Examination of the declining trend in suspended sediment loads in the Rhine River in the period 1952-2016
MARCEL VAN DER PERK, CUT AYU TIARA SUTARI, HANS MIDDELKOOP
Department of Physical Geography, Utrecht University, P.O. Box 80115, 3508 TC Utrecht, The Netherlands; e-mail: m.vanderperk@uu.nl
0.0 1.0 2.0 3.0 4.0 5.0 6.0
1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016
Annual suspended sediment load (106 t y-1 )
0 10 20 30 40 50 60
1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016
Discharge-weighted average SSC (mg l-1 )
0 10 20 30 40 50 60 70 80 90 100
0 1000 2000 3000 4000 5000 6000 7000 8000
SSC (mg l-1 )
Discharge (m3 s-1)
1952-1959 1960-1964 1965-1969 1970-1974 1975-1979 1980-1984 1985-1989 1990-1994 1995-1999 2000-2005 2006-2010 2011-2016
Introduction
Sediment loads have decreased drastically in rivers worldwide during the past decades. The
Rhine River is no exception and also conforms this global trend. To quantify this declining trend of
suspended sediment loads in the Rhine River, we re- examined the annual suspended loads at the Lobith monitoring station near the Dutch-German border for the period since the start of the start of regular monitoring of suspended sediment concentrations (SSC) in 1952 until present (2016).
Conclusions
• The annual suspended sediment load has decreased by 70% since 1952.
• Since about 2005, the sediment load seems to have stabilised.
• The discharge-weighted average SSC show a
similar, but more consistently declining trend between 1960 and 2005.
• The 5-year rating curves reveal that the decline in average SSC becomes particularly manifest at low discharges.
• The rating curves can roughly be classified into three groups. Major shifts in the sediment rating
curves occurred around 1980 and around 2000.
• The identification of the precise causes will be subject of future study.
Suspended sediment load Discharge-weighted average SSC
Sediment rating curves
Approach
1) Power-law sediment rating curves
(SSC = a Qb) were fitted for approximately 5 year- periods
2) Annual suspended sediment loads and
discharge-weighted average SSC at the Lobith monitoring station were estimated using:
- daily discharge data (meausred) - daily SSC
- pre 1989: 5-year sediment rating curve based on bi-weekly SSC measurements - post-1989: daily measurements
