Marengo H.,Comisión Federal de Electricidad |
Arreguin F.I.,Comision Nacional del Agua |
Romero I.,Comisión Federal de Electricidad
Tecnologia y Ciencias del Agua | Year: 2010
This article presents the procedure and application of several methods of risk and reliability analysis to a simple problem, such as the discharge capacity of a sewer. The analysis considers that the three variables of roughness, diameter, and slope have normal probability distributions and are applied for comparing direct integration methods; the Monte Carlo Method; Mellin Transform, with first-order variance estimation; Rosenblueth's and Harr's Point Estimation Method; the First Order Second Moment Method (MFOSM); and two versions of the Advanced First Order Second Moment Method (AFOSM): Hasofer-Lind's and Tang's. The result of the probability of failure obtained with the direct integration method is taken as true (which is not possible in complex analyses, especially when uncertainties are significant) and results are compared. Most methods can be applied, and it is possible to obtain reliable estimations when the methods come close to linear behaviors, but when the variables are not linear or when uncertainties increase significantly, the accuracy of some methods deteriorates rapidly. Such is the case of the MFOSM method. For methods with samples with sizeable variables, the Monte Carlo method is the most commonly applied, but the reliability of the method converges when there is a large number of simulations, and the final result of the probability of failure is strictly unknown; another important limitation is that the number of variables may cause the problem not to have a practical solution. Methods where point estimation is used (Rosenblueth and Harr) may be very attractive from a computational perspective in as much as the number of variables increases and may seem to be good to use, since they offer similar results to those obtained with the Monte Carlo method and the direct integration method. However, if uncertainties are significant, there may be meaningful differences. The MFOSM method is applicable only in very simple cases where the behavior function is clearly defined and there is variable linearity; however, it rapidly looses accuracy in complex problems. The MFOSM method is quite applicable and can take into account uncertainties in case the analyst decides to make correlations of the variables that intervene in the problem and that most of the times are associated with uncertainties. This seems to be a great advantage over the other methods, since it is possible to involve variables that are many times ignored or undervalued because they cannot be analyzed. The Hasofer Method seems to be quite appropriate for simple problems; however, the Tang Method is quite attractive for analyzing the failure limit state of the problem studied.
Arreguin-Cortes F.I.,Comision Nacional Del Agua |
Murillo-Fernandez R.,Comision Nacional Del Agua |
Marengo-Mogollon H.,Comisión Federal de Electricidad
Tecnologia y Ciencias del Agua | Year: 2013
Water infrastructure is a valuable national asset which makes it possible not only to make use of water resources but also to manage water courses to protect the population and conserve volume reserves during dry seasons or prolonged drought. This work presents information about storage works, control of courses and diversions in the country. It includes all of the dams registered in the national inventory, with over 20 years of documentation and direct site observations. This study also comments on the structural conditions and functioning of the dams.
Mejia-Gonzalez M.A.,Instituto Mexicano Of Tecnologia Del Agua |
Gonzalez-Hita L.,Instituto Mexicano Of Tecnologia Del Agua |
Briones-Gallardo R.,Autonomous University of San Luis Potosi |
Cardona-Benavides A.,Autonomous University of San Luis Potosi |
Soto-Navarro P.,Comision Nacional Del Agua
Tecnologia y Ciencias del Agua | Year: 2014
In order to elucidate the processes that causes high concentrations of arsenic in the aquifer of the Comarca Lagunera were conducted geochemical studies of groundwater and sediment. The results of the sediment geochemistry indicate that arsenic is mainly adsorbed on amorphous and crystalline Fe oxides. The results of the groundwater geochemistry indicate: 1) Cation Exchange between calcium and sodium, 2) Dissolution of calcite due to cation exchange, 3) Increase in pH due to the dissolution of calcite, and 4) high concentrations of arsenic due to elevated pH values.
Suarez-Medina M.D.L.A.,Instituto Mexicano Of Tecnologia Del Agua |
Patino-Gomez C.,Universidad de Las Americas Puebla |
Velazquez-Alvarez J.,Instituto Mexicano Of Tecnologia Del Agua |
Rivera-Benites J.,Instituto Mexicano Of Tecnologia Del Agua |
And 2 more authors.
Tecnologia y Ciencias del Agua | Year: 2015
The concept of geographic databases is currently being used to integrate spatial data and time series corresponding to water resources in a region. Geographic information systems (GIS), which are based on this concept, not only integrate both types of information into one database but also determine relationships among the information. The present study presents a GIS tool to estimate surface water availability based on the continuity equation, as established by Official Mexican Norm 011-CNA-2000 "Conservation of Water Resources - Establishment of Specifications and the Method to Determine National Annual Mean Availability of Water," published in the Official Journal of the Federation, April 17, 2002. Therefore, a geographic database of the ArcHydro data model needs to be generated, which applies mathematic models and stores information about the water resources, monitoring points and historical data in a hydrological basin. The advantages are the centralization of information and reducing the inconveniences involved in using different formats. © 2015 Tecnología y Ciencias del Agua.
Cuenca-Castro A.J.,Comision Nacional Del Agua |
Cardoso-Landa G.,Chilpancingo Institute of Technology
Dam Maintenance and Rehabilitation II - Proceedings of the 2nd International Congress on Dam Maintenance and Rehabilitation | Year: 2011
The present paper focuses on research possible causes of deterioration processes the curtain of land dam "El Batan" in Querétaro, Mexico, including the design of the fineness of the employee filter during the construction of the curtain was verified since this depends greatly on the proper functioning of this filter. To carry out the required analysis, it was necessary to document elements provided understanding about the composition and behavior of the land curtain, and the main types of failure in these curtains. The general characteristics of the land dam curtain "El Batan", the composition of the filter, as well as possible causes resulted in the failure were also analyzed. Once obtained data starting, the actual analysis was carried out by reviewing the following possible deterioration processes: fails due to a poor constructive process of the curtain, failure due to hydraulic suppression, fails due to a structural design wrong, fails due to a geotechnical design wrong, fails due to a hydraulic design wrong, fails due to an inadequate design of the curtain filter. It is concluded that the type of the filter employed in the land dam curtain of "El Batan", located in the municipality of Querétaro, México, do not have adequate characteristics, outside of the ranges of design, using the curves: Terzaghi criteria, Sherard and Dunnigan criteria, UCSCS criteria, and Foster and Fell criteria. © 2011 Taylor & Francis Group, London.
Alcocer-Yamanaka V.H.,Mexican Institute of Water Technology |
Tzatchkov V.G.,Mexican Institute of Water Technology |
Arreguin-Cortes F.I.,Comision Nacional del Agua
Water Resources Management | Year: 2012
Residential water demand is one of the most difficult parameters to determine when modeling drinking water distribution networks. It has been proven to be a stochastic process that can be characterized as a series of rectangular pulses with a set intensity, duration and frequency. These parameters can be determined using stochastic models such as the Neyman-Scott Rectangular Pulse (NSRP) model. The NSRP model is based on the solution of a non-linear optimization problem. This solution involves theoretical moments that represent the synthetic demand series (equiprobable) and the observed moments (field measurements) that statistically establish the measured demand series. The NSRP model has been applied for residential demand, and the results have been published. However, this model has not been validated for a real distribution network or compared with traditional methods. The present study compared the results of synthetic stochastic demand series, which were calculated using the NSRP model, applied to the determination of pressures, flow rates and leaks; to the results obtained using traditional simulation methods, which use the curve of hourly variation in demand, and to actual pressure and flow rate measurements. The Humaya sector of Culiacan, Sinaloa, Mexico, was used as the study area. © Springer Science+Business Media B.V. 2012.
Rivera-Trejo F.,Juarez Autonomous University of Tabasco |
Uh-Us F.,Comision Nacional del Agua |
Soto-Cortes G.,Metropolitan Autonomous University |
Diaz-Flores L.L.,Juarez Autonomous University of Tabasco
Tecnologia y Ciencias del Agua | Year: 2013
River studies generally begin with field inspection visits in order to collect information. Nevertheless, these visits often need to be repeated because there is not enough data, its quality is poor, the right tools are not available to properly collect them or some data are omitted for lack of clarity about what is needed. In practice, an increase in the number of visits is not desirable. It increases costs and external factors also exist that make additional visits impossible (for example, access has been changed or the conditions to be analyzed no longer exist). This paper proposes a methodological field survey guide to study rivers and hydraulics in such a way that ensures gathering the greatest amount and the best quality information as possible in one visit. An example of the application of the implementation of the guide is shown in a 10 km section of the Hondo River, located on the outskirts of the city of Chetumal, Quintana Roo, Mexico. The guide itself does not provide classifications or evaluations of the channel, but rather the elements needed to achieve these objectives. This guide is considered useful for engineers, technicians and river specialists wishing to undertake field studies, or for agencies such as Conagua, the CFE, state and federal governments, as well as universities and institutes involved in the maintenance, conservation, evaluation and management of rivers.
Arreguin Cortes F.I.,Comision Nacional del Agua |
Lopez Perez M.,Comision Nacional del Agua |
Angeles F.R.,Comision Nacional del Agua
Drought: Research and Science-Policy Interfacing - Proceedings of the International Conference on Drought: Research and Science-Policy Interfacing | Year: 2015
Since 2013, the Government of Mexico began the implementation of the National Drought Policy, changing the paradigm for drought management. Its main objective is reducing vulnerability through the implementation of actions planned under a preventive, holistic and participatory approach. Its fundamental elements are drought monitoring and alert on a fortnightly basis, the formulation and implementation of a Preventive and Mitigation Measures Programme for Drought for each Basin Council, a research program, a training program, the creation of technical and operative staff to coordinate drought response, a communication strategy and securing water supply to impacted populations. The creation of a Commission for the attention of droughts and floods gives the institutional and budgetary viability to the implementation of the policy. The shift to a proactive drought management is difficult and requires time to consolidate, however, given the historical background of Mexico and the effects of climate change, it is indispensable. © 2015 Taylor & Francis Group, London, UK.
Lomeli R.,Instituto Mexicano Of Tecnologia Del Agua |
Alvarez N.,Comision Nacional del Agua
WIT Transactions on Ecology and the Environment | Year: 2011
The surface dedicated to agriculture in Mexico is of approximately 21 million hectares, of which 6.4 million count as irrigation infrastructure, and 3.5 million (54%) correspond to 86 great areas called Irrigation Districts. The irrigated farming generates more than half of the national agricultural production. One of the main problems of the infrastructure maintenance is the accumulation of sediments in the distribution and drainage networks, caused fundamentally by insufficient actions of soils and water conservation in the basins of the irrigation dams. The present work analyzes the impact of the catchment basins degradation in the accumulation of sediments in the Irrigation Districts. © 2011 WIT Press.
De Jesus A.,National Autonomous University of Mexico |
Brena-Naranjo J.A.,National Autonomous University of Mexico |
Pedrozo-Acuna A.,National Autonomous University of Mexico |
Yamanaka V.H.A.,Comision Nacional del Agua
Water (Switzerland) | Year: 2016
Drought has been a recurrent phenomenon in Mexico. For its assessment and monitoring, several studies have monitored meteorological droughts using standardized indices of precipitation deficits. Such conventional studies have mostly relied on rain gauge-based measurements, with the main limitation being the scarcity of rain gauge spatial coverage. This issue does not allow a robust spatial characterization of drought. A recent alternative for monitoring purposes can be found in satellite-based remote sensing of meteorological variables. The main objective of this study is to evaluate the standardized precipitation index (SPI) in Mexico during the period 1998 to 2013, using the Tropical Rainfall Measuring Mission (TRMM) satellite product 3B42. Results suggest that Mexico experienced the driest conditions during the great drought between 2011 and 2012; however, temporal variability in the SPI was found across different climatic regions. Nevertheless, a comparison of the SPI derived by TRMM against the rain gauge-based SPI computed by the official Mexican Drought Monitor showed low to medium correlation of the time series though both SPIs managed to capture the most relevant droughts at the national scale. We conclude that the TRMM product can properly monitor meteorological droughts despite its relative short dataset length (~15 years). Finally, we recommend an assimilation of rain gauge and satellite-based precipitation data to provide more robust estimates of meteorological drought severity. © 2016 by the authors.