Municipality of North CowichanQuamichan Lake Water Quality Task Force

AGENDA

Thursday, May 25, 2017, 4:00 p.m.Municipal Hall - Council Chambers

Pages

1. CALL TO ORDER

2. APPROVAL OF AGENDA

Recommendation:That the Committee approve the agenda as circulated [or as amended].

3. ADOPTION OF MINUTES 3 - 4

Recommendation:That the Committee adopt the minutes of the meeting held March 16, 2017.

4. BUSINESS

4.1 Ground Water

Purpose: To hear from Paul Slade regarding ground water and the potential foraugmentation to surface water bodies.

4.2 Cowichan River Aquifer 

Purpose to hear from Paul Slade on the Cowichan river aquifer and surfacewater interaction study.

4.3 Natural Processes for the Reduction of Runoff

Purpose: To hear from David Polster on how natural systems of runoff controlcan be applied to human endeavours.

4.4 Task Force Report 5 - 35

Purpose: To review the Task Force report regarding the Quamichan Lake.

4.5 Permanent Information Signs

Purpose: To discuss whether to install permanent information signs around theQuamichan Lake.

4.6 Mouth of Quamichan Creek

Purpose: To review the report (to be distributed at the meeting) from theDirector of Engineering and Operations regarding options to improve themouth of Quamichan creek (requested at the March 16th meeting).

4.7 Monitoring Programs

Purpose: To discuss suggest monitoring program details and what needs to bedone for implementation.

4.8 Next Steps

Purpose: To discuss the next step to control nutrients flowing into theQuamichan Lake.

5. NEW BUSINESS

6. ADJOURNMENT

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1

Municipality of North Cowichan

Quamichan Lake Water Quality Task Force

MINUTES

March 16, 2017, 6:00 p.m.

Municipal Hall - Council Chambers

Members Present Mayor Jon Lefebure, Chair

James Cosh

Dave Groves

Tim Kulchyski

Tom Rutherford

Jen Woike

Members Absent Ken Ashley

Staff Present David Conway, Director of Engineering and Operations

Mary Beth MacKenzie, Recording Secretary

1. CALL TO ORDER

There being a quorum present, the Chair called the meeting to order at 6:00 p.m.

2. APPROVAL OF AGENDA

It was moved and seconded:

That the Committee approve the agenda as amended to add 5.1 Limiting Nutrients Entering

Quamichan Lake.

CARRIED

3. ADOPTION OF MINUTES

It was moved and seconded:

That the Committee adopt the minutes of the meetings held January 19, 2017 and February 9,

2017.

CARRIED

4. BUSINESS

4.1 Nutrient Removal

The Committee reviewed a spreadsheet prepared by James Cosh providing a

comprehensive list of mechanical and biological treatment actions to improve

Quamichan Lake water quality discussed by the Committee to date. It was noted that

improvements to the outflow should also be considered as an option to improve the

flushing of nutrients from the lake, and that any actions taken should be low risk, cost-

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March 16, 2017 - Quamichan Lake Water Quality Task Force

2

effective and assessable. After discussing the pros and cons of the various treatment

actions, the Committee agreed to further investigate a) skimming algae bloom;

b) digester bacteria (concentrated bacteriological cultures); c) barley straw; d) zeolite;

e) cold water; and f) improved outflow.

It was moved and seconded:

That the Director of Engineering and Operations prepare a report reviewing options to

improve the mouth of Quamichan creek, including an application under Section 11 of the

Water Sustainability Act, if necessary.

CARRIED

4.2 Monitoring Program

The Committee discussed the preparation of a monitoring program for presentation to

Council, noting the need for a sampling design. James Cosh, Dave Groves and Tom

Rutherford agreed to discuss this matter with Deb Epps of the Ministry of Environment

and Stacy Sowa of Island Health.

4.3 Posted Signs

Responding to a question by the Committee, the Director of Engineering and Operations

advised that the Municipality posts signs when there are elevated toxicity levels in

Quamichan Lake, and has a responsibility to remove the signs when the conditions cease

to exist. He also noted that a protocol used by the Capital Regional District may be of

interest, and offered to send it to Committee members following the meeting.

5. NEW BUSINESS

5.1 Limiting Nutrients Entering Quamichan Lake

The Committee agreed to discuss at a future meeting, options to limit nutrients entering

Quamichan Lake including the use of barley straw at lake inlets. Pilot projects of barley

straw application to streams and zeolite applications either to streams or ponds on

private property were suggested. Members of the public in attendance at the meeting

offered the use of their properties to conduct the pilot project as well as volunteering to

help with the work.

6. ADJOURNMENT

The meeting ended at 8:23 p.m.

___________________________________________ _____________________________________

Signed by Chair or Member Presiding Certified by Recording Secretary

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Municipality of North Cowichan

Quamichan Lake Water Quality Task Force

December 2016

1. THE PROBLEM

1.1. Description of Quamichan Lake

All of the following is taken from the phosphorus loading study done in 2008.

Quamichan Watershed Profile

The watershed profile provides key characteristics required to inform an understanding of

the recommended goals, objective and actions of the Management Plan. The watershed

occupies part of a relatively flat lowland area formed by glacial infilling and is surrounded by

steep bedrock structures including Mount Tzouhalem to the east, Maple Mountain and Mount

Richards to the north, and Mount Prevost to the west beyond Somenos Lake. The Somenos

aquifer is approximately 46 km in size and includes Somenos and Quamichan Lakes.

Watershed characteristics

Drainage basin is approximately 17.33 sq. km

Approximately 15 surface inlets into Quamichan Lake

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One major outlet located at Quamichan Creek discharges into Cowichan River 1.6 km south

of the lake.

McIntyre Creek drains the low lying wetlands at the northeast

Quamichan Watershed Boundary

Quamichan Watershed Management Plan ii end of the lake Quamichan Lake, the largest of

three lakes in the District of North Cowichan, is defined by shallow bedrock at the margins.

Lake surface area is 3.13 sq. km

Length is 3.1 km and width is 1.2 km

Orientation is a northeast-southwest direction

Lake elevation is approximately 25.45 metres (83.50 feet) geodetic

Quamichan Creek discharges into the river at approximately 5.20 meters (17 feet)

Mean depth is 4.7 meters (15.42 feet)

Maximum depth is 7.9 meters (25.92 feet)

Lake drops off relatively quickly to around the 3.04 meters (10 feet), within 25 to 50 feet off

the shore line.

Water Quality

Quamichan Lake is classified as mesotrophic-eutrophic (nutrient rich). This means the lake has

abundant plant life, including algae, due to higher nutrient levels. The primary nutrient of

concern is phosphorus. A recent nutrient budget found:

55% of the current phosphorus load comes from surface run-off

30% of the nutrient is internally generated from lake sediment

15% of the phosphorus load comes from aerial deposition

Twenty-seven percent (27%) of the total phosphorus input to the lake flows out of the

lake annually. The remaining 73% stays in the lake and is deposited in the sediments. The

nutrient level in the lake will continue to increase with the continued pressure from

residential, agriculture and development impacts, and to some degree from internal

nutrient loading.

Lake Water Hydrology

The lake level average annual range is 1.0 metre (3.2 feet) to 1.22 meters (4 feet). In severe

winter years it has been recorded as high as 1.58 meters (5 feet). Flows out of Quamichan Lake

are controlled by the first 310 metres of Quamichan Creek. The lake drops below the outlet level

around early August and Quamichan Creek stays dry until the heavy rains in fall. The flood plain

to the north of Quamichan Lake is comprised of 178 acres affecting 19 parcels of land.

The majority of which are used for agricultural productivity

Wetlands are drained by McIntyre Creek

Significant blockages in the first 310 metres of Quamichan Creek can hold spring water

levels high and can contribute to flooding of lands along McIntyre Creek Quamichan

Watershed Management Plan iii Agricultural production in these low-lying lands is primarily

silage corn or silage grain

Crops require mid-May planting and are normally harvested between late August and late

September

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If fields are not harvested, which can occur when the summer water level is too high for

machine entry, nutrients that are captured are subsequently released back to the

watercourse

The breakdown of this organic matter also creates a biological oxygen demand Reed canary

grasses grown along McIntyre Creek needs to be harvest in early summer

Reed Canary Grass represents a significant nutrient trap, and thus removal of the hay

provides a significant net nutrient removal

Lake Level

Agricultural landowners identified an

agriculturally compatible lake level for

mid-May of approximately -76.2 cm (-30

inches) below the top of the Art Mann

Park concrete wall which is equivalent to

an elevation of 25.58 metres.

At the target elevation farmers in the

McIntyre Creek area can then rely on

evaporation to reduce remaining water

content and thus to optimize crop

production on the lowest area

(From Quamichan Watershed Management

Plan)

1.1.2 Nutrient loading

LAKE HISTORY

Quamichan Lake is a large, but shallow lake located on Southern Vancouver Island, in Duncan,

B.C. It is a recreational lake, used for activities such as boating and swimming, and is an

important habitat for fish and other aquatic life. Quamichan Lake has experienced deteriorating

water quality over the last 60 years (McPherson, 2006), and is currently classified as a

mesotrophic-eutrophic lake. This classification means that there is an abundance of nutrients in

the lake enabling excess plant growth in the lake. This plant growth is primarily in the form of

phytoplankton; unicellular photosynthetic life that grows within the surface layer of water

column. When plant growth is enhanced by nutrient inputs into the lake, there are several

ensuing adverse effects on the quality of the lake. First of all, photosynthetic growth appears at

the surface of the lake as thick suspended green particles, resembling murky pea soup, making

the lake aesthetically undesirable for recreational activities such as swimming and boating. A

second adverse affect of enhanced photosynthetic growth in the lake, is the subsequent

depletion of oxygen. When the algae at the surface die, they sink to depths, and consume

oxygen as part of the decomposition process. Oxygen can be sufficiently depleted through this

process to create an anoxic, or near anoxic environment at depth, inhospitable to fish seeking

refuge from warmer surface temperatures. Therefore, lake eutrophication, such as in Quamichan

Lake, can result in massive fish kills.

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4

Rainfall flushes excess phosphorus and other elements from the surrounding lands of the

Quamichan Lake watershed, feeding surface flow in the form of several small streams and

ditches, into Quamichan Lake. Different types of land use, such as agriculture, hobby farms, or

compact residential areas, are associated with different amounts of phosphorus contributions to

surface water run-off. For example, fertilized agricultural fields typically have higher nutrient

concentration run-off, than a fallow, un-utilized pasture area. Subsurface water flow through

unsaturated ground will also draw nutrients into the lake. Of concern in this case, would be

areas of aging or failing septic fields. Both surface and subsurface flow present external sources

of phosphorus to the lake.

There are also internal sources of phosphorus from within the lake which can also be a

significant nutrient source. In oxic conditions, phosphorus is bound to metals (iron, aluminum,

manganese, calcium, etc.) in lake bottom sediments. But when conditions become anoxic and

reducing (dissolved oxygen less than 1mg/L), the phosphorus is released from the metal

complex into the water column. Therefore, phosphorus and metal concentrations are highest at

an anoxic sediment-water interface. Mixing of the shallow lake brings phosphorus released from

sediments to the surface where it can be utilized by photosynthetic organisms. Over time,

phosphorus will build up in the sediments from continuous deposition, sinking of dead surface

biomass, and pro-longed eutrophication of the lake, as is the case with Quamichan Lake

PHOSPHORUS HISTORY AT QUAMICHAN LAKE

Between 1985 and 2005, the average total phosphorus in Quamichan Lake was .06mgl, ranging

between 5-255ug/L. The Criteria for Drinking Water and Recreation is 10 ug/L maximum. During

this period, 60/66 (90%) of samples during this period exceeded the criteria, 83% (55/66)

exceeded the upper limit of the Aquatic Life Maximum criteria and 98% (65/66) exceeded the

lower limit of Aquatic Life Maximum criteria (McPherson, 2006). Total phosphorus

concentrations peak from mid September to mid October at which point fall turnover and

increased run-off mix the lake and hopefully some of the nutrients are flushed from the lake.

SUMMARY OF INPUT STREAMS

The Quamichan Lake drainage basin is estimated to be 1707.98 hectares (personal. comment.,

Brent Nielsen, North Cowichan Regional District). The surface area of Quamichan Lake

constitutes 313 ha (www.fishwizard.com). The Quamichan Lake watershed (Figure 1) intersects

1727 parcels of land in the North Cowichan Municipal District, 1525 of which are designated

Residential, and 181 of which are designated Agricultural. Of all the parcels, there are 127 land

parcels with a waterfront boundary. The East side of the lake is predominantly urban, with more

recent residential developments. It is also much steeper than the north and west sides, which are

typically more rural, with many agricultural properties, and smaller hobby farm-type lands.

Numerous small ditches and creeks, running through culverts and various properties constitute

the main surface water inputs to Quamichan Lake. Jim Cosh and Per Dahlstrom, volunteers from

the Quamichan Watershed Stewardship Committee familiar with the area, identified a total of 15

stream sites in 2006 and 2007 to be sampled. These stream inputs into Quamichan Lake are

seasonal, characterized by low flow, with peak flow in winter months, and very little or no flow

between late spring and October/November. Stream inputs were sampled during the rainy

season, and after the lake’s fall turnover, which typically occurs by mid-October (McPherson,

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5

2006). The advantage to sampling intake streams at the beginning of the rainy season is that

nutrient loading signals from the surrounding land use areas will be amplified by increased

runoff, but not yet diluted, as they will be further into the rainy season.

Twelve stream sites, which feed Quamichan Lake, were sampled after heavy rainfall events in fall

2006. Thirteen stream sites, and Quamichan Creek, the lake’s outflow, were sampled after heavy

rainfall events in fall 2007. All samples were measured for total phosphorus concentration. In

2007, stream velocity and depth were also measured using a SWOFFER current meter. Inflow

stream sites ranged between 1.5- 24.4cm deep and 0.3-1.5m wide (wetted), averaging 6.6cm

deep and 74cm wide (wetted) in 2007. Quamichan Creek, the lake’s outflow stream was much

wider, and measured 2 metres, then 4 metres wide (wetted width), 3 weeks later. On both

occasions, the outflow was too fast flowing to safely measure a full depth-velocity stream

profile. Instead, two depth/flow measurements were taken safely from the bank of the creek.

Figure 1. Quamichan Lake Watershed Boundary (provided by Bent Nielsen of the Municipality

of North Cowichan), and sampled stream locations: 1=MacIntyre Creek; 1a=MacIntyre Creek at

Herd Rd; 2=1950 Stanhope Rd; 3=Garth Creek Pumphouse; 4=Sterling Creek; 5=Churchill Creek;

6=Deykin Creek; 7=Woodgrove Creek; 7a=South Woodgrove Creek; 8=Highwood Creek;

9=Aitken Creek; 10=1840 Stamps Rd; 11=Martin Place; 12=Stanhope Creek; 13=Osprey Creek;

14=Trumpeter Point; 15=Quamichan Creek (outflow).

1

2,12

3

4

5

6

7 7a

8

9

10

11

13

15

14

1a

9

6

Runoff proportion, the amount of precipitation reaching the land that will run off the land into

creeks and lakes, was estimated using a standard value of 48.4% (Sprague, 2007). Given the

similarity in geology and surficial bedrock type between Quamichan Lake and Cusheon Lake of

Saltspring Island (Geological Survey of Canada, 1965 & 1980), this is a reasonable

approximation. Most of the Quamichan Lake drainage basin is underlain by Quaternary period

formations, consisting of sand, gravel, silt and clay (the Capilano Sediment formation). Smaller

portions of the drainage basin, on the east side of the lake, are underlain by older upper

Cretaceous period shale, siltstone, sandstone, conglomerate formations. The Cusheon Lake

drainage basin on Saltspring Island is also underlain by these same shale, siltstone, sandstone,

conglomerate formations. Quamichan Lake basin surficial bedrock consists of predominantly silt,

clay, stony clay and till-like mixtures, thicknesses up to 75 feet, as does the Cusheon Lake

drainage basin.

Evaporation is estimated at 0.713 metres per year, again based on values used in models of

nearby Cusheon Lake (Sprague, 2007).

From these estimates for annual evaporation and surface runoff proportions in the watershed,

and a value of 1.36m precipitation falling in the watershed (Environment Canada, 2007), a

theoretical water balance budget for the lake can be calculated. Inputs to the lake include

surface runoff from the watershed (48.4% x 1395ha (area of watershed not including lake

surface) x 1.36m precipitation), and precipitation directly on the surface of the lake (1.36m x

313ha). Therefore, these two water sources contribute 9,182,000m3 and 4,257,000m3 of water,

respectively, into Quamichan lake, for a total of 13,439,000m3 annually. Evaporation from the

lake surface removes 2,231,690m3 (0.713x313ha) of the water from the lake (17%). Therefore,

assuming a steady state over a year’s period, the remaining percentage (83%) is outflow from

the lake, and is estimated at 11,207,558m3 per year. From this simple water budget calculation,

the water residence time (flushing rate) for Quamichan Lake is estimated to be 1.02 years,

meaning that the entire volume of the lake is effectively replaced by inflowing water every 1.02

years. The slower residence time means that water is retained in the lake over the course of a

year, allowing nutrients to accumulate in the lake.

SURFACE WATER PHOSPHORUS LOADING DATA

Table 1 below summarizes the total phosphorus concentrations from the 2006 and 2007

Quamichan Lake inflow/outflow stream sampling. Figure 2 illustrates that in both sampling

years, total phosphorus concentration has been consistently higher in the creeks draining

agricultural and rural areas. Calculations of total phosphorus loading, based on phosphorus

concentrations and flow volumes (Figure 3), also show a higher loading from creeks draining

agricultural/rural land, as well as peaks at two stream sites draining residential areas (#7a South

Woodgrove Creek, and #9 Aitken Creek). Other residential sites have relatively low total

phosphorus loadings.

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Table 1. Phosphorus concentration (mg/L) of Quamichan Lake inflow and outflow streams, as

sampled in fall of 2006 and 2007.

Site # Site Description

2006-11-05 2006-11-16 2007-11-13&14 2007-12-05

Quamichan Lake Inflows 1 Macintyre Creek 1.56 0.002 not sampled not sampled

2 1950 Stanhope Rd. 0.087 0.061 not sampled not sampled

3 Garth Creek Pumphouse 0.012 0.004 0.039 0.03

4 Sterling Creek 0.01 <0.002 0.017 0.02

5 Churchill Creek 0.011 0.003 0.04 0.022

6 Deykin Creek 0.05 0.003 0.017 0.02

7 Woodgrove Creek 0.009 <0.002 0.007 0.007

7a South Woodgrove Creek not sampled 0.018

8 Highwood Creek 0.029 <0.002 0.009 0.008

9 Aitken Creek 0.015 <0.002 0.014 0.02

10 1840 Stamps Rd 0.205 0.201 0.78 1.26

11 Martin Place 0.097 0.004 0.096 0.125

12 Stanhope Creek <0.002 0.004 0.049 0.071

13 Osprey Creek 0.015 0.003 0.018 0.011

14 Trumpeter 0.016 0.023

Sum of Inflows 2.101 0.293 1.102 1.635

Quamichan Lake Outflow 15 Quamichan Creek 0.145 0.059

Total Phosphorus (mg/L)

(RDL = 0.002)

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Figure 2: Phosphorus concentration (mg/L) of surface flow streams feeding Quamichan Lake.

Figure 3: Total phosphorus loadings (kg/day) from surface flow streams feeding Quamichan

Lake. See Appendix A for data.

Phosphorus Concentration of Surface inflows to Quamichan Lake

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

MacIn

tyre

Cre

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1950

Sta

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1840

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Mart

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Sta

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Cre

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Ste

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Cre

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Deykin

Cre

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Woodgro

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Cre

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South

Woodgro

ve

Hig

hw

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Cre

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Aitken C

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Ospre

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Cre

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Tru

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Poin

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Quam

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Cre

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1 2 10 11 12 3 4 5 6 7 7a 8 9 13 14 15

Agricultural/Rural Residential Outlet

Stream

Phosphoru

s C

oncentr

ation (

mg/L

)

November 5th, 2006

November 16th, 2006

November 13/14, 2007

December 5th, 2007

1.5

6

1.2

6

Surface Phosphorus Loading to Quamichan Lake

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

18

40

Sta

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Ma

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Sta

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Ga

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10 11 12 3 4 5 6 7 7a 8 9 13 14 15

Agricultural/Rural Residential Outlet

Stream

Ma

ss o

f P

ho

sp

ho

rus (

kg

/da

y)

November 13/14th, 2007

December 5th, 2007

1.9

6

kg/d

ay

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The two creeks with higher phosphorus loadings that are draining residential areas are located

on the more northern end of the lake’s east-side. Portions of this north-western developed area

of the watershed are currently still on septic, but have plans to be switched over to sewer in the

near future (personal communication, Glen Andison, engineering technician at the District of

North Cowichan, 2007). Therefore, it is suspected this may be a contributing factor behind the

high phosphorus loadings at these two sites. Switching the area to sewer could potentially

reduce this phosphorus source, and should be monitored after sewage connection for

confirmation.

MacIntyre Creek, the creek identified on most maps as the main inflow to Quamichan Lake, was

not sampled in 2007 because there was no identifiable, single distinguished main stream

channel. Close to the lake (access via a property at the end of Stamps Rd.), the creek had many

braided channels through a flooded, grassy field. It was observed that there would be too much

influence from lake levels here at the time of sampling. Higher up on the creek, off Herd Rd,

there was also no visible, flowing channel to sample.

The 2007 data shows that the major surface source of phosphorus to the lake is from the

agricultural/rural area land area along the northern side of the lake. Loadings were higher in the

second sampling December 5th (2007) than the first sampling on November 13/14, 2007, for all

stream sites except one, Osprey Creek (#13). Increasing phosphorus concentrations of inflow

streams as precipitation continues through the winter season is characteristic of a developed

watershed (Nordin et al., 1983). To calculate an annual phosphorus loading from streams, this

report tried different estimates for the number of days the stream had flowing water, and

different values for stream concentration, to give a range of probable loadings from surface

inflow streams, as reported in Table 2.

Table 2: Phosphorus loading of Quamichan Lake from surface inflow streams. See Appendix B

for detailed breakdown of loadings per individual creek. Only 2007 data was used in these

calculations, as no quantitative flow data was collected in 2006.

LOWER

ESTIMATE

UPPER

ESTIMATE

MID

ESTIMATE

# of stream flow days 105 166 120

Agricultural/Rural 0.4185 1.8040 1.1115

Residential 0.1983 0.7231 0.4607

Output 0.2540 1.9565 1.1052

Agricultural/Rural 43.9 299.5 133.4

Residential 20.8 120.0 55.3

TOTAL Inflow 64.8 419.6 188.7

Output 26.7 324.8 132.6

Loading concentration

(kg/day)*

Annual loading

(kg/year)

*Nov 13/14, 2007 loading data used for lower estimate; Dec 5, 2007 loading data used for upper estimate; An

average of November and December sampling days’ data used for the mid estimate.

Table 5. Quamichan Lake phosphorus budget estimate, based on 120 days per year of flowing

water in the inflow creeks, and a 99.65 – 121.05kg internal load (calculated with different

methods).

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(From Phosphorus Loading Study for Quamichan Lake in Duncan BC by Meara Crawford – BC

Ministry of Environment 2008)

1.2. Algae

1.2.1. Cyanobacteria - cyanobacteria are bacteria that share features of both bacteria

and algae. They are similar to algae in size, possess blue-green pigmentation

and are capable of photosynthesis; thus, they are often termed blue-green algae

(WHO, 2003a). Most planktonic cyanobacteria, including the species found in

Canadian lakes, form colonies, which can appear as irregular groupings of cells

or as filamentous chains that can be straight, coiled or branched (Chorus and

Bartram, 1999; Falconer, 2005). In a typical summer, a lake water sample can

contain several species of cyanobacteria, along with numerous other species of

algae. Cyanobacterial cells contain small gas bubbles called vacuoles, which

allow them to control their buoyancy. The cells use this buoyancy control to

move up in the water column to where light is the greatest and down in the

water column to where nutrients are more abundant (Falconer, 2005). In still,

stratified surface waters, cyanobacteria effectively use the light and nutrients to

proliferate intensively, creating a visible discoloration known as cyanobacterial

blooms (Chorus and Bartram, 1999; Falconer, 2005). These blooms can be very

dense and can have the appearance of being gelatinous or resemble a

collection of fine grass clippings or appear as a homogeneous, soupy mass, as if

green paint has been spilled into the water (WHO, 2003a; Falconer, 2005).

Surface blooms or scums can occur when the cells develop excess buoyancy and

the water is calm enough to let them float to the surface. This excess buoyancy

develops when turbulence (e.g., during storms) sends the cells too deep, during

the hours of darkness, under carbon dioxide-limiting conditions, when the

population is at the end of the growth cycle or any combination of these factors.

Offshore winds may then drive these scums towards the shore where they can

accumulate (Chorus and Bartram, 1999; Falconer, 2005). In this manner,

cyanobacterial blooms may increase their density by a factor of 1000 or more in

a very short period of time (Chorus et al., 2000).

(From Government of Canada Guidelines on Algae)

1.3. Toxins

Cyanobacterial toxins - Cyanobacterial blooms are considered a public health concern

because direct contact with a bloom can cause allergenic-like reactions; and some

cyanobacterial species can produce toxins that may have harmful effects on humans

Source Load (kg/yr) % of Total Input

Internal Loading 99.7 - 121.1 29.5 - 33.7

Streams 188.7 52.5 - 55.8

Agricultural/Rural Streams 133.4 37.1 - 39.3

Residential Streams 55.3 15.4 - 16.3

Aerial Load 49.8 13.9 - 14.7

TOTAL INPUT 338.2 - 359.6

Outflow 132.6

Phosphorus deposited to sediments

(kg/year)

(input minus output)

205.6 - 227

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(Chorus and Bartram, 1999). Over 46 species of cyanobacteria are capable of producing

toxins (Sivonen and Jones, 1999). The most common toxin-producing genera in fresh

water are Anabaena, Aphanizomenon, Cylindrospermopsis, Microcystis, Nodularia and

Planktothrix (syn. Oscillatoria) (Falconer, 2005). Although the conditions leading to the

development of a bloom are relatively well known, the factors responsible for the

dominance of toxin-producing strains are not completely understood (Chorus and

Bartram, 1999; Falconer, 2005). Consequently, toxin formation from cyanobacteria is

even less predictable than the cyanobacterial blooms themselves. Lakes that have never

had a problem can suddenly develop blooms that may contain toxins. Conversely, lakes

that have shown toxic blooms in the past may never show it again. It has been

suggested that worldwide, an average of 60% of the cyanobacterial bloom samples

investigated have been positive for cyanobacterial toxins (range, 10-90%) (Chorus et al.,

2000; WHO, 2003a). As a result, any bloom encountered should be treated as

potentially toxic. Cyanobacterial toxins for the most part are associated with the

cyanobacterial cells--either bound within membranes or occurring freely within the

cells. Toxin release to the surrounding waters can occur as the cells die or are damaged

and leak their contents (Chorus and Bartram, 1999). The bulk of the toxicity, if present,

generally lasts as long as the bloom; however, some toxin may still persist for a short

period after the bloom is gone (Chorus and Bartram, 1999; Falconer, 2005).

Subsequently, contact with waters in which a bloom has developed should be avoided

until it can be unequivocally determined that there is not a risk of contact with

cyanobacterial toxins. The time of toxin persistence can depend on factors such as the

concentration before the bloom's disappearance, and the efficiency of degradation by

natural microbial populations in the water (Falconer, 2005).

(From Government of Canada Guidelines on Algae)

2. WATER QUALITY MONITORING

2.1. The Government of Canada has issued Guidelines for the monitoring of Cyanobacteria

and their toxins. Their guideline values are quoted below:

Guideline values

The recommended guideline values for cyanobacteria and their toxins in recreational waters are:

Total cyanobacteria: 100 000 cells/mL

Total microcystins: 20 µg/L (expressed as microcystin-LR)

Exceedance of these values, or the development of a bloom indicates the potential for exposure

to cyanobacterial cells and/or their toxins in amounts which may, in some cases, be sufficient to

be harmful to human health. In general, contact with waters where a bloom exists or has very

recently collapsed should be avoided.

An appropriate monitoring program is advantageous to reduce the potential risk of user

exposure to cyanobacterial blooms and their toxins. It is advised that managed recreational

water areas that are suspected or are known to be susceptible to blooms be routinely monitored

during the bathing season. Authorities should visually monitor such supplies for cyanobacterial

growth. A swimming advisory may be issued at the discretion of the responsible authority.

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In the event of bloom development, in order to fully characterize the extent of the risk posed by

the cyanobacterial population, it is further advised that authorities conduct sampling during, and

after the collapse of, the bloom. Should either of the guideline values be exceeded, a swimming

advisory may be issued by the responsible authority. When measuring the toxins it is important

that one measures total microcystins. "Total microcystins" includes both the microcystin that is

occurring free in the water and the microcystin that is bound to or inside the cyanobacterial

cells.

Contact with waters where an advisory has been issued should be avoided until the advisory has

been rescinded. Published texts are available that can provide further information with respect

to the design and implementation of recreational water monitoring programs (e.g., Chorus and

Bartram, 1999)

3. WATER QUALITY IMPROVEMENT STRATEGIES

3.1. Mechanical Removal

3.1.1. Dredging

3.1.1.1. Burnaby Lake is a similar size to Quamichan Lake (Burnaby 770 acres,

Quamichan 773 acres). In 2011 they completed a dredging program to

deal with water quality and provide a suitable site for recreational use.

They removed about 180,000 cubic meters of sediment at a cost of $20.5

million.(From Burnaby Lake Rejuvenation Project Committee Report)

3.1.1.1.1. Capital Cost - $20 million

3.1.1.1.2. Duration of solution – 10 years + depending on runoff

management

3.1.1.1.3. Annual operating cost – none

3.1.1.1.4. Impact on marine life – extensive unless expensive mitigation is

used

3.1.1.1.5. Impact on water users or farmers – farmers may be impacted

depending on dredging design

3.1.1.1.6. Impact on recreational users - No recreation for about 1 year

3.1.1.1.7. Visual impact – significant during dredging, none once completed

3.1.1.1.8. Localized dredging - massive dredging would appear to be

financially impractical or impossible on Quamichan Lake. Localized

dredging to produce some deeper holes in the lake bed would

benefit the survival of trout and other carnivorous fish (See 3.3

below). One such site could be the deeper area near Trumpeter

Point which could be accessible to pumped-in cold water. Another

possible site could be the area two-thirds of the distance between

Art Mann Park and Rainbow Island where melting ice suggests the

presence of ground water springs.

Dredging should be by suction pumping of bottom organic

material. The dredgeate could be composted and/or spread on

agricultural land as a soil amendment.

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3.1.2. Harvesting Vegetation

3.1.2.1. Water lilies - water lilies grow profusely in numerous locations around

Quamichan Lake. During the growing season, from early April to about

August, water lilies sequester significant amounts of nitrogen and

phosphorous from the lake water and leaf growth provides shade and

cooling which can reduce algal growth. Cut water lilies float, so that cut

water lilies could be easily seined and towed to the ramp at Art Mann Park

for harvest and subsequent composting. Mixed fresh water lily leaves and

stems have a dry matter content of approximately 1l.5Yo containing about

0.5% of phosphorous. The harvest of 100 tonnes of wet water lily leaves

and stems removes about 58 Kg of phosphorous from the lake. The

annual water lily growth begins to die back in late August, releasing a high

concentration of contained nutrients back into the lake. This end-of-

summer increase in ammonia nitrogen and phosphorous could contribute

to the growth and toxicity of the observed late summer/fall cyanobacterial

blooms.

3.1.2.2. Duckweed - duckweed is a small floating native, non-toxic water plant that

grows profusely on still or slow moving nutrient-rich water that is

sheltered from wind and wave-action. It forms floating mats, which can be

readily harvested. (See, for example, the duckweed growth in Richard's

Creek under the Herd Road bridge each summer). Duckweed does not

grow on the open water of Quamichan Lake, but occurs in small quantities

in the lower reaches of Maclntyre Creek and along the riparian margins of

the lake. Duckweed biomass is a low fiber, high quality livestock feed for

both domestic livestock and aquatic species such as crayfish. Duckweed

could be grown on Quamichan Lake, in floating compounds which

provided shelter from wind and baffled wave action. Duckweed could also

provide effective harvestable nutrient trapping on sheltered ponds created

on Quamichan tributary streams upstream of their entry points to the lake.

Harvested duckweed contains 7% dry matter removes 0.14 Kg. of

phosphorous per wet tonne or 2 Kg of phosphorous per tonne of dry

matter.

3.1.2.3. Reed Canary Grass - although reed canary grass is considered to be an

invasive species, more efficient harvesting of hay from the flood plane

along Maclntyre Creek would effect a significant removal of nutrients

entering Quamichan Lake. Good quality reed canary grass hay can be

expected to contain 2.5 Kg of phosphorous per tonne.

3.1.2.4. Cyanobacterial Blooms - the very heavy microcystis bloom which began to

develop in late August of 2016 did not clear until early December. By

September 27, the bloom had formed a floating mat about 1/2 cm thick

which covered the whole lake. Rough estimate of the bloom mass and

composition suggested that harvesting of this floating bloom could

remove upwards of 1000 kg of phosphorous from the lake. The floating

cyanobacterial material could be readily separated by passage through a

standard coffee filter.

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The Creative Salmon Ltd. Sea Spring Hatchery on Mt. Sicker Road is

presently installing a large rotary screen on their effluent system, which

can separate algae-sized particles from an effluent system that flows at up

to 2500 US gal/minute. This unit should be operational in about a month.

This type of standard hatchery equipment could be mounted on a float

and used to harvest algal blooms on Quamichan Lake. The rotating screen

is powered by a small electric motor. Sludge is removed from the screen

by using a spray bar supplied by a small high-pressure pump. The sludge

would be delivered into a floating bag which could be emptied

periodically by a septic pump truck for delivery to a composting site. If this

system proved financially feasible it has the potential for making a major

correction to the Quamichan Lake nutrient balance in a short period of

time.

Besides the rotary drum filters described above, there is a possibility that

some of the fixed screen technology now being installed in hatchery

effluent systems could give algal recovery as efficiently as a drum filter.

This alternate technology, powered primarily by the forward motion of the

boat, would involve fewer moving parts and a lower initial cost than the

drum filter.

3.1.3. Skimming

3.1.3.1. Natural skimming - natural skimming of surface water and floating algal

material occurs when the outflow stream, Quamichan Creek, is running.

In2016, the flow in the creek did not resume until late November.

Throughout the year, wind action concentrates algal blooms along the

lakeshore, and on-shore wave action accelerates breakdown of algal

biomass and strips CO2. Organic nitrogen is also removed by the

processes of nitrification and denitrification. Wave and wind action does

not directly remove phosphorous.

3.1.3.2. Mechanical skimming - the equipment described in 3.1.2.4 would appear

to have significant potential for reduction of the nutrient load (especially

phosphorous) in Quamichan Lake and other lakes in the area. The same

equipment would also be effective for harvesting floating duckweed.

3.2. Aeration

3.2.1. Speece Cone Oxygeneration - Speece cones are used in down flow oxygen

bubble contactors. In this equipment inflow water and oxygen enter the inverted,

conical closed tank at the top (small end). As the water and oxygen move

downwards, the tank widens and the velocity of the water decreases so that the

downward velocity balances the buoyancy of the oxygen bubbles. The oxygen

bubbles are suspended until they dissolve completely. The working efficiency for

oxygen absorption is 95-100%. The effluent streams from Speece cone

oxygenation are supersaturated with oxygen and usually require further

treatment to remove excessive nitrogen and carbon dioxide.

3.2.2. Surface Aerators - there are many types of surface aerators which are used for

aeration of ornamental ponds and golf course lakes. Variations of this equipment

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are also used in commercial aquaculture in extensive fish rearing ponds and

effluent systems as well as in sewage treatment facilities. This equipment usually

involves float-mounted electric pumps or rotating paddles which beat air into the

surface water.

Pump-driven fountains are another variant of surface aeration which can have a

significant local effect on cooling and aerating the surfaces of ponds and lakes.

3.2.3. Bubble Column Aeration - there are many types and variations of bottom-

mounted aeration where compressed air is released from the bottom of or at

depth in the water column. Single point bubble column aerators tend to have

large compressors and the high volume stream of large bubbles acts as an airlift

pump that circulates a lot of water. The problem in lakes or ponds that are deep

enough to retain temperature stratification through hot summer weather is that

the airlift pumping action can homogenize the temperature structure so that the

whole lake is warmed to lethal temperature.

3.2.4. Hypolimnetic Aeration - hypolimnetic aeration allows aeration of an anoxic or

poorly oxygenated but cool hypolimnion without mixing the temperature

stratification of the lake. Air is introduced into the bottom of a vertical pipe which

forms an airlift pump that brings cool Hypolimnetic water, that is aerated by the

trapped bubble stream, to the surface. This aerated water is not mixed with warm

surface water, but is delivered via a separate pipe back to the hypolimnion.

3.2.5. Fine Bubble Aerator - This type of aeration is effective in shallow water (down to

3-5 meters) where there is no temperature stratification. In the locally available

fine-bubble equipment (Aquatech Environmental Inc.), air is delivered to the lake

bottom by weighted rubber or PVC tubing. The double, co-extruded tubing

consists of a 1/2" air tube perforated on the top side with fine holes made by

needles having the same diameter as #20 syringe needles. The attached lower

3/4" tube is filled with sand for weight. The air-delivery holes are therefore always

pointing upwards.

Fine-bubble aeration provides efficient local aeration of the whole water column,

strips carbon dioxide and surplus nitrogen gas and ammonia, and promotes

aerobic metabolism and degradation of bottom organic deposits. (The aeration

tubes tend to eat their way down into organic deposits). As the fine-bubble

stream rises, expansion of the bubbles results in significant cooling of the water

column. As the bubble streams break at the surface, the surface tension film is

disrupted, causing floating algae blooms to disperse.

In the pilot fine-bubble aeration system that is operational along the Woodmere

foreshore, eight 200-foot long submerged aeration lines are supplied by 400 feet

of 1 1/4" black poly and rigid PVC pipe connected to a 5HP compressor powered

from the municipal sewage pumping facility between Woodmere and the Garth.

During the 3 operating periods (Aug. 6 - Nov. 1, 2014; Apr. 8 - Oct. 1,2015; Jul. 1 -

Oct. 1, 2016), the system at Woodmere had a very visible effect on dispersing and

metabolizing algae blooms, although it could not keep up to the blanket late

summer bloom of 2016. In each of these 3 there were of extreme anoxia that in

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the lake between August 30 and September 4. At those times very large

populations of sticklebacks and cyprinid minnows were observed to concentrate

in the bubble streams.

3.3. Biological Treatment

3.3.1. Coagulants

3.3.2. Digester Bacteria

3.3.2.1. Concentrated Bacteriological Cultures - The addition of enhanced cultures

of heterotrophic non-pathogenic soil and aquatic bacteria result in

accelerated breakdown of soluble and benthic organic matter.

Commercially available cultures are usually mixtures of different microbial

strains and species to provide an optimum range of substrate capabilities.

Some of these mixtures specialize in the removal of excess organic

nitrogen by conversion of ammonia to first nitrite and then nitrate

(nitrification) and by reducing nitrate to nitrogen gas (denitrification).

Wind/wave action or supplemental aeration strip CO2 and nitrogen

produced by microbial metabolism of benthic organic deposits. Microbial

proliferation and growth also importantly transfers carbon, nitrogen and

phosphorous from bottom deposits to microbial cells suspended in the

water column so that these nutrients are not available for algal growth,

but are more able to be washed out via the lake outlet stream.

Added microbial cultures proliferate as long as substrate is available for

their growth. These high microbial numbers die off or dilute out as initially

excessive substrates decrease in availability. Bacterial augmentation

stimulates the production of zooplankton which feed on bacteria.

Zooplankton such as daphnia in tum are consumed by small fish such as

sticklebacks, cyprinid minnows, juvenile trout or sunfish. The small fish, as

well as snails and insect larvae which also feed on bacterial films, are feed

for larger trout, sculpins and cat fish. A living fish biomass will have a dry

matter content of about 25% which contains approximately 2.5% of

phosphorous. Therefore, a tonne of wet fish biomass contains about 6.25

Kg of phosphorous.

In 2015, 4762 trout of various sizes were stocked in Quamichan Lake by

the Vancouver Island Trout Hatchery in Duncan. This number of 1 Kg trout

would be equivalent to about 30 Kg of phosphorous. If the biomass of

feed-fish was 10x that of trout the total living fish biomass could contain

about 300 Kg of phosphorous that would not be available for algae

growth. The amount of phosphorous sequestered in living fish biomass is

significant relative to the estimated washout of phosphorous (2750 Kg)

but is less than the estimated phosphorous contained in the fall 2016

cyanobacterial bloom (approximately 1000 Kg).

3.3.2.2 Timing of Bacteriological Treatments - as indicated in section 1.1.2 the

annual exchange rate of Quamichan Lake is 0.83 changes per year. Most

of this exchange occurs during the heavy fall and early spring rains. For

maximum effect, augmented bacterial cultures should be applied in

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November and late February to early March to take advantage of high

lake washout rates, high rates of wind aeration and water temperatures

greater than 5 degrees C.

3.3.2.4 Sources of Augmented Bacterial Cultures

3.3.2.4.1 Bacterial Cultures - some of the commercial BactaPur cultures are

available from Dynamic Aqua-Supply Ltd. in Surrey, B.C. A wide

range of BactaPur products are listed in the Pentair Ecosystems Inc.

(Florida) catalogue. The cost of these mixed cultures is reduced by

pre-culturing them with a suitable soluble substrate mix before

applying them to the lake.

3.3.2.4.2 Barley Straw - baled Barley straw is available locally at about $450

per tonne.

3.3.3 Barley Straw - barley straw has been found to be effective in controlling

algal growth in some lakes and agricultural livestock watering and

irrigation ponds. Due to the expansion of local brewing enterprises on

Vancouver Island, there is an increasing local production of barley on

Cowichan area farms. Barley straw is a high-fiber material containing an

energy source for bacterial growth, but very little protein and only 0.09%

phosphorous in dry matter. When added to the ponds, barley straw

develops a culture of cellulolytic bacteria which must extract dissolved

organic nitrogen and phosphorous from the water column for growth,

reducing the dissolved nutrients available for algal growth. Additionally, it

appears that lignin, released as the straw decomposes, can absorb

sunlight with the resultant production of some H2O2 (hydrogen peroxide)

which attenuates the growth of algae. (This last mechanism raises the

question as to whether a low concentration of coniferous lignin (pulp mill

black liquor) might act in the same way).

For application to a lake such as Quamichan, where floating straw bales

would not be compatible with waterskiing, fishing, rowing or aircraft use,

etc., barley straw would be finely hammer-milled prior to use. Powdered

straw blown onto the lake surface would become a submerged, neutrally

buoyant, fine suspension within 24 hours. For maximum effect, this

treatment would be applied several weeks prior to the spring and summer

bloom season. There is a possibility that finely milled barley straw blown

on top of a developing bloom could inhibit further growth of the bloom

by initially shading and then by developing cultures of heterotrophic

bacteria which would strip the surface water of nutrients, depriving the

algae bloom.

3.4. Iron Treatment – Iron binds with the phosphorus and precipitates the phosphorus to the

bottom. This method was used in an experiment in Nakamun Lake in Alberta conducted

by the University of Alberta. The impact on the life in the lake is not well know and

could be detrimental.

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3.5. Alum treatment – Alum binds with the phosphorus and precipitates it to the bottom. It

is often used in sewage treatment facilities where there is no concern about the impact

on marine life.

3.6. Phoslock – this is a patented additive which acts in a similar way to Alum and Iron but is

considered less harmful to life in the lake. It has been used in several lakes. Treatments

for a lake like Quamichan cost about $2 million.

3.7. Ultrasound - Ultrasound has been used medically and industrially for more than half a

century in many diverse ways, including physiological pain relief, cleaning teeth and

jewelry, and navigation. In biomedical and biochemical research, ultrasound has been a

standard procedure for breaking up bacteria, animal and plant cellular tissue and

cellular organelles, for more detailed study. Ultrasound has also been used to prevent

growth of marine algae and deposition of barnacle and mussel spat on marine boat

hulls.

The LG Sonic BV ultrasonic equipment system certainly looks like it has a lot of

potential for preventing or attenuating the growth of cyanobacterial blooms in

Quamichan Lake, and merits further consideration. While ultrasonic equipment has

been demonstrated to work well to kill or reduce algae on still ponds and reservoirs,

application to Quamichan Lake might be impaired due to frequent wind and wave

action on this lake.

Properly calibrated ultrasound technology offers an immediate cosmetic solution to the

eutrophication problem in the lake. However, it does not change the necessity for

reducing the nutrient input to the lake, increasing the washout of nutrients via

Quamichan Creek, optimizing the food chain, and harvesting the nutrient reservoir in

the bottom sediments of the lake.

It is probable that successful operation of ultrasonic equipment would result in

increased growth of rooted water plants such as water lilies which could be harvested.

Also algal control could result in a slower rate of summer heating of the lake surface,

possibly reducing the occurrence of lethal temperature peaks for fish.

3.8. Addition of Cold Water - Temperatures above 22 degrees C are stressful for rainbow

trout and the upper lethal temperature is in the range of 24-25 degrees C The exact

lethal temperature is slightly variable, depending on the level of dissolved oxygen, the

duration of exposure and the degree of previous temperature acclimation experienced

by the fish. As water temperatures rise the metabolic rate (and therefore the oxygen

requirement) of fish increases. At the same time, the solubility of oxygen in the water

decreases with increased temperature. A number of the other fish species in Quamichan

Lake have somewhat higher lethal temperatures than trout.

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The temperature data circulated by David Preikshot for Somenos Lake for 2014, 2015

and 2016 showed peak surface temperatures of greater than 25 degrees C for early July.

Similar temperatures were observed on Quamichan Lake. On July 2, 2015 the surface

temperature at the Woodmere dock peaked at 29.2 degrees C. On July 5, two large

trout, dead for 2 to 4 days, floated up. The following day, ospreys were seen carrying

large fish. Temperatures on Quamichan Lake in the summer of 2016 were slightly lower

so that there might have been a slightly higher survival of stocked trout than in the

previous two summers.

Under more normal conditions, which had existed for several years prior to June of

2014, a fish biomass which included thousands of 2 to 3 year-old trout served as a

significant trap for nutrients, making them no longer available for the growth of algae.

These fish also supported a vibrant sport fishery on the lake.

Maintenance of a normal food chain in Quamichan Lake, which includes top predators

such as trout requires leveling of extreme summer water temperature peaks. One

ameliorating mechanism could be the addition of cold water to the lake during the June

to October hot weather period.

As outlined in section 1.1 above, the agricultural landowners in the Mclntyre Creek basin

have identified a May-June lake level of 30 inches below the top of the concrete wall at

Art Mann Park as being compatible for their crop production. The lowest summer lake

level is about 16 inches (0.4 meters) below this level. If 0.4 meters (approximately 1800

US gal/min.) of 10 degree C cold water were pumped into the lake over the period June

1 - Sept. 30, the result could be an approximate 1 degree C lowering of lake

temperature.

Since pumped-in cold water would not be uniformly distributed over the whole lake

surface, the beneficial effects would radiate out from the point of entry. Therefore, a

much lower inflow of cold water (say 400 US gal/min) could still provide meaningful

local cooling for trout if the water was pumped into a deep area such as the one just

outside of Trumpeter Point.

Cooling water does not need to be fresh water. Cold sea water (10 degrees C or less)

taken from below 50 feet under the surface of Maple Bay would probably be the closest

supply.

3.9. Zeolite

3.8.1 Zeolite Properties - Clinoptilolíte Zeolite is a light, white, soft, micro porous

mineral which, in 8.C., is present in very large deposits (millions of tons) between

Ashcroft and Princeton. It results from felsic volcanic ash where explosive

volcanism produces molten ash which falls back into lakes or the sea. This in turn

results in an expanded interior structure that gives even fine particles of zeolite a

very high intimal surface area. Chemically, clinoptilolite zeolite is a complex

hydrated sodium/potassium alumino-silicate.

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The physical and chemical properties of zeolite include the ability to absorb and

then slowly release about 50% of its weight as water. It will also absorb about the

same volume of organic liquids including crude oil. The interior structure also acts

as a molecular sieve for absorbing heavy metals and trace organic contaminants

such as herbicides and mycotoxins from water, air and soil.

Zeolite is also a natural cation exchange medium with particular specificity for

ammonium ions (or NH4+). In the past 70 years, zeolite has been extensively used

in agriculture in slow release nitrogen fertilizers and for odor control and removal

of ammonia from water supplies and sewage.

In soil and water, zeolite particles become surface substrates for bacterial growth,

including nitriSing/denitrifying bacteria, which access ammonium ions as they are

released from the interior ion exchange. Phosphorous is not directly taken up by

zeolite, but will certainly be taken up by bacterial biomass concentrated by the

zeolite. As well, phosphate anions probably coordinate with ammonium cations

absorbed by the zeolite.

3.8.2. Zeolite Applied to Quamichan Lake - in Quamichan Lake, the application of

ground zeolite in shallow, near shore margins of the lake where wind and wave

action concentrates cyanobacterial blooms, will accelerate the breakdown of the

bloom. The direct absorption of NH4+ -nitrogen will attenuate the further growth

of the bloom and as well, changing the ratio of nitrate to ammonia -N can reduce

the toxicity of the bloom. Also, as zeolite has been shown to absorb trace

organics, it is probable that the algal toxins would also be directly absorbed.

These would subsequently be broken down by bacterial action.

There will be enhanced bacterial growth on zeolite surfaces. Soluble phosphate,

released by decaying algal mass, will be transferred to bacterial biomass. ln turn,

this biomass can be transferred to the food chain or, by increased microbial

loading of the water column, can increase the washout rate of nutrients whenever

Quamichan Creek is flowing.

3.8.3 Zeolite Use on Agricultural Land - There is a large literature on the agricultural

use of zeolite extending back to the late 1940s. Basically, the uptake of ammonia

nitrogen by cation exchange, followed by slow release, conserves organic

nitrogen in agricultural systems. The resulting enhanced bacterial action in soil

also leads to increased retention of phosphorous for crops.

Ground zeolite added to liquid manure pits will absorb ammonium-nitrogen, and

will prevent or reduce loss of ammonia to the air at the time of spreading. Odor

from ammonia during spreading is also eliminated or greatly reduced. Zeolite

spread on agricultural land sloping towards the lake, as well as the semi-

agricultural properties below Maple Bay Road, will trap nutrients that would

otherwise leach into the lake. These trapped nutrients are then available for

increased forage production. Zeolite applied to seasonally flooded land, such as

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the upper Mclntyre basin, will trap post-harvest nutrient residues and prevent

these from leaching into Mclntyre Creek and thence into the lake. Zeolite applied

to the land at the beginning of the crop cycle should still remain effective for

trapping nutrients during the following period when the land is flooded.

Addition of zeolite to poultry litter or, better still, adding zeolite to poultry feed

reduces odor, retains nutrients in poultry manure, and enhances the rate of

manure composting. During the composting process, microbial action will release

phytic acid bound phosphorous which is normally unavailable to digestion by

poultry. Mobility of this released phosphorous is reduced by reaction with

residual calcium and magnesium in the manure to form slowly soluble calcium

phosphate and magnesium ammonium phosphate.

A major benefit of using zeolite agriculturally and directly in the lake is that

zeolite itself does not decompose. Therefore, annual application of zeolite has a

cumulative beneficial effect.

4. ACTIONS CHOSEN FOR FURTHER INVESTIGATION

4.1. At the meeting of the Task Force, Thursday, March 16,2017 the following actions were

chosen for further examination:

4.1.1. Skimming Algae Bloom

4.1.2. Digester Bacteria- concentrated bacteriological cultures

4.1.3. Barley Straw

4.1.4. Zeolite application

4.1.5. Addition of cold water

4.1.6. Improving the flow from the lake at the outlet

4.2. Taking each in turn we have learned the following:

4.2.1. Skimming Algae Bloom - Several fish hatcheries are working of screens to

separate the water from the algae. A modification of those designs would be

needed for the lake.

The first step would be building a small prototype and testing the effectiveness of

different approaches to harvesting the algae. These would not entail great cost but

would at least allow assessment of costs and approach.

4.2.2. Digester Bacteria- The use of augmented bacterial cultures for the breakdown of

ventic organic material and enhancement of phosphorus removal from the lake

involves the enhanced culturing of the existing commensal bacteria from the lake.

This would require setting up several 100 – 1000 l culture tanks near the current

aeration installation at the Woodmere pumping station (to take advantage of the

air supply for aerobic culture). The cultures would be set up in raw lake water with

added ventic sludge. Powdered barley straw with a low level of nitrogen

supplementation would provide a good culture medium. The cultures would be

allowed to multiply for about 1 week before they were added back to the lake.

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Preliminary ticalling would be in the aerated section along the Woodmere

foreshore. Once the fall winds and rains have begun and the lake temperature has

begun to drop, the cultures can be applied more widely in the lake. There cultures

will accelerate the breakdown of the ventic organic deposits, and the continued

(but slower) multiplication of the cultured bacteria will take up additional

phosphorus and nitrogen from the water column. This approach could increase

the flushing of phosphorus by as much as 25%. There microbial bound nutrients

are not available for cyanobacterial growth.

Next steps would entail costing out the tanks, pump etc. and planning for the installation.

4.2.3. Barley Straw - A study was completed by Carole A. Lembi, Professor of Botany at

the Purdue University. Based on her work we have learned:

Barley Straw appears to act as an algaecide as it breaks down, not necessarily

as a collector of phosphorus (not proven either way yet).

The straw should be applied loosely before the algae begins to grow (meaning

now) so water can flow through it, in nets or bags is common.

There are mixed results on its effectiveness on blue green algae.

The treatment rate is 250+/- pounds per surface acre, or about 130 large 1500

lb round bales for our lake at 250 pounds per acre for the 773 acres of surface

area.

In her article, she also makes the point that there could be some issue in

getting requited approvals.

I think this would be a non-starter if it involved large floating lumps (vates or

bags) which I think would be a hazard for boats and aircraft. Spreading finely

chopped straw gives better contact with the water column. Breakdown and

solublization of the barley lignin is primarily by bacterial action on the barley

cellulose which in the process will absolve nitrogen and phosphorus from the

water column, making these nutrients unavailable for algal growth. The

mechanism of action of barley straw is two-fold, i.e. growth of cellulolytic bacteria

which competetiously take up nutrients that would otherwise be available for

algal growth and as well, soluble lignin released from degraded barley straw

apparently attenuates algal growth as a result of hydrogen peroxide produced by

sunlight acting on the lignin.

4.2.4 Zeolite application - There has recently been research on the modification of

zeolites by pre-ion exchange of aluminum, ferric iron, manganese, magnesium

and lanthanum. The resulting modified zeolites can directly absorb phosphate

phosphorus from both lake water columns and benthic sediments without

causing harm to either fish populations or aquatic plants. Work presently

conducted by Dr. Hussein Kazamian at the University of Northern B.C. in Prince

George is particularly interesting because substitution with magnesium produces

modified zeolite which can absorb both phosphorus and ammonium nitrogen in

the form of magnesium ammonium phosphate. MgNH4PO4 has potential use in

agriculture, and magnesium is much less expensive than lanthanum. Phoslock is

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a presently available product for water treatment which consists of 5% lanthanum

exchanged onto bentonite clay. This product is costly, but very effective in

removing phosphorus from lake waters in the form of extremely insoluble LaPO4.

It might prove less expensive to pre-treat clinoptilolite zeolite (which is a better

ion exchanger) with separately purchased lanthanum chloride (purchased from

China) than to buy the bentonite product.

The next steps would be monitoring the work being done and inviting a presentation on the

subject by those developing the product at the appropriate time.

4.2.5 Addition of Cold Water - Local well drillers do not believe that a viable well can

be developed in the proximity of the lake that would provide sufficient water for

this solution.

4.2.6 Improving the flow from the lake - Shaun Chadburn, Engineering Technologist

(Environmental Programs), Municipality of North Cowichan, Tim Kulchyski and

Tom Rutherford visited the outlet of the lake March 23rd 2017 and made the

following observations:

We were able to pull the boat down the creek through shrubs approximately

100m then proceeded by foot another ~50m. At approximately 100m there was

3 trees (almost looked like old power poles) which stretched across the channel –

it appeared to be setup as a footbridge at one point in time (see photo

3747). This makeshift bridge was slightly suspended in the water but did not

appear to affect water movement in any significant way as very little debris was

on the upstream side of it. After this footbridge the downstream grade increased

and a more defined channel with increased velocity was observed.

In summary, the outlet lacked any grade, visible velocity or defined

channel for 100m, then after that point the downstream grade increased,

the channel was more defined and a fairly decent velocity was

observed. We observed only one deciduous stump (<2-inch diameter) that

had been cut by beaver and it was very old - it doesn’t appear that there

are any beavers in this area currently.

There did not appear to be anything that would hold back water from

leaving the lake.”

There should be periodic checking of the outlet area to see that there are no

impediments to movement of the surface film (i.e. with floating algae) at the

entrance to Quamichan Creek. The reports on the absence of impediments to

movement of the outlet water columns is good news. (These surface tension

impediments could be little floating sticks; water lily leaves etc.). The idea is that if

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the right wind is blowing a surface film of floating cyanobacteria would be

pushed by wind and even slight current down the exit creek to the point where

increased stream gradient will carry it further by bulk water column flow.

5. RUNOFF REDUCTION ACTIONS

5.1. Introduction - To move ahead on runoff reduction strategies, it is important to get a

grasp of where the most phosphorus is coming from. The phosphorus loading report

prepared in 2008 is the best source of information on where it is coming from because

of the wealth of information it contains. David Groves has spent a lot of time studying

the report and making analysis of the lake water.

He has found that the current concentration of phosphorus in the lake is much higher,

averaging .19 mg/L and ranging up to .22 mg/L in 2015 compared averaging .06 mg/L in the

period up to 2007.

Using the theoretical water balance developed in the phosphorus loading study quoted

earlier in this report which estimated the outflow of the lake at 11,207,588,000 m3 we can

estimate that the current outflow of phosphorus at:

11,207,558 m3 = 11,207,558,000 Liters

11,207,558,000 x an average of .19 mg/L

= 2616 KG of phosphorus leaving the lake compared to 132.6 KG in the 2007 report

Assuming the phosphorus inflow from farms remains similar to the 2007 report at 133.4 KG

because there have been no changes to the agricultural activity, that would mean 2482 KG is

coming from other resources.

The phosphorus from other sources may have been under estimated in 2007 because of

problems in reading the phosphorus content in the streams on the east side of the lake. In

the standard phosphate water analysis, the samples are read within about 10-15 minutes of

the addition of reagents. The surface flows sampled at 1840 Stamps Rd., Martin Place and

Stanhope Creek (the agricultural / rural acreages) have probably yielded accurate analytical

results. The creeks on the east side of Quamichan Lake contain enough iron to complex

soluble phosphate to the extent that colour development in the standard phosphate water

analysis is very slow. The colour takes in the order of 1-5 hours for full colour to develop.

Readout at 10-15 minutes gives a zero or very low phosphate result. Samples from the

agricultural area, as from the lake water give rapid colour development that does not

significantly increase over a 1-5-hour period.

These numbers are misleadingly precise. They are estimates. At the same time it is

reasonable to conclude:

1. The phosphorus load in the lake water has increased because of increased release from

the bottom and none-farm sources.

2. We should take steps to reduce the phosphorus coming from farms but the emphasis

should be on the none-farm sources.

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5.2 All the literature points out that the input of nutrient comes from the following sources:

5.2.1 POINT SOURCES

5.2.1.1 Wastewater effluent, both municipal and industrial

5.2.1.2 Runoff and leachate from waste disposal sites

5.2.1.3 Runoff and infiltration from animal feed lots

5.2.1.4 Runoff from mines, oil fields, and unsewered industrial sites

5.2.1.5 Storm sewer outfalls

5.2.1.6 Runoff from construction sites larger than two hectares

5.2.1.7 Overflows of combined storm and sanitary sewers

5.2.2 NON-POINT SOURCES

5.2.2.1 Runoff from agriculture (including return flow from irrigated agriculture)

5.2.2.2 Runoff from pasture and range

5.2.2.3 Urban runoff from unsewered areas

5.2.2.4 Septic leachate and runoff from failed septic systems

5.2.2.5 Runoff from construction sites smaller than two hectares

5.2.2.6 Runoff from abandoned mines

5.2.2.7 Atmospheric deposition over a water surface

5.2.2.8 Activities on land that generate contaminants, such as logging, wetland

conversion, construction and development of land or waterways

Erosion and Construction Sites

A University of Wisconsin paper titled “Polluted Urban Runoff” identifies construction areas as

the biggest source of nutrient load.

“The Wisconsin Department of Natural Resources (DNR) estimates that an average acre under

construction delivers 60,000 pounds (30 tons) of sediment per year to downstream waterways,

which is much more than any other land use. Two factors account for the large amount of

sediment coming from construction sites — high erosion rates and high delivery rates.

Construction sites have high erosion rates because they are usually stripped of vegetation and

topsoil for a year or more.

Typical erosion rates for construction sites are 35 tons to 45 tons per acre per year as compared

to 1 to 10 tons per acre per year for cropland. Even more importantly, construction sites have

very high delivery rates compared to cropland. During the first phase of construction, the land is

graded and ditches or storm sewers are installed to provide good drainage. This also provides

an efficient delivery system for pollutants. Typically, 50% to 100% of the soil eroded from a

construction site is delivered to a lake or stream, compared to only 3% to 10% of the soil from

cropland delivered to lakes or streams.”

Another way of looking at it is illustrated by a set of calculations done by Christopher Justice a

resident on the east side of the lake. He just looked at residences and made the following

rough calculations concerning the phosphorus from households:

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Source

Estimate of

phosphorus

brought in

annually

Estimate of

phosphorus

removed

annually

Estimate of

phosphorus

remaining in

watershed

annually

Guess of

accuracy of

estimate of

phosphorus

remaining in

watershed

Food (houses on

sewer)

1865 kg 1865 kg 0 + or – 5%

Food (houses on

septic)

1270 kg 0 kg 1270 kg + or – 25%

Pet food 1110 kg 277 kg 832 kg + or – 25%

Soil and

compost

370 kg 0 kg 540 kg + or – 50%

Fertilizer 540 kg 0 kg 540 kg + or – 50%

Detergents ? ? ? ?

Firewood 1850 kg 50% ? 925 kg + or – 75%

Total 7005 kg 3067 kg 3937 kg + or – 50%

Taking all this into consideration suggests we should focus on residential sources and erosion.

5.3 Erosion Reduction Actions

5.3.1 Runoff Creeks

Runoff creeks and ditches are a major source of erosion due to their fast pace of runoff

and lack of foliage or boulders to slow their movement.

This suggests that the Municipality review ditch clearing practices and consider

methods that preserve vegetation and sediment trapping materials.

5.3.2 Construction Sites Management

The following is taken from journal “Ecological Applications” (Volume 8, Number 3, August

1999)

“Construction sites are a critical concern as sources of nonpoint pollution. Although construction

sites may occupy a relatively small percentage of the land area, their erosion rates can be

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extremely high and the total nonpoint pollution yield quite large. Erosion rates from watersheds

under development approach 50,000 metric tons per square kilometer a year, compared to 1,000

to 4,000 metric tons per square kilometer for agricultural lands and less than 100 metric tons for

lands with undisturbed plant cover. Eroded material from construction sites contributes to siltation

of water bodies as well as eutrophication.”

5.4 Human activity

5.4.1 Education on nutrient loading issues including the use of fertilizer

Small lot owners are more likely to over fertilize because they are generally less

knowledgeable. They may use all their purchase of fertilizer even if it is not

needed. Similarly, they are not all aware of the issues surrounding erosion and

runoff from hard surfaces or as careful with washing cars, cleaning boats etc.

There are several education brochures that could be distributed to homeowners

around the lake.

5.4.2 Expansion to sewered areas and improving septic systems

By a count done by Christopher Justice there are 750 septic systems in the

drainage area of the lake. Efforts to connect more households to the sewer must

overcome the resistance to the cost of the connections and the fact that there is

no requirement for homeowners to incur costs to keep their septic system

operating effectively. Under current requirements in North Cowichan the only

time inspection occurs is when a home is sold and there is a property inspection

on behalf of the buyer. The Municipality could:

5.4.2.1 Be more active in expansion of the sewer area.

5.4.2.2 Follow the lead of other municipalities in requiring assessment of septic

systems to ensure they are not polluting surrounding water bodies.

5.5 Farm Fields

5.5.1 Feed Treatment - there are several papers on the impact of adding Zeolite to

animal feeds. Generally, the studies suggest that the treatment reduces odor and

reduces runoff by slowing the release of nutrient from the manure.

(Using Zeolites in Agriculture Frederick A. Mumpton Department of the Earth

Sciences State University College Brockport, NY 14420)

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5.5.2 Nutrient Traps in Field - “Applying zeolite to the soil can improve its ability to

hold nutrients and water Zeolite is a natural super porous mineral (part of a

group of hydrated alumino silicates). It carries a negative charge balanced by freely

moving cations with positive charges. this provides an ideal trap for positive cations

like nitrogen rich ammonium and potassium which are then released when

demanded by plants.

Zeolites have a very open framework with a network of pores giving it a large

surface area for trapping and exchanging valuable nutrients.

More efficient fertilizer use

With the current high price of ammonium fertilizers zeolite can be used to extend

their efficiency and performance. Blending fertilizer with zeolite can produce the

same yield from less fertilizer applied because of the reduction of volatilization and

leaching losses. It is particularly suitable for banding under drip irrigation planting

where it will assist water infiltration, distribution and retention. When fertigation is

practiced it will actively hold the nutrients in the rootzone. (Zeolite Australia PL)’”

It has been suggested that the addition of a zeolite strip at the edge of fields would

trap nutrient and reduce the runoff to streams and lakes.

5.5.3 Plantings to trap nutrient adjacent of farm activity - planting trees at the edge of

fields has benefit to the farm and reduces the runoff. Farmers Weekly published

an article February 2016 titled 9 Reasons to Plant Trees. It listed all the

advantages:

Managing soil erosion

Improve animal welfare

Shelter for crops

Water management

Cut pollution

More energy efficient

Added revenue

The trees sequester nutrient and their root structure reduces runoff.

5.6 Zoning / Regulatory Amendments

5.6.1 Runoff Management built into zoning requirement- In some jurisdictions, there is

a requirement built into the bylaws that the runoff from a site after development

must be equal to or less than before development.

5.6.2 Storm Water Utility Fees - storm water drains require maintenance – keeping

settling ponds functional, ensuring ditches are not eroding soil and are catching

nutrient etc. All those costs relate to the storm water coming from developments.

The Municipality could include the storm water in the Sewer Utility and make

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appropriate charges to provide the funds to manage the water once it leaves the

source property.

5.6.3 Increasing the density of development - the work done by Christopher Justice

shows that unsewered lot development and even sewered houses are a greater

source of nutrient for the lake than more dense developments like row housing

and low-rise developments. The denser developments would be on sewer, have

gas fireplaces, smaller dogs and gardens managed by gardeners, not

homeowners, all resulting in less nutrient runoff impacting the surrounding water

bodies.

6. MONITORING FOR CYANOBACTERIA TOXINS

The Government of Canada has provided guidelines for the monitoring of both

cyanobacteria and their toxins. David Conway, the Municipal Engineer is already exploring a

method to apply such monitoring to Quamichan Lake. Such monitoring would ensure timely

warnings about dangerous levels of Toxins in a similar way to the approach taken in other

jurisdictions on Vancouver Island.

7. MONITORING Run-off Streams

A program of regular monitoring of certain run-off streams should be started so that we

have an ongoing record of how actions taken are impacting the nutrient reaching the lake.

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