11.6.4 Cost of Providing Resilience
The different forms of resilience explained above have a cost. For example,
(1) During the 1999–2000 drought, the cost of providing water tanker service and
other facilities, amounted to some Rs. 50 million (2.5 million Euros, at
that time).
(2) The pipe linking Mare Longue reservoir to La Marie filters cost Rs. 50 million
(1.25 million Euros, at the 2018 exchange rate), for an addition of 20,000 m
3 /d,
which is no longer available for hydropower and irrigation.
(3) The pipe connecting Midlands reservoir and Piton du Milieu reservoir is estimated at a cost of Rs. 400 million (10 million Euros, at the 2015 exchange rate),
for an addition of 20,000 m
3 /d.
These figures may be compared to an average selling price of water of Rs. 9/m
3 ,
for a total annual sold volume of about 90 Mm
3 . A cost benefit analysis could be
carried out to assess the feasibility of adding such resilience. Interestingly, when it
comes to water, is there an option of doing without (resilience or water)?
Table 11.17 Adding resilience to the water supply network of Mauritius
Robustness Redundancy Reliability Resourcefulness
Response
after
event
Surface water/ground
water conjunctive use
♦
♦
♦
♦
Double borehole
♦
♦
♦
Standby generator
♦
♦
♦
System
interconnection
♦
♦
♦
♦
River (surface) pump
♦
♦
Water rights use during drought
♦
♦
Tanker service during
drought
♦
♦
New impounding
reservoirs
♦
♦
♦
New service
reservoirs
♦
♦
♦
Local/domestic storage tanks
♦
♦
♦
New treatment plants ♦
♦
♦
11.6 Case Study: Resilience in a Water Supply Network
329