Search results for "hydrology"
showing 10 items of 1041 documents
Nitrogen sedimentation in a lake affected by massive nitrogen inputs: autochthonous versus allochthonous effects
2006
12 pages, and tables statics, and figures
Effect of climate on surface flow along a climatological gradient in Israel: a field rainfall simulation approach
1998
Abstract A climatological gradient was selected in Israel to examine the effects of climate on surface flow and soil erosion. The gradient is composed of eight study areas located between the Dead Sea and the Galilee Mountains. Mean annual rainfall ranges from 100 mm year −1 in the driest site to 900 mm year −1 in the wettest site. Simulated rainfall experiments were performed in order to determine the main hydrological and erosional parameters. Data were recorded in 36 different plots after showers of 50 mm h −1 rain intensity and 45–60 min duration. In the arid sites ( −1 ) abundant runoff appeared on the soil surface very quickly, and the infiltration rates were very low. Erosion rates, …
Biohydrology: coupling biology and soil hydrology from pores to landscapes
2010
The articles in this issue are a selection of the presentations made at the 2nd International Conference of Biohydrology. This special issue ‘Biohydrology—coupling biology and soil hydrology from pores to landscapes’ contains a range of articles on biological and hydrological interactions in soil, including large-scale systems research on the influence of forests on catchments and small-scale reductionist research on processes operating at the scale of soil pores. Copyright 2010 John Wiley & Sons, Ltd.
Ecohydrological adaptation of soils following land abandonment in a semi-arid environment
2010
Representative land use types were selected in southeast Spain to investigate the redistribution of soil water in relation to vegetation development and land abandonment.Simulated rainfall experiments were performed during 2 days on each of the four selected surfaces: ploughed, a 3-year fallow field, a 12-year abandoned field with shrubs and a semi-natural field with Stipa tenacissima tussocks. Each experiment consisted of five runs of artificial rain. Soil moisture dynamics were measured by time domain reflectometry (TDR), as well as runoff and ponding on the plot surface. Also the movement of the wetting front was measured after each run.On the ploughed field, ponding and local runoff wer…
Application of the new multimetric MMI_PL index for biological water quality assessment in reference and human-impacted streams (Poland, the Slovak R…
2014
Abstract A new multimetric MMI_PL index, which is based on the macroinvertebrate composition and combines six single key metrics, has already been implemented in Poland according to the requirements of the EU Water Framework Directive. The objectives of our survey were to assess the biological water quality using the new multimetric MMI_PL index in both reference and human-impacted streams, to analyze whether the values of the new multimetric index properly reflect the ecological status of the water in upland and mountain streams as well as to determine which environmental factors influence the distribution of benthic macroinvertebrates and the values of the metrics. The study was carried o…
Effects of soil gas permeability and recirculation flux on soil CO2 flux measurements performed using a closed dynamic accumulation chamber
2009
Abstract Dynamic accumulation chamber methods have been extensively used to estimate the total output of CO2 released from active volcanic area. In order to asses the performance and reliability of a closed dynamic system several tests were carried out with different soil permeabilities and soil CO2 fluxes. A special device was used to create a constant one-dimensional CO2 flux through a soil column with a known permeability. Three permeabilities were investigated, ranging between 3.6 × 10− 2 and 3.5 × 10 μm2, as were several CO2 fluxes (ranging between 1.1 × 10− 6 and 6.3 × 10− 5 kg m− 2 s− 1). The results highlight that the accuracy of soil CO2 flux measurements strictly depends on the so…
Predicting event soil loss from bare plots at two Italian sites
2013
Abstract Including runoff in USLE-type empirical models is expected to improve plot soil loss prediction at the event temporal scale and literature yields encouraging signs of the possibility to simply estimate runoff at these spatial and temporal scales. The objective of this paper was to develop an estimating procedure of event soil loss from bare plots (length = 11–44 m, slope steepness = 14.9–16.0%) at two Italian sites, i.e. Masse, in Umbria, and Sparacia, in Sicily, having a similar sand content (5–7%) but different silt (33% at Sparacia, 59% at Masse) and clay (62% and 34%, respectively) contents. A test of alternative erosivity indices for the Masse station showed that the best perf…
Critical analysis of empirical ground heat flux equations on a cereal field using micrometeorological data
2009
The rate at which the net radiation is transferred to the soil as ground heat flux varies with surface characteristics. Surface energy balance algorithms use empirical relationships taking into account the effects of the canopy cover to insulate the soil through vegetation indexes, the soil capacity to absorb incoming net radiation via the albedo, and the surface temperature promoting the energy transfer. However empirical relationships are often dependent on local conditions, such as the soil humidity and vegetation type. Ground heat flux assumes a minimum value in case of full canopy cover and a maximum value for dry bare soil. Aim of the present research is the critical analysis of some …
Assessing crop coefficients of sunflower and canola using two-source energy balance and thermal radiometry
2014
Abstract A new technique for the local adjustments in crop coefficients is presented. This is an alternative to conventional lysimeter measurements traditionally used for improved irrigation scheduling. The method is based on the combination of a two-source energy balance model and local measurements of radiometric temperatures. Two experimental campaigns were carried out on sunflower and canola in a cropland area located in Barrax, Albacete, in the summer of 2011 and spring of 2012, respectively. Radiometric temperatures of soil and canopy were collected, together with biophysical and meteorological variables. Combining all these data in a two-source energy balance model allowed separation…
Discussion of “Discharge Characteristics of Weirs of Finite Crest Length with Upstream and Downstream Ramps” by Amir Hossein Azimi, Nallamuthu Rajara…
2014
C. Di Stefano; V. Ferro; and M. Bijankhan, Aff.M.ASCE Researcher, Dipartimento di Scienze Agrarie e Forestali, Universita degli Studi di Palermo, Viale delle Scienze, Palermo 90128, Italy. E-mail: costanza.distefano@unipa.it Full Professor, Dipartimento di Scienze Agrarie e Forestali, Universita degli Studi di Palermo, Viale delle Scienze, Palermo 90128, Italy (corresponding author). E-mail: vito.ferro@unipa.it Ph.D. Candidate, Irrigation and Reclamation Engineering Dept., Univ. of Teheran Karaj, P.O. Box 31587-4111, Karaj 31587-77871, Iran. E-mail: bijankhan@ut.ac.ir