Resource information
There is an increasing demand for water resources in the Canterbury region. Theimpact of this demand has lead to unacceptable minimum river flows, which hasresulted in adverse affects to river ecology. In an effort to resolve this problem waterstorage projects have gained considerable attention. However, in order to consider allvalues of the impact of water storage projects, a systematic way of implementing anecosystem services approach is developed. This ecosystem services approachcoupled with various appropriate analytical methods are developed for the purposesof evaluating the cost-effectiveness of water storage projects and the sustainability ofriver systems impacted by water storage projects. For the purposes of evaluating thecost-effectiveness of water storage projects it is argued that cost utility analysisshould be applied through an ecosystem services index, which is constructed fromthe aggregation of normalized indicators that represent each ecosystem service andpreferential weights for each ecosystem service. The evaluation of sustainability isconsidered both according to its weak and strong definitions. Weak sustainability isevaluated by a non-declining ecosystem services index over time. Strongsustainability is evaluated by the elicitation of threshold levels or safe minimumstandards where an ecosystem service, as represented by an indicator, should notpass below. These analytical methods developed are subsequently applied to theOpihi River, which is a river system located in Canterbury that has beenhydrologically modified and impounded by the Opuha Dam scheme. The applicationof the analytical methods to the Opihi River provides a few preliminary results.Further data collection is required to fully determine the cost-effectiveness of theOpuha Dam and the sustainability of the Opihi River impacted by the dam scheme.
