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On the Usefulness of Hydrologic Landscapes for Hydrologic Modeling and Water Management
Citation:
Sawicz, K., S. Leibowitz, C. Jones, R. Comeleo, AND P. Wigington, Jr. On the Usefulness of Hydrologic Landscapes for Hydrologic Modeling and Water Management. World Environmental and Water Resources Congress, West Palm Beach, FL, May 22 - 26, 2016.
Impact/Purpose:
EPA’s Western Ecology Division has published and continues to expand a framework for defining areas of the landscape that are hypothesized to have similar hydrologic responses. These hydrologic landscapes (HL) were developed to help characterize duration of flow in non‐navigable streams, to examine how non‐navigable streams influence and contribute to the integrity of navigable waters. A revised HL classification scheme was developed for over 10,000 assessment units (the fundamental unit of area for an HL) within the Pacific Northwest (PNW; Oregon, Washington, and Idaho). The HLs were developed using the National Hydrography Dataset Plus’s catchments that are comprised of classification components describing climate, climate seasonality, aquifer permeability, terrain, and soil permeability. Aggregation of the PNW HL assessment units to the watershed-scale was then completed for the PNW through use of a collection of clustering approaches. This approach was then validated by comparing the resulting HL-derived clustering approaches to the hydrologic response as defined by characteristics of the streamflow time series. The result generated from this study was that the HL assessment units with greater moisture surplus or deficit formed a stronger connection between watershed-scale PNW HL and hydrologic response. The next step was to investigate the usefulness of the information with regard to hydrologic modeling calibration and model structure selection. The hypothesis that we set forward for this study is that hydrologic response, as inferred from the aggregation of HL assessment units, will improve the accuracy of predictions set by hydrologic models. A selection of streamgage stations and their associated watershed area across the PNW were modeled with lumped and semi-distributed modeling structures. This increase in accuracy of hydrologic models could aid water managers and other stake holders in their ability to manage water supply and flood control. This presentation will include a primary product of the model calibration and structure to present one of the many possible use cases for the PNW HLs generated under ACE task MA-1 249.
Description:
Hydrologic Landscapes (HLs) are units that can be used in aggregate to describe the watershed-scale hydrologic response of an area through use of physical and climatic properties. The HL assessment unit is a useful classification tool to relate and transfer hydrologically meaningful information between different watersheds without access to streamflow time series. A revised HL classification scheme was developed for over 10,000 assessment units (the fundamental unit of area for an HL) within the Pacific Northwest (PNW; Oregon, Washington, and Idaho). Aggregation of the PNW HL assessment units to the watershed-scale was then completed for the PNW through use of a collection of clustering approaches. This approach was then validated by comparing the resulting HL-derived clustering approaches to the hydrologic response as defined by characteristics of the streamflow time series. The result generated from this study was that the HL assessment units with greater moisture surplus or deficit formed a stronger connection between watershed-scale PNW HL and hydrologic response. The next step was to investigate the usefulness of the information with regard to hydrologic modeling calibration and model structure selection. The hypothesis that we set forward for this study is that hydrologic response, as inferred from the aggregation of HL assessment units, will improve the accuracy of predictions set by hydrologic models. A selection of streamgage stations and their associated watershed area across the PNW were modeled with lumped and semi-distributed modeling structures. This increase in accuracy of hydrologic models could aid water managers and other stake holders in their ability to manage water supply and flood control.