Economic Aspects of Decision Making in Reliability Assessment of Water Distribution Networks - Pattern Recognition for Reliability Assessment of Water Distribution Networks - page 216

Table 8.4 Network scenarios for reliability analysis

VARIABLES LABEL OPTIONS TOTAL

Supplying Scheme A Direct Pumping (Net A) 2 scenarios

B Pumping & balancing tank (Net B)

Topography pattern F Flat 10 scenarios

U Slope up

D Slope down

H Hill

V Valley

Altitude range L Low altitude range (10 - 20m) 30 scenarios

M Medium altitude range (10- 30m)

H High altitude range (10 - 40m)

Investment/operation
combinations

HH High investment - high operation 120 scenarios

HL High investment - low operation

LH Low investment - high operation

LL Low investment - low operation

Design scenarios 21 combination of network resistance

and pumping capacity

2520 scenarios

Table 8.5 Network scenarios for reliability analysis

Investment
cost

Operation
cost

Annual
interest

Loan
repayment

Annual
inflation

Energy cost
(US$/kWh)

Label

HH High High 12% 10 years 10% 0.45

HL High Low 12% 25 years 10% 0.05

LH Low High 4% 10 years 4% 0.45

LL Low Low 4% 25years 4% 0.05

The first costs have been calculated applying uniform equation aX n where X stands for pipe
diameter (in mm), storage volume (in m 3 ) and maximum installed capacity of pumping
station (in l/s), respectively. Corresponding factors a and n have been applied as shown in
Table 8.6.

Table 8.6 Factors used for the first cost

Factor D (mm) V (m 3 ) Q (l/s)

A 1 222 22,222

N 1 1 0.8

All the simulations have been run for single steady state, and at constant demand.
Consequently, the volume of the balancing tank in B of 2124 m 3 has been kept constant all
the time (also in the cost calculations). Finally, the same percentage of the investment costs
has been adopted for annual costs of operation and maintenance, as suggested above: 0.5%
for pipes, 0.8% for storage and 2.0% for pumping station. To enable efficient work while