil spills in freshwater environments in Canada, the US and internationally came to support the creation of this Field Guide and it provides responders strategies and tactics adapted for freshwater shoreline environments with emphasis on the protection and treatment of spills.
The primary objective of an oil spill response operation is to ensure the safety of the public and responders in the immediate area and to minimize adverse effects on the environment, including essential infrastructure, such as municipal water intakes. Response operations in freshwater environments are not significantly different than any other response. Decision makers identify the risk factors and the preventives measures, the site control and communications and the personal protective equipment appropriate for the type of incident. However, freshwater environments are different from marine in several ways (Sergy and Owens 2011) and it is important to take into account these differences in the evaluation of the risks.
This Field Guide is intended to help the decision-makers before, during and after an incident in a freshwater environment for planning, operations and recovery.
2 FRESHWATER ENVIRONMENTS
Freshwater environments have a different dynamic than marine shorelines and the shore zones are defined in relation to seasonal or annual water levels and the swash zone rather than to the tidal environment (Table 1).
Lake classifications may be based on seasonal variations in water level and volume and as many as eleven major lake types have been identified: tectonic lakes, volcanic lakes, landslide lakes, glacial lakes, solution lakes, fluvial lakes, aeolian lakes, shoreline lakes, organic lakes, anthropomorphic lakes, and meteorite lakes (Hutchinson, 1957). Lakes are commonly classified by their biological productivity or trophic level and range from oligotrophic (low productivity) to eutrophic (high productivity) with mesotrophic conditions in between which affect the lake bed (Figure 1).
SWASH ZONE SHORELINE TYPES
The swash zone is that zone on a lake shoreline where oil is most likely to be stranded and where treatment would be conducted (Table 2). The substrates of the swash zone types that have been defined for this Field Guide can change according to the type of ecosystem (boreal, grassland, forest, etc.).
There are significant differences between freshwater and marine environments in terms of water density, fetch, water levels and flow. Waves are generated by local winds or on distant parts of a large lake in the same manner as waves propagated on marine waters travel as swell towards a shoreline. The water levels on lakes vary in the long-term (annually or monthly and seasonal) and short-term (hours to weeks) depending on precipitation, seasonal snow and ice melting, and water storage in contributing rivers. Lake levels can be controlled by external (upstream) storage or release events on contributing rivers and streams or regulated by water control structures (dams, weirs). Importantly, ice may form on lake and pond waters anywhere in Canada as soon as air temperatures drop below freezing. Ice can form in open waters, as shore fast ice, or as the growth of an ice foot, with the latter two forming earlier and persisting later in the season than on-water ice. These and other shoreline ice features may act to absorb or reflect waves. In winter months, the formation of these features may outweigh the role of waves as a factor in influencing oil movement and behavior on lake shorelines.
2.2 RIVER AND STREAMS
The three primary river channel types at the most generalized level are based on the dominant substrate type of the system:
Bedrock; composed almost entirely of exposed rock;
Alluvial or unconsolidated; a sediment cover of varying thickness above bedrock;
Manmade; comprised of either solid or permeable substrates.
The Active Channel Margin Type is at the waterline, which varies within the Active Channel (Figure 2).
The waterline varies through time and it is the zone of river or stream bank where oil is most likely to be stranded and where treatment would be conducted. The substrates of the Active Channel Margin Types that have been defined for this Field Guide are listed in Table 3.
River character can be classified in several ways and, depending on the system, some or all of which may be applicable. The most applicable approach for spill response purposes is to document and describe the character of the valley which is occupied by the river channel(s), as this is important with respect to access and staging, and the character of the channel itself within which the river or stream flows. These are described in the guide: valley form, channel form, small or intermediate channel/high gradient and large channel/low gradient.
Rivers are dynamic and highly variable environments with respect to currents and water levels. The most significant feature of rivers, streams and creeks is that, for the most part, the flow is one direction. Wave action is typically not a significant hydrodynamic factor but wakes from large vessels and small boat traffic can cause wave heights of 1 m or greater at the active channel margin. Winds may be important with respect to oil transport as they can drive a slick against one bank and keep a lee shore oil free. River, stream, and creek discharges vary constantly in response to changing inputs to the drainage system from precipitation, storm runoff, groundwater and snow/ice melt in the local and upstream areas.
Flow direction and velocity typically varies locally, and back eddies or whirlpools are common as a river or steam channel varies in width and/or depth and near shoals, bars, and islands. Water levels vary constantly in response to changing discharge volumes and can result from ice or large woody debris jams. Two critical effects of changing water levels are that the substrate character and the channel morphology typically change with rising or falling water levels. Seasonal water level changes result from a combination of precipitation, storm runoff, groundwater and snow/ice melt in the local and upstream drainage basin.
3 OIL FATE AND BEHAVIOUR IN FRESHWATER ENVIRONMENTS
The Field Guide has a chapter to explain the oil fate and behaviour in freshwater environments. Oil released into the environment changes due to a variety of biological, physical and chemical processes collectively referred to as “weathering”. These processes alter the behaviour and control the fate of oil in the environment. This can affect the selection of appropriate strategies and treatment methods during a response.
The description of four processes is presented in the Field Guide as:
the transport and weathering processes when oil is released in a freshwater environment or is stranded on lake shores or river banks;
the physical/chemical properties, behavioural characteristics, and potential adverse effects of various types of oil in freshwater;
natural attenuation of oil on shorelines;
ice and snow, and the effects of winter conditions on oil behaviour and weathering;
Some of the key factors that differ between spills in freshwater and marine environments are explained through fundamental aspects of shoreline treatment decision-making and response (including SCAT and shoreline treatment objectives, strategies, and tactics). There are important differences between freshwater and marine environments due to variations in water levels and water exposure/processes in tidal, lake and flowing water environments, which in turn affect oil stranding, oiling band width and behaviour, and natural removal potential and treatment tactics. Some of the basic differences between fresh and marine environments that may affect oil behaviour and oil spill response include water density, fetch, water levels and flow, biological environment, and water intakes.
4 RESPONSE - PLANNING
During an oil spill response, a key objective is to minimize any effects on resources at risk and to develop a shoreline response program. There exist clear differences between the scope of response plans for spills to small creeks and streams, rivers, and lake or marine coasts. 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.
The guide describes the primary functions of a Shoreline Response Program (SRP) and shows specifically how to segment lakes, streams, and rivers for operational considerations (figure 3). 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 Point of Entry (POE) of the spilled oil into the river system (Owens and Reimer 2018). For a multi-channel river, the same Kilometer Point (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. 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.
5 RESPONSE – OPERATIONS
The freshwater environment exposes Operations to different situations. Responders must assess each situation, obtain key information, and determine the oil's trajectory before deciding on the best location to intercept the oil and on which strategies and tactics will be most effective. In lakes or slow-moving water there is more time to make such decisions, however in fast-moving water this assessment must be done relatively quickly. There exist several tools to estimate the speed of the river: current meters, speed test in the river with a branch, etc.
Another challenge that Operations may encounter is the natural collection areas where floating woody material accumulates and strands (Figure 4). In this situation, removal should be considered at these sites in advance of the arrival of oil to minimize the amount of material that may become oiled or that could damage equipment.
There is specialized response equipment for freshwater environments and the response equipment used must be safe and effective for the environmental conditions, for example: walking excavator, skimmers designed for fast flowing water, river boom, etc.
The Field Guide addresses the physical or mechanical tactics and techniques that can be used in the nearshore and at the shoreline to implement a shoreline protection strategy in open-water conditions. To help visualize the available techniques for responders, the Guide has eight Shoreline Protection Information Sheets (e.g. in Figure 5) in which information is presented using six sections: objectives, description, safety notes, applications, overview of tactic consideration(s) for specific conditions and Operational limiting factors and potential solutions. A Shoreline Protection Decision Guide was developed to provide a quick reference for selecting shoreline protection tactics for lakes and ponds and rivers and streams.
TREATMENT APPROACHES FOR DIFFERENT TYPES OF SUBSTRATE
To aid decision-makers, a treatment approach for different types of substrate is necessary. The types of substrates referred to in this Field Guide follow ECCC's shoreline classification system (Sergy, 2008 and ECCC, 2016), which is based on substrate character (material) and shoreline morphology (i.e. form) (Table 4).
Each of the seventeen freshwater shoreline substrates (Figure 6) is described using the following sections: definition and character, oil behaviour, sensitivity, safety notes, preferred treatment options, response considerations and best practices.
SHORELINE TREATMENT TACTICS
The last set of information sheets in the Field Guide are the shoreline treatment information sheets (Figure 7) which describe the different types of techniques used to treat oiled freshwater shorelines. Many options should be evaluated to establish the best approach for treatment of an affected shoreline. Typically, the treatment of an oiled shoreline involves a phased approach with separate response objectives and shoreline treatment criteria for each phase. It is important to note that natural recovery is often the preferred response and the net environmental benefit of treatment versus natural recovery should be considered on a case-by-case basis.
Treatment techniques are recommended to be compatible with the character of the shore zone and with the oiling conditions (type and volume of oil) as documented by the SCAT process and considering a range of operational parameters (Table 5). Most rivers and streams undergo relatively large seasonal variations in water level and flow, and this should be considered in the selection of shoreline treatment tactics and timing of application. For example, over the course of a season, the zone of oiling may be completely submerged or exposed.
Waste management poses a significant challenge for any oil spill response and the freshwater environment is no exception. The volume of waste generated is largely influenced by: the volume of oil spilled, the oil type and weathering stage, the type of shoreline substrate, the treatment techniques and the treatment target criteria.
The Field Guide describes the oily waste types by categories and explains how to develop a waste management plan for each incident. This plan is highly dependent on the identification of response strategies and these activities must be closely coordinated.
6 RESPONSE – SPECIAL TOPICS
Other topics concerning water levels and oil, response in fast water, small and large woody material, subsurface oil on sediment beaches, banks or bars, submerged and sunken oil, oil detection canines and unmanned aerial systems (UASs) are in a special section of the Field Guide. These topics cover several potential questions that may arise the Operations in a freshwater environment and help to detect and delineate oiling on shorelines. For example, many challenges exist for the detection and delineation of submerged and sunken oil, so a range of techniques are described for the nearshore, shallow-water environment.
7 COMPLETION AND MONITORING
Response objectives are broad statements of guidance necessary for the selection of appropriate response strategies and tactics. Specifically, shoreline treatment criteria or standards are developed for each section of shoreline (i.e. segment) to facilitate treatment decision-making and guide Operations during the response. Because each freshwater oil spill is different, treatment criteria must be developed for each response. Shoreline types, oil type and behaviour, sensitivities, land use, access issues, safety, and net environmental benefit of various response tools will affect the decisions around treatment criteria. Examples of treatment criteria of what was developed for some freshwater incidents are provided in the Field Guide; 16TAN Based Objectives, South Salmo River criteria, Lemon Creek treatment criteria (Table 6), etc.
INSPECTION AND COMPLETION
For treatment of a given segment of shoreline that is considered to have been completed, there should be a formal process for inspection and completion. This includes post-treatment surveys where SCAT teams determine if the segment meets the treatment criteria, gain consensus in the field, and generate a Shoreline (or Segment) Inspection Report (SIR) documenting the results. The Field Guide describes this important part of the response.
In conclusion, this Field Guide was prepared to provide technical information with the response community where a freshwater spill poses a risk. In addition to the technical information, several lessons learned from case studies are used to describe best management practices in case of an incident in a freshwater environment. When published, the Field Guide will be distributed throughout the response community as well as available in a downloadable electronic version.
Special thank you to Triox Environmental Emergencies Inc., Owens Coastal Consultants Ltd. and ECCC staff for their involvement and support in the development of this Field Guide.