Impacts of directional land cover change on runoff across reference basins in the conterminous United States
Abstract
Land cover change impacts hydrology from field to regional scales, through altering the ratio of rainfall partition into evapotranspiration and runoff. Several studies have been focused on examination of impact of land cover and climate change on hydrology over the basins with substantial human interference; however, basins with minimal human interference have been studied less. In addition, limited study has developed the relationship between the directional land cover change and runoff across low human interference basins, which is an indicator of water availability at those basins. In this study, we investigated the impacts of directional land cover changes in runoff coefficient (RC) and runoff volume across 603 low human interference reference basins in the conterminous United States (CONUS). The results indicate that basins across the northeast and northwest regions of the CONUS had significant increasing trends on runoff and RC, and basins in the southern region had decreasing trends. One percent increase in basin area from grassland and shrubland combined to forest was associated with ~4% decrease in RC across basins with decreasing RC trend. Similarly, one percent increase in basin area from forest to a combined grassland and shrubland was associated with ~1% increase in RC across basins with increasing RC trend. Runoff volume decreased (increased) by ~25×106 m3 yr-1 (~9×106 m3 yr-1) across basins with decreasing (increasing) trends on runoff and RC. When relating runoff volume to the area of directional land cover changes, 1 km2 increase from grassland and shrubland to forest resulted in ~530,000 m3 decrease on runoff volume across basins with decreasing trends. In contrast, 1 km2 increase from forest to grassland and shrubland increased runoff volume by ~200,000 m3 across increasing trend basins. Basins in the southern region of the CONUS were more impacted to runoff parameters (RC and runoff volume) from directional land cover changes compared to the basins in the northern region. The findings of this study are useful for planning and managing water availability for sustainable and adaptive water resources management at regional scales.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMH094...08K
- Keywords:
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- 0402 Agricultural systems;
- BIOGEOSCIENCES;
- 1632 Land cover change;
- GLOBAL CHANGE;
- 1803 Anthropogenic effects;
- HYDROLOGY;
- 1836 Hydrological cycles and budgets;
- HYDROLOGY