Abstract:
Water distribution systems operate under constantly varying conditions that display both deterministic and probabilistic behaviour. Design guidelines, on the other hand, typically specify reservoir storage capacity in terms of deterministic parameters only. A method is presented for analysing the reliability of municipal storage reservoirs based on stochastic models of water demand, pipe failures and fire events. The method was applied to the Yeoville water supply system in Johannesburg and showed that its reservoir complex has a good level of reliability even though it is significantly smaller than required by the South African design guidelines. The analysis considered a number of layout changes to the supply network which could have significant impacts on the reservoir reliability. In conclusion, it is shown that the sporadic demands of fire flow do not significantly affect the reliability of the Yeoville reservoir complex.