Acoustics of weirs: Potential implications for micro-hydropower noise.

There is great potential for the expansion of the small or micro scale hydropower network. Of the 43 thousand weirs in the UK there are only 500 consented hydro schemes. Planning applications for such schemes require a noise assessment. Noise evaluation of a proposed renewable scheme is often complicated by the turbine sites having distinct noise characteristics in the first instance, which are often caused by the weirs themselves. Three types of weir were studied: Broad Crest weirs were studied in detail; this is complimented by further studies in Flat V and Crump weirs. Flow data was collected for ten sites from the Environment Agency and the National Rivers Flow Archive to assess the collected Sound Pressure Level (SPL) and calculated Sound poWer Level (SWL) in relation to various river flows. Weir head height, width and meteorological data were also collected. It has been shown that the SPL data collection method used was the right choice, as the greatest amplitudes at the water impact interface at all weir types was recorded. SPL and SWL were found to be within a 36e82 dBz and 45e86 dBz range respectively for all weir types. These values can be used in computer simulations of sound propagation. The mean SPL and SWL difference between the weir types are 6.1 dBz and 6.3 dBz. Head height has the greatest effect on SPLs. Attenuation with distance was found to be similar to that of a free field line source in general

Bankfull discharge and recurrence intervals in Irish rivers

Different definitions of the bankfull condition in rivers are based on morphological characteristics, boundary conditions and geometrical properties. Consequently, the magnitude and associated return period of the bankfull discharge can be ambiguous. Knowledge of this discharge is important in index flood estimation and subsequent regional flood frequency analysis. This study investigates bankfull discharges and recurrence intervals at 88 locations in the Irish river network using a combination of surveyed bankfull levels, rating curves and equations and photographic records at the sites in question. Catchments ranged in area from approximately 23 km2 to 2778 km2. Recurrence intervals were determined by fitting generalised extreme value (GEV) distributions to the annual maximum flow series at the sites investigated. These intervals were found to be less than 2 years (the median annual flood) at 42 stations (48%) and less than 2·33 years (the mean annual flood assuming a GEV type 1 distribution) at 47 stations (53%). Higher return periods of between 2·33 and 10 years and 10 and 25 years were observed at a further 20% and 6% of locations respectively. Using multivariate regression analysis, the computed bankfull discharges are correlated with catchment descriptors and three expressions are presented for estimating bankfull flows.Deposited by bulk importPermission granted to archive the final PDF (the version used for publication that subscribers gain access to) but this not available yet. On the webpage that the file is hosted on, please reference the journal homepage (www.geotechnicaljournal.com) and including the text “Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.”TS 01.03.1

Review of tufa deposition and palaeohydrological conditions in the White Peak, Derbyshire UK : implications for Quaternary landscape evolution

This review considers the geological and geomorphological context of tufa barrages that occupy buried valley settings in the Wye catchment, Derbyshire. It describes the potential relationship of the tufa with locations of hypothesised river captures and inception horizon-guided groundwater flow paths. Tufa barrage development is associated with steps in the bedrock, which may be related to knick-point recession during river capture. Broad estimates of valley incision have been calculated from previously dated deposits. These support current interpretations of particularly significant effective base-level lowering during the Anglian and Devensian stages of the Quaternary and have the potential to add to the knowledge of regional uplift histories

Baseline study and risk analysis of landfill leachate - Current state-of-the-science of computer aided approaches

For the successful completion of a risk analysis process, its foundation (i.e. a baseline study) has to be well established. For this purpose, a baseline study needs to be more integrated than ever, particularly when environmental legislation is increasingly becoming stringent and integrated. This research investigates and concludes that no clear evidence of computer models for baseline study has been found in a whole-system and integrated format, which risk assessors could readily and effectively use to underpin risk analyses holistically and yet specifically for landfill leachate. This is established on the basis of investigation of software packages that are particularly closely related to landfills. Holistic baseline study is also defined along with its implications and in the context of risk assessment of landfill leachate. The study also indicates a number of factors and features that need to be added to baseline study in order to render it more integrated thereby enhancing risk analyses for landfill leachate

Aspiration and reality: flood policy, economic damages and the appraisal process

Research to illustrate how the appraisal process, and increased flood damage potential, conflicts with the UK Government's new thinking about flood risk management. Asks questions of the Government's policy aspirations and calls for a change in investment decision making processes

Assessing the contribution of urban green spaces in green infrastructure strategy planning for urban ecosystem conditions and services

Maintaining ecosystem services is a key adaption option towards sustainable cities and adaptive societies in securing citizens’ health and wellbeing. This research investigates the contribution of using urban green space components as the basic units in green infrastructure strategy planning for urban ecosystem conditions and services. A total of 9 types of urban green spaces are selected and delineated from the high-resolution data. A combination of the quantification method of 6 common urban ecosystem services based on urban green spaces and the MAES framework in reference to literature data is used. A case study of Cheltenham, a typical urban town in England, is studied to present the new approach for local green infrastructure strategy development for urban ecosystem conditions and respective services in improving the resilience of a city in facing global climate change. Results show that changing the composition and spatial arrangement of urban green space components, synergy or tradeoff of various services can be stimulated easily. The small scale of urban green space components allows local detail planning and potential integrated planning among other urban settlements