A field guide to oil spill response on freshwater shorelines: chapter 6

Objective

• Utilize booming and mechanical recovery (skimming or other recovery tactics) in nearshore areas to prevent or limit oil from reaching a specific section of shoreline or sensitive resource.

Description

• Booms surround or contain portions of an oil slick for mechanical recovery.
• Boom is pulled by work vessels in various configurations to contain and recover slick.
• Shallow-draft vessels are often used for nearshore operations and are equipped with:
  • Boom types suitable for forecasted wave and current conditions;
  • Skimmers or other recovery devices appropriate for the type(s) of oil to be recovered.
• Vessel towing speed is typically less than 1 knot (0.5 m/s).

Safety notes

• Booming, skimming, and oil storage or transfer are specialized activities best conducted by trained and experienced responders.
• For substantial spills in larger bodies of fresh water (e.g. the Great Lakes), containment and recovery operations will be conducted by either sheltered or unsheltered waters recovery teams equipped with appropriate vessels and equipment. Specialized sweep/buster systems can be towed at greater speeds, ranging from 3 knots up to approximately 5 knots.

Applications

• Potential for floating oil recovery is high under favourable operating conditions.
• Tactic is appropriate anywhere if it is safe and practical to recover oil.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• For currents of 0.7-1.0 knots (0.4-0.5 m/s) and more, consider use of NOFI Current Buster® Technology systems (up to 5 knots towing speed) and other specialized sweep/buster systems.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Broken or pack ice on nearshore waters constrains the deployment and operation of mechanical recovery systems (booms and skimmers) (Section 6.1.3).
• The most appropriate skimmers for ice-laden waters are oleophilic – units with a recovery mechanism to which oil adheres (e.g. brushes, rope mop).
• Cold temperatures may affect the operation of pumps and other machinery.

Remote areas:

• In locations with little or no local infrastructure to support response operations, on-water containment and recovery is desirable as it limits oil from reaching shorelines where treatment would be required and minimizes the generation of waste

Objective

• Utilize boom or other barriers to deflect or redirect oil (i.e. change the direction of oil movement) away from a specific section of shoreline or a vulnerable resource at risk.

Description

• Redirection booming involves deflecting oil either in nearshore areas or at the shoreline so that it travels in a different direction.
• Boom sections may be deployed in a variety of configurations (single, cascade, chevron, open chevron) to deflect oil depending on:
  • Size/area of approaching slick
  • Amount of deflection needed
  • Flow/current conditions in the boom deployment area
• Deflection of oil may be done in association with containment and recovery on water (e.g. using skimmers; Shoreline Protection Information Sheet 1).

Safety notes

• Shorter sections of boom are typically easier to handle and maintain, thereby increasing safety and efficiency.

Applications

• Used to deflect/redirect oil away from a specific section of shoreline or a vulnerable resource(s) at risk.
• May be used when current speeds or breaking waves preclude exclusion boom (Shoreline Protection Information Sheet 4) or there is insufficient boom available for exclusion.
• Primarily used for:
  • Inland streams with currents >1 knot (0.5 m/s)
  • Across small bays, marina entrances, inlets, river and creek mouths with currents <1 knot (0.5 m/s) and breaking waves <0.5 m
  • On straight shorelines to protect specific areas, where breaking waves are <0.5 m

Overview of tactic consideration(s) for specific conditions

Flowing water:

• In higher flow conditions, deflection is usually more effective than exclusion booming (Shoreline Protection Information Sheet 4), as boom(s) can be set at a higher angle.
• Deploying boom in currents of 0.5 knots (0.25 m/s) or more requires special anchoring techniques.
• Boom with a draft greater than 6 inches (15 cm) is not recommended for currents above 1.5 knots (0.77 m/s).
• For currents of 3 knots (1.5 m/s) and more, a high current sweep system may be required or boom with only a short chain pocket and no more than a 3 inch (8 cm) draft is recommended to maintain a low deflection angle in relation to the current.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Broken or pack ice on nearshore waters constrains the deployment and operation of mechanical recovery systems (booms and skimmers) (Section 6.1.3).ion Information Sheet 2

Objective

• Utilize boom or other barriers to divert or redirect oil (i.e. change the direction of oil movement) to a pre-selected shoreline area.
• Oil is typically diverted towards the shoreline for containment and recovery.

Description

• Diversion booming involves redirecting oil at the shoreline.
• Boom sections may be deployed in a variety of configurations to redirect oil depending on:
  • Size/area of approaching slick
  • Amount of redirection needed
  • Flow/current conditions in the boom deployment area
• Diversion may be used in combination with shore-seal boom to limit contact between the oil and shoreline (Shoreline Protection Information Sheet 5).
• Diversion of oil is typically done in association with containment and recovery either on water (e.g. using skimmers; Shoreline Protection Information Sheet 1) or at the shoreline (e.g. using trenches or sumps to prevent remobilization of oil; Shoreline Protection Information Sheet 6).

Safety notes

• Shorter sections of boom are typically easier to handle and maintain, thereby increasing safety and efficiency.

Applications

• Used to divert/redirect oil towards a location(s) where shoreline treatment may be easier and/or more effective, or to protect specific vulnerable area(s) or resource(s) at risk.
• Primarily used for: inland streams with currents >1 knot (0.5 m/s); across small bays, marina entrances, inlets, river and creek mouths with currents <1 knot (0.5 m/s) and breaking waves <0.5 m; on straight shoreline to protect specific areas, where breaking waves are <0.5 m.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• Install in areas where the current is slowest (i.e. along a straight section rather than a meander).
• Deploying boom in currents of 0.5 knots (0.25 m/s) or more requires special anchoring techniques.
• Boom with a draft greater than 6 inches (15 cm) is not recommended for currents above 1.5 knots (0.77 m/s).
• For currents of 3 knots (1.5 m/s) and more, a high current sweep system may be required or boom with only a short chain pocket and no more than a 3 inch (8 cm) draft is recommended to maintain a low deflection angle in relation to the current.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Broken or pack ice on nearshore waters constrains the deployment and operation of mechanical recovery systems (booms and skimmers) (Section 6.1.3).

Objective

• Utilize boom or other barriers adjacent to the shoreline or around a resource on water to prevent or limit oil from encountering a specific section of shore or a vulnerable resource at risk.

Description

• Exclusion of oil can include nearshore, conventional boom strategies to either provide protection around a specific section of shore or resource at risk or across an embayment or river/creek mouth – oil is excluded and moves in a different direction from what it would follow naturally.
• Other types of barriers include:
  • Bubble barriers – exclude oil from channels (e.g. water intakes) using pumped air
  • Textile barriers – exclude oil from wetlands/emergent aquatic vegetation beds in low-energy environments using textile sheets (e.g. landscape fabric)
• Barriers may also be deployed to contain oil released during flooding or flushing/washing for recovery (Section 6.4).
• Exclusion of oil may be done in association with containment and recovery on water (e.g. using skimmers; Shoreline Protection Information Sheet 1).

Safety notes

• Shorter sections of boom are typically easier to handle and maintain, thereby increasing safety and efficiency.

Applications

• Exclusion booms are deployed across or around sensitive areas and anchored in place to limit contact with oil.
• Primarily used across small bays, marina entrances, inlets, river and creek mouths with currents <1 knot (0.5 m/s) and breaking waves <0.5 m.
• Feasibility limited by water depths and the accumulation or presence of floating material and ice.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• Deploying boom in currents of 0.5 knots (0.25 m/s) or more requires special anchoring techniques.
• Boom with a draft greater than 6 inches (15 cm) is not recommended for currents above 1.5 knots (0.77 m/s).
• For currents of 3 knots (1.5 m/s) and more, boom with only a short chain pocket and no more than a 3 inch (8 cm) draft is recommended to maintain a low deflection angle in relation to the current.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Broken or pack ice on nearshore waters constrains the deployment and operation of mechanical recovery systems (booms and skimmers) (Section 6.1.3).

Objective

• Shore-seal boom (also known as shoreline boom) is used to contain and recover oil at the shoreline.
• This type of boom also reduces the amount of contact between the oil and the shore by creating a barrier that is effective with changing water levels (e.g. wind-driven, increasing/decreasing river discharge). It conforms to the shape of the shoreline, preventing oil from passing underneath at the water’s edge.
• This tactic may also limit the remobilization of stranded oil and oiling or re-oiling at down-drift/ downstream locations.

Description

• This type of boom is designed to maintain a barrier against oil movement as the water level rises or falls.
• Water-filled lower chambers provide ballast and assume the contour of the shore when grounded – the lower chambers also provide a sub-surface oil barrier when afloat.
• Set perpendicular to (i.e. across) the shore to act as a barrier to alongshore oil movement.
• Deploy parallel to the water line to minimize contact between the oil and the shore or to limit stranded oil from remobilizing.

Safety notes

• Shorter sections of boom are typically easier to handle and maintain, thereby increasing safety and efficiency.

Applications

• Shoreline boom provides a seal at the land/water interface that is generally better than that achieved by conventional booms, even in calm water conditions.
• When oil is diverted towards a selected shoreline location(s) for collection and recovery using conventional boom, it may be advantageous to attach one section of shoreline boom to provide a seal at the land/water interface to minimize contact with the shore.
• Primarily on gently sloping shorelines where substrate will not damage/puncture the material.
• Feasibility limited by the accumulation or presence of floating material and ice.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• Effectiveness of shoreline boom decreases with increasing current speed and shoreline slope.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Water in ballast chambers may freeze reducing its ability to contour to the shore – fabric will be damaged if ice pieces puncture the boom.

Objective

• Barriers, berms, sorbents, or sumps are used to contain oil on a shoreline for recovery:
  • As oil strands on the shoreline
  • To limit remobilization of stranded oil
  • To limit waves or rising water levels from over-washing a beach or bank and carrying oil into backshore areas

Description

• Berms can be constructed on a sandy or gravel beach parallel to the waterline to contain oil, with or without a ditch or trench to collect oil as it is washed ashore.
• Ditches, trenches, or sumps can collect oil as it is washed ashore for recovery by skimmers or other physical removal techniques.
• Sorbents can be placed along the shoreline to collect oil as it is washed ashore.
• Barriers or dams can be built across over wash channels to prevent oil from being carried by waves over a beach into a backshore wetland.

Safety notes

• During operation of heavy equipment, a spotter should be present to ensure safe operations.
• Be aware of vapor ignition hazards in areas where oil has been contained by berms or in trenches.

Applications

• Berms or barriers limit oil from being carried over a beach onto backshore areas.
• Oil that is collected in ditches, trenches, or sumps is easier to recover than oiled substrate.
• The feasibility and effectiveness of berms are limited by the size of the area to be protected, the time available to deploy equipment or to construct berms and the substrate type with respect to permeability and porosity.
• Sorbents put on a shore and kept in place by stakes or other anchoring devices may require frequent change-outs – this is labour intensive and can generate a large volume of oily waste materials.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• May be appropriate to utilize in natural collection area(s) with suitable substrate(s).

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Oil may be contained in a trench on solid ice.
• Snow and ice may be used to form effective barriers or berms to temporarily contain oil.

Objective

• Specific vulnerable resources or small sections of shoreline can be protected from contact with oil by using a water barrier, or a physical barrier or cover placed over the shoreline.

Description

• This tactic includes the following options:
  • Flooding (deluge) or low-pressure (high volume) washing hoses are used to form a water barrier and simultaneously move oil away from the shoreline (Shoreline Treatment Information Sheets 1 and 2)
  • A physical barrier, such as plastic sheeting, geotextile, or sorbent material, can prevent contact and protect underlying materials
  • Under the appropriate circumstances and with regulatory approval, chemicals may be applied to either a natural shoreline or manmade shoreline structures to form either a contact barrier or a surface that reduces the adhesion of oil (Shoreline Treatment Information Sheet 15)
• This tactic is only effective if barriers are put in place ahead of oil arrival.

Safety notes

• Make sure all personnel are properly trained to use the equipment and are wearing the right PPE.

Applications

• Water or hydraulic barriers use pumps and hoses with a header placed above the high-water level – nearshore and/or shore-seal booms can be used to contain the oil for recovery (Shoreline Protection Information Sheet 5).
• Physical barriers, such as plastic sheeting, rolls of sorbent materials, or other fabrics (e.g. landscape fabric) may be used – this type of barrier is primarily used for riprap, docks, crib work and other manmade structures where oil would be difficult to access or remove – these permeable structures act as reservoirs for the oil to gradually leach out of if the shoreline is not protected or treated.
• This type of barrier also limits oil from stranding on the shore where logs, branches, or vegetation may be present – it is a slow and difficult process to treat large oiled logs and beaver lodges/dams, particularly in remote areas.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• Oil movement is very rapid – ensure adequate containment and recovery are in place.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.

Objective

• Boom or stationary barriers are used to stop and concentrate moving oil for recovery while allowing water to continue to flow unimpeded.
• Typically used as spill control devices in streams, channels, or inlets where there is a constriction through which the oil must pass.
• May be constructed using locally available materials.

Description

• Boom may be deployed across a calm, shallow water watercourse with a channel width <25 m or downstream of stationary barriers on smaller watercourses as secondary containment.
• Filter fence can be fabricated from available materials, such as fencing or nets, combined with sorbent materials.
• Underflow dam/inverted weir can be built using available materials, such as fill, planks, or sandbags – single or multiple culverts, pipes, and siphons should be designed based on the lowest anticipated water level, flow volumes, and the potential for oil to build up against the dam and become entrained with the water passing through the pipe system.
• Culvert block at the upstream end using impermeable material, such as plywood, sheet metal, culvert plug, clay, etc. – need to monitor water levels to prevent wash out.
• Water-GatesTM function similarly to inverted weirs, but are portable, reusable, easy to install, flexible (i.e. contour to the bed of the watercourse) and reduce environmental effects as they do not require berm construction – require adequate flow to be functional.

Safety notes

• During operation of heavy equipment, a spotter should be present to ensure safe operations.
• Be aware of vapor ignition hazards in areas where oil has been stopped and concentrated.

Applications

• Limit oil from entering backshore or backwater areas through narrow or small inlets.
• Used along stream channels, canals, or ditches to stop and concentrate moving oil for recovery.
• Water flow is maintained using underwater pipes or underflow techniques.

Overview of tactic consideration(s) for specific conditions

Flowing water:

• Oil movement is very rapid – ensure adequate containment and recovery are in place.

Winter:

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Ice, snow and cold temperatures may adversely affect these techniques.

Definition and character

• Bedrock shorelines consist of impermeable outcrops of consolidated native rock, including cliffs (slope face >35°), ramps (inclined slope in the range of 5° to 35°), and platforms (near horizontal with overall slope <5°).
• Resistant bedrock outcrops, such as granites, are stable whereas non-resistant bedrock types, such as the limestone outcrops of eastern Lake Ontario, are easily abraded by ice action and the surface may erode at rates that may be up to several centimetres per year.
• The surface can be irregular, with numerous cracks and crevices, joints and depressions.
• Sediment veneers may overlay bedrock platforms, but the veneers are usually patchy and range from sand to boulders.
• Exposed, high wave-energy and sheltered lower wave-energy bedrock shorelines differ in terms of the character of the shore zone biological communities.

Oil behaviour

• As bedrock is impermeable, stranded oil remains on the surface of the outcrop.
• Oil may pool in depressions on bedrock platforms or ramps.
• Oil that collects in cracks and crevices may not be physically removed by wave and ice action.
• During falling water levels may be deposited as a band, stranding oil above the water line and therefore not in direct contact with running water.
• Oil that comes ashore in sheltered locations is likely to be deposited as a narrow band at or near the water level.
• In sheltered locations, because of the relatively low energy conditions, heavy oils or weathered crude oils may persist for some considerable time (months to years), as there is insufficient energy to naturally remove these oil types.
• Even in sheltered locations, light oils are likely to be washed off a bedrock surface in a short time, i.e. in days to weeks.

Sensitivity

• On exposed shorelines, plants and animals often inhabit cracks and crevices where they are protected from wave or ice action – these are the same locations where oil might be deposited and persist.
• On sheltered bedrock shorelines, sensitivity to oil can be high due to the combination of potential oil persistence and rich biological communities.
• Overall, ice-scoured bedrock outcrops do not have extensive, diverse, or rich biological communities.

Safety notes

• On steeper bedrock outcrops, be extremely careful to avoid slips and falls, particularly on exposed shorelines where there is stronger wave action or ice present.

Preferred treatment options

Response considerations

• Natural recovery is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Natural recovery may not be appropriate immediately before freeze-up as the oil would be encapsulated by ice and potentially remobilized during the next thaw.
• Natural recovery may be appropriate for volatile oils such as gasoline due to safety concerns caused by fumes, ignition, and flashback.
• Oiled material is removed manually, followed by manual removal using hand tools, vacuums, or sorbents on surface oil patches.
• Flooding and ambient low-pressure washing are used along with collection and recovery.
• Under the appropriate circumstances and with regulatory approval, shoreline cleaners may be used with flooding and/or ambient low-pressure washing, followed by oil collection and recovery.

Best practices

• Foot traffic should be controlled to minimize damage to organisms and habitats.
• Generally, avoid washing oil from oiled to un-oiled zones.
• Avoid excessive vegetation cutting as this may kill the plants and remove the protective cover for other organisms.
• The biological effects of high-pressure water washing must be considered, as these tactics can remove healthy organisms.

Definition and character

• These shorelines consist of man-made (anthropogenic) structures that are composed of impermeable materials.
• Solid man-made features and structures vary greatly in design, form, and material – includes structures for moorage (docks, wharfs, marinas), protected anchorages (breakwaters), commercial or industrial activities, and backshore or river bank protection (retaining walls).
• Includes historic structures and archaeological or historic sites.
• Stable, impermeable surfaces consisting of a wide range of materials such as concrete, metal, plastic, and wood – the surface of each of these materials is different in texture and roughness.
• The structure may present a vertical face or be sloped.

Oil behaviour

• Oil generally behaves in a similar way on solid man-made structures as on bedrock shorelines.
• As man-made solid is impermeable, stranded oil remains on the surface – penetration of a few millimetres may occur in open grain woods or concrete.
• Oil reacts to man-made structures in a variety of ways depending on the material and surface texture: concrete (rough), metal (smooth), and asphalt (rough) – oil is more likely to stick to rougher surfaces.
• Oil is more likely to be deposited in the upper half of the swash/active channel zone. The lower swash/active channel zone usually stays wet and often has a biofilm.
• On exposed shorelines, oil may be splashed above the limit of normal wave action.
• Oil that comes ashore in sheltered locations is likely to be deposited as a band at or near the water level.
• In sheltered locations, because of the relatively low energy conditions, heavy oils or weathered crude oils may persist for some time (months to years), as there is insufficient energy to naturally remove these oil types.
• Even in sheltered locations, light oils are likely to be washed off a man-made solid surface in a short time, i.e. in hours to days.

Sensitivity

• Man-made historic, cultural, and archaeological structures typically have a high social value and are assigned a high sensitivity.
• Most other solid man-made structures are relatively low in sensitivity, although their importance and priority will vary with location and human use.
• These shorelines do not have extensive biological communities, as plants are scraped off by ice, though some plants and animals can survive in cracks and crevices.

Safety notes

• As moorings, docks, and walkways are frequently used by people, there is a high potential that people will come in contact with the oil.
• On steep man-made structures or those with shelves, be extremely careful to avoid falls and slips, particularly on exposed shorelines where there is stronger wave action or ice present.

Preferred treatment options

Response considerations

• Historic structures, particularly those made of wood or stone, must be treated as a special case to minimize physical damage or degradation.
• Natural recovery is often the preferred option for low human use areas – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Natural recovery may not be appropriate immediately before freeze-up as the oil would be encapsulated by ice and potentially remobilized during the next thaw.
• Natural recovery may be appropriate for volatile oils such as gasoline due to safety concerns caused by fumes, ignition, and flashback.
• Under the appropriate circumstances and with regulatory approval, shoreline cleaners may be used with ambient low-pressure washing, followed by oil collection and recovery.

Best practices

• Avoid all unnecessary access to oiled man-made historic, cultural, and archaeological structures until there is a special treatment plan.
• Control public access on oiled man-made structures to avoid tracking and spreading the oil.
• Generally, avoid washing oil from oiled to un-oiled zones – frequently the lower swash/active channel zone is not oiled, and more damage can be caused by treatment if oil is washed downslope.
• The biological effects of high-pressure water washing must be considered, as these tactics can remove healthy organisms.

Definition and character

• Man-made (anthropogenic) structures composed of permeable material such as wood and riprap boulders.
• Man-made permeable features and structures include a wide range of designs: such as berms, breakwaters, bulkheads, cribwork, dikes, gabion baskets, piers, retaining walls, riprap and artificial islands. They include shore land extensions, landfill, and areas filled for flood control.
• This shore type includes historic structures and archaeological or historic sites.
• Structures are composed of various sizes of materials with open spaces between pieces leaving them permeable to oil and water penetration.
• Materials include sand, pebbles, boulders, concrete blocks, crushed rock, sand bags, soil, tires, or pre-cast interlocking concrete shapes.
• Common features include riprap, structures for moorage (docks, wharfs and marinas), protected anchorages (breakwaters) or backshore protection (retaining walls).

Oil behaviour

• In each case, an oiled man-made permeable structure would be treated in the same manner as a natural shoreline type with equivalent characteristics.
• For example:
  • Riprap, tires, timber posts, bulkhead of sand-filled bags, and wooden dock are on the same size order as boulders.
  • Gabion mats or baskets would be defined as boulder, cobble or pebble/cobble, depending on the size of the material used.
• The behaviour of oil on made-made permeable structures is similar to natural sediments and a function of the material size.

Sensitivity

• Manmade structures of historic, cultural, and archeological value are highly sensitive.
• Permeable man-made structures are built primarily to stabilize the shoreline or protect docks and marinas.
• Biological productivity is typically higher on permeable man-made shorelines than on solid man-made shorelines as the open pore structure provides additional habitat.

Safety notes

• Structures in zones of high human use present a high potential for human/oil interaction.
• On steep man-made structures, be extremely careful to avoid falls and slips, particularly on exposed shorelines where there is stronger wave action or ice present.

Preferred treatment options

• Preferred response options for removing surface and subsurface oil from permeable man-made shorelines are related to the size of the material in the structure and follow the recommendations and guidelines presented in Freshwater Substrate Information Sheets 6 through 9, which address those types of materials.

Response considerations

• More aggressive treatment strategies and tactics can be considered for man-made structures than for a natural beach consisting of the same material.
• For smaller, heavily oiled structures, such as a cobble-filled gabion basket, it may be more cost- and time-efficient to remove and rebuild the structure than to attempt to treat it.
• Historic structures are usually made of wood or natural or worked stone – they must be treated as a special case to minimize physical damage or degradation.

Best practices

• Avoid large-scale removal of coarse (large-sized) materials as this is not usually practical – removal without replacement will likely lead to shoreline retreat in the form of erosion.
• Generally, avoid washing oil from oiled to un-oiled zones.
• Avoid flushing techniques (e.g. warm or hot water may temporarily mobilize viscous oil) that only move the oil deeper into the shoreline sediments or permeable materials of the structure, unless they also flush the oil out for recovery.

Definition and character

• Sediment cliffs/bluffs are an erosional steep slope composed of unconsolidated or poorly consolidated fine or mixed sediments (loose material such as clay, sand, and gravel).
• Sediment cliffs are defined as >3 m high and the form is vertical or very steep (>35°).
• A sediment cut bank is the outside bank of a channel that is continually undergoing erosion.
• Cut banks are up to 3 m in height whereas a cliff may be tens of meters high, but in all cases, the form is vertical or very steep, typically >35°.
• Erosion is a result of a range of processes that include groundwater flow, currents, surface wash, waves and boat wakes, wind action and rain wash.
• In addition to direct hydraulic erosion, the cliffs can fail by undercutting, slides, slumping, and rotational slips.

Oil behaviour

• Oil would strand at the base of a cliff or bank but may be splashed onto the cliff face by wave/current action. Penetration would vary with oil viscosity and sediment porosity.
• Oil on the cliff face would remain for a short time only (days to weeks) due to natural erosion; oil at the base of the cliff or that is washed from the cliff face either would be buried by material from above or eroded by wave/current action. Buried oil on this receding shoreline would remain until reworked by wave/current action.
• Persistence is primarily a function of shoreline retreat: where this is rapid, the persistence time would be short; in more stable areas, medium or heavy oil on the cliff or in the beach sediments may remain for as much as a year.

Sensitivity

• Minimal biological resources can survive on the surface steep unconsolidated sediments because of their unstable nature.

Safety notes

• Loose, erosional sediments are unstable and provide poor traction for workers on foot.
• Block falls, and slumping are potential safety hazards during any response operations, particularly when the slope is higher than 2 m – these events may occur suddenly and without warning.
• Any techniques that may affect stability of the cliff, such as physical removal of material from the base, should be avoided for safety reasons.

Preferred treatment options

Response considerations

• Natural recovery is often the preferred response option due to the rapid natural erosion of sediment cliffs/ bluffs and cut banks – this option may be less appropriate for medium-heavy or weathered crude oils.
• As erosion by natural processes is normal, treatment activities such as low-pressure washing that cause additional or accelerated erosion are not necessarily considered to be damaging.

Best practices

• Flushing or washing activities may trigger unexpected block falls or slumping.
• In many areas, the beaches that front a cliff/bluff or cut bank are very narrow or absent so there may be little working area.
• Select treatment techniques that minimize erosion – limit the addition of fine sediment to water and/or mitigate increases in suspended sediments in water adjacent to the treatment area and downstream (e.g. utilize silt fencing in water adjacent to treatment area to limit water movement).

Definition and character

• A mud flat (slope <5°) or bank/bar (slope typically 5° to 35° but can be >35°) is dominated by very fine sediments (typically muds, silts, and clays) – may be rich in organic detritus and include small amounts of sand.
• This substrate type is used predominantly in association with riverine environments, but flats may be found adjacent to low-lying areas and inlets to lakes.
• These shorelines are often backed by wetland vegetation and most frequently located in sheltered wave-energy lake environments.

Oil behaviour

• Oil penetration is limited on mud/clay banks because the clay substrate is impermeable – light oils may mix with waters in the sediments.
• Oil will likely not adhere to the substrate if wet or if a vertical clay surface is present.
• Oil is less likely to stay stranded in the lower swash zones as these remain wet due to wave/current action and groundwater flowing out of the beach.
• All oils except those that are highly viscous or dense could be refloated and carried landward by wave action or rising water levels.
• Burial is possible with heavy viscous oils and as a result of storm activity.
• Oil may enter the subsurface through mud cracks or the holes of burrowing animals (e.g. clams and worms) and may have a long persistence time (years).

Sensitivity

• Typically, biological utilization is lower in areas where stronger currents are present in the riverine environment but can be high in sheltered areas.
• Sheltered mud flats can be a primary feeding grounds for birds – may be utilized by migratory species.
• Due to their low weight-bearing capacity, muddy habitats are very sensitive to any activities that mix oil deeper into the sediments where it will persist

Safety notes

• Soft, mud sediments will not support workers on foot without the use of boardwalks (e.g. plywood sheets).
• Sloped, loose, erosional sediments are unstable and provide poor traction for workers on foot.

Preferred treatment options

Response considerations

• In practical terms, there are limited options for removal of oil in this type of shoreline environment.
• To avoid driving oil into the subsurface, less intrusive strategies are preferred – these include herding, flooding or washing, and collection using sorbents or vacuums.
• Natural recovery is the preferred option where this choice exists – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• The weight-bearing capacity of a mud flat may vary from one place to another – some areas may not support the weight of a person or vehicle.
• If the mud is soft, foot traffic should be controlled to minimize negative effects.
• Barges or flat-bottomed boats can be used to support operations and personnel.

Best practices

• Avoid mixing oil into sediments – subsurface oil could persist for a very long time, i.e. years.
• Disturbing sediment can have an effect even in the absence of oil, so all movement of both personnel and vehicles in oiled and unoiled areas must be carefully controlled.

Definition and character

• A sand flat (slope <5°), beach or bank/bar (slope 5° to 35°, but typically 5° to 20°) is composed of sand plus any combination (<10%) of granule, pebble, cobble and/or boulder; silt/clay may be present.
• Sand shorelines are sometimes subdivided based on the dominant size of the sand:
  • coarse sand – larger grain size, steeper slopes, poorer bearing capacity
  • fine sand – smaller grain size, flatter slope, more compacted, provide better traction and higher bearing capacity
• Flats may be found adjacent to low-lying areas and inlets to lakes.
• Sand beaches have a very dynamic, mobile, unstable surface layer.
• Relatively little current or low levels of wave action (e.g. 0.5 m/s currents or 10 to 30 cm heights) can easily change the surface level by several centimetres over short time periods (hours).
• Changes in water flow and level (including large waves), such as from snow melt and rain storms can rapidly redistribute large volumes of sand. These processes can result in erosion, mixing, or burial of stranded oil. Large waves, as would be expected during storms, can lower or raise a beach surface by as much as 1 m in a few hours.
• Sediment supply to sand beaches is highly dependent on local or upstream source and supply conditions.
• Traction usually is good on sand beaches for most types of vehicles. Traction can be a problem in the lower swash zone, where there are water-saturated sediments, or above the normal swash zone, because of soft wind-blown sands. Reduction of tire pressure can partially compensate for low bearing capacity.

Oil behaviour

• Oil penetration is typically limited on sand flats because many sections remain water saturated.
• Sand beaches are permeable for some medium and all light oils – wave action can easily result in mixing, burial or erosion of these lighter stranded oils.
• On a medium- or coarse-grained sand beach, light oils can readily penetrate and mix with groundwater and/or be transported by changing water levels.
• Medium and heavy oils are unlikely to penetrate more than 25 cm because the water table for a sand beach is close to the surface – when wave action occurs, mixing or burial of heavier oils can easily occur due to sand’s mobile properties.
• Oil is less likely to stay stranded in the lower swash zones as these remain wet due to wave/current action and groundwater flowing out of the beach.
• All oils except those that are highly viscous or dense could be refloated by wave action, currents or rising water levels.
• Along exposed shorelines, oil persistence will be short (days to weeks) due to higher wave action.
• Sheltered shorelines generally have longer oil persistence (months to years).

Sensitivity

• Typically, sloped sand shorelines have minimal biological communities due to their higher-energy environments.
• Sheltered sand flats can be feeding grounds for birds – may be utilized by migratory species.
• Sand beaches are common resting or foraging habitats for shorebirds.
• Public and private beaches provide waterfront access to people.
• Seasonal recreational human use significantly increases sensitivity and the potential for people coming into contact with the oil.

Safety notes

• Coarse sand with a steeper slope typically provides poor traction for vehicles and often for workers on foot.

Preferred treatment options

Response considerations

• Natural recovery is the preferred option if possible, particularly for small amounts of oil – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Natural recovery may not be appropriate immediately before freeze-up as the oil would be encapsulated by ice and could remobilize during the next thaw.
• From an operations standpoint, the treatment of oil stranded on sand flats is difficult when the weight-bearing capacity of the sand flat is low.
• Mixing and sediment relocation are more effective on flats with wave or current action.
• Barges or flat-bottomed boats can be used to support operations and personnel.

Best practices

• Avoid removing too much sediment as natural replacement rates are slow in many areas – excessive removal could lead to erosion.
• Activities should avoid mixing unoiled and oiled sediments. Avoid mixing oil into unoiled subsurface sediments except as a planned mixing or sediment relocation strategy.
• Concentrations of oil in the sediment are typically low – removing the sediment generates a large volume of lightly oiled waste, which then requires transfer and disposal.
• Avoid tracking oil into unoiled areas. Vehicles and personnel always work from an unoiled area towards an oiled area to avoid cross-contamination.
• During manual treatment, avoid over-filling collection bags or containers to minimize spillage and to prevent bags or containers from breaking.

Definition and character

• A mixed sediment flat (slope <5°), beach or bank/bar (slope 5° to 35°) is composed of sand plus any combination (>10%) of granule, pebble, cobble and/or boulder.
• The interstitial spaces (voids) between the coarse pebble/cobble fractions are in-filled with sand or granules.
• Mixed sediment shorelines are sometimes subdivided due to differences in oil penetration and treatment tactics selected. The subtypes are:
  • fine-mixed (sand/granule/pebble)
  • coarse-mixed (includes larger cobble material)
• The surface layer often consists predominantly of coarser sediments (pebble/cobble) with increasing amounts of sand/granule in the subsurface.
• The lower swash zone is often predominantly sand.
• The lower bank and mid-channel bars are often characterized by pebble/cobble from which most of the sand has been washed away, leaving a coarse sediment surface layer overlying mixed sediment – sand/fine sediments tend to accumulate where currents are slow.
• Natural supply of coarse sediments is usually a very slow process.

Oil behaviour

• The coarse fractions (pebble/cobble) are in-filled with the finer sands and granules – how the oil behaves is determined more by these finer fractions.
• Oil residence time or persistence is primarily a function of the type of oil, the depth of penetration or burial of the oil, and energy (wave, current) levels on the shore.
• Depth of oil penetration is primarily a function of the viscosity of the oil. Depth of burial or re-exposure of oiled sediments is primarily a function of physical sediment reworking by water processes.
• Light oils can readily penetrate and mix with groundwater and/or be transported by changing water levels.
• Heavy oils penetrate through the mixed sediments less readily than on a coarse sediment beach – oil that does penetrate, however, is more likely to persist in the subsurface of a mixed sediment beach.
• Oil is less likely to stay stranded in the lower swash zones as these remain wet due to wave/current action and groundwater flowing out of the beach.
• All oils except those that are highly viscous or dense would be re-floated by currents or a rising water level.

Sensitivity

• As few animals or plants can survive the continuous reworking of the coarse sediments, exposed or semi-exposed beaches support little life, particularly in the upper swash zone.
• Sensitivity is higher in the lower zones of the beach or in sheltered wave environments that tend to be more stable and where organisms are more likely to be present.

Safety notes

• Mixed sediments typically provide poor traction for vehicles and often for workers on foot.

Preferred treatment options

Response considerations

• Natural recovery may be an acceptable option for small spills, low viscosity oils, or on exposed shoreline, and/or in remote areas – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• When selecting manual and mechanical removal techniques, the following factors must be considered:
  • size of the area to be treated
  • time available for treatment
  • amount of oiled sediment that requires handling, transfer, and disposal
• Manual removal and vacuums can be combined with the use of sorbents on surface oil patches.
• Low-pressure ambient temperature washing with trenches or sumps to collect oil can be combined with vacuum systems to recover the oil.
• Sediment relocation can be followed by mechanical mixing.
• Mixing can be followed by bioremediation as a final polishing tactic.

Best practices

• Excessive removal of sediment can lead to erosion.
• Excessive removal of coarse sediments is of concern as natural replacement rates are usually very slow.
• As concentrations of oil in sediment are usually very low, manual tactics for removing sediment may generate large volumes of waste that contain relatively small amounts of oil.
• If there are attached plants in unoiled lower swash zone and nearshore littoral area, avoid spreading oil into these areas.
• Flushing techniques that only move the oil deeper into the sediments, without flushing the oil out of the shore for recovery, are not appropriate.

Definition and character

• A pebble/cobble beach or bank/bar (slope 5° to 35°) is clearly dominated by either pebbles or cobbles or a combination of both.
• The interstitial spaces (voids) between individual pebbles or cobbles are relatively open and not in-filled with finer material.
• Pebble/cobble beaches have a dynamic, mobile, unstable surface layer.
• The lower bank and mid-channel bars are often characterized by pebble/cobble from which most of the sand has been washed away, leaving a coarse sediment surface layer overlying mixed sediment – sand/fine sediments tend to accumulate where currents are slow.
• Natural supply of coarse sediments is usually a very slow process.

Oil behaviour

• Permeable to all but the semi-solid oils therefore subsurface oiling is typical.
• Oil residence time or persistence is primarily a function of the oil type, depth of penetration, location with respect to the water level, and the wave energy/water flow conditions (current and energy). Typically, only the surface layer of sediments is reworked by normal water movements.
• Depth of oil penetration is a function of the oil type (viscosity) and the sediment size – the larger the particle size the easier it is for oil to penetrate.
• Oil that penetrates below the surface may not be physically reworked except during infrequent, high-energy storms or run-off events
• Oil is less likely to stay stranded in the lower swash zones as these remain wet due to wave/current action and groundwater flowing out of the beach.
• All oils except those that are highly viscous or dense could be refloated and carried up the beach by a rising water level.

Sensitivity

• As few animals or plants can survive the continuous reworking of the coarse sediments, exposed or semi-exposed beaches support little life, particularly in the upper swash zone.
• Sensitivity is higher in the lower sections of the beach or in sheltered wave environments that tend to be more stable and where organisms are more likely to be present – habitat and protection are provided within the interstitial spaces of larger materials such as cobbles.

Safety notes

• Coarse sediments typically provide poor traction for vehicles and often for workers on foot.

Preferred treatment options

Response considerations

• Natural recovery may be an acceptable option for small spills, low viscosity oils, or on exposed shoreline, and/or in remote areas – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Removal of oiled material can be followed by manual removal, vacuums, or use of sorbents on surface oil patches.
• Flooding and low-pressure washing are a good combination.
• Sediment relocation can be followed by mixing and/or bioremediation.
• Sediment relocation depends on the availability of mechanical wave energy to abrade, redistribute, and replace the sediments.
• Sediment relocation in low wave-energy environments requires mechanical energy or the presence of fines (clays and silts) to remove oil.

Best practices

• Excessive removal of sediment can lead to erosion.
• Excessive removal of coarse sediments is of concern as natural replacement rates are usually very slow.
• As concentrations of oil in sediment are usually very low, manual tactics for removing sediment may generate large volumes of waste that contain relatively small amounts of oil.
• If there are attached plants in unoiled lower swash zone and nearshore littoral area, avoid spreading oil into these areas.
• Flushing techniques that only move the oil deeper into the sediments, without flushing the oil out of the shore for recovery, are not appropriate.

Definition and character

• A boulder beach has an unconsolidated accumulation of boulders in the shore zone.
• A useful rule of thumb to differentiate between boulders and bedrock outcrops is that boulders typically are less than 4 m in size.
• Boulder beaches are highly permeable.
• Boulders provide a stable surface layer that can only be moved by humans and extreme wave/flow conditions.
• Mixed sediment (sand, pebble, cobble) is common at the base of the boulders or in the subsurface.

Oil behaviour

• Oil stranded on the upper exposed surfaces of the boulders behaves similarly to oil on bedrock.
• Oil has easy access through the large spaces between the individual boulders, thus coating the inner protected faces of the boulder surface and penetrating underlying sediments.
• Oil residence time or persistence is primarily a function of the type of oil, location with respect to the water level, and the wave energy/water flow conditions (current energy).
• Persistence of oil varies greatly between exposed boulder surfaces and protected crevice and subsurface locations.
• Light or non-sticky oils may be easily flushed out of the sediments on the surface or subsurface.

Sensitivity

• This type of beach is stable, and the boulders provide different types of wave/flow exposures and habitats for biological growth.
• Productivity and sensitivity of biological growth can be relatively high, except in areas where boulders are abraded or moved by ice action in winter or by high flow events.

Safety notes

• Coarse sediments typically provide poor traction for vehicles and often for workers on foot.

Preferred treatment options

Response considerations

• The outer exposed surfaces of boulders are similar in some ways to a bedrock outcrop and can be treated using similar techniques.
• The inner protected surfaces of the interstitial spaces are very difficult to access and the options for oil removal are limited.
• In most cases, all but surface oil would be difficult to recover.
• Natural recovery may be an acceptable option for small spills, low viscosity oils, or on exposed shoreline, and/or in remote areas – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Removal of oiled material is followed by manual removal of surface oil.
• If oil can be removed from the difficult-to-access inner surfaces by washing, this should be done before the oil weathers and decreases the effectiveness of removal.
• Under the appropriate circumstances and with regulatory approval, shoreline cleaners may be combined with flooding and/or ambient low-pressure washing and oil collection and recovery.
• If oil leaching is a concern, the boulders could be lifted out mechanically, either from the land side or from a barge, the subsurface oil removed or treated, and the boulders replaced.

Best practices

• It is not practical or effective to remove boulders from this type of shoreline.
• Boulders form a strong armour layer and would not be replaced naturally. Removal without replacement, therefore, could lead to erosion.
• If there are attached plants in unoiled lower swash zone and nearshore littoral area, avoid spreading oil into these areas.
• Flushing techniques that only move the oil deeper into the sediments, without flushing the oil out of the shore for recovery, are not appropriate.

Definition and character

• Vegetated shorelines or channel margins are stable and consist of cohesive terrestrial or water tolerant vegetation alongside swash zone or bed of a river, creek or stream.
• More common in prairie, muskeg, and tundra regions – regions of flat topography where water flow for most of the year is slow.
• The vegetation can consist of any type (herbaceous, shrub, willow, and/or tree) with >25% ground cover.
• Includes tree branches overhanging the shore zone and exposed roots.
• Occasionally these shorelines are flooded by wind-induced surges or high water.

Oil behaviour

• When the water level is high, oil readily adheres to vegetation and will coat the surface.
• If the vegetation is thick, it will help restrict oil from penetrating the vegetation – oiling will be heaviest on the outer fringe of vegetation.
• When the water level is low, there is typically less oiling of the vegetation, and oil will only coat a narrow band of sediment at the high-water mark.
• Natural removal rates can be very slow due to low energy environments and dense vegetation.

Sensitivity

• These shores are biologically rich habitats.
• Vegetation roots contribute to shoreline/channel margin stability – stems slow the velocity of flood waters and winds, reducing erosion.

Safety notes

• Shoreline/channel margin stability may be affected by treatment activities.

Preferred treatment options

Response considerations

• Natural recovery is often the least damaging alternative for treating light and moderate oiling, particularly where access is limited or difficult.
• Manual tactics using shovels or rakes could be used in small, heavily oiled areas.
• Oiled vegetation could be cut and collected.
• Sorbents are effective for fresh crude oil and petroleum products – loose organic sorbents (e.g. sphagnum peat moss – Sphag Sorb®) can be spread on the surface and lightly raked into areas of sticky or liquid oil then removed for proper disposal.
• Loose organic sorbents can be applied by hand or a small sprayer to provide a barrier to reduce the risk of oil exposure by wildlife (e.g. waterfowl, aquatic furbearers).
• Exposed tree/shrub stems and roots may be wiped with sorbent pads, brushes, or other manual methods to remove gross oiling – if gross oiling cannot be removed using these methods, affected roots may be cut-out if bank stability will not be affected.

Best practices

• Avoid trampling vegetation and using heavy machinery as this is likely to incorporate oil more deeply into sediments – walking boards may be used to access areas by foot for treatment.
• Minimize substrate removal and vegetation cropping unless they are very heavily oiled – if vegetation and sediment are removed, only the top 2 to 5 cm of oiled surface should be picked up if possible, to avoid root damage.
• Avoid raking and trampling oil on to living plants.
• Minimize intrusive physical damage by using only low-pressure washing techniques.
• Excessive removal of vegetation (including roots) and/or substrate may contribute to erosion.

Definition and character

• Shallow-water vegetation near/at water-land interface (e.g. cattails, sedges, grasses) and deeper-water emergent vegetation (e.g. broad beds of emergent aquatic vegetation such as bulrush and reeds found in water depths up to 1.5-2 m).
• Common in sheltered wave-energy environments.
• Support a stable cover of surface vegetation and root system, the leafy portion of which dies back during winter months.
• Dominated by herbaceous vegetation that provides >25% ground cover.
• Wetland types vary significantly in species assemblages, in substrate character and in size.
• Characterized by a surface accumulation of organic matter deposited in water, although inorganic (i.e. mineral) sediments dominate the substratum.
• Extremely productive for plant and animal life and provide habitat to many migratory birds.

Oil behaviour

• Many factors influence how oil affects wetlands: oil type, extent of vegetation contamination, degree of sediment contamination, exposure to natural removal processes, time of year of the spill and species types.
• Most types of oil readily adhere to and are retained on the stems and leaves of vegetation.
• An oiled band forms when floating oil comes in contact with the stems of plants – the width, i.e. vertical height, of this oiled band depends on changes in water levels while the oil is mobile on the water surface.
• If the vegetation is thick, it will help restrict oil from penetrating the vegetation – oiling will be heaviest on the outer fringe of vegetation.
• In some cases, oil trapped in vegetation may be a source of remobilized oil that can be subsequently released to oil or reoil other sites.
• Light oils may penetrate sediments through cracks or holes of burrowing animals and persist in the subsurface sediments for long periods (years).
• Medium and heavy oils will remain on the surface and may smother plants and animals.
• Vegetation dies back seasonally and returns to the aquatic system, either sinking to the waterbody bed or forming decaying vegetation mats on shorelines and banks/bars.
• Natural recovery rates vary depending on the oil type, total area affected, oil thickness, plant type, growth rates, and the season during which the oiling occurred. For example, a reed bed may recover in less than a year or one growth cycle following light oiling.

Sensitivity

• Wetlands are the most sensitive habitats because of their high biological use and value, difficulty of treatment, and potential for long-term effects to many organisms.
• Vegetation roots contribute to shoreline/channel margin stability – stems slow the velocity of flood waters and winds, thereby reducing erosion.

Safety notes

• Shoreline/channel margin stability may be affected by treatment activities.
• Caution should be exercised if wading in water as footing may be unstable and water depth may change unexpectedly.

Preferred treatment options

Response considerations

• Each wetland area should have an individualized treatment plan based on its physical and biological character, and on circumstances of the spill, such as oiling conditions, time of year, size of spill, type of oil, location, and usage of area.
• Due to multiple sensitivity issues, it is often essential to evaluate the net environmental benefit in order to select appropriate tactics and determine how they are used – a specialist may be required to provide judgement calls in this regard.
• Natural recovery is often the least damaging alternative for treating light and moderate oiling, particularly where access is limited or difficult.
• Factors influencing the selection of options include: the rate of natural recovery; the possible benefits of a response to accelerate recovery; and any possible damage or delays in recovery that response activities may cause.
• Natural recovery may not be appropriate near the time of freeze-up as the oil would be encapsulated by ice and potentially remobilized during the next thaw.
• Response activities are best carried out from a boat or using boardwalks or mats to minimize the trampling of plants.
• Flooding and washing techniques that herd oil into collection areas without extensively disturbing the vegetation cover are preferred treatment techniques.
• Loose organic sorbents (e.g. sphagnum peat moss – Sphag Sorb®) can be applied by hand or a small sprayer to provide a barrier to reduce the risk of oil exposure by wildlife (e.g. waterfowl, aquatic furbearers).
• Generally, treatment activities are less likely to damage plants and root systems in late fall during the die-back phase or in winter when the substrate is frozen.

Best practices

• Avoid trampling vegetation as this is likely to incorporate oil more deeply into sediments.
• Trampling of vegetation without oil also directly effects the vegetation – offset these effects by using boardwalks, limiting the number of people and their access, and designating pathways that can be restored after treatment.
• Minimize substrate removal and vegetation cropping unless they are very heavily oiled – if vegetation and sediment are removed, only the top 2 to 5 cm of oiled surface should be picked up if possible, to avoid root damage.
• Minimize intrusive physical damage by using only low-pressure washing techniques.
• Cutting of oiled plant stems during the early or active growing season could affect the plants and should only be considered if leaving the oil would threaten other resources, such as migratory or nesting birds.
• Avoid burning if the lower stems and roots of a plant are dry and therefore not insulated from the heat.
• Excessive removal of vegetation (including roots) and/or substrate may contribute to erosion and delay recovery.

Definition and character

• The active flood plain between the bankfull level and the backshore with continuous terrestrial vegetation that is periodically inundated during high discharge events (seasonal or flood events) in a flowing-water environment.
• The vegetation can consist of any type (herbaceous, shrub, and/or tree) with >25% ground cover.
• May include man-made features, such as residential properties and maintained parks.

Oil behaviour

• Oil on water can enter an upland during a flood event caused by high seasonal water levels, spring melt, rainstorms, diversions or damming. These events raise water levels above the normal channel confines onto the floodplain or backshore uplands.
• When the water level is high, oil readily adheres to vegetation and will coat the surface.
• If the vegetation is thick, it will help restrict oil from penetrating the vegetation – oiling will be heaviest on the outer fringe of vegetation.
• Floating oil may coat or stain trunks, stems and leaves resulting in an oiled band – the width of an oil band would depend on water level changes at the time the oil is still mobile on the water surface.
• Oil would contact the soils along the fringes of the flooded area and as the water recedes to more normal levels.
• Thin sporadic coating of oil could be expected on the soil surface – higher surface concentrations would be created in depressions that trap and hold small oil-on-water pools.
• Stranded oil may be partially buried/buried with silt/clay deposited by receding flood waters.
• Natural removal rates can be very slow due to low energy environments and dense vegetation.

Sensitivity

• Important for terrestrial mammals, birds, and reptiles – can be important recreational areas.
• Vegetation roots contribute to shoreline/channel margin stability – stems slow the velocity of flood waters and winds, thereby reducing erosion.

Safety notes

• Shoreline/channel margin stability may be affected by treatment activities.

Preferred treatment options

Response considerations

• Natural recovery is often the least damaging alternative for treating light and moderate oiling, particularly where access is limited or difficult.
• Manual tactics using shovels or rakes may be used in small, heavily oiled areas.
• Oiled vegetation may be cut and collected.
• Sorbents are effective for fresh crude oil and petroleum products – loose organic sorbents (e.g. sphagnum peat moss – Sphag Sorb®) can be spread on the surface and lightly raked into areas of sticky or liquid oil then removed for proper disposal.
• Loose organic sorbents can be applied by hand or a small sprayer to provide a barrier to reduce the risk of oil exposure by wildlife (e.g. waterfowl, aquatic furbearers).
• Exposed tree/shrub stems and roots may be wiped with sorbent pads, brushes, or other manual methods to remove gross oiling – if gross oiling cannot be removed using these methods, affected roots may be cut-out if bank stability will not be affected.

Best practices

• Avoid trampling vegetation and using heavy machinery as this is likely to incorporate oil more deeply into sediments – walking boards may be used to access areas by foot for treatment.
• Minimize substrate removal and vegetation cropping unless they are very heavily oiled – if vegetation and sediment are removed, only the top 2 to 5 cm of oiled surface should be picked up if possible, to avoid root damage.
• Avoid raking and trampling oil on to living plants.
• Minimize intrusive physical damage by using only low-pressure washing techniques.
• Excessive removal of vegetation (including roots) and/or substrate may contribute to erosion.

Definition and character

• Shoreline or bank is dominated (>75% cover of underlying substrate) by wood and logs that have been deposited on the shore by wave action or currents.
• An unconsolidated accumulation dominated by floating or stranded branches and logs [<10 cm diameter referred to as Small Woody Material (SWM); >10 cm diameter as Large Woody Material (LWM)] diameter that have collected or been deposited on the shoreline, channel margin or floodplain.
• Large woody material deposits provide a stable surface layer. They are moved by ice, human activities, or natural events as might occur during high runoff periods.
• Small and large woody materials can occur along river banks, above or below the water-line or mid-stream, at different levels of submergence.
• Low-lying areas are susceptible to flooding and the inland extent of these incursions is commonly marked by log lines.
• Includes active beaver lodges – the interior of a lodge may have two levels with one or two passageways that may be too small to access for treatment.

Oil behaviour

• An oiled woody material shoreline would be treated in the same manner as a shoreline type with equivalent characteristics.
• Large woody material is on the same size order as boulders and creates a similar gap size and thus should be treated as a boulder beach.
• Large woody material is permeable and has a stable surface layer – oil will adhere to the dry surface.
• Large woody material frequently overlays sand or mixed sediment beaches.
• The large spaces between the individual pieces of trees/logs allow all types of oil to be carried into the underlying sediments.
• Oil stranded on SWM accumulations may bind the materials to create Oiled Debris Mats (ODMs).
• Oil residence time or persistence is primarily a function of the oil type, location with respect to the water level, and wave-energy levels on the shoreline or water flow conditions (current energy).
• Light or non-sticky oils can easily be flushed out of surface sediments due to the large gaps between driftwood pieces.
• High-energy shorelines will generally have short oil persistence (days to weeks) and sheltered shorelines will generally have longer oil residence times (months to years).

Sensitivity

• Minimal biological communities exist on shorelines dominated by large woody material, though plants and animals can be found on or between logs.

Safety notes

• Large woody material may provide an unstable substrate for vehicles and workers on foot.

Preferred treatment options

Response considerations

• The inner protected surfaces of the interstitial spaces are very difficult to access and the options for oil removal are limited.
• In most cases, all but surface oil would be difficult to recover.
• Natural recovery may be an acceptable option for small spills, low viscosity oils, or on exposed shoreline, and/or in remote areas – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Removal of small oiled material is followed by manual removal of surface oil from large material – use chainsaws to cut-out only the oiled parts of branches or logs.
• If oil can be removed from the difficult-to-access inner surfaces by washing, this should be done before the oil weathers and decreases the effectiveness of removal.
• If oil leaching is a concern, the large trees/logs could be lifted out mechanically, either from the land side or from a barge, the subsurface oil removed or treated, and the large woody material replaced – as logs form a strong amour layer, removal without replacement may lead to erosion.
• Disturbance of an active beaver lodge for oil recovery should be conducted in consultation with wildlife agencies to ensure that personnel are not exposed to beaver aggression.

Best practices

• It is not practical or effective to remove large trees/logs from this type of shoreline.
• If there are attached plants in unoiled lower swash zone and nearshore littoral area, avoid spreading oil into these areas.
• Flushing techniques (e.g. warm or hot water may temporarily mobilize viscous oil) that only move the oil deeper into the sediments, without flushing the oil out of the shore for recovery, are not appropriate.

Definition and character

• An accumulation of decaying wood, vegetation, organic matter, or peat.
• Deposits may occur as a mat on a beach or bank/bar or a mobile slurry – tend to accumulate primarily in low-energy, sheltered areas, which is where oil is also likely to accumulate.
• Mats are either wet or dry (“dewatered”), erode easily, and are redistributed by wave or current action.
• May form a slurry at the edge of the beach or shore that resembles “coffee grounds”.
• Channel banks of organic composition are common for streams and rivers flowing through prairie, muskeg and tundra regions.
• Peat shorelines are common along low-lying or sheltered Arctic shorelines – peat is eroded from tundra cliffs.
• If not contained and recovered properly, areas with accumulation may result from the use of sorbents (e.g. sphagnum peat moss – Sphag Sorb®) during the response – these will typically contain oil.

Oil behaviour

• Organic matter has a tendency to absorb and hold oil.
• Heavy oils do not penetrate far into a mat, even if the mat is dry or dewatered, but may be buried or become mixed with organic detritus where it is reworked by wave action.
• Volatile and light oils penetrate organic detritus more easily than heavier oils – if oil penetrates the mat, relatively little recoverable oil may remain on the surface.
• Oils that contact organic slurry are likely to be mixed and remain so, especially in the low wave-energy areas where these slurries typically accumulate – the slurry has a similar effect to that of a loose granular sorbent and partially contains the oil and prevents it from spreading.
• Stranded oil may have a low residence time due to high erosion rates along peat shorelines.

Sensitivity

• Although not typically an important biological habitat, organic shorelines are potential bird-feeding areas.

Safety notes

• Very poor weight-bearing capacity due to low cohesion of decaying organic materials.

Preferred treatment options

Response considerations

• Natural recovery is often the least damaging alternative for treating light and moderate oiling, particularly where access is limited or difficult.
• Natural recovery may not be appropriate near the time of freeze-up as the oil would be encapsulated by ice and potentially remobilized during the next thaw.
• Manual tactics using shovels or rakes could be used in small, heavily oiled areas – then apply mixing to any remaining materials to accelerate physical and biological processes.

Best practices

• Avoid trampling vegetation and using heavy machinery as this is likely to incorporate oil more deeply into sediments – walking boards may be used to access areas by foot for treatment.
• When peat is found in association with tundra (which is a living plant community), minimize substrate removal and vegetation cropping unless they are very heavily oiled – if vegetation and sediment are removed, only the top 2 to 5 cm of oiled surface should be picked up if possible.
• Avoid raking and trampling oil on to living plants.
• Minimize intrusive physical damage by using only low-pressure washing techniques.
• Avoid burning peat or oiled material near living plant communities.

Definition and character

• Tundra cliffs are an erosional feature on Arctic shorelines – they are composed of a tundra (vegetation) mat that usually overlies peat and exposed ground ice with varying degrees of mixed sediment layers.
  • Ice-rich tundra cliffs are primarily composed of a tundra mat, peat and ice, with relatively little sediment – these are generally fronted by sand or mixed sediment beaches.
  • Ice-poor tundra cliffs are unconsolidated sediment cliffs with an overlying surface layer of tundra vegetation and peat and may have minor interstitial ice in the cliff face.
• As the ice-rich cliff face retreats due to wave action or as thermal erosion melts the ground ice, the tundra and peat materials fall to the base of the cliff - initially this material falls as fragmented and irregular blocks until it is reworked by wave action.
• Despite rapid erosion rates, relatively little beach-forming material is supplied to the shore zone so that beaches usually are either narrow or absent in many areas – eroded peat commonly accumulates at the base of a tundra cliff or may be transported alongshore.
• Cliffs range from less than 1 m to as much as 5 or 10 m high in some cases.

Oil behaviour

• Oil that is washed up on exposed ground ice is unlikely to stick and would flow back down onto the beach unless air temperatures are below freezing.
• If there are fragmented or slumped blocks at the base of the cliff, oil may pool in the spaces between the blocks.
• Oil may be splashed on to the top of a low cliff surface where it would be untouched by normal wave action.
• If there is a sand or mixed sediment beach at the base of the cliff, oils may penetrate – if these substrates become oiled, they would be treated as sand or mixed sediment depending upon their character.
• Oil persistence is usually short due to natural erosion – oil persistence may be longer if the oil is buried byblock falls, incorporated into peat slurries, or absorbed into a beach.
• If oil is on the cliff surface or on slumped tundra blocks, it will likely be reworked and remobilized by wave/water action.
• Exposed (high-energy) shorelines will generally have short oil persistence (days to weeks), and sheltered, low-energy shorelines will generally have longer oil residence times (months to years).

Sensitivity

• Minimal biological resources can survive on the surface of tundra cliffs because of their unstable nature, though the vegetation on the tundra is sensitive to disturbance, and migratory birds use these shorelines during the summer months

Safety notes

• As tundra cliffs are often undercut and are naturally unstable, safety is a primary concern during operations.
• Loose, erosional sediments are unstable and provide poor traction for workers on foot.
• Block falls, and slumping are potential safety hazards during any response operations, particularly when the slope is higher than 2 m – these events may occur suddenly and without warning.

Preferred treatment options

Response considerations

• Natural recovery is the preferred response option due to the rapid natural erosion, particularly of ice-rich tundra cliffs – oil on the cliff face, at the top edge of a cliff, or in the tundra and peat deposits at the base of a cliff will probably be naturally removed within weeks provided that the oil is not stranded at the onset of freeze-up.
• Natural recovery may not be appropriate immediately before freeze-up as the oil would be encapsulated by ice and potentially remobilized during the next thaw.
• As erosion by natural processes is normal, treatment activities such as low-pressure washing that cause additional erosion are not necessarily considered to be damaging – any erosion caused by treatment should be minimized, however, as the vegetation on the tundra is a living community.
• Mixing and sediment relocation are more effective on shores with wave action.

Best practices

• Flushing or washing activities may trigger unexpected block falls or slumping.
• In many areas, the beaches that front a cliff/bluff or cut bank are very narrow or absent so there may be little working area.
• Select treatment techniques that minimize erosion – limit the addition of fine sediment to water and/or mitigate increases in suspended sediments in water adjacent to the treatment area (e.g. utilize silt fencing in water adjacent to treatment area to limit water movement).

Definition and character

• The shorelines of these low-lying areas are often complex and convoluted, consisting predominantly of a combination of vegetated flats, peat mats, lagoons, and small streams.
• These areas can include subsiding tundra, ponds or lakes. Areas of flooded tundra polygons have a complex configuration of interconnected ridges with pools that contain decomposing vegetation.
• This type of shoreline is dominated by vegetation.
• Occasionally these shorelines are flooded or inundated by wind-induced surges or high water.
• The landward limits of past surge events are usually marked by lines of woody material.

Oil behaviour

• During the summer, the sediments and/or peat deposits are often water-saturated so that oil would be restricted to surface areas only.
• Vegetation is often water-saturated, which limits oil penetration.
• The tundra has a vegetated soil or peat surface that resists penetration by heavy oil – heavy oils can persist, however, when buried by sediments or peat deposits.
• Light oil and light refined products can penetrate the soil, especially when the soil is dry – when this occurs, there may be relatively little recoverable oil on the surface.
• Residence times for oil on untreated tundra may increase as both the viscosity of the oil and the water content of the tundra decrease.
• Complete removal of the oil by natural processes may be delayed until a storm surge.
• Other substrates may be present with inundated low-lying tundra – wave action may push sand, gravel and driftwood on to the vegetation or peat mat. If these substrates become oiled, they would be treated as sand, pebble, cobble or boulder beaches or bank/bars depending upon their character.
• Natural recovery rates vary, and recovery may take as little as a few years following light oiling but may take decades in extensive, thick deposits of viscous oil.

Sensitivity

• These shorelines are sensitive to trampling and vehicle traffic during the open-water season.
• These shorelines are important for animal life and provide habitat to many migratory birds during the summer.

Safety notes

• Shallow nearshore water may limit access to the site by water and make it necessary to access the site by land – however, the complicated character of the shoreline and the presence of many water saturated sections may make it difficult to access and move on the land.

Preferred treatment options

Response considerations

• Natural recovery is often the least damaging alternative for treating light and moderate oiling, particularly where access is limited or difficult.
• Natural recovery may not be appropriate immediately before freeze-up as the oil would be encapsulated by ice and potentially remobilized during the next thaw.
• Manual tactics using shovels or rakes could be used in small, heavily oiled areas.
• Oiled vegetation could be cut and collected, preferably only on dry surfaces.
• Sorbents are effective for fresh crude oil and petroleum products – the most effective technique in a peat-rich environment might be to use natural peat as a sorbent and remove the most heavily oiled fraction.

Best practices

• Surface disturbance is minimized if treatment is done during winter months when the surface material is frozen.
• Avoid trampling vegetation and using heavy machinery as this is likely to incorporate oil more deeply into sediments. The weight-bearing capacity of these low-lying areas is usually low during the open-water season but increases after freeze-up. In summer, treatment crews could use walking boards or snowshoes to minimize damage and trampling.
• Where the tundra (which is a living plant community) has been oiled, minimize substrate removal and vegetation cropping unless they are very heavily oiled– if vegetation and sediment are removed, only the top 2 to 5 cm of oiled surface should be picked up if possible, to avoid root damage.
• Avoid raking and trampling oil on to living plants.
• Minimize intrusive physical damage by using only low-pressure washing techniques.
• Avoid burning close to living plant communities.

Definition and character

• Under winter conditions or in a cold climate, the shore (underlying substrate) may be covered by snow and/or ice – these conditions are typically temporary but may exist year-round in high latitudes.
• Snow and ice components are combined with the character of the underlying geological substrate of the shoreline to determine response options – oil behaviour and the selection of treatment strategies also consider whether the underlying sediments are frozen or not frozen.
• Shorefast ice (or an “ice foot”) forms on most lake shores and river banks throughout Canada each winter.
• Frozen splash or spray can form a coat of ice on the surface of the substrate.
• Fresh water flowing down slope from the backshore can freeze and may mix with the ice foot or frozen splash and spray.
• Ice floes originating from the break of the lake or upstream sources can be stranded on a shoreline, bank or bar.
• Ice can form by the freezing of water in the interstitial spaces of sediments.
• The character of an ice surface can range from a thin sheet of frozen spray, to a solid ice foot, individual stranded floes, or a wet surface of melting ice.
• The form of shore-zone ice can range from a vertical face to a level or low-angle slope.
• Snow surface character is highly variable, ranging from fresh powder/drifting snow with a soft surface, loose granular, hard/dry/crusty, to wet slush.
• Snow is typically permeable, while ice is impermeable.

Oil behaviour

• Since snow is permeable, stranded oil will be absorbed into the snow and be partially contained by the snow (natural sorbent) – the freeze-thaw process forms ice lenses within the snow that can limit penetration of oil into snow.
• Oil-in-snow content is dependent on oil type and snow character and is lowest on firm compacted snow surfaces in below-freezing temperatures and highest for fresh snow conditions.
• Light oils can migrate laterally hundreds of metres within snow so that detection can be challenging – detection dogs have been used successfully to locate subsurface oil in snow.
• Oil causes snow to melt – for example, crude oils will melt snow but do not spread over a wide surface area.
• The presence of ice in the shore zone helps prevent oil on surface water from contacting shore substrates.
• Ice is impermeable, so stranded oil remains on the surface – oil will not adhere to the ice surface unless air, water and oil surface temperatures are below 0°C.
• Ice in sediments (frozen interstitial or groundwater) can prevent the penetration of stranded oil.
• Where there is broken ice present, without a landfast ice cover, oil may reach the shore and become stranded on the substrate in between the ice pieces.
• Oil persistence on ice and snow is highly variable.
• Oil may freeze onto the ice surfaces and remain stranded until the ice melts – once the ice and snow melt, the oil may then penetrate the underlying substrate and could persist for long periods of time, depending on the substrate and exposure.

Sensitivity

• The snow or ice layer itself is not considered to be a sensitive environment.
• When selecting oil removal tactics, the nature and sensitivity of the underlying sediment or bedrock substrates must be considered.

Safety notes

• If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.

Preferred treatment options

Response considerations

• Natural recovery may be preferred for volatile and light oils that will evaporate during thaw periods unless the oil spill is close to sensitive habitats or populated areas.
• Natural recovery is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• When there is no physical energy to remove the oil, natural recovery does not take place until spring melt and breakup.
• If the adjacent watercourse is ice-free and air temperatures are above freezing, flooding or low pressure ambient-water washing may be practical to flush the oiled snow onto the water surface for containment and recovery.
• Pooled oil on the snow or ice surface, oil that is contained by berms, or oiled snow and that is collected and piled in a suitable location can be removed by burning – this may be suitable in remote areas where minimizing waste is an important consideration.

Best practices

• Implement best practices according to the underlying sediment or bedrock substrates.

Objective

• To allow the oiled shoreline to recover without intervention – the stranded oil is left to natural weathering and oil removal processes.

Description

• Information on the oiling conditions, the freshwater processes and physical character of the shoreline, and the resources at risk must be assessed in order to evaluate the probable consequences of allowing the oil to be naturally removed or to degrade naturally.
• In many circumstances, the site should be monitored over a period to ensure that the assessment is correct or that the rate of weathering and natural oil removal is proceeding as anticipated.
• Natural recovery is the preferred option if possible, particularly for small amounts of oil – this option is less appropriate for medium-heavy or weathered crude oils and in slow moving rivers, backwaters and sheltered shores.
• Natural recovery may not be appropriate immediately before freeze-up as the oil would be encapsulated by ice and could remobilize during the next thaw.

Safety notes

• Care should be exercised as oiled surfaces may be very slippery leading to slips and falls.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Monitoring of sites over the long-term may be more challenging due to logistics and access.
• Winter:
  • Appropriate for winter use.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Useful for remote or inaccessible areas, or areas where it is unsafe for field workers to operate.

Objective

• To flood a site with a large volume of ambient-temperature freshwater so that mobile or remobilized oil is lifted and carried downslope to a collection area.
• To flood a site with a large volume of ambient-temperature freshwater in advance of shoreline oiling to prevent oil from penetrating a porous shoreline (e.g. Pebble/Cobble Beach).

Description

• A large amount of freshwater is used to flood the surface area of impermeable bedrock or solid manmade shoreline or to raise the water table to the surface of the beach in the case of sediment shorelines.
• Mobile or non-sticky oil is transported with the water as it flows downslope due to gravity. The oil is contained with boom and removed from the surface with skimmers other means of collection.
• The high-volume (200 to 1000 L/minute), low-pressure (<20 psi or <1.5 bars) supply of freshwater at ambient temperatures is pumped using large diameter pipes (10 to 20 cm) and/or hoses onto the upper section of the oiled shoreline.
• Water is pumped onto the shoreline either directly from a hose without a nozzle or through a pipe or hose (“header”) that is perforated at intervals with 0.25 to 0.5 cm holes and placed along the upper shoreline parallel to the water line. A flexible hose is better for the latter application, as it conforms to the actual surface of the shoreline being flooded.

Safety notes

• Make sure all personnel are properly trained to use the equipment and are wearing the right PPE.
• Care should be exercised as oiled surfaces may be very slippery leading to slips and falls.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for containment/recovery areas with minimal to no flow.
• Winter:
  • Appropriate for winter use, if conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires very high logistics support and labour.

Objective

• To wash and flush oils at low-pressure, using freshwater at either ambient or warm/hot temperatures, towards a collection area.

Description

• With hand-operated or remote-controlled hoses, freshwater is used to wash, flush, and herd oil to a collection point for recovery and removal.
• Output pressures from the hose are usually controlled by a nozzle and are low (<3 bars or 50 psi) – water is either ambient temperature or heated between 30°C (warm) and 100°C (hot).
• Oil that is flushed or dislodged by the low-pressure hoses is readily carried downslope by the high-volume flow of water.
• Mobile or dislodged oil is transported with the water as it flows downslope, which prevents the oil from being redeposited elsewhere – may be combined with flooding.
• Warm water dislodges and flushes oil that cannot be removed using low-pressure, ambient temperature water.
• Booms or other containment tactics collect the oil for removal.

Safety notes

• Tactic is labour-intensive and equipment must be moved frequently.
• Make sure all personnel are properly trained to use the equipment and are wearing the right PPE.
• Care should be exercised as oiled surfaces may be very slippery leading to slips and falls.

Applications for surface oiling

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for containment/recovery areas with minimal to no flow.
• Winter:
  • Appropriate for winter use, if ice conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires very high logistics support and labour and generates high waste volumes (liquids).

Objective

• To wash and flush oils at high-pressure, using freshwater at either ambient or warm/hot temperatures, towards a collection area.
• Typically used to remove oil that has adhered to hard substrates or man-made structures.

Description

• With hand-operated or remote-controlled hoses with jets, freshwater is used to wash, flush, and herd oil to a collection point for recovery and removal.
• The higher water pressure provides the increased physical force required to dislodge and flush oil that cannot be removed using lower pressure.
• Output pressures from the hose are usually controlled by a nozzle and exceed 4 bars or 60 psi.
• If pressures higher than 70 bars (1000 psi) are used, this technique is commonly referred to as pressure washing – commercial units are available that produce up to 275 bars (approximately 4000 psi) of pressure.
• Water is either ambient temperature or heated between 30° (warm) and 100°C (hot).
• Oil that is flushed or dislodged by the high-pressure hoses is readily carried downslope by the high-volume flow of water.
• Mobile or dislodged oil is transported with the water as it flows downslope, which prevents the oil from being redeposited elsewhere – may be combined with flooding.
• Warm water dislodges and washes tenacious oil that cannot be dislodged by ambient temperature water.
• Booms or other containment tactics collect the oil for removal.

Safety notes

• Tactic is labour-intensive and equipment must be moved frequently.
• Make sure all personnel are properly trained to use the equipment and are wearing the right PPE.
• Care should be exercised as oiled surfaces may be very slippery leading to slips and falls.

Applications for surface oiling

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for containment/recovery areas with minimal to no flow.
• Winter:
  • Appropriate for winter use, if ice conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires very high logistics support and labour and generates high waste volumes (liquids).

Objective

• To remove oil or oiled materials, including oiled sediments, using manual labour and hand tools (e.g. rakes, shovels, sieves).

Description

• Shoreline teams pick up oil, oiled sediments, or oily material with rakes, forks, trowels, shovels, sorbent materials, or buckets.
• This may include scraping or wiping with sorbent materials or sieving if the oil has come ashore as tar balls.
• Collected material is placed directly in plastic bags, drums, or other containers for transfer – if the containers are to be carried to a temporary storage area, they should not weigh more than what one person can easily and safely carry.
• To avoid spilling, containers should not be overfilled or dragged along the ground – collected material can be placed directly into the bucket of a front-end loader.
• This technique can be used practically and effectively in any location, for small amounts of oil on most types of shoreline.

Safety notes

• Tactic is labour-intensive and personnel may be exposed to a variety of weather conditions, such as heat, cold, and rain, and must have the appropriate PPE.
• Personnel safety must also be considered in areas with rapidly changing water levels and when volatile oils are present.
• Care should be exercised as oiled or wet bedrock and pebbles/cobbles can be very slippery leading to slips and falls.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for use on applicable substrates.
• Winter:
  • Appropriate for winter use, but efficiency may be less due to unfavourable weather conditions.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires very high logistics support and labour and generates moderate waste volumes (solids or liquids).

Objective

• To remove oil by suction using vacuums from areas where it has pooled or collected in sumps or depressions.

Description

• Commercially available vacuum equipment is used, which includes small hand-carried or larger truck-mounted vacuum systems – the suction end of these units is usually deployed manually to collect oil and/or oily water.
• These units are not the same as mobile vacuum systems that have a fixed slot or similar suction system mounted below a mobile platform (usually a tank truck) and are not labour intensive.
• Several types of commercially available vacuum units have been designed specifically for shoreline treatment – these involve a pump and small, detachable storage drums (0.2 m³/45 gallons); some feature a dual-head system with water jets to mobilize oil mounted next to a suction head that lifts and recovers the oil/water mixture.
• Vacuums are primarily used when oil is pooled in natural depressions and hollows or has been herded into collection areas, such as lined pits or trenches (Shoreline Protection Information Sheet 6).
• This technique can be combined with flooding or deluge techniques to float and collect oil (Shoreline Treatment Information Sheet 2).
• The dual head wash vacuum system is used in places that are hard to access, such as between boulders.
• Varying quantities of waste are generated depending on the system used and the location.

Safety notes

• Tactic is labour-intensive, and equipment must be moved frequently, and the suction arm must be handled or operated manually.
• It is not safe to use vacuums with volatile oils or oils that cannot be pumped.
• Care should be exercised as oiled or wet bedrock and pebbles/cobbles can be very slippery leading to slips and falls.
• Bearing capacity of shoreline or bridge is adequate

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for areas with minimal or no flow (i.e. natural collection areas).
• Winter:
  • Appropriate for winter use, if conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Portable vacuum units may be appropriate for remote areas or areas with difficult access for heavy equipment.
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique may generate high waste volumes (liquids).

Objective

• To remove oil by suction using vacuums from areas with shallow water (less than 2 m deep) immediately adjacent to the shoreline.

Description

• Commercially available vacuum equipment is manually deployed from the shore or mounted on a floating platform.
• For large amounts of mobile oil, a decanting process is required to separate oil and water.
• For sunken solid particles, such as tar balls, the oil can be collected in a filter or mesh.
• Large concentrate fields/areas of tar balls or tar patties should be contained where required by first installing silt fencing.
• Varying quantities of waste are generated depending on the system used and the location.

Safety notes

• Tactic is labour-intensive, and equipment must be moved frequently, and the suction arm must be handled or operated manually.
• It is not safe to use vacuums with oils that cannot be pumped.
• Care should be exercised as oiled or wet bedrock and pebbles/cobbles can be very slippery leading to trips, slips, and falls.

Applications for surface oiling

• Vacuums are one of the few practical options, along with manual recovery, for removing nearshore sunken oil in shallow waters less than 2 m deep.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for areas with minimal to no flow (i.e. natural collection areas).
• Winter:
  • Appropriate for winter use, if conditions allow.
• Remote areas:
  • Portable vacuum units may be appropriate for remote areas or areas with difficult access for heavy equipment.
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique may generate high waste volumes (organic detritus).

Objective

• To remove oil and oiled materials using mechanical equipment.

Description

• Oil and oiled surface and subsurface materials are removed from shorelines using a range of mechanical devices – mechanical removal is faster than manual removal but generates more waste.
• The method of operation varies considerably depending on the type of equipment available and its ability to operate on a section of shoreline.
• Elevating scrapers, front-end loaders, backhoes, or vacuum trucks can remove and transfer material directly to a truck or temporary storage area in a single step – other equipment, such as graders, sidecast material that must then be picked up by scrapers, loaders, or backhoes for transfer.
• Several mobile beach cleaners have been developed specifically for oil spill shoreline treatment.
• Off-site beach-cleaning machines that treat or wash oiled materials are included with this technique – these involve a waste management program of transfer and temporary storage and treatment, even if sediments are replaced on the shore.
• The suitability of different types of machines for treating oil on shorelines is determined by the weight-bearing capacity of the sediments and the slope of the shore zone, as well as the performance characteristics of the individual equipment.
• Mechanical removal options are different from mechanical in-situ treatment options that do not generate waste materials.

Safety notes

• During operation of heavy equipment, a spotter should be present to ensure safe operations.
• Traction of heavy equipment is typically reduced as sediment size increases.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for use on applicable substrates.
• Winter:
  • Appropriate for winter use, but efficiency may be less due to unfavourable weather conditions.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires access for earth-moving equipment and generates high waste volumes (solids).

Objective

• To remove parts of oiled plants in order to prevent the oil from remobilizing or to protect animals and birds from contact with the oil.

Description

• Vegetation cutting is usually a manual operation whereby scythes, knives, powered weed cutters, and/or rakes are used to cut and collect the oiled vegetation.
• Mechanical cutters can also be used, depending on the conditions at the site (i.e. weight-bearing capacity, access to the site, and the types of plants).
• Floating weed cutters can be used to work close to the shoreline if the water is not too deep.
• Vegetation cutting is primarily used to remove small amounts of oiled vegetation from bedrock shorelines, wetlands, vegetated/wooded uplands, and inundated low-lying tundra – it is suitable for use on a variety of different plants.
• Oil readily adheres to and is retained on the stems and leaves of dry vegetation – if there is extensive oiled vegetation, significant amounts of oil can be recovered by cutting and removing this vegetation.

Safety notes

• Make sure all personnel are properly trained to use the equipment and are wearing the proper PPE.
• Care should be exercised as oiled surfaces may be very slippery leading to slips and falls.
• Some vegetation can cause skin irritation (e.g. Poison Ivy).

Overview of tactic consideration(s) for specific conditions

• Flowing Water:
  • Appropriate for use on applicable substrates or in areas with minimal or no flow.
• Winter:
  • Appropriate for winter use, but efficiency may be less due to unfavourable weather conditions.
• Remote Areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires very high logistics support and labour and generates moderate waste volumes (oiled vegetation).

Objective

• Sorbent materials are deployed to recover oil on the surface of the water or ground.

Description

• Sorbent materials can be used in both protection and treatment mode – they are placed in the shore zone to collect floating oil as it comes ashore or to collect remobilized stranded oil as it leaches off the shoreline and out of the shoreline sediments.
• Commercially available sorbents are supplied as sausage boom, rolls, sweeps, pads, and snare.
• Sorbents can be installed in filter fences in streams (Shoreline Protection Information Sheet 8).
• Includes loose organic sorbents (e.g. sphagnum peat moss – Sphag Sorb®) applied to riverbanks or shorelines/land surfaces to sorb oil or act as a contact barrier (Shoreline Protection Information Sheet 7).
• Loose organic sorbents can be applied by hand or a small sprayer to provide a barrier to reduce the risk of oil exposure by wildlife (e.g. waterfowl, aquatic furbearers).
• Sorbent booms or sweeps are usually fixed in place with stakes and/or anchors in a line or parallel lines to form a floating barrier that moves with the changing water level at the water’s edge.
• In both the protection and treatment modes, the sorbent material is left to collect oil on contact for subsequent removal and disposal.
• Sorbents are often used as a follow-up technique after bulk oil has been removed or in areas where access is difficult.
• In a peat-rich environment, natural peat can be used as a sorbent on fresh crude oil and products.

Safety notes

• Tactic is labour-intensive and personnel may be exposed to a variety of weather conditions, such as heat, cold, and rain, and must have the appropriate PPE.
• Personnel safety must also be considered in areas with rapidly changing water levels and when volatile oils are present.
• Care should be exercised as oiled or wet bedrock and pebbles/cobbles can be very slippery leading to slips and falls.
• Sorbents can become very heavy when saturated – ensure proper lifting procedures and limits are followed.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for use on applicable substrate types.
  • More difficult to keep in place along shorelines exposed to currents.
• Winter:
  • Appropriate for winter use, if conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires very high logistics support and labour and generates high waste volumes (oiled sorbents).

Objective

• Dry mixing of oiled sediments on land to break up and oxygenate oil residues to accelerate natural weathering and removal processes without removing sediment.

Description

• Oiled sediments are agitated by tilling, raking, digging, or ploughing actions that physically turn over or displace sediments on the surface and subsurface.
• Rotary garden tillers or rakes are used to manually mix the sediments.
• For larger applications, heavier machinery is used including agricultural equipment (e.g. disc systems, harrows, ploughs, rakes or tines) or earth-moving equipment (e.g. rippers/tines, front-end loaders, backhoes, graders, or bulldozers).
• The weight-bearing capacity of the sediments will determine which types of equipment to use.
• Agricultural “rippers” or “scarifiers” usually break up sediments to a depth of 50 cm whereas backhoes dig to significantly greater depths, i.e. on the order of 1 m or more.
• There is no removal of oiled sediments associated with dry mixing.

Safety notes

• During operation of heavy equipment, a spotter should be present to ensure safe operations.
• Traction of heavy equipment is typically reduced as sediment size increases.
• Safety evaluations are crucial to ensure that volatile fractions are not present in the oil.

Overview of tactic consideration(s) for specific conditions

• Flowing water:
  • Appropriate for use on applicable substrates.
• Winter:
  • Appropriate for winter use, if conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires access for earth-moving equipment.

Objective

• Wet mixing is used to release and recover surface or subsurface oil by physically agitating sediments in shallow water (less than 1 m deep) on site.

Description

• Wet mixing is used in shallow water (less than 1 m deep).
• The sediments are agitated in situ to release the oil by physical abrasion.
• The released oil is recovered within the containment area by skimmers or sorbents.
• Oiled sediments can be mixed using agricultural equipment (e.g. disc systems, harrows, ploughs, rakes or tines) or earth-moving equipment (e.g. rippers/tines, front-end loaders, or backhoes/excavators).
• Water jets, either high-volume + low-pressure or low-volume + high-pressure, can also be used to agitate the underwater sediments within a boomed containment area.
• Custom-designed machines that combine mechanical mixing with water jets have proven very effective.
• The weight-bearing capacity of the sediments will determine which types of equipment to use.

Safety notes

• During operation of heavy equipment, a spotter should be present to ensure safe operations.
• Traction of heavy equipment is typically reduced as sediment size increases.
• Operations in flowing water environments may require fast water rescue support personnel.

Overview of tactic consideration(s) for specific conditions

• Flowing Water:
  • Appropriate for containment/recovery areas with minimal to no flow.
• Winter:
  • Appropriate for winter use, if ice conditions allow.
  • If operations are to be completed on ice, an Ice Safety Plan must be prepared and implemented.
• Remote Areas:
  • Consider logistics and waste management/disposal requirements – may be less appropriate as technique requires access for earth-moving equipment.

Objective

• To move oiled materials from one location to another location where there is a higher level of water movement, typically wave energy, that is available to accelerate natural oil removal processes.

Description

• Earth-moving equipment (e.g. front-end loaders, graders, or bulldozers) is used to move the oil or oiled sediments from the surface or subsurface areas where they are protected from natural physical abrasion and weathering processes to locations where these processes are more active, such as the swash zone or active channel margin.
• Sediment relocation differs from mixing techniques as the oiled sediments are physically moved from one location to another as opposed to being agitated in place.
• Oil released from the substrate enters the water column as particulate oil, dispersed oil, or oil-mineral aggregates – the bulk of the oil dissipates in the water column and is not collected.
• Sediment relocation can be combined with manual removal techniques to recover small patches of high-concentration oil uncovered during excavation.

Safety notes

• During operation of heavy equipment, a spotter should be present to ensure safe operations.
• Traction of heavy equipment is typically reduced as sediment size increases.