نتایج جستجو برای: watersheds ie

تعداد نتایج: 25913  

2012

PROTO-INDO-EUROPEAN is the traditional name given to the ancestor language of the Indo-European family that is spread from Iceland to Chinese Turkestan and from Scandinavia to the Near East. A PROTO-LANGUAGE (Gk. prõtos ‘first’) refers to the earliest form of a language family presupposed by all of its descendants. There will forever be major gaps in the reconstruction of proto-languages, but a...

1999
Michael J. Kearns

In this paper we introduce an extension of the Probably Approximately Correct (PAC) learning model to study the problem of learning inclusion hierarchies of concepts (sometimes called is-a hierarchies) from random examples. Using only the hypothesis representations output over many different runs of a learning algorithm, we wish to reconstruct the partial order (with respect to generality) amon...

2015
Scott Bauer Jennifer Olson Adam Cockrill Michael van Hattem Linda Miller Margaret Tauzer Gordon Leppig

Marijuana (Cannabis sativa L.) cultivation has proliferated in northwestern California since at least the mid-1990s. The environmental impacts associated with marijuana cultivation appear substantial, yet have been difficult to quantify, in part because cultivation is clandestine and often occurs on private property. To evaluate the impacts of water diversions at a watershed scale, we interpret...

1999
T. A. Cochrane

Two different methods utilizing geographical information systems (GIS) and digital elevation models (DEMs) are described and evaluated for applying the Water Erosion Prediction Project (WEPP) model to assess water erosion and runoff in small watersheds. The first approach, called the Hillslope method, presents an automated method for the application of WEPP through the extraction of hillslopes ...

2005
John A. Moody David A. Kinner

Predicting runoff and erosion from watersheds burned by wildfires requires an understanding of the spatial structure of both hillslope and channel drainage networks. We investigate the small-scale and large-scale structures of drainage networks using field studies and computer analysis of 30-m digital elevation model. Topologic variables were derived from a composite 30-m DEM, which included 14...

Journal: :Journal of environmental quality 2007
X Wang A Saleh M W McBroom J R Williams L Yin

Hydrologic/water quality models are increasingly used to explore management and policy alternatives for managing water quality and quantity from intensive silvicultural practices with best management practices (BMPs) in forested watersheds due to the limited number of and cost of conducting watershed monitoring. The Agricultural Policy/Environmental eXtender (APEX) model was field-tested using ...

2015
E. Terrence Slonecker Lesley E. Milheim

The spatial footprint of unconventional (hydraulic fracturing) and conventional oil and gas development in the Marcellus Shale region of the State of Pennsylvania was digitized from high-resolution, ortho-rectified, digital aerial photography, from 2004 to 2010. We used these data to measure the spatial extent of oil and gas development and to assess the exposure of the extant natural resources...

2012
Matthew S. Buffleben

Although many sediment budgets estimate the effects of logging, few have considered the potential impact of timber harvesting on stream density. Failure to consider changes in stream density could lead to large errors in the sediment budget, particularly between the allocation of natural and anthropogenic sources of sediment. This study conducted field surveys in randomly selected catchments in...

2017
Brian Buma Ben Livneh

Water is one of the most critical resources derived from natural systems. While it has long been recognized that forest disturbances like fire influence watershed streamflow characteristics, individual studies have reported conflicting results with some showing streamflow increases postdisturbance and others decreases, while other watersheds are insensitive to even large disturbance events. Cha...

Hot spots are often associated with places where an abnormal process has occurred. Accordingly, their identification can help experts and managers to scrutinize the state of health and sustainability, from an ecological point of view. The present study was therefore conducted to analyze the spatial autocorrelation and identify hot spots of 11 landscape metrics, the new Runoff Landscape Index (R...

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