Optimising storm-water drainage networks
This thesis examines ways in which the design of storm water
drainage networks can be optimised and proposes, develops and tests
some such methods.
The introduction is followed by a r~su~ of current design
practice and an examination of previous work on the drainage optimisation
problem. Methods of estimating the construction cost of a
drainage ne:twork are detailed and fwctions proposed for modelling
The optimisation problem may logically be split into two areas,
namely optimising fixed plan networks and optimising variable plan
networks. The former involves the simultaneous selection of gradients
and diameters for a network of pipes fixed in plan. A new Dynamic
Programming model is proposed for this, having several advantages over
previously published methods.
The main area of innovation is, however, in optimising variable
plan networks. The general plan optimisation problem is seen to be
far too complex for solution. However~ taking the special case of
road drainag~ networks» two possible modes of optimisation are defined.
These are, firstly, the positioning of an unknown number of manholes
along a drain running between two fixed manholes, and secondly, the
positioning of an unknown number of cross-drains along a road carriageway.
Both modes include the simultaneous choice of pipe gradients and
Models for these modes are proposed, with practical computer
programs being developed and tested. Both models use a novel form of
Dynamic Programming conceived and developed during this research.
The thesis ends with a brief outline of a Dynamic Programming
solution to a rather different variable plan problem, followed by
suggestions of areas for further study and conclusions of both a
specific and a general nature.