ENSC502 05-06 Living With Our Rivers BRBC Combined

7/28/2019 ENSC502 05-06 Living With Our Rivers BRBC Combined

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Flood 2005: Lessons Learned

ENVIRONMENTAL SCIENCE 502

Susan

Ryan

Presented by Kelly Carter and Ryan WillsonJ une 14, 2006


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ENSC401 Field School IENSC501 Field School IIENSC502 Special Projects in Environmental ManagementENSC503 - Environmental Assessment and Hearings

ENSC 502 students 2005-2006A.Beal, K. Beyak, K. Carter, S. D'Abadie, S. Durham, E. Fulowski, C. Greene,K. Harris, T. Hirsche, E. J ohanson, T. Lesack, J . Martin, J . Migdal, D. Nalley,M. Panek, A. Pfliger, N. Poon, J . Purcell, G. Rokosh, S. Roome-Sandrin,E. Savard, D. Stein, E. Swerdfeger, M. Towey, and R. Willson.

Project Mentors L. Henderson, W. Holden, D. Iredale, M. Iwanyshyn,D. Nuell, and C. Ryan.

B.Sc. Environmental Science Program



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Flood 2005: Lessons Learned

Hydrologic Aspects of Elbow River Watershed Flooding

Bow River Ecological Changes Following Flood 2005

Surface Water Quality Changes During Flooding

Spatial distribution of Flood Damage in Rideau and Roxboro

Flood Risk Perceptions of Rideau and Roxboro Residents: AnExploratory Review

City of Calgary Riparian Zone Assessment



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Hydrologic Aspects of Elbow River

Watershed FloodingKim Beyak, Stephen dAbadie, Sarah Durham,

Mike Panek, Elise Savard, Ryan Willson



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Elbow River Watershed

Elbow Riverapproximately 120

km Watershed area is

1230 km2

Alluvial AquiferArea is 67 km2

25 year average

discharge 8 m

3

/s SignificantHistorical Floods in1923 and 1932


6/49Image from ENSC 502, 2002-2003

River-connected,

highly permeable, sandand gravel bottomlands

Elbow RiverAlluvial Aquifer


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Glacial drif t

Alluvial gravel

(aquifer)

Shale

Sandstone

river

Water table

Schematic cross section of Elbow River showing

alluvial aquifer

Meyboom, 1961


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The Big Question

How do hydrological aspects interact toinfluence flood magnitude and

frequency?

Bow River J une 2005: Center Street Bridge


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Study Purpose

1. What causes flooding? Precipitation in the watershed

Stream Discharge

Elbow River alluvial aquifer behaviour

2. During the 2005 flood event which one of thesethree factors was dominant? Are other flood

years similar?3. How accurate are recurrence intervals?


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Maximum discharge at each river gauging stationduring three major flood events.

10

100

1000

Bragg Creek Above Calgary Glenmore Dam

Log

Disc

harge

(cms

)

River Discharge does not increase significantly

moving downstream

Log

Discharge(m

3/s) 2005

1992

1990


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Floods can be influenced by more than just

precipitation

0

50

100

150

200

250

300

1981 1990 1995 2005

PeakDischarge(cms

0

10

20

30

40

50

60

70

PeakAnnualPrecipitation(m

Discharge (cms)" Precipitation (mm)

Comparing peak discharge volumes at Sarcee Bridge and precipitation amounts recordedat Elbow River Ranger Station for extreme years.


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1981 Elbow River Flood

interaction of climatic factors

Discharge Mean Temperature Total SnowfallTotal Rainfall

-300

-200

-100

0

100

200

300

400500

JanJanFebFebMarMarAprAprMayMa

yJunJunJul JulAugAugSepSe

pOctNovNovDecDe

c

Time (day)Quantity(cms,mmx

10,cmx

10,degrees

C)


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Does the alluvial aquifer return to pre-floodlevels between flood years?

Baseflow recession calculations depicting the amount of water stored within the aquifeduring the recession period following a peak discharge event.

-200

-100

0

100

200

300

400

1965-1

966

1966-1

967

1967-1

968

1968-1

969

1992-1

993

1993-1

994

1994-1

995

1995-1

996

1996-1

997

2002-2

003

2003-2

004

2004-2

005

Flow Recession Year

Es

timat

edAqu

iferS

torage

(M

illionso

fm

3)

* *


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Flood Recurrence Intervals

A Flood Recurrence Interval (RI) is theprobability of a flood of a given magnitudeoccurring in any given year

The term 1 in 100 yearor 1 in 5 yearflooddoes not refer to how often that flood occurs, butthe probability of that flood occurring

A 1 in 100 yearflood may occur more thanonce in 100 years


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Flood Probability Recurrence Intervals and Flows

1 in 20 Year Flood = 340 m3/s

1 in 100 Year Flood = 758 m3/s

(As calculated by Alberta Environment)

When flows exceed 170 m3/s flooding begins below thedam

Glenmore Reservoir was at 64 % of capacity

on J une 5, 2005


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RI for a flood of the magnitude experienced in J une 2005

Discharge Stations

Bragg Creek

Above Glenmore

Dam

Below Glenmore

Dam

(a) RI ( using allavailable years)

1 in 72 yrs(1934- 2005)

1 in 24 yrs(1979 - 2005)

1 in 49 yrs(1908 - 2005)

(b) RI (1979-2005at all stations) 1 in 28 yrs 1 in 24 yrs 1 in 28 yrs

Recurrence Intervals are

Sensitive to the Data Set


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Conclusions

1. Flooding is influenced most by climatic factors aboveBragg Creek

2. In 2005 the main factor influencing the flood magnitudewas precipitation upstream of Calgary In any given year a number of factors interact to determine the

magnitude of discharge in the Elbow River Precipitation is generally the flood trigger

3. Over-winter groundwater storage doesnt play a

significant role in spring floods

4. Recurrence interval estimation is highly sensitive to

length of data record


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Bow River EcologicalChanges Following

the 2005 Flood

Elizabeth Fulowski, Trevor Hirsche, J essica Martin,J enn Migdal, J oey Purcell, Erin Swerdfeger



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http://www.maroochy.qld.gov.au/maroochyriverrecovery/images/river_health.jpg

Healthy Unhealthy

Stable banks Bank erosion and sediment infill

Low sediment nutrientconcentrations

High sediment nutrientconcentrations

Low abundance of rock algaeand aquatic plants

High abundance of rock algaeand aquatic plants

Potential changes due to flooding

Healthy Unhealthy


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PurposeInvestigate the ecological changes after

the 2005 flood

StudyPre and post flood comparison using data

including last years ENSC 502 data


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Ogden

Heritage

Southland

Pine Creek

Ogden

Heritage

Southland

Pine Creek

Samples taken November5th and 10th, 2005

Methods followed AlbertaEnvironments (AENV)Water Quality SamplingManual 2002 or otherstandard methods

Study Area


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River Parameters

Rock algae (Periphyton)

Stream Insects (Macroinvertebrates) Aquatic Plants (Macrophytes)

River bed profiles River Sediment Nutrients

- Nitrogen (N) and Phosphorus (P)

Brown Trout spawning nests (redds)

- Elbow River

Summary of Results


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Summary of Results

Recovered quickly: Rock algaeTime for recovery unknown: Aquatic insects Variable response to flood Aquatic plants (dramatic decrease)

Little observed change: Water quality Trout redds

Other findings: Sediment nutrients lower in most samples


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Worm

(Oligochaeta)

http://www.inhs.uiuc.edu/~sjtaylor/cave/cave_ol

ig.jpg

Midge

(Chironomidae)

http://www.wwa-fs.bayern.de/datenufakten/Biologie/Bilder/chir

onomidae.jpg

Midge

(Simullidae)

http://www.arpa.vda.it/foto/figura_Simuliidae_26

18_s.jpg

Mayfly

(Ephemerillidae)

http://www.famu.org/mayfly/images/pluteus_nym.jpg

Caddisfly

(Tricoptera)

http://www.dec.state.ny.us/website/dow/stream/c

adb.jpg


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Results: Stream Insects

0 5 10 15 20 25

Ogden

Heritage

Southland

Pine Creek

Site

Number of Groups

2005

2004

At each site along the Bow River, insect diversity decreased from 2004 to2005.

A ti Pl t
http://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpg


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Aquatic Plants

Advantages

Traps sediment, thereby cleaning the water column

Habitat for stream insectsDisadvantages

Increases in sediment nutrients can lead to excessive

macrophyte growth Affects dissolved oxygen

http://members.fortunecity.com/macrophytes/aq13.jpg

http://members.fortunecity.com/macrophytes/aq10.jpg
http://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpghttp://members.fortunecity.com/macrophytes/aq13.jpg


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Results: Aquatic Plants

0

10

20

30

40

50

60

70

80

Ogden Heritage Southland Pine Creek

Site

Biom

ass

(g/m

2)

2005

2004

Macrophyte biomass observed at four sites in the Bow River with mean and

SE (standard error) for 2004 and 2005.


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0

50

100

150

200

250

300

350

400

450

1980 1983 1986 1989 1992 1995 1998 2001 2004

Number of Brown trout redds observed in the lower Elbow River since 1980(no survey 2003). Data courtesy of C. Bjornson, Golder Associates.

#

redds

Results: Brown Trout redds

No data availablethese years


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Results: River Bed Profiles

0

0.3

0.6

0.9

1.2

0 20 40 60 80 100

Distance from West Bank (m)

Dep

th

(m)

Before

After

0

1

2

3

0 15 30 45 60 75 90

Distance from West Bank (m)

Depth

(m)

Before

After

VE: ~7.5VE: ~30

Ogden Southland

Vertically Exaggerated (VE) stream profiles near the Ogden and Southland

sites showing the cross-section of the stream bed before and after the

flood.


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Conclusions

Major ecological changes were foundalong the Bow River

Some already recovered (rock algae),although other parameters may take a

while to recover Scouring is most likely responsible for

many of the changes

Further analysis would be required toestablish long term changes

Spatial Distribution of Flood


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Spatial Distribution of Flood

Damage in Rideau and RoxboroHow was the J une 2005 flood damage

distributed, and what influenced thatdistribution?

Distance from riverElevation above river

Were current bylaws appropriate for

minimizing damage?


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What did we study?

Tangible Damage

due to overland flowand undergroundseepage

Door-to-door survey

GIS to integrate and

evaluate data

Floodway

Floodfringe


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Initial Findings

Response Rate

96%

Total Amounts of Damage Within 6m Setback: > $1,150,000

Outside 6m Setback: > $1,157,000

P t f H S t i i D


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Percentage of Homes Sustaining Damage

74%26% Grandfathered

No Damage

GrandfatheredDamaged

70%30%

OutsideSetback No

Damage

OutsideSetback

Damaged

Overland Flow in the J une 2005 Flood


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JEvent

Overland flowaccounted foronly 17% of

total damage

Majority of

damage resultof groundwater

table comingup intobasement

Average Damage vs Distance from 6m Setback


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n=1

n=1

n=1

n=0

n=1

n=1

n=1

n=1

n=3

n=3

n=1

n=3

n=4

n=4

n=2

n=2n

=3

n=12

n=10

n=6

n=2

n=12

n=19

n=20

0

1

2

3

4

5

6

7

- 6 0 12 24 36 48 60 72 84 96 108 120 132 144 156 168 180 192 204 216 228 240 252 264

Distance from 6m Setback (m)

AverageDamage(tenofthousand

s$)

Average Damage vs. Distance from 6m Setback


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Proportional Damage to Homes

74% of homes inside setback damaged

63% of homes less than 6m outsidesetback damaged

Setback only moderately appropriate forminimizing damage

Damage vs. Ground Elevation above


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Ground elevation was as predictive of damageas distance from river

50% of flood damage occurred to homes withground elevations < 2.98m above the river (90%

to homes < 3.66mabove river)

Variability suggests other factors are relevant

gElbow River

Comparison of basement depth and


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p p

ground elevation with river stage

Study Conclusions


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Study Conclusions

Underground seepage (not overland flow)

responsible for most of flood damage

Ground elevation above river was as gooda predictor of this damage as distancefrom floodway

What does this tell us about the


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What does this tell us about the

setback?

A better approach:A better approach: Regulate basement depths with respect toRegulate basement depths with respect to

river (and water) table elevationriver (and water) table elevation

Consider zoning areas based on basementConsider zoning areas based on basementelevation above 1:100 year river (andelevation above 1:100 year river (and

groundwater level) as well as distance fromgroundwater level) as well as distance fromfloodwayfloodway


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Future City of CalgaryRiparian Zone Assessment

Presented by: Alison Beal


Elizabeth Fulowski, Trevor Hirsche, J essica Martin,J enn Migdal, J oey Purcell, Erin Swerdfeger

A t f Ri i H lth


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Assessment of Riparian Health

Previous work has been conducted at a

large scale by Cows and Fish along theSouth Saskatchewan River Basin

Extensive assessment within urban areaswill help to evaluate the riparian zonesusceptibility to erosion in future flood

events

Riparian Health in Calgary


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Riparian Health in Calgary

Proposed Assessment: Identify erosion susceptibility

Cost and benefit of re-naturalization EXAMPLE: Southland - outer meander exhibiting

substantial erosion after the flood

Photo courtesy of Don Binns,City of Calgary Parks

BEFORE AFTER

Riparian Zone Recommendations


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Riparian Zone Recommendations

Re-naturalizing bank may reduce impactof flood water on river banks

A healthy riparian zone including woodyvegetation is the most effective in limiting

erosion due to flooding

Acknowledgements


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g Don Binns City of Calgary Parks

Bert van Duin Westhoff Engineering Resources, Inc.

Mac Hickley Rivers Valley Council

Cathy Ryan - U of C, ENSC 502 Mentor Susan Ryan - RVC

Dr. Mary-Ellen Tyler U of C, EVDS

Photo courtesy of Susan Ryan

Acknowledgements


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Acknowledgements Don Binns City of Calgary Parks

Chris Bjornsen Golder Associates

Maarten Dankers ENSC graduate

Bert van Duin Westhoff Engineering Resources, Inc.

Mac Hickley Rivers Valley Council

Don Iredale U of C

Mike Iwanyshyn U of C

Doreen LeClair, Ray Walker, Al Sosiak - AENV

Farzin Malekani U of C

Brenda Mottle U of C

Dr. Cathy Ryan U of C

Gillian Savage and Travis J ohnson, U of C

Dr. Mary-Ellen Tyler U of C, EVDS

Acknowledgements


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Acknowledgements

David Nuell Cathy Ryan

Linda Henderson Mac Hickley Bill Morrison

Susan Ryan Chris Arko Bryce Haimila Larry Garner Terry Fedick Gordon Smith Dave Lieske

Acknowledgements


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Acknowledgements

Dr. Anil Gupta (AENV)

Dr. Masaki Hayashi (U of C) Mike Iwanyshyn (U of C)

Dr. Shawn Marshall (U of C)

Greg Rokosh (ENSC 502) Dr. Cathy Ryan (U of C)

Dr. Caterina Valeo (U of C)

Alberta Environment Environment Canada

Natural Resources Canada

ENSC502 05-06 Living With Our Rivers BRBC Combined

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