THE ROLE OF MINIMUM VARIANCE THEORY IN DEFINING THE REGIME CHARACTERISTICS OF THE LOWER NAMOI-GWYDIR DRAINAGE BASIN1

ABSTRACT: While minimum variance theory appears to offer an explanation for the hydraulic behaviour and regularity among channel systems it is not entirely successful in predicting the regime of a channel system. In the case of the Namoi-Gwydir river system the hydraulic variables velocity, depth, width, slope, friction, and shear appear to govern the behaviour and, hence regime of the channels. The significance of sediment load in determining regime could not be assessed.     

OPTIMAL OPERATION OF SHELBYVILLE AND CARLYLE LAKES1

ABSTRACT: Dams were built by the U. S. Army Corps of Engineers on the Kaskaskia River at Shelbyville and Carlyle in Illinois, in 1969 and 1967, respectively. The operation of the Shelbyville and Carlyle Lakes has changed over the years because of considerably lower bankfull channel capacities downstream of the dams than were adopted in the project designs. This study was conducted to review the present operation policy. Intent was to derive a policy for maximizing the overall benefits (or minimizing the overall damages) and to compare these benefits or damages with those with the present policy. The operating rules were optimized through a simulation model which was structured considering the physical nature of the system and the desirable operation in the best interest of various beneficial uses. The expected annual value of overall benefits from recreation and agriculture is shown to increase by $0.2 million with the optimal policy. With the optimal operation, the overall damages are reduced by 76 percent on the average over the 24 years of flow record at Shelbyville and Carlyle.     

ADVANTAGES AND DISADVANTAGES OF REGIONAL SEWERAGE SYSTEMS1

ABSTRACT: A few years ago, many water quality administrators were convinced that large regional sewerage systems, consisting of one large treatment plant and long trunk sewers extending out to various communities, represented the only efficient and economical means of assuring water quality control. In communities favoring rapid development, the provision of sewer service and encouragement of development of new centers along the trunk sewers offered an additional advantage. More recently quite different points of view are arising in certain areas. In parts of New Jersey strong environmental and community resistance has arisen to proposed central plant-trunk sewer systems. The facilitation of new development along the trunk sewers is viewed as a menace by townships not wanting intensive development of these areas. The diversion of effluent flows to trunk sewers rather than septic tanks would dry up the streams which water quality programs are supposed to protect. Both sides to the controversy have mobilized engineering, environmental, economic, and legal expertise and some critical policy issues have developed. Reconsideration of regional sewerage management and particularly trunk sewer policy is required. The decision as to extent of sewerage service areas involves complex and sensitive planning issues. Because of potential conflicts of interest, such decisions should not be left to staffs of sewerage authorities and their design engineers.     

农牧交错地区沙漠化防治的系统诊断

农牧交错区是我国沙漠化土地分布和危害的主要地区,是我国沙漠化防治的重点区域。本文利用层次分析法对该区沙漠化防治进行了系统分析,提出了沙漠化防治措施及其应实施的重点和排序,并用实例对系统诊断结论进行了验证。     

The problem of scale in community resource management

Scale is a fundamental variable in most community resource management programs. This is true both in terms of scale as a management concept (i.e., local, regional, and national level management) as well as a mapping concept (i.e., units on the map per unit on the ground). Julian Steward, the father of human ecology, recognized as early as 1950 that social scientists have failed to develop methods for incorporating the effect of scale in their work. This article seeks to determine whether methods used in plant and animal ecology for assessing the effects of scale are applicable to community resource management. The article reviews hierarchy theory and multiple scales, two methods (one theoretical and the other practical) for dealing with problems that span many scales. The application of these methods to community resource management programs is examined by way of an example.     

Evaluating the effects of local floodplain management policies on property owner behavior

Floodplain management programs have been adopted by more than 85% of local governments in the nation with designated flood hazard areas. Yet, there has been little evaluation of the influence of floodplain policies on private sector decisions. This article examines the degree to which riverine floodplain management affects purchase and mitigation decisions made by owners of developed floodplain property in ten selected cities in the United States. We find that the stringency of such policies does not lessen floodplain property buying because of the overriding importance of site amenity factors. Indeed, flood protection measures incorporated into development projects appear to add to the attractiveness of floodplain location by increasing the perceived safety from the hazard. Property owner responses to the flood hazard after occupancy involve political action more often than individual on-site mitigation. Floodplain programs only minimally encourage on-site mitigation by the owner because most owners have not experienced a flood and many are unaware of the flood threat. It is suggested that floodplain programs will be more effective in meeting their objectives if they are directed at intervention points earlier in the land conversion process.     

Assessing representativeness of places for conservation reservation and heritage listing

Problems arising from application of the representative criterion for conservation and natural heritage evaluation are discussed. An ecological basis to this criterion is suggested that focuses on those key environmental factors dominating biotic response. A methodology is proposed that utilizes computer-based methods of establishing and interrogating spatial data bases (geographic information systems), environmental modeling, and numeric analysis. An example is presented illustrating some of the advantages and limitations of classification and dimension reduction techniques in both defining bioenvironments and displaying their spatial distribution. The advantages of this method for representativeness evaluation are that it maximizes the utility of available data, is explicit and repeatable, and enables large areas to be analyzed at relatively fine scales.     

What are expert systems and how can they contribute to Planning?

The possible role of computer‐based expert systems in town and country planning has yet to be formalised and many planners are not aware of the potential and limitations of software developments in this area. This paper defines expert systems for planners, explains their operation and outlines a possible area, within the development control process, where such systems could provide a beneficial contribution to planning.     

A CATALYST FOR REGIONALIZATION OF RURAL WATER SYSTEMS1

ABSTRACT: The National Regulatory Research Institute has recommended the merger of small rural water districts in the United States. Success at bringing about merger of these districts, which contain fewer than 3,500 customers, has been highly limited. The subject of this paper is a demonstration project that may act as a catalyst to achieve the desired goal of regionalization. A computerized hydraulic data management program (CHDMP) was developed for a case study in Nelson County, Kentucky. University professors, graduate students, and two water utilities’ staffs cooperated in network analysis employing computer hardware and software. The utilities’ staffs were taught the science and technology of hydraulic model preparation, simulation, and analysis for the case study distribution systems. As an integrated system, the model contained 294 pipes, 234 nodes, six pumps, and 11 tanks. Each utility's problem areas were identified and some of the individual and mutual benefits of hydraulic planning were illustrated. A dialogue resulted between the managers. Each manager described his goals and agreed that, although political merger was not feasible at the present time, future economic factors could be a definite influence in reversing that decision.     

USE OF MICROCOMPUTERS FOR THE MANAGEMENT OF WATER QUALITY DATA1

ABSTRACT: Information on raw water quality, treatment process removal efficiency, and distribution system monitoring is essential to the proper management and operation of a water utility system. Microcomputer hardware and software systems using commercially available data base management systems (DBMS) have emerged within the last few years as an effective means of managing, analyzing, and displaying water quality data. Understanding hardware, software, and training requirements is essential to the proper use of these systems. Three types of data base design are common: relational, hierarchical, and network. Only the relational type of data base architecture is widely implemented on microcomputer DBMS. In this paper two examples of the application of DBMS to water utility problems are presented. One example deals with collection and analysis of data concerning the water quality of the Mississippi River. The second example deals with the DBMS as a means of analyzing water quality data in the North Penn Water Authority (NPWA) distribution system.