| Title | Monitoring groundwater changes in southern Ontario using GRACE satellite gravity measurements |
| Download | Download (whole publication) |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Crowley, J W |
| Source | Regional-Scale Groundwater Geoscience in Southern Ontario: An Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario Geoscientists Open House; by Russell, H A J; Ford, D; Holysh, S; Priebe, E H; Geological Survey of Canada, Open File 8528,
2019 p. 8, https://doi.org/10.4095/313577  Open
Access |
| Year | 2019 |
| Alt Series | Ontario Geological Survey, Open File Report 6349 |
| Publisher | Natural Resources Canada |
| Publisher | Government of Ontario |
| Meeting | Regional-Scale Groundwater Geoscience in Southern Ontario: Open House; Guelph; CA; February 27-28, 2019 |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Regional-Scale Groundwater
Geoscience in Southern Ontario: An Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario Geoscientists Open House |
| File format | pdf |
| Province | Ontario |
| NTS | 30; 31B; 31C; 31D; 31E; 31G; 40; 41A; 41G; 41H/03; 41H/04; 41H/05; 41H/06; 41H/12; 41H/13 |
| Area | Southern Ontario; Great Lakes; Lake Huron; Lake Erie; Lake Ontario; Canada; United States of America |
| Lat/Long WENS | -84.0000 -74.0000 46.0000 41.5000 |
| Subjects | hydrogeology; geophysics; groundwater; aquifers; groundwater resources; satellite geodesy; gravity field; watersheds; hydrologic environment; hydrologic properties; hydrologic budget; surface waters;
lakes; soil moisture; snow; ice; water levels; water wells; correlations; Gravity Recovery and Climate Experiment (GRACE); Canadian National Frameworks Dataset; monitoring |
| Program | Groundwater Geoscience Aquifer Assessment & support to mapping |
| Released | 2019 02 08 |
| Abstract | The Gravity Recovery and Climate Experiment satellite mission(s) (GRACE) have been measuring variations in the Earth's gravitational field since 2002. Changes in groundwater, melting glaciers, ocean
circulation, and large deformations associated with post-glacial rebound, continental tectonics and earthquakes all produce signals that can be detected and monitored. In this talk, I will provide an introduction to the GRACE missions, briefly
mention some new analysis methods being developed at the Canadian Geodetic Survey, and show some new results related to groundwater variations in Southern Ontario. The new method uses watershed regions from the Canadian National Frameworks Dataset to
build mascons (regions of interest) for Canada, ensuring that the boundaries of the numerical method correspond to real hydrological boundaries and reducing leakage between adjacent watersheds. Three distinct mascons are designed using watershed
geometry that include Lake Huron, Lake Erie, and Lake Ontario and estimates of total water storage (TWS) change are obtained using GRACE data from the Center for Space Research (U. of Texas at Austin) spherical harmonic Release 5 dataset. These TWS
estimates are split into a contribution from surface water (SW) change and a common large-scale background signal across Southern Ontario that represents groundwater, soil moisture, snow and ice. The surface water changes are almost entirely due to
lake level changes within the Great Lakes and can be compared to water level observations from gauges on the lakes provided by the Canadian Hydrographic Service. The GRACE derived and observed lake level changes agree well with correlations of 0.95,
0.92, and 0.82 for the Lake Huron, Erie, and Ontario regions, respectively. The amplitudes also agree well and, to our knowledge, this is the first study to effectively detect the changing water levels of the different Great Lakes using GRACE. The
common background signal is found to have peak to peak variations of ~20 cm equivalent water thickness (EWT) and is compared to 301 wells from across Southern Ontario (data from the Provincial Groundwater Monitoring Network). The signals agree well
with a correlation of 0.85. This result has important implications for the relative size and/or dynamics of the groundwater and remaining surface terms (soil moisture, snow and ice). Furthermore, variations in water storage from groundwater are found
to be comparable to variations in water storage from the Great Lakes themselves - highlighting the importance that groundwater plays in any water budget of the Great Lakes system. Comparisons between individual groundwater wells and that of GRACE
reveal the spatial extent of wells that show regional signals (high correlation) and those that show more local variability (poor correlation). Wells that correlate poorly reveal additional spatial patterns and the influence of local topography,
geology, and water usage. |
| Summary | (Plain Language Summary, not published)
Volume of abstracts for Ontario Geological Survey and Geological Survey of Canada groundwater geoscience Open house with Conservation Ontario. |
| GEOSCAN ID | 313577 |
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