A Tug‐of‐War Within the Hydrologic Cycle of a Continental Freshwater Basin

Abstract

The past decade was the wettest on record for much of central and eastern North America. Near the beginning of this period of regional water abundance, however, drought conditions reinforced concerns that high temperatures and evapotranspiration foreshadowed a persistent imbalance in the hydrologic cycle characterized by water loss. These fluctuating hydrologic conditions were manifest by water level variability on the Laurentian Great Lakes, the largest system of lakes on Earth. We show that, during this period, the two dominant hydrologic forces acting directly on the vast surfaces of the lakes, overlake precipitation and overlake evaporation, have evolved differently. More specifically, we find that overlake precipitation has risen to extraordinary levels, while overlake evaporation diminished rapidly in 2014 (coinciding with a strong Arctic polar vortex deformation). Our findings offer a new perspective on the impacts of competing hydrologic forces on large freshwater systems in an era of climate change.

Strategies for Adapting Great Lakes Coastal Ecosystems to Climate Change

“…Climate factors that contribute to periods of low water levels include periods of drought, decreased inputs from tributaries, and increased evaporation caused by higher temperatures and decreased ice cover (IUGLS 2012, Wuebbles et al 2019). Higher average precipitation in the Great Lakes region and increased heavy precipitation events leading to increased stream inputs, may contribute to high lake level periods (Cherkauer & Sinha 2010, IUGLS 2012, Gotkowitz et al 2014, Wuebbles et al 2019, Gronewold et al 2021. Climate change may also cause more intense and frequent storm events, which are associated with higher wind speeds, increased waves, and storm surges (Mackey 2012, Magee et al 2021).…”

Evaluating essential processes and forecast requirements for meteotsunami-induced coastal flooding

“…12b). Recent studies suggest that the water level rise was caused by the combination of increased precipitation and decreased lake evaporation since 2013-2014 (Gronewold et al 2021). Regional climate projections suggest the trend of rising water may continue into the future (Notaro et al 2015;Kayastha et al 2021).…”

Recent changes in Great Lake hydrologic variability: an artifact of chance or a robust change?

“…Examples include shifts in shoreline erosion patterns (Gronewold and Stow, 2014;Davidson-Arnott, 2016), shipping costs (Millerd, 2010;Lindeberg and Albercook, 2000;Wang et al, 2012), tourism and recreation (Wall, 1998;Hartmann, 1990), and risks to critical infrastructure like water resource management (de Loe and Kreutzwiser, 2000), hydropower (Meyer et al, 2017), and toxic waste facilities (Environmental Law and Policy Center, 2022). Researchers and the public alike have thus been captivated by the rapid transition of Great Lake levels between record low and high lake levels and the resultant impacts (e.g., Gronewold et al, 2021;Egan, 2021). This interest is further motivated by the observed and projected intensification of the hydrologic cycle due to anthropogenic climate change (IPCC, 2021;Seager, 2014).…”

“…This interest is further motivated by the observed and projected intensification of the hydrologic cycle due to anthropogenic climate change (IPCC, 2021;Seager, 2014). Within this context, Gronewold et al (2021) presented evidence of rising lake level variability and described the situation caused by this hydrologic cycle intensification as a "continental-scale hydrological tug-of-war" between changing water balance components. Lake levels of large lakes are dominated by three net basin supply (NBS) components: overlake precipitation, overlake evaporation, and basin runoff, where the collective balance of these three components largely determine Great Lakes levels (Δ lake storage = p overlake + r basin -e overlake ) (Gronewold et al, 2021).…”