Hidayah Basri

Evaluation of green roof performances for urban stormwater quantity and quality controls

ABSTRACT Rapid urbanization in the recent decades has quickly fuelled up the process of global warming. Many mitigation measures have been formulated and implemented in order to tackle the effect of global warming. Green roofs (roof with vegetated cover) have been proposed and implemented by various countries as one of the new environmentally friendly innovation. This paper evaluates the qualitative and quantitative performances of an extensive green roof system under tropical climate. Simulations showed that the peak discharge of stormwater run-off was reduced up to 26% in relation to concrete tile roof. Its reduction ability was decreased for storms with intense rainfall. Increment of pH was observed for the green roof run-off, and the run-off quality ranged between class I and II under Malaysia National Water Quality Index (WQI). High concentrations of phosphate were observed in the run-off samples, which showed that substrates (fertilized planting soil) might be the potential contributor. Findings indicated that there was a reduction up to around 5% for indoor temperature of the building after installation of the extensive green roof system.

Homogeneity and trends in long-term rainfall data, Kelantan River Basin, Malaysia

ABSTRACT The Kelantan River Basin, situated in the northeastern Malaysian Peninsula, suffers serious flood/inundation damage, related to the northeast monsoon season (November–January), every few years. In this river basin, rainfall observation systems have been progressively developed since 1948, and long-term time-series data at distributed rainfall stations have been accumulated. This study firstly investigated the homogeneity of the accumulated time-series data for the purpose of constructing a reliable database for various hydrologic analyses. The homogeneity of rainfall time-series data was established using four absolute homogeneity tests: the Pettitt test, standard normal homogeneity test, Buishand range test, and von Neumann ratio test. It was found that among 50 rainfall stations within the river basin, 9 were flagged by the tests. Of these, inhomogeneous time-series data from four stations were omitted from further analysis. Secondly, using the homogenous time-series rainfall data, a trend analysis of annual rainfall variability was conducted by means of the Mann–Kendall (MK) test. To investigate long- and short-term characteristics of rainfall variability, three sampling methods of the MK test were applied: 30-year, sequentially increased, and 10-year moving segmented sampling. The MK test using the 30-year sampling showed a decreasing trend between 1957 and 1987, and an increasing trend between 1981 and 2011. The MK test using the sequentially increased sampling detected neither significant increasing nor decreasing trends through the same 70-year period. The MK test using 10-year moving segmented sampling clearly showed significant rainfall variability, which corresponded to the El Niño and La Niña events of 1972, 1982, 1988, the mid-1990s, and 2000–2004. Extending the plot, by comparing the turning points with the occurrence of El Niño and La Niña events, the results showed that the influence of the El Niño southern oscillation (ENSO) is the most likely to significantly influence rainfall trends in the Kelantan River Basin.

Evaluation of green roof as green technology for urban stormwater quantity and quality controls

Promoting green design, construction, reconstruction and operation of buildings has never been more critical than now due to the ever increasing greenhouse gas emissions and rapid urbanizations that are fuelling climate change more quickly. Driven by environmental needs, Green Building Index (GBI) was founded in Malaysia to drive initiative to lead the property industry towards becoming more environment-friendly. Green roof system is one of the assessment criteria of this rating system which is under category of sustainable site planning and management. An extensive green roof was constructed in Humid Tropics Center (HTC) Kuala Lumpur as one of the components for Stormwater Management Ecohydrology (SME) in order to obtain scientific data of the system. This paper evaluates the performance of extensive green roof at Humid Tropics Center with respect to urban heat island mitigation and stormwater quantity and quality controls. Findings indicate that there was a reduction of around 1.5°C for indoor temperature of the building after installation of green roof. Simulations showed that the peak discharge was reduced up to 24% relative to impervious brown roof. The results show an increment of pH and high concentration of phosphate for the runoff generated from the green roof and the runoff water quality ranged between class I and II under INWQS.

Application of Moving Bed Biofilm Reactor (MBBR) and Integrated Fixed Activated Sludge (IFAS) for Biological River Water Purification System: A Short Review

This review paper present the MBBR and IFAS technology for urban river water purification including both conventional methods and new emerging technologies. The aim of this paper is to present the MBBR and IFAS technology as an alternative and successful method for treating different kinds of effluents under different condition. There are still current treatment technologies being researched and the outcomes maybe available in a while. The review also includes many relevant researches carried out at the laboratory and pilot scales. This review covers the important processes on MBBR and IFAS basic treatment process, affecting of carrier type and influent types. However, the research concluded so far are compiled herein and reported for the first time to acquire a better perspective and insight on the subject with a view of meeting the news approach. The research concluded so far are compiled herein and reported for the first time to acquire a better perspective and insight on the subject with a view of meeting the news approach. To this end, the most feasible technology could be the combination of advanced biological process (bioreactor systems) including MBBR and IFAS system.

Impact resistance performance of green construction material using light weight oil palm shells reinforced bamboo concrete slab

This paper investigate the performance of lightweight oil palm shells (OPS) concrete with varied bamboo reinforcement content for the concrete slab of 300mm x 300mm size reinforced with different thickness subjected to low impact projectile test. A self-fabricated drop-weight impact test rig with a steel ball weight of 1.2 kg drop at 1 m height has been used in this research work. The main variables for the study is to find the relationship of the impact resistance against the amount of bamboo reinforcement and slab thickness. A linear relationship has been established between first and ultimate crack resistance against bamboo diameters and slab thickness by the experiment. The linear relationship has also been established between the service (first) crack and ultimate crack resistance against the bamboo reinforcement diameter for a constant spacing for various slab thickness using 0.45 OPS and 0.6 OPS bamboo reinforced concrete. The increment in bamboo diameter has more effect on the first crack resistance than the ultimate crack resistance. The linear relationship has also been established between the service (first) crack and ultimate crack resistance against the various slab thickness. Increment in slab thickness of the slab has more effect on the crack resistance as compare to the increment in the diameter of the bamboo reinforcement.

Probable maximum precipitation (PMP) over mountainous region of cameron highlands-batang padang catchment of Malaysia

The Cameron Highland Batang Padang (CHBP) catchment situated on the main mountain range of Peninsular Malaysia is of large economical importance where currently a series of three dams (Sultan Abu Bakar, Jor and Mahang) exist in the development of water resources and hydropower. The prediction of the design storm rainfall values for different return periods including PMP values can be useful to review the adequacy of the current spillway capacities of these dams. In this paper estimates of the design storm rainfalls for various return periods and also the PMP values for rainfall stations in the CHBP catchment have been computed for the three different durations of 1, 3 & 5 days. The maximum values for 1 day, 3 days and 5 days PMP values are found to be 730.08mm, 966.17mm and 969.0mm respectively at Station number 4513033 Gunung Brinchang. The PMP values obtained were compared with previous study results undertaken by NAHRIM. However, the highest ratio of 1 day, 3 day and 5 day PMP to highest observed rainfall are found to be 2.30, 1.94 and 1.82 respectively. This shows that the ratio tend to decrease as the duration increase. Finally, the temporal pattern for 1 day, 3day and 5 days have been developed based on observed extreme rainfall at station 4513033 Gunung Brinchang for the generation of Probable Maximum Flood (PMF) in dam break analysis. 1. Introduction Dams in different parts of the world are built for various purposes such as for fresh water supply, irrigation, hydroelectricity generation, flood control and for recreational activities. These dams however can break due to inadequate spillway design floods which can cause calamities in the downstream area. A survey of dam break data by Lemperiere (1993) showed that about 40 % of all dams break worldwide were because of inadequate spillway capacities. In the design of dams, the spillways are designed for the probable raingauges flood (PMF) derived from the probable maximum precipitation (PMP). Considering that many of the existing dams in Malaysia could be similarly unsafe based on hydrological conditions, a PMP study for Cameron Highlands- Batang Padang (CHBP) was carried out. The catchment has a series of 3 dams known as Sultan Abu Bakar, Jor and Mahang. The present study is devoted primarily to the estimation of the design storm rainfall values for different return periods including the PMP values for 3 different durations of 1, 3, and 5 days storms for rainfall

Hydrological assessment for mini hydropower potential at Sungai Pahang @ Temerloh

Sg Pahang at Temerloh was considered for assessment of hydropower potential using hydrological analysis method and hydrological model. The available data related to topography, soil, land use, weather and discharge pertaining to the study catchment were used to characterize the catchment. The characterization was required for water resources hence hydropower assessment. The hydrology of the study catchment was simulated through the model. This hydrological study is required due to the proposed mini hydroelectric power plant at Pulau Temerloh. It is essential to evaluate the existing river flow characteristic and to model the environmental flow assessment of the river. Two rainfalll stations, JPS Temerloh and Pintu Kawalan Paya Kertam Station are selected to develop the Rainfall Intensity Duration frequency (RIDF) Curve to determine the rainfall intensity of the area. Daily river flow were recorded at Sg Pahang at Temerloh and Sg Pahang at Lubok Paku were used to develop the Flow Duration Curve (FDC) to study the characteristic of Sungai Pahang flow. The 7 days low flow with 10 years return period (7Q10 low flow) was obtained using both Gumbel Method and Log Pearson Type III Method. The results from FDC shows that 50% percentage of time the Sg Pahang @ Temerloh is exceeded over a historical period is 400 m3/s and 50% percentage of time the Sg Pahang @ Lubok Paku is exceeded over a historical period is 650 m3/s. The required environmental flow are set to be 7Q10 low flow which is 64.215 m3/s for Sg Pahang at Temerloh and 79.24 m3/s for Sg Pahang at Lubok Paku. The results show the water resources are abundant and hence boost the mini hydropower potentiality at Sg Pahang.

Constructed Rain Garden Systems for Stormwater Quality Control under Tropical Climates

Malaysia has taken an integrated approach to manage storm water that is increasingly becoming a problem in big cities. Rain gardens are recommended as green technology for a new storm water management in Malaysia. The approach is applied in urban planning and design that integrates the total water cycle management into the development process areas. Rain gardens have been effective in reducing peak discharge and consistently reduce the number of storm water pollutants. This paper will examine some of guidelines, laboratory studies and field monitoring that shows great potential and benefit of rain garden. The preliminary results for rain garden performance were reported in this paper. The findings from this research will open avenues for researchers to advance the knowledge in rain garden systems to achieve the sustainable development in Malaysia.

Development of MSMA SME Design Aid Tools and Database System: Analysis and Design Stage

Rapid urbanization has many negative effects on environment such as deterioration of water quality contributed by pollution. In terms of stormwater management, even with the introduction of Manual Saliran Mesra Alam (MSMA) in 2000 (Urban Stormwater Management Manual for Malaysia), numerous new technologies have yet to be examined in detail, especially the relationship between water quantity and quality. Implementation is based on the restoration and optimization of the ecosystem. In this study, it has been reviewed and introduced the MSMA software in regard to water quality and discharge analysis for the future study. MSMA SME Design Aid and Database System knowledge base consists of a compilation of information and data relevant to stormwater treatment including algorithm for components, available design standard, technical guidelines, components design, supplier contact information, and images of each components and drawings. MSMA SME Design Aid and Database System framework consists of four main modules: user requirement input, analysis and design phase, prototype phase and user testing. There are 28 main components which have important role for visualization of any given catchment such as rainfall data, green roof, bioretention, constructed wetland, porous pavement, rainwater harvesting system, grey water reuse system and checking tools items. Currently, the 4 key components, such as bioretention system, water quality volume, lined drain design and bridge afflux estimator, have been developed in this study. MSMA SME Design Aid and Database System is able to assist engineers and developers in terms of management and improvement of water quantity and quality entering urban rivers from urban regions. This system is also helpful when an expert-level judgment is needed repetitively for a large amount of cases, like in the planning of stormwater BMPs systems for an entire city catchment.

An Overview: Flood Catastrophe of Kelantan Watershed in 2014

One of the challenging topics in Malaysia is flood occurrence, which have important impacts in human life and socioeconomic subjects. Malaysia, periodically, have faced with huge floods since previous years. Kelantan river basin, which located in the northeast of Peninsular Malaysia, is prone to flood events in Malaysia. Kelantan River has been badly affected with flood during recent monsoon season on December 2014 due to heavy monsoons rainfall and climate change issues. In this study, available rainfall and water-level data are analyzed and presented based on the flood event on December 2014. Generally, the flood area affected includes the districts of Kota Bharu, Kuala Krai, Machang, Pasir Mas, Pasir Puteh, Tanah Merah, Gua Musang, and Tumpat at Kelantan State. In the northeast monsoon season, the Kelantan State suffers from two phase of flood. The first phase began on December 14–17, 2014, and the second phase occurred on December 20–24, 2014. A comparison between accumulated rainfall on December and whole year of 2014 at Gagau station shows that contribution of rainfall on December is roughly 50 % of all of 2014. Overview of water-level results at Kelantan watershed shows that all areas are involved with highest record in 2014 in comparison with previous decades except Golok area. Results of water-level ranges show that most of the parts of Kelantan watershed are involved with over danger values for flood in 2014, which Lebir and Kelantan rivers have high increasing. In conclusion, it is suggested that there is a need to have study on flood mitigation and recognition of critical hydrological phenomena for sustainable strategies in Kelantan watershed. Consequently, this research provides primary information as baseline study for upcoming research for water resource management projects.