Modelling an Intermittent Water Supply
Modelling an Intermittent Water Supply
复制标题
间歇供水建模
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
K. Sridharan
中科院分区：
文献类型：
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作者：
N. Sashikumar;M. Mohankumar;K. Sridharan
In an Urban water supply scheme the normal mode of supply in a developing country such as India, is of intermittent nature with restricted supply hours to each area. The supply to different areas takes place in rotation. The operating conditions in such a system can be very varied depending on the zonation pattern for rotational supply and duration of supply for each zone. Normally available models of distribution system such as EPANET are mainly applicable for continuous supply. While this as well as other models may also contain a provision for considering pressure dependent consumption, in an intermittent supply system, the network operation may shift from pressure dependent consumption to demand controlled consumption, both in space and time. There are several other modelling issues in intermittent water supply such as the effect of initial filling of pipes in several segments when the supply is started. Field experiments have shown, that it may take even one to two hours for air to be fully vented out from a distribution system, after which the normal modelling conditions will apply. Observations indicate that the Hazen-Williams C value in such a system may be low in the initial period of supply (associated with presence of air packets) and reaches the true value after a period. The use of distribution network models for evaluation of different upgradation or rehabilitation plans for the network with an intermittent supply is a challenging task. The alternate emptying and refilling of large segments of pipelines will make it very difficult to apply conventional water quality models in a network. The risk of contamination from external source also increases in an intermittent water supply system due to repeated emptying and filling of pipeline. The paper will focus on some of the issues related to intermittent water supply from practical and modelling considerations.
