Abstract:
In recent years, the increasing awareness of scarcity of water resources, indications of
likely climate variability, and the increasing pressure to use available fresh water
resources more efficiently have together reinforced the need to look at infrastructure
solutions with due regard to environmental considerations and social impacts, present
and future. There is a vital need to apply an integrated approach to catchment
management to implement sustainable solutions to resolve issues such as water supply
and sewerage, drainage and river flooding. Many potentials solutions are available to
control water demand and manage flood problems. Greywater recycling and rainwater
harvesting are novel technologies. However, their catchment scale impacts on
hydraulic and hydrological flows are poorly understood. The research aim is to
identify the hydrologic and hydraulic impacts of scaling up such technologies at
catchment scale. For this particular study, a computer simulation model will be used
to evaluate how increasing urbanisation, climate change and the implementation of
greywater recycling and rainwater harvesting may alter the water balance within a
representative catchment. To achieve these aims data from the Carrickmines
catchment in Ireland have been collected; a simulation model has been adapted to
carry out the study, the model has been calibrated and validated, results have been
analysed, and finally, a sensitivity analysis has been carried out. The results show that
rainwater harvesting systems are comparatively more effective than greywater
recycling techniques in reducing flood frequency and intensity. Under five year return
period rainfall events, the implementation of rainwater harvesting at any scale and
number of units is a useful technique to control river flow and floods. However, the
study also shows that under extreme conditions the efficiency of rainwater harvesting
systems decreases. The study concludes that implementing the two technologies
within a single catchment is not a solution to several forms of hydrological problem.
The study shows that implementing rainwater harvesting or re-use technologies are a
very useful way to protect local freshwater reserves and therefore conserve our
environment.
