Noor Aliza Ahmad

Variations of Roughness Coefficients with Flow Depth of Grassed Swale

Grassed swales are the best management practice (BMP), which has been widely used to reduce the peak flow, reduce water pollution through vegetated filtration, and improve the groundwater recharge. Universiti Tun Hussein Onn Malaysia (UTHM) is using the approach of grassed swales recommended by the Department of Irrigation and Drainage Malaysia (DID) for reducing the risk of flooding and controlling the water pollution. This paper investigates the variations of roughness coefficients with the flow depth of grassed swales in the campus of UTHM. Fieldwork was carried out on the grassed swale to collect the hydraulic data, which including the levelling work, measuring the flow depth and flow velocity of the swale. The flow depth of swale was taken at three points divided along the width of swale and the flow velocity is captured three times at each of the point. The variations of roughness coefficients of grassed swales are presented in Mannings equation, and the results reveal that the n value increases with the increasing of flow depth. Mannings coefficient value found in this study is in the range of 0.110 to 0.756, which are higher than the value proposed by the Urban Stormwater Management Manual for Malaysia (MSMA). The relationships of flow depth and velocity at each section of the swale are portrayed in graphs, which show that the velocity increases with the decreasing of flow depth. The outcomes of this study can be concluded that the variation of Mannings coefficient value is influenced by the swale profile, flow depth, flow velocity, and as well as the vegetation used in the grassed swale concerned.

Determination of Flow Resistance Coefficient for Vegetation in Open Channel: Laboratory study

This study focused on determination of flow resistances coefficient for grass in an open channel. Laboratory works were conducted to examine the effects of varying of roughness elements on the flume to determine flow resistance coefficient and also to determine the optimum flow resistance with five different flow rate, Q. Laboratory study with two type of vegetation which are Cow Grass and Pearl Grass were implementing to the bed of a flume. The roughness coefficient, n value is determine using Mannings equation while Soil Conservation Services (SCS) method was used to determine the surface resistance. From the experiment, the flow resistance coefficient for Cow Grass in range 0.0008 - 0.0039 while Pearl Grass value for the flow resistance coefficient are in between 0.0013 - 0.0054. As a conclusion the vegetation roughness value in open channel are depends on density, distribution type of vegetation used and physical characteristic of the vegetation itself

Flood Water Level Mapping and Prediction Due to Dam Failures

Sembrong dam has undergone overflow failure. Flooding has been reported to hit the town, covering an area of up to Parit Raja, located in the district of Batu Pahat. This study aims to identify the areas that will be affected by flood in the event of a dam failure in Sembrong Dam, Kluang, Johor at a maximum level. To grasp the extent, the flood inundation maps have been generated by using the InfoWorks ICM and GIS software. By using these maps, information such as the depth and extent of floods can be identified the main ares flooded. The flood map was created starting with the collection of relevant data such as measuring the depth of the river and a maximum flow rate for Sembrong Dam. The data were obtained from the Drainage and Irrigation Department Malaysia and the Department of Survey and Mapping and HLA Associates Sdn. Bhd. Then, the data were analyzed according to the established Info Works ICM method. The results found that the flooded area were listed at Sri Lalang, Parit Sagil, Parit Sonto, Sri Paya, Parit Raja, Parit Sempadan, Talang Bunut, Asam Bubok, Tanjung Sembrong, Sungai Rambut and Parit Haji Talib. Flood depth obtained for the related area started from 0.5 m up to 1.2 m. As a conclusion, the flood emanating from this study include the area around the town of Ayer Hitam up to Parit Raja approximately of more than 20 km distance. This may give bad implication to residents around these areas. In future studies, other rivers such as Sungai Batu Pahat should be considered for this study to predict and reduce the yearly flood victims for this area.

THE STUDY ON EFFECTIVENESS AND FLOW CHARACTERISTIC OF GRASSED SWALE DRAINAGE SYSTEM IN UTHM

The drainage system is an infrastructure that requires systematic planning of construction which can function properly to reduce the risk of flooding. Flooding occurs due to the rapid development resulting in lack of permeable surfaces. This will lead to increase the surface runoff, where the flow velocity and flow discharge also will be increased. Therefore, grassed swale is one of the sustainable drainage systems that can be applied to solve this problem. This study aims to identify the effectiveness of the grassed swale drainage system at Universiti Tun Hussein Onn Malaysia (UTHM), to determine the hydraulic characteristics and the effectiveness of vegetation used in the swale drainage system. Through this approach, the solution of past studies, related journals, and Manual Saliran Mesra Alam (MSMA) [1] are used as a reference for this study. Data collection was conducted on grassed swale with total length 60 meters. To obtain an accurate data, measurements of flow velocity have been taken three times, and for three days after raining. Data was observed by 81 times and analyzed using the Manning’s equation. Manning’s equation was adopted to determine the value of hydraulic coefficients for the grass swale channel. The results obtained, demonstrates that the value of Manning’s n for all sections is stated in a range of 0.015 to 0.030. The results also showed a difference in the size of the design, the flow velocity, the water depth, and the flow discharge of the grassed swale drainage system.

Groundwater Eco-Distribution System for the Combination of SAT and Therapy-Electrolysis Methods

Abstract. Groundwater quality is generally affected by the soil type and being polluted naturally due to the soil properties itself. This paper aims to examine the effectiveness of reducing the contamination of groundwater by a simple treatment using duo soil aquifer treatment (SAT) and therapy-electrolysis processes. The SAT was applied using physical recharge well system (REWES) in deep clay medium. The filtration in the well was also properly designed to purify the abstraction and treat discharges. Other contaminations such as fluoride, nitrate, chloride and turbidity in the groundwater were treated by therapy-electrolysis techniques. This treatment method reduces more than 64% of contaminations contain without affecting its mineralogy. Therefore, these duo treatments have the best combination of methods to reduce the unneeded contaminations without affecting the groundwater purity. A groundwater eco-distribution system is useful to be implemented in terms of economic process and is ecological friendly for water distribution facilities.