Historic and projected climate change in addition to constantly evolving agricultural practices make it difficult to disentangle the influence of climate and land use decisions on Canadian Prairie streamflow regimes and water availability. This paper aims to describe the development and application of a basin classification-based virtual model platform that can be used to enhance understanding of how climate and wetland drainage each control Prairie basin hydrology. Each 100 km2 basin in the Canadian Prairie ecozone was classified into one of seven types using a hierarchical clustering of principle components. The modelling platform has been applied to investigate the hydrological sensitivity of two Prairie basin classes (High Elevation Grasslands and Pothole Till) to changes in climate and wetland extent. The experiments revealed that snowpacks are highly sensitive to changes in climate, and this varies geographically and between the two classes. Spring maximum snow water equivalent can decrease 9% per degree °C of warming, but this can be offset with increases in mean annual precipitation. Wetland drainage enhances annual streamflow volume, more so during wet conditions. The platform is designed to expand and provide linkages to water chemistry, groundwater and biodiversity models to generate information on how multiple systems may respond to stress. These results are being developed in partnership with stakeholders, and communicated to decision-makers to inform agricultural beneficial management practices and wetland management. n Presented during S4: Novel approaches to quantifying synergistic interactions between climate and land-use change on prairie-pothole wetlands II, 6/1/2021 10:55AM- 12:45PM ET
NEW INSIGHTS ON THE ROLE OF WETLANDS IN CONFERRING WATERSHED HYDROLOGIC RESISTANCE Creed, Irena, University of Saskatchewan Paltsev, Aleksey Ameli, Ali Lane, Charles Golden, Heather Leibowitz, Scott Hydrologic resistance is a watershed’s ability to absorb or contend with disturbances while maintaining or quickly recovering hydrologic functional traits. Here, we explore the importance of vulnerable waters – such as wetlands – in conferring a watershed’s hydrologic resistance at national scales. We used a framework that quantifies and compares the hydrologic values of wetlands of different types (surface/subsurface), locations (far or near to stream), and connectivity (low versus 226 Wetland Science & Practice July 2021
high connectivity) to explore the relationships between wetlands and hydrologic resistance in relatively undisturbed catchments throughout the conterminous United States. We measured hydrologic resistance as the degree to which discharge (Q) is coupled with precipitation (P) (i.e., the slope of the P vs. Q correlation) – watersheds that store water and release it gradually to the stream have a high resistance (low P-Q correlation). In contrast, watersheds that do not hold water and release it quickly to the stream have low resistance (high P-Q correlation). We considered factors that influence the way a watershed collects, stores and releases water, and links P to Q. We included: (1) “distal factors” such as estimated water balance as indicated by the theoretic energy (potential evapotranspiration (PET)/P) and water (actual evapotranspiration (AET)/P) limits and synchrony between P and temperature (T) phases; and (2) “proximal factors” [e.g., the potential volumetric storage capacity of a wetland, the residence time of water stored within it, the location of a wetland to a nearby stream – and its hydrologic connectivity to the stream]. As expected, we found that for watersheds that are in phase, where at the extremes, peak P and peak temperature (T) are in July, low connectivity wetlands conferred higher hydrologic resistance. However, not expected, we found that for watersheds that are out of phase, where at the extremes, peak P is in January, and peak temperature is in July, low connectivity wetlands conferred lower hydrologic resistance. Wetlands vary in the manner in which they affect hydrologic resistance, based on their hydrologic connectivity and P and T synchrony. Our findings led us to develop new conceptual models of the role of wetlands in conferring watershed hydrologic resistance that are being further explored. n
Policy Presented during CS5: Worldly Wetlands II, 6/3/2021 6:55PM 8:45PM ET
TRANSBOUNDARY WETLANDS: EXPLORING FORMAL MECHANISMS FOR COOPERATION Rosenblum, Zoe, Oregon State University and IHE-Delft Institute for Water Education Despite increased understanding of the benefits of wetlands, global wetland area continues to decrease. Wetlands are being lost at an alarming rate, and with them, biodiversity, floodwater storage, water purification, and countless other functions. There is little information available about mechanisms to manage transboundary wetlands.
