Watershed segmentation/transform is a classical method for image segmentation in gray scale mathematical morphology. Nevertheless watershed algorithm has strong recursive nature, so straightforward parallel one has a very low efficiency. Firstly, the advantages and disadvantages of some existing parallel algorithms are analyzed. Then, a Further Optimized Parallel Watershed Algorithm (FOPWA) is ...

The stochastic watershed is a probabilistic segmentation approach which estimates the probability density of contours of the image from a given gradient. In complex images, the stochastic watershed can enhance insignificant contours. To partially address this drawback, we introduce here a fully unsupervised multi-scale approach including bagging. Re-sampling and bagging is a classical stochasti...

Permafrost and fire are important regulators of hydrochemistry and landscape structure in the discontinuous permafrost region of interior Alaska. We examined the influence of permafrost and a prescribed burn on concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and other solutes (NO 3 , Ca 2C, KC, Mg2C, NaC) in streams of an experimentally burned watershed and tw...

We analyzed data from riffle and snag habitats for 39 small cold water streams with different levels of watershed urbanization in Wisconsin and Minnesota to evaluate the influences of urban land use and instream habitat on macroinvertebrate communities. Multivariate analysis indicated that stream temperature and amount of urban land use in the watersheds were the most influential factors determ...

A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a previous study with nested modeling for the UMRW that required both the Agricultural Policy EXtender (APEX) model and SWAT. In the nested modeling appr...

Watershed protection may be a fine idea, but how much does it cost? How does it change the bottom line for the region, the development community, landowners and residents alike? This question is increasingly being posed to those advocating better watershed protection. In this article, we review economic research on the costs and benefits of employing watershed management tools and tally the sco...

Watershed segmentation/transform is a classical method for image segmentation in gray scale mathematical morphology. Nevertheless watershed algorithm has strong recursive nature, so straightforward parallel one has very low efficiency. Firstly, the advantages and disadvantages of some existing parallel algorithms are analyzed. Secondly, a Further Optimized Parallel Watershed Algorithm (FOPWA) i...

Watershed delineation is a process for defining a land area that contributes surface water flow to a single outlet point. It is a commonly used in water resources analysis to define the domain in which hydrologic process calculations are applied. There has been a growing effort over the past decade to improve surface elevation measurements in the U.S., which has had a significant impact on the ...

Soil erosion has been recognized as one of the major threats to our environment and water quality worldwide, especially in China. To mitigate nonpoint source water quality problems caused by soil erosion, best management practices (BMPs) and/or conservation programs have been adopted. Watershed models, such as the Annualized Agricultural Non-Point Source Pollutant Loading model (AnnAGNPS), have...

We analyzed Landsat MSS and ETM+ images to detect 25-year land-cover change (1976-2001) in the critical Taguibo Watershed in Mindanao Island, Southern Philippines. This watershed has experienced historical modifications of its land-cover due to the presence of logging industries in the 1960s, and continuous deforestation due to illegal logging and slash-and-burn agriculture in the present time....