Search results for "River"

Effect of Vegetation on Fluvial Erosion Processes: Experimental Analysis in a Laboratory Flume

2013

Abstract The plane evolution of a meander wave is determined by the erosion processes at the banks. Particularly, the outer- bank is considerably vulnerable to the erosion processes. Indirect techniques, which act upon the reduction of the effect of the cross-circulation motion, have been recently proposed to limit the outer-bank erosion. This paper shows preliminary results on the role played by vegetation on cross-circulation motion. The analysis is conducted on the basis of experimental data collected in a large amplitude meandering channel constructed at the hydraulic laboratory of DICAM. Maps describing the cross-stream flow, both over the no-vegetated bed and over the vegetated bed, a…

STOP 1: Lower Gauja spillway valley at Sigulda

2014

STOP 9: Upper Daugava spillway valley and associated gully network at Vasargelišķi

2014

Two-Dimensional Hydraulic Modeling and Analysis of Morphological Changes in the Palancia River (Spain) During a Severe Flood Event on October 2000

2013

This paper analyzes the possibilities that mathematical models offer to reconstruct flood events, and to predict their erosional and sedimentary effects. To that end, the severe flood event of October 2000 of the Palancia River (Valencia, Spain) is assessed. The hydraulic reconstruction was performed with the software GUAD 2D, a two-dimensional mathematical simulation model for shallow water conditions. The results obtained from the mathematical model and the hydraulic-sedimentological analysis were compared with the flood-related features mapped by means of geomorphologic photo-interpretation and field observations. This comparative study illustrates that these models constitute a powerful…

Is the riparian habitat creation an effective measure of plant conservation within the urbanized area?

2015

The study presents results of habitat creation and riparian vegetation recovery in artificial oxbow lakes in urbanized area within the large river valley. The investigation of open water, rush and wet meadows flora and vegetation in three ponds located in the city centre of Opole was conducted in years 2001–2013. Oxbow lakes were constructed as a compensation measure and no vegetation was transplanted into the ponds on purpose. 13-years observation showed that (1) the red-listed species are able to spontaneous reoccurrence after habitat restoration, but they can thrive only in first years of oxbow lakes recolonisation process, (2) there are some restoration constraints, especially in relati…

The role of inorganic and organic nutrients on the development of phytoplankton along a transect from the Daugava River mouth to the Open Baltic, in …

2003

Abstract The importance of dissolved silicate (DSi), dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON), phosphate and dissolved organic phosphorus (DOP) on algal growth is analysed for the Gulf of Riga and the adjacent open Baltic Sea. The results of three cruises (May, June, and July, 1999) along a transect across the Gulf of Riga from the entrance to the Daugava River to the open Baltic are presented. Nutrient-limitation was identified on the basis of available nutrient concentrations and stoichiometric analysis. In spring, phosphate appeared to be the algal-growth-potential-limiting nutrient at the entrance of the Daugava River, DSi in the central Gulf, and DIN at the …

Forecasted changes in the climate and the river runoff regime in Latvian river basins

2012

The hydrological model HBV (Hydrologiska Byråns Vattenbalansavdelning model) has been applied to six river basins in Latvia to assess climate change and its impacts on the river runoff regime at the end of the 21st century. Climate change has been predicted by applying the regional climate model RCAO with the driving boundary conditions from the global general circulation model HadAM3H applied for the IPCC scenarios A2 and B2 and the following time periods: 1961–1990 (control) and 2071–2100 (scenario). Changes have been found under both scenarios. Major changes in the future hydro-climate data were forecasted according to the A2 scenario, where the trends of increase are identified for the …

Water quality modelling for ephemeral rivers: Model development and parameter assessment

2010

Summary River water quality models can be valuable tools for the assessment and management of receiving water body quality. However, such water quality models require accurate model calibration in order to specify model parameters. Reliable model calibration requires an extensive array of water quality data that are generally rare and resource-intensive, both economically and in terms of human resources, to collect. In the case of small rivers, such data are scarce due to the fact that these rivers are generally considered too insignificant, from a practical and economic viewpoint, to justify the investment of such considerable time and resources. As a consequence, the literature contains v…

Long-term changes in the water temperature of rivers in Latvia

2016

Abstract The study describes the trends of monthly mean water temperature (from May to October) and the annual maximum water temperature of the rivers in Latvia during the time period from 1945 to 2000. The results demonstrated that the mean water temperatures during the monitoring period from May to October were higher in the largest rivers (from 13.6 °C to 16.1 °C) compared to those in the smallest rivers (from 11.5 °C to 15.7 °C). Similar patterns were seen for the maximum water temperature: in large rivers from 22.9 °C to 25.7 °C, and in small rivers from 20.8 °C to 25.8 °C. Generally, lower water temperatures occurred in rivers with a high groundwater inflow rate, for example, in river…

Human-induced changes in the soil cover at the mouth of the Vistula River Cross-Cut (northern Poland)

2015

Celem badań było określenie wpływu działalności człowieka na powstawanie gleb w rejonie ujęcia Przekopu Wisły. Szczegółowe badania przeprowadzono na obszarze testowym (około 500 ha), dla którego została wykonana mapa gleb. Wydzielono trzy główne pasy grupujące gleby wytworzone z osadów morskich, eolicznych i technogenicznych, naturalnie i antropogenicznie zdeponowanych w wyniku regulacji hydrotechnicznych. Do dominujących gleb należą: gleby inicjalne, arenosole, glejowe,marsze i gleby industrialne, które charakteryzują się dużą zmiennością przestrzenną oraz występowaniem profili wieloczłonowych. Ich właściwości odzwierciedlają zróżnicowaną dynamikę środowiska w skali lokalnej po obu stronac…