Search results for "hydrology"
showing 10 items of 1041 documents
Wastewater modification processes in a stabilization reservoir: a new mathematical model
2018
The paper presents a mathematical model for the simulation of the ecology of a wastewater stabilization reservoir (WSR). WSRs are hypertrophic aquatic systems devoted to water storage in warm countries where shortage conditions are often encountered. Several factors that affect the stabilization reservoir’s effluent quality were taken into account: hydraulics and hydrology, solar radiation, reaeration, algae, zooplankton, organic matter, pathogens, and sediment-water interactions. The model quantifies the specific influence of each factor on effluent quality, and evaluating the correlation between the different factors. State variables included in the model were: algae, dissolved oxygen, or…
Water residence time and the dynamics of toxic cyanobacteria
2012
SUMMARY 1. Climate change affects aquatic ecosystems differently depending on local conditions. In the Mediterranean region, predicted drier seasons could especially affect lake water residence time and in consequence cyanobacteria and cyanotoxin dynamics. 2. We carried out a 3-year study of a shallow, Mediterranean lake (Lake Albufera, Spain), to study the effects of water residence time and other drivers on the dynamics of harmful cyanobacteria and microcystin concentrations (MCYST). 3. Longer water residence time in dry years and dry seasons increased total cyanobacteria biomass, Microcystis aeruginosa populations and MCYST concentrations in the lake water and seston. Droughts increased …
Short-term spatio-temporal spring grassland fire effects on soil colour, organic matter and water repellency in Lithuania
2013
Abstract. The aim of this work was to study the short-term effects (first 9 months after the fire) of a low-severity spring boreal grassland fire on soil colour, soils organic matter (SOM) and soil water repellency (SWR) in Lithuania. Three days after the fire we designed a plot of 400 m2 in a control (unburned) and unburned area with the same geomorphological characteristics. Soil water repellency analysis were assessed through the 2 mm mesh (composite sample) and in the subsamples of all of the 250 samples divided into different soil aggregate fractions of 2–1, 1–0.5, 0.5–0.25 and < 0.25 mm, using the Water Drop Penetration Time (WDPT) method. The results showed that fire darkened the …
Climate change of Benin for the period 1950-2010 and its impact on surface water.
2016
6 pages; International audience; In West Africaand Benin in particular, variability / climate change affects the availability of surface water resources. Thus,this study aims to analyze the rainfall field of Benin from the fifty three (53) meteorological stations from 1950to 2010 and to detect the rainfall amounts and the average temperature of six synoptic stations and thehydrometric stations of Niger river in, Benin, Pendjari, Ouémé, Mono and Couffo. From the analysis a trend ofdeclining precipitation and of rising temperatures have been highlighted. This decrease is more pronounced inthe Sudanese area (north of 8 ° N) and in the sub-equatorial area (south of 8 ° N). This decrease of prec…
Assessment of climate impacts on hydrology and geomorphology of semiarid headwater basins using a physically-based model.
2013
The response of watershed erosion rates to changes in climate is expected to be highly non-linear and thus demands for mechanistic approaches to improve our understanding of the underlying causes. In this study, the integrated geomorphic component tRIBS-Erosion of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time Integrated Basin Simulator, is used to analyze the sensitivity of small semi-arid headwater basins to projected climate conditions. Observed historic climate and downscaled realizations of general circulation models from CMIP3 inform the stochastic weather generator AWE-GEN (Advanced WEather GENerator), which is used to produce two clima…
Multivariate statistical analysis of heavy metals and physico-chemical parameters in the groundwater of Karak District, Khyber Pakhtunkhwa, Pakistan
2021
Groundwater heavy metal pollution is a major concern all around the world. For the assessment of heavy metals and physico-chemical characteristics. groundwater samples were collected from different locations of the Karak District, Pakistan. With the help of the global information system device (GIS), groundwater samples were collected and studied from 47 locations. The present study focused on the water table (WT), water source depth (WSD), pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), lead (Pb(II)), silver (Ag(I)), iron (Fe(II)) and chromium (Cr(VI)) parameters. Heavy metals were analyzed by the Atomic Absorption Spectrophotometer (AAS). The Pearson…
Application d’un modèle conceptuel à l’analyse de la dynamique hydrométéorologique des crues dans un bassin-versant en milieu tropical humide : cas d…
2015
7 pages; International audience; Application of a conceptual model to analysis of dynamic hydrometeorological flood in a pool - side in tropicalmoist environment : the case of Mono river. The objective of this study is to analyze the dynamics of the basinhydrometeorological and distribution of incoming flood dam Nangbéto to assess the risk of flooding in the lower valley of theriver. The data used are: daily flows of Mono (m3.s-1) and Nangbéto Athiémé, evapotranspiration (mm / day, calculatedaccording to the method Oudin et al., 2005) and the average precipitation over the basin (mm / day) covering the period1988- 2010. The method of spatial interpolation of rainfall tested is that of ordin…
Standard Asymptotic Response and Expected Runoff from Curve Number Theory
2015
The Standard Asymptotic response is a common finding with rainfall-runoff analysis with the Curve Number method. Widely-observed in data analyses, it is the secondary relationship between the data-defined CN and the causative rainfall P, for which the empirical fitting equation CN(P) = CN∞+ (100-CN∞)exp(-kP) has been found to fit well. This is an unexpected variation in the handbook methodology. It is investigated here on a “theoretical” basis by using the handbook tabled values of CN for the three AMC classes, I, II, and III; the storm-to-storm S (=1000/CN-10); and the observed 12-50-88 percent conditional probabilities for the ARC classes. With this, and treating S as a variable across th…
WATER MASSES EXCHANGE THROUGH THE STRAIT OF SICILY DURING THE LAST DEGLACIAL PERIOD AND THE HOLOCENE
2022
The main goal of this thesis is to explore the inter-basin connection between the eastern and the western Mediterranean (E- and W-Med, respectively) during the last deglacial and Holocene periods (last 15 kyr). The thesis is based on the study of a sediment core recovered at the west flank of Sicily channel (W-Sicily), strategically located under the current path of the surface Atlantic waters and directly below the present-day hydrographic boundary layer between the Eastern Mediterranean Sourced Water (EMSW) and the Western Mediterranean Deep Water (WMDW). This key location allow to explore past changes in both surface and deep water exchange between the E and the W-Med. In this thesis, a …
Deducing the stage-discharge relationship for contracted weirs by the outflow theory of Malcherek
2019
The aim of this paper was the deduction of a new stage-discharge relationship for a contracted weir, having a crest length less than the channel width, by using the Malcherek’s outflow theory. The average outflow velocity over the rectangular contracted weir was expressed in terms of the head over weir, the momentum correction coefficient and the ratio between the crest length and the channel width. This theoretically deduced stage-discharge formula was calibrated by measurements carried out for values of the ratio between the crest length and the channel width ranging from 0.3125 to 0.9375. In particular, a relationship to estimate the momentum correction coefficient for contracted weirs w…