Search results for " Structural"
showing 10 items of 1751 documents
Crop Coefficient Curve for Paddy Rice from Residual Energy Balance Calculations
2017
AbstractThe crop coefficient (Kc) values of rice paddy are important for estimating accurate rice crop evapotranspiration (ETc), water transfers planning, efficient irrigation management, and hydrological studies. In this study, ETc was measured and a generalized Kc curve was calculated for paddy rice in the Sacramento Valley, California. Field experiments were conducted in three rice paddy fields during the 2011–2013 growing seasons. Surface renewal analysis, after calibration using eddy covariance method, was applied to obtain sensible heat flux values from high-frequency temperature readings; latent heat flux densities were characterized by the residual of the energy balance method. The …
SCS Curve Number and Green-Ampt Infiltration Models
2019
Soil Conservation Service curve number (SCS-CN) and Green-Ampt (GA) infiltration models are probably the most applied equations in practical hydrology to compute the amount of direct runoff from rainfall. Both models are very simple, require few parameters, and present drawbacks and advantages. The empirical CN model concentrates the infiltration effect in the curve number and in the so-called soil hydrological groups, which have been widely characterized for different soil types, land cover, and antecedent soil moisture conditions (ASMCs), although the latter was considered ambiguous, whereas soil hydrological characteristics, including ASMC, are taken into account for the simplified physi…
Probability Distribution of Peak Discharge at the Hillslope Scale Generated by Hortonian Runoff
2016
In this work, the probability distribution of peak discharge at the hillslope bottom is determined hypothesizing a prevalent Hortonian mechanism of runoff production for a given rainfall duration. As is well known, the probability distribution of peak discharge depends on the probability of both the rainfall event as well as that of the antecedent soil moisture conditions. In particular, the probability of the rainfall event is calculated according to the familiar rainfall duration-intensity-frequency approach, whereas the ecohydrological method from the literature is used here to define the probability of the antecedent soil moisture conditions. The latter depends on a set of parameters de…
Strategies investigation in using artificial neural network for landslide susceptibility mapping: application to a Sicilian catchment
2013
Susceptibility assessment of areas prone to landsliding remains one of the most useful approaches in landslide hazard analysis. The key point of such analysis is the correlation between the physical phenomenon and its triggering factors based on past observations. Many methods have been developed in the scientific literature to capture and model this correlation, usually within a geographic information system (GIS) framework. Among these, the use of neural networks, in particular the multi-layer perceptron (MLP) networks, has provided successful results. A successful application of the MLP method to a basin area requires the definition of different model strategies, such as the sample selec…
Overland Flow Times of Concentration for Hillslopes of Complex Topography
2016
The time of concentration is an important parameter for predicting peak discharge at the basin outlet and for designing urban infrastructure facilities. In studying the hillslope response, employing hydraulic equations of flow, the shape of the hillslope geometry has often been assumed as rectangular and planar. However, natural hillslopes have complex topographies whose shapes are characterized by irregularly spaced contour lines. Recently, kinematic wave time of concentration has been derived for rectangular and curved parallel hillslopes. This paper extends this work to hillslopes of complex planform geometry, considering the degree of divergence or convergence of the hillslope. The exte…
Experimental Modeling of Submerged Pivot Weir
2020
An inclined rectangular overflow structure, also called a pivot weir, consists of a rectangular plate, angled downstream from the vertical, that can be used as an upstream water level control device. A pivot weir is submerged when the upstream water level is influenced by the downstream flow depth. In this paper, to investigate factors influencing submerged flow conditions, an extensive experimental program including 251 experimental trials was carried out using weir inclination angles of 39.6°, 53°, 85°, and 90° and weir heights ranging from 0.263 to 0.312 m. A formula to distinguish between free and submerged flow conditions was developed using the Π theorem of dimensional analysis and th…
Screening Investments to Reduce the Risk of Hydrologic Failures in the Headwork System Supplying Apulia (Italy) – Role of Economic Evaluation and Ope…
2014
The paper introduces and applies a methodology to screen investments aimed at reducing water supply risks due to hydrologic failures in headwork systems for municipal use, based on the principles of cost-benefit analysis. As risk includes both the probability of a failure and its effect, the methodology combines a simulation module of the system, fed by a stochastic hydrologic input to reproduce the probability distribution of the failures, with a metric for supply failure damage provided by the price – demand relationship for municipal water. Benefits are assessed as the averted damage compared to a base case without investments. This approach is then combined with the classic discounted c…
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
Simulation of the operation of detention tanks.
2005
The performance of detention tanks with different characteristics (volume, on-line and off-line arrangement) has been evaluated according to the results of a continuous simulation. The conceptual simplified model for sewer system simulation (COSMOSS) model has been used to simulate the operation of the tanks. The differences between the performance of on-line and off-line tanks and the influence of the characteristics of different catchments have been examined. According to the results of the simulations detention tanks demonstrated good performances in total suspended solids retention and this evenience can certainly help to prevent water pollution of receiving water bodies in urban areas,…
Use of L-moments approach for regional flood frequency analysis in Sicily, Italy
2008
Extremely great floods are among environmental events with the most disastrous consequences for the entire world. Estimates of their return periods and design values are of great importance in hydrologic modeling, engineering practice for water resources and reservoirs design and management, planning for weather-related emergencies, etc. Regional flood frequency analysis resolves the problem of estimating the extreme flood events for catchments having short data records or ungauged catchments. This paper analyzes annual maximum peak flood discharge data recorded from more than 50 stream flow gauging sites in Sicily, Italy, in order to derive regional flood frequency curves. First these data…