Great Lakes Water Levels

Transcription

1 Great Lakes Water Levels What are the factors that influence Great Lakes water levels? What is the normal range of Great Lakes water levels? What about Lakes Michigan-Huron? Environmental and Socio-Economic Impacts Climate Variability and the future Water levels go up, water levels go down.

2 Great Lakes Cross Section Lake Superior ft Lakes Michigan Lake and Huron St. Clair ft Lake Erie ft Niagara Falls Lake Ontario 925 ft 752 ft 212 ft ft St. Lawrence River 20.6 ft 1333 ft 804 ft Distance in Miles Great Lakes Basin Framework Study

3 What Drives Water Level Change? Climate Precipitation + Runoff Evaporation = NBS Seasonal changes in climate (annual) Inflows and Outflows Connecting Channel Flows between Lakes Water-Level Regulation Diversions (into and out of basin) Consumptive Uses Wind and Storm Events (short term)

4 Great Lakes Water Balance Lake water levels are climatically driven by seasonal changes in precipitation and evaporation. Evaporation is affected by surface water temperature, wind speed, and presence/absence of ice cover. Inflows/outflows via connecting channels between Lakes St. Marys River St. Clair/Detroit River Niagara River St. Lawrence River mm on the Lake Surface mm on the Lake Surface Source: Great Lakes Environmental Research Laboratory Runoff Precip Evap Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Month Month Net Basin Supply (P + R - E) Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

5 Hydrological Components Lake Superior 56% precipitation 40% runoff 4% diversions % evaporation 57% outflow Lake Michigan- Huron 39% precipitation 34% runoff 27% inflow % evaporation 68% outflow 1% Chicago diversion Long Lac/ Ogoki 154 m 3 /s (5400 cfs). St. Marys River 2110 m 3 /s Hydrologic Values Lake Ontario 79% inflow 15% runoff 6% precipitation % outflow 7% evaporation St. Lawrence 7060 m 3 /s Lake Erie 79% inflow 11% precipitation 10% runoff % outflow 11% evaporation Chicago Diversion 91 m 3 /s (3,200 cfs) St. Clair/Detroit River 5360 m 3 /s Niagara River 5780 m 3 /s Courtesy IUGLS

6 Diversions and Impacts Lake Superior +9 cm (+3.5 ) 0 0 Net +9 cm (+3.5 ) Long Lac/ Ogoki 154 m 3 /s (5,400 cfs). Great Lakes Connecting Channel Diversion in Diversion out Lake Michigan- Huron Sault St. Marie Control Structures Diversion within +11 cm (+4.3 ) -6 cm (-2.4 ) -4 cm (-1.6 ) Net +1 cm (+0.4 ) Cornwall Massena Control Structures Lake Erie +7 cm (+2.8 ) -4 cm (-1.6 ) -12 cm (-4.7 ) Net -9 cm (-3.5 ) St. Clair River Welland Canal 244 m 3 /s (8620 cfs) Chicago Diversion 91 m 3 /s (3,200 cfs) Courtesy IUGLS

7 Lake Ontario Regulation Begins Basinwide Drop in GL Water Levels

8 August 2013 Forecast

9 Environmental Low Water Impacts Shifts in shoreline position/location (loss/gain wetlands) Loss of hydraulic connectivity (Georgian Bay wetlands/tributaries) Changes in seasonal magnitude, timing and duration Altered tributary flows and Lake circulation patterns Degradation of water quality Socio-Economic Commercial Shipping Recreational Boating/Marina Operation Coastal hazards (erosion and flooding) Public Health and Safety (water quality) Property Access

10 Glacial Isostatic Adjustment Glacial Isostatic Adjustment (GIA) in northern Lake Huron and Lake Superior exacerbates impact of low Lake Michigan-Huron water levels. Rates are cm/100 years relative to Lake outlet elevations.

11 IUGLS - Lake Michigan-Huron Water Levels Long-term change in the head between Lakes Michigan-Huron and Lake Erie. Possible erosion/increased conveyance in St. Clair River due to dredging and sand mining? 1962 last time major dredging occurred on St. Clair River (subsequent maintenance dredging lower reaches only). Level Restoration Scenarios Rationale 0 cm (0.0 ) No change 10 cm (3.9 ) Post 1962 dredging 25 cm (9.8 ) Plus 27-ft channel ( ) 40 cm (15.7 ) Plus 1930 mining & 25-ft channel 50 cm (19.7 ) All alterations since A 2 No compensation for St. Clair River dredging (25 and 27 ft channels). 8

12 IJC Recommendations - St. Clair River Recommends further investigation to restore Lake Michigan-Huron water levels Recommends that the governments undertake further investigation of options to increase water levels in Lakes Michigan-Huron by 13 to 25 cm (about 5 to 10 inches). Investigation to be funded, undertaken, and concluded as quickly as possible. Criteria and Deliverables Explore options that would provide relief during low water periods, but not exacerbate future high water levels, and Provide a comprehensive binational benefit-cost analysis and a detailed environmental impact study of potential structural options.

13 IJC Recommendations - Lake Superior IJC Endorses Lake Superior Regulation Plan Plan 2012 delivers robust performance over a wide range of possible hydrologic conditions. Preparing supplemental Orders of Approval to implement Plan IJC Recommendations - Multi-Lake Regulation Further study of Multi-Lake Regulation is not warranted. Climate uncertainties, high cost, institutional requirements, and environmental concerns Regulation of Great Lakes Water Levels and 1993 IJC Levels Reference Study reached similar conclusions.

14 IJC Recommendations - Adaptive Management Endorses implementation of a comprehensive Adaptive Management approach supported by Science and Monitoring Established International Great Lakes St. Lawrence River Adaptive Management Task Team to further develop a detailed adaptive management plan. Strengthening hydroclimate monitoring and modeling; Ongoing risk assessment; Ensuring more comprehensive information management and outreach; Improving tools and processes for decision makers; Collaborative regional adaptive management study for addressing water level extremes; and Integration of water quality and quantity modeling activities.

15 Climate Variability and Water Levels According to the most recent climate models, the climate in the upper Great Lakes basin during the next years is likely to be characterized by: Increase in storm severity - an increase in precipitation and more frequent and intense storms (weather variability); Increase in evaporation - an increase in lake evaporation resulting from higher surface water temperatures and wind speeds, lack of winter ice; Change in seasonal timing - increased water supply during winter/spring months accompanied by larger decreases in supply during summer/early fall resulting in slight overall annual declines.

16 Future Great Lakes Water Levels Great Lakes water levels are anticipated to remain below long-term historic mean water levels, but generally within the range of historic water levels. Anticipate more extreme and variable water level events, i.e. anticipate both low and high water level regimes that may exceed historic thresholds, both low and high. Lower Lake Michigan-Huron water levels may continue to occur irrespective of St. Clair River compensation. St. Clair River compensation may reduce, but not eliminate potential low water-level impacts on Lakes Michigan-Huron. Adaptive management is still required to plan for (and respond to) extreme water level events whether or not St. Clair River compensation is implemented.

17 Questions?

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19 Late Holocene Lake Levels - Lakes Michigan/Huron Historical record Measured Inferred 177 ~160-year fluctuation Algoma phase ~30-year fluctuation Nipissing II phase Historical average ( ) v Calendar year before AD BC Year Courtesy Todd A. Thompson - Indiana Geological Survey

20 August 2013 Forecast

21 Lake Superior Water Level Regulation Sabin Rule ( ) Rule P-5 ( ) Rule of 1949 ( ) 1955 Modified Rule of 1949 ( ) SO-901 ( Guide ) Plan 1977 ( ) Plan 1977A (1990-present) Plan 2012 proposed

22 Water Level (m, IGLD 85) Water Level (m, IGLD 85) Plan 77A and PreProject Lake Superior Level Pre-Project Plan 77A Lake Michigan-Huron Level

23 St. Clair River Restoration

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