A national suitability dataset for infiltration-based sustainable drainage systems

The Floods and Water Management Act 2010, includes the provision for sustainable drainage systems (SuDS) which aim, in part, to reduce flooding and improve water quality. Infiltration-to-the-ground is a key SuDS component that can provide effective and practical opportunities for the attenuation of surface water, however systems must complement ground conditions to ensure effective drainage, stability of ground and protection against groundwater quality deterioration. This paper reports on the development of a national suitability GIS dataset that provides subsurface information that may be useful for the planning and design of effective infiltration-based SuDS, whilst also highlighting those circumstances where infiltration may cause unintended negative consequences including flooding or severe ground instability. The dataset focuses on four key themes: a) severe constraints that preclude infiltration-systems; b) subsurface drainage properties; c) vulnerability of groundwater from infiltration water and d) presence of geological hazards triggered by infiltration. The dataset is populated with a wealth of subsurface data, derived by the British Geological Survey (BGS), enabling rapid assessment of subsurface conditions

Surface water flooding : sustainable drainage to the ground

During the exceptional rainfall events of summer 2007, floods inundated 7,300 businesses and 48,000 homes across the UK (PITT Review) with estimated costs of £3.2 billion. A review of the causes and consequences of these events (PITT review) identified that extreme rainfall and overwhelmed drainage systems led to surface water being a primary cause of flooding. This type of flooding is particularly problematic in urban areas where rapid run-off from impermeable surfaces (roofs, pavements), exceeds the drainage capacity of that area leading to flooding in locations that are difficult to predict. The impacts are not restricted to water volume; the quality of water in receiving watercourses can also be compromised by pollutants entrained in run-off water and sewage contamination derived from Combined Sewer Overflow surcharging

UK Business Investment: Long-Run Elasticities and Short-Run Dynamics

From neoclassical theory output, capital stock and the user cost are cointegrated; capital and investment also (multi)cointegrate through the capital accumulation identity. An investment equation is estimated on UK data using a new capital stock series and a long series for the weighted cost of capital. Assuming CES technology, the elasticity of substitution is well-determined and below unity. Over-identifying restrictions are accepted. The long-run parameter is robust to alternative specifications, but single-equation investment relationships may obscure the dynamics. The Johansen method is over-sized, but outperforms a single equation test for excluding the capital accumulation identity from the investment equation.investment, capital stock, identification, multicointegration

Elections, Fiscal Policy and Growth: Revisiting the Mechanism

This short paper reconsiders the popular result that the lower the probability of getting reelected, the stronger the incumbent politicians’ incentive to follow short-sighted, inefficient policies. The set-up is a general equilibrium model of endogenous growth and optimal fiscal policy, in which two political parties can alternate in power. We show that re-election uncertainty is not enough to produce the popular result. Specifically, re-election uncertainty must be combined with the hypothesis that politicians care about economic outcomes more when in power than when out of power, and - more importantly - that this preference over being in power is ad hoc. That is, if politicians can also choose how much to care about economic outcomes when in and out of power, it is optimal to care the same and hence shortsighted policies do not arise. Therefore, such policies presuppose a degree of irrationality on the part of political parties.politics, fiscal policy, economic growth, general equilibrium

Forecasting using Bayesian and Information Theoretic Model Averaging: An Application to UK Inflation

In recent years there has been increasing interest in forecasting methods that utilise large datasets, driven partly by the recognition that policymaking institutions need to process large quantities of information. Factor analysis is one popular way of doing this. Forecast combination is another, and it is on this that we concentrate. Bayesian model averaging methods have been widely advocated in this area, but a neglected frequentist approach is to use information theoretic based weights. We consider the use of model averaging in forecasting UK inflation with a large dataset from this perspective. We find that an information theoretic model averaging scheme can be a powerful alternative both to the more widely used Bayesian model averaging scheme and to factor models.Forecasting, Inflation, Bayesian model averaging, Akaike criteria, Forecast combining

Urban design and social capital: lessons from a case study in Braunstone, Leicester, UK

A valuable asset in sustainable regeneration is the ‘community’ with their developed networks, bonds and ties or in other words its social capital which is a useful resource. Braunstone in Leicester is typical of many disadvantaged areas in the UK, with persistent socio-economic problems exacerbated by a poor physical setting. With a large regeneration programme funded by the New Deal for Communities coming to a close, we conducted a case study to explore the impact of improved local facilities and the effect of walkability on social capital. The lessons learnt suggests that responding to needs at a finer grain is vital in developing neighbourhoods for social capital such as responding to the needs of different user groups, responding to local patterns of use and needs of micro localities, and improving the perceptions of neighbourhoods. Local facilities and neighbourhood walkablity provides incentives for longer term residency, and facilitates interaction which helps social capital to grow. Accessing services by walking and using public transport proves vital to engage in social activities, while a poor physical environment, lack of accessible services and public transport negatively affects participation in social and leisure activities. Facilities and buildings provide a mediating role in developing social capital in a community, providing opportunity for social interaction which encourages people to reside in an area for longer. Improving connections beyond the neighbourhood is important to help retain people for longer term residency to develop social capital

The glacial and periglacial history of a Middle Pleistocene ice-margin of the British Ice Sheet (BIS) in north Buckinghamshire, England and its influence on geotechnical variability

Resilience is an important factor in the design and operation of new and existing linear infrastructure. Temporal and spatial variability in Quaternary, cold-climate processes, including deposition and weathering of glacigenic sediments and bedrock, subglacial drainage and permafrost development, has resulted in abrupt lateral and vertical anisotropy in the natural geotechnical state of the ground. The ability to anticipate vertical and lateral changes in the physical properties and structure of the shallow subsurface remains a major challenge for geotechnical design. This research uses a combination of field and laboratory techniques to investigate the Middle Pleistocene history of part of north Buckinghamshire and its potential influence on geotechnical variability of till and Oxford Clay mudrocks. The project area was chosen because of its position relative to the proposed route of Great Britain’s second highspeed railway (HS2) and its coincidence with a major Quaternary domain divide between lowland glaciated and non-glaciated, landscape assemblages. A regional database of geotechnical properties and behaviour was constructed. The database was used to describe variability in geotechnical property and behaviour parameters, against which the results of the laboratory investigations were compared. Geotechnical laboratory analyses included single- and multi-stage triaxial tests to determine undrained shear strength parameters, stress paths and strength envelopes. Small-strain stiffness was analysed using Hall effect sensors in triaxial compression. Compressibility behaviour was examined using 1D consolidation tests. This was supplemented by index testing, clay mineralogy analysis, geological field logging and numerical dating of glacigenic sediments using optically stimulated luminescence (OSL) techniques. The results of the laboratory investigation, and database parameters, were interpreted against a national framework of spatial Quaternary Domains which relate similar geological and geomorphological landscape assemblages to their interpreted Quaternary history. The research has demonstrated that there were at least two advances of glacier ice into the area, separated by the development of a large, proglacial ice-dammed lake. OSL dating has determined minimum ages of glacigenic sediment deposition between 145±10 ka and 205 ±13 ka. This implies that the glacial events are at least late Wolstonian in age but the OSL ages do not unequivocally discriminate between Middle Pleistocene glacial events. Direct field evidence for periglaciation occurs in the form of involutions in limestone bedrock and river terrace gravels, sub-horizontal shears in till and Oxford Clay bedrock and frost-cracking within till-derived chalk clasts and micritic limestone bedrock. There are no appreciable differences in the undrained behaviour of the Oxford Clay related to lithology or clay mineralogy. Geotechnical analyses suggest that the Oxford Clay is weaker and more compressible in areas that have not been previously glaciated, compared to those that have. Variability in undrained shear strength and secant shear modulus, G, is seen to be dependent on depth below ground level, regardless of Quaternary Domain. Variability in compressibility and secant effective strength parameters of the Oxford Clay are interpreted to be a function of proximity to a former Middle Pleistocene margin of the British Ice Sheet (BIS). Subglacial and periglacial shearing are interpreted to result in an increase in initial void ratio, increase in compressibility with a corresponding reduction in the secant angle of shearing resistance. Chalk-rich tills are stiff, have low compressibility and have mobilised shear strengths up to 477 kPa. The strength and compressibility variability in the ground between Quaternary Domains and between Oxford Clay and till exposed at the ground surface, has important implications for the design of railway infrastructure which requires geological subgrade stiffness and strength for its long-term performance