Since it is relatively easy to quantify, this report does not discuss in details how to set full supply cost. Rather, the focus is on two other types of costs that are more difficult to estimate, and may be less obvious to both the general public and the users of the water resource. Figure 3.3 describes a situation where fees and tariffs do not cover the full supply cost of dam or multi-regional water. For example, too much groundwater abstraction can cause saline intrusion in coastal aquifers while the ecosystem of rivers and other surface waters may be degraded when river flows become too low.