The benefit function also incorporates parameters that affect all users, such as input and output prices and weather.7 For example, in a dry year, it is expected that the benefit from applying any amount of water to a crop will be larger than in a wet year. First-best optimisation would require explicit valuation of all possible environmental services associated with the groundwater resource, both now and in the future. Instead, society decides on the level of hydrologic services that is desirable and the economic problem is to achieve that level using a solution that maximises benefits to water users.