Assessment for the renewal and management of stormwater drainage facilities in residential areas of Enugu city, Nigeria (original) (raw)
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Performance-Assessment of Existing Drainage Facilities for The Purpose of Stormwater Management
LAUTECH Journal of Civil and Environmental Studies, 2020
The study assesses the performance of the existing drainage facilities in some selected areas in Ilorin Metropolis of Kwara State, Nigeria. The rapid increase in urbanization, increase in population without corresponding infrastructures in the city of Ilorin have led to the increased incidence of flood as the available drainage channel cannot convey the volume of water. The study focuses on the household demograph, flooding, drainage maintenance and solid waste management strategies employed in the study areas. The methodology involves the use of questionnaires and interview method to gather information from the respondents of the study areas. The study was carried out with 200 copies of well-designed questionnaire through systematic random sampling technique in the administration. The research questions were answered using tables of frequencies and percentages, bar chat, pie chart and regression analysis for flood modelling and prediction of flood occurrence. The analysis revealed ...
ARC ABU JOURNAL, 2018
Informal urbanism is the major driver of city development in African cities. In such a scenario where most settlements do not have defined or formal layouts, urban drainage development can become quite a challenge. This paper examines the phenomenon of urban stormwater drainage development in Palladan, an unplanned neighbourhood in Zaria, in order to understand how informal urbanism shapes the development of urban drainage. The study focused more on the social and environmental aspects. A case study, field survey approach was adopted with150 households selected through systematic random sampling. The questionnaires were administered to them to get socioeconomic data and their opinions on the environmental and social aspects of drainage development in their neighbourhood. Simple descriptive statistics were used to analyze the data. The findings reveal that drainage provision at neighbourhood level is largely subject to individual, household or communal efforts. There is also no defined drainage hierarchy and connectivity in the area, while solid waste is often dumped in existing drainage. These result in cases of some residents experiencing perennial flooding. The paper also found that residents in the area had at one time or the other been involved in drainage related social conflict. On the positive side, most of the respondents were owner occupiers who are ready to contribute and make sacrifices towards drainage development. The paper concludes by suggesting strategies for sustainable stormwater drainage development in unplanned neighbourhoods which includes a coordinated collaboration of actors in drainage development.
This study attempts to determine the appropriate locations and sizes of drainage structures that can handle surface runoff in all watersheds of the study area (i. e. Jimeta Metropolis) without endangering lives and properties. Surface runoff is the excess water that flows over the land after the soil is infiltrated as a result of heavy rainfall while a watershed is defined as the area of land that drains to a particular point. Among various methods of determining the quantity of surface runoff, rational method is considered for this study. This is because previous attempts have shown that the concept of rational method is simple and good for relatively small watersheds as those covered in this study. The data used are the rectangular coordinates of points and the rainfall data of the study area for the year 2011. The method includes the determination of the locations and volumes of the drainage structures, Time of Concentration (ToC), Rainfall Intensity (I), Runoff Coefficient (C) and hence the estimated quantities of the surface runoff. Analyzing the results obtained, it was observed that the locations of the drainage structures are appropriate. However, the drainage structures of some watersheds are smaller than the required sizes thereby posing the risk of endangering lives and properties. That is, the existing volumes of the structures are smaller than the estimated volumes of the surface runoff. Therefore, it is recommended that the estimated quantity of surface runoff in a particular watershed should serve as a bench mark for the determination of appropriate location and size of drainage structure to be constructed for such watershed.
FUOYE Journal of Engineering and Technology
Among areas prone to flood disaster yearly in Ilorin is Isale koko. The study involved the reconnaissance survey to ascertain the current capacity of the existing drainage in the flood disaster prone area of Isale Koko, Ilorin, Kwara State, Nigeria. The dimension of the drainage network of the area was taken at eight (8) various points and the average area of the drainage was obtained to be 0.44m². The already existing drainage in the area was divided into 3 sections for easy computations of flow value, length, depth and width. The rainfall intensity for the study area was found to be 98.49mm/hr. The rational method and Manning’s equation were used for the surface runoff and the proposed drainage respectively. The peak flow of the area and maximum flow velocity in the drains were determined to be 48.46mᶟ/s and 2.21mᶟ/s respectively. The best hydraulic section method was employed to obtain new drainage dimensions for both rectangular and trapezoidal channels. The new designed rectan...
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Yenagoa, capital city of Bayelsa State, lies in floodplain and surrounded by freshwater swamp and tributaries of the Nun River, Ekole and Epie Creeks, lakes and other natural drainage paths. But the City is annually inundated most times of the year. The goal of this research is to assess and recommend an effective storm water management system in the city. Objectives of the study include: assessing the challenges posed by storm water, identify climatic and hydrological settings of the study area, (c) develop an effective management strategy to mitigate the problem. Multi-stage sampling procedure was adopted and purposively select 6 communities from 22 identified communities, 95 questionnaires were administered. Spearman Rank Correlation was used to test the relationship between adequacy of drains and annual flooding incidence. The study found that; extensive uncontrolled development on wetlands fuelled rapid urbanisation, lack of drainage in many communities and the major roads in t...
Urban Drainage: The Challenges and Failure Assessment Using AHP, Addis Ababa, Ethiopia
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Urban drainage infrastructures are facing critical challenges due to a lack of integrated asset management, periodic maintenance, improper design, and construction methodologies. The objective of this study is to understand the urban drainage challenges and assess the failure causes and their impacts to recommend possible mitigation measures. Drainage failure causes and impacts are analyzed using the analytical hierarchy process (AHP) qualitative multicriteria decision model after conducting technical group discussions, interviews, and technical field surveys. The assessment was performed by taking representative samples from both cross- and longitudinal drainage infrastructures. The AHP analysis results showed that approximately 35.5% and 28.6% of failure causes are debris and various solid wastes for cross- and longitudinal drainage structures with correlation coefficients of 0.93 and 0.95, respectively. The result showed that design and construction defects are the second major f...
2019
Yenagoa, capital city of Bayelsa State, lies in floodplain and surrounded by freshwater swamp and tributaries of the Nun River, Ekole and Epie Creeks, lakes and other natural drainage paths. But the City is annually inundated most times of the year. The goal of this research is to assess and recommend an effective storm water management system in the city. Objectives of the study include: assessing the challenges posed by storm water, identify climatic and hydrological settings of the study area, (c) develop an effective management strategy to mitigate the problem. Multi-stage sampling procedure was adopted and purposively select 6 communities from 22 identified communities, 95 questionnaires were administered. Spearman Rank Correlation was used to test the relationship between adequacy of drains and annual flooding incidence. The study found that; extensive uncontrolled development on wetlands fuelled rapid urbanisation, lack of drainage in many communities and the major roads in t...
Design of storm water drainage for an estate at epe in Lagos state, Nigeria.
International Journal of Hydrology, 2018
The research was intended to design facilities to manage storm water for a new estate, and the scope is to determine the possible flood extent using the rational method and then provide the flows that each sewer is required to be designed to carry in order to properly drain the estate in the event of rainfall storm. The estate is located on 20 hectares of land along Lekki Express Freeway between Lagos and Epe. There's a bridge located to the north of the estate that drains the estate and the adjourning regions. The site is generally well drained, draining from South to North and East to West. The estate is a sub-catchment of a bigger catchment area that drains partly as a river that flows into the estate through its western boundary on its way to the bridge outlet to the north western section of the estate. The total catchment area contributing to flow within the estate amounts to 214335.80m 2 while the total catchment area contributing to flows within the estate and those flowing through the estate to the bridge and towards the north of the estate amount to 234955.80m 2 . Gumbel Extreme Value Distribution was used to determine the Intensity Duration Frequency (IDF) was gotten and the rainfall intensities for the shortest duration (15minutes) for various return periods of 5, 10, 50, and 100 years were gotten and flow then determined that will feed each sewer produced on the site. The flood levels on the estate fence and at the adjacent bridge were also determined for 30-year Return Period through interpolation on the IDF curve to be 4.85m and 5.340m with the bench mark being 3.39m taken from the bridge.