Climate change and catchment hydrology

Climate change is expected to alter catchment hydrology through changes in extremes of flooding and drought. River catchments are complex, dynamic systems and it is important to develop our understanding of how these systems are likely to respond to changes in climate. Work is ongoing in using EC-Earth simulations to further our understanding of how climate change will affect catchment hydrology and flood risk. In Ireland, the importance of this task is emphasised given the widespread socio-economic impacts of recent flood events. This chapter reviews recent Irish research concerning the hydrological impacts of climate change

Sensitivity of the performance of a conceptual rainfall-runoff model to the temporal sampling of calibration data

The effect of the time step of calibration data on the performance of a hydrological model is examined through a numerical experiment where HYMOD, a rainfall–runoff model, is calibrated with data of varying temporal resolution. A simple scaling relationship between the parameters of the model and modelling time step is derived which enables information from daily hydrological records to be used in modelling at time steps much shorter than daily. Model parameters were found to respond differently depending upon the degree of aggregation of calibration data. A loss in performance, especially in terms of the Nash–Sutcliffe measure, is evident when behavioural simulators derived with one modelling time step are used for simulation at another time step. The loss in performance is greater when parameters derived from a longer time step were used for simulating flow with a shorter time step. The application of a simple scaling relationship derived from a multi-time step model calibration significantly decreased the loss in model performance. Such an approach may offer the prospect of conducting higher temporal resolution flood frequency analysis when finer scale data for model calibration are not available or limited

Climate Change and Water Resources

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The Likely Physical Impacts of Future Climate Change on Inland Waterways and the Coastal Environment in Ireland

While increasing temperatures in Ireland are projected to occur in all seasons and time periods, it is likely that projected changes in the seasonal and spatial distribution of rain will present a much greater challenge, particularly during the summer months in the south and east of the country. Reductions in summer precipitation, leading to significant decreases in water availability and quality will result in increased competition between municipal, agricultural, and commercial interests, including tourism. Decreases in summer precipitation, together with increased evaporative losses are also likely to affect terrestrial ecosystems, particularly water dependant systems such as turloughs and fens. Changes in seasonal water levels and the occurrence of extreme high and low flow events will directly impact on river navigability, cultural heritage, and the plant and animal communities of the riparian zone. Inland waterways also provide an important resource for potable water extraction and effluent removal, in addition to providing a tourism and recreational resource. Climate change will also result in changes in sea level, wave energy and storm surges with consequent impacts on the coastal environment, particularly for coastal heritage. These impacts are likely to be further exacerbated due to ‘non-climate’ pressures arising from increasing population and development within the coastal zone. In order to determine the likely impacts of climate change on inland waterways and the coastal environment in Ireland, this chapter will present a review of recent research as it applies to impacts in these areas in Ireland

Climate Change and Water Resources

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Integration of HBIM and 3D GIS for Digital Heritage Modelling

This paper outlines a new approach for digitally recording cultural heritage sites from laser scan data or photogrammetric data. This approach involves 3D modelling stage and the integration of the 3D model into a 3D GIS for further management and analysis. The modelling stage is carried out using a new concept; Historic Building Information Modelling (HBIM). HBIM uses Building Information Modelling (BIM) software with parametric and procedural modelling techniques to automate the modelling stage. The HBIM process involves a reverse engineering solution whereby parametric objects representing architectural elements are mapped onto laser scan or photogrammetric survey data. A library of parametric architectural objects has been designed from historic manuscripts and architectural pattern books. These parametric objects were built using an embedded scripting language within the BIM software called Geometric Descriptive Language (GDL). Using this embedded scripting language, elements of procedural modelling have also been replicated to automatically combine library objects based on architectural rules and proportions. If required the position of elements can be manually refined while overlaying the automatically generated model with the original survey data. After the 3D model has been generated the next stage involves integrating the 3D model into a 3D GIS for further analysis. The international framework for 3D city modelling, CityGML has been adopted for this purpose. CityGML provides an interoperable framework for modelling 3D geometries, semantics, topology and appearance properties. CityGML enables further historical information to be added to the model and allows for efficient management and analysis of all data relating to a heritage site. The aim of this research is to bridge the gap between parametric CAD modelling and 3D GIS while using benefits from both systems to help document and analyse cultural heritage sites

Current State of the Art Historic Building Information Modelling

In an extensive review of existing literature a number of observations were made in relation to the current approaches for recording and modelling existing buildings and environments: Data collection and pre-processing techniques are becoming increasingly automated to allow for near real-time data capture and fast processing of this data for later modelling applications. Current BIM software is almost completely focused on new buildings and has very limited tools and pre-defined libraries for modelling existing and historic buildings. The development of reusable parametric library objects for existing and historic buildings supports modelling with high levels of detail while decreasing the modelling time. Mapping these parametric objects to survey data, however, is still a time-consuming task that requires further research. Promising developments have been made towards automatic object recognition and feature extraction from point clouds for as-built BIM. However, results are currently limited to simple and planar features. Further work is required for automatic accurate and reliable reconstruction of complex geometries from point cloud data. Procedural modelling can provide an automated solution for generating 3D geometries but lacks the detail and accuracy required for most as-built applications in AEC and heritage fields

Vulnerability Assessment and Adaptation Appraisal for Surface Water Resources

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