Filters: Tags: water quantity (X)14 results (82ms)
Synopsis: This study analyzed the effects of vegetation change on hydrological fluctuations in the Columbia River basin over the last century using two land cover scenarios. The first scenario was a reconstruction of historical land cover vegetation, c. 1900. The second scenario was more recent land cover as estimated from remote sensing data for 1990. The results show that, hydrologically, the most important vegetation-related change has been a general tendency towards decreased vegetation maturity in the forested areas of the basin. This general trend represents a balance between the effects of logging and fire suppression. In those areas where forest maturity has been reduced as a result of logging, wintertime...
This community catalog serves the USGS Pennsylvania Water Science Center. The Water Science Center's mission is to collect, analyze and disseminate the impartial hydrologic data and information needed to wisely manage water resources for the people of the United States and the Commonwealth of Pennsylvania. In Pennsylvania, the USGS's water-resources roots date back to the late 1800's, with the initiation of streamflow gaging on the Delaware and Susquehanna Rivers and the evaluation of groundwater resources in various parts of the Commonwealth. Today, the Pennsylvania Water Science Center's cadre of nearly 80 scientists, technicians, and support staff in New Cumberland, Exton, Pittsburgh, and Williamsport work in...
Urbanization of aquatic systems: degradation thresholds, stormwater detection, and the limits of mitigation.
Conclusions:Within a watershed, about 10% of development is not subject to drainage regulations resulting in cumulative effects from urbanization that significantly degrade watersheds. Instead of regulatory thresholds (e.g. 10% EIA), process controls are required to mitigate the impacts of urbanization on aquatic systems. Without these controls, strict development limits are the only way to limit watershed degradation.Thresholds/Learnings:The study cautions against the use of discrete “thresholds” to predict specific physical and biological effects, but does suggest that thresholds are appropriate indicators for when the perception and tolerance of watershed impacts triggers a regulatory response.
Conclusions:Report reviews how forests and their management affect the quality and quantity of downstream municipal water supplies in the state of OregonThresholds/Learnings:When >25% of the watershed's forest cover is clearcut in a short period of only a few months, there is a measurable increase in annual streamflows from the watershed.
Water Quantity and Quality Benefits from Wetland Conservation and Restoration in the Broughton’s Creek Watershed
Conclusions:Loss of wetland cover over a 40 year period resulted in increased peak flows, increased sediment, phosphorus and nitrogen flows, and decreased waterfowl populations.Thresholds/Learnings:
This dataset depicts water use by sector at the county level in the U.S., as estimated by the USGS. Attributes of this dataset describe the use of water by different sectors, including public supply, industry, and irrigation. Care should be exercised when using this dataset. Data for certain attributes were missing; these were coded as the value 0. These 0 values should not be taken to represent that the quantity of water use is indeed 0, but rather that the data were missing from the original dataset. For more information about this dataset and associated analyses for other time periods, please see: http://water.usgs.gov/watuse/
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Conclusions:Document serves as a guide to consistent reporting for Alberta’s State of the Watershed Reports. It outlines a framework for reporting watershed conditions by providing specific criteria and direction to guide consistency in reporting. Framework includes major indicators of watershed health, including section on land cover and pattern indicators which provide critical thresholds for road density impacts to wildlifeThresholds/Learnings:Road density thresholds: grizzly bears- 0.4 km/km2; elk- 0.62 km/km2; black bears- 1.25 km/km2. Road densities for bull trout: 0.0-0.1 km/km2 = low risk; 0.1-0.2 km/km2 = moderate risk; 0.2-0.6 km/km2 = high risk; 0.6-1.0 km/km2 = very high risk; >1.0 km/km2 = extripation....
Indicators for Assessing Environmental Performance of Watersheds in Southern Alberta. Assessment report
Conclusions:Presents condition and pressure indicators for land, water quantity, water quality, and aquatic and riparian systems, as a series of categorized indicators of environmental quality. These broadly include: land quality condition indicators, land use pressure indicators, water quantity pressure indicators, water quality pressure indicators, and indicators of aquatic and riparian ecosystem health.Thresholds/Learnings:
A comparison of hydrologic simulations in the lower Apalachicola-Chattahoochee-Flint River Basin, southeastern United States. This project provides technical assistance in integrating the Waterfall instream flow models developed for the South Atlantic LCC by RTI with the PRMS models being developed in the neighboring Gulf Coastal Plains and Ozarks LCC.