Journal of Water Resources Planning and Management

A conjuctive‐use management model is presented that can be used to develop planning and operational strategies for a river basin. In contrast to previous investigations, the conjunctive‐use model explicitly incorporates (1) The hydraulics of the surface and ground‐water systems; and (2) water‐supply, hydro‐power, and ground‐water cost and benefit objectives. Operational constraints include hydropower production limits, water‐quality constraints on the blended surface water and ground water used to meet the municipal demand, and minimum instream flow needs downstream of the water‐supply abstraction point. The model is applied to the Mad River basin in Northern California. Optimal planning policies are developed for the water resource system. The optimization model is solved using MINOS, a large‐scale, nonlinear programming algorithm. The results indicated that conjunctive‐use management is a viable tool for multiobjective water resources planning problems.

Benefit/cost ratio and net benefit are the two most commonly used criteria for evaluating the economic merit of public development projects. Due to the existence of uncertainty in cost and benefit estimations, the benefit/cost ratio and net benefit cannot be quantified with absolute certainty. In most probabilistic benefit/cost analysis the probability distributions of the benefit/cost ratio are chosen arbitrarily. The intent of this paper is to present the results from a numerical experiment in attempting to identify the appropriateness of various commonly used probability distributions in describing the random behavior of the benefit/cost ratio and net benefit of an economic development project.

In many areas throughout the United States, ground‐water supplies are contaminated by nitrates. Nitrate contamination has been a subject of concern because nitrate salts can induce infant methemoglobinemia and possibly cancer. Nitrate risk management describes the process of evaluating risk‐management strategies and selecting the best management scheme. Available nitrate risk‐management strategies can be investigated based on the acceptable level of human health risk, the reasonableness of the nitrate‐control cost, and the technical feasibility of each nitrate‐control method. However, the objectives of the risk reduction and cost are in conflict. In addition, each phase of the risk, cost, and technical‐feasibility assessment is associated with uncertainty. In this study, a multicriterion decisionmaking methodology is provided to assist decision makers in determining, with uncertain information, which of the nitrate risk‐management strategies best satisfies the considerations of health risk, cost, and technical feasibility.

A federal district court jury in Cheyenne, Wyoming, ruled that an Act‐of‐God defense could not be used when a railroad culvert backed water onto residential properties during a catastrophic “10,000‐year” rainstorm. The culvert capacity not only met but exceeded industry design standards, yet the jury concluded that the railroad was negligent for not installing a structure large enough to accommodate the “monster” storm. The 5‐ft‐diameter culvert, installed to replace a larger, deteriorating trestle, is sized by frequency‐based methods to discharge the 50‐year peak flow rate, with a nominal surcharge anticipated during the 100‐year event. It is agreed by both sides that the selected structure could have safely passed more than a 500‐year event, but is not able to discharge all the flows from the freak storm. Backwater ponded 9 ft over the top of the culvert, flooding more than 20 basements in one subdivision. The defendant is held liable for the damages and cited as negligent for not anticipating the storm and for failing to consider the risks to the homeowners. Under court order, a large structure is installed. This paper is a review of several matters debated during the trial and in subsequent analyses, presented as a case study from the writer's perspective. The writer participated as an expert witness who performed the analysis for the defense, but was called to the stand as a witness for the plaintiff. The jury verdict was in favor of the plaintiff. Implications for improvements in drainage design and expert testimony are discussed

The operation policy of Lake Shelbyville, Illinois has been modified several times in the past 20 years due to unusual weather conditions and changes in basin‐wide water resources development. A modified stochastic dynamic programming (SDP) model, which accounts for the unrepeatable agricultural and property damages and improves the accuracy of these damage estimates, is used to evaluate the performance of Lake Shelbyville. The optimal pool levels in the summer months are found to be 2–5 ft lower than the current target level of 599.7 ft. The expected damages in the model increase by 9% when a penalty function is used to force the summer pool to the current target. Moreover, it would take more than one month for Lake Shelbyville to resume the summer pool from the winter drawdown. A transition period of at least two months for lake levels between winter and summer appears warranted.