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Effects of digital elevation model data source on HSPF-based watershed-scale flow and water quality simulations
Maryam Roostaee1, Zhiqiang Deng2
1AECOM, New Orleans, LA, 70112, USA.
Environmental Science and Pollution Research International
|December 1, 2022
Summary
Digital elevation model (DEM) source significantly impacts watershed modeling results, more than resolution. Uncertainties are higher in low-gradient watersheds, affecting sediment and nitrate simulations.
Area of Science:
- Environmental Science
- Hydrology
- Geospatial Analysis
Background:
- Digital Elevation Models (DEMs) are crucial for watershed modeling and environmental management.
- Understanding the impact of different DEM data sources on model outcomes is limited.
- Variations in DEM sources can influence simulated hydrological and water quality parameters.
Purpose of the Study:
- To investigate how DEMs from three different sources affect simulated flow, nitrate, phosphorus, and sediment using the BASINS/HSPF model.
- To quantify the uncertainties introduced by DEM sources compared to DEM resolution.
- To analyze the influence of watershed characteristics (slope) and delineation methods on DEM source-induced uncertainties.
Main Methods:
- Utilized the BASINS/HSPF watershed modeling system.
- Compared simulation results using DEMs from three distinct data sources.
- Evaluated uncertainties related to DEM source versus DEM resolution.
- Assessed the impact on different hydrological and water quality parameters (flow, NO3, P, sediment).
- Examined the influence of watershed slope and delineation methods (automatic vs. manual).
Main Results:
- DEM source-induced uncertainties were greater than DEM resolution-induced uncertainties.
- Low-gradient watersheds exhibited higher uncertainties with automatic delineation compared to high-gradient watersheds.
- Sediment and nitrate (NO3) concentrations showed the highest and lowest sensitivity to DEM sources, respectively.
- Manual watershed delineation reduced but did not eliminate simulation uncertainties.
Conclusions:
- DEM source is a critical factor influencing watershed modeling accuracy.
- High-precision DEMs (e.g., NED) are recommended, particularly for low-gradient or flat watersheds.
- Modelers should carefully consider DEM source selection based on watershed characteristics and available resources to minimize simulation uncertainty.
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