A METHODOLOGY TO DETERMINE OPTIMAL TRANSMISSIVITY MEASUREMENT LOCATIONS IN GROUNDWATER QUALITY MANAGEMENT MODELS WITH SCARCE FIELD INFORMATION

A new criterion to determine transmissivity measurement location for g roundwater quality management models is proposed. The transmissivity i s represented as a random held with known mean and covariance function , conditioned to existing measurements values. The criterion is the mi nimization of the coefficient of variation of the optimal remediation cost distribution. This distribution is computed numerically by means of Monte Carlo simulations in which each optimal remediation cost is e valuated by solving a deterministic management problem, where the tran smissivity is a single realization of the random field. The coefficien t of variation is equivalent to the relative error in the prediction o f the optimal cost and is shown to be invariant with respect to the ac tual (unknown) measurement value according to some limiting conditions . In the more general case the coefficient of variation of the optimal cost is less sensitive than the expected optimal cast to the actual m easurement value. The proposed criterion becomes a useful tool to dete rmine the ''best'' transmissivity measurement location when only few m easurements have been performed.