Search results for " watershed"

The use of zooplankton metrics to determine the trophic status and ecological potential: An approach in a large Mediterranean watershed.

2021

In the European Water Framework Directive, zooplankton was not included as a Biological Quality Element despite its important place in the aquatic trophic web. In the present study on zooplankton abundances and biomasses, we used several metrics to test their ability to detect differences among trophic statuses and ecological potential levels, and collected a large sum of data in more than 60 reservoirs at Ebro watershed, on more than 300 sampling occasions over 10 years. Our results indicate that most zooplankton metrics are correlated to environmental variables that determine reservoirs’ trophic states, especially chlorophyll a and total phosphorus. The metrics with better sensitivity to …

SVG rendering for internet imaging

2006

The SVG (scalable vector graphics) standard allows representing complex graphical scenes by a collection of graphic vectorial-based primitives, offering several advantages with respect to classical raster images such as: scalability, resolution independence, etc. In this paper we present a full comparison between some advanced raster to SVG algorithms: SWaterG, SVGenie, SVGWave and some commercial tools. SWaterG works by a watershed decomposition coupled with some ad-hoc heuristics, SVGenie and SVGWave use a polygonalization based respectively on data dependent and wavelet triangulation. The results obtained by SWaterG, SVGenie and SVGWave are satisfactory both in terms of perceptual measur…

A comparison of statistical methods and multi-criteria decision making to map flood hazard susceptibility in Northern Iran

2018

In north of Iran, flood is one of the most important natural hazards that annually inflict great economic damages on humankind infrastructures and natural ecosystems. The Kiasar watershed is known as one of the critical areas in north of Iran, due to numerous floods and waste of water and soil resources, as well as related economic and ecological losses. However, a comprehensive and systematic research to identify flood-prone areas, which may help to establish management and conservation measures, has not been carried out yet. Therefore, this study tested four methods: evidential belief function (EBF), frequency ratio (FR), Technique for Order Preference by Similarity To ideal Solution (TOP…

Does lake age affect zooplankton diversity in Mediterranean lakes and reservoirs? A case study from southern Italy

2010

Zooplankton assemblages of 51 lacustrine environments located in the middle of the Mediterranean Region were analysed to evaluate the existence of an ‘age effect’ in determining their structure. The analysed datasets refer to two different geographic areas, one comprising 30 natural and artificial lakes in Sicily and the other an arrangement of 21 analogous aquatic ecosystems located at the bottom of the Italian Peninsula, a more pristine area called Southern Apennine region. Most of the natural lakes are of post-glacial origin. The artificial lakes in both datasets were built in the last century and offer the opportunity to evaluate the possible short-term effects of ageing on the structur…

Advanced SVG Triangulation/Polygonalization of Digital Images

2005

Advanced SVG Rendering of Digital Images

2005

SVG Rendering by Watershed Decomposition

2005

Effects of morphology on watershed actual evapotranspiration estimation by means of SEBAL model

2008

Transformations Accompanying a Shift from Surface to Drip Irrigation in the Cànyoles Watershed, Valencia, Spain

2017

Drip irrigation is widely promoted in Spain to increase agricultural production and to save water. In the Cànyoles watershed, Valencia, we analysed the consequences of change from surface irrigation to drip irrigation over the past 25 years. There were a number of transformations resulting from, or accelerated by, this change including the 1) intensification of well construction causing a redistribution in access to groundwater, water shortages and a lowering of the groundwater table; 2) expansion of irrigation into former rain-dependent uphill areas resulting in increased water use; 3) shift to higher- value monoculture fruit crops, but with associated higher crop water requirements; 4) in…