Browsing by Author "Gonzalez-Leiva, Fernando"

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    A Rainfall Intensity Data Rescue Initiative for Central Chile Utilizing a Pluviograph Strip Charts Reader (PSCR)
    (2020) Pizarro-Tapia, Roberto; Gonzalez-Leiva, Fernando; Valdes-Pineda, Rodrigo; Ingram, Ben; Sanguesa, Claudia; Vallejos, Carlos
    To develop intensity-duration-frequency (IDF) curves, it is necessary to calculate annual maximum rainfall intensities for different durations. Traditionally, these intensities have been calculated from the analysis of traces recorded by rain gauges on pluviograph strip charts (PSCs). For many years, these charts have been recorded and analyzed by the personnel who operate and maintain the pluviograph gauges, thus the reliability of the observational analysis depends exclusively on the professional experience of the person performing the analysis. Traditionally, the analyzed PSCs are physically stored in data repository centers. After storing rainfall data on aging paper for many years, the risk of losing rainfall records is very high. Therefore, the conversion of PSC records to digital format is crucial to preserve and improve the historical instrumental data base of these records. We conducted the first "Data Rescue Initiative" (DRI) for central Chile using a pluviograph strip charts reader (PSCR), a tool that uses a scanner-type device combined with digital image processing techniques to estimate maximum rainfall intensities for different durations for each paper band (>80,000 paper bands). On the paper bands, common irregularities associated with excess ink, annotations, or blemishes can affect the scanning process; this system was designed with a semi-automatic module that allows users to edit the detected trace to improve the recognition of the data from each PSC. The PSCR's semi-automatic characteristics were designed to read many PSCs in a short period of time. The tool also allows for the calculation of rainfall intensities in durations ranging between 15 min to 1 h. This capability improves the value of the data for water infrastructure design, since intense storms of shorter duration often have greater impacts than longer but less intense storms. In this study, the validation of the PSCR against records obtained from observational analysis showed no significant differences between maximum rainfall intensities for durations of 1 h, 6 h, and 24 h.
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    HOURLY STREAMFLOW FORECASTING FOR THE HUAYNAMOTA RIVER, NAYARIT, MEXICO, USING THE DISCRETE KALMAN FILTER
    (2020) Alvarado-Hernandez, Leticia; Ibanez-Castillo, Laura A.; Ruiz-Garcia, Agustin; Gonzalez-Leiva, Fernando; Vazquez-Pena, Mario A.
    Because of extreme rainfall events caused by climate change and of accelerated alteration of basins by population growth, it is important to forecast streamflow generated by precipitation events. The objective of this study was to predict hourly flows in the Huaynamota River basin using the Discrete Kalman Filter (DKF), together with the autoregressive exogenous input model (ARX). Initially, the Kalman filter parameters are defined then recalculated for defined periods; that is, the model parameter values are constantly updated. Flows were forecasted six steps ahead (L=1, 2, 3, 4, 5 and 6 hours). The basin studied is part of the Huynamota River, delimited by the Chapalangana hydrometric station, upstream from the Aguamilpa reservoir, Nayarit, Mexico. The Huaynamota River is a tributary of the Santiago River. Hourly data series were used for precipitation and flow from August to September 2017. The DKF-ARX forecasting model showed Nash-Sutcliffe efficiency indexes between 0.99 and 0.85, with L=1 and L=6, respectively. It is concluded that it is feasible to obtain a good forecast of hourly streamflow with the discrete Kalman filter.