QUANTITATIVE METHODS FOR PRELIMINARY DESIGN OF WATER QUALITY SURVEILLANCE SYSTEMS¹

Abstract

To assure attainment and maintenance of desired water quality levels in our rivers and streams, systematic monitoring must be performed. A preliminary phase of the design of water quality surveillance systems is the specification of sampling frequencies and station locations throughout the basin; that is, the development of an adequate space/time sampling plan. The purpose of this paper is to present some quantitative methods which have been developed to identify candidate sets of sampling frequencies and station locations, and to establish priorities for implementing the different frequencies and locations. These methods are useful in the cost/effectiveness trade‐off analyses in surveillance system design, and are based on the surveillance system objective of pollution abatement in which it is desired to detect violations in state‐federal water quality standards. A spatial priority measure is developed which is dependent both on the water quality profile in the stream and on the information obtained from monitoring stations located in other reaches. Also, a temporal sampling priority rating is presented which is a measure of the effectiveness of the surveillance system with respect to its ability to detect the violations in the standards. To illustrate the quantitative methods, the procedures are applied to the Wabash River Basin.

PROBABILISTIC METHODS IN STREAM QUALITY MANAGEMENT1

“…Ditoro and O'Connor (1968) considered the influence of uncertainty in the velocity distribution on the downstream distribution of BOD and DO. More recently, Chamberlain, et al (1974) have made use of first order analysis discussed below to determine the first two moments of the DO distribution; as in the earlier work they assume deterministic values for the rate constants. The first two moments of the distribution so approximated (mean and variance) are used to specify a normal distribution.…”

Landfill Gas Effects on Groundwater Samples at a Municipal Solid Waste Facility

“…Significant effort has been expended to develop more costeffective approaches to monitoring, including efforts to identify parameters that may be used as valid early indicators of leachate effects on groundwater samples (Chamberlain et al 1 ; Gibbons2; Rajagopal and Williams 3 ; Plumb 4 ; Plumb and Pitchford 5 ). In several publications, volatile organic compounds (VOCs) have been suggested as valuable indicators of leachate effects (Plumb 4 ; Plumb and Pitchford 5 ).…”

Stochastic dynamics of BOD in a stream with random inputs

“…0309 This method has been widely used for river pollution problems [12,38,47]; a detailed description of this approach in water quality models is given by Beck and van Straten [4]. It is formally simple and gives an approximation which is as better as the variance is great compared to the mean [9]; it can also prove to be erroneous for non-linear equations and its drawbacks for water quality applications have also been underlined [17,31].…”

“…All the complexities of the process were condensed into a single value of the decay coefficient, the initial conditions and the BOD inputs were assumed deterministic and a single analytical solution was therefore easily obtained using the deterministic differential model. Starting from the 1970s, researchers began to model the randomness that exists in the dynamics using probabilistic approaches [9,12,17,26,28,29,36]. Three different approaches have been developed: first-order error analysis, Monte-Carlo methods, and stochastic differential equations.…”