Environmental Engineering Reference
In-Depth Information
10.1
RESEARCH SUMMARY
The research presented in this manuscript consists of theoretical part dealing with definition
of network measures describing the node connectivity, the hydraulic performance and
eventually the resilience, and the practical part comprising the development of decision
support tool for reliability-based network design.
The pressure-driven demand algorithm presented in Chapter 3: 'Emitter Based Algorithm for
Pressure-Driven Demand Calculations of Water Distribution Networks ', uses EPANET
emitter coefficients that become active in all the nodes where the pressure drops below the set
threshold value. The options to disconnect the pipes or set the demand at zero when the node
pressure becomes negative, resulting from extreme topography, have also been considered.
The threshold pressure is used to calculate the value of emitter coefficient from the baseline
demand and fixed exponent.
The network generation tool presented in Chapter 4: ' Spatial Network Generation Tool for
Performance Analysis of Water Distribution Networks ' has been developed based on the
principles of graph theory. It uses the information from the set of junctions prepared in the
EPANET input file and generates the selected number of networks either by random- or non-
random generation. The generated networks receive the properties that are assigned in
random or controlled way (fixed values, or calculated from coordinates, for pipe lengths, or
in the process of GA-optimisation, for pipe diameters).
The research presented in Chapter 5: 'Hydraulic Reliability Diagram and Network Buffer
Index as Indicators of Water Distribution Network Reliability' presents an alternative way of
expressing the reliability index being derived from a diagram named the hydraulic reliability
diagram (HRD), showing the correlation between the pipe flows under the regular supply
conditions and the loss of demand caused by their failure. The reliability index derived from
the position of the dots on the graph, adding proportional weighting to the pipes carrying
more flow under normal condition, has been proposed as the network buffer index (NBI),
which takes into consideration only the consequences of the failure and not the chance that it
would happen.
The research from Chapter 6: 'Impacts of Node Connectivity on Reliability of Water
Distribution Networks' analyses the impacts of node connectivity on network resilience. Two
approaches have been compared to evaluate this connectivity: one which does it in relative
terms and in simplified way, by taking into consideration the connectivity of the two most
dominant node categories in three different ways (eventually comparing three different
connectivity indices), and the other which considers the connectivity measures based on
graph theory used in the NodeXL spreadsheet template available in public domain.
The research presented in Chapter 7: 'Diagnostics of Regular Hydraulic Performance of
Water Distribution Networks and its Relation to the Network Reliability' assesses the
potential of water distribution networks to sustain a certain level of failure based on the
survey of their hydraulic parameters under regular supply conditions. Three different
reliability measures have been analysed: the network power index (NPI), the pressure buffer
index (PBI), and the network residence time (NRT). Furthermore, several statistical analyses
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