Modified streamflow is projected to affect the amount and variability of inflow to urban storage reservoirs , which may ex- acerbate existing challenges to urban reservoir capacity, such as sed- imentation and poor water quality . For example, in Melbourne , a combination of stochastic hydro-climatological modelling, rainfall- runoff modelling and climate model data projects a mean precipitation shift over catchments by -2% at 1.5°C and -3.3% at 2ºC, relative to 1961-1990. Considering an annual water demand of 0.75 of the mean yearly inflow, the median water supply shortage risk was calculated to be 0.6% and 2.9% at 1.5℃ and 2℃ warming levels, respectively. At the higher demand level of 0.85 of the mean annual inflow, the median water shortage risk is higher, between 9.6% and 20.4% at 1.5°C and 2ºC warming, respectively, without supply augmentation desalination .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report