Ontario Waterpower Development Surface Water Quality and Fish Sampling … · Surface Water Quality and Fish Sampling Programs Figure 1. Intended application of the BMP. 2. Background

BEST MANAGEMENT PRACTICES

Ontario Waterpower Development

Surface Water Quality and

Fish Sampling Programs

Best Management Practices for Ontario Waterpower Development

Surface Water Quality and Fish Sampling Programs

Waterpower Generating Facility Monitoring for Pre-development Conditions and Early Operation

Prepared by: Hutchinson Environmental Sciences Ltd., April 2014


Table of Contents

1. Introduction .................................................................................................................................... 1

2. Background .................................................................................................................................... 2

2.1 Relevance of Monitoring ............................................................................................................... 2

2.2 Possible Changes to Water Quality Following Impoundment .................................................. 2

3. Monitoring Objectives ................................................................................................................... 4

3.1 Before Development ...................................................................................................................... 4

3.2 After Development ......................................................................................................................... 4

4. Methods .......................................................................................................................................... 5

4.1 Water Sampling .............................................................................................................................. 5

4.1.1 Duration .................................................................................................................. 5 4.1.2 Seasonal Sampling ................................................................................................ 5 4.1.3 Locations ................................................................................................................ 5 4.1.4 Analysis .................................................................................................................. 9 4.1.5 Sample Collection ................................................................................................ 10 4.1.6 Quality Assurance and Control ............................................................................ 10

4.2 Fish Samples ................................................................................................................................ 11

4.2.1 Objectives ............................................................................................................ 11 4.2.2 Rationale .............................................................................................................. 11 4.2.3 Targeted Fish ....................................................................................................... 11 4.2.4 Duration ................................................................................................................ 12 4.2.5 Annual Timing of Sample Events ......................................................................... 13 4.2.6 Locations .............................................................................................................. 13 4.2.7 Mercury Analysis .................................................................................................. 14

5. Closing .......................................................................................................................................... 16

6. References .................................................................................................................................... 17

List of Figures

Figure 1. Intended application of the BMP……………………………………………………………………….2

Figure 2. Water quality sample location conceptual scenarios………………………………………………..8

Figure 3. Fish sample location conceptual plan……………………………………………………….……….15


Hutchinson Environmental Sciences Ltd.

WQBMPOWAFinaldocx.docx 1

1. Introduction

This guidance document was prepared to provide the Ontario Waterpower Association (OWA) and its

members with a description of Best Management Practices (BMP) for surface water and mercury-in-fish

assessment programs prepared for waterpower development subject to the Class Environmental

Assessment for Waterpower Projects (Class EA) in the province of Ontario. The guidance is based on

the scientific principles underlying accurate assessment of surface water quality and mercury in fish. The

document is intended to apply to those aspects of a project relevant to MOE’s Permit to Take Water

requirements and does not include the ecological components reviewed by the Ontario Ministry of Natural

Resources (MNR) as part of Lakes and Rivers Improvement Act approvals. This BMP should be read in

conjunction with the OWA’s “Best Management Practices Guide for the Mitigation of Impacts of

Waterpower Facility Construction, 2012” and the Class EA.

The owners or developers of new waterpower generating facilities or those totally redeveloping or

significantly expanding existing facilities should describe the baseline (i.e. existing) surface water quality

and mercury-in-fish conditions in their immediate study area before facility development to establish

reference conditions, meet Class EA expectations and develop informed facility designs. Following

development, the conditions should be monitored to identify facility-related changes vs. natural

environmental variation. The monitoring results can be used by the industry to provide valuable data to

environmental regulators, to support future decision making and to help identify the need for mitigating

action should it be required. OWA wishes to provide a published guidance to waterpower developers so

that they can undertake responsible and science-based assessment programs. The document

distinguishes between those water quality elements which may be affected by the introduction of the

infrastructure itself (i.e. concrete) and those which may change as a result of establishing or enlarging a

permanently inundated area (i.e., headpond).

This BMP does not retroactively apply to existing operating waterpower facilities. The vast majority of

these facilities have been in operation for decades and, in some cases, for more than a century. They

have established water management regimes, and in some cases have existing monitoring protocols, and

as such the recommendations in this document are not intended and should not be construed to apply to

them. The intended application of the BMP is outlined in Figure 1.

Hutchinson Environmental Sciences Ltd. WQBMPOWAFinaldocx.docx 2


Figure 1. Intended application of the BMP.

2. Background 2.1 Relevance of Monitoring

Surface water quality and mercury accumulation in fish tissue may be affected by any waterpower development that impounds water. Water quality and mercury in fish tissue should be monitored before and after facility development to assess if change is occurring as a result of the development, and if the change poses a human health or environmental risk. For example, mercury concentrations are elevated in fish tissue through much of Ontario as a result of atmospheric deposition and natural soil weathering, and an existing condition baseline of mercury concentrations in fish should be established so that post-development concentrations are not mistakenly attributed to the hydropower facility. Conversely, if change is occurring as a result of development, monitoring results provide valuable information on the trend(s) of change relative to baseline conditions and informed responses can be undertaken. The monitoring results from these projects can be used to inform the design and operation of future projects.

2.2 Possible Changes to Water Quality Following Impoundment

Installing or significantly modifying a waterpower facility can create an impoundment of water in a headpond upstream. This can result in physical changes to the existing aquatic/terrestrial environment which may include vertical thermal stratification in the headpond, increased exposure of water to soils, a change in nutrient or metal cycling and concentrations, and/or changes to the fish and invertebrate communities.

Newly impounded water can be exposed to areas of rock, soil and vegetation that have not been historically saturated with water. Impoundment creates both physical and chemical changes to the water as land changes from a terrestrial environment to an aquatic or riparian environment, with nutrients, metals, organic carbon, dissolved and suspended solids potentially being released to the new, overlying aquatic environment. The rate and nature of change from terrestrial soils to stable saturated sediment will affect the rate of release of the materials and will depend on several factors including the type of




terrestrial vegetation, the depth and type of soil saturated, and the depth, duration and fluctuation of the

inundating water.

Typically, following impoundment, water chemistry in a headpond will change quickly and then stabilize

over time. Nutrients, metals, major ions, dissolved organic carbon, dissolved and suspended solids,

conductivity, alkalinity, dissolved oxygen, and temperature may all change as a result of:

Chemical and physical inputs to surface water from the inundated land;

A shift in the aquatic processes of the water in the headpond;

The physical structure of the water in the headpond (e.g., water depth, thermal stratification, surface

area of the headpond and water residence time); and,

Changes due to increased fetch and wind-induced waves.

Changes in water quality may also occur as the impounded water is returned to a river channel

downstream. Increased velocity may suspend sediments and the discharge may alter temperature and

dissolved oxygen, the extent of which will depend on whether the facility intake or dam/weir structures

entrain water at the surface, or below the water’s surface.

Depending on the nature of the area upstream of the development (e.g. type and amount of vegetation,

amount of organic soils) the potential increase of available mercury in surface water can be a particular

concern. Mercury is present naturally in soils and rocks in Ontario and is enhanced by atmospheric

deposition from human sources such as the combustion of fossil fuels. Inundating land with water results

in the partial release of inorganic mercury accumulated in the vegetation and soils (Bodaly et al. 1984,

Hecky et al. 1991). Decomposition of flooded organic matter in soils and vegetation enhances the

methylation of mercury to the bioavailable and toxic form of methyl mercury (Kelly 1997, Montgomery

2000). Mercury and methyl mercury may biomagnify within the food chain and can pose a health concern

to humans and wildlife through fish consumption (Bodaly et al. 1984, Jackson 1988, Hall et al. 2005).

Mercury concentration in fish is a key input criterion to MOE’s Fish Consumption Guidelines.

Mercury concentrations in fish may increase rapidly after impoundment and then decrease and stabilize

in subsequent years. This cycle has been observed in experimental inundation in Ontario (St. Louis et al.

2004), and in hydroelectric projects in Quebec and northern Manitoba where mercury is also present in

the soils and vegetation of impounded areas from natural and anthropogenic sources

(http://www.hydroquebec.com/sustainable-development/documentation/mercure.html). At present,

however, there is a paucity of data and information with respect to the effect on mercury methylation from

small waterpower projects (e.g. less than 50 MW). The OWA is interested in informing the existing body

of knowledge in this regard, in cooperation with its members, academic institutions and regulators. To this

end, an overarching sampling and monitoring program for small waterpower facilities creating new

headponds is proposed.

http://www.hydroquebec.com/sustainable-development/documentation/mercure.html




3. Monitoring Objectives

3.1 Before Development

The pre-development water quality and fish sampling programs:

1) Measure the parameters which indicate the surface water quality in the existing environment and for

human use before a facility is developed to provide a temporal reference upstream, in the area of the

proposed headpond and downstream of a facility (as appropriate for each facility layout); and,

2) Establish an existing pre-development reference of total and methyl mercury in fish tissue upstream,

in the area of the proposed headpond and downstream (as appropriate).

Samples before development provide a temporal bench mark from which to compare results after

development. The comparison is quantified by a spatial real time reference (when one is available) to

factor in natural changes unrelated to hydropower development, as explained below.

3.2 After Development

Post-development programs provide representative samples from upstream of a facility (spatial real-time

reference), within the headpond (if one is present) and downstream, to monitor any effects on water and

fish quality, taking into account natural variation. To the extent practical, data collection procedures

should be consistent pre- and post-development to reduce variation in parameters and simplify analysis.

Post-development sampling results should be compared to existing pre-development conditions to assess

if change has occurred, and the upstream reference should be compared to headpond (if present) and

downstream samples to determine what amount of change is related to the facility vs. natural variation.

The amount of natural vs. facility-related change can be estimated as follows:

Facility Change = (Condition After - Condition

Before) -

After Development (Condition Downstream -

Condition Upstream)

The rate of change can be estimated once three or more years of post-development data have been

collected, by dividing the “facility change” in the simple model above by the time period. Estimating a rate

of change must be done carefully and consider seasonal changes in water quality, fish community

dynamics and inter-annual natural variability, as well as the need for a multi-year record to establish a

meaningful trend, or the results may be misleading or not represent actual environmental changes.

Other nearby activities taking place at the same time as the new waterpower development should be

taken in to account when considering the specific change that may result from the development. These

could include a combination of point-source (e.g., industrial effluent) and non-point source (e.g.,

atmospheric deposition, forest run-off, erosion). It may not in all cases be possible to attribute/apportion

any amount of change to these activities.




4. Methods

4.1 Water Sampling

4.1.1 Duration

Pre-development sampling should be conducted over two years to reduce the variability associated with

one year’s water quality data and provide a more representative baseline.

Post-development water quality samples should be collected in years 1, 2 and 3 of the facility’s operation.

The results should be compared to the existing pre-development results. Should the trend after the final

year of sampling for key factors continue to significantly increase, a subsequent monitoring program

should be developed.

4.1.2 Seasonal Sampling

Water sampling before and after development should be conducted once during each of the three annual

open water flow periods: immediately after the first flush of the spring freshet (April-May), during the

summer low-flow period (August-September) and during the increasing fall flow (October-November).

The intent of seasonal sampling is to establish a multi-year record of each seasonal flow, and the data

should not be pooled across seasons as annual means. Seasonal variability may be greater than annual

variability, and if pooled, seasonal data may indicate false inter-annual trends.

In most Ontario rivers there are notable differences in water quality associated with the three open water

flow periods as observed in the results of the MOE’s Provincial Water Quality Monitoring Network

(PWQMN), a long term water quality monitoring program conducted on many Ontario lakes and rivers. If

available, long term data from a PWQMN monitoring station on the same reach of river as a facility should

be examined to identify seasonal patterns in water quality. Each year, the sampling dates for each period

should be refined by examining the river’s hydrograph, such that each year’s sampling occurs during the

same period on the hydrograph as previous year(s). If the data from one season is highly variable, it may

indicate that the program is not repeatedly sampling the same flow regime or that flows are highly

variable in the project area, and additional seasonal sampling events may be required to gather more

representative data.

The Water Survey of Canada online provides a reliable record of water levels and flows on most Ontario

rivers http://www.wsc.ec.gc.ca/applications/ H2O/graph-eng.cfm.

4.1.3 Locations

Describing water quality requires collecting samples that represent the intended environment. The

location and number of samples collected before and after development must be carefully selected to

factor in conditions that could affect the water quality upstream, within and downstream of a project area.

Flow conditions, the surface area of the river and other factors may be different before and after

development, and the sampling plan may likewise be different. For example, before development a

single sample location may be sufficient to define the water quality in an unobstructed river with no inputs

from wetlands, small tributaries, human influences, etc., but after development, three sample locations

http://www.wsc.ec.gc.ca/applications/%20H2O/grapheng.cfm?station=04LC003&report=daily&data=flow&year=2010




may be required to sample water from the changed environment - upstream of the project, within the

headpond and downstream of all discharges.

Sampling strategies for common scenarios before and after development are presented below.

Waterpower projects are complex, and the scenarios will not apply to all situations - in these cases, the

proponent should consult an environmental professional and develop a sampling plan that collects

representative water samples for their facility.

Before Development

Before development, water quality samples should be collected within the project area (i.e., from

somewhere between the proposed upstream extent of the headpond and the discharge of the power

house tailrace). This assumes that water quality is the same within the project area in an unobstructed

river. Where the project area is not uniform, other strategies should be employed. Four examples of pre-

development water sampling locations are presented to reflect different project environments:

1. One sampling location is adequate for an unobstructed and uniform project area (Figure 2,

Scenario A –page 6).

In some instances and seasons, the project area may not be reasonably accessible and a sample

from the same reach of river as the project may be sufficient. For the purposes of this work, a ‘reach

of river’ is defined as a section of river that is unbroken by features that could appreciably change its

water quality such as major tributaries, large falls that impound water or appreciably slow the river’s

flow, changes in surrounding land type/land use, or human disturbance.

2. A tributary or other influence (e.g. human disturbance such as urban runoff) entering the river within

the project area could affect water quality. In this case, a water sample collected upstream and

downstream of the influence differentiates between the water quality of the river entering the project

area and the combined water quality of the river and the tributary within the project area (Scenario

B).

3. If the headpond provides direct hydraulic connection with an upstream lake or pond, an upstream

sample should be collected from the lake to determine its pre-development water quality

(Scenario C), because lake water quality can be different than the downstream river. If the pond or

lake is thermally stratified, a temperature and dissolved oxygen depth profile should be taken at its

deepest point and water samples collected from each thermal layer. Thermal layers in this

document are defined as the epilimnion (surface), metalimnion (mid), and hypolimnion (bottom).

River water quality can be similarly ‘stratified’ due to temperature, currents and flow path (thalweg).

4. If there is a ponded water or an existing impoundment within the project area, a pre-development

water quality sample should be collected downstream of the pond, within the pond and upstream of it

(Scenario D). If the ponded water is thermally stratified, a temperature and dissolved oxygen depth

profile should be conducted with samples collected from each thermal layer.




After Development

After development water quality samples should be collected as shown at the bottom of Figure 2 and

described below:

Upstream: A water sample immediately upstream of the maximum extent of the headpond. The

upstream reference sample is to assess the quality of the water entering the headpond (upstream of

the transition zone and unaffected by the development). The upstream sample provides a reference

to assess the effects of natural variability on water quality in the project area.

Headpond: A water sample should be collected one meter off of the bottom in the deepest part of the

headpond. In cases where a headpond is thermally stratified, a temperature and dissolved oxygen

profile should be measured, and water samples collected from each thermal layer.

Downstream: A water sample should be collected in the reach of the river within 500 m downstream

of all facility discharges so that project effects can be determined if any exist.




Figure 2. Water quality sample location conceptual scenarios.




4.1.4 Analysis1

Depending on the nature of the development (Figure 1) water quality samples should be analyzed for the

following parameters:

Potential effects associated with the introduction of infrastructure (e.g. concrete):

pH, conductivity, alkalinity;

cations (Mg, Na, Ca, K);

anions (Cl, SO4);

total suspended solids (TSS) and total dissolved solids (TDS); and,

nitrate, nitrite, ammonia and total Kjeldahl nitrogen (TKN).

If rock fill is involved, total metals analysis may also be appropriate.

Potential effects associated with the establishment of a new impoundment:

The parameters listed above, plus:

water temperature;

dissolved oxygen;

dissolved organic carbon (DOC);

total phosphorus;

total metals;

low level total mercury (0.1 ng/L detection limit); and,

low level methyl mercury (0.02 ng/L detection limit).

Water temperature, dissolved oxygen, pH, conductivity and turbidity should be measured in the field with

instruments that are calibrated daily, or on a shorter interval if environmental conditions or instrument

operation require.

1 Some water quality analytical protocols are available from MOE – see references




4.1.5 Sample Collection2

Each water quality sample should be collected as follows:

From greater than 2 m off shore using a clean sampling vessel secured to a clean, contaminant-free

sampling pole;

From the flowing portion of the main channel of the river, avoiding eddies, back pools or floating

debris, since water from these areas may not represent the volume-weighted water quality in the

river;

All samples should be collected during periods when the area has not been affected by short-term

storm flows, as conditions during storm flow are atypical of “normal” river conditions;

Into clean, laboratory supplied bottles containing the appropriate chemical preservative, and stored

on ice or frozen as required. Samples should be field filtered, using laboratory-supplied filters as

required;

All samples, containers and instruments for field measurements should be handled only by personnel

wearing clean, contaminant-free nitrile gloves;

Each sample location should be logged with a GPS;

The date, time and field conditions at the time of sampling (e.g., weather, snow and ice presence)

should be recorded and the sample location photographed; and,

Samples should be shipped to the analytical laboratories with chain of custody documents to record

the sample shipping and handling.

If water samples are collected in lake or headpond where there is minimal water flow, a dissolved oxygen

and temperature profile should be measured, with readings taken at every metre of depth. If the lake or

headpond is thermally stratified, a discrete water quality sample should be collected from the epilimnion

and 1 m off the bottom in the hypolimnion.

4.1.6 Quality Assurance and Control

A duplicate of each sample should be collected approximately 10 minutes after the initial sample to

address the spatial and temporal variance of the flowing river. The duplicate samples shall be collected

from the same location as the initial sample, but represent different water because the river constantly

flows past the sample location.

Analytical results from the sample and its duplicate pair can be compared to assess confidence in sample

representativeness via replication. The blind duplicates should also be used to confirm the accuracy of

the lab’s analytical methods by comparison to the sample. This provides quality assurance data for 100%

2 Some water quality sampling protocols (e.g. Clean Hands/Dirty Hands) are available from MOE – see references




of the samples collected; in a flowing river, this assurance is prudent due to the spatial and temporal

fluctuation in water quality. A lower number of quality assurance samples (e.g., 10% of the total samples

collected) may be sufficient in lakes, headponds or other standing water where there is less variability.

4.2 Fish Samples

4.2.1 Objectives

Large fish potentially used for human consumption and forage fish that are consumed by lower predators

and are indicators of bioaccumulation should be monitored to assess the possible impacts of mercury

bioaccumulation on people and fish-consuming wildlife. All analytical results and physical fish data

should be reported to the OWA annually, and in the case of large fish data, in time for the MOE to include

in its annual Fish Consumption Guidelines. Fish communities should represent: a) the area potentially

impacted by the development - the headpond and downstream; and b) a reference area that will not be

impacted by flooding and is separated by a barrier to fish migration (if this is present).

4.2.2 Rationale

The sampling program for total mercury and methyl mercury in fish considers:

The modes of mercury transport from headponds – i.e., passively by migration with water and/or

suspended solids flowing downstream, and actively in fish body burdens which can move up and

downstream;

Naturally occurring mercury in the environment, and differentiating it from facility-generated mercury

using upstream spatial references, or temporal references where there is no barrier to fish migration

that would isolate an upstream fish population;

The availability of fish for sampling, including where fish are seasonally and the sustainability of

sampling a population of fish several times in the pre- and post-development periods;

The safety of the collectors; and,

The dynamics of mercury uptake and accumulation in fish of different species and ages.

4.2.3 Targeted Fish

The targeted fish species should include large predator fish that are likely to be consumed by anglers and

sustenance fishers, as well as forage fish. The type and availability of fish encountered during pre-

development sampling and the fish that are expected to be present after development should be

considered, as follows:

Large Fish: 20 individuals of at least 25 to 55 cm size from each sampling location; fish species

common to the area that can be sustainably caught in subsequent years; piscivorous fish are

preferred as they are the greatest accumulator of mercury, but if they are not available benthivorous

or omnivorous fish may be a suitable substitute with scientifically defensible rationale. The fish




caught at each location and across the project area should all be of the same species for a consistent

sample pool.

Forage Fish: at each sample site, five (5) composite samples of 5 to 10 individuals of either a) young

of the year (YOY) Yellow Perch (Perca flavescens), b) yearling Yellow Perch or c) another

sustainably available forage species, to provide a composite of 10 grams for each sample. The fish

should be of the same species at each location and across the project area.

The availability of fish following development should be considered at the onset of a program, to ensure

that a consistent data set is built before and after development. If appreciable flows or habitat changes

are expected, fish should be collected that are likely to be present in the new habitats.

In some rivers there may not be sufficient fish populations to meet the recommended catch. In these

cases, the proponent should present a detailed description of the fish sampling programs conducted,

including the methods and effort expended, and provide rationale for why it has been concluded that the

fish population insufficient or unsustainable. The statistical power of low-number catches to provide

meaningful comparisons should also be discussed.

Large fish sampling is described in the MOE’s Sport Fish Contaminant Monitoring Program, “Protocol for

the Collection of Sport Fish Samples for Inorganic and Organic Contaminant Analyses”. Forage fish

sampling should be conducted in a manner that collects representative samples, limits mercury cross-

contamination and meets the analytical laboratory’s requirements. The Ontario Ministry of Natural

Resources (MNR) “Riverine Index Netting” (RIN) Protocol and various “Lake Index Netting” protocols are

excellent references. All fish should be aged, weighed, have total or fork length measured (as applicable)

and gender recorded, and relationships should be established between these variables and mercury

content. Scientifically equivalent protocols to MOE and MNR’s may be developed by the proponent.

The fish collection described requires a Licence to Collect Fish for Scientific Purposes from the MNR

issued under the Fish and Wildlife Conservation Act.

4.2.4 Duration

Pre-development fish sampling should occur as close to the completion of the Environmental Report as

possible recognizing that it may take two or more years to catch a sufficient number of large fish.

After development, forage fish should be sampled during each of years 1, 2, 3, 6 and 9. The sampling

interval reflects the intent of using forage fish as an ‘early warning’ of mercury bioaccumulation in the food

chain at their lower trophic level relative to large fish, and tendency to accumulate environmental mercury

in a shorter timeframe. Sampling in later years monitors the mercury trend as the system stabilizes.

Large fish should be sampled in years 3, 6 and 9 following development reflecting the observed

accumulation rate of mercury in their trophic level following water impoundment in experimental and other

impoundments.




In either case, should the mercury trend in the final year of sampling continue to significantly increase

indicating that peak mercury concentrations have not been reached, a subsequent monitoring program

should be developed.

4.2.5 Annual Timing of Sample Events

The relative sizes of forage fish increase quickly over the course of one year and sampling should be

conducted during most likely time of year to catch similarly fish that are similar species, age and size as

the pre-development samples, and prevent the need for additional sampling in the same year. In many

cases, this will be the summer flow regime when YOY may be large enough to catch, fish are likely to be

resident in the area, yearling fish are active and before waters cool.

Larger fish can be sampled over multiple visits in a single season as required to achieve the

recommended catch, or even over two to three years, provided that a comparable size and distribution of

fish are analyzed from each sampling event.

4.2.6 Locations

Before Development

The locations where fish should be sampled will depend on the barriers to fish migration on the reach of

river where a facility is to be located and the size of the project area. Ideally, fish should be sampled

upstream, in the proposed headpond area and downstream of a proposed facility. For large fish, this

requires a naturally occurring barrier to upstream fish migration at the facility location and at the upstream

extend of the headpond to segregate populations. Forage fish populations may be segregated by a

distance appropriate to the typical migration of the species to be sampled; forage fish typically do not

migrate long distances. If available in the project area, forage fish should be sampled in areas with

different environmental conditions such as near areas of organic enrichment, gravel bars and back

eddies, providing these habitats will also be present following development to yield sufficient post-

development fish samples.

If a barrier to upstream fish migration exists within the project area before development, fish may migrate

downstream through it but cannot migrate back upstream. Barriers may cause some populations of fish

to be isolated in upstream areas which will be influenced by the development.

If no barrier to fish migration exists prior to development, fish captured upstream of a facility could move

downstream of it and vice-versa. Therefore, if there is no barrier, pre-development fish sampling should

focus on locations within the project area where the highest catches of fish are expected. There is no

need to separate upstream from downstream sites in this case, however care must be taken to collect

representative forage fish throughout the project area that would not be isolated by distance.

The river conditions that govern fish population segregation are complex, and rationale should be

provided with sample results to explain the sampling program.




After Development

After development, fish should be sampled in the following locations, within the same reach of the river as

the facility:

Upstream (reference): In cases where there is barrier to fish migration upstream of the facility and

within the same reach of the river, fish sampling should be conducted upstream of the barrier to

provide a spatial reference. The upstream reference will also assess the natural variability of

mercury in fish in the project area as it contains fish unaffected by the facility. If there is no upstream

reference for a facility, it may not be possible to factor natural variability into post-development

changes if they are observed;

Headpond (if present): These fish are most likely to be exposed to any mercury increases in water or

the food chain resulting from water impoundment, and fish should be sampled sufficiently to

represent the entire headpond area; and,

Downstream: Fish sampling should be conducted downstream of each proposed facility to monitor

the effects of mercury generated in the impoundment area (if any) on downstream fish. In some

cases the water retention structure(s) at each facility will be an impassable barrier to fish moving

upstream, but fish may migrate downstream and the mercury concentrations in fish below a facility

may represent:

a) Fish that have migrated downstream from the headpond;

b) Fish that inhabit the area where they have been collected immediately downstream of the

proposed facility and are affected by changes in water quality, detritus and food migrating

downstream from the headpond;

c) Fish that have foraged in a different reach of the river than the facility (downstream),

including adjoining tributaries, and have accumulated mercury in these areas that is

unrelated to the facility; or,

d) A combination of the above.

Site conditions should be carefully considered when interpreting post-development fish sample results to

differentiate between the effects of impoundment, and the conditions of fish that have never been

exposed to the headpond but have been collected downstream of the facility. Figure 3 on the following

page shows a conceptual pre- and post-development fish sampling plan.

4.2.7 Mercury Analysis

Large Fish

Large fish should be analyzed for total mercury with a detection limit of < 2.0 ng/g. Only fillets should be

analyzed as described in the MOE Sport Fish Contaminant Monitoring Program Protocol. Most mercury

in fish is the more toxic form of methyl mercury (Rodgers et al, 1982) which is accounted for in total




mercury measurements. For the purpose of setting fish consumption guidelines and assessing the

toxicity of mercury in fish, it is conservatively assumed that all mercury measured in fish is methylated.

Forage Fish

Forage fish samples should be analyzed for methyl mercury (detection limit of <1.0 ng/g) and total

mercury (detection limit < 2.0 ng/g) to establish the proportion of methyl mercury in total and track

bioaccumulation processes. Forage fish analysis should be conducted on whole fish composites,

reflecting the intent to assess foragers for total and methyl mercury body burdens in the food chain, and

since forage fish are commonly consumed whole by predators.

Figure 3. Fish sample location conceptual plan.




5. Closing

This guidance document has been prepared to provide the OWA and its members with information on

water quality and mercury-in-fish sampling programs to assess the early operation effects of new

waterpower developments in Ontario. It is not intended to be a standalone document and should be read

and applied, where appropriate, as a component of the “Best Management Practices Guide for the

Mitigation of Impacts of Waterpower Facility Construction, 2012”. Its use should complement and not

replace the professional judgement of the proponent’s environmental practitioners.




6. References

Bodaly, We A., R. E. Hecky, and W. J. P. Fudge. 1984. Increases in fish mercury levels in lakes flooded

by the Churchill River diversion, northern Manitoba. Canadian Journal of Fisheries and Aquatic

Sciences. 41: 682-691.

Hall BD, St. Louis VL, Rolfhus KR, Bodaly RA, Beaty KG, Paterson M. 2005. The impact of reservoir

creation on the biogeochemical cycling of methyl and total mercury in boreal upland forests.

Ecosystems 2005; 8(3): 248 – 66.

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Ontario Waterpower Development Surface Water Quality and Fish Sampling … · Surface Water Quality and Fish Sampling Programs Figure 1. Intended application of the BMP. 2. Background