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A novel index for assessment of riparian strip efficiency in agricultural landscapes using high spatial resolution satellite imagery

Author:
Novoa, Julio, Chokmani, Karem, Lhissou, Rachid
Source:
The Science of the total environment 2018 v.644 pp. 1439-1451
ISSN:
0048-9697
Subject:
agricultural land, agricultural zoning, aquatic organisms, ecosystem services, filtration, hydrologic factors, hydrologic models, land cover, melting, pollutants, remote sensing, riparian areas, riparian buffers, riparian vegetation, runoff, sediments, snowmelt, soil erosion, spring, stream flow, surface drainage, topography, water quality, watersheds, Quebec, Scandinavia
Abstract:
Riparian strips are used worldwide to protect riverbanks and water quality in agricultural zones because of their numerous environmental benefits. A metric called Riparian Strip Quality Index, which is based on the percentage area of riparian vegetation, is used to evaluate their ecological condition. This index measures the potential capacity of riparian strips to filter sediments, retain pollutants, and provide shelter for terrestrial and aquatic species. This research aims to improve this metric by integrating the ability of riparian strips to intercept surface runoff, which is the major cause of water pollution and erosion in productive areas. In Canada and the Nordic countries, rapid surface drainage from snow melt and spring rains is often practiced to avoid production delays and losses. This reduces the efficiency of riparian buffer strips by promoting soil erosion due to concentrated runoff. A new proposed metric called Riparian Strip Efficiency Index (RSEI), incorporates not only land cover information, but topographic and hydrologic variables to model the intensity and spatial distribution of runoff streamflow, and the capability of riparian strips to retain sediments and pollutants. The research is performed over the La Chevrotière River Basin in the Portneuf municipality in Québec (Canada) using hydrological modeling, land cover and topographic data extracted from very high spatial resolution WorldView-2 imagery as a unique source of inputs. The results show that RSEI provides a better characterization of the ecosystem services of riparian strips in terms of pollutants filtration and prevention of soil erosion in agricultural areas. RSEI will allow a better management of agricultural practices such as drainage and land leveling. Further, it will provide to land managers information to monitor environmental changes and to prioritize intervention areas, which ultimately targets to ensure optimal allocation of private or public funds toward the most inefficient and threatened riparian strips.
Agid:
6098651