DEMAND SIDE MANAGEMENT OF WATER IN ONTARIO MUNICIPALITIES: STATUS,PROGRESS, AND OPPORTUNITIES1

ABSTRACT: Demand side management is being used increasingly by Ontario municipalities as a way to improve the efficiency of water use, defer the costs associated with constructing new water treatment works, and minimize the environmental impacts associated with supplying water. A comprehensive survey of 153 Ontario municipalities was completed in mid‐1998. These ranged in size from small rural townships (with populations as low as 500 people) to the province's largest urban center, Metropolitan Toronto, with a population of approximately 2.5 million people. The questionnaire measured the use of six broad types of demand side measures, including water pricing and metering; municipal by‐laws (ordinances) that promote water conservation; operational and maintenance measures to reduce water losses and consumption; water‐saving plumbing fixtures and devices; public participation programs that encourage water conservation; and other measures, such as water audits. Additionally, the survey collected data on implementation barriers and opportunities. Since the last comprehensive Ontario survey, conducted in 1987 by Kreutzwiser and Fea‐gan (1989), there has been an increase in the use of basic tools such as metering and pricing, plumbing fixtures, and public participation programs. Additionally, new initiatives, such as water audits and computerized monitoring equipment, are being used. However, in many areas opportunities exist to make better use of demand side measures. Unfortunately, municipal capacity to do so often is constrained by (among other factors) limited finances, lack of political will, and public resistance. Demonstration of real cost savings to consumers, and the development of specific goals and objectives for demand side management programs, are two important steps needed to overcome these challenges.     

Source-term development for a contaminant plume for use by multimedia risk assessment models

Multimedia modelers from the US Environmental Protection Agency (EPA) and US Department of Energy (DOE) are collaborating to conduct a comprehensive and quantitative benchmarking analysis of four intermedia models: MEPAS, MMSOILS, PRESTO, and RESRAD. These models represent typical analytically based tools that are used in human-risk and endangerment assessments at installations containing radioactive and hazardous contaminants. The objective is to demonstrate an approach for developing an adequate source term by simplifying an existing, real-world, ⁹⁰Sr plume at DOE's Hanford installation in Richland, WA, for use in a multimedia benchmarking exercise between MEPAS, MMSOILS, PRESTO, and RESRAD. Source characteristics and a release mechanism are developed and described; also described is a typical process and procedure that an analyst would follow in developing a source term for using this class of analytical tool in a preliminary assessment.     

Horizontal diffusion by submeso motions in the stable boundary layer

Four networks of wind data are used to construct the first systematic estimates of the horizontal diffusivity from observations of submeso motions on scales often unresolved in numerical models. Currently, the horizontal diffusivity in numerical models is specified mainly for numerical reasons without observational support. The data analysis in this study emphasizes the stable boundary layer although results are briefly presented for the unstable boundary layer. The horizontal diffusivity is estimated from the horizontal gradient and the observed flux. Horizontal gradients of scalars are generally difficult to directly estimate from observations with sufficient accuracy for much of the data. As an alternative, simulated particles with conservative properties are introduced into the observed wind field in order to estimate the horizontal diffusivity for submeso motions. The sensitivity of the horizontal diffusivity to details of the method is examined. The horizontal diffusivity increases with the range of time and space scales that are included in the evaluation. The horizontal diffusivity is much larger with significant topography and may increase with wind speed, depending on the site location. The coarse station spacing or the small domain size is found to be a major limitation to the analysis.     

Toxic and nutrient element concentrations in soft tissues of zebra and quagga mussels from Lakes Erie and Ontario

Zebra and quagga mussels were collected from Lakes Erie and Ontario in 1997 and the soft mussel tissues were analyzed for Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Se, Sr, V and Zn. No consistent relationships were apparent when comparing element concentrations in soft mussel tissues and mussel type, size range or sampling location. Literature dealing with the absorption of metals by both mussel types is reviewed.