Search results for "RUN"
showing 10 items of 2820 documents
Derivation of Rainfall Thresholds for Flash Flood Warning in a Sicilian Basin Using a Hydrological Model
2016
Abstract The damages caused by flash floods are among the most onerous in terms of loss of lives and damage to properties. Derivation of rainfall threshold is one of the approaches commonly used for the development of flash flood warning systems. Specifically, rainfall threshold is the rainfall amount that, for a given basin area and duration, is enough to cause flooding and, therefore, it indicates the maximal sustainable rainfall for a basin. The aim of this paper is deriving flash flood-rainfall thresholds for a Sicilian basin (Italy) throughout a deterministic approach. The conceptual hydrological model TOPDM was used to estimate the amount of rainfall that, for given duration, hydrolog…
Modifications in Water Resources Availability Under Climate Changes: A Case Study in a Sicilian Basin
2014
Climate variability due to the greenhouse effect has important implications on hydrological processes and water resources systems. Indeed, water availability, quality and streamflow are very sensitive to changes in temperature and precipitation regimes whose effects have to be fully considered in current water management and planning. International literature proposes several models, attempting to assess accurately the available water resources under stationary and changing climatic conditions at different spatial and temporal scales. In order to assess the potential impacts of climate change on surface and groundwater resources water availability in a Southern area of Italy, a conceptual h…
Soil hydrological response under simulated rainfall in the Dehesa land system (Extremadura, SW Spain) under drought conditions
1998
Soil hydrology was investigated in the Guadelperalon experimental watershed in order to determine the influence of land use and vegetation cover on runoff and infiltration within the Dehesa land system. Five soil–vegetation units were selected: (1) tree cover, (2) sheep trials, (3) shrub cover, (4) hillslope grass and (5) bottom grass. The results of the simulated rainfall experiments performed at an intensity of 56·6 mm h−1 during one hour on plots of 0·25 m2, and the water drop penetration time test indicate the importance of water repellency in the Dehesa land system under drought conditions. Low infiltration rates (c. 9–44 mm h−1) were found everywhere except at shrub sites and in areas…
Empirical Investigation of Curve Number Method Parameters in the Mediterranean Area
2012
AbstractThe curve number (CN) method is widely used as a technique for estimating surface runoff depth from rainstorms. This simply lumped method is based on the main parameter CN, which represents the lumped expression of basin absorption, and on a parameter that represents interception, infiltration during the early part of a storm, and surface depression storage, called initial abstraction. In this paper, CN is evaluated at the basin scale from rainfall-runoff multiday events, in the observation period 1940–1997 (recorded length mean equal to 20 years) for 61 Sicilian basins with three different methods: NEH4 method, asymptotic fitting method, and a least-squares method. A first analysis…
tRIBS-Erosion: A parsimonious physically-based model for studying catchment hydro-geomorphic response
2012
Our goal is to develop a model capable to discern the response of a watershed to different erosion mechanisms. We propose a framework that integrates a geomorphic component into the physically-based and spatially distributed TIN-based Real-time Integrated Basin Simulator (tRIBS) model. The coupled model simulates main erosive processes of hillslopes (raindrop impact detachment, overland flow entrainment, and diffusive processes) and channel (erosion and deposition due to the action of water flow). In addition to the spatially distributed, dynamic hydrologic variables, the model computes the sediment transport discharge and changes in elevation, which feedback to hydrological dynamics throug…
Effects of initialization on response of a fully-distributed hydrologic model
2008
Summary Knowledge of initial conditions is very important to correctly model the basin response at the storm event scale. Of particular interest is the influence of topography and soil type on the principal hydrologic variables and runoff generation mechanisms as a function of antecedent wetness conditions. This study addresses the influence of initial states on the short-term hydrologic response and characterizes the effects of topography and soils on the dissipation of the influence of the initialization conditions. Two case studies are considered: a synthetic two-dimensional planar hillslope with various assumed slope magnitudes and soil types; and a real basin (∼800 km2) with actual lan…
Impact of catchment properties on aquatic chemistry in the rivers of Latvia
2010
The relationships between land use characteristics and aquatic chemistry (nutrient concentrations, major inorganic ions and indicators of organic matter concentrations) were analyzed to determine factors controlling the runoff of dissolved substances, spatial variability of water chemical composition and possible impacts of pollution sources in Latvia. Groups of factors were found to determine the variability of nutrient, organic matter and major inorganic ions concentrations. Bedrock geology and weathering of soil minerals affect the concentrations of inorganic ions, but the nature of the relationships between nutrient concentrations and those of land use are good indicators of human impac…
Vulnerability of Mediterranean ecosystems to Climatic Change, study of soil degradation under different climatological conditions in an altitudinal t…
1995
Abstract To investigate the potential response of soils to climatic change, measurements of soil physical and chemical properties were carried out during a year in a mountain zone in Alicante (Spain), along an altitudinal and climatological gradient. Hydrological properties (infiltration runoff and sediment concentration) were measured under winter and summer conditions. Chemical and physical soil properties were analyzed for reference soil profiles along the transect. The erosional response of the soils as well as soil properties like organic matter and CEC are found to be under the direct influence of the climate, and as a result they have to be considered as important factors in the dese…
EHSM: a conceptual ecohydrological model for daily streamflow simulation
2013
A parsimonious conceptual lumped model is here presented with the aim of simulating daily streamflow in semi-arid areas. The model, processing daily rainfall and reference evapotranspiration at basin scale, reproduces surface and subsurface runoff, soil moisture dynamics, and actual evapotranspiration fluxes. The key elements of this numerical model are the soil bucket, where rainfall, evapotranspiration, and leakage drive soil moisture dynamics, and two linear reservoirs working in parallel with different characteristic response times. The surface reservoir, able to simulate the fast response of the basin, is fed by rain falling on impervious area and by runoff generated with excess of sat…
Apparent discrepancy in contamination history of a sub-tropical estuary evaluated through 210Pb profile and chronostratigraphical markers.
2005
Abstract Zn and Cd concentrations, stable lead isotopes and 210 Pb-derived chronology were determined in a sediment core sampled at Sepetiba Bay (South-eastern Brazil). During the last decades, the bay’s watershed has been modified by the increase of industrial activities and human interventions. In particular, Zn and Cd ore treatment plants were built near the coast in 1960 and 1970, respectively, and water has been diverted from the adjacent Paraiba do Sul River watershed since 1950. The core collected at shallow depth near the industrial area exhibits four successive events: (i) at 50 cm depth, a change in the 206 Pb/ 207 Pb ratio from about 1.162 to more than 1.18 might be the result of…