AN APPLICATION OF INVESTMENT TIMING ANALYSIS: DUAL WATER SYSTEMS1

ABSTRACT: A general methodology to study the economics of dual water systems (defined here as a separate distribution system for untreated low quality local surface Water for outdoor municipal water supply) is summarized and the application of the method to a rapidly growing city is presented. In the first step, a cost-benefit criterion for evaluating dual systems is developed. The criterion is then extended to a dynamic case where the population to be served increases with time and where the dual system is allowed to expand. The optimal investment time to introduce the dual water supply project is obtained by maximizing social welfare. The model is applied to the city of West Jordan, Utah, where a dual system is currently being proposed. Model results indicate that for the city as a whole dual supply is not economically feasible. However, when the model is applied to a part of the city, it is found feasible and the optimal time to initiate the project would be in the year 1989.     

The relationship between job experiences and psychological distress: A structural equation approach

Using structural equations, we estimated the relationship between employees' experiences of seven job conditions, that have been identified as potential job stressors, and psychological distress in a random sample of 504 full-time employed men and women in dual-earner couples. The seven job conditions were: skill discretion, decision authority, schedule control, job demands, pay adequacy, job security, and relations with supervisor. We found that two job conditions — skill discretion and job demands — were related to psychological distress, whereas five other conditions were not. These findings lend partial support to Karasek's job demand — job control model. In our analysis, skill discretion, one of the two components of job control (referred to jointly as decision latitude) was related to distress, however, decision authority, the second component, was not. A third aspect of control, schedule control, was also unrelated to distress. For full-time employed women and men in dual-earner couples, the additive effects of feeling concerned about having to do dull, monotonous work and having to work under pressure of time and conflicting demands were associated with psychological distress. Finally, the magnitude of the relationships between these job experiences and psychological distress did not differ between men and women.     

Mercury cleanup: The commercial application of a new mercury removal/recovery technology

Efficient, economical treatment of mercury-contaminated soils and industrial wastes requires a treatment process that reduces mercury content to near background levels (<1 ppm) and recovers the removed mercury in pure recyclable form without producing liquid, solid, or gaseous secondary wastes. This article reviews the results achieved using a medium-temperature thermal desorption process developed and commercialized by Mercury Recovery Services, Inc. (MRS) that has successfully achieved these goals.     

Large-scale constructed wetlands for nutrient removal from stormwater runoff: An everglades restoration project

The South Florida Water Management District (SFWMD) constructed a wetland south of Lake Okeechobee to begin the process of removing nutrients (especially phosphorus) from agricultural stormwater runoff entering the Everglades. The project, called the Everglades Nutrient Removal (ENR) project, is a prototype for larger, similarly constructed wetlands that the SFWMD will build as part of the Everglades restoration program. This innovative project is believed to be one of the largest agricultural stormwater cleanup projects in the United States, if not in the world. This publication describes the ENR project's design, construction, and proposed operation, as well as the proposed research program to be implemented over the next few years.     

Preparing for ISO 14000: An assessment guide

With ISO 14000 expected to roll out in 1996, have you begun to evaluate how well your current environmental management policy, programs, procedures, and objectives conform to published national and evolving global Environmental Management System (EMS) standards?. The ISO expects to adopt a final standard by mid-1996 which specifies requirements for an EMS (e.g., ISO 14001). In addition, national EMS standards have already been developed and published by organizations such as The British Standards Institute and, in the United States, NSF International, for example, BS 7750 and NSF 110–1995, respectively. This article shows how managers can begin assessing their operations to prepare for these new standards and improve overall environmental performance.     

WATER MARKETS AND DECENTRALIZED WATER RESOURCES MANAGEMENT: INTERNATIONAL PROBLEMS AND OPPORTUNITIES1

ABSTRACT: Because of its importance and the perceived inability of private sector sources to meet water demands, many countries have depended on the public sector to provide water services for their populations. Yet this has resulted in many inefficient public water projects and in inadequate supplies of good quality and reliable water. Decentralization of water management, including the use of water markets, cannot solve all of these water problems, but it can improve the efficiency of water allocation. When given adequate responsibility and authority, water user associations have effectively taken over water management activities at a savings to tax payers. Moreover, water markets add the potential benefit of improving water efficiency within a sector as well as providing a mechanism for reallocating water among sectors. The key question involves developing innovative mechanisms for reducing the transaction costs of organizing water users and of making water trades. Water rights need to be established which are recorded, tradable, enforceable, and separate from land if markets are to operate effectively. Also, institutions are needed that effectively resolve conflicts over water rights, including third party impacts and water quality concerns.     

Environmental management in Mainland China

Summary The author was a consultant, assigned from the United Nations Development Programme (UNDP), to provide technical assistance to China's environmental pollution research and control. His assignment in China from September 1 through October 8, 1983 was filled with visits and meetings at key research institutes, universities, and regulatory agencies in the cities of Beijing (Peiking), Shanghai, Hangchow, Zhuji and Zhiaxing (Fig. 1). Trips to famous historical sites and scenic points in and around those cities were squeezed in between the heavily scheduled meetings. Dr Shen was born and educated in China through college. This is a report of his first trip back to his homeland since he left 35 years ago. His ability to communicate with the Chinese professionals and social strata in their native tongue provided him with a greater advantage in understanding the current status of China's environmental sciences and technology in preventing air, water, and land pollution. His contribution lies not only in the technical transfer of environmental sciences and engineering, but also in strengthening the ties of cooperation and communication between American and Chinese professionals. Dr Shen is a senior research scientist with the New York State Department of Environmental Conservation and an adjunct faculty member of the Division of Environmental Sciences, Columbia University.     

Effects of increased wood energy consumption on carbon storage in forests of the United States

Large but feasible increases that have been projected for the production of wood energy in the United States can be expected to significantly alter the current carbon storage patterns in US forest vegetation. The 1976 net wood increment left after forest cutting equals about 136 × 10⁶ tons of carbon/year, with about 60% of the increment found in merchantable trees, and the remainder in nonmerchantable components.Achieving 5–10 quads of wood energy beyond 1976 levels by the year 2010 can significantly change current carbon storage patterns with the magnitude of change dependent on the extent of residue harvest to meet energy goals, and the rate of future forest growth. Complete loss of the apparent net wood increment is a possible outcome.Although the future growth and harvest situation cannot be known now, a range of possible scenarios suggests that US forests in the year 2010 will store much less carbon than today, thus significantly changing their role in the global carbon cycle.     

Recreational impacts on Colorado River beaches in Glen Canyon,Arizona

Recreational impact was measured on eight beaches in Glen Canyon National Recreation Area and 15 beaches in Grand Canyon National Park using permanently located transects and plots. Recreational impact indices included densities of human trash and charcoal and a measure of sand discoloration due to charcoal. Significant increases in the indices occurred on several Glen Canyon beaches over a seven-month period. Sand discoloration became significantly higher over all Glen Canyon beaches during the same time period. All indices were significantly higher in Glen Canyon than on similar Grand Canyon beaches. These differences are probably due to differences in: (a) level of impacts tolerated by the respective management regimes and, (b) in the number of user days among the two National Park Service administrative units. Management alternatives are presented for reversing the present trends of recreational impact on Glen Canyon beaches.     

AN EVALUATION OF ALTERNATIVE POLICIES FOR CONTROLLING AGRICULTURAL NONPOINT SOURCE POLLUTION1

An economic analysis of nonpoint source pollution management was conducted for the Nansemond River and Chuckatuck Creek watersheds in Southeast Virginia. The potential effects of alternative public policies on farm income, land use, and pollution loadings were investigated. Regulatory programs could have quite different impacts depending on which pollutant is targeted. Cost-share rates greater than 50 percent would have little additional effect on pollution from crop enterprises, but would reduce pollution from livestock