4 - Water Supply Flashcards
How many litres of water does the average person use per day?
150
From the water supply requirements, what should water quality not be compromised in?
The distribution pipes
What should water sources be capable of supplying enough water during?
Firefighting
How far from sewer pipes be laid from distribution pipes?
At least 1m
What should water losses through leakage be kept to?
A minimum
What do pipes under pressure help prevent?
Contaminant ingress
What does maintaining a minimum velocity help prevent?
The build up of microorganisms
What is the trunk main?
The pipe used for the transport of potable water from the treatment plant to the distribution area.
What do trunk mains have diameters between?
100mm and a few meters, for example the London Ring Main
What are secondary mains?
The pipes that form the basic skeleton of the distribution system
What do secondary mains link?
Main components, such as sources of water, reservoirs and pumping stations.
What do distribution mains do?
Convey water from the secondary mains towards various consumers, and are laid under or alongside road and streets.
What do service pipes do?
Bring water directly to the consumers
What are the 4 types of water supply network configurations?
Serial, branched, looped, combined.
What is a serial network configuration?
A cheap connection, with many dead eneds, stagnation in water pipes can occur.
What is a branched supply water network connection?
A combination of serial networks - low reliability and stagnant water.
What is a looped water supply network system?
Where water can flow in one or more direction, resulting in less stagnation - during maintenance, the area concerned will still recieve a water supply
What is a combined water supply network configuration?
Most common - looped structure from central part with a supply to outskirts provided through a number of serial branches.
In a city such as Nottingham, water is removed from the distribution system at a very large number of points, name some of these points:
Houses, fire hydrants, commercial and government buildings.
A distribution system can be considered to consist of a network of nodes and links, what are these?
Nodes = points of concentrated flow withdrawal or supply
Links = pipes connecting to the nodes
What is the Hardy-Cross method?
A simple iterative method that is used in the analysis of flows in water supply method with loops.
What is the first step in the Hardy-Cross method?
Assume the flow rates, Q in each pipe, respecting the continuity equation in each node
qA - qAB +qDA = 0
What do water companies use for the design of water supply systems?
Software
What do water towers do?
Deliver potable drinking water.
Supports a water tank at a suffien height to provide an emergency supply of water for fire protection
