Flood Simulation Models for a River System in a Tropical Region: The Case of Linggi River, Malaysia

Flooding of a river system in a tropical region is predicted using mathematical simulation models in this study. The proposed models were categorized as hydrologic model, hydraulic model and sedimentation model. Two methods of hydrologic models were used to simulate the peak: streamflow in a river system of a tropical region. The first hydrologic model is the river model, which is a first order linear autoregressive model, AR(1). The second hydrologic model is called the basin model which is a deterministic model based on a linear relationship between rainfall and runoff. The basin model is also described as a distributed model in which the river basin is divided into a number of subbasins whereby the rainfall and the runoff at each subbasin is simulated separately and then combined to get the river basin response. The Linggi River system in Seremban, Malaysia was used as a case study. The Linggi River system consists of a main river which is called Linggi, and it's six tributaries called the Batang Penar, Paroi, Temiang Diversion, Temiang, Anak Rasah and Kepayang. The total catchment area of the Linggi River system up to the point of interest is 127.7 km2. Recorded hydrologic data for the Linggi River basin was used in the evaluation and testing of the proposed models. Models evaluation involved calibration, verification and sensitivity analysis. Models testing was implemented using the Theil's technique. The calculated value of Theil's coefficient was 0.028, 0.17 and 0.01 for the basin model, river model and the hydraulic model respectively. A computer program was written to especially perform the calculations of the basin model. This computer program is called BSHYMD

Evaluation of yield and groundwater quality for selected wells in Malaysia

In Malaysia, the use of groundwater can help to meet the increasing water demand. The utilization of the aquifers is currently contributing in water supplies, particularly for the northern states. In this study, quantitative and qualitative assessments were carried out for the groundwater exploitation in the states of Kelantan, Melaka, Terengganu and Perak. The relevant data was acquired from the Department of Mineral and Geoscience, Malaysia. The quantitative assessment mainly included the determination of the use to yield ratio (UTY). The formula was proposed to determine the UTY ratio for aquifers in Malaysia. The proposed formula was applied to determine the maximum UTY ratios for the aquifers located in the states of Kelantan, Melaka, and Terengganu, and were found to be 4.2, 5.2 and 0.6, respectively. This indicated that exploitation of groundwater was beyond the safe limit in the states of Kelantan and Melaka. The qualitative assessment showed that the groundwater is slightly acidic. In addition, the concentrations of iron and manganese were found to be higher than the allowable limits, but the chloride concentration was found within the allowable limit

Groundwater engineering and geotechnique

This book comprises nine chapters designed to cover the syllabus of the subject of Groundwater Hydraulics with some theory and application which is considered important for civil engineers. Post graduate students, and researchers. Many topics covered in this book are useful for undergraduate students doing the Civil Engineering programme. Information on the history of groundwater, the geological formation of aquifers and groundwater utilisation is also included in this book

Tools for Drought Identification and Assessment: A Review

Drought is a natural phenomenon in many arid, semi-arid, or wet regions. This showed that no region worldwide is excluded from the occurrence of drought. Extreme droughts were caused by global weather warming and climate change. Therefore, it is essential to review the studies conducted on drought to use the recommendations made by the researchers on drought.  The drought was classified into meteorological, agricultural, hydrological, and economic-social. In addition, researchers described the severity of the drought by using various indices which required different input data.  The indices used by various researchers were the Joint Deficit Index (JDI), Effective Drought Index (EDI), Streamflow Drought Index (SDI), Standard Precipitation Index (SPI), Standard Evapotranspiration Index (SPEI), and Palmer Index (PI). According to the researchers in hydrology and for the most accurate description of the drought, more than one indicator for drought should be used. Most reviewed studies recommended using the Standard Precipitation Index (SPI) as the best indicator to describe the drought.

Kinematic analysis of blocks in tunnel on the basis of discontinuities.

This paper demonstrates the advantages of using stereographic projections in kinematic analysis of rock blocks in excavation surface. The stereographic method is completed by planes and poles as points and lines on the horizontal surface and the block kinematic behavioral analysis is investigated in a rock free face subsequently. A block is considered to be an instable one when the intersection lines fall into the critical zone, this area is defined through the relationship between the friction angle of the stone mass and the slope of the free face respectively. It is possible to determine the movement of the blocks on the basis of the discontinuity position before any collapse or sliding happens

Oil Removal from Oilfield Produced Water, North Rumaila by Combination CoagulationFlocculation and Microfiltration Technique

The Southern Oil Company, which is operated in North Rumaila oilfield in Basrah/ Iraq, is one of the important companies which produced huge amounts of produced oilfield water. The aim of this study is to treat the produced water by hybrid methods: the process of coagulation-flocculation and microfiltration technique (ceramic membrane) to remove the oil content and improve the water quality to meet the allowable limit of reinjection into the reservoir. Poly-aluminum chloride (PAC), and Ferric Chloride (FeCl3.6H2O) coagulants were used separately and in combination with cationic polyelectrolyte (PE). After produced water was treated with different doses of coagulant, it was passed through the Microfiltration technique/ ceramic membrane (0.5µm) to reach the allowable limit for reinjection. It was found that the best value of oil content after passing through ceramic membrane is 0.2 mg/L at FeCl3.6H2O dose (10 mg/L) combined with PE dose (0.6 mg/L), which was less than the allowable limit for re-injection, (5) ppm

Numerical study on the performance of shell footing

This paper describes a study on the performance of shell footings using a non-linear finite element analysis with a finite element code, PLAXIS. The shell footing is found to have a better load carrying capacity compared with the conventional slab (flat) footing of similar cross sectional area. The FE analysis also showed a reasonably good agreement with the laboratory experimental results. The effect of increasing the embedment ratio is also studied and found to increase the load carrying capacity of the shell footings

Empirical model simulating rainwater harvesting system in Tropical area

Rainwater harvesting is the technique of capturing the rainfall to meet some water needs in both urban and rural areas. The volume of rainwater collected from rainwater harvesting system varies from place to place and depends mainly on the climatic condition. Typically, the rainwater harvesting system is composed of the catchment (roof), gutter, rainwater pipe, and storage tank. Reliability of a rainwater harvesting system mainly depends on the collected volume in rainwater storage tank and it is also used to check whether the collected volume of rainwater can meet a specific water demand (either for potable or non-potable uses). In the present study, a rainwater harvesting system is installed at the Faculty of Engineering, University Putra Malaysia. The system is tested using data from 24 different rain events. The collected data includes rain depth and rainwater volume. It is found that the rainwater volume ranges form 0.027 m³ to 4.03 m³. The actual data is used to produce an empirical model for predicting the collected rainwater volume. Calibration and validation processes are conducted to the proposed model and T-test shows that the model prediction is within 95% level of confidence. Also, the water consumption for toilet flushing is monitored using water meter. Reliability of the installed rainwater harvesting system for toilet flushing is computed. It is found that the system reliability ranges from 26.61 % to 100 % depending on daily water demand and recorded rainwater depth