A national-scale framework for mapping flood-regulating ecosystem services in cold and cryosphere-influenced regions

Quantifying and visualizing how natural landscapes regulate floods remains a challenge for continental- and national-scale modelling. Few frameworks exist that incorporate both hydrological processes and ecosystem functions to identify where landscapes provide natural flood protection, and even fewer are applicable to regions where cryospheric processes strongly influence hydrology. Using Canada as the study area, this work presents an emerging national-scale modelling framework designed to quantify and map flood-regulating ecosystem services (FRES) using open-source global hydrological datasets.

The presented workflow utilizes sub-basin delineations from HydroBASINS and associated attribute layers from HydroATLAS to parameterize surface and subsurface hydrological characteristics. First, important indicators such as vegetation cover, land use, slope, and soil properties are synthesized into a comprehensive indicator to represent landscape capacity for runoff attenuation. Then, to improve applicability to cold environments, additional variables representing snow, glaciation, and permafrost are incorporated to reflect cryospheric controls on flood-regulating processes. 

To explicitly link ecosystem functions to hydrological processes, an eco-hydrological model adapted from global hydrography concepts is being implemented. This routing approach traces upstream contributions of flood-regulating capacity through connected river networks, allowing downstream flood risks to be evaluated against upstream landscape properties. The resulting maps can identify sub-basin hotspots where natural landscapes are expected to provide disproportionate flood protection benefits. These outputs also facilitate multi-scale analysis of FRES through the aggregation of FRES indicators from sub-basin to national extents by utilizing the hierarchically nested sub-basin structure of HydroBASINS.

The proposed approach aims to provide a scalable and tractable workflow that bridges hydrological reasoning with ecosystem service assessment at the national and continental scale. Ultimately, this framework will serve as a foundation for directly including natural flood protection into large-scale water management, conservation planning, and climate adaptation strategies across Canada and other cold-region contexts.