AUTOMATED EXTRACTION OF DRAINAGE NETWORK AND WATERSHED DATA FROM DIGITAL ELEVATION MODELS1

ABSTRACT: This paper discusses a computer program which extracts a number of watershed and drainage network properties directly from digital elevation models (DEM) to assist in the rapid parameterization of hydrologic runoff models. The program integrates new and established algorithms to address problems inherent in the analysis low-relief terrain from raster DEMs similar to those distributed by the U.S. Geological Survey for 7.5-minute quadrangles. The program delineates the drainage network from a DEM, and determines the Strahler order, total and direct drainage area, length, slope, and upstream and downstream coordinates of each channel link. It also identifies the subwatershed of each channel source and of the left and right bank of each channel link, and assigns a unique number to each network node. The node numbers are used to associate each subwatershed with the channel link to which it drains, and can be used to control flow routing in cascade hydrologic models. Program output includes tabular data and raster maps of the drainage network and subwatersheds. The raster maps are intended for import to a Geographical Information System where they can be registered to other data layers and used as templates to extract additional network and subwatershed information.     

Flooding and erosion hazards on the ontario great lakes shoreline: a human ecological approach to planning and management

Understanding flood and erosion hazards in the context of developing coastal management plans requires an appreciation for variations in climate, geology, vegetation, land uses, human activities and institutional arrangements. On the Great Lakes, fluctuating water levels are characterized by temporal variations in their magnitude and frequency and their impact on flooding and erosion also differ from site to site. The traditional planning and management mechanisms in Ontario, through the use of emergency responses and land use setbacks, have been insufficient in resolving the rising costs of damage to property due to flooding and erosion along the Great Lakes shoreline. There is a need to develop an alternative management model with a focus on understanding hazards in the context of their natural and human components. A case study of the preparation of a resource survey for the Saugeen Valley Conservation Authority illustrates the development of a human ecological approach and its applicability in developing shoreline management plans for the Great Lakes.     

RIVER RECREATION EXPERIENCE OPPORTUNITIES IN TWO RECREATION OPPORTUNITY SPECTRUM (ROS) CLASSES1

The Recreation Opportunity Spectrum (ROS) system is used by the USDA Forest Service and USDI Bureau of Land Management for inventorying, classifying, and managing wildlands for recreation. Different ROS classes from the Colorado and Arkansas Rivers in Colorado were compared, using visitor survey data collected in 1979 and 1981, to see if the different classes offered different recreational experience opportunities. No difference between classes was found. Six possible reasons for not finding a difference are discussed. The usefulness of ROS at the broader levels of planning and the needs at more detailed levels of planning are noted.     

Using groupware to improve the EH&S audit documentation and reporting process

According to Fortune, as of early 1995, some 4,000 companies have purchased Lotus Notes®, the premier entry in an emerging field of software known as groupware. For many companies making the commitment, installation of the software has meant significant capital expenditures as wide area and local area networks and client-server hardware had to be installed to make effective use of Notes' capabilities nationwide and worldwide. A few companies are in the early stages of developing environmental, health, and safety management capabilities. At first blush, the EH&S audit document management process appears to be an ideal application for groupware. It is vitally important that audit tracking systems are put in place and operate effectively. This article shows how groupware can help to achieve this objective.     

ESTIMATING LOW-FLOW QUANTILES FROM DRAINAGE-BASIN CHARACTERISTICS IN NEW HAMPSHIRE AND VERMONT1

ABSTRACT: This study systematically develops, validates, and compares alternative approaches for estimating quantiles of the distribution of annual minimum seven-day-average flows (7Q) for ungaged, unregulated drainage basins in New Hampshire and Vermont via regression on map-measurable drainage-basin characteristics. At 47 gaging stations in the region, the hypotheses that 7Q is log normally distributed and serially independent are not rejected, and the regional average spatial correlation is R= 0.35. Step-forward examination of a suite of potential predictor variables revealed that logarithm of drainage area, mean elevation, and fraction of basin covered with sand and gravel deposits are significant predictors of quantiles of 7Q. The regression equations were incorporated into four approaches to estimate the 7Q value with a nonexceedence probability of 0.1, 7Q10. Comparison of observed values and values predicted via a delete-one jackknife resampling validation indicates that one of the approaches gives estimates with acceptable bias and precision, with median relative error of 33 percent and prediction error of 64 percent. This is equivalent to the precision obtainable with only one to two years of gaging records. In spite of this limited precision, the approaches developed herein are useful for predicting 7Q quantiles at ungaged sites. Further improvement in precision will likely be possible only by exploiting the spatial correlation of annual 7Q.     

Magnetic particle technology in environmental remediation and wildlife rehabilitation

The use of magnetic particles in environmental remediation and wildlife rehabilitation is currently under investigation at Victoria University, in collaboration with the Phillip Island Research Centre, Victoria, Australia. Iron powder has been shown to be very effective for the magnetic cleansing of feathers and plumage and is almost ideal for this purpose, being non-toxic, a non-irritant and recyclable. Detailed investigations have demonstrated that by varying particle size, particle structure and surface texture, the efficacy of oil removal from feathers and plumage can be successfully manipulated. In this regard, it is possible to identify a grade of iron powder whereby, within experimental error, effectively 100% removal of a variety of fresh contaminants from different matrices, including feathers, can be achieved. Our investigations have been extended to the application of such particles to the successful removal of tarry and weathered/tarry contamination. The results of these investigations have indicated that, for such contaminants, removals ranging from 97–99% may be achieved. Magnetic particle technology may also be adapted for the screening of pre-conditioning agents that can further assist in the removal of tarry and weathered/tarry contamination from feathers. These investigations suggest that magnetic particles could have an important role to play in environmental remediation and wildlife rehabilitation as a clean and effective technology.     

The scientific foundations of clinical enzymology

Clinical enzymology is the study of the activity and properties of enzymes in specimens (usually of blood) taken from patients, as an aid to the diagnosis and understanding of disease. Research in many areas of enzymology is undertaken to strengthen the foundations on which the clinical interpretation of such enzyme measurements rests. Some aspects of this research are briefly described.     

ANALYSIS OF LAS,ABS AND COMMERCIAL DETERGENTS BY TWO-PHASE TITRATION1

ABSTRACT: A two-phase titration method was developed and evaluated to determine the concentration of linear alkylate sulfonate (LAS), branched-chain alkyl benzene sulfonate (ABS), dishwashing detergents, and laundry detergents in water. This method is capable of quantitatively determining anionic surfactants in either fresh water or saline water and it is therefore superior to the widely used Methylene Blue Method. To simplify the titration method for adoptation to remote field utilization, a field test kit was developed. This test kit includes only a separatory funnel, a titration burette, a set of liquid measuring apparatus, and some chemicals. Emphasis was placed on compactness of the kit and simplicity in the test manipulation, so that its operation can be performed by relatively unskilled wastewater monitoring personnel.