An Aquifer Reflections on Deep Clay Conditions for Water Quantity Assessments

This study aims to evaluate the on-site testing of deep clay area through the well response and aquifer reflection analysis. The analysis was conducted using AQTESOLV software on pumping and recovery data to determine the well responses and aquifer characteristics of deep clay area. A simple experimental model was installed at the site using deep well of REWES (Recharge Well System) model assists with four monitoring wells around the model. The monitoring wells were located at 4m, 10m, 20m and 35m from the model. The site has been identified identified to have the unconfined aquifer with deep compacted clay. Due to flatten and low flow, pumping analysis and ground water response were used to evaluate water quantity and potential prospective of circulate water cycle for urban stormwater management. As reflection on water cycle, almost 20% from withdrawal capacity able to refill the ground system with limited space. It was found that the available storage, S and hydraulic conductivity, K  of the clayey area are 0.001 and 32 m/day respectively. Therefore, the response on water cycle indicate some potential space to restore and withdrawal at peak time and thus, the  water can be used in safely conditions.&nbsp

Estimation of Missing Rainfall Data Using GEP: Case Study of Raja River, Alor Setar, Kedah

Water resources and urban flood management require hydrologic and hydraulic modeling. However, incomplete precipitation data is often the issue during hydrological modeling exercise. In this study, gene expression programming (GEP) was utilised to correlate monthly precipitation data from a principal station with its neighbouring station located in Alor Setar, Kedah, Malaysia. GEP is an extension to genetic programming (GP), and can provide simple and efficient solution. The study illustrates the applications of GEP to determine the most suitable rainfall station to replace the principal rainfall station (station 6103047).This is to ensure that a reliable rainfall station can be made if the principal station malfunctioned. These were done by comparing principal station data with each individual neighbouring station. Result of the analysis reveals that the station 38 is the most compatible to the principal station where the value of R2 is 0.886

Sediment deposition characteristics of urban concrete drains in Kuching City, Sarawak, Malaysia

Sediment deposition in drains has been found to be one of the major causes of flooding in urban areas. In order to design an effective removal mechanism, an understanding of the characteristics of the sediment deposition is needed. This paper highlights the results of sediment size characteristics analysis done on sediment samples collected from concrete drains in Kuching city, Sarawak, Malaysia. A total of 30 sediment samples from 10 urban locations (4 residential areas, 5 commercial areas and 1 industrial area) were collected and subjected to sieve analysis. Results from sieve analysis had shown that the major component of the sediment is sand with an average percentage of 68.8%, followed by gravel with average percentage of 30.4% and silt and clay as the minor component with an average percentage of 0.8%. Of the 30 samples, 7 samples show bimodal characteristics while 23 samples show unimodal characteristics. 14 out of the 23 unimodal samples had shown a non uniform distribution with the tendency to skew to the coarser grain size. Due to this, the conventional use of median grain size d50 as the effective size for the sediment samples might not be a good representation for the sediment distribution. Further statistical analysis in this paper had suggested that the mode grain size is a much better representative grain size due to its stability when compared to median and mean size. Thus, a much better representative size for the sediment samples from Kuching urban areas would be the mode size (in this case is d45). An analysis on drain characteristics had shown that trapezoidal shape drain tends to have higher blockage percentage due to sediment deposition when compared to rectangular shape drain

Duration of Hydraulic Flushing and its Effect on Sediment Bed Movement

Hydraulic flushing is the most widely used method for sediment removal in sewer. However, open storm sewer tend to have longer flushing duration as compared to closed conduit sewer. This is due to storm water could enter more directly and rapidly into open storm sewer especially during rain events. The current study aims to determine the effect of flushing duration on the efficiency of sediment removal which is lacking in the literature. Flushing experiment was conducted in a rectangular flume for varying flushing durations namely approximately 3 seconds, 30 minutes and 60 minutes. Changes of the sediment bed profile were observed after each flush. Findings from the experiment has shown that short duration flushing is more efficient in terms of more sediment volume being removed as compared to long flushing duration. In terms of mean sediment bed front advancement, long flushing duration will moved the sediment bed front further than short duration flushing. The knowledge from the current study can be used to design a more efficient flushing devices for the management and active control of sediment in sewer system

Duration of Hydraulic Flushing and its Effect on Sediment Bed Movement

Hydraulic flushing is the most widely used method for sediment removal in sewer. However, open storm sewer tend to have longer flushing duration as compared to closed conduit sewer. This is due to storm water could enter more directly and rapidly into open storm sewer especially during rain events. The current study aims to determine the effect of flushing duration on the efficiency of sediment removal which is lacking in the literature. Flushing experiment was conducted in a rectangular flume for varying flushing durations namely approximately 3 seconds, 30 minutes and 60 minutes. Changes of the sediment bed profile were observed after each flush. Findings from the experiment has shown that short duration flushing is more efficient in terms of more sediment volume being removed as compared to long flushing duration. In terms of mean sediment bed front advancement, long flushing duration will moved the sediment bed front further than short duration flushing. The knowledge from the current study can be used to design a more efficient flushing devices for the management and active control of sediment in sewer system