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Disentangling Impacts
of Climate & Land Use Changes
on the Quantity & Quality of River Flows
in Southern Ontario
by
Trevor...
Acknowledgements
 Agencies
 NSERC, OMAF & Environment Canada
 Personnel
 Barry Smith - Retired Program Manager, Water
...
River Flows Have Changed
0
20
40
60
80
100
120
Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Winter Spring Summer Fall
Flow
1916-1925
0
20
40
60
...
0
1
2
3
4
5
6
7
8
Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Winter Spring Summer Fall
Flow
2004-2013
0
1
2
3
4
5
6
7...
Monthly & Annual Precipitation
has remained unchanged.
0
200
400
600
800
1000
1200
1940 1950 1960 1970 1980 1990 2000 2010
AverageAnnualPrecipitation(mm)
Nith at New Hamburg Gra...
What’s Going On?!
Possible causes of changes in the river
flows include:
- Changes in Climate, and/or
- Changes in Land Us...
How Has Our Climate Changed?
Temperatures Have Risen
- mostly in the Winter
Annual Temperature Trends
Changes in Winter Mean Minimum Daily Temperature
Annual Temperature Trend Slopes
Rates of Increase in Temperatures
Celsius degrees per 100 years
Extreme Daily Minimum - 3.5 to 4.0
Mean Daily Minimum - 2....
So …
Temperatures have been increasing
somewhat steadily in Ontario,
- perhaps for up to and at least 150 years!
Winter te...
The Frequency of Frost – Free Days
has Increased Exponentially
Frost-Free Days
020040060080010001200
0
10
20
30
40
50
60
70
80
-25 -20 -15 -10 -5 0
NumberofFrost-FreeDaysperWinter
Winte...
Frost-Free Days
 As winter mean daily minimum temperatures
have been rising steadily, frost-free days have
been increasin...
There Has Been a Shift
in Winter Precipitation
from Snowfall to Rainfall
Changes in Winter Rainfall
Changes in Snowfall
Changes in Winter Precipitation
Total Precipitation
Total Precipitation
Total Precipitation
Snowfall
Snowfall
Snowfall
Rai...
Increased
Winter
Temperature
Increased
Number of
Frost-Free
Days
Shift from Snowfall to Rainfall
(i.e. fewer Snow Days & L...
What about Impacts on Snowpacks,
Winter Runoff & Infiltration
Likely Impacts I
Rising Winter
Temperatures
Increasing
Number of
Frost-Free
Days
Increased Winter Snowmelt
Likely Impacts II
Increased
Winter
Snowmelt
Increased
Winter
Rainfall
Increased Winter Surface
Runoff and/or Increased Win...
More Impacts I
Increased
Winter Tile Flow
Increased Winter
Groundwater
Recharge
Increased Winter
Infiltration
More Impacts II
Increased
Winter Surface
Runoff
Increased
Winter Tile Flow
& Recharge
Increased Winter Streamflow
And More
Increased
Winter
Snowmelt
Decreased
Snowfall
Decreased
End-of-Winter
Snowpack
Decreased
Snowmelt
Floods
Decreased...
0
20
40
60
80
100
120
140
160
Dec
Dec
Dec
Jan
Jan
Jan
Feb
Feb
Mar
Mar
Mar
Apr
Apr
May
May
May
Jun
Jun
Jun
Jul
Jul
Aug
Aug
...
Rural Streamflows
So …
for Ontario Rural Watersheds,
changes in winter climate have:
- increased winter streamflows
and
- ...
Water Quality Impacts
What about Water Quality Impacts
Are we now seeing more frequent and greater:
- Field & Streambank E...
What about Impacts of
Urban Development?
0
1
2
3
4
5
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7
8
Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Winter Spring Summer Fall
Flow 2004-2013
0
1
2
3
4
5
6
7...
0
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10
15
20
25
30
35
Dec
Dec
Dec
Jan
Jan
Jan
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Feb
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Mar
Mar
Apr
Apr
May
May
May
Jun
Jun
Jun
Jul
Jul
Jul
Aug
Aug
...
0.0
0.2
0.4
0.6
0.8
1.0
April May June July August September October
Significant Urbanization (50%)
0.0
0.2
0.4
0.6
0.8
1....
Streamflow Volumes
So …
in Ontario urban watersheds:
- urban development has augmented the winter
and spring climate chang...
Impacts of Urbanization on
River Water Quality
Are we seeing more frequent flushes and greater
volumes of:
- streambank er...
Conclusions
River flows have changed in Southern Ontario:
- in winter and spring, primarily due to climate
change; and
- d...
Questions
Water Management Questions
What do we do about the changes in river flows
- in urbanized and urbanizing watershe...
Questions
???
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80
100
120
Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Winter Spring Summer Fall
Flow
1916-1925
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40
60
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Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
Winter Spring Summer Fall
Flow
2004-2013
0
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2
3
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7...
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...
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Disentangling Impacts of Climate & Land Use Change on Quantity & Quality of River Flows in Southern Ontario Trevor Dickinson Ramesh Rudra University of Guelph

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Climate change has lowered spring flood risks in Ontario rural watersheds due to higher temperatures, lower snowpack and lower spring runoff volumes. There have been no changes in precipitation affecting runoff volumes, and observed increases in summer runoff are due to urbanization, not climate change effects. Dr. Dickinson and Dr Rudra rightly describe the need for 'disentangling', given the prevalent approach of ignoring hydrologic changes in watersheds and incorrectly linking flood events on climate change and extreme rainfall and precipitation changes that have not been observed in local and regional data.

These findings on annual and seasonal patterns complement work by Environment and Climate Change Canada on short duration rainfall that shows no detectable trend in rainfall intensities in the Engineering Climate Datasets contrary to insurance industry statements:

https://www.slideshare.net/RobertMuir3/storm-intensity-not-increasing-factual-review-of-engineering-datasets

Published in: Engineering
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Disentangling Impacts of Climate & Land Use Change on Quantity & Quality of River Flows in Southern Ontario Trevor Dickinson Ramesh Rudra University of Guelph

  1. 1. Disentangling Impacts of Climate & Land Use Changes on the Quantity & Quality of River Flows in Southern Ontario by Trevor Dickinson & Ramesh Rudra, Water Resources Engineering University of Guelph
  2. 2. Acknowledgements  Agencies  NSERC, OMAF & Environment Canada  Personnel  Barry Smith - Retired Program Manager, Water Survey of Canada  Golmar Golmohammadi – Post Doctoral Research Fellow  Arezoo Amili – Former Graduate Student  Akul Bhatt – Undergraduate Student Assistant
  3. 3. River Flows Have Changed
  4. 4. 0 20 40 60 80 100 120 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 1916-1925 0 20 40 60 80 100 120 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 2004-2013 Average Monthly Flow Hydrographs For Rural Watersheds like the Moira River at Foxboro: winter flows have increased, spring flows have decreased, & summer flows have remained unchanged.
  5. 5. 0 1 2 3 4 5 6 7 8 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 2004-2013 0 1 2 3 4 5 6 7 8 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 1916-19251963-1972 Average Monthly Flow Hydrographs For a highly Urbanized Watershed like the Don River at Todmorden: winter flows have increased, spring flows have decreased, & summer flows have greatly increased.
  6. 6. Monthly & Annual Precipitation has remained unchanged.
  7. 7. 0 200 400 600 800 1000 1200 1940 1950 1960 1970 1980 1990 2000 2010 AverageAnnualPrecipitation(mm) Nith at New Hamburg Grand at Brantford Cedar Creek at Woodstock Moira near Foxboro Linear (Nith at New Hamburg) Linear (Grand at Brantford) Linear (Cedar Creek at Woodstock) Linear (Cedar Creek at Woodstock) Linear (Moira near Foxboro)
  8. 8. What’s Going On?! Possible causes of changes in the river flows include: - Changes in Climate, and/or - Changes in Land Use i.e. Urban Development
  9. 9. How Has Our Climate Changed?
  10. 10. Temperatures Have Risen - mostly in the Winter
  11. 11. Annual Temperature Trends
  12. 12. Changes in Winter Mean Minimum Daily Temperature
  13. 13. Annual Temperature Trend Slopes
  14. 14. Rates of Increase in Temperatures Celsius degrees per 100 years Extreme Daily Minimum - 3.5 to 4.0 Mean Daily Minimum - 2.0 Mean Daily - 1.5 Mean Daily Maximum - 0.5 Extreme Daily Maximum - 0 to – 0.5
  15. 15. So … Temperatures have been increasing somewhat steadily in Ontario, - perhaps for up to and at least 150 years! Winter temperatures have been rising at the greatest rate, suggesting that winter hydrology may have been impacted more than summer hydrology. Temperature Trends
  16. 16. The Frequency of Frost – Free Days has Increased Exponentially
  17. 17. Frost-Free Days 020040060080010001200 0 10 20 30 40 50 60 70 80 -25 -20 -15 -10 -5 0 NumberofFrost-FreeDaysperWinter Winter Mean Daily Minimum Temperature (°C) Number of Frost-Free Days versus Mean Daily Minimum Temperature per Winter for 7 Weather Stations WMDMT y = 115.67exp(0.1729x) R² = 0.9496 + 15 days in 60 years + 5 days in 60 years + 1 day in 60 years
  18. 18. Frost-Free Days  As winter mean daily minimum temperatures have been rising steadily, frost-free days have been increasing exponentially.  Might snowmelt, which is related to degree-days, also have been increasing exponentially?
  19. 19. There Has Been a Shift in Winter Precipitation from Snowfall to Rainfall
  20. 20. Changes in Winter Rainfall
  21. 21. Changes in Snowfall
  22. 22. Changes in Winter Precipitation Total Precipitation Total Precipitation Total Precipitation Snowfall Snowfall Snowfall Rainfall Rainfall Rainfall
  23. 23. Increased Winter Temperature Increased Number of Frost-Free Days Shift from Snowfall to Rainfall (i.e. fewer Snow Days & Less Snowfall, & more Rainy Days & Winter Rainfall)
  24. 24. What about Impacts on Snowpacks, Winter Runoff & Infiltration
  25. 25. Likely Impacts I Rising Winter Temperatures Increasing Number of Frost-Free Days Increased Winter Snowmelt
  26. 26. Likely Impacts II Increased Winter Snowmelt Increased Winter Rainfall Increased Winter Surface Runoff and/or Increased Winter Infiltration
  27. 27. More Impacts I Increased Winter Tile Flow Increased Winter Groundwater Recharge Increased Winter Infiltration
  28. 28. More Impacts II Increased Winter Surface Runoff Increased Winter Tile Flow & Recharge Increased Winter Streamflow
  29. 29. And More Increased Winter Snowmelt Decreased Snowfall Decreased End-of-Winter Snowpack Decreased Snowmelt Floods Decreased End-of-Winter Snowpack
  30. 30. 0 20 40 60 80 100 120 140 160 Dec Dec Dec Jan Jan Jan Feb Feb Mar Mar Mar Apr Apr May May May Jun Jun Jun Jul Jul Aug Aug Aug Sep Sep Oct Oct Oct Nov Nov Winter Spring Summer Fall Flow(cms) 1916-1925 0 20 40 60 80 100 120 140 160 Dec Dec Dec Jan Jan Jan Feb Feb Mar Mar Mar Apr Apr May May May Jun Jun Jun Jul Jul Aug Aug Aug Sep Sep Oct Oct Oct Nov Nov Winter Spring Summer Fall Flow(cms) 2004-2013 Average Daily Flow Hydrographs Moira River at Foxboro
  31. 31. Rural Streamflows So … for Ontario Rural Watersheds, changes in winter climate have: - increased winter streamflows and - decreased spring runoff/freshettes.
  32. 32. Water Quality Impacts What about Water Quality Impacts Are we now seeing more frequent and greater: - Field & Streambank Erosion, - Stream Sediment Loads, and - Nutrient Loads. in rural watersheds during the winter? Have these loads become smaller and less frequent during spring snowmelt events?
  33. 33. What about Impacts of Urban Development?
  34. 34. 0 1 2 3 4 5 6 7 8 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 2004-2013 0 1 2 3 4 5 6 7 8 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 1916-19251963-1972 Average Monthly Flow Hydrographs For a highly urbanized basin like the Don River, winter flows have increased & spring flows have decreased likely as a result of both Climate Change & Urban Development. In addition, the summer flows have increased significantly in volume …
  35. 35. 0 5 10 15 20 25 30 35 Dec Dec Dec Jan Jan Jan Feb Feb Feb Mar Mar Mar Apr Apr May May May Jun Jun Jun Jul Jul Jul Aug Aug Aug Sep Sep Sep Oct Oct Nov Nov Nov Spring Summer Fall Flow(cms) 1915-19251963-1972 0 5 10 15 20 25 30 35 Dec Dec Dec Jan Jan Jan Feb Feb Feb Mar Mar Mar Apr Apr May May May Jun Jun Jun Jul Jul Jul Aug Aug Aug Sep Sep Sep Oct Oct Nov Nov Nov Spring Summer Fall Flow(cms) 2004-2013 Average Daily Flow Hydrographs … and in frequency on the Don River at Todmorden. What’s going on?!
  36. 36. 0.0 0.2 0.4 0.6 0.8 1.0 April May June July August September October Significant Urbanization (50%) 0.0 0.2 0.4 0.6 0.8 1.0 April May June July August September October Initial Urbanization 0.0 0.2 0.4 0.6 0.8 1.0 April May June July August September October Before Urbanization Runoff Coefficients  Meaneventrunoffcoefficient
  37. 37. Streamflow Volumes So … in Ontario urban watersheds: - urban development has augmented the winter and spring climate change impacts; and - summer flow volumes have increased dramatically, in volume and frequency, these impacts being completely due to urban development.
  38. 38. Impacts of Urbanization on River Water Quality Are we seeing more frequent flushes and greater volumes of: - streambank erosion - suspended sediment loads - Chlorides and other pollutants - sewage bypasses ???
  39. 39. Conclusions River flows have changed in Southern Ontario: - in winter and spring, primarily due to climate change; and - during the summer, primarily due to urban development.
  40. 40. Questions Water Management Questions What do we do about the changes in river flows - in urbanized and urbanizing watersheds? How have these changes modified water quality, and what do we do in that regard?
  41. 41. Questions ???
  42. 42. 0 20 40 60 80 100 120 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 1916-1925 0 20 40 60 80 100 120 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 2004-2013 Monthly Average Flow Hydrograph Moira River at Foxboro
  43. 43. 0 1 2 3 4 5 6 7 8 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 2004-2013 0 1 2 3 4 5 6 7 8 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Winter Spring Summer Fall Flow 1916-19251963-1972 Monthly Average Flow Hydrograph Don River at Todmorden
  44. 44. 0 20 40 60 80 100 120 140 160 Dec Dec Dec Jan Jan Jan Feb Feb Mar Mar Mar Apr Apr May May May Jun Jun Jun Jul Jul Aug Aug Aug Sep Sep Oct Oct Oct Nov Nov Winter Spring Summer Fall Flow(cms) 1916-1925 0 20 40 60 80 100 120 140 160 Dec Dec Dec Jan Jan Jan Feb Feb Mar Mar Mar Apr Apr May May May Jun Jun Jun Jul Jul Aug Aug Aug Sep Sep Oct Oct Oct Nov Nov Winter Spring Summer Fall Flow(cms) 2004-2013 Daily Average Flow Hydrograph Moira River at Foxboro

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