Characterizing change in baseflow interactions with urbanization through event-based hydrograph separation and analysis Peter John Thompson Earthfx Inc. Dr. William K. Annable Department of Civil and Environmental Engineering University of Waterloo IAH 2012 Congress September 21, 2012
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Characterizing Change in Baseflow Interactions with Urbanization Through Event-Based Hydrograph Separation and Analysis
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Characterizing change in baseflow interactions with urbanization through
event-based hydrograph separation and analysis
Peter John Thompson Earthfx Inc.
Dr. William K. Annable
Department of Civil and Environmental Engineering University of Waterloo
IAH 2012 Congress
September 21, 2012
Effects of Urbanization
• Increase in impervious area
• Shorter events
• Larger peak discharge
• Infiltration
• Changes to frequency
• Channelization
• Change in vegetative cover
• Habitat degradation
• Erosion
• Poor water quality
• Failure of engineered structures
2
AAfafdas
Hydrograph Change with Urbanization
Time (T) Time (T)
Rain
fall
(L
)
Dis
ch
arg
e (
L/T
3)
After
Urbanization
Original
Lag time after
urbanization
Hydrograph
of streamflow
Lag time
Center of mass
of runoff
and of rainfall
Dis
ch
arg
e (
L/T
3)
Rainfall
•Changes to event hydrograph with urbanization...?
02HC005 – Don River at York Mills Effective Catchment Area – 95.5 km2
Urban Stream Flow Data
• Need high resolution, high frequency data
• Joint project with Water Survey of Canada
• Extracted archived stream flow data to create a complete hydrometric record from 1969 to present
12
Daily vs. Instantaneous Data
Daily vs. Instantaneous Data
15
Event Separation Algorithm
• Suite of hydrograph visualization and analysis tools written in VB .net
16
Event Separation Algorithm
Typical Event Hydrograph
Qpeak
Qend
Qstart Qreg
Time
Dis
cha
rge
Qpivot
tstart tpeak tend treg
Trise Tevent Trec
Vevent
Q75
Q50
T75
T50 Rising Limb
Falling Limb
Recession Limb
17
Mann-Kendall Test
• Non-parametric test for monotonic trends
• Independent events assumed to be uncorrelated
• Trends tested to a 95% significance level ( p ≤ 0.025 )
0 if1
0 if0
0 if1
sgn
1
1 1
sgnn
k
n
kj
kj xxS
18
Peak Event Discharge
MK Trend: Increasing
Peak Event Discharge
Station Name Trend
Duffins Creek above Pickering
East Humber River near Pine Grove
East Oakville Creek near Omagh
Laurel Creek at Waterloo ↑
Redhill Creek at Hamilton
Black Creek near Weston ↑
Etobicoke Creek at Brampton ↑
Etobicoke Creek below QEW ↑
Mimico Creek at Islington ↑
Don River at York Mills ↑
Little Don River at Don Mills ↑
Don River at Todmorden ↑
Rouge River near Markham ↑
Highland Creek near West Hill ↑
Harmony Creek at Oshawa ↑
Number of Events per Year
Station Name Trend
Duffins Creek above Pickering
East Humber River near Pine Grove
East Oakville Creek near Omagh
Laurel Creek at Waterloo
Redhill Creek at Hamilton
Black Creek near Weston
Etobicoke Creek at Brampton ↑
Etobicoke Creek below QEW
Mimico Creek at Islington
Don River at York Mills ↑
Little Don River at Don Mills ↑
Don River at Todmorden
Rouge River near Markham ↑
Highland Creek near West Hill ↑
Harmony Creek at Oshawa ↑
Event Volume
Station Name Trend
Duffins Creek above Pickering
East Humber River near Pine Grove
East Oakville Creek near Omagh
Laurel Creek at Waterloo ↑
Redhill Creek at Hamilton ↑
Black Creek near Weston
Etobicoke Creek at Brampton ↑
Etobicoke Creek below QEW ↑
Mimico Creek at Islington ↑
Don River at York Mills ↓
Little Don River at Don Mills ↑
Don River at Todmorden ↑
Rouge River near Markham ↑
Highland Creek near West Hill
Harmony Creek at Oshawa
Total Event Duration
Station Name Trend
Duffins Creek above Pickering
East Humber River near Pine Grove
East Oakville Creek near Omagh ↓
Laurel Creek at Waterloo
Redhill Creek at Hamilton
Black Creek near Weston ↓
Etobicoke Creek at Brampton ↓
Etobicoke Creek below QEW ↑
Mimico Creek at Islington ↑
Don River at York Mills ↓
Little Don River at Don Mills ↑
Don River at Todmorden ↓
Rouge River near Markham ↑
Highland Creek near West Hill ↓
Harmony Creek at Oshawa ↓
Hydrograph Separation
Qpeak
Qstart
Qreg
Time
Dis
cha
rge
Qpivot
tstarttpeak
treg
Quick (Direct)Flow
Inter Flow
Base Flow
Constant Slope Method Inflection Point Solver
• Find inflection point on falling limb via non-linear curve fitting
• Separate linear storage volumes
Hydrograph Separation
25
Event Quick Flow (Direct Runoff) Volume
Station Name Trend
Duffins Creek above Pickering
East Humber River near Pine Grove
East Oakville Creek near Omagh
Oakville Creek at Milton ↓
Credit River near Orangeville
Black Creek near Weston
Etobicoke Creek at Brampton ↑
Etobicoke Creek below QEW ↑
Mimico Creek at Islington ↑
Don River at York Mills
Little Don River at Don Mills ↑
Don River at Todmorden
Rouge River near Markham ↑
Highland Creek near West Hill ↑
Harmony Creek at Oshawa
MK Trend: Increasing
Event Interflow Volume
Station Name Trend
Duffins Creek above Pickering ↑
East Humber River near Pine Grove
East Oakville Creek near Omagh
Oakville Creek at Milton
Credit River near Orangeville
Black Creek near Weston ↑
Etobicoke Creek at Brampton
Etobicoke Creek below QEW ↑
Mimico Creek at Islington ↑
Don River at York Mills
Little Don River at Don Mills ↑
Don River at Todmorden ↑
Rouge River near Markham ↑
Highland Creek near West Hill ↑
Harmony Creek at Oshawa ↑
MK Trend: Increasing
Zombie Science?
28
“Results from these comparisons show that depending on the method used, automated baseflow separation underestimates the simulated baseflow by as much as 28%, or overestimates it by up to 74%, during rainfall events.” (Partington et al., 2012)
Conclusions
• While direct runoff increases in urbanizing catchments, event contribution to shallow system may increase or decrease
• Hydrograph separation methods have relevance in modern hydrology, more work required
• Must work towards integrated SW/GW definitions
• Canada has an large database of high resolution, instantaneous hydrometric data spanning from 1969 onwards
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Acknowledgements
Dr. Herman Goertz Jeanette Fooks
Paula Hunter Carrie-Lynn Green
Eco-Hydraulics Co-op
Tyler Gale
Victoria Lounder
Ben Plumb
Christina Bright
Water Survey Division, Environment Canada
Tom Arsenault
Aerial Photography Analysis
Robert Leonard
Nikita Tirskikh
Chris McKie
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Questions or Comments?
WSC
Station ID Station Name
Area
(km2)
Percent
Urban
(1969)
Percent
Urban
(≈2010)
Percent
Change
02HC019 Duffins Creek above Pickering 93.5 > 5% --
02HC009 East Humber River near Pine Grove 197 > 10% --
02HB004 East Oakville Creek near Omagh 199 > 10% --
02GA024 Laurel Creek at Waterloo 57.5 15 38 23
02HA014 Red Hill Creek at Hamilton 56.3 27 60 33
02HC027 Black Creek near Weston 58 55 78 22
02HC017 Etobicoke Creek at Brampton 63.2 1 18 17
02HC030 Etobicoke Creek below QEW 204 20 55 34
02HC033 Mimico Creek at Islington 70.6 43 82 39
02HC005 Don River at York Mills 88.1 30 69 39
02HC029 Little Don River at Don Mills 130 30 68 38
02HC024 Don River at Todmorden 316 43 73 30
02HC022 Rouge River near Markham 186 7 40 33
02HC013 Highland Creek near West Hill 88.1 47 86 39