water supply Flashcards
key strategic priorities for 3 waters?
meet watert need gfor next 50 years
adapt to future scenarios like limate change
reduced oil use
improve discharge quality
maintained into future
limit cost increase
intergrate3d approach to three water management
how many different places water sourced from in chch, how mnay wells
50 places, up to five wells, 200 mm diameter, 22 to 190 m deep
whow many pipes
1300 km of mains total of 1500 km
pipes made from>
cast iron, lined with plastic of fibrolite
key design considerations of water supply system (10)
quality capacity structural strenght fire supply service life seismic resistance corrosion resistance whole life cvost for 50 years ability to service future extensions security
what is the design basis for water supply
Customer determines quality quantity
how may litres per person, and what is it brokedn up intoq
180-250 l/day .3 shower .3 toilet .2 kitchen .2 laundry
industrial high water and low wagter use examples
high, food processing, beverages, paper mil, textiles,
low, warehouses, electrical goods
what is the maximum pressure head allowance in pipe equation
max=Hs +S + E
Hs is static pressure head
s is surge allowance
E is lowest ground level of pipe
what is surge caused from
rapid change in pressure, such as pump shutting off or valve or somthing
issues with metal pipes
lining has to be fully repaired when undergoing maintainance
electircal curent
corrosion
issues with PVC
uv degredation
scratches
must be installed correctly
permeaition of contaminants
PE issues
as with pvc, also permeation of hydro carbons
high skilled workers required
types of valves
sluice valves
air valves
scour valves
backflow prevention
two causes of backlfow
sudden drop in pipe pressure
main is connected to machinery like boiler forcing it back
