A series of structures was built along Widden Brook to trap sandy bed load as part of a river rehabilitation project. Stock-proof fencing of the riparian corridor was also carried out. The combination of in-stream structures and riparian revegetation has successfully sequestered large volumes of sand over the last six years, causing a substantial reduction in downstream sand supply. Downstream channel response to sand sequestration has included up to 1 m of bed degradation, channel contraction to less than half of the initial channel width, formation of marginal in-channel benches, reformation of a well-defined, rhythmically-spaced pool-riffle sequence and creation of a partially gravel-armoured bed surface. Sand storage in the study reach has starved the river immediately downstream, inducing bed erosion and the size-selective transport of sand and fine gravel. Residual pool depths now store four times the volume of water that was present before the start of river rehabilitation.
International Symposium on Sediment Dynamics in Changing Environments. Sediment Dynamics in Changing Environments (Christchurch, NZ 1-5 December, 2008) p. 576-583