Determining the relative contributions of climate change and multiple human activities to variations of sediment regime in the Minjiang River, China

Abstract

Abstract In‐stream sediment transport plays an important role in delivery of sediment‐associated terrestrial elements. Investigating the history of fluvial sediment regime responding to changes in natural and anthropogenic driving forces provides a theoretical basis for establishment of optimal strategies on catchment management. The present study aims to systematically detect the patterns of change in sediment load at two key hydrological stations (Pengshan and Gaochang) in the Minjiang River and quantitatively evaluate the relative contributions of regional precipitation change and multiple local human activities to the observed sediment variations. Abrupt change in annual sediment load was detected in 1990 at Pengshan and in 1968, 1980 and 1992 at Gaochang. Compared with the baseline period of 1957–1990, precipitation decline and human activities had respectively contributed to 5 × 10 6 t and 2 × 10 6 t of reduction in mean annual sediment load at Pengshan during 1991–2007. For the entire Minjiang basin, taking 1956–1968 as the baseline period, precipitation decline and human activities had relatively contributed to 10 × 10 6 t and 18 × 10 6 t of reduction in mean annual sediment load at Gaochang during 1969–1980. During 1981–1992, precipitation decline had relatively contributed to 5 × 10 6 t of reduction in mean annual sediment load, but human activities had led to 3 × 10 6 t of increase in mean annual sediment load. During 1993–2009, 13 × 10 6 t and 17 × 10 6 t of reduction in mean annual sediment load may be attributed to precipitation decline and human activities, respectively. Copyright © 2012 John Wiley & Sons, Ltd.