Title of Proposal: A Study on the Effect of Climate Change on Magnitude and Frequency of Rainfall Extreme events in Uganda
In the recent decades, the frequency of rainfall extreme events is on the rise in many regions of the world. These extreme rainfall events cause floods which leads to damage to life, property, infrastructure, and heritage.
In recent years several parts of Uganda have been experiencing heavy torrential rains that have caused floods which have damaged roads, bridges and swept away people’s houses and property. As a result of these damages, businesses have been greatly affected since there isn’t free movement of people and goods as results of the floods.
According to an article, published in the Daily Monitor on 18th April 2018, a bridge on river Manafwa that has been in existence for over 40 years was submerged as a result of heavy rains. In the same article, it is ascertained that food crops and animals had also been destroyed by the floods. CITATION WAD18 l 2057 (WADERO, 2018)
Climate change is a big concern since it may alter the frequency and magnitude of precipitation. Precipitation has a direct influence on the occurrence of extreme events like floods. According to Rajneesh Kumar and Anil Bhardwaj (2015), rainfall is one of the major constituents of the hydrological cycle and also a major source of water on earth by principle hence most of the extreme events of precipitation are directly linked to the magnitude and frequency of occurrence of rainfall. If the rainfall is too high as compared to the infiltration capacity of the soil, this results in high rates of runoff, landslides, and floods. Therefore, it is important to have knowledge of the maximum and distribution of precipitation over a catchment area. CITATION Bha15 l 2057 (Bhardwaj, 2015)
Statistical Analysis of rainfall data and related studies is very significant in hydrology and water resources assessment. This is important for planning and maintenance of water resources related infrastructure CITATION Nor16 l 2057 (Norhan Abd Rahman, 2016). It is important to also note that for proper planning for extreme weather-related emergencies, the design of hydraulic and other engineering structures, and proper management of reservoirs all rely on the knowledge of the amount and frequency of the extreme environmental events.
According to G.I. Okonkwo et. al. (2010) problems related to hydrologic risk analysis and design require a proper assessment of extreme precipitation events. This is why the study of rainfall extremes by the help of intensity-duration-frequency (IDF) relationship is a major focus of theoretical and applied hydrology.
It has been acknowledged by most of the world leaders and scientists that climate change is a reality and happening as a result of mainly human factors. This can be proved by the 2016 Paris Convention on Climate Change that saw agreement on how to compare climate change being signed by the world leaders.
Over the years the effects of climate change on the environment have caused significant changes to the environment which as a result has led to significant changes in frequency and quantity of precipitation. Due to these changes, it has become challenging for engineers to estimate the occurrence of climatic extreme events during the design of hydraulic structures. This has led to the design of hydraulic structures with inadequate capacity hence having frequent failures of these structures before their design life.
Therefore, this research seeks to carry out a study on the effects of climate change on the quantity and timing of precipitation.
The main aim of the study is to evaluate the effect of climate change on extreme precipitation events and how they affect the design of hydraulic structures.
The specific objectives of this study are;
To carry out a trend analysis of rainfall data for at least 20 years
Develop a model for storm rainfall frequency analysis and do a comparison between different methods used to select the most suitable one
Develop rainfall intensity-duration (IDF) relationship
Estimate limiting values and carry out analysis of uncertainty
Rainfall data of at least 20 years of the study area is going to be obtained from at least five stations of the study area. The data will then be subjected to analysis by the help of hydrological statistical technics.
A trend analysis will be carried out in order to identify the most severe events. Preparation of annual maximum data series will be done. This will help in the formulation of Intensity Rainfall Duration curves. Finally, analysis of uncertainty will also be performed.
Justification of the Project:
Currently, most of the hydraulic structures are designed with an assumption that hydrological events are stationary in nature. However, due to climate change as a result of increased global warming. Recent records of hydrological data in some areas have some shown some degree of non-stationarity in hydrological events.
This can also be attributed to others environmental factors like changes in land use for example; increased urbanization, agriculture, and deforestation. Hence there is an urgent need to revisit some of the concepts used in hydraulic structures design, like assessing the risk of non-stationarity of extreme events.
The significance of the Project:
This study is going to be of great benefit to the field of design of hydraulic structures by bringing to the attention of engineers the concept of relating stationarity and non-stationarity of extreme events in the design of hydraulic structures.
BIBLIOGRAPHY Bhardwaj, R. K. (2015). Probability analysis of return period of daily maximum rainfall in annual data set of Ludhiana, Punjab. Punjab Agricultural University, Ludhiana-141 001, India., Department of Soil and Water Engineering. Ludhiana: Indian J. Agric. Research.
Norhan Abd Rahman, F. A. (2016). FREQUENCY ANALYSIS OF ANNUAL MAXIMUM DAILY RAINFALL IN WADI ALAQIQ, SAUDI ARABIA. Taibah University, Department of Civil Engineering. Johor, Malaysia: Malaysian Journal of Civil Engineering.
WADERO, Y. K. (2018, April 18). Hundreds stranded in Butaleja as floods cut off the road. Dialy Monitor.