This paper is devoted to the study of watershed algorithms behavior. Through the introduction of a concept of pass value, we show that most classical watershed algorithms do not allow the retrieval of some important topological features of the image (in particular, saddle points are not correctly computed). An important consequence of this result is that it is not possible to compute sound meas...

/ Watershed-based planning has been held as a vanguard for integrated ecosystem management based on a collaborative process. Watershed managers, however, must contend with conflicts that run much deeper than interests for economic development versus sustaining ecosystem health. With data from a survey of members of watershed organizations, we characterize the valued-based conflicts that watersh...

More than three decades have elapsed since the passage of the Federal Water Pollution Control Act with its stated goal of zero discharge of pollutants into the nation's waterways. Yet, water quality remains poor in many locations and considerable loading of pollutants continues. This is particularly true for agricultural sources of water pollution and is typified by the Upper Mississippi River ...

Watershed nutrient management is essential in minimizing the eutrophication rate of reservoirs. A shortcoming in nutrient management of watershed-reservoir systems has been the lack of successful linking of watershed and water body models to evaluate impact of watershed management options on reservoir water quality. The objectives of this research were to 1) calibrate and validate a Soil and Wa...

In this paper, we investigate the links between the flooding paradigm and the topological watershed. Guided by the analysis of a classical flooding algorithm, we introduce several notions that help us to understand the watershed: minima extension, extension map, and pass values. We investigate the possibility for a flooding to produce a topological watershed, and conclude that this is not feasi...

this study aims to quantify the impacts of land use changes on ecosystem service value during large scale land development, and to provide key information for both economic development and policy makers for eco-environmental protection. the study area locates in manas river watershed which is a typical land development region in northwest china. landsat mss/tm/etm+ images in 1976, 1989, 1999 an...

As originally conceived, watershed analysis is a synthesis of information that focuses on issues important to a particular watershed in the context of larger eco-scape scales. Some practitioners of watershed analysis have ascended a steep and unfamiliar learning curve of synthesizing between disciplines and agencies and addressing ecosystem issues at a large scale. Yet, after two years of inter...

The mission of the Green Visions Plan for 21st Century Southern California is to offer a guide to habitat conservation, watershed health and recreational open space for the Los Angeles metropolitan region. The Plan will also provide decision support tools to nurture a living green matrix for southern California. Our goals are to protect and restore natural areas, restore natural hydrological fu...

This paper introduces the object counting using the mark controlled watershed transforms. Watershed transform is usually adopted for image segmentation in the area of image processing and image analysis because it always generates closed contours for each region in the original image. This method is good choice for image segmentation in the field of mathematical morphology. In this paper we are...

Public participation in environmental management is increasingly common across many natural resource sectors. Environmental policies in the water resources sector, in particular, depend upon both computer-based watershed modeling activities and public participation in watershed management decisions, though the integration of participation in watershed modeling remains uncommon. Case studies of ...