Phenomenological model of the intensity, duration and frequency of precipitation patterns for the Portoviejo river basin, Ecuador

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Introduction Methods and models have been developed to assess the parameters involved in the formation of surface runoff.1 In accordance with the generality of the hydrological cycle, all moisture that reaches the clouds and falls to the ground in the form of snowfall, rain, hail, thaw, etc., is involved in the formation of runoff. However, there is a hydrographic basin in Ecuador, the Manabí Hydrographic Demarcation, which is distinguished from the others, because its fluvial regime is formed exclusively by rainfall in the rainy season, which generally begins in December and ends in June [1; 2]. service soils. United States Department of Agriculture; 2015. Available from http://www.nrcs.usda.gov/ (accessed: 03.03.2015). Considering these particularities, to improve, with data updated to the year 20192, the models of Intensity-Duration-Frequency curves for the meteorological stations located in the Portoviejo River basin, this research work has been developed. in which new equations are provided for the estimation of rain intensities of return periods and different durations. The methods used in the analysis of the stochastic variables of precipitation are based on statistical and probabilistic methods developed throughout the history of earth sciences [3], among which the following stand out: methods of filling data missing from averages, regression line and orthogonal correlation accompanied by the respective data consistency analysis. For the frequency analysis, the data was subjected to the treatment with the Karl Pearson Type III correlation [4-6], where with the 3 moments and with the help of the Foster - Rybkin tables it was possible to estimate the extraordinary events for probabilities between 0.01 to 99.99%. To obtain the rainfall intensity equations, the method of least squares was used, where the intensities for rainfall durations corresponding to 0, 15, 30, 45, 60, 90 and 120 minutes were processed. 1. Materials and methods The basic information used for the analysis and development of the research is composed of the pluviometric records of maximum rainfall in 24 hours recorded at the Portoviejo-UTM meteorological stations (Portoviejo (M005) and Lodana (M298) for the period 1964-2019. These Data were provided by the National Institute of Meteorology and Hydrology (INAMHI) The total number of records used amounts to 1104. The meteorological stations of the study are in the Portoviejo River basin, which correspond to the Portoviejo-UTM stations, with code MO005, located in the vicinity of the Botanical Garden of the Technical University of Manabí, at coordinates 559523.22 E, 9884982.27N; and the Lodana station, with code MO298, located at coordinates 568606.76 E, 9871040.58N (Figure 1). To carry out this research, the experience offered by the National Institute of Meteorology and tense rains carried out in 1999 with its update in 2015 was taken as a starting point, and that, between others, presented a series of equations for estimating rainfall intensities for the entire national territory based on geographic location, duration of storms and specific return periods. The present work intends to be a complement to the methods that are currently used for the estimation of rainfall intensities, very useful when calculating runoff, product of rainwater drainage [9; 10]. The records used are updated and consistent and correspond to the period 1964-2019. The most relevant methodological aspects are inscribed in: a) selection of the meteorological stations;4 b) collection of the required information; c) analysis of data consistency; d) filling in missing data in the series [11]; e) variability analysis; f) preparation of the probability curve5 [12]; g) estimation of rainfall intensities [3]; and h) obtaining the intensity - duration - frequency (IDF) curves. Based on the values of maximum precipitation in 24 hours, obtained with the Pearson Type III distribution analysis, the weighted values of precipitation were obtained in accordance with the distribution of daily precipitation obtained in the hydrological studies of the basins of the Chone and Portoviejo rivers. This served as the basis for obtaining rainfall intensities for specific return periods. The functionality for estimating the events corresponding to various return periods contemplated by the Pearson Type 3 methodology is indicated in the formula:

About the authors

Junior Orlando Mendoza Alava

Technical University of Manabí

Email: jmendoza7865@utm.edu.ec
ORCID iD: 0000-0002-0395-6927

Associate Professor

Av. Urbina y Che Guevara, 130105, Portoviejo, Republic of Ecuador

Valencia Zambrano Xavier Horacioa

Technical University of Manabí

Email: xaviervalenciazambrano@gmail.com
ORCID iD: 0000-0002-1948-1161

master, engineer, Faculty of Sciences, Mathematics, Physics and Chemistry

Av. Urbina y Che Guevara, 130105, Portoviejo, Republic of Ecuador

Jorge J. Mendoza Cedeño

Technical University of Manabí

Email: jmendoza7865@utm.edu.ec
ORCID iD: 0000-0002-0567-451X

Associate Professor

Av. Urbina y Che Guevara, 130105, Portoviejo, Republic of Ecuador

Evgeny K. Sinichenko

Peoples’ Friendship University of Russia (RUDN University)

Author for correspondence.
Email: sinichenko-ek@rudn.ru
ORCID iD: 0000-0002-9159-1218

Ph.D., Associate Professor of the Department of Civil Engineering, Academy of Engineering

6 Miklukho-Maklaya St, Moscow, 117198, Russian Federation

Ilja I. Gritsuk

Peoples’ Friendship University of Russia (RUDN University); Water Problems Institute, Russian Academy of Sciences; Moscow Automobile and Road Construction State Technical University

Email: gritsuk-ii@rudn.ru
ORCID iD: 0000-0002-5671-7620

Associate Professor of the Department of Civil Engineering, Academy of Engineering, Peoples’ Friendship University of Russia (RUDN University); senior researcher, Laboratory of Channel Flow Dynamics and Ice-Thermics, Water Problems Institute, Russian Academy of Sciences; Associate Professor of the Hydraulic Department, Moscow Automobile and Road Construction State Technical University

6 Miklukho-Maklaya St, Moscow, 117198, Russian Federation; 3 Gubkina St, Moscow, 119333, Russian Federation; 64, Leningradskii Prospekt, Moscow, 125319, Russian Federation

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