Impacts of Climate Change on the Hydrological Cycle

[This is a guest post written by one of the department’s 3rd Yr Single Hons / Major students]

Peter Gleick, a well-known and leading expert on climate and water related issues, shows the urgent need for preparation and adaptation in society to future flood, as a result of climate change, in this short video below.

The current condition of our climate can be best described as non-stationary, with global average temperatures projected to increase in the coming decades, encouraging more devastating hydrological hazards to take place. This has been experienced all around the globe, and it is expected to occur more frequently in the near future.The most catastrophic event occurred in 1991 in Bangladesh, which gave rise to a death toll totalling 140,000 people. In 2000, the river Elbe in Europe was added as the most cost expensive disaster in recent decades, again driven by variations in the climate system.

We cannot think that Ireland is exempt from these effects of climate change on its hydrological cycle, because this is not the case. In fact, it has been shown by various experts, including Dr Conor Murphy and Dr Ro Charlton at NUI Maynooth, that future flood events in Ireland will mirror those of the rest of the globe as a whole. There have been studies of the effects of climate change on numerous catchments in the country including the rivers Boyne, Barrow, Feale and Blackwater, in which significant changes in river flow are expected to occur. The magnitude of flow in these catchments, are believed to increase by up to 56%, in association with a 50 year return period. However, there is no clear understanding of this scenario in many of the river catchments in Donegal. Therefore, the research question I will attempt to answer in this dissertation is: ‘How will the vulnerability of the town Ramelton, to future flood in the Leanann Catchment,be altered as a result of climate change?’

In an attempt to answer this, I will use the HYSIM hydrological model to simulate current river flows and future climatic scenarios, as a means of investigating the occurrence of future flood. The main steps involved in the application of this model will be Calibration (training the model to represent local catchment hydrology), Validation (the estimation of confidence in model simulations), the use of climate scenarios (through which the validated model will be run), and analysis(changes in flood occurrence will be assessed for the future relative to recent experience). Input data for the HYSIM model will derive from the OPW website and Met Eireann, while climate change scenarios will be obtained from ICARUS at NUI Maynooth. I will also exercise a degree of fieldwork. This will involve observing and taking pictures of the Leanann catchment and the town of Ramelton, in order to achieve a first person perspective of receptors that stand vulnerable to future flood.

Ultimately, the main goal of my thesis is to increase the knowledge of climate change effects on catchments in Co. Donegal, thus providing the opportunity for preparedness and adaptation, with a case study of the Leanann catchment.

Anthony Friel

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