hydraulic zone 2 - manitoba hydro€¦ · and modified the lake’s main outlet channels by filling...

Regional Cumulative Effects Assessment

NAD 1983 UTM Zone 14N

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OminiwinBy-PassChannel

Kiskitto-MinagoDrainage Channel

Stan CreekChannel

KisipachewukChannel

Improvement

HydraulicZone 205UD001

05UB008

05UB013

05UB017

05UB007

KiskittoC.S.

CrossLakeWeir

BlackDuckC.S.

PimicikamakCross Lake

(NAC)

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Minago

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L

Lake

Pakwa

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Gormley

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FraserL

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ConlinClarke

Resting

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Setting

RockIsland

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RiverCreek

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Metchanais

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Scatch Nelson

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LOpastakow

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LakeLake Okawi

Creek

Butterfly

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Echimamish

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JenpegG.S.

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ChurchillHudson

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Manitoba Hydro; Government of Manitoba; Government of Canada

Manitoba Hydro - Hydraulic Operations

1.0

01-OCT-15

LegendGenerating Station (Existing)Control Structure (Existing)Station GaugeFlow DirectionDiversion (Existing)Dyke

First Nation ReserveWatercourse Boundary (Predevelopment)Watercourse Boundary (Predevelopment)Mapping Alignment IssueWatercourse (Existing)RCEA Hydraulic Zone04-DEC-15

Hydraulic Zone 2 Cross Lake and Surrounding Area

1 of 2

Notes:- FOR ILLUSTRATIVE PURPOSES ONLY- Northern Affairs Community (NAC)- Watercourse Boundary Predevelopment - Mapping Alignment Issue See RCEA Phase II (PreambleSection 1.3.3) for more details.

Map 4.3.2-2



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CrossLakeWeir

Metchanais

Duck

Lake

Island

BruneauDugas LL

Bear

Nelson

LMuskeko

River

Island

WaweL

Pipestone

Cross I

LAsawapesewanannis

Sipiwesk

Puskwatinow

LOpastakow

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LakeLake Okawi

Butterfly

Hairy

Lake

Echimamish

MuirL

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L

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WhiteRabbit

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LBlackRabbit

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KotenkoL

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River

Mistasinni

R

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Suketukaw

Waweysew

Ochechako

Bjornson L

L

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Lawford

Lake

RobinsonLake

Lawford

Porcupine

Hill

Wakehao

Lake

Mowat

Carrot

L

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L

Breland

L

LPrior

Kapechekamasic

Creek

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LLogan

JenpegG.S.

PimicikamakCross Lake

(NAC)

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ChurchillHudson

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LegendGenerating Station (Existing)Control Structure (Existing)Station GaugeFlow DirectionDiversion (Existing)Dyke

First Nation ReserveWatercourse Boundary (Predevelopment)Watercourse Boundary (Predevelopment)Mapping Alignment IssueWatercourse (Existing)RCEA Hydraulic Zone04-DEC-15

Hydraulic Zone 2 Cross Lake and Surrounding Area

2 of 2


Map 4.3.2-2

REGIONAL CUMULATIVE EFFECTS ASSESSMENT – PHASE II PHYSICAL ENVIRONMENT – WATER REGIME

DECEMBER 2015 4.3-28

Figure 4.3.2-14: Monthly Average Cross Lake Water Levels

CROSS LAKE WEIR PROJECT

The Cross Lake Weir was developed to mitigate the effects of LWR by increasing the average water level and reducing the range of water levels on Cross Lake. Construction of the weir was completed in 1991 and modified the lake’s main outlet channels by filling in a portion of the centre channel and excavating a portion of the east channel. The mean monthly water level after completion of the weir rose to 681.5 ft (207.7 m), 1.8 ft (0.5 m) higher than the pre-LWR average. The increase is partially attributable to the weir but also partially because since 1992 the average total Lake Winnipeg outflow has been 19% higher than the pre-LWR average because of wetter conditions. Also, since installation of the weir, the seasonality of water levels has more closely resembled natural conditions (Figure 4.3.2-14). A seasonal flow reversal is still found to occur in low to average flow years, while in high flow years the seasonal flow pattern remains similar to the natural condition (Figure 4.3.2-15). The Cross Lake weir helps to mitigate the effects of higher flows by allowing greater discharge at high lake levels than was possible under natural conditions. Installation of the weir reduced the magnitude of water level variations, including those experienced during the Ice Stabilization Program. The average monthly water level variation reduced from 1.0 ft (0.3 m) post-LWR prior to installation of the weir to 0.7 ft (0.2 m) with the weir, which is close to the pre-LWR average of 0.6 ft (0.2 m). Figure 4.3.2-16 shows the average, historical range and upper and lower quartiles for daily water levels post-LWR after installation of the weir on Cross Lake from 1992 to 2014. Water levels during the 2003 drought and 2011 flood are also included. The 2011 flood resulted in record high water levels on Cross Lake during much of the open water season as Jenpeg GS was operated to maximize discharge as required by The Water Power Act Licence when Lake Winnipeg is above 715.0 ft (217.9 m). In 2003, water level declined as the drought conditions developed over the

205.4

205.7

206.0

206.3

206.7

207.0

207.3

207.6

207.9

208.2

208.5

674

675

676

677

678

679

680

681

682

683

684

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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Pre-LWR 05UD001 (1918-1976)Post-LWR, Pre-Weir 05UD001 (1976-1991)Post-LWR, Post-Weir 05UD001 (1992-2014)



course of the year and reached post-LWR/post-weir record lows for the second half of the year as outflows from Lake Winnipeg were reduced to conserve water.

Figure 4.3.2-15: Monthly Average Cross Lake Water Levels during High Flow Years

Figure 4.3.2-16: Daily Cross Lake Water Levels

206.0

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Highest flow years Pre-LWR 05UD001 (1966, 1970, 1974, 1975)Highest flow years Post-LWR 05UD001 (2005, 2009, 2010, 2011)

205.4

206.0

206.7

207.3

207.9

208.5

209.1

209.7

674.0

676.0

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682.0

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686.0

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Jan 01 Feb 01 Mar 01 Apr 01 May 01 Jun 01 Jul 01 Aug 01 Sep 01 Oct 01 Nov 01 Dec 01

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Range 1992-2014 Average 1992-2014 Lower quartileUpper quartile 2011 2003



Operation of LWR does not cause large hourly or daily water level variations on Cross Lake. As shown in Table 4.3.2-2, the 95th percentile daily variation on Cross Lake is less than 0.25 ft (0.1 m) pre-LWR and post-LWR both before and after construction of the weir. Table 4.3.2-2 also provides average and 95th percentile weekly and annual water level variations. The average weekly water level variation increased by 0.1 ft (0.03 m) while the average annual variation increased by 2.9 ft (0.9 m) before construction of the weir and 0.6 ft (0.2 m) with the weir as compared to pre-LWR conditions.

Table 4.3.2-2: Daily, Weekly and Annual Cross Lake Water Level Variation at Gauge 05UD001

Variation Pre-LWR 1 Mean (ft)

1918–1976

Post-LWR Pre-Weir Mean (ft)

1976–1991

Post-LWR Post-Weir Mean (ft)

1992–2014

Pre-LWR 95th Percentile (ft)

1918–1976

Post-LWR Pre-Weir 95th Percentile (ft)

1976–1991

Post-LWR Post-Weir 95th Percentile (ft)

1992–2014

Daily 0.0 0.1 0.1 0.2 0.2 0.2

Weekly 0.2 0.3 0.3 0.5 0.9 0.7

Annual 4.0 6.9 4.6 5.4 10.1 6.7

Note: Annual variation is max-min in each year June–May. 1. LWR = Lake Winnipeg Regulation.

The effect of Jenpeg GS cycling on Cross Lake is described in Section 4.3.2.2.3. This section also describes larger water level variations that occur on Cross Lake during transition periods from times when Jenpeg GS is being operated at maximum discharge to times when Jenpeg GS is operated to conserve water in Lake Winnipeg as part of LWR operations. An example was August 2013 when Cross Lake water levels dropped 2.5 ft (0.8 m) from upper quartile to near average over a period of 18 days following flow reductions at Jenpeg GS as Lake Winnipeg dropped below 715 ft (217.9 m). Similar events can also occur because of LWR operations in late winter/spring when outflows at Jenpeg GS are typically reduced from maximum during the winter months to store water in Lake Winnipeg as energy demand is reduced with warmer weather. The Cross Lake Weir has increased the minimum water level and reduced the range of water levels experienced on Cross Lake during these types of operations.

PIPESTONE, WALKER, AND DUCK LAKES

Pipestone Lake is located on the East Channel of the Nelson River just upstream from Cross Lake. Water levels on Pipestone Lake are generally a function of water levels on Cross Lake, while flow in the Nelson River East Channel also has a minor influence on lake levels. As a result, LWR impacts Pipestone Lake in a similar manner to Cross Lake.

Walker Lake is located approximately 25 mi (40 km) east of Cross Lake and is connected to it by the Walker River. Midway along the Walker River between Cross Lake and Walker Lake is a set of rapids that have long been known to be reversing. The flow direction on Walker River depends on the elevation of Cross Lake relative to Walker Lake. When Cross Lake elevation is above 681 ft (207.6 m) it has a direct influence on the level of Walker Lake (Manitoba Hydro 1998). When Cross Lake is below this level, Walker Lake level is only a function of local inflows. As a result, LWR periodically affects Walker Lake because LWR affects the frequency, duration, and timing of high water level events on Cross Lake. Prior



to LWR (1918–1976), water levels on Cross Lake were above 681 ft (207.6 m) about 26% of the time. Post-LWR (1977–2014), water levels on Cross Lake have been above 681 ft (207.6 m) about 44% of the time. As a result, water levels on Walker Lake have been influenced by water levels on Cross Lake more frequently since LWR began. However, it is difficult to separate the effects of LWR from the effects the Cross Lake Weir and wetter conditions in the post-LWR period.

Duck Lake is located downstream from Cross Lake along an area where the Nelson River splits into two channels, just upstream from Sipiwesk Lake. Lake Winnipeg Regulation affects Duck Lake in a similar manner to Cross Lake including a changed seasonal flow pattern and greater water level variation. Similar to the Jenpeg GS forebay and Cross Lake, larger water level variations occur on Duck Lake during transition periods from times when Jenpeg GS is being operated at maximum discharge to times when Jenpeg GS is operated to conserve water in Lake Winnipeg as part of LWR operations. An example was August 2013 when Duck Lake water levels dropped 3.7 ft (1.1 m) over a period of a month following flow reductions at Jenpeg GS as Lake Winnipeg dropped below 715 ft (217.9 m). High water levels in 2011 also resulted in a new channel being formed at the lake outlet, which resulted in lower water levels on Duck Lake going forward.

4.3.2.3.4 Ice Conditions

The Ice Stabilization Program discussed in Section 4.3.2.2.4 can affect ice conditions on Cross Lake. This is because Jenpeg GS operations can increase water level fluctuations and potentially contribute to the formation of slush ice on Cross Lake. Slush ice forms when lake water mixes with a layer of snow sitting on top of a competent ice cover. It makes winter transportation and resource harvesting, including fishing and trapping, more difficult and dangerous for resource users. As Cross Lake is heavily used during the winter for transportation, operating decisions are made in a manner that attempts to reduce the potential to create slush ice. Large increases in water levels on Cross Lake after freeze-up can also increase the amount of slush ice on the lake. As a result, Manitoba Hydro now increases Jenpeg GS outflows to the target winter flow prior to freeze-up to allow Cross Lake to freeze at a higher level. Slush ice can also form naturally if sufficient snow accumulates on and depresses the ice surface enough to allow water to flow over the ice or if ice constrictions at a lake’s outlet cause the water level on a lake to rise and force water upwards through cracks in the ice.

An ice thickness study was undertaken for Cross Lake in 1983 to establish whether Lake Winnipeg Regulation contributed to the severity of slush ice by reducing ice thickness. The study demonstrated that in many areas, including the western main body of the lake, the northern area, downstream from the East Channel entrance and the southern part of the community, the increased West Channel flow with LWR has resulted in increased ice thickness. Throughout the rest of the lake, including the central and northern reaches within the community, none of the natural or Manitoba Hydro influenced factors considered seemed to have a consistent effect on ice thicknesses one way or another (Manitoba Hydro 1983).

Downstream from Cross Lake, higher winter flows created by LWR have the potential to affect ice conditions and may result in areas remaining ice free for longer periods.



4.3.2.4 Hydraulic Zone 3 – Sipiwesk Lake to Kelsey Generating Station

Hydraulic Zone 3 includes Sipiwesk Lake and the Nelson River from the outlet of Sipiwesk Lake to the Kelsey GS (Map 4.3.2-3). Some of the other lakes in this hydraulic zone include Landing, Hunting, Prud’homme, Cauchon, and Goose Hunting lakes, which are all tributaries to the Nelson River. The Kelsey GS was constructed between 1957 and 1961 to supply the International Nickel Company’s mining and smelting operations and to supply electricity to the City of Thompson.

4.3.2.4.1 Manitoba Hydro Operations

Operation of both LWR and the Kelsey GS affect the water regime in this hydraulic zone. Lake Winnipeg Regulation affects the seasonal timing of inflows to Sipiwesk Lake. Kelsey GS affects water levels on the Nelson River and surrounding lakes upstream to and including Sipiwesk Lake. For the first 16 years of operation (1961–1976), Kelsey GS had no effect on flows because it was operated as a run-of-the-river plant, using the flow of the river as it occurred. Starting in 1977, Kelsey GS operations became more integrated in the whole hydroelectric system. Operations were modified to more effectively utilize the reservoir of Kelsey GS’s forebay on an infrequent basis to supplement flows over a period of about a month or so, or to increase the gradient out of Sipiwesk Lake to alleviate winter hydraulic restrictions (Manitoba Hydro-Split Lake Cree Joint Studies 1996).

Flow changes at Kelsey GS immediately affect the water level upstream from the GS and the effect moves progressively upstream to Sipiwesk Lake. Although the forebay at Kelsey GS is generally held constant, when they do occur (see Kelsey GS cycling below) hourly water level variations at the Kelsey GS forebay can influence water levels from the generating station to the outlet of Sipiwesk Lake. Changes to the daily average flow at Kelsey GS can affect Sipiwesk Lake and several other lakes, which are tributaries to the Nelson River.

4.3.2.4.2 Data Manitoba Hydro has a continuous record of daily water levels in the Kelsey GS forebay since August 1957. Flows in this hydraulic zone have been monitored at WSC station 05UE004 (Nelson River below Sipiwesk Lake) from 1951–1958, and by Manitoba Hydro at Kelsey GS since 1960. Water levels have also been monitored at WSC station 05UD006 (Sipiwesk Lake at Forestry Dock) since 1965.



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FallsHalfway

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Opastakow

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WalkerKapaspwaypanik

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HancockL

Allbright

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Waweysew

Ochechako

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Wapisew

Goulet

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ChurchillHudson

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1.0

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LegendStation GaugeFlow Direction

First Nation ReservePark (Provincial)Watercourse Boundary (Predevelopment)Watercourse Boundary (Predevelopment)Mapping Alignment IssueWatercourse (Existing)RCEA Hydraulic Zone

04-DEC-15

Hydraulic Zone 3Sipiwesk Lake to

Kelsey Generating Station1 of 2


Map 4.3.2-3



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PAINT LAKEPROVINCIAL

PARK

HydraulicZone 3

Thompson

BaileyL

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GrassRiver

Mystery

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Lake

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Strong

Odei

McKillopLake

L

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RiddochL

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BuckinghamLake

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Teal L

Brannigan

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L

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Bald

Armstrong

Grass

Eagle

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PikwitoneiLake

LL

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German

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Prud'homme

Nelson

LEaster

Edna

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MinistikL

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Sinclair

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Maltby

Neepionikup

LKwaskwaypichikin

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Archibald

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Dafoe

GunnLake

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AikenRipple

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Evelyn

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Joy

HeadLake

Lake Cuddle

Lake

LakeSilsby

HighHillLake

Diana

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L

L

WestCyril

River

War Lake

L

SurpriseL

Cyril

Apiswetiko

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Wetiko

Diana

KelseyG.S.

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ChurchillHudson

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LegendTownGenerating Station (Existing)Flow DirectionDyke

First Nation ReservePark (Provincial)Watercourse Boundary (Predevelopment)Watercourse Boundary (Predevelopment)Mapping Alignment IssueWatercourse (Existing)RCEA Hydraulic Zone

04-DEC-15

Hydraulic Zone 3Sipiwesk Lake to

Kelsey Generating Station2 of 2


Map 4.3.2-3



4.3.2.4.3 Key Hydraulic Features and Indicators

KELSEY GENERATING STATION

Based on the short record of data available, impoundment of the Kelsey GS forebay increased water levels by approximately 30 ft (9.1 m). Impoundment flooded 63.5 sq mi (164.5 km2) of land, increasing the surface area of the rivers and lakes between Sipiwesk Lake and Kelsey GS from approximately 233 to 297 sq mi (603 to 769 km2). Since construction was completed in 1961, the Kelsey GS forebay is normally controlled to operate just below its upper licensed limit of 605 ft (184.4 m) to optimize power production (Figure 4.3.2-17). For power production reasons, the forebay is drawn down periodically but typically not below 600 ft (182.9 m) (Figure 4.3.2-17). Figure 4.3.2-18 shows the average, historical range and upper and lower quartiles for daily water levels after impoundment of the Kelsey GS forebay from 1961–2014. This figure also shows that water levels typically follow the same pattern regardless of whether flows are very low (2003 drought) or very high (2011 flood). Water levels are typically drawn down during the late-winter to increase power production with the forebay being refilled in early spring when energy demand is lower.

Operation of Kelsey GS does not typically cause large hourly or daily water level variations in the Kelsey GS forebay area. As shown in Table 4.3.2-3, the average daily variation in the Kelsey GS forebay is less than 0.2 ft (0.05 m). Table 4.3.2-3 also provides average and 95th percentile weekly and annual water level variations.

Table 4.3.2-3: Daily, Weekly and Annual Kelsey Generating Station Forebay Water Level Variation

Variation Post-LWR 1

Mean (ft)

1977–2014

Post-LWR 95th Percentile (ft)

1977–2014

Daily 0.1 0.3

Weekly 0.4 1.2

Annual 3.5 7.3

Note: Annual variation is max-min in each year June–May. 1. LWR = Lake Winnipeg Regulation.



Figure 4.3.2-17: Kelsey Generating Station Forebay Daily Water Level Duration Curve

Figure 4.3.2-18: Daily Kelsey Generating Station Forebay Water Levels

181.1

181.7

182.3

182.9

183.5

184.1

184.7

185.3

594

596

598

600

602

604

606

608

0 10 20 30 40 50 60 70 80 90 100

Kel

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Fore

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Wat

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Ele

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Kel

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Fore

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Wat

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Ele

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Percent of time less than

All Data 1961-2014

181.1

181.7

182.3

182.9

183.5

184.1

184.7

185.3

594.0

596.0

598.0

600.0

602.0

604.0

606.0

608.0


Kel

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Fore

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Wat

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The monthly average discharge at Kelsey GS pre- and post-LWR in Figure 4.3.2-19 shows that LWR increased winter flows at Kelsey GS. Although LWR can also increase flows during the open water season under flood conditions, the available record indicates that on average LWR decreased open water flow. Long-term average flow, which is not affected by hydroelectric development, is approximately 89,000 cfs (2,520 cms) in the pre-LWR period (1951–1976) and 78,000 cfs (2,210 cms) in the post-LWR period (1977–2014). Figure 4.3.2-20 shows the average, historical range and upper and lower quartiles for daily Kelsey GS discharge in the pre-LWR (1951–1976) and post-LWR (1976–2014) periods. Figure 4.3.2-21 shows the post-LWR period only with the 2003 drought and 2011 flood data included. The 2003 drought resulted in very low Kelsey GS discharge for most of the year, reaching record lows for the last few months of the year. The 2011 flood resulted in record high discharge at Kelsey GS for most of the year.

Manitoba Hydro completed a more detailed characterization of the water regime in this hydraulic zone in 2005 including an assessment of the potential effects of the Kelsey GS Re-runnering Project which was completed in 2013 (Manitoba Hydro 2005).

Figure 4.3.2-19: Monthly Average Kelsey Generating Station Discharge

0

566

1,133

1,699

2,265

2,832

3,398

3,964

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Pre-LWR (1951-1976) Post-LWR (1977-2014)



LWR = Lake Winnipeg Regulation.

Figure 4.3.2-20: Daily Pre-LWR (1951–1976) and Post-LWR (1976–2014) Kelsey Generating Station Discharge

LWR = Lake Winnipeg Regulation.

Figure 4.3.2-21: Daily Post-LWR (1976–2014) Kelsey Generating Station Discharge

0

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cfs)

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Range 1951-1976 Median 1951-1976 Lower quartile Upper quartile

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

566

1,133

1,699

2,265

2,832

3,398

3,964

4,531

5,097

5,663

Month

Kel

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Dis

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cms)

Range 1976-1978 Median 1976-2014 Lower quartile Upper quartile

0

283

566

850

1,133

1,416

1,699

1,982

2,265

2,549

2,832

3,115

3,398

3,681

3,964

4,248

4,531

4,814

5,097

5,380

5,663

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

110,000

120,000

130,000

140,000

150,000

160,000

170,000

180,000

190,000

200,000

210,000


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Range 1976-2014 Median 1976-2014 Lower quartile

Upper quartile 2011 2003



KELSEY GENERATING STATION CYCLING

In addition to infrequent drawdown of the Kelsey GS forebay as described above, Kelsey GS outflow is cycled at times so that more water flows and more energy is produced during the day when energy demands are higher and less water flows overnight. This operation causes the forebay to drop throughout the day and refill overnight. Downstream, in the tailrace, the opposite happens with the water level rising during the day and falling overnight. Cycling did not occur from 1960–1976 and from 1977–2014, cycling at Kelsey GS occurred about 10 to 15% of the time. The decision to cycle depends on a number of factors including energy demand, price, and amount of other available generation. Cycling occurs more frequently in low flow years and from 1994–2014, which has generally been a wetter period, cycling at Kelsey GS has occurred less than 5% of the time.

Figures 4.3.2-22 to 4.3.2-25 below provide a snapshot of the effects of cycling at Kelsey GS on the forebay and tailrace water levels as well as the Sipiwesk Lake and Split Lake water levels from July 2003. All figures show that during the entire month of July, Kelsey GS discharge during the day was about 55,000 cfs (1,557 cms) and reached 60,000 cfs (1,699 cms) on three days. The figures also show that Kelsey GS discharge was reduced each night to about 40,000 cfs (1,133 cms), with several nights reducing to about 32,000 cfs (906 cms).

Figure 4.3.2-22 shows that the cycling operation typically resulted in about a 0.5 ft (0.15 m) water level variation between the day and night in the Kelsey GS forebay with the largest variations at up to 1.0 ft (0.3 m). Figure 4.3.2-22 also shows that water levels were maintained within a 1.0 ft (0.3 m) range from 604–605 ft (184.1–184.4 m) over the entire month of July.

Figure 4.3.2-23 shows that water levels on Sipiwesk Lake remained fairly stable throughout the month of July in 2003 and were not affected by the cycling operation at Kelsey GS. The water level variations observed in the forebay would have gradually reduced with distance upstream from Kelsey GS along the Nelson River.

Figure 4.3.2-24 shows that the cycling operation at Kelsey GS resulted in the largest water level variations immediately downstream from the station. Here water levels varied typically by about 1.5 ft (0.5 m) with the largest flow changes noted above resulting in as much as a 2.5 ft (0.8 m) variation between water levels during the day and overnight.

Moving downstream from Kelsey GS, water level variations because of the cycling operation decrease and at Split Lake, the water level variation is typically decreased to about 0.1 ft (0.03 m) as shown in Figure 4.3.2-25. This figure also shows that the range of hourly water levels on Split Lake during the month of July in 2003 was less than 0.4 ft (0.1 m).



Figure 4.3.2-22: Total Discharge and Forebay Water Level at Kelsey Generating Station during Cycling Operation in July 2003

Figure 4.3.2-23: Total Discharge at Kelsey Generating Station and Sipiwesk Lake Water Level during Cycling Operation in July 2003

602.0

603.0

604.0

605.0

606.0

607.0

608.0

609.0

610.0

0

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Kelsey Hourly Total Discharge (July 2003) Kelsey Forebay Hourly WSL (July 2003)

602.0

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607.0

608.0

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Date

Kelsey Hourly Total Discharge (July 2003) Sipiwesk Lake Hourly WSL (July 2003)



Figure 4.3.2-24: Total Discharge and Tailrace Water Level at Kelsey Generating Station during Cycling Operation in July 2003

Figure 4.3.2-25: Total Discharge at Kelsey Generating Station and Split Lake Water Level during Cycling Operation in July 2003

544.0

545.0

546.0

547.0

548.0

549.0

550.0

551.0

552.0

0

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Kelsey Hourly Total Discharge (July 2003) Kelsey Tailrace Hourly WSL (July 2003)

542.0

543.0

544.0

545.0

546.0

547.0

548.0

549.0

550.0

0

10000

20000

30000

40000

50000

60000

70000

80000


Split

Lak

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Date

Kelsey Hourly Total Discharge (July 2003) Split Lake Hourly WSL (July 2003)



SIPIWESK LAKE

Water level data for Sipiwesk Lake is only available prior to impoundment of the Kelsey GS forebay during parts of 1952 and 1954. Flow measurements were also taken at a location 4 mi (6.4 km) below Sipiwesk Lake during the 1952 and 1954 hydrometric program (Manitoba Department of Mines and Natural Resources 1952, 1954). Comparing water levels prior to and after Kelsey GS impoundment under similar flow conditions, it appears that the Kelsey GS increased the average water level on Sipiwesk Lake by approximately 10 ft (3.0 m). The Federal Ecological Monitoring Program (FEMP) estimated that that impoundment of the Kelsey GS increased the water level on Sipiwesk Lake by 3.3 to 6.6 ft (1.0 m to 2.0 m) (Environment Canada and Department of Fisheries and Oceans 1992a). In the report titled Post-Project Assessment of Kelsey GS and Lake Winnipeg Regulation Impacts on Wabowden, it is estimated that, prior to the development at Kelsey GS, the long-term median monthly level of Sipiwesk Lake was 596.0 ft (181.7 m) (MacKay et al. 1990). The long-term median monthly level is 610.6 ft (186.1 m) in the available record after 1965.

The available data presented in Figure 4.3.2-26 is divided into years pre- and post-LWR. Similar to the effects on Cross Lake, LWR has reversed the seasonal water level pattern on Sipiwesk Lake in low to average flow years. Based on the available data, it would appear that the average water level on Sipiwesk Lake was higher prior to LWR. However, these higher water levels were the result of flows being approximately 25% higher in the pre-LWR period of record (1965–1976) when compared to the post-LWR period of record (1976–2014). Based on the available record of data, the Sipiwesk Lake average monthly water level variation increased from 0.7 ft (0.2 m) pre-LWR to 1.1 ft (0.3 m) post-LWR. Figure 4.3.2-27 shows the average, historical range and upper and lower quartiles for daily Sipiwesk Lake water levels in the post-LWR period (1976–2014). Water levels during the 2003 drought and 2011 flood are also included on the figure. The 2003 drought resulted in very low Sipiwesk Lake water levels for most of the year, reaching record lows for the last few months of the year. The 2011 flood resulted in record high Sipiwesk Lake water levels for most of the year.

Similar to the Jenpeg GS forebay and Cross Lake, larger water level variations occur on Sipiwesk Lake during transition periods from times when Jenpeg GS is being operated at maximum discharge to times when Jenpeg GS is operated to conserve water in Lake Winnipeg as part of LWR operations. An example was August 2013 when Sipiwesk Lake water levels dropped 4.9 ft (1.5 m) over a period of 1.5 months following flow reductions at Jenpeg GS as Lake Winnipeg dropped below 715 ft (217.9 m). For comparison, this is almost twice the water level drop that occurred on Cross Lake and it took more than twice as long to occur.


Impoundment of the Kelsey GS forebay decreased water velocities between Sipiwesk Lake and Kelsey GS. As a result, rapids areas that used to remain open year round now freeze over with a stable thermal ice cover. Also, in years with large water level variations in the Kelsey GS forebay during the winter, ice conditions may be affected including potentially contributing to slush ice conditions. Lake Winnipeg Regulation results in higher winter flows, which can affect ice conditions in this hydraulic zone and has the potential to contribute to slush ice by increasing water level fluctuations on Sipiwesk Lake.



Figure 4.3.2-26: Monthly Average Sipiwesk Lake Water Levels

Figure 4.3.2-27: Daily Sipiwesk Lake Water Levels

185.0

185.3

185.6

185.9

186.2

186.5

186.8

187.1

187.5

607

608

609

610

611

612

613

614

615


Mon

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Ave

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Sip

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k La

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Lev

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m]

Mon

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Sip

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k La

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Lev

el [

ft]

Month

Pre-LWR 05UD006 (1965-1976) Post-LWR 05UD006 (1976-2014)

55.5

56.1

56.7

57.3

57.9

182.0

184.0

186.0

188.0

190.0


Sipi

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k La

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Lev

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m)

Sipi

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k La

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Lev

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Month




4.3.3 Churchill River Diversion Influenced Zones Following joint federal-provincial studies (Canada and Manitoba 1965), in February 1966 Manitoba Hydro announced its intention to divert the Churchill River as part of an overall plan of northern hydro development. Instead of harnessing the hydroelectric potential by building plants right on the Churchill River, a considerable economic advantage was gained by diverting most of the Churchill River water into the Burntwood and Nelson River systems to use at the generating stations on the lower Nelson River.

Churchill River Diversion is a key feature of hydroelectric development in Manitoba and is responsible for on average 25% of the flow to Manitoba Hydro’s system. Manitoba Hydro controls all outflow from SIL through operations at the Missi Falls CS and Notigi CS. The majority of flow is diverted through Notigi CS, while discharge at both Missi Falls CS and Notigi CS typically remain constant for long periods of up to several months at a time. SIL is used as a seasonal reservoir as it is typically filled during the open water period to store water for use during the winter when the lake is typically drawn down. Operating decisions are made such that flow releases through Notigi CS and Missi Falls CS result in maximized system generation, while staying within applicable CRD Water Power Act Licence limits for flows and water levels. This additional water in the Nelson River is especially important during winter when Lake Winnipeg outflows are restricted by ice. Flow conditions on the Nelson River also influence CRD operating decisions. For example, CRD flows through Notigi CS are sometimes reduced during periods when the Nelson River is experiencing flood conditions. In these instances, water is either stored in SIL (if licence conditions permit) or released at Missi Falls CS into the lower Churchill River.

The Augmented Flow Program is the annually approved deviation from the Churchill River Diversion Water Power Act Licence. It allows Manitoba Hydro to divert more water on average from the Churchill River into the Nelson River. This is accomplished with an increase in allowable discharge at Notigi CS and a wider range of levels at the Notigi forebay and on SIL to provide additional operating flexibility. While it is an annually approved deviation from the CRD Water Power Act Licence, the Augmented Flow Program is an integral part of how CRD is operated today and has been operated for the last 30 years. It is likely how the project would have been designed had there been better winter hydraulic modeling tools available when CRD was developed.

The RCEA ROI includes six hydraulic zones, which are influenced by CRD. These include:

• Hydraulic Zone 4 – Leaf Rapids to SIL; • Hydraulic Zone 5 – Lower Churchill River; • Hydraulic Zone 6 – South Bay Channel to Notigi CS; • Hydraulic Zone 7 – Notigi CS to Early Morning Rapids; • Hydraulic Zone 8 – Early Morning Rapids to Wuskwatim GS; and • Hydraulic Zone 9 – Wuskwatim GS to Split Lake.

Key hydraulic features within each hydraulic zone will be described within the appropriate sections below.



4.3.3.1 Typical Churchill River Diversion Operation Churchill River Diversion operating decisions are made considering water supply conditions and other factors at the time. The following is a broad description of typical CRD operations over the course of a year. It is not meant to be a comprehensive guideline applicable to all possible conditions.

WINTER

In late fall, diversion flow at Notigi CS is typically increased in weekly steps to supply Nelson River generation during the winter when Manitoba load is highest. Flows are typically increased to the maximum (34,000 cfs or 960 cms authorized as part of the Augmented Flow Program under the CRD Water Power Act Licence) if water supply permits, which is dependent on projected lake inflows and the level of SIL. Water levels in the Notigi CS forebay and all the way to and including SIL are typically drawn down throughout the winter.

SPRING

As spring approaches, CRD operations are planned based on current SIL levels, storage levels elsewhere in the system, snowpack, and inflow forecasts. Generally, the objective for spring operation of CRD is to allow SIL to refill with spring runoff while avoiding overloading the lower Nelson River with diversion flow at a time when demand is lower. However, during above average or high water supply conditions in the Churchill River basin, maximum diversion operations may continue through spring and into summer. Missi Falls CS discharge may also be increased above the minimum to avoid SIL from rising above 847.5 ft (258.3 m), which is the maximum authorized water level as part of the Augmented Flow Program under the CRD Water Power Act Licence. In low water supply years, diversion flows are reduced to conserve spring runoff to supply lower Nelson River generation at a later time.

SUMMER

Churchill River Diversion operations during the summer are largely dependent on inflows at the time, which can vary greatly from year to year and can change relatively quickly due to precipitation in the basin. Notigi CS outflow varies from 15,000 to 35,000 cfs (420–990 cms). In years when SIL is full and inflows continue to be strong, excess water is spilled at Missi Falls CS. Also, in years when the Nelson River is experiencing flood conditions due to high Lake Winnipeg outflows, Notigi CS outflows are reduced to avoid aggravating flooding. This can lead to higher outflows at Missi Falls CS.

FALL

During the fall, inflows to SIL typically begin to decrease. If Missi Falls CS outflows have been above minimum during the summer, they would typically be reduced during the fall to avoid drawing down SIL. On the other hand, Notigi CS outflows are typically increased prior to winter as described above to supply Nelson River generation. The level of SIL typically starts to be drawn down in late fall.



AUGMENTED FLOW PROGRAM

During the design of CRD, there were specific water levels at Nelson House and Thompson that were not to be exceeded. This led to the Notigi CS outflow limit in the CRD Water Power Act Licence. After construction was completed, initial operations in 1977 revealed that impacts downstream of Notigi CS in open water were about as expected and ice impacts were much less than expected. This led to a decision to explore higher diversion flows. In 1978, Manitoba Hydro requested approval to test the diversion capacity over a wider range than was set out in the CRD Water Power Act Licence. The following is a summary of the maximum authorized flows during the testing phase: • 1979 – Winter maximum increased from 30,000 to 32,000 cfs (850 to 906 cms); • 1980 – Repeat of 1979; • 1981 – Summer maximum increased from 30,000 to 34,000 cfs (850 to 963 cms); • 1982 – Summer maximum increased to 35,000 cfs (991 cms) (has remained the same to present); • 1983–1985 – Winter maximum increased to 33,000 cfs (934 cms); and • 1986 – Winter maximum increased to 34,000 cfs (963 cms) (has remained the same to present).

After this multi-year testing phase, approvals to deviate from the terms of the CRD Water Power Act Licence have been the same for each winter and summer period since 1986. This mode of operation has become known as the Augmented Flow Program.

Annual approvals since 1986 include the following: • The SIL minimum level is reduced from 844 ft to 843 ft (257.3 m to 256.9 m) and the maximum level

is increased from 847 feet to 847.5 feet (258.2 m to 258.3 m) with a maximum permissible drawdown of 4.5 ft (1.4 m);

• The Notigi CS minimum level is reduced from 838 ft to 834 ft (255.4 m to 254.2 m); and

• The maximum flow limit at Notigi CS is increased from 30,000 cfs to 34,000 cfs (850 cms to 960 cms) during November 1 to May 15 and to 35,000 cfs (990 cms) during May 16 to October 31.

The limit on the Burntwood River flow at Thompson is replaced with a maximum elevation of 619 ft (188.7 m) at the Thompson seaplane base during May 16 to October 31 and 623 ft (189.9 m) at the Thompson pump-house during November 1 to May 15.

While SIL and Notigi CS have been operated over the entire requested ranges in the years since the Augmented Flow Program was established in 1986, operation over the entire range does not occur each year. Further information about the typical amount of drawdown is provided in the sections below.

Although extremely rare, there have been instances when either the Missi Falls CS or Notigi CS has been shut down entirely for a short period. These include events such as emergencies and maintenance inspections. Manitoba Hydro monitors these events closely. An example of a complete shutdown occurred in August 2007 at Notigi CS when the control structure was shut down for a number of hours each day over a four-day period to complete a dam safety inspection. The Notigi CS forebay and Wapisu Lake responded to the hourly operations at the Notigi CS and the maximum daily water level fluctuations were 0.9 and 1.6 ft respectively, however water levels remained within their post-CRD ranges. Upstream, SIL experienced no detectable impact from the flow operations at the Notigi CS. Downstream, the



impacts of hourly operations at Threepoint and Footprint lakes were not noticeable but rather the water levels changed in response to changes in daily average flow.

During the construction of CRD, flow at Notigi Rapids was stopped for a period of about 18 months from May 8, 1974 to November 24, 1975. Pre-CRD flows at Notigi Rapids averaged 1200 cfs (34 cms) (LWCNRSB 1975). This temporarily reduced the average flow in the Burntwood River at Thompson by about 30%.

4.3.3.2 Hydraulic Zone 4 – Leaf Rapids to Southern Indian Lake Hydraulic zone 4 includes the upper Churchill River from Leaf Rapids to SIL (Map 4.3.3-1). Starting from Leaf Rapids, the Churchill River runs approximately 20 mi (32 km) before reaching Opachuanau Lake, which is connected to SIL.

Two of the three main components of the CRD are located in this hydraulic zone. The Missi Falls CS controls the outflow at the natural outlet of SIL and raised the water level on the lake. The South Bay Diversion Channel is an excavated channel from the South Bay of SIL to Issett Lake and creates a new outlet to allow Churchill River water to flow into the Rat River and Burntwood River System. The Notigi CS is the third main component of CRD and is described in Section 4.3.3.4.


Inflows to this hydraulic zone arise mainly from the upper Churchill River. While not regulated by Manitoba Hydro, upper Churchill River flows are regulated further upstream in Saskatchewan for hydroelectric purposes. Outflows from this hydraulic zone are regulated by operation of Missi Falls CS and Notigi CS for SIL outflows at the South Bay Diversion Channel. Impoundment of SIL resulted in a backwater effect up the Churchill River that affects water levels up to the downstream end of Leaf Rapids.

4.3.3.2.2 Data

Water Survey of Canada has been reporting a daily water level record for SIL since 1956 at station 06EC001 (Southern Indian Lake near South Indian Lake); however, the record is less complete in earlier years. Manitoba Hydro also measures water levels in the Missi Falls CS and Notigi CS forebays and has measured discharge through the control structures since 1976.



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AMISK PARKRESERVE

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06EC001

LeafRapids

O-Pipon-Na-PiwinCree Nation

South Indian Lake

Lake

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Turnbull

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Karsakuwigamak

Esker

Nisku

Brehaut

RustyLake

Bay

Lake

Opachuanau

LLake

Fraser

L

Barlow

Enatik

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Issett

Bay

Wasiske

IssetIsland

L

River

Wupaw

Bay

Lemay

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Mistataykamik

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Indian

NarrowsBay

SouthPoplar

Pecheponakun

BaySwan

CousinsLake

Bay

Sandhill

Torrance

Lake

Chapman

LakeUhlman

LNaykownapiskaw

Broughton

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Wapisewsis

WapaykoL

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Paskowapow

Pakeekamak

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1.0

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LegendTownStation GaugeFlow DirectionDiversion (Existing)

First Nation ReservePark (Provincial)Watercourse Boundary (Predevelopment)Watercourse (Existing)RCEA Hydraulic Zone

04-DEC-15

Hydraulic Zone 4Leaf Rapids to Southern Indian Lake

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Map 4.3.3-1



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SAND LAKESPROVINCIAL

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HydraulicZone 4

06EC006 MissiC.S.

Unagimau

KatimewLake

PawakowL

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James

Grandmother

Lake

HurstLake

Denison

Lake

LHendry

Big

Sand

LPidlaski

Stevens

O'Neil

Muskwesi

LakeMacKerracher

LMcPherson

Chipewyan

MatooL

Little

Onaykawow

L River

L

Kapeetaukimak

LAmiskoskotim

L

Muskosiu

River

L

LSedgwick

Sandberg

LNutter

Meehawaneeneek

Pine

Lake

Long

MeestaLoon

L

L

LNitawikew

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Moss

Little

LMuhekunSand

Lake RLake

Sand

Southern

Bay

BlackSmith

Sand

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Narrows

Bear

Pt

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Narrows

Point

Strawberry I

L

Pisew

Ck

Georges

Waddie

PamRiver

Osikis

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LakeSouthClee

Allard

Waddie

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L

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PartridgeBreast

SpenceL Oli L

Thompson

ChurchillHudson

Bay



1.0

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LegendControl Structure (Existing)Station GaugeFlow DirectionDykePark (Provincial)Watercourse Boundary (Predevelopment) Watercourse (Existing)RCEA Hydraulic Zone

04-DEC-15

Hydraulic Zone 4Leaf Rapids to Southern Indian Lake

2 of 2


Map 4.3.3-1




SOUTHERN INDIAN LAKE

Churchill River Diversion increased the average water level on SIL by 9 ft (2.7 m) and increased the water surface area along the Churchill River from Leaf Rapids up to and including SIL from 843 to 898 sq mi (2,180 to 2,330 km2) by flooding approximately 55 sq mi (140 km2) of land. Increased water levels created a backwater effect that influences water levels as far upstream as the outlet of Granville Lake at Leaf Rapids. Granville Lake is not considered an affected waterbody because, based on hydraulic modeling, backwater effects greater than 0.3 ft (0.1 m) have occurred less than 10% of the time (Manitoba Hydro 2010). Backwater effects on Granville Lake only occur when low flow conditions on the upper Churchill River are combined with high water levels on SIL.

Churchill River Diversion also affects flow patterns within SIL. While all of the water used to flow out the natural outlet at Missi Falls, the majority of inflowing water now typically flows south via the South Bay Diversion Channel. Flow patterns within SIL also vary considerably when large spill events occur at Missi Falls CS. These large spill events vary in duration depending on inflows and other factors and can result in fairly rapid increases or decreases in outflow at Missi Falls CS. These large flows changes can change flow patterns within the lake quite rapidly.

As shown in Figure 4.3.3-1, the available data indicates that the seasonal water level pattern on SIL is similar to the pre-CRD pattern. The highest water levels typically still occur during the summer, water levels are still drawn down over the winter and water levels are still typically lowest in spring. Pre-CRD data also includes effects from the Island Falls GS in Saskatchewan which was completed in 1930 and results in higher winter flows than would occur under natural conditions.

Figure 4.3.3-2 shows the average, historical range and upper and lower quartiles for daily water levels on SIL from 1978 to 2014. Over this time frame the average annual drawdown was 3.3 ft (1.0 m), while the minimum and maximum drawdown was 1.1 ft (0.3 m) and 4.7 ft (1.4 m) respectively (using June–May as annual period). Figure 4.3.3-2 also includes the SIL water level during the 2003 drought and 2011 flood on the Nelson River. During the 2003 drought SIL water levels were drawn down closer to the CRD Water Power Act Licence minimum of 843.0 ft (254.2 m) and SIL was only refilled during the subsequent open water season to 845.5 ft (257.7 m), well below normal and well below the CRD Water Power Act Licence maximum of 847.5 ft (258.3 m). In 2011, SIL was refilled close to the upper limit by early August. This was partly because Notigi CS outflows were reduced to avoid aggravating flood conditions on the lower Nelson.

Outflows at Notigi CS and Missi Falls CS are typically held constant for periods of up to several months at a time. When flow changes are made, they are typically staged with weekly adjustments occurring over a period of several weeks. As a result, operation of CRD does not typically cause large hourly or daily water level variations on SIL. As shown in Table 4.3.3-1, the largest daily variations on SIL are typically less than a few inches. Table 4.3.3-1 also provides average and 95th percentile weekly and annual water level variations both pre and post-CRD. Weekly variations have remained similar to pre-CRD, while annual variations have increased on average but remain within the historical range.



Figure 4.3.3-1: Monthly Average Southern Indian Lake Water Levels

CRD = Churchill River Diversion.

Figure 4.3.3-2: Daily Southern Indian Lake Water Levels (Post-CRD)

254.5

255.1

255.7

256.3

256.9

257.6

258.2

258.8

835.0

837.0

839.0

841.0

843.0

845.0

847.0

849.0


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Pre-CRD 06EC001 (1956-1973) Post-CRD 06EC001 (1978-2014)

256.3

256.6

256.9

257.3

257.6

257.9

258.2

258.5

258.8

259.1

841.0

842.0

843.0

844.0

845.0

846.0

847.0

848.0

849.0

850.0


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Sout

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Table 4.3.3-1: Daily, Weekly and Annual Southern Indian Lake (SIL) Water Level Variation at Gauge 06EC001

Variation Pre-CRD 1 Mean (ft)

1956–1973

Post-CRD Mean (ft)

1978–2014

Pre-CRD 95thPercentile (ft)

1956–1973

Post-CRD 95thPercentile (ft)

1978–2014

Daily 0.0 0.0 0.2 0.1

Weekly 0.2 0.1 0.4 0.4

Annual 2.7 3.4 4.2 4.2

Note: Annual variation is max-min in each year June–May. 1. CRD = Churchill River Diversion.

SOUTHERN INDIAN LAKE WATER RESIDENCE TIME

Evidence that residence time varies considerably within SIL can be found in a 1981 study of water budgets for SIL before and after impoundment as a result of CRD (McCullough 1981). This study divided SIL into eight Historical Geographic Areas (HGAs; referred to as SIL Areas 0–7, see Water Quality Map 5.2.8-3) and made a number of assumptions to estimate pre- and post-CRD water residence times for each HGA, as shown in Table 4.3.3-2. Pre-CRD residence times ranged from 0.012 years to 4.2 years between the eight HGAs of the lake. While the average water exchange time for the lake as a whole increased from 0.51 to 0.72 years because of the increased volume of the lake, the post-CRD residence times were found to range between 0.021 and 2.8 years between the eight HGAs. Southern Indian Lake Areas 0, 1, 2, 5, and 7 changed by the least amount since these HGAs were mainly only affected by impoundment. Residence times in SIL Areas 3 and 4 increased the most since much less Churchill River water now flows through these HGAs, while residence time in SIL Area 6 decreased substantially because the diversion flow now flows through this HGA. Even though the above study did break down SIL into eight HGAs and tried to account for local drainage from tributaries, the calculations still make a number of assumptions. The most notable assumptions are that the effects of current and wind-induced mixing are ignored.

As described above, flow patterns within SIL vary considerably when large flow releases are made a Missi Falls CS. In these situations, water residence times also vary considerably, especially in HGAs 3 and 4, which are along the flow path of water flowing through SIL towards Missi Falls CS.

Table 4.3.3-2: Pre- and Post-CRD Water Residence Times for Historical Geographic Areas of Southern Indian Lake

Whole Lake

SIL Area 0 1 2 3 4 5 6 7 Pre-CRD1 Exchange Time (y) 0.51 0.012 0.12 0.053 0.055 0.23 1.5 4.2 0.39

Post-CRD Exchange Time (y) 0.72 0.021 0.17 0.078 0.40 1.4 2.8 0.031 0.73

1. CRD = Churchill River Diversion.




Pre-CRD, the ice cover on SIL was usually formed in late fall and used extensively as a roadbed for winter transportation especially near the settlement at South Indian Lake. Post-CRD, as forecasted by the LWCNRSB, the ice cover near the South Indian Lake Settlement became poor or non-existent (LWCNRSB 1974).

4.3.3.3 Hydraulic Zone 5 – Lower Churchill River Hydraulic Zone 5 covers the lower Churchill River from the Missi Falls CS to the Churchill Weir just upstream from the Churchill River estuary (Map 4.3.3-2). Major lakes in this hydraulic zone include Partridge Breast, Thorsteinson, Northern Indian, and Fidler.


The operation of CRD substantially reduces average inflows to the lower Churchill River from SIL resulting in lower water levels in both the lakes and river sections. Despite the reduction in inflows, high flow conditions still occur in some years on the lower Churchill River and operation of CRD sometimes causes rapid flow increases.

4.3.3.3.2 Data

Water Survey of Canada measures lower Churchill River discharge at two locations in this hydraulic zone. Station 06FB001 (Churchill River below Fidler Lake) and station 06FD001 (Churchill River above Red Head Rapids) have operated since 1960 and 1971 respectively. Manitoba Hydro also monitors discharge entering this hydraulic zone post-CRD at Missi Falls CS


LOWER CHURCHILL RIVER DISCHARGE

Flow releases at Missi Falls CS provide inflows to the upper end of this hydraulic zone. Figure 4.3.3-3 shows the median, historical range and upper and lower quartiles for daily Missi Falls CS discharge from 1978 to 2014. Missi Falls CS discharge during the 2003 drought and 2011 flood on the Nelson River are also included. Missi Falls CS discharge during the 2003 drought followed the minimum allowed under Churchill Weir Environment Act Licence. Missi Falls CS outflows during the 2011 flood peaked well above normal in August–September. The above average discharge was created by a number of factors including high precipitation in the basin and reduced discharge at Notigi CS because of flood conditions on the Nelson River.

.



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AMISK PARKRESERVE

SAND LAKESPROVINCIAL

PARK

HydraulicZone 506EC006

06FB001

MissiC.S.

Southern

Bay

BlackSmith

Sand

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Lake

Torrance

Lake

ChapmanLake

Strawberry I

L

Pisew

Ck

Georges

LakeAllard

Lake

Lake

Lake

PartridgeBreast

SpenceL Oli L

Gauer

Mistutikumak

Thorsteinson

Lake

Lake

BayUmisk

Wood

Wood

Lake

Missinipi

Lake

Hibbert

L

Korney

Northern

Muheekun

Muheekun

River

Meethachos

Wernham L

Yaykow

R

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L

Rapids

Indian

Kirkness

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NaykowLake

SolmundssonLake

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Churchill

Fidler

Lake

Settee

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Thomas

Peekopanik

HolmesLake

Rivière

Pasatayo

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Mimistiko

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Kotchapaw

Garrity

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Little

LPeters

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LakeFreeman

Churchill

MaskoseeL

Thorkelsson

L

PapakeesooLake

Awakamasik

Muhekun

Billard

Lake

L

Shakownipew

Hogg

L

Lake

Beaver

Rusnak

Minikwakunis Lake

Furey

L

Lake

Thompson

ChurchillHudson

Bay



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LegendControl Structure (Existing)Station GaugeFlow DirectionDyke


04-DEC-15

Hydraulic Zone 5Lower Churchill River

1 of 4


Map 4.3.3-2



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NUMAYKOOS LAKEPROVINCIAL PARK

HydraulicZone 5

LittleChurchillRiver

Pasatayo

Alex

Lake

AdamLake

Lake

L

Mimistiko

L

Kotchapaw

Kawakeepinow

Garrity

Lake

Little

LPeters

Lake

LakeFreeman

Churchill

MaskoseeL

Thorkelsson

PapakeesooLake

Billard

Lake

L

Shakownipew

Hogg

L

Lake

Beaver

Rusnak

River

Minikwakunis Lake

Furey

L

Embelton

Lake

Lake

Rapids

River

Mountain

River

LakeComeau

SwallowRapids

River

WhitingLake

DeerLakes

LakeBradshaw

TurcotteLake

MiniayLake

LakeLong

Lake

Mistake

Lake

Lake

Fly

Owl

Owl

Thompson

ChurchillHudson

Bay



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07-DEC-15


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Map 4.3.3-2



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WAPUSKNATIONAL PARK

OF CANADA

WILDLIFEMANAGEMENT

AREA

NUMAYKOOS LAKEPROVINCIAL PARK

HydraulicZone 5

06FD001

Matonabee

LakeGresham

River

LakeComeau

Numaykoos

Lake

MackLake

L

Knight

WiseL

Braden

Lake

Churchill

LakeBradshaw

Chasm

Herriot

Robson

Ck

Crosswell

Creek

Laforte

Rapids

Red Head

Limestone

Creek Rapids

RunningLandingPlace

Rapids

River

River

Deer

Dog

River

Lake

Lovett

MarantzL

L Lake

Fletcher

Lake

Kelsey

Beale

Hoot

Thompson

ChurchillHudson

Bay



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LegendStation GaugeFlow DirectionWildlife Management AreaPark (National)Park (Provincial)Watercourse Boundary (Predevelopment)Watercourse (Existing)

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07-DEC-15


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WAPUSKNATIONAL PARK

OF CANADA

WILDLIFEMANAGEMENT

AREA

HydraulicZone 5

ChurchillWeir

Churchill

Creek

Creek

Knife

Langille

L

RiverDickens

Herriot

Falls

Teepee

Creek

River

Nowell

Lake

Creek

Lake

Lofthouse

Rankine

L

Heppell

Bishop

L

Limestone

Creek

Munk

LPelletier

Holcroft

DymondL

ButtonBay

Wales Pt

Eskimo Pt

Lake

Creek

River

Long I

River

Rapids

Running Landing

Creek

Warkworth

Alston

Lake

Lake

Warkworth

Goose

Ck

Farnworth

StyggeL

Cove

Bird

Lake

Christmas

Lake

McQueen

Norton

Lake

Ritchie

Lake

Lakes

Twin

Mast

Creek

SteelePert

L Lake

Fletcher

Lake

Numaykoos

L

LakeHannah

Sutton

LBrown

Lake

Klohn

Mary

River

Watson

Bay

PtLa Perouse

Napper

L

Lake

Thompson

ChurchillHudson

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RCEA Hydraulic Zone

07-DEC-15


4 of 4


Map 4.3.3-2



On average, 27,700 cfs (780 cms) is diverted from the Churchill River system into the Nelson River system at SIL. This reduction in flow along the lower Churchill River has resulted in lower water levels and 78.6 sq mi (203.7 km2) of dewatered area. Flow contributions from the remainder of the Churchill River basin between Missi Falls CS and Hudson Bay are such that average flow below Fidler Lake is 9,200 cfs (260 cms) and above Red Head Rapids is 12,900 cfs (370 cms). Figures 4.3.3-4 and 4.3.3-5 show that river discharge pre- and post-CRD has a similar seasonal pattern with peaks occurring during the open water season and the lowest flows observed during the winter.

Based on simulated conditions with and without CRD presented in Appendix 4.3B, the average water levels of Partridge Breast, Northern Indian, Fidler and Billard Lakes have dropped by 13.5 ft (4.1 m), 7.6 ft (2.3 m), 15.1 ft (4.6 m) and 9.2 ft (2.8 m) respectively. The simulation also estimates that the percentage of flow at Red Head Rapids originating from Missi Falls was 46% with CRD and would have been 83% without CRD.

Figures 4.3.3-6 and 4.3.3-7 show the median, historical range and upper and lower quartiles for daily flow below Fidler Lake and above Red Head Rapids from 1978 to 2014. Both figures show that high flows still occur in some years although very infrequently. The figures also show flows that occurred during the 2003 drought and 2011 flood. In 2003, the flow on the Churchill River below Fidler Lake remained near record low for most of the year while further downstream above Red Head Rapids had similar flow conditions except for a short peak above the upper quartile in May. In 2011, flows were closer to normal and peaked at both locations in August–September because of high Missi Falls CS discharge, which was influenced by flood conditions on the Nelson River as described above.


Figure 4.3.3-3: Daily Missi Falls ControlStructure Discharge (Post-CRD)

0.0

283.2

566.3

849.5

1,132.7

1,415.8

1,699.0

1,982.2

2,265.3

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000


Mis

si F

alls

Dis

char

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cms)

Mis

si F

alls

Dis

char

ge (

cfs)

Month

Range 1978-2014 Median 1978-2014 Lower quartileUpper quartile 2011 2003



Figure 4.3.3-4: Monthly Average Churchill River below Fidler Lake Discharge

Figure 4.3.3-5: Monthly Average Churchill River above Red Head Rapids Discharge

0

283

566

850

1,133

1,416

1,699

0

10000

20000

30000

40000

50000

60000


Chu

rchi

ll R

iver

Bel

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r Lak

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isch

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[cm

s]

Chu

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ll R

iver

Bel

ow F

idle

r Lak

e D

isch

arge

[cf

s]

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Pre-CRD 06FB001 (1960-1975) Post-CRD 06FB001 (1978-2012)

0

283

566

850

1,133

1,416

1,699

0

10000

20000

30000

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Chu

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Rap

ids

Dis

char

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cfs]

Month

Pre-CRD 06FD001 (1971-1975) Post-CRD 06FD001 (1978-2014)




Figure 4.3.3-6: Daily Churchill River below Fidler Lake Discharge (Post-CRD)


Figure 4.3.3-7: Daily Churchill River above Red Head Rapids Discharge (Post-CRD)

0

283

566

850

1,133

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1,982

2,265

2,549

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2,832

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CHURCHILL WEIR

The Churchill Weir is a structure designed to mitigate CRD effects by increasing water levels on the Churchill River to facilitate a potable water source and to enhance recreation and aquatic habitat. The structure was built 6.21 mi (10 km) south of the Town of Churchill, just upstream of Mosquito Point. The structure consists of an overflow section and two dyke sections. The overflow section also features a fishway segment at the lowest point of the weir. The east dyke incorporates the Goose Creek fishway and an emergency flood relief section. These works were completed in October 1999.

The physical performance of the weir was evaluated between 1999 and 2008 using water level information collected by Manitoba Hydro and WSC. Analyses indicated that the water level has increased by approximately 6.6 ft (2.0 m) near the weir and the water level at the CR30 Pumphouse has risen by about 3.3 ft (1.0 m). The elevated water level effects extend upstream from the weir for a distance of at least 6.2 mi (10 km).

LOWER CHURCHILL RIVER WATER RESIDENCE TIME

As part of LWCNRSB work in 1975, pre and post-CRD water residence times were estimated for three lakes downstream from Missi Falls on the lower Churchill River. Residence time was estimated to increase from 1.7 to 4.8 years in Partridge Breast Lake, increase from 9 to 16.4 years in Northern Indian Lake, and remain the same at 1.3 years in Fidler Lake (LWCNRSB 1975).

In general, water residence time would likely have increased along much of the lower Churchill River because of the reduced flow. Water residence time would have also been further increased near Churchill just upstream from the Churchill Weir after its construction in 1999 because of impoundment.


Churchill River Diversion resulted in reduced winter discharge and reduced water velocities along the lower Churchill River. Lower velocities result in increased area with ice cover. There would also be less ice accumulation by shoving and thickening at the leading edge which typically occurs downstream of fast flowing open water river sections.

4.3.3.4 Hydraulic Zone 6 – South Bay Channel to Notigi Control Structure

This hydraulic zone covers the Rat River system from the excavated outlet at the South Bay of SIL to the Notigi CS (Map 4.3.3-3). Major lakes in this hydraulic zone include Issett, Rat, and Notigi.

The Notigi CS is the third main component of CRD. It is a control structure on the Rat River that regulates the diversion flow from SIL into the Burntwood-Nelson River system. The other components of CRD, including the Missi Falls CS and the South Bay Diversion Channel, are described in Section 4.3.3.2.



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05TF001

NotigiC.S.

NisichawayasihkCree Nation

NelsonHouse (NAC)

Highrock

Lake

Ck

Lake

DevilFalls

Granville

Rapids

Bay

Asowi

NewunetanLake

L

Nelson

Wupas

Suwannee

Lake

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Suwannee

Costello

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PontiusL

Lake

Goodwin

River

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Atik

Rat

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Rat

Karsakuwigamak

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Misinagu

Notigi

Wapisu

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Mynarski

Lakes

Lake

EarpLivingston

KinwawLake

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L

FootprintLittle

LakeNileLake

Osik

Macheewin

L

KawaweewiL

Footprint

Lake

L

Honeymoon

L

Lake

Mooswuchi

Gramme

Leftrook

R

Walesiak

Lake

Anderson

L

Pecheponakun L

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Worm

Wasakumik

L

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First Nation ReserveWatercourse Boundary (Predevelopment)Watercourse (Existing)RCEA Hydraulic Zone

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Hydraulic Zone 6South Bay Diversion Channel

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South BayDiversionChannel

AMISK PARKRESERVE

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LeafRapids

MuskekoL

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Eden

LakeStag

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Granville

Rapids Suwannee

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Outlaw

LScotland

Alto

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Rat

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Esker

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RustyLake

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Opachuanau

Issett

Bay

Wasiske

IssetIsland

L

Rat

Mynarski

Lakes

Lake

Earp

River

WupawBay

NarrowsBay

SouthPoplar

Livingston

KinwawLake

Lake

Lake

Gramme

Leftrook

R

Walesiak

Lake

Anderson

L

Pecheponakun

BaySwan

LakeUhlman

LNaykownapiskaw

Broughton

L

Wapisewsis

Wapayko

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River

Harding

L

Lake

Worm

Wasakumik

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Pakwaw

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Hydraulic Zone 6South Bay Diversion Channel

to Notigi Control Structure

2 of 2


Map 4.3.3-3




Operation of the Notigi CS regulates both inflows to and outflows from this hydraulic zone. As part of CRD, Manitoba Hydro controls outflow through Notigi CS, which ultimately affects the amount of water entering and flowing through this hydraulic zone. Inflows to this hydraulic zone originate mainly from SIL through the South Bay Diversion Channel.

4.3.3.4.2 Data

Manitoba Hydro maintains a record of daily water levels in the Notigi CS forebay since just before impoundment in 1974. There are four months of continuous data from January to April 1974 in this area prior to first impoundment. Manitoba Hydro has also monitored discharge through Notigi CS since CRD began operation.


ISSET LAKE, RAT LAKE, NOTIGI CONTROL STRUCTURE FOREBAY AREA

The majority of flooding because of the CRD Project occurred in this hydraulic zone. Increased flows through the area and increased water levels because of impoundment upstream from the Notigi CS caused 175 sq mi (453 km2) of flooding. Based on limited data before impoundment of Notigi CS forebay, it appears that CRD increased water levels by approximately 50 ft (15.2 m) just upstream from the Notigi CS. The mean monthly post-CRD water level in Notigi CS forebay has ranged between 834.5 and 847.3 ft (254.4 and 258.3 m), while the seasonal pattern has been to peak in late summer and decline throughout the winter (Figure 4.3.3-8). Figure 4.3.3-9 shows the average, historical range and upper and lower quartiles for daily water levels in the Notigi CS forebay from 1978 to 2014. Over this timeframe, the average seasonal drawdown was 7.2 ft (2.2 m), while the minimum and maximum drawdown was 1.9 ft and 12.8 ft (0.6 m–3.9 m) respectively. Figure 4.3.3-9 also shows the Notigi CS forebay level during the 2003 drought and the 2011 flood. In both years water levels continued to follow the typical seasonal pattern with 2003 water levels below average and 2011 levels above average during the open water season.

Mean monthly discharge at Notigi CS has ranged between approximately 14,000 cfs and 35,000 cfs (400 and 990 cms). Figure 4.3.3-10 shows that Notigi CS discharge is typically higher in the winter months and lower in the spring and summer. Figure 4.3.3-11 shows that 70% of the time Notigi CS discharge has been between 25,000 cfs and 35,000 cfs (710 and 990 cms). Figure 4.3.3-12 shows the average, historical range and upper and lower quartiles for daily Notigi CS discharge from 1978 to 2014. Notigi CS discharge during the 2003 drought and 2011 flood years is also included in the figure. In both instances, Notigi CS discharge was below average during most of the open water season with lower flows occurring in 2011 to avoid aggravating flooding on the lower Nelson River. During the winter season, Notigi CS discharge was at the CRD Water Power Act Licence maximum (34,000 cfs) during the 2011 flood while winter outflow was generally below average during the 2003 drought.



Figure 4.3.3-8: Monthly Average Notigi Control Structure Forebay Water Level


Figure 4.3.3-9: Daily Notigi Control Structure Forebay Water Level (Post-CRD)

254.5

255.1

255.7

256.3

256.9

257.6

258.2

258.8

835

837

839

841

843

845

847

849


Mon

thly

Ave

rage

Not

igi C

S Fo

reba

y W

ater

Lev

el [

m]

Mon

thly

Ave

rage

Not

igi C

S Fo

reba

y W

ater

Lev

el [

ft]

Month

Post-CRD (1978-2014)

256.3

256.6

256.9

257.3

257.6

257.9

258.2

258.5

258.8

259.1

832.0

834.0

836.0

838.0

840.0

842.0

844.0

846.0

848.0

850.0


Not

igi F

oreb

ay W

ater

Lev

el (

m)

Not

igi F

oreb

ay W

ater

Lev

el (

ft)

Month

Range 1978-2014 Average 1978-2014 Lower quartile




Figure 4.3.3-10: Monthly Average Notigi Control Structure Discharge

Figure 4.3.3-11: Notigi Control Structure Discharge Duration Curve

425

566

708

850

991

1,133

15000

20000

25000

30000

35000

40000


Mon

thly

ave

rage

Not

igi C

S D

isch

arge

[cm

s]

Mon

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Not

igi C

S D

isch

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[cf

s]

Month

Post-CRD (1978-2014)

0

142

283

425

566

708

850

991

1,133

0

5000

10000

15000

20000

25000

30000

35000

40000

0 10 20 30 40 50 60 70 80 90 100

Not

igi D

isch

arge

[cm

s]

Not

igi D

isch

arge

[cf

s]


All Data (1978-2014)




Figure 4.3.3-12: Daily Notigi Control Structure Discharge (Post-CRD)

Outflows at Notigi CS are typically held constant for periods of up to several months at a time. When flow changes are made, they are typically staged with weekly adjustments occurring over a period of several weeks. As a result, operation of CRD does not typically cause large hourly or daily water level variations in the Notigi CS forebay area. As shown in Table 4.3.3-3, the largest daily variations in the Notigi CS forebay are typically less than a few inches. Table 4.3.3-3 also provides mean and 95th percentile weekly and annual water level variations.

Table 4.3.3-3: Daily, Weekly and Annual Notigi Control Structure Forebay Water Level Variation

Variation Post-CRD 1

Mean (ft)

1978–2014

Post-CRD 95th Percentile (ft)

1978–2014

Daily 0.1 0.2

Weekly 0.3 0.7

Annual 7.2 11.2


0

142

283

425

566

708

850

991

1,133

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000


Not

igi D

isch

arge

(cm

s)

Not

igi D

isch

arge

(cf

s)

Month




SOUTH BAY TO NOTIGI CONTROL STRUCTURE WATER RESIDENCE TIMES

A 1984 report estimated pre and post-CRD water residence times for lakes along the diversion route between SIL and Notigi CS as shown in Table 4.3.3-4 (Newbury et al. 1984).

Table 4.3.3-4: Pre and Post-CRD Water Residence Times for Lakes between Southern Indian Lake and Notigi Control Structure (CS)

Pre-CRD 1 Post-CRD

Karsakawigimak

Lake Pemichigamau

Lake Central

Mynarski Lake

West Mynarski

Lake

Rat Lake

Notigi Lake

Notigi CS reservoir

Water Renewal Time (days)

37 39 136 213 60 30 62

1. CRD = Churchill River Diversion.


Churchill River Diversion resulted in an increase of water level upstream of Notigi CS, thus reducing the water velocity in most upstream areas and changing ice cover formation during the winter. Immediately upstream of Notigi CS, velocities are higher and an open water area exists throughout the winter.

4.3.3.5 Hydraulic Zone 7 – Notigi Control Structure to Early Morning Rapids

Hydraulic Zone 7 covers the Rat/Burntwood River system from the Notigi CS to Early Morning Rapids (Map 4.3.3-4). Major lakes in this hydraulic zone include Wapisu Lake, Threepoint Lake, Footprint Lake and Osik Lake.


Manitoba Hydro operation of CRD, specifically Notigi CS, regulates the inflow to the upper end of this hydraulic zone. This hydraulic zone is upstream of the water level influence from the Wuskwatim GS. CRD resulted in substantially higher flows in this hydraulic zone and therefore increased water levels above the natural range. The operation of Notigi CS has resulted in a reversal of seasonal flow patterns depicted by higher flows during the winter than in summer (Figure 4.3.3-10). Higher water levels also created a backwater effect up the Burntwood River to Gate Falls and up the Footprint River to Osik Lake. From the Notigi CS to the inlet of Split Lake (Hydraulic zones 7, 8, and 9), The CRD flooded 31.6 sq mi (81.8 km2) of land.



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Lake

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FootprintLittle

LakeNileLake

Osik

Macheewin

L

KawaweewiL

Footprint

Threepoint

Lake

Lake

Wuskwatim

Brook

Lake

L

Honeymoon

L

Lake

Mooswuchi

Leftrook

R

LWorm

Wasakumik

L

River

Sapocheetakaw

Burntwood

WuskwatimFalls

TaskinigupFalls

Ospwagan

River

LUpper

L

Opegano

Lake

Birch

Ospwagan

Burr

Lake

Tree

Wapawukaw

LakeMuskego

R

HunterJock

LL

BirchTree

Lake

Brook

Bailey

LOwl

Nichols

Lake

L

WuskwatimG.S.


NelsonHouse (NAC)

Thompson

ChurchillHudson

Bay



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LegendTownGenerating Station (Existing)Control Structure (Existing)Station GaugeFlow DirectionDyke


07-DEC-15

Hydraulic Zone 7Notigi Control Structure to

Early Morning Rapids 1 of 1


Map 4.3.3-4



4.3.3.5.2 Data

The only continuous water level data available in this hydraulic zone prior to operation of CRD is located at Footprint Lake station 05TF001, which has been operated by WSC since 1960. Water levels have also been collected post-CRD in Wapisu Lake 3.1 mi (5 km) downstream from Notigi CS at station 05TF701 since 1978.


WAPISU LAKE

Wapisu Lake is located directly downstream from the Notigi CS. Figure 4.3.3-13 shows the average, historical range and upper and lower quartiles for daily water levels on Wapisu Lake from 1978 to 2014. Over this timeframe, the average seasonal drawdown was 6.4 ft (1.95 m), while the minimum and maximum drawdown was 1.8 ft (0.55 m) and 9.9 ft (3.02 m) respectively. Figure 4.3.3-13 also shows that Wapisu Lake water levels during the 2003 drought and 2011 flood were fairly similar. In both cases, water levels were highest in the winter and reached extremely low levels during the open water season. In 2003 low levels were caused by low precipitation in the Churchill River drainage basin, while in 2011 low levels were caused by reduced outflow at Notigi CS to avoid aggravating flood conditions on the lower Nelson River. Based on simulated conditions with and without CRD presented in Appendix 4.3C, CRD increased the average water level on Wapisu Lake by about 18.7 ft (5.7 m).


Figure 4.3.3-13: Daily Wapisu Lake Water Level (Post-CRD)

240.8

241.4

242.0

242.6

243.2

243.8

244.4

245.1

245.7

790.0

792.0

794.0

796.0

798.0

800.0

802.0

804.0

806.0


Wap

isu

Lake

Wat

er L

evel

(m

)

Wap

isu

Lake

Wat

er L

evel

(ft

)

Month




FOOTPRINT LAKE

Analysis of the available data indicates that CRD raised the average water level of Footprint Lake by 14.3 ft (4.4 m), from 782.3 ft to 796.6 ft (238.4 m to 242.8 m).

Figure 4.3.3-14 shows that CRD changed the seasonal pattern so that higher water levels typically now occur in the winter while they used to occur during the summer. Figure 4.3.3-15 shows that 90% of the time the pre-CRD range of water levels was 8.3 ft (2.5 m), while post-CRD the range has been reduced to 6.8 ft (2.1 m). The monthly average water level variation on Footprint Lake also reduced from 1.2 ft (0.4 m) pre-CRD to 0.9 ft (0.3 m) post-CRD.

Figure 4.3.3-16 shows the average, historical range and upper and lower quartiles for daily water levels on Footprint Lake from 1978 to 2014. Figure 4.3.3-16 also shows that Footprint Lake water levels during the 2003 drought and 2011 flood were fairly similar. In both cases, water levels were highest in the winter and reached extremely low levels during the open water season. In 2003 low levels were caused by low precipitation in the Churchill River drainage basin, while in 2011 low levels were caused by reduced outflow at Notigi CS to avoid aggravating flood conditions on the lower Nelson River.

Operation of CRD does not cause large hourly or daily water level variations on Footprint Lake. As shown in Table 4.3.3-5, the largest daily variations are typically less than a few inches. Table 4.3.3-5 also provides mean and 95th percentile weekly and annual water level variations both pre and post-CRD. The CRD has not changed weekly variations but has reduced annual variations.

Figure 4.3.3-14: Monthly Average Footprint Lake Water Level

237.1

237.7

238.4

239.0

239.6

240.2

240.8

241.4

242.0

242.6

243.2

243.8

778

780

782

784

786

788

790

792

794

796

798

800


Mon

thly

Ave

rage

Foo

tpri

nt L

ake

Wat

er L

evel

[m

]

Mon

thly

Ave

rage

Foo

tpri

nt L

ake

Wat

er L

evel

[ft

]

Month

Pre-CRD 05TF001 (1960-1976) Post-CRD 05TF001 (1976-2014)



Figure 4.3.3-15: Footprint Lake Water Level Duration Curve


Figure 4.3.3-16: Daily Footprint Lake Water Levels (Post-CRD)

236.2

236.8

237.4

238.0

238.7

239.3

239.9

240.5

241.1

241.7

242.3

242.9

243.5

244.1

244.8

245.4

775

777

779

781

783

785

787

789

791

793

795

797

799

801

803

805

0 10 20 30 40 50 60 70 80 90 100

Foot

prin

t Lak

e W

ater

Lev

el [

m]

Foot

prin

t Lak

e W

ater

Lev

el [

ft]


Pre-CRD 05TF001 (1960-1976) Post-CRD 05TF001 (1976-2014)

240.5

241.1

241.7

242.3

242.9

243.5

244.1

789.0

791.0

793.0

795.0

797.0

799.0

801.0

803.0


Foot

prin

t Lak

e W

ater

Lev

el (

m)

Foot

prin

t Lak

e W

ater

Lev

el (

ft)

Month

Range 1978-2014 Average 1978-2014 Lower quartile




Table 4.3.3-5: Daily, Weekly and Annual Footprint Lake Water Level Variation at Gauge 05TF001

Variation Pre-CRD 1 Mean (ft)

1960–1976

Post-CRD Mean (ft)

1978–2014

Pre-CRD 95th Percentile (ft)

1960–1976

Post-CRD 95th Percentile (ft)

1978–2014

Daily 0.1 0.0 0.2 0.2

Weekly 0.3 0.3 0.9 0.9

Annual 7.5 5.5 10.3 7.7



Higher flows created by CRD in this hydraulic zone resulted in higher velocities along part of the Burntwood River, which may result in areas remaining ice free for longer periods. The Wuskwatim Environmental Impact Statement (EIS) contains a detailed description of ice conditions along the Burntwood River in this hydraulic zone (Manitoba Hydro and Nisichawayasihk Cree Nation [NCN] 2003).

4.3.3.6 Hydraulic Zone 8 – Early Morning Rapids to Wuskwatim Generating Station

Hydraulic Zone 8 covers the portion of the Burntwood River between Early Morning Rapids and the Wuskwatim GS, which includes Wuskwatim Lake (Map 4.3.3-5). The Wuskwatim GS was completed in 2012 and is owned by the Wuskwatim Power Limited Partnership, a legal entity involving NCN and Manitoba Hydro.


Churchill River Diversion operations cause increased flows and water levels, flooding 28 km2 (11 sq mi) in this hydraulic zone. Also, because inflows from Notigi CS are typically higher in the winter as shown in Figure 4.3.3-10, CRD resulted in a seasonal change where water levels are now typically higher along the Burntwood River during the winter. Before CRD, water levels were highest in the summer. Operation of Wuskwatim GS affects water levels as far upstream as the downstream end of Early Morning Rapids.

4.3.3.6.2 Data

There is no continuous data available for this hydraulic zone prior to operation of CRD. Water Survey Canada reports a water level on Wuskwatim Lake since 1995 at station 05TF006 (Wuskwatim Lake near Thompson). Manitoba Hydro now monitors the water level of Wuskwatim Lake as part of operating the Wuskwatim GS.



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NelsonHouse (NAC)

WuskwatimG.S.

Apekakumewsik

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LEyinatik

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Wapisu

River

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Osik

L

KawaweewiL

Footprint

Threepoint

Lake

Lake

Wuskwatim

Wuskwatim

Brook

Lake

L

Honeymoon

LMooswuchi

River

Sapocheetakaw

Burntwood

WuskwatimFalls

TaskinigupFalls

Taylor

Ck

Lake

Ospwagan

River

Joey

LUpper

L

Opegano

Lake

Birch

Ospwagan

Burr

Lake

Tree

HunterJock

LL

BirchTree

Lake

Brook

BaileyL

LOwl

Nichols

Paint

Lake

L

River

Wintering

Lake

GrassRiver

Mystery

Moak

Lake

Lake

ApussigamasiThompson

ChurchillHudson

Bay



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LegendTownGenerating Station (Existing)Control Structure (Existing)Station GaugeFlow DirectionDyke


07-DEC-15

Hydraulic Zone 8Early Morning Rapids to

Wuskwatim Generating Station1 of 1


Map 4.3.3-5




WUSKWATIM GENERATING STATION AND LAKE

Based on simulated conditions with and without CRD presented in Appendix 4.3C, CRD increased the average water level on Wuskwatim Lake by about 10.2 ft (3.1 m).

The Wuskwatim GS has a Licence under The Environment Act and The Water Power Act, which place operational limits on water levels on Wuskwatim Lake. Wuskwatim was the first generating station in Manitoba to be authorized under The Environment Act.

Impoundment of the Wuskwatim forebay resulted in less than 0.5 km2 (0.2 sq mi) of flooding between Wuskwatim Lake and the generating station. Operation of the Wuskwatim GS eliminated the seasonal variance of water levels on Wuskwatim Lake as water levels are kept within a 0.25 m (0.8 ft) range between 233.75 m and 234.0 m (766.9 ft and 767.7 ft) as required by The Environment Act Licence. Water levels on Wuskwatim Lake ranged 1.8 m (5.8 ft) from 232.7 m to 234.4 m (763.3 ft to 769.1 ft) prior to construction of the Wuskwatim GS but post-CRD. The water regime section of the Wuskwatim EIS contains more detailed information on conditions before and after construction of Wuskwatim (Manitoba Hydro and NCN 2003).

The last unit of the Wuskwatim GS went into service in late 2012. In the two years of operation at Wuskwatim, 2013 and 2014, the units were cycled about 80% of the time. Cycling can vary the total station discharge by up to about 710 cms (25,000 cfs) within a day.

While there is no limitation on the amount that the total station discharge can vary in any day, there are upper and lower limits on the water levels immediately upstream on Wuskwatim Lake as follows: • the Wuskwatim Mean Daily Water Level (with wind and wave effects eliminated) cannot exceed 234.0

m (767.7 ft); and

• the Wuskwatim Hourly Water Level cannot exceed 234.1 m (768.0 ft) more than two times for two consecutive hours each time in any 24-hour period;

• the Wuskwatim Mean Daily Water Level (with wind and wave effects eliminated) cannot recede below 233.75 m (766.9 ft); and

• the Wuskwatim Hourly Water Level cannot recede below 233.65 m (766.6 ft) more than two times for two consecutive hours each time in any 24-hour period.

In 2013 and 2014, hourly water levels immediately downstream from Wuskwatim varied by less than 0.5 m (1.64 ft) 95% of time, while the range in hourly water levels within a day varied up to a maximum of 3.0 m (9.8 ft). In order to meet the requirements of The Environment Act Licence, Wuskwatim GS is operated so that daily water level variations on Birch Tree Lake, about 32.2 km (20 mi) downstream from Wuskwatim, are less than 0.10 m (0.3 ft) and 0.15 m (0.5 ft) in open water and winter conditions (wind and wave effects eliminated) respectively.



WUSKWATIM GENERATING STATION CYCLING

From July 15 to August 15 in 2013, Wuskwatim was cycled continuously with total station discharge at approximately 1,050 cms (37,080 cfs) during the day and 350 cms (12,360 cms) overnight. This period was selected because it provides an estimate of the largest water level variations that occur because of cycling operation at Wuskwatim. Figure 4.3.3-17 shows that during this time period, Wuskwatim Lake varied by about 0.2 m (0.7 ft) each day between 233.75 and 233.95 m (766.9 ft and 767.6 ft). As indicated in the Wuskwatim EIS, water level variations diminish upstream from Wuskwatim Lake and do not progress upstream of Early Morning Rapids (Manitoba Hydro and NCN 2003).

Figures 4.3.3-18 to 4.3.3-20 show the effects of cycling at Wuskwatim in Hydraulic Zone 9. Figure 4.3.3-18 shows that water levels varied by up to 2.7 m (8.9 ft) immediately downstream from Wuskwatim because of the cycling operation from July 15 to August 15, 2013. About 12.9 km (8.0 mi) downstream on Opegano Lake, the water level variation is reduced to about 1.0 m (3.3 ft) as shown in Figure 4.3.3-19. Figure 4.3.3-20 shows that about 32.2 km (20 mi) downstream on Birch Tree Lake, the water level variation is reduced to about 0.2 m (0.7 ft). Daily water level variations during this time were less than 0.1 m (0.3 ft).

Figure 4.3.3-17: Wuskwatim Generating StationDischarge and Wuskwatim Lake Water Level during Cycling Operation in July–August 2013

231.0

231.5

232.0

232.5

233.0

233.5

234.0

234.5

235.0

0

200

400

600

800

1000

1200

1400

1600

15-Jul 22-Jul 29-Jul 5-Aug 12-Aug

Wus

kwat

im F

oreb

ay W

ater

Lev

el [

m]

Wus

kwat

im T

otal

Dis

char

ge [

cms]

Date

Wuskwatim Hourly Total Discharge (2013) Wuskwatim Lake Hourly WSL (2013)



Figure 4.3.3-18: Total Discharge and Wuskwatim Generating Station Tailwater Level during Cycling Operation in July–August 2013

Figure 4.3.3-19: Total Wuskwatim Generating Station Discharge and Opegano Lake Water Level July–August 2013

204.0

205.0

206.0

207.0

208.0

209.0

210.0

211.0

212.0

213.0

214.0

0

200

400

600

800

1000

1200

1400

1600

1800

2000


Wus

kwat

im T

ailr

ace

Wat

er L

evel

[m

]

Wus

kwat

im T

otal

Dis

char

ge [

cms]

Date

Wuskwatim Hourly Total Discharge (2013) Wuskwatim Hourly Tailrace WSL (2013)

204.5

205.0

205.5

206.0

206.5

207.0

207.5

208.0

208.5

209.0

209.5

0

200

400

600

800

1000

1200

1400

1600

1800

2000


Ope

gano

Lak

e W

ater

Lev

el [

m]

Wus

kwat

im T

otal

Dis

char

ge [

cms]

Date

Wuskwatim Hourly Total Discharge (2013) Opegano Lake Continuous WSL (2013)



Figure 4.3.3-20: Total Wuskwatim Generating Station Discharge and Birch Tree Lake Water Level July–August 2013


Higher flows created by CRD in this hydraulic zone resulted in higher velocities along parts of the Burntwood River, which may result in areas remaining ice free for longer periods. The Wuskwatim EIS contains a detailed description of ice conditions along the Burntwood River and any effects of the Wuskwatim GS (Manitoba Hydro and NCN 2003).

4.3.3.7 Hydraulic Zone 9 – Wuskwatim Generating Station to Split Lake Inlet

This hydraulic zone covers the portion of the Burntwood River downstream from the Wuskwatim GS to the inlet of Split Lake (Map 4.3.3-6). Major lakes in this hydraulic zone include Opegano, Ospwagan, Birch Tree, Mystery, and Apussigamasi.


Manitoba Hydro operation of CRD regulates the inflow to this hydraulic zone, which is the main driver for water levels. CRD causes substantially higher flows in this hydraulic zone and has therefore increased water levels above the natural range, flooding 20.2 sq mi (52.3 km2) of land. Wuskwatim GS operations also contribute to water level fluctuations as far downstream as Birch Tree Lake (Manitoba Hydro and NCN 2003).

195.4

195.6

195.8

196.0

196.2

196.4

196.6

196.8

197.0

197.2

197.4

0

200

400

600

800

1000

1200

1400

1600

1800

2000


Bir

ch T

ree

Lake

Wat

er L

evel

[m

]

Wus

kwat

im T

otal

Dis

char

ge [

cms]

Date

Wuskwatim Hourly Total Discharge (2013) Birch Tree Lake Hourly WSL (2013)

hydraulic zone 2 - manitoba hydro€¦ · and modified the lake’s main outlet channels by filling...

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