1 Restoring Water Levels on Lakes Michigan-Huron: Impact Analysis IUGLS Study Board Meeting Windsor, ON Nov 30, 2010 Bryan Tolson 1 Masoud Asadzadeh Saman Razavi 1. Assistant Professor Department of Civil and Environmental Engineering

2 Introduction Purpose is to assess the impacts of “restoring” Lake MH levels by 10 cm to 50 cm x-cm restoration here is defined as a permanent structural change to the St. Clair River that raises the long term average of Lake MH by x-cm The actual structural change is not specified and thus the actual hydraulic impacts are not assessed here Instead, we assume that reducing the conveyance of the St. Clair River as simulated in the co-ordinated routing model (CGLRRM) is roughly representative of system-wide restoration impacts of some actual structural change to reduce St. Clair River conveyance

3 Q SC = K SC ((MH+SC)/2-ym SC ) a SC (MH-SC) b SC -IW ym SC : Mean Channel Bottom Elevation of St. Clair River With the default value of m With the default value of m Base case: ym SC = m Quantifying Restoration Equation below describes the conveyance of the St. Clair River in CGLRRMEquation below describes the conveyance of the St. Clair River in CGLRRM We simulate the system with the Equation coefficients set to describe the current conveyance regime of the riverWe simulate the system with the Equation coefficients set to describe the current conveyance regime of the river to simulate system under restoration, we manipulate a coefficient in Equation to reduce conveyance of the riverto simulate system under restoration, we manipulate a coefficient in Equation to reduce conveyance of the river primarily, we consider ym SCprimarily, we consider ym SC

4 Q SC = K SC ((MH+SC)/2-ym SC ) a SC (MH-SC) b SC -IW Increase ym SC from so that the long-term average MH lake level increases by 10, 25, 40, and 50 cm Restoration average is calculated over the final 55 years of the simulation ( ‘equilibrium’ is reached … MH stops filling) Quantifying Restoration Restoration impacts are assessed with CGLRRM+1958DD down to Montreal (Jetty1) simulating 109 years of lake levels based on (historical) residual NBS In a sensitivity analysis, we will repeat with K SC (function of mean channel cross-section area and roughnessrather than ym SC In a sensitivity analysis, we will repeat with K SC (function of mean channel cross-section area and roughness) rather than ym SC

Outline of Restoration Scenarios factors we will vary to define scenarios include: – 10 cm, 25 cm, 40 cm, 50 cm restoration targets – static versus dynamic behaviour of Lake Superior – one-time (instantaneous) versus staged restoration – vary initial lake levels/NBS inflows to estimate worst-case downstream restoration impacts (Lake Erie  1930s, 1960s) – restoration via the ym SC versus the K SC coefficient # levels [4] [2] [3] [2] we do not evaluate impacts of all 4x2x2x3x2 = 96 combinations of factor levels we only evaluate impacts for some of these

Outline of Restoration Scenarios Unless otherwise noted, you can assume the following factor levels for all restoration results: – 10 cm, 25 cm, 40 cm or 50 cm restoration target (will be specified in all results) – static behaviour of Lake Superior – one-time (instantaneous) restoration at start of year 1 in simulation (year 1900 initial lake levels) – restoration via the ym SC (bottom level) coefficient

7 Restoration Scenarios Static Plan 77A for Superior releases: – Run 77A for the base case where ym SC = m – Take the outflow of lake Superior – Study the effect of adjusting ym SC on Midlakes by simulating only Midlakes with static inflow to MH (outflow of Lake Superior constant at the base case) Dynamic 77A: – Study the effect of adjusting ym SC on Superior and Midlakes (Lake Superior with plan 77A as well as Midlakes) – here Lake Superior levels (through Plan 77A) are allowed to respond to restoration Static 77A deemed most representative of trying to restore Lake MH levels without changing/degrading Lake Superior levels

8 RESULTS for STATIC 77A Upstream Effects of Restoration Downstream Effects of Restoration

9 Lakes Michigan Huron Response to 1-TIME Restoration

10 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case max-10cm res

11 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case max-10cm res (%) violating base case max-25cm res (%) violating base case max-40cm res (%) violating base case max-50cm res cm

MetricRest. lev.JanFebMarAprMayJunJulAugSepOctNovDec MH violating long-term base case max(%) Max Violation (cm) Time MH Restoration – STATIC 77A Long-Term Upstream Effects more extreme flooding more frequently on Lake MH due to restoration

13 RESULTS for STATIC 77A Upstream Effects of Restoration Downstream Effects of Restoration

14 St. Clair River Response to 1-TIME Restoration

15 Lake St. Clair Response to 1-TIME Restoration

16 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case min-10cm res (%) violating base case max-10cm res

17 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case min-10cm res (%) violating base case max-10cm res (%) violating base case min-50cm res (%) violating base case max-50cm res

Long-term Impacts Downstream of Lake St. Clair Results again for Lake St. Clair All further downstream long term impacts look very much the same (0-2% increase in frequency for 50 cm restoration) focus attention on short-term impacts downstream JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case min-10cm res (%) violating base case max-10cm res (%) violating base case min-50cm res (%) violating base case max-50cm res

19 Detroit River Response to 1-TIME Restoration

20 Lake Erie Response to 1-TIME Restoration

21 Niagara River + Welland Canal Response to 1-TIME Restoration

22 Lake Ontario (Plan 58DD*) Response to 1-TIME Restoration

23 Lake Ontario Outflow Response to 1- TIME Restoration

24 Montreal Jetty1 Level Response to 1-TIME Restoration

25 Monthly Metric Res. Lv.SCERONJETSCRDRNiRONout cm cms Max decrease to base case Max decrease to base case min Max increase to base case Max increase to base case max Time Restoration – STATIC 77A Short-Term Downstream Effects How are most extreme base case levels exacerbated Short-term impacts limited to ~10 yrs, max. impacts within year 1

Mitigating Short-term Downstream Impacts of Restoration

27 Staged vs 1-Time Restoration Short-term downstream impacts of restoration can be minimized by spreading them out (staging) over time essentially this means filling Lake MH more slowly We evaluate a staged 25 cm restoration case and compare to 1-time restoration (same principle applies to any restoration scenario) Staged restoration scenario evaluated: – 5 stages of restoration – each restoring 5 cm to Lake MH – each spaced in time by 5 years – thus, 20 yrs between start and end of physical restoration changes

28 Lakes Michigan Huron Response to 1- Time vs. STAGED Restoration Staged restoration accomplishes same thing as 1-time restoration in the long term

29 St. Clair River Response to 1Time vs. STAGED Restoration

30 Lake St. Clair Response to 1Time vs. STAGED Restoration

31 Detroit River Response to 1Time vs. STAGED Restoration

32 Lake Erie Response to STAGED Restoration

33 Niagara River + Welland Canal Response to STAGED Restoration

34 Lake Ontario Response to STAGED Restoration

35 Lake Ontario Outflow Response to STAGED Restoration

36 Jetty1 Response to STAGED Restoration

Staged Restoration Summary Findings 25 cm staged restoration can almost completely mitigate the negative downstream impacts of a one-time restoration similar concept applies to any other selected level of restoration exact mitigation extent is of course dependent on being able to stage whatever structural channel changes are selected minimal downstream impact restoration (staging) takes longer (25 yrs instead of 10 yrs in this example) 37

38 Sensitivity of Short-term Restoration Impacts to Initial Lake Levels/NBS variability Purpose here is assess worst case short-term downstream impacts due to a poorly-timed project [Worst case impacts upstream are in the long-term and so timing a project to start during a high water period will not be worse - all we would show is that it would be better to start project during high water period] How are impacts exacerbated if physical restoration changes are completed just before period of very low Lake Erie levels? Based on observed Lake Erie levels, there are two points in historical record to consider …

39 Simulated Lake Erie Level under Base Case “1930s” start “1960s” start

40 Starting the 10cm Restoration in Dry Period of the 30’s

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47 Starting the 10cm Restoration in Dry Period in 60’s

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Restoration start year Maximum monthly lake level decrease compared to base case (no-restoration) Annual average decrease to the base case in the first year after restoration cm Lake Erie Response to Various Starting Years of 1-TIME 10cm Restoration

56 Starting the 25cm Restoration in Dry Period in 30’s

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59 Starting the 25cm Restoration in Dry Period in 60’s

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Restoration start year Maximum monthly lake level decrease compared to base case (no-restoration) Annual average decrease to the base case in the first year after restoration cm Lake Erie Response to Various Starting Years of 1-TIME 25 cm Restoration

Summary of Sensitivity to Restoration Project Timing A worst-case poorly-timed 1-time 10 cm restoration might drop ‘record’ low Lake Erie levels by an additional 7 cm for ~1 year A worst-case poorly-timed 1-time 25 cm restoration might drop ‘record’ low Lake Erie levels by an additional 12 cm for ~1 year The above results require terrible timing and would be difficult to imagine in practice … just a few years difference can reduce impacts Nonetheless, staged restoration can guard against such worst-case impacts

64 RESULTS for Dynamic 77A Allow Lake Superior to respond to restoration Upstream Effects of Restoration Downstream Effects of Restoration

65 Lake Superior Response to 1-TIME Restoration

66 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case max-10cm res (%) violating base case max-25cm res (%) violating base case max-40cm res (%) violating base case max-50cm res cm

67 Monthly metric Res. Lv.SUPMHSM cm cms Max increase to base case Max increase to base case max Max decrease to base case Max decrease to base case min Time MH Restoration DYNAMIC 77A Upstream Effects How are most extreme base case levels exacerbated

68 RESULTS for Dynamic 77A Upstream Effects of Restoration Downstream Effects of Restoration

69 St. Clair River Response to 1-TIME Restoration

70 Lake St. Clair Response to 1-TIME Restoration

71 Detroit River Response to 1-TIME Restoration

72 Lake Erie Response to 1-TIME Restoration

73 Niagara River + Welland Canal Response to 1-TIME Restoration

74 Lake Ontario Response to 1-TIME Restoration

75 Lake Ontario Outflow Response to 1-TIME Restoration

76 Jetty1 Response to 1-TIME Restoration

77 Monthly metric Res. Lv.SCERONJETSCRDRNiR cm cms Max decrease to base case Max decrease to base case min Max increase to base case Max increase to base case max Time MH Restoration Short-Term Downstream Effects STATIC vs. DYNAMIC 77A How are most extreme base case levels exacerbated

Summary of Dynamic vs Static Plan 77a Dynamic Plan 77a implies Lake MH restoration will permanently increase Lake Superior levels The ‘filling’ of both Superior and Lake MH shows very minimal downstream impacts in comparison with Static 77a We have assumed Static 77a represents most likely approach to restoration However, if Dynamic 77a (restoring Superior) was desired restoration goal then Dynamic 77a results should be repeated with more realisitic Dynamic 77a plan parameters … no plans to do this

79 Sensitivity of Restoration Impacts to Coefficient Adjusted in St. Clair River Eqn

80 Q SC = K SC ((MH+SC)/2-ym SC ) a SC (MH-SC) b SC -IW K SC : St. Clair River outflow equation coefficient (default ) A function of mean channel cross-section area and roughness mimic reducing channel width instead of increasing bottom elevation mimic reducing channel width instead of increasing bottom elevation Evaluate sensitivity with Static 77A, 10cm and 25 cm restoration Sensitivity of Restoration Impacts to Coefficient Adjusted in St. Clair River Eqn

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83 Rest. level Monthly deviation between results of adjusting two different parameters MHSCERONJETSCRDRNiRONout cmcms 10 max. positive deviation max. negative deviation Average deviation max. positive deviation max. negative deviation Average deviation Sensitivity of Restoration Impacts to Coefficient Adjusted in St. Clair River Eqn except for Jetty1 at Montreal, pretty limited downstream differences in findings except for Jetty1 at Montreal, pretty limited downstream differences in findings at Jetty1 these are extreme deviations at Jetty1 these are extreme deviations Results/Impacts should generally be representative of a variety of physical changes to St. Clair river Results/Impacts should generally be representative of a variety of physical changes to St. Clair river

84 Conclusions

85 Summary of Upstream Impacts of One-time Restoration (Static 77a) Full upstream impacts only realized after initial period of “filling” for Lake MH, which is roughly yrs Restoration will result in more extreme flooding more frequently on Lake MH depending on restoration level: – for 10 cm restoration, base case extreme monthly levels will be exceeded 1-3% of the time – for 50 cm restoration, base case extreme monthly levels will be exceeded upwards of 15% of the time Increased flooding level corresponds to restoration amount (cm)

86 Summary of Downstream Impacts of One-time Restoration (Static 77a) Downstream impacts are short-term due to holding water back to “fill” Lake MH, roughly yrs Short-term downstream impacts vary based on restoration level and impact location but they can be significant – in particular for larger restorations Short-term downstream impacts can be greatly reduced with staged restoration and advanced planning on Lake Ontario – for example 25 cm staged restoration can almost completely mitigate the negative downstream impacts of a one-time restoration

Conclusions on Project Timing A worst-case poorly-timed 1-time 10 cm restoration might drop ‘record’ low Lake Erie levels by an additional 7 cm for ~1 year A worst-case poorly-timed 1-time 25 cm restoration might drop ‘record’ low Lake Erie levels by an additional 12 cm for ~1 year The above results require terrible timing and would be difficult to imagine in practice … just a few years difference can reduce impacts Nonetheless, staged restoration can guard against such worst-case impacts

88 Limitations of the Analysis The hydraulic behaviour of the eventual physical structure/channel modifications to accomplish restoration is not simulated here This analysis assumes that an increase to the channel bottom elevation and the corresponding simulation with CGLRRM roughly approximates the overall system response to a structural change in the St Clair River Before any physical restoration work is initiated, more accurate impacts for the actual physical structure/channel modifications should be evaluated by hydraulic modelling

Finalize this in report for the board ASAP THANKS … questions?

APPENDICES

91 Summary of Bottom Level Coefficient of St. Clair (ym SC ) for Static 77A Restoration on MH (cm)Bottom level of SC (m)Bottom level change in SC to the base case (cm) 0 (base case) staged

Monthly Metric 25 cm restoration Scenarios SCERONJetSCRDRNiR cmcms Max decrease to base case 1-Time Staged Max decrease to base case min 1-Time Staged Max increase to base case 1-Time Staged Max increase to base case max 1-Time Staged EDIT*** 1-Time vs. Staged 25cm MH Restoration – STATIC 77A Short-Term Downstream Effects

Full Dynamic 77A Results

94 Lake Superior Response to 1-TIME Restoration

95 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case max-10cm res (%) violating base case max-25cm res (%) violating base case max-40cm res (%) violating base case max-50cm res cm

96 St. Marys River Response to 1-TIME Restoration

97 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case max-10cm res (%) violating base case max-25cm res (%) violating base case max-40cm res (%) violating base case max-50cm res

98 Lakes Michigan Huron Response to 1-TIME Restoration

99 JanFebMarAprMayJunJulAugSepOctNovDec (%) violating base case max-10cm res (%) violating base case max-25cm res (%) violating base case max-40cm res (%) violating base case max-50cm res cm

100 Monthly metric Res. Lv.SUPMHSM cm cms Max increase to base case Max increase to base case max Max decrease to base case Max decrease to base case min Time MH Restoration DYNAMIC 77A Upstream Effects

101 St. Clair River Response to 1-TIME Restoration

102 Lake St. Clair Response to 1-TIME Restoration

103 Detroit River Response to 1-TIME Restoration

104 Lake Erie Response to 1-TIME Restoration

105 Niagara River + Welland Canal Response to 1-TIME Restoration

106 Lake Ontario Response to 1-TIME Restoration

107 Lake Ontario Outflow Response to 1-TIME Restoration

108 Jetty1 Response to 1-TIME Restoration

109 Monthly metric Res. Lv.SCERONJETSCRDRNiR cm cms Max decrease to base case Max decrease to base case min Max increase to base case Max increase to base case max Time MH Restoration Short-Term Downstream Effects STATIC vs. DYNAMIC 77A

110 STATIC 77A vs. Dynamic 77A Restoration on MH (cm)Bottom level of SC (m)Bottom level change in SC to the base case (cm) 0 (base case)

Substitution for slides: 21, 33, 72, 89

112 Monthly Metric 15 years after rest. Res. Lv.SCERONJETSCRDRNiRONout cm cms Max decrease to base case Max decrease to base case min Max increase to base case Max increase to base case max Time MH Restoration – STATIC 77A Short- Term Downstream Effects

Monthly Metric 25 cm restoration Scenarios SCERONJetSCRDRNiR cmcms Max decrease to base case 1-Time Staged Max decrease to base case min 1-Time Staged Max increase to base case 1-Time Staged Max increase to base case max 1-Time Staged Time vs. Staged 25cm MH Restoration – STATIC 77A Short-Term Downstream Effects

114 MetricScenario SCERONJETSCRDRNiRONout cmcms Maximum monthly lake level decrease compared to base case (no-restoration) Annual average decrease to the base case in the first year after restoration

115 1-Time MH Restoration Short-Term Downstream Effects STATIC vs. DYNAMIC 77A Monthly Metric 15 years after rest. Res. Lv.SCERONJETSCRDRNiRONout cm cms Max decrease to base case Max decrease to base case min Max increase to base case Max increase to base case max