Regime type equations for mobile gravel‐bed rivers are presented based on data obtained from 62 stable gravel‐bed river reaches in the United Kingdom. Multiple regression techniques are applied to derive equations relating reach average and riffle values of width, mean and maximum depth, slope, velocity, sinuosity and riffle spacing to bankfull discharge, bed and bank material characteristics, valley slope, bank vegetation type and an independent estimate of bankfull bed load transport rates. Although discharge has a dominant control on channel geometry, these equations indicate that bed load discharge also has a significant influence, particularly with regard to channel slope. Bank vegetation has a major control on width and velocity while depth, velocity and slope are strongly affected by bed material size. Reasons for these results are considered in terms of the physical processes controlling channel adjustment. The application of these regime equations is discussed, and particular consideration is giv...

In this paper, a slope stability analysis for steep banks is used in conjunction with a method to calculate lateral erosion distance, to predict bank stability response to lateral erosion or bed degradation. The failure plane angle, failure block width, and volume of failed material per unit channel length may be calculated for the critical case. These parameters define the bank geometry following failure and form the starting point for subsequent analyses. The calculation procedure is illustrated by a worked example. Following mass failure slump, debris accumulates at the bank toe. The debris is removed by lateral erosion prior to further oversteepening or degradation generating further mass failures. Any process‐based model for channel width adjustment must account for the combined effects of lateral erosion and mass instability in producing bank instability. The approach adopted here represents a marked improvement over earlier work, which does not account for changes in bank geometry due to lateral er...

Blue‐Green Infrastructure (BGI) and Sustainable Drainage Systems (SuDS) are increasingly recognised as vital components of urban flood risk management. However, uncertainty regarding their hydrologic performance and lack of confidence concerning their public acceptability create concerns and challenges that limit their widespread adoption. This paper investigates barriers to implementation of BGI in Portland, Oregon, using the Relevant Dominant Uncertainty (RDU) approach. Two types of RDU are identified: scientific RDUs related to physical processes that affect infrastructure performance and service provision, and socio‐political RDUs that reflect a lack of confidence in socio‐political structures and public preferences for BGI. We find that socio‐political RDUs currently exert the strongest negative influences on BGI decision making in Portland. We conclude that identification and management of both biophysical and socio‐political uncertainties are essential to broadening the implementation of BGI and sustainable urban flood risk management solutions that are practical, scientifically sound, and supported by local stakeholders.