A serious concern for managers of water resources, pathogens in the urban environment easily enter waters through a number of pathways, including discharge of inadequately treated sewage, stormwater runoff, combined sewer overflows and sanitary sewer overflows. Pathogens in US ambient water bodies are regulated under the Clean Water Act (CWA), while pathogens in drinking water supplies are regu...

A road segmentation technique is proposed based on a mathematical morphology tool called watershed transform. Starting from a coarse marker of the road to be segmented, we modify the gradient image of the scene and compute the watershed transform of this image. The result provides a fair segmentation of the road. The marker itself is produced by using the watershed transform, and a simplified r...

This paper summarizes some results of the authors concerning watershed divides and their use in region merging schemes. The first aspect deals with properties of watershed divides that can be used in particular for hierarchical region merging schemes. We introduce the mosaic to retrieve the altitude of points along the divide set. A desirable property is that, when two minima are separated by a...

Sharma, Sumit, "Developing virtual watersheds for evaluating the dynamics of land use change" (2007). Retrospective Theses and Dissertations. Paper 14524.

Two methods of grid based and image based modeling were put forward respectively to represent the landform of watersheds on the Loess Plateau, China. Many kinds of spatial data such as Digital Elevation Model (DEM), Remote Sensing (RS) images, and photos are utilized to establish the digital 3-D terrains of watersheds on the Loess Plateau, which provides 3-D virtual geographic environments for ...

At the present time, one of the best methods for semiautomatic image segmentation seems to be the approach based on the fuzzy connectedness principle. First, we identify some deficiencies of this approach and propose a way to improve it, through the introduction of competitive learning. Second, we propose a different approach, based on watersheds. We show that the competitive fuzzy connectednes...

In this paper, we provide a basic introduction to several popular cooperative learning activities and explore how these activities might be modified for computer-based science learning activities. We review research that describes science programs that employ collaboration. Then, we describe innovative computerbased tools developed and/or utilized at the University of Hawaii Curriculum Research...

In developing countries, the fraction of treated wastewater effluents being discharged into watersheds have increased over the period of time, which have led to the deteriorations of the qualities of major rivers in developing nations. Consequently, high densities of disease causing bacteria in the watersheds are regularly reported including incidences of emerging Vibrio fluvialis. Vibrio fluvi...

We show that in the continuum limit watersheds dividing drainage basins are Schramm-Loewner evolution (SLE) curves, being described by one single parameter κ. Several numerical evaluations are applied to ascertain this. All calculations are consistent with SLE(κ), with κ = 1.734 ± 0.005, being the only known physical example of an SLE with κ<2. This lies outside the well-known duality conjectur...

Topographic Effects on Stormflow Acidity David Wolock 1 This paper describes the theoretical and observed effects of topography onstormflow acidity in upland, forested watersheds. The theoretical effects were determined by a sensitivity analysis using the hydrologic model TOPMODEL. The observed effects were determined by an analysis of topographic and stormflow acidity data collected from eight...