Hydrological response of a large-scale mountainous watershed to rainstorm spatial patterns and reforestation in subtropical China.
Sci Total Environ
; 645: 1083-1093, 2018 Dec 15.
Article
en En
| MEDLINE
| ID: mdl-30248833
ABSTRACT
This paper aims to investigate the hydrological response of a large-scale (8973â¯km2) mountainous watershed to different rainstorm spatial patterns and reforestation. Based on 32â¯years of observations, measurements of 184 rainstorm events and 125 sediment-producing events with complete hydrographs were analyzed. The K-means clustering method was used to classify the spatial patterns of rainstorm events in accordance with their event-based spatial rainfall characteristics. The 184 rainstorm events were classified into four spatial patterns, among which the spatial features differ significantly (I) Spatial Pattern I (SPI) includes rainstorms with a low amount of cumulative areal rainfall (27.4â¯mm), the highest spatial variability (0.986), and the highest frequency; (II) Spatial Pattern II (SPII) includes rainstorms of high spatial variability (0.759) and the largest amount of local maximum daily rainfall (106.8â¯mm); (III) Spatial Pattern III (SPIII) includes rainstorms with a medium amount of cumulative areal rainfall (58.7â¯mm) and low spatial variability (0.362); and (IV) Spatial Pattern IV (SPIV) includes rainstorms with the largest amount of cumulative areal rainfall (117.2â¯mm) and the lowest spatial variability (0.313). Vegetation cover in the upper Du watershed was significantly improved after the implementation of the Grain-for-Green project. The average area-specific sediment yields (SSY) for the four SPs were 15.4, 65.5, 55.8, and 286.2â¯tâ¯km-2 before reforestation and decreased to 6.0, 59.3, 43.7 and 89.9â¯tâ¯km-2, respectively, after reforestation. ANOVA (analysis of variance) indicated that reforestation resulted in a significant reduction in runoff coefficient under SPIII and SPIV and a significant reduction in SSY under SPI and SPIV. A hysteresis analysis suggested that the proportion of events with a clockwise loop increased from 64.9% before reforestation to 82.1% after reforestation and that complex loops became less common during 2000-2010 under SPIV, thereby implying a reduced sediment supply.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Sci Total Environ
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos