Search results for "hydrology"
showing 10 items of 1041 documents
Micropollutants throughout an integrated urban drainage model: Sensitivity and uncertainty analysis
2017
Abstract The paper presents the sensitivity and uncertainty analysis of an integrated urban drainage model which includes micropollutants. Specifically, a bespoke integrated model developed in previous studies has been modified in order to include the micropollutant assessment (namely, sulfamethoxazole – SMX). The model takes into account also the interactions between the three components of the system: sewer system (SS), wastewater treatment plant (WWTP) and receiving water body (RWB). The analysis has been applied to an experimental catchment nearby Palermo (Italy): the Nocella catchment. Overall, five scenarios, each characterized by different uncertainty combinations of sub-systems (i.e…
Uncertainty in water quality modelling: The applicability of Variance Decomposition Approach
2010
Quantification of uncertainty is of paramount interest in integrated urban drainage water quality modelling. Indeed, the assessment of the reliability of the results of complex water quality models is crucial in understanding their significance. However, the state of knowledge regarding uncertainties in urban drainage models is poor. In the case of integrated urban drainage water quality models, due to the fact that integrated approaches are basically a cascade of sub-models (simulating the sewer system, wastewater treatment plant and receiving water body), uncertainty produced in one sub-model propagates to the following ones in a manner dependent on the model structure, the estimation of …
Modeling soil cation exchange capacity in multiple countries
2017
Abstract Cation exchange capacity (CEC), as an important indicator for soil quality, represents soil's ability to hold positively charged ions. We attempted to predict CEC using different statistical methods including monotone analysis of variance (MONANOVA), artificial neural networks (ANNs), principal components regressions (PCR), and particle swarm optimization (PSO) in order to compare the utility of these approaches and identify the best predictor. We analyzed 170 soil samples from four different nations (USA, Spain, Iran and Iraq) under three land uses (agriculture, pasture, and forest). Seventy percent of the samples (120 samples) were selected as the calibration set and the remainin…
Water Level Measurement Locations for Coastal Aquifer Management
2003
The coefficient of variation of the optimal cost (CVOC) method is applied to the Acqua dei Corsari coastal aquifer in Sicily's north coast to find the best point for a new water-level measurement location. The purpose of collecting data from the new measurement location is to reduce uncertainty associated with a stochastic management model for salt-water intrusion control. Assuming that uncertainty mainly stems from spatial variability of permeability, the structural parameters of the stochastic spatial permeability field are estimated using data from a nearby aquifer with similar geological properties. It is first shown through sensitivity analysis that the lack of previous information inh…
Climate changes' effects on vegetation water stress in Mediterranean areas
2010
Many recent studies have demonstrated that CO(2) increase is driving the climate in Mediterranean areas towards important changes, mainly represented by a temperature increase and a contemporaneous rainfall reduction. Starting from this premise, the primary aim of the present study is to investigate the effects of potential climatic changes on vegetational stress in Mediterranean ecosystems. Particular attention is here focussed only on the plants' water stress in water controlled ecosystems, mainly related to soil water balance. The interactions among climate, soil and vegetation are evaluated numerically by means of an ecohydrological model. In this work, different future climatic scenari…
Estimation of Mediterranean crops evapotranspiration by means of remote-sensing based models
2009
Abstract. Actual evapotranspiration from typical Mediterranean crops has been assessed in a Sicilian study area by using Surface Energy Balance and Agro-Hydrological models. Both modelling approaches require remotely sensed data to estimate evapotranspiration fluxes in a spatially distributed way. The first approach exploits visible (VIS), near-infrared (NIR) and thermal (TIR) observations to solve the surface energy balance equation. To this end two different schemes have been tested: the two-sources TSEB model, where soil and vegetation components of the surface energy balance are treated separately, and the widely used one-source SEBAL model, where soil and vegetation are considered as a…
The Impact of Climatic Change and Land Use on the Hydrological Response of Mediterranean Soils; a Study along a Climatological Gradient in Crete (Gre…
1995
Abstract To help understand the impact of Climatic Change on the soils of the Mediterranean area, measurements of physical soil properties were carried out in a mountain zone in Crete (Greece), following a climatological gradient. Four experimental slopes were chosen, south facing and situated on limestone lithology. Soil hydrological properties including infiltration, runoff and sediment concentration, were measured and the percentage of waterstable microaggregation in the soil was calculated and used as an indicator of soil degradation. It was found that as well as climate, soil properties were highly affected by the extensive land use of the area, intensive grazing by goats and small sca…
Soil erosion and hydrology of the western Mediterranean badlands throughout rainfall simulation experiments: A review
2013
Abstract Rainfall simulation experiments are widely used in geomorphological research in badland areas. This technique contributed significantly to our understanding of badland geomorphology in the Mediterranean belt. Due to the different types of simulated rainfall applied and the variable size of the plots a review of the State-of-the-Art is necessary. This study confirmed that rainfall simulations are well suited to (i) analyse runoff-infiltration processes and sediment detachment within badlands, and (ii) to establish the factors determining the hydrological and erosion response at interrill scale in badland areas. The hydrological response of badlands is characterized by rapid response…
Influence of vegetation recovery on soil hydrology and erodibility following fire: an 11-year investigation
2005
The present study investigates long-term changes in soil hydrological properties and erodibility during the regrowth of different types and densities of vegetation following a severe wildfire in the Serra Grossa Range, eastern Spain. Twelve plots of similar slope and soil characteristics, naturally recolonized by four different plant species (trees, herbs, shrubs and dwarf shrubs) were examined using rainfall simulations during an 11-year period. The mean erosion rate was 80 g m−2 h−1, 6 months after the fire under wet-winter conditions, declining to 30 g m−2 h−1 in the following summer and reaching <10 g m−2 h−1 after 2 years. Considerable variation under the different vegetation types …
Transient soil-moisture dynamics and climate change in Mediterranean ecosystems
2008
[1] Plants in Mediterranean ecosystems have developed different strategies to cope with transient soil-moisture dynamics induced by the markedly out of phase seasonal behavior of rainfall and temperature. Deep-rooted plants use the soil moisture stored in the wet winter (extensive users), while shallower rooted plants exploit both the wet season storage and the more sporadic growing season rainfall (intensive users). Using stochastic models of soil-moisture dynamics, we present an analytical and numerical description of the probabilistic structure of the soil-moisture storage at the beginning of the growing season in relation to the dynamics of the wet season and then study its evolution du…