A method for quantifying water scarcity in relation to ecosystems
and human users at downstream locations in terms of water deprivation
has been developed by Pfister et al. (2009). For determining the
water deprivation, first the consumptive water use (CWU) of products,
services, and organizations must be investigated. Second, the water
stress index (WSI) of the watershed where the products have been
produced must be determined. The WSI is the ratio between the total
annual freshwater withdrawals and the hydrological availability, or
available water, in a region or watersheds. Third, water deprivation
can be calculated by multiplying the CWU of the products with the
WSI of the specific watershed where water is withdrawn for producing
products (Pfister et al., 2009). The growing of oil palm and establishing
new palmoil mills with lowwater deprivation values can minimize the
water scarcity in ecosystems and by human users at the downstream
location.