There are several mapping products available that depict areas susceptible to groundwater flooding; however, they are not comparable in detail to the risk maps developed for fluvial, tidal and surface water flooding that are used by risk management authorities. This paper reports on a new approach to groundwater flood risk mapping for unconfined Chalk aquifers. This approach recognises the synergies between surface water flooding and groundwater flooding once groundwater has emerged at the surface. The volume of groundwater at the surface is modelled by identifying the zone of groundwater emergence and calculating the rate of emergence using a Darcy approach. Flow is then routed using a bespoke two‐dimensional hydraulic model to give the depth and extent of groundwater flooding. These groundwater emergence and routing maps are calibrated on measured groundwater flow and observed flood extents. The maps are anticipated to be used to plan for and manage future groundwater flooding events.

Indicators specifically designed to detect changes in the seasonality, frequency and duration of medium and high river flows have been developed to monitor river flow regimes. Four primary methods to display and interpret the indicator results have been developed to meet the needs of different target audiences. The variability in annual indicator values is accommodated by comparing the probability distributions of the annual values rather than seeking to identify trends in annual values themselves. Changes in the distribution of indicator values are consistent with those anticipated to arise as a result of climate change. This finding is confirmed by calculating the indicators from example flow data for catchments across England and Wales, which has been perturbed to reflect climate change scenario model outputs.

Identifying areas that may be susceptible to groundwater flooding through both hazard and risk maps is a requirement of the EU Floods Directive. For groundwater flooding, hazard maps could show flood extent and depth or water level (velocity would not generally be appropriate) with risk maps additionally showing the potential adverse consequences. The EU Floods Directive allows Member States to limit groundwater flood maps to floods with a low probability, or extreme events. This paper focuses on feasible techniques, available data and current limitations for producing groundwater flood maps that could meet the requirements of the Floods Directive. In addition, to set mapping in the wider context of groundwater flood risk management, advances in data collection and flood warning are also reviewed. Specifically, determining the likelihood and the likely depth of groundwater flooding will be particular challenges where further work will have to build on the advances already made.

The River Ver, a chalk stream in Hertfordshire, was identified as one of the ‘top 40’ low-flow rivers of England and Wales in 1992, and measures to improve flows were subsequently proposed under an alleviation of low flows (ALF) scheme. Consequently, the largest groundwater abstraction within the catchment at Friars Wash was closed, other than for emergencies. The impact of this closure on river flows as measured at a gauge near the outlet of the Ver catchment is evaluated. A range of methods was employed: analyses of hydrographs, flow duration curves, flow percentiles, baseflow index, correlations with data from an analogous catchment and rainfall–runoff modelling. Results suggest an apparent increase in river flow in the 11 years since the closure at Friars Wash; however, this cannot be attributed entirely to the ALF scheme. Further modelling investigations are recommended to support the assessment and to allow more localised effects on stream flow to be investigated.

Whereas fluvial flood risks have, in recent years, become better appreciated and understood, little is generally known about the risks posed by groundwater emergence. To better understand the risks of groundwater flooding, the Department for the Environment, Food and Rural Affairs (Defra) commissioned a scoping study to assess these risks. As part of the scoping study, provisional maps of areas vulnerable to groundwater emergence from consolidated aquifers were produced that reflect the groundwater conditions experienced in the exceptionally wet winter of 2000–2001. These maps, covering all consolidated aquifers of England, are presented as a provisional set of risk maps that, with further refinement, could be utilized in regional planning decisions and for flood risk management.

This paper explores the estimation of river flood frequencies by modelling catchment runoff on a continuous time basis. The work uses the modelling of a sample of British catchments as a basis for generalization in space, such that ungauged sites can potentially be addressed by the method. The principles of the method are outlined. Pilot study hood frequency results for site-specific and for spatially generalized model parameter estimation are discussed. Examples are given of an extension of the method in time to allow estimates to be made of high recurrence interval floods, and of the ability of the method to incorporate changed climatic regimes.

Radiation effects in synthetic and high purity synthetic quartz are examined in a research programme at the GEC Hirst Research Centre concerned with the growth of high purity synthetic quartz and the development of radiation hardened quartz devices. Very high purity synthetic quartz with a low dislocation density has been successfully grown at the Hirst Research Centre. Substitutional aluminium impurity concentrations of 0.05 ppm and dislocation densities of <10 cm−2 have been obtained. Electron spin resonance and infrared absorption studies have confirmed the low impurity levels and overall material quality. Acoustic loss measurements on resonators fabricated from high purity quartz show that the usual Al-Na+ loss peak at 54 K is absent and radiation studies confirm the low substitutional aluminium content with radiation induced frequency offsets of less than 10−13 Hz/rad.

: Radiation effects in synthetic and high purity synthetic quartz are examined in a research programme at the GEC Hirst Research Centre, Wembley England. Low temperature infrared absorption, electron spin resonance (ESR) and variable temperature acoustic loss/crystal parameter measurement are use in a study of radiation induced defects in quartz and their interaction with device properties with the goal of developing radiation hardened quartz crystals. (Author)