The reflection method of line intercept sampling to eliminate boundary bias

When a line transect overlaps the boundary of the sampled region, it can be reflected back on top of itself into the region, thereby making it possible to include elements near the edge twice from the same transect. A practical advantage of doing so is the reduction of field time and effort compared to the customary procedure of folding the transect back into another part of the region. An estimator is presented which accounts for this procedure in a way that preserves design-unbiased estimation.     

MONITORING OPERATIONS PERFORMANCE IN LARGE-SCALE PUBLIC IRRIGATION SYSTEMS IN INDONESIA1

ABSTRACT: Different allocation and delivery performance ratios are used to assess operations performance in a large scale public irrigation system in Indonesia. Results from this analysis indicate that field management practices deviate substantially from the official operating procedures. The lack of application of a single, standardized procedure for planning water allocations represents a serious constraint to effective monitoring and evaluating system performance. Underestimated and unrealistic planned allocations becomes the justification for overdiversion of water, and has the effect of undermining the resolve of managers to see to it that actual flows meet planned flows. Miscalculating planned allocations, poor matches between planned flows and actual deliveries, overdiversion and misreporting have economic consequences as well. For example, strict adherence to the standard operating rule during the second dry season of 1987 would have resulted in 19,070,000 m³ less water diverted into the irrigation system from the Brantas River or, at a conservative estimate of $1.78 per 100 m³ water, a savings of $339,500. Scope exists for making improvements in management by closer adherence to the standard delivery rule, which will also facilitate proper monitoring and evaluation.     

THE ENVIRONMENTAL DISPLAY MANAGER: A TOOL FOR WATER QUALITY DATA INTEGRATION1

ABSTRACT: The Environmental Display Manager, EDM, is a development system on an IBM 3090 mainframe at the U.S. EPA National Computer Center in Research Triangle Park, North Carolina. EDM provides mapping, display, analysis support, and information management capabilities to workstations located across the United States, and connected to EPA through federal, state, academic, and private communications networks. Through interactive software, EDM can quickly support analyses, create maps and graphics, and generate reports that integrate millions of pieces of environmental data. The concept of EDM is to provide easy access to environmental information, to provide automated environmental analyses and reports, and then to provide data, graphics, images, text, and documents that can be used by numerous output devices, software packages, and computers. The mapping cumponent works with an electronic version of the 54,000 7.5 minute quad sheets of the U.S. Geological Survey. The software also works with a hydrographic data base of the surface waters of the United States. With the maps, a user can look at the rivers in any state, can zoom in on a small pond, and can overlay and identify particular features such as industrial waste dischargers and factories. The hydrography allows routing for modeling programs, identification of upstream and downstream components, and linkage of environmental features associated with surface waters. Alternatively, users can query data based on latitude/longitude, city name, EPA permit number, state agency and station code, river name or number, and river cataloging unit. The maps can be overlaid with roads and environmental sites such as: municipal and industrial dischargers, Superfund sites, public drinking water supplies, water quality monitoring stations, stream gages, and city locations. Retrievals from related systems can be performed for selected sites creating graphics showing water quality trends, discharge monitoring reports, and permit discharge limits.     

A national critical loads framework for atmospheric deposition effects assessment: III. Deposition characterization

Methods are discussed for describing patterns of current wet and dry deposition under various scenarios. It is proposed that total deposition data across an area of interest are the most relevant in the context of critical loads of acidic deposition, and that the total (i.e., wet plus dry) deposition will vary greatly with the location, the season, and the characteristics of individual subregions. Wet and dry deposition are proposed to differ in such fundamental ways that they must be considered separately. Both wet and dry deposition rates are controlled by the presence of the chemical species in question in the air (at altitudes of typically several kilometers in the case of wet deposition, and in air near the surface for dry). The great differences in the processes involved lead to the conclusion that it is better to measure wet and dry deposition separately and combine these quantifications to produce “total deposition” estimates than to attempt to derive total deposition directly. A number of options for making estimates of total deposition to be used in critical loads assessment scenarios are discussed for wet deposition (buckets and source receptor models) and for dry deposition (throughfall, micrometeorology, surrogate surfaces and collection vessels, inference from concentrations, dry-wet ratios, and source-receptor models). The research described in this article has been funded by the US Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory in Corvallis, Oregon, through contract #68-C8-0006 with ManTech Environmental Technology, Inc., and Interagency Agreement #1824-B014-A7 with the U.S. Department of Energy and at Oak Ridge National Laboratory managed by Martin Marietta Energy Systems, Inc., under Contract DE-AC05-84OR21400 with the US Department of Energy. Environmental Sciences Division Publication No. 3905. It has been subjected to the Agency’s peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.     

A national critical loads framework for atmospheric deposition effects assessment: I. Method summary

The United States Environmental Protection Agency (EPA), with the assistance of the US Department of Energy (DOE) and the National Oceanographic and Atmospheric Administration (NOAA) is examining the utility of a critical loads approach for evaluating atmospheric pollutant effects on sensitive ecosystems. A critical load has been defined as, “a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge.” Working in cooperation with the United Nations Economic Community for Europe’s (UN-ECE) Long Range Transboundary Air Pollution (LRTAP) Convention, the EPA has developed a flexible, six-step approach for setting critical loads for a range of ecosystem types. The framework is based on regional population characteristics of the ecosystem(s) of concern. The six steps of the approach are: (1) selection of ecosystem components, indicators, and characterization of the resource; (2) definition of functional subregions; (3) characterization of deposition within each of the subregions; (4) definition of an assessment end point; (5) selection and application of models; and (6) mapping projected ecosystem responses. The approach allows for variable ecosystem characteristics and data availability. Specific recognition of data and model uncertainties is an integral part of the process, and the use of multiple models to obtain ranges of critical loads estimates for each ecosystem component in a region is encouraged. Through this intercomparison process uncertainties in critical loads projections can be estimated. The research described in this article has been funded by the US Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory in Corvallis, Oregon, through contract #68-C8-0006 with Man Tech Environmental Technology, Inc. It has been subjected to the agency’s peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorse ment or recommendation for use.     

SUMMARY OF MODIFICATIONS OF THE U.S. GEOLOGICAL SURVEY MODULAR,FINITE-DIFFERENCE,GROUND-WATER FLOW MODEL TO READ AND WRITE GEOGRAPHIC INFORMATION SYSTEM FILES1

ABSTRACT: The U.S. Geological Survey modular, three-dimensional, finite-difference, ground-water flow model, commonly called MODFLOW, has been modified so that it can read and write files used by a geographic information system (GIS). The modified model program is called MODFLOWARC. The design of MODFLOWARC parallels the design of the ground-water flow model program MODFLOW. The names of the variables, modules, and submodules used to explain the operations of MODFLOWARC were derived from the names used in MODFLOW. During the data input phase, MODFLOWARC reads array control records similar to the original control records of MODFLOW, except an additional variable is added. This additional variable is the name of the computer files containing array data in GIS format. Data output is achieved by setting record/input flags and by supplying a variable that is the name of the directory where the output data will be recorded. The modifications to MODFLOW were minimized so that MODFLOWARC will operate on an existing ground-water flow model without modifying array control records.     

USING VALUES IN PLANNING WASTEWATER FACILITIES FOR METROPOLITAN SEATTLE1

ABSTRACT: This paper uses the fundamental values of decision makers to guide a long-term wastewater planning process at Seattle Metro, a major utility district. Multiattribute value assessment is used to elicit the objectives of several elected officials and other key decision makers. The results are structured into a fundamental objectives hierarchy and a means-ends objectives network. A set of measures to indicate the performance of planning alternatives in terms of the fundamental objectives is developed. Preliminary value tradeoffs between objectives are elicited from several elected officials. The results of these steps are useful for many aspects of long-term planning: facilitating communication about values and priorities; designing attractive alternatives that are more likely to serve stakeholder interests; identifying information needed to evaluate alternatives; clarifying the relative importance of information about different impacts; providing a basis for quantitative evaluation of the alternatives with multiple objective analysis; and focusing attention on key tradeoffs that will affect the choice of alternatives.