Fluvial Design Guide - Chapter 2 Background

Hydrology

Rob Lamb, Duncan Faulkner and Maxine Zaidman

This chapter provides comprehensive coverage of the theory and practice of quantifying the discharge (flow) in a watercourse for the purposes of designing or assessing the hydraulic performance of works in the fluvial environment. It provides guidance on both low flows and flood flows.

The processes involved in flood hydrology are explained, covering rainfall and snowmelt, runoff generation (natural and urban catchments), and the influence of storage, groundwater and tides.

Sources of data are described and there is guidance on where to find appropriate data. The relevance of catchment descriptors and flood history are outlined.

The concepts behind the estimation of floods for fluvial design are clearly spelt out, including probability and return period, frequency analysis, pooled analysis, the design event approach, continuous simulation, and the use of routing models. Guidance is also provided on special cases such as urban catchments and small catchments.

Low-flow analysis is covered because of its importance to the investigation of the environmental performance of fluvial interventions. This section includes advice on flow duration curves and the naturalisation of flow data.

There is an important section on confidence and uncertainty – crucial issues that have often been poorly understood by designers in the past. There is also guidance on the impacts of climate change and land management change.

Chapter Structure

2.1 Key issues

2.2 Processes in flood hydrology

2.3 Sources of data

2.4 Design flood estimation concepts

2.5 Special cases

2.6 Low flow analysis

2.7 Confidence and uncertainty

2.8 Climate and land management change impacts

Key references

Other references

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A discharge measuring structure in flood conditions

Rob Lamb

R Lamb
Technical Director
JBA Consulting
South Barn, Broughton Hall, Skipton, North Yorkshire BD23 3AE
www.jbaconsulting.co.uk

Rob Lamb is a hydrologist specialising in flood risk analysis methods, including rainfall-runoff models, statistical risk analysis techniques and 1D and 2D hydraulic models. He has published widely with over 30 peer-reviewed journal papers, commissioned research reports and textbooks.

Duncan Faulkner

D S Faulkner
Technical Director
JBA Consulting
South Barn, Broughton Hall, Skipton, North Yorkshire BD23 3AE
www.jbaconsulting.co.uk

 01756 799919  01756 799919

Duncan Faulkner is a hydrologist who specialises in flood estimation and modelling of rainfall and runoff. He was a member of the Flood estimation handbook research team and wrote Volume 2, which deals with rainfall frequency estimation. Since joining JBA in 1999 he has continued his involvement in hydrological research, as well as carrying out numerous consultancy projects in the UK and Ireland, mostly involving aspects of flood risk management. He also has experience of hydraulic modelling of both rivers and groundwater.

Maxine Zaidman

M D Zaidman
Principal Hydrologist
JBA Consulting
South Barn, Broughton Hall, Skipton, North Yorkshire BD23 3AE
www.jbaconsulting.co.uk

 01756 799919  01756 799919

Maxine Zaidman is a consultant hydrologist with a background in water resource and flood risk management. She has significant expertise in low-flow hydrology and has authored several technical publications on the subject.