A. A. Adegbola ¹, J. K. Jolayemi

Affiliations
1 Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso,

Abstract

Flooding in major cities like the city of Ibadan, the largest urban centre south of the Sahara, Africa, is a common phenomena. Flooding occurred in several areas of the city each time when Ogunpa River overflowed its banks. Flood damage mitigation measures were necessitated by increased runoff due to rapid urbanization of the catchment area coupled with inadequate runoff data along the river course. Ogunpa River gained its national and international notoriety when many lives and properties worth billions of Naira were lost in the floods of 1960, 1963, 1978, 1980 and 2011. This study was conducted at Queen Elizabeth gauging station to develop an historical rainfall-runoff model for River Ogunpa. The model developed was a linear regression approach considering the effects of previous and current rainfall on the flow of the effluent streams. Average daily net rainfall data and average daily rainfall were regressed against average daily runoff data. Using linear regression method Net rainfall values (R') and rainfall values (R) were regressed against the corresponding discharge (Q) arrived at correlation coefficients of 0.66975 and 0.71191989 respectively. Utilizing 101 years of rainfall records for Ibadan City, runoff data for Ogunpa River were derived. This data could serve as a veritable hydrologic input in the design of embankment flood mitigation structures for River Ogunpa. It is recommended that to find a lasting solution to the menacing frequent flooding more runoff gauging stations be provided along the river course of Ogunpa River within Ibadan metropolis.

Keywords

Rainfall run-off Model, River Ogunpa, Nigeria

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A. A. Adegbola ¹, O. A. Kumolu ¹

Affiliations
1 Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso, NG

Abstract

Omi river flows through Omi-Adio, Iddo Local Government Area (LGA) of Oyo State, Nigeria. The watershed hydrology of the river, over the years, has changed considerably due to the ever increasing anthropogenic activities. The resultant effect is the inundation of farmlands and flooding of residential areas in Omi-Adio township, whenever the river overflowed after heavy rain falls. Unfortunately, as with most Nigerian rivers, no discharge record exists for Omi river, making planning for provision of hydraulic structures difficult. One hundred and three years of available rainfall data and existing five years of discharge record for Ogunpa river at Molete grammar school were used to simulate surface runoff for Omi river, using average proportionality and linear regression methods. The approximation of data was based on established literature, which states that Omi and Ogunpa Rivers have similar geological and morphological characteristics. The simulation was validated with field measurements. The constant of proportionality between the two rivers was found to be 2.467. The constants: 'a' and 'b' in the linear regression equation for Omi River were computed to be 0.306445 and 0.0003036, respectively, with a correlation coefficient of 0.98876. The linear regression method was found to be more appropriate for Omi River at Omi Adio, Ibadan, when compared with field values. The study will assist in providing reasonable data in the design of hydraulic structures such as bridges, concrete channels, culverts and flood control structures for Omi-Adio LGA.

Keywords

Flooding, Hydrology, Watershed, Correlation, Calibration

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A. A. Adegbola ¹, M. J. Dada ¹

Affiliations
1 Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso

Abstract

The manual approach to concrete mix design requires understanding of the data in the British Department of Environment (DOE) Code. This often requires interpolations in determining intermediate values of variables for the concrete mix design, which is prone to human errors when tracing out, estimating and recording values. Mathematical equations for concrete mix design in accordance to the guidelines of DOE were derived as a replacement to the tabular data, figures and graphs in the DOE concrete mix design charts. Computer program was developed for the optimization of concrete mix designs. DOE data were converted to equations by developing mathematical models and selecting through optimization the most suitable relationship that adequately represented the data based on the regression coefficient values. The equations were converted to a developed computer program called CLETJER using Java Programming Language Version 7, with NETBINS Version 7.1 as the Integrated Development Environment (IDE). The developed Program, when executed and used for concrete mix design, was observed to a large extent, to reduce the computation time and energy which were inherent in the manual process. The developed Program, interfaced into ninety-seven (97) interactive user-friendly windows, is capable of determining the relative proportions and quantities of material constituents of concrete and making necessary adjustments to the mix design to suit the trial mix design on site. It is also useful in minimizing the cost and optimizing the mean compressive strength of concrete mixes.

Keywords

Concrete Mix Design, Mathematical Equations, Computer Program, Regression, Optimization

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