Search results for "Runoff"
showing 10 items of 294 documents
Impact of rainfall data resolution in time and space on the urban flooding evaluation
2012
ABSTRACT Climate change and the modification of urban environment increase the frequency and the impact of flooding rising the interest of researchers and practitioners on this topic. Usually flooding frequency analysis in urban areas are indirectly carried out by adopting advanced hydraulic models to simulate long historical rainfall series or design storms. However their results are affected by a grade of uncertainty which has been much investigated in recent years. One of the most critical source of uncertainty inherent to hydraulic model results is linked to the imperfect knowledge of the rainfall input data both in time and space. Several studies show that hydrological modelling in urb…
Pinus halepensis M. versus Quercus ilex subsp. Rotundifolia L. runoff and soil erosion at pedon scale under natural rainfall in Eastern Spain three d…
2017
Abstract Afforestation aims to recover the vegetation cover, and restore natural ecosystems. The plant species selected for restoration will determine species richness and the fate of the ecosystem. Research focussing on the impact of vegetation recovery on soil quality are abundant, especially on fire affected land and where rehabilitation, afforestation and restoration projects were carried out. However, little is known about how different plants species affect soil erosion and water losses, which are key factors that will impact the fate of the afforested land. Aleppo pine (Pinus halepensis M.) is the species commonly used for afforestation in the Mediterranean and is very successful whe…
The green roofs for reduction in the load on rainwater drainage in highly urbanised areas
2021
AbstractRapid weather phenomena, particularly sudden and intense rainfall, have become a problem in urban areas in recent years. During heavy rainfall, urban rainwater drainage systems are unable to discharge huge amounts of runoff into collecting reservoirs, which usually results in local flooding. This paper presents attempts to forecast a reduction in the load on the rainwater drainage system through the implementation of green roofs in a case study covering two selected districts of Opole (Poland)—the Old Town and the City Centre. Model tests of extensive and intensive roofs were carried out, in order to determine the reduction of rainwater runoff from the roof surface for the site unde…
Derivation of a Distributed Unit Hydrograph Integrating GIS and Remote Sensing
2007
The paper describes the results of a study based on the integration of remote sensing and geographical information system techniques to evaluate a distributed unit hydrograph model linked to an excess rainfall model for estimating the streamflow response at the outlet of a watershed. Travel time computation, based on the definition of a distributed unit hydrograph, has been performed, implementing a procedure using (1) a cell-to-cell flow path through the landscape determined from a digital elevation model (DEM); and (2) roughness parameters obtained from remote sensing data. This procedure allows the taking into account of the differences, in terms of velocity, between the hillslopes and t…
Rainfall and water yield in Macizo del Caroig, Eastern Iberian Peninsula. Event runoff at plot scale during a rare flash flood at the Barranco de Ben…
2021
[EN] Floods are a consequence of extreme rainfall events. Although surface runoff generation is the origin of discharge, flood research usually focuses on lowlands where the impact is higher. Runoff and sediment delivery at slope and pedon scale receiving much less attention in the effort to understand flood behaviour in time and space. This is especially relevant in areas where, due to climatic and hydrogeological conditions, streams are ephemeral, so-called dry rivers (¿wadis¿, "ramblas" or ¿barrancos¿) that are widespread throughout the Mediterranean. This paper researches the relationship between water delivery at pedon and slope scale with dry river floods in Macizo del Caroig, Eastern…
Influence of rating curve uncertainty on daily rainfall–runoff model predictions
2005
River discharge observations are usually affected by uncertainty, which is due to many concurrent causes and strongly affects the response of rainfall-runoff models. The present paper is aimed at studying the influence of imperfect rating curve knowledge on the uncertainty of the response of a daily conceptual linear-nonlinear rainfall-runoff model. To describe the impact of imperfect rating curve knowledge, simulations have been conducted using a conceptual rainfall-runoff model and continuous daily series of rainfall, air temperature and discharges recorded in a Sicilian catchment. The GLUE procedure was used to introduce the uncertainty of the rating curve in a classical rainfall-runoff …
La formula razionale rivisitata
2019
The Rational Formula (RF), also known as CIA formula, is probably the most applied equation in practical hydrology to compute the peak discharge, due to its simplicity and effective compromise between theory and data availability. The RF assumes the linearity of the hillslope response, neglects the time to ponding and the antecedent soil moisture condition (ASMC), concentrates the infiltration effect in the runoff coefficient (C) which estimation is highly controversial, since it is based on qualitative indications. This paper proposes an advanced rational formula that makes it possible to derive the peak discharge at the hillslope scale, where the above assumptions are relaxed and which de…
Assessing hydrological connectivity inside a soil by fast-field-cycling nuclear magnetic resonance relaxometry and its link to sediment delivery proc…
2017
Connectivity is a general concept used to represent the processes involving a transfer of matter among the elements of an environmental system. The expression “hydrological connectivity inside the soil” has been used here to indicate how spatial patterns inside the soil (i.e., the structural connectivity) interact with physical and chemical processes (i.e., the functional connectivity) in order to determine the subsurface flow (i.e., the water transfer), thereby explaining how sediment transport due to surface runoff (i.e., the soil particle transfer) can be affected. This paper explores the hydrological connectivity inside the soil (HCS) and its link to sediment delivery processes at the p…
Measuring hydrological connectivity inside soils with different texture by fast field cycling nuclear magnetic resonance relaxometry
2022
Abstract The locution “hydrological connectivity inside the soil” is generally used to disclose how the spatial patterns inside the soil affect the physical–chemical processes at a molecular level to influence water transfer into the soil, the surface runoff and related sediment transport. Fast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometry has been used to measure both structural and functional connectivity by two indexes indicated as structural (SCI) and functional (FCI) connectivity index. Here, FFC-NMR relaxometry has been applied to analyze three samples: two non-degraded soils, having different grain-size distribution, and a degraded soil sampled in a badland area. P…
Urban Stormwater Management, A Tool for Adapting to Climate Change: From Risk to Resource
2020
The effects of climate change on rainfall in the Mediterranean region are manifested in an overall decreasing trend, and greater irregularity in annual volumes and the city of Alicante is no exception. In addition, there has also been a spread of the urbanised area, which has led to an increase in the flood risk in urban areas (due to a greater runoff and the occupation of flood hazard areas) and drought events due to an increase in the water demand. In light of these new scenarios, the Mediterranean cities should design adaptation systems based on rainwater harvesting within the framework of a circular economy. This study analyses the integration of rainwater in flood and water demand mana…