LAW,HYDROLOGY, AND SURFACE-WATER SUPPLY IN THE UPPER COLORADO RIVER BASIN1

ABSTRACT: Law and hydrology are inextricably woven together in the pattern of water resource development in the west. The former attempts to allocate a limited and valuable resource as the latter tries to define the limits of the resource. In the past an inadequate data base has made hydrologic estimates difficult and political factors have pushed the law into possibly conflicting commitments in the Colorado River Basin. Through the use of tree-ring research, hydrologists have produced a more definitive data base and placed water allocations such as the Colorado River Compact of 1922 in a clearer long-term perspective. This data base leads to the conclusion that the surface-water supply is about 13.5 million acre-feet per year. This hydrologic limit must be apportioned within an existing legal framework - the “Law of the River.” As development approaches the resource limit in the Upper Colorado River Basin, lawyers and hydrologists must act in concert toward the equitable solution of allocation and reallocation problems.     

DECISION-MAKING IN THE DEVLOPMENT OF URBAN WATERFRONTS FOR PARK/BUSINESS USE1

Abstract: Opportunities for the development of an amalgam of park and leisure-oriented commercial establishments in urban-core waterfont settings exist in many U.S. cities. Public awareness of the need to enhance the environmental quality of these waterfont areas has resulted in a demand for planning and implementation action. However, the lack of understanding of urban political systems has been an inhibiting factor in the development of this park/ business concept. The major factors that influence the decision-making process leading to the development of urban-core waterfronts for park/business use are identified inthis paper. Understanding this decision-making process can aid project implementation and avoid waste of planning effort in time, dollars, and productivity.     

THE RELATIONSHIP BETWEEN BEST MANAGEMENT PRACTICES AND RECEIVING-WATER STANDARDS1

ABSTRACT: An important enforcement question is, “What should be the relationship between ‘Best Management Practices’ (BMP) and receiving-water standards?” Nonpoint pollution dischargers are concerned about implementing a BMP program, only to find themselves in violation because receiving-water standards still have not been met. They are also concerned about the procedures a regulatory agency will utilize to determine the relative success of a BMP program. Successful management of nonpoint pollution requires that these concerns be addressed. Three alternative relationships have been developed. The recommended alternative is to implement the BMP program and use standards as a measure of the effectiveness of the program. Failure to achieve the standards would lead to a reevaluation of the BMP program. Enforcement activities against nonpoint dischargers would be restricted to the failure on their part to implement the previously agreed upon BMP program. Recommendations are also made as to measures regulatory agencies should take if their procedures to judge the relative success of a BMP program are to be technically and politically effective.     

COMPARING METHODS OF HYDROLOGIC REGIONALIZATION1

ABSTRACT: Data splitting is used to compare methods of determining “homogeneous” hydrologic regions. The methods compared use cluster analysis based on similarity of hydrologic characteristics or similarity of characteristics of a stream's drainage basin. Data for 221 stations in Arizona are used to show that the methods, which are a modification of DeCoursey's scheme for defining regions, improve the fit of estimation data to the model, but that is is necessary to have an independent measure of predictive accuracy, such as that provided by data splitting, to demonstrate improved predictive accuracy. The methods used the complete linkage algorithm for cluster analysis and computed weighted average estimates of hydrologic characteristics at ungaged sites.     

A Management Systems Review of the Superfund RI/FS: Opportunities for Streamlining

The Management Systems Review is an important component of EPA’s quality assurance program. MSRs enable managers to assess the effectiveness of environmental data operations and the quality assurance/ quality control activities designed to ensure that the results are of the expected quality. These reviews inform managers about aspects of the environmental data operation that are working well and those which may warrant some improvement. A recent review of the Superfund remedial investigation/feasibility study (RI/FS) has shown that the MSR is an excellent tool for providing a systematic definition of complex environmental data operations and for enabling a thorough analysis of these operations. The MSR utilized information gathered from interviews of Regional staff and management and from case studies of recently completed RI/FSs. The findings indicated that environmental data play an important role in most RI/FS decisions and that thorough and structured scoping is critical to the effectiveness of the RI/ FS. Analysis of the RI/FS process using a comprehensive flow model identified several opportunities for changes that may increase efficiency in data collection and the reliability of RI/FS decisions. These changes provide for more effective scoping activities, a streamlined feasibility study, and increased use of treatability studies during the RI. A pilot demonstration of these process changes is being planned for a Regional RI/FS.     

Source Apportionment of Phoenix PM2.5 Aerosol with the Unmix Receptor Model

Abstract

The multivariate receptor model Unmix has been used to analyze a 3-yr PM_2.5 ambient aerosol data set collected in Phoenix, AZ, beginning in 1995. The analysis generated source profiles and overall average percentage source contribution estimates (SCEs) for five source categories: gasoline engines (33 ± 4%), diesel engines (16 ± 2%), secondary SO₄ ^2? (19 ± 2%), crustal/soil (22 ± 2%), and vegetative burning (10 ± 2%). The Unmix analysis was supplemented with scanning electron microscopy (SEM) of a limited number of filter samples for information on possible additional low-strength sources. Except for the diesel engine source category, the Unmix SCEs were generally consistent with an earlier multivariate receptor analysis of essentially the same data using the Positive Matrix Factorization (PMF) model. This article provides the first demonstration for an urban area of the capability of the Unmix receptor model.     

Monitoring Australian Rangeland Sites Using Landscape Function Indicators and Ground- and Remote-Based Techniques

If the goal for managing rangelands is to achieve a balance between production and conservation, then monitoring is essential to detect change and apply corrective action. In some range-land areas of northern Australia, monitoring has detected a tilt in the production-conservation balance towards excessive production. How big is this imbalance? Can it shift back? Robust monitoring is needed to answer these questions. The aim is to know what to monitor, and where. For example, to detect changes caused by livestock on rangeland forage production and soil erosion, indicators linking grazing disturbances to landscape function are needed, that is, indicators that signal how well landscapes are capturing, concentrating, and utilizing scarce water, nutrient, and organic resources. Studies in Australia and the USA document that simple vegetation and soil patch attributes can be measured as indicators of the 'state of health' of landscape function. For example, field and remote sensing-based grazing studies in Australia document that landscapes with a high cover of perennial plant patches function effectively to capture runoff water and nutrients in sediments, whereas landscapes with a low cover of these patches do not — they are dysfunctional — as indicated by large patches of bare soil. Aerial videography is proving to be a robust technique for measuring indicators of landscape function such as small patches of vegetation and the extent of bare soil. These indicators typically have a sigmoidal response to grazing impacts. We illustrate that if these indicators are measured on monitoring sites established near the sigmoidal 'point of inflection’ then small changes in these indicators can be detected.     

The importance of differentiating urban and rural phenomena in examining the unequal distribution of locally desirable land

Previous research addressing the unequal distribution of locally desirable land (LDL) has mainly ignored their associated environments (i.e., rural or urban). However, this study proposed a new framework that treats rural and urban regions separately. In rural areas, the LDLs included all public lands. In urbanized areas, the LDLs were defined as green open spaces. Potential inequities in the distribution of LDL were assessed with respect to socioeconomic characteristics of residents in the State of Georgia. Using US Census Bureau Data (2000), Census Block Groups (CBGs) adjacent to LDLs were compared to CBGs outside of LDLs on four socioeconomic variables (per capita income, occupation, education, and race) in urban, suburban and rural environments. Results showed that CBGs adjacent to LDLs were composed of statistically significant upper-class communities containing fewer blue-collar workers, more whites, and higher income and higher educated people in rural, suburban and urban areas.