The present study aimed at assessing the effects of damming waterways on water
discharge and sediment load variability in a coastal waterway of the Jiulong River,
China. Long term records of water discharge and suspended sediments were divided
into pre and post-damming periods and simple linear regressions were applied to
find out trends. This was coupled by an analysis of short term suspended sediments
data obtained by a field sampling within six months from a representing damreservoir
in the Jiulong River. The results indicate a 7.9% decrease in cumulative
water discharge and a 24% increase in cumulative sediment load from pre to post
damming periods. Mean water discharge in the pre-damming period was
83.9×108
m
3
yr
-1
compared to 83.7×108
m
3
yr
-1
in the post-damming period. Mean
sediment load observed in the pre-damming periods was 6.42×105 Kgyr-1
compared
to 8.02×105 Kgyr-1
in the post-damming period. In addition, dry seasons of predamming
period show high sediment load and low water discharge compared to postdamming
periods. Suspended sediments in the dam-reservoir were observed
increasing with water depth and with distance to dam wall. Long term trends in water
discharge and sediment load might have been influenced by other factors including
increased population, soil conservation, agricultural land use, soil type and forest
cover change in the Jiulong River watershed. Various consequences related to water
quality change, increased nutrient concentrations, sediment delivery to the sea, the
distribution of particulate trace metals and potential for eutrophication were
moderately attributed to the variability of water discharge and sediment load
observed in this study