Journal of Water Resources Planning and Management

Game-theoretic models are developed to study systematically self-monitoring and self-reporting requirements for industrial and other enterprises to demonstrate compliance with environmental regulations. Two specific systems are modeled and analyzed in detail. The first self-reporting system includes strict liability, whereby an operator is liable for injurious discharges but can use “due diligence” as a defense if it can demonstrate that reasonable care was taken to prevent discharges in violation of environmental standards. The second model represents an absolute liability system, in which the operator is solely responsible for violations, no matter how they were caused. Nash equilibrium analyses of these two models demonstrate that in neither strict nor absolute liability can the agency induce truthful reporting by an operator who does not provide due care. Despite inducing maximum care by the operator, absolute liability discourages that operator from reporting truthfully to the agency. On the other hand, a strict liability system cannot bring about the maximum level of care by the operator. While strict liability can prevent a hard-working operator from being punished due to chance violation, it also creates incentives for the operator to shirk and thus be less than fully diligent.

A number of computer packages have been developed for modeling chlorine decay in water distribution networks. However, there is uncertainty as to the kinetic model that they should use for the decay mechanism. This paper explores the performance of six different kinetic models for the decay of free chlorine in over 200 bulk water samples from a number of different sources. The paper also presents the results of surveying the longitudinal decay profile of free chlorine in two in situ pipe stretches. It concludes that, for network modeling purposes, it is generally reasonable to assume first-order kinetics for bulk and overall decay.

The U.S. Safe Drinking Water Act and its amendments impose restrictive rules for filtration of surface water and maximum contaminant levels for total trihalomethanes (THMs) in distribution systems. Extension of these regulations can potentially address the possibility of limiting each individual THM compound since the health risks associated with these compounds are not all alike. Current models of THMs are predicated on empirical reaction kinetic equations derived from linear and nonlinear multiregression analysis. This paper applies nonlinear optimization to model the kinetics of THM species under representative extreme conditions. The proposed approach combines site-specific trends with stoichiometric expressions based on average representative bromine content factors. The model was tested and validated using data from finished (desalinated) water collected in the United Arab Emirates. Reasonable agreements between model-predicted and measured values of different species were consistently obtained, indicating the applicability of the approach with a full dynamic water-quality transport model. This model can lead to improved management of water quality and assist utilities in attempting to optimize chlorine disinfection practices in water distribution systems.

Ground-water management is posed as the maximization of the expected value of net revenue accruing from the sale of ground water, subject to hydrogeologic, climatic, and environmental conditions. The market price of ground water, the cost of ground-water extraction, and the discount rate are economic factors included in the development of long-term aquifer management policies. Closed-forms solutions were derived for the optimization problem, and the sensitivity of solutions to the market price of ground water, the cost of ground-water extraction, climate conditions (wet or dry), and the initial hydraulic heads was determined. The optimization method was applied to a coastal aquifer and long-term management policies were obtained under a variety of climatic, economic, and hydraulic scenarios.