Search results for "Runoff"
showing 10 items of 294 documents
Weathering of evaporites: natural versus anthropogenic signature on the composition of river waters
2015
Weathering of evaporites strongly influences the chemistry of continental runoff, making surface waters poorly exploitable for civil uses. In south-central Sicily, this phenomenon is worsened by the occurrence of abandoned landfills of old sulphur and salt mines. The industrial evolution of the Bosco-S. Cataldo mining site leaved two landfills from the early exploitation of a sulphur mine followed by that of a kainite deposit. In particular, the weathering of these landfills leads the dissolved salt (TDS) values up to about 200 g l−1 in the Stincone–Salito Stream waters. This process induces the V, Cr and Fe desorption from sediments and particulates in the aqueous phase under reducing cond…
Slope threshold for overland flow resistance on sandy soils
2021
Recent research on rill flows recognised that an 18% slope can be used to distinguish between ‘gentle’ and ‘steep’ slope cases for the detected differences in hydraulic (flow depth and velocity) and sediment transport variables (flow transport capacity, actual sediment load). The effects of slope on flow velocity, friction factor and transport capacity and their interactions affect process-based erosion modelling. The main aim of this paper is to investigate, for the first time, how slope affects the overland flow resistance on sandy soils, which are characterised by loose particles readily available to be transported and deposited. Using literature measurements carried out in sandy soils f…
Rainfall timing and runoff: The influence of the criterion for rain event separation
2016
Abstract Rain is not uniform in time and space in semiarid areas and its distribution is very important for the runoff process. Hydrological studies usually divide rainfall into events. However, defining rain events is complicated, and rain characteristics vary depending on how the events are delimited. Choosing a minimum inter-event time (MIT) is a commonly used criterion. Our hypothesis is that there will be an optimal MIT that explains the maximum part of the variance of the runoff, with time to runoff used as a surrogate. The objective is to establish a procedure in order to decide upon this optimal MIT. We developed regressions between time to runoff (T0) and three descriptive variable…
Biohydrology research after Landau 2013 conference
2014
Biohydrology gives a new view on hydrological research. The impact of biota on hydrological processes was a disregarded topic in the early years of hydrology research. It has been present since the 1960s, but as a „Cinderella“ research topic. It emerged as a new aspect of the hydrological processes after the 1980s. In the 21st century, it has become a well established research topic, bringing new knowledge to aid understanding on how biota influence the hydrological cycle and the rates of hydrological processes. The importance of biohydrology research is growing, and the number of conferences, publications and research projects is being doubled every decade. The 4th Biohydrology conference,…
The Use of GAMLSS Framework for a Non-Stationary Frequency Analysis of Annual Runoff Data over a Mediterranean Area
2022
Climate change affects all the components of the hydrological cycle. Starting from precipitation distribution, climate alterations have direct effects on both surface water and groundwater in terms of their quantity and quality. These effects lead to modifications in water availability for agriculture, ecology and other social uses. Change in rainfall patterns also affects the runoff of natural rivers. For this reason, studying runoff data according to classical hydrological approaches, i.e., statistical inference methods that exploit stationary probability distributions, might result in missing important information relevant to climate change. From this point of view, a new approach has to…
Simplified Model to Predict Runoff Generation Time for Well-Drained and Vegetated Soils
2016
The study of generation process of subsurface stormflow, typical of well-drained and high permeable soils, can be theoretically carried out by applying the continuity and the motion equations with the appropriate boundary conditions. However, difficulties and uncertainness on determining soil hydraulic properties and soil physics heterogeneities let this way not always feasible. In a different way, processes dynamic can be derived by the local scale through a coarse graining procedure, allowing to preserve medium motion character, while hydraulic fluctuation of the motion are lost. Following an approach as this, in this paper a simplified model to predict the runoff generation time, the so-…
Flash-flooding of Ephemeral Streams in the Context of Climate Change
2021
Ephemeral streams, which are more extended than expected, entail a significant flood risk. Historically they have been underestimated due to their intermittent flow and the lack of knowledge on their hydro-geomorphology. Currently, European legislation recognizes their associated risk and supports research into them, adapting the scale and methodology to their characteristics. Based on the compilation of various works carried out in four Valencian catchments (Eastern Spain), this paper approaches the key questions of rainfall-runoff conversion and flood generation in ephemeral streams, taking into account their hydro-geomorphological specificity. Moreover, the consequences which derive from…
Cambios en los usos del suelo y producción de escorrentía en ramblas mediterráneas: Carraixet y Poyo (1956-1998)
2007
Ana.Camarasa@uv.es Juan.Mateu@uv.es Este trabajo analiza el efecto de los cambios recientes en los usos del suelo en la génesis de escorrentía en ramblas mediterráneas utilizando un SIG. Para el cálculo de la producción de escorrentía se ha utilizado el método desarrollado por el S.C.S. modificado por Témez (1978) que combina los mapas de pendientes, usos del suelo y grupo hidrológico del suelo. Se ha aplicado una adaptación del método propuesta por Camarasa et al. (2006) basado en la interpretación hidrogeomorfológica de la cuenca para la estimación del grupo hidrológico de suelo. Los resultados muestran una variabilidad espacial y temporal importante en la dinámica de producción de escorr…
Soil moisture changes after land abandonment in the Central Spanish Pyrenees
2001
14 páginas, 3 tablas, 6 figuras.
A rational runoff coefficient for a revisited rational formula
2019
The Rational Formula (RF) is probably the most frequently applied equation in practical hydrology to compute the peak discharge, due to its simplicity and effective compromise between theory and data availability. Thus, after more than a century, the estimation of peak discharge through the RF is still an important and challenging issue in hydrology. The RF assumes response linearity and sometimes assumes that the return period does not depend on the runoff coefficient and neglects the time to ponding and the antecedent moisture condition. Moreover, the RF requires the critical duration of rainfall and the runoff coefficient to be estimated, both of which are highly controversial. This pape…