Plotting position for low flow frequency analysis at jempol river streamflow station

Low flow frequency analysis is an important technique for calculating the probability of river flow availability during crucial low flow seasons, such as drought. It is also useful to predict the low flow information of a river in volume and frequency for future planning and construction of water resource projects since the low flow has a significant impact on water quality, water supply, and river sustainability conditions. Therefore, this study was performed to determine the low flow frequency analysis of the Jempol River streamflow station using Weibull and Gringorten plotting position formulas. The average recurrence interval (ARI) of 2-, 5-, 10-, 25-, 50-, and 100-year were determined based on 18 years of historical streamflow data. The study illustrates the annual minimum flow magnitude of 1-, 4-, 7-, and 30-day durations for the study area. It shows that the Gringorten formula tends to give higher estimation values up to 18% compared to the Weibull formula when the flow duration increase. Therefore, the outcome of this study could be used in the future for any project related to the low flow information of Jempol River

Field investigation of seasonal variations impact on flow depths and velocities in the swash zone

Most studies of the hydrodynamics and sediment transport in the swash zone in recent years have stressed the importance of swash processes in terms of science advancement and practical applications in this field of study. Clearly, the hydrodynamics of the swash zone are complex and not fully understood. The hydrodynamics of the swash zone characteristics likes swash water depth and velocity will affected the sediment transport mechanisms that mostly control beach face morphology especially under dry and wet periods in east coast region of Peninsular Malaysia. Field monitoring works at Desaru beach for data of rainfall distribution, morphological changes and swash characteristics likes flow depths and velocities have been conducted and analysed for both different periods (dry and wet). From observation, it is believed that rainfall distribution during the seasonal variation of dry and wet seasons in Malaysia affects the swash characteristics mainly by the infiltration processes in beach areas and significantly controlled the morphological changes in the swash zone

Investigation of Sewage Flows in Universiti Malaysia PAHANG’s Sewerage System

Sewerage systems have long been one of the most critical infrastructure to any development project. The study presented here is part of a research that aim to evaluate the flow characteristics in sewerage systems. Sewage flow data was collected from a sewerage catchment within Universiti Malaysia PAHANG using an area-velocity flowmeter. The data obtained were extracted using a software associated to the flowmeter and analyzed for both dry and wet periods. The results show that the peak or maximum flow for the wet period with a rainfall intensity of 2.5 mm was twice as high for the dry period. The design criterion value back-calculated for the wet period was also twice the value for the design criterion value back-calculated for the dry period. This demonstrates that rainfall has an important effect on flows in sewerage system in that it increases the flow significantly. The k value back-calculated for both dry and wet periods were lower than the criterion recommended in Malaysian Standard MS1228:1991, suggesting that the current peak flow factor equation applied by the industry is over-adequate for sewerage catchments servicing the same population equivalent as this study

Study on Characteristics of Sediment and Sedimentation Rate at Sungai Lembing, Kuantan, Pahang

AbstractRiver is important in human life. River is very useful and has various functions in human life such as for domestics, economics, connection for one place to others place and many more. The main function of the river is to flow the water to the water storage or sea. River also brings the sediment from upstream or from erosion process. Sediments may affect the characteristics and the rate of the river. The study of sedimentation rate is quite important for development our country. It also can avoid the problem which related to our human society such as flood and water quality. As example, the depth of river become shallow if the sedimentation occurred. It also will make the quantity of aquatic life will reduced. This study was carried out to determine the sedimentation rate for five locations in the study area at Sungai Lembing, Kuantan, using Duboys and Schoklitsch equation. The highest sedimentation rate using Duboys is 2.06 lb-sec/ft was obtained at Station 3 and the lowest sedimentation rate is 0.073 lb-sec/ft also at Station 3 but in different day. Meanwhile, by using Schoklitsch equation, the highest rate is 1.12 lb-sec/ft at Station 1 and the lowest rate at Station 5 with 0.263 lb-sec/ft. The results for Duboys indicated that the rate is related to the mean size of sediment and the cross section of the river. By using Schoklitsch, the results depend on the flow rate of the river. If the flow rate higher, the sediment rate will also increase. The sediment sample sieving test results was classified using U. S. Army Corps of Engineer (USACE). The major size at Sungai Lembing for every station is in range between 2 mm-0.5mm (Medium sand) and the minor size of sediment for the five ungauged station is 0.25 mm- 0.0625mm (very fine sand)

Effect of Inflow and Infiltration in Sewerage System of Residential Area, Kuantan, Pahang

Inflow and infiltration is a phenomenon in sewerage systems that can have negative effects on the environment and human health if not treated properly. Collaboration has been made between Universiti Malaysia Pahang (UMP) and Indah Water Konsortium Sdn. Bhd. (IWK) where the purpose is to evaluate the amount of inflow and infiltration happening in sewerage systems of residential areas in Kuantan. For this part of the study, one sewer pipeline (MH92a–MH92b) was selected at the residential area of Bandar Putra, having a population equivalent of 1694. The method used in this research was the Flowrate method to tabulate data. ISCO 2150 and 4250 Area Velocity Flowmeters were used to measure flow rate data in the sewer pipeline, whereas ISCO 674 Rain Gauge was used to collect rainfall intensity data. Calibration of all the equipment was done at the Hydrology and Hydraulic Laboratory in UMP. The data was collected for 41 days with each measurement separated by an interval of five minutes. The result shows that the average percentage Infiltration Rate of Qpeak and Qave in this residential catchment were 10.3% and 26.5% which is higher than the value mentioned in Hammer and Hammer (2012). Inflow and infiltration is a real concern, so more study is required to determine whether revision of the infiltration rate recommended in the Malaysian Standard is needed

Investigation of depth-area-duration (DAD) curves for Kuantan River Basin (KRB)

Depth-area-duration (DAD) analysis of rainfall is performed to evaluate the maximum amount of rainfall over areas of various sizes within different durations. It is frequently used to characterize precipitation extremes for the specification of so-called rainfall, with DAD curves resembling the correlation between rainfall depth and area. Kuantan River Basin (KRB) is one of the major rivers in Pahang that typically experiences heavy precipitation during the northeast monsoon season from November through March. In this study, DAD curves for KRB were developed for the duration of 1-day to 7-day. Daily rainfall data between 2008 to 2019 from eight stations in KRB were used to develop the DAD curves. DAD curve development initially requires an isohyet map's illustration that can be constructed through the interpolation of Inverse Distance Weighting (IDW) method. The isohyet maps were developed in the ArcGIS software to purposely obtain the average maximum rainfall depths for each rainfall duration. The maximum rainfall amount of 1-day up to 7-day durations increased from 394.45 mm to 857.61 mm. The results indicated that the maximum amount of rainfall will increase along with the duration from 1-day to 7-day. The gap between the final DAD curve of 6-day and 7-day was less compared to other duration curves; however, the gap for both curves increased from the 800 km2 to 1000 km2 areas where the gap differences between the curves accelerated from 12 mm to 34 mm. Final DAD curves of KRB were produced from the combination of initial DAD curves with durations ranging from 1 to 7 days. The DAD curves produced in this study can provide further information on the maximum rainfall depth under different storm durations for hydrological planning purposes, particularly in KRB

Preliminary inflow and infiltration study of sewerage systems from two residential areas in Kuantan, Pahang / Hiew Thong Yap

Sewerage system is the sole infrastructure which conveys sewage to sewerage treatment plants. The usage of a sewerage system should be optimized at the design stage to enhance environmental protection and human health. Wastewaters flows are produced from domestic sewage whereas inflow and infiltration come from surface runoff and groundwater. The purpose of this study is to identify inflow and infiltration in sewerage systems around Kuantan. This study was conducted in residential catchments at Taman Lepar Hilir Saujana and Bandar Putra with population equivalent of 1253 and 1694, respectively. ISCO 674 Rain Gauge was used to measure rainfall intensity. ISCO 2150 and 4250 Area Velocity Flowmeters were collected wastewater flowrate data which measured at 5-minute intervals and analyzed separately for wet and dry period. Infiltration rate was obtained by comparing the upstream flow and downstream flow from the two selected manholes. Based on the result, the average infiltration rate of Qpeak and Qave was 13.7% and 21.2% higher than the 5% and 10% stated in Hammer and Hammer. Inflow and infiltration is a concern and more comprehensive studies are needed to initiate the review of a revised infiltration rate that is more relevant to the future climate

Simulation of saltwater intrusion in alluvial aquifer at Kg. Tekek, Tioman Island

Tioman Island, which is situated in the southeast of Pahang State, is one of the small islands in Malaysia that have been promoted as a tourist destination. Previous studies have shown that, the supply from surface water is limited and fluctuated seasonally. Therefore, it is necessary and urgently a need to identify new water resources to meet the growing demand due to both local population and tourism industry to prevent serious water crisis by the year 2025. The alternative source, to supplement surface water will be the groundwater. The development and management of fresh groundwater resources in coastal aquifers are seriously constrained by the presence of saltwater intrusion. There exists a need to study systematically the causes and remedial measures for saltwater intrusion due to withdrawal of groundwater. This study presents the simulation of two numerical models for saltwater intrusion in Kg. Tekek, Tioman Island through Saturated-Unsaturated TRAnsport (SUTRA) model to simulate the groundwater flow based on the available data. The simulation model used in this work has assumed homogeneous aquifer properties. The study also concentrates on the saltwater intrusion due to pumping activities at different mode of pumping rate under unsteady state condition. The results of this study highlight the effects of pumping on saltwater intrusion where less pumping and high recharge rate in the aquifer can reduce saltwater intrusion effectively

Influence of seasonal hydrological variation on swash zone morphological changes

Studies on hydrodynamics of sediment transport in recent years stressed on knowledge advancement and practical applications of swash processes. The hydrodynamic processes significantly affect sediment transport mechanisms that control beach face morphology. In Peninsular Malaysia, seasonal variation of dry and wet periods in the months of May to September and November to March respectively, noticeably influenced the evolution of beach profile. This study investigates the influence of seasonal hydrological variation to beach groundwater table and how it affects swash zone morphological changes. Field monitoring was carried out at a section of Desaru beach, Johor for 30-months consisting of data on a beach cross-shore profile, rainfall distribution, groundwater table, tidal variation and swash flow velocity and depth. These were monitored and investigated to check for patterns of interrelationships among the parameters. Results indicated that the seasonal variation of Desaru beach morphology was primarily controlled by the cross-shore exchange of sediment in the swash zone. The beach profiles showed erosive condition due to seaward sediment movement during the wet season, while during the dry season, the beach profile showed accretion condition due to the increase of landward sediment movement. The total sand volume at Desaru beach was found to be highly correlated (R2 = 0.86) with the shoreline position. For detailed beach profile analyses, the Empirical Orthogonal Function (EOF) technique was applied and showed changes in profile configuration as a function of space and time. The analysis confirmed that the swash zone of Desaru beach is the most dynamic region on sandy beach with cyclic processes of erosion and accretion. Most of the variation in the beach profiles can be explained by the first five eigenfunctions (EOF1-EOF5) that has the highest eigenvalues. It was revealed that 99.99% of the data variance was captured by these eigenfunctions. This confirmed that the method provides a means of presenting space and time variability of beach profiles. The study also illustrated that the groundwater table elevation was influenced by rainfall patterns where higher groundwater table during the wet season and lower groundwater table during the dry season was observed. The fluctuating groundwater table is an important mechanism to explain the role of infiltration and exfiltration processes in the morphology of swash zones. The relationship between the average shoreline position with groundwater level monitored at wells BH2 and BH3 indicated moderate correlation with values of R2 equals to 0.75 and 0.67, respectively. The velocity reduction of uprush to backwash flow during the dry period was higher (73.08%) compared to during wet period (46.00%). Similar pattern was found in the swash flow depth analysis where the reduction percentage showed higher reduction during the dry period (52.17%) compared to during the wet period (24.64%). This study quantified seasonal hydrological variation influence on the swash zone morphological changes and provided a better understanding of beach profile evolution, leading to improved beach management practices in Malaysia

Study on Characteristics of Sediment and Sedimentation Rate at Sungai Lembing, Kuantan, Pahang

River is important in human life. River is very useful and has various functions in human life such as for domestics, economics, connection for one place to others place and many more. The main function of the river is to flow the water to the water storage or sea. River also brings the sediment from upstream or from erosion process. Sediments may affect the characteristics and the rate of the river. The study of sedimentation rate is quite important for development our country. It also can avoid the problem which related to our human society such as flood and water quality. As example, the depth of river become shallow if the sedimentation occurred. It also will make the quantity of aquatic life will reduced. This study was carried out to determine the sedimentation rate for five locations in the study area at Sungai Lembing, Kuantan, using Duboys and Schoklitsch equation. The highest sedimentation rate using Duboys is 2.06 lb-sec/ft was obtained at Station 3 and the lowest sedimentation rate is 0.073 lb-sec/ft also at Station 3 but in different day. Meanwhile, by using Schoklitsch equation, the highest rate is 1.12 lb-sec/ft at Station 1 and the lowest rate at Station 5 with 0.263 lb-sec/ft. The results for Duboys indicated that the rate is related to the mean size of sediment and the cross section of the river. By using Schoklitsch, the results depend on the flow rate of the river. If the flow rate higher, the sediment rate will also increase. The sediment sample sieving test results was classified using U. S. Army Corps of Engineer (USACE). The major size at Sungai Lembing for every station is in range between 2 mm-0.5 mm (Medium sand) and the minor size of sediment for the five ungauged station is 0.25 mm- 0.0625 mm (very fine sand)