Ramón Domínguez-Mora

Failure of a drainage tunnel caused by an entrapped air pocket

A severe storm event occurred over the western area of Mexico City causing the rupture of a drainage tunnel, resulting in surface flooding, severe infrastructure damage and three deaths. This paper describes the methodology followed in order to validate the diagnostic of the event. The detailed investigation comprised in situ observation of the system, as well as hydraulic and structural analyses. In this case, severe pressure oscillations inside the tunnel caused by rapid filling and sudden air leakage through a large orifice (manhole) were recognized as the direct cause of the conduit burst. Further, the low strength of the concrete pipes of the tunnel, constructed without reinforced steel, and the low confinement by the dead load due to the soil above the tunnel also contributed to the rupture. The numerical results show a very unfavorable stress distribution along the tunnel stretch where the accident occurred, sufficient to cause the rupture.

Storms generator method that preserves their historical statistical characteristics. Application to Mexico City basin daily rainfall fields

A first procedure to generate synthetic storms, which preserves the statistical characteristics of the historical daily precipitation events registered in 49 stations located within the basin of Mexico City is presented. This procedure (a variation of the Svanidze method) implicitly supposes that the correlation between the maximum rainfall and its spatial distribution is meaningless. However, the obtained results did not validate that hypothesis. For this reason a second procedure was developed, which allows to consider the correlation between maximum rainfall and spatial distribution. This second procedure allowed reproducing the statistical characteristics of the daily rainfall for each station and also its spatial distribution, as shown in this work.

Influence of Guiding Curves in the Optimal Management of a Hydropower System

Optimal operating policies for hydropower generation in a system of dams were obtained by means of a modified algorithm of stochastic dynamic programming that incorporates the guiding curve concept and other operating requirements defined by the Mexican agency in charge of electricity generation. These operating policies were used to simulate the long term system behavior and to analyze the influence of the guiding curves in the energy generation, the volume spilled and the possible deficit. The results show that by trying different curves it is possible to obtain a range of results that will enable decision makers to choose those that best fit their needs.

Time and spatial synthetic hourly rainfall generation in the Basin of Mexico

ABSTRACT A method based on daily rainfall disaggregation was applied to generate storm events with spatial and temporal distribution. Information recorded in 49 rain-gauges of a network located in the Basin of Mexico within the period from 1988 through 2006 was used. The proposed method has an easy implementation; it preserves properly the statistical characteristics of the historical storms and, as it is shown in this paper, can be utilized to estimate the statistical behaviour of the discharges in the main accesses to the drainage system; in combination with a rainfall-runoff model, allows testing of different alternatives for operation policies. As an example, we obtained the statistics of the areal reduction factors for the synthetic generated storms.

SYNTHETIC GENERATION OF THE NORTH ATLANTIC OSCILLATION INDEX

In this article synthetic records of longer duration than the historic records of the North Atlantic Oscillation Index were compared. The synthetic records were obtained using the year interchange method and the Svanidze fragments method, as well as the Fiering method. These records can be used in simulation models for the longterm analysis of the behavior of the teleconnection index, predominantly vis-a-vis climate change scenarios.