An On-Line River Categorisation Tool

UNDERSTAND YOUR RIVER – AN ON-LINE RIVER ATEGORISATION OOL C T Figure 2. The successful River Restoration workshop that JBA ran in May 2012 brought to sharp relief that there is a vast gap in data, information and material availability relating to our understanding of River types natural processes in rivers and on floodplains. This means that many attempts at river restoration and naturalisation remain based around a limited overall understanding utilising a narrow set of Step-pool Description approaches developed largely for un-reactive low gradient heavily modified river channels. Step-pool river reaches are often composed of large boulder groups, forming steps separated by pools. The pools contain finer sediment. The channel is JBA are developing a website detailing the findings of the workshop and providing information and often stable and the channel gradient is steep. Typical features guidance on the character and functioning of rivers in the UK synthesised from academic research Typical features found in this river system include step-pools and rapids. Flow regime (Figure 1) and field experience (Figure 2). Common flow types include chutes and turbulent flow interspersed with pools. Figure 1. Braided Description Braided river reaches are rare in the UK. They occur in areas of high gradients with high bedload. The channel is characterised by a number of threads, which can be highly dynamic particularly during larger floods. Typical features Typical features found in this river system include rapids, riffles, pools and cut-off channels. Flow regime Common flow types include chutes. Rapid Wandering Description A wandering channel type has the characteristics of a braided and active single-thread system , with a smaller bed material size, a shallower slope and wider valley floor. Typical features Typical features found in this river system include sequences of bars, pools, riffles, rapids and runs. Flow regime Common flow types include riffles (more ripples), pools and runs (fewer ripples). Riffle Figure 3. Discussion during the workshop sessions suggest restoration successes are poorly reported and so fail to inspire other projects. Many mistakes could also have been avoided or learnt from, if more was known about previous restoration attempts. The attendees at the workshop came from across a wide spectrum of river restoration practitioners with various levels of experience and knowledge. However, they all agreed that appreciation and understanding of the hyromorphological, ecological and hydrological processes that are typical for a particular river reach is crucial, but not sufficiently understood (Figure 3). Figure 4. The JBA Trust are developing further web based material linked to river restoration (Figure 4). All material can be found at www.jbatrust,org. Please contact the poster authors by email with any requests or suggestions to improve the site. Sebastian Bentley1, George Heritage2 1JBA Consulting, Magna House, South St, Atherstone, Warwickshire CV9 1DF [email protected] 2JBA Consulting, Bank Quay House, Sankey Street, Warrington, WA1 1NN [email protected].

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