Implementation of Urban Stormwater Management

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Implementation of Urban Stormwater Management Practices in Malaysia *

Husna Takaijudin1, Ahmad Mustafa Hashim1, Kalaikumar Vallyutham1, Ainil Husna Ahmad Shahir2, Abdul Halim Ghazali3 1

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Lecturer, Department of Civil Engineering, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak, MALAYSIA. Final Year Student, Department of Civil Engineering, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak, MALAYSIA. 3 Associate Professor, Department of Civil Engineering, Universiti Putra Malaysia, Serdang 43400, Selangor, MALAYSIA Tel: 05-3687354 Fax: 05-3657616 *Corresponding author, e-mail: [email protected]

Absract-New urban development area has been recognized as the main national problem when dealing with stormwater runoff due to the reduction on pervious area and creating flooding problem. The conventional engineering method is not effective because it is insufficient to cater higher amount of runoff discharges from new development area. Besides, it will create the significant problem such as flooding, surcharge and channel system blockage. Therefore, the ‘environmental friendly’ approach should be applied when dealing with storm water runoff. The storage facilities are integrated in the drainage network design to cater the volume of runoff from new urban development area. This paper reviews current approach and case studies related to the stormwater management (SWM) in urban areas mainly in Malaysia. It also describe on the development of the urban drainage and storage system design methods. Finally, it concludes for further research needs. Key words: urban development, stormwater management, flooding, drainage system

I. INTRODUCTION Malaysia has experienced major floods since 1920 [1]. He also stated that the flood attacked Kuala Lumpur and other states in January 1971. It had caused the loss of properties up to RM 200 million and 61 people died. Additionally, the most recent flood in December 2006 and January 2007 in Johor, the total cost of flood disaster has estimated to be RM 1.5 million. This flood affected around 110,000 people lost their home and sheltering in relief centers and 18 people were died [1]. Nowadays, flash flood occurs in the cities and towns. This is caused by the sprawl urban development in these particular areas. As these urban areas have emerged, it creates more impervious areas such as in Kuala Lumpur, Pulau Pinang and Johor Bharu in Malaysia. In addition, the amount of impermeable areas will increase for many purposes of landuse. The transitions from forest and open spaces areas to the commercial and industrial areas have caused significant changes directly to the local ecosystem [2]. In other words, the natural processes i.e. the physical, biological, chemical processes have been disturbed due to the unplanned development. In hydrological perspectives,

the important physical processes in hydrological cycle have been disrupted by this kind of development [2]. The surface runoff may change its flow path significantly due to the land characteristics are always changed [3]. The increased of impervious areas do not allow infiltration process to the ground. Development also cut trees and vegetation where the transpiration process will be eliminated. It will cut the natural vegetation. This will result the rise of surface runoff volume and create flooding problem. The drainage system is very important infrastructures to cater the flow of runoff from catchment areas. However, drainage failure will lead to surcharged and flooding problem as well. Most of drainage facilities and silt trap did not maintain very well. It may create significant problem such as blockage, pipe leakage etc. It also increases the volume of sediment in the system. Many parties who are involved in the development program should concern the effect of development to the environment. The Government agencies have provided guidelines for development purposes and considering the environment aspects. Engineers must be creative by applying soft approach e.i. towards natural approach in the design and construction aspects. Municipal planning is undertaken to set up the form and extent of urban land use within a catchment and to meet the constraints of sustainable flows and constituent loads specified in the catchment management plan. The metropolitan area (or the urban part of the municipality) is one of the significant land uses within the catchment. Whether a plan covers a municipality or the metropolitan area depends mainly on the responsibilities for stormwater management within each State and Territory. This paper reviews current practices of urban stormwater management in Malaysia and other countries. II. LITERATURE REVIEW A. History of Urban Drainage System Design Methods Initially, peak discharges is the main variables of hydrology in drainage system design which related to the highest water surface level during storm event [3]. It can be defined as the maximum volume flow rate that passes a

2 particular site during a storm event, and it has units of volume per time, such as cubic meter per second (m3/s) and cubic feet per second (ft3/s). John Roe carried out the first analysis in 1852. He published an observation‟s record for London sewers. In 1857, Hawksley built analytical expressions to Roe‟s data to make a correlation between the magnitude of peak discharge and the drainage area [3]. Over the half century that followed, Hawksley‟s formula produced a generation of pseudo empirical equations of peak flow estimation. However, he particularly did not consider meteorological variables such as rainfall intensity and frequency of estimated peak discharges. In 1879, Major E.T.C Myers developed the Myers formula which computes the area of waterway, Ac in (1). The area was independent of landuse and rainfall, although coefficient Cm corresponded to the rainfall intensity. Nevertheless, it has limited to small catchment areas. Myers was the chief engineer of the Richmond, Fredericksburg, and Potomac Railway in Virginia. Ac = CmA0.5

(1)

where Ac is the area of the waterway in acres, Cm is a coefficient which reflects the slope of the drainage area, and A is the drainage area in acres. A Swiss Hydraulic Engineer, A. Burkli-Ziegler introduced The Burkli-Ziegler Formula (2) in 1880. He computed the unit discharge (ft3/sec/acre), qm using qm = Cbi (S/A)0.25

(2)

in which Cb is a runoff coefficient, i is the average rainfall intensity (in/hr) during heavy rainfall, S is the average ground slope (ft/1000 ft), and A is the drainage area in acres. Cb depends on the landcover, with special emphasis on the relative imperviousness. Professor A.N. Tablot from the University of Illinois carried on the studies on the determination the drainage areas in 1887. He presented the Talbot Formula (3) which as generated from the Burkli-Ziegler. a = CtA0.75

(3)

where a is waterway cross-sectional area in ft2, Ct is a runoff coefficient, and A is the drainage area in acres. Emil Kuichling in the United States was a pioneer in establishing the Rational Method in 1889 along with Mulvaney (1850) in Ireland [3]. Lloyd-Davies (1906) in Wales stated that rainfall intensity is one of the significant factors that allowing for the specific significant factor to the peak discharge [3]. The concept of rainfall intensity and intensity-duration-frequency (IDF) curves established at that time has been used until the today for drainage design practice. There are two important issues highlighted that arise from the application of the Rational Method and IDF curve [4]:

1.

The runoff characteristics are related to the meteorological characteristics. 2. Use of IDF curves implicitly characterizes a rainfall hyetograph of given duration as a rectangular trace of rainfall with a constant intensity. In 1932, Sherman introduced the unit hydrograph when he realized that Rational Method is unable to generate the full shape of a runoff hydrograph where the initial method was intended to estimate discharge only at one point in time [4]. B. The Importance of Stormwater Management (SWM) Stormwater management has a little interest compared to wastewater and water resources management due to less pollution in a longer period [5]. Traditionally, most of the countries had applied the conventional drainage system where all the surface runoff must be discharged directly to the nearest river or stream. The practice of urban drainage has been traced back to some of the earliest recorded histories of mankind. This practice of conveyance of stormwater from urban areas to safer places will involve engineering solutions for the reduction of flood damage potential and water pollution [4]. The open drain and culvert are commonly used over the years in Malaysia to cater the flow directly to the river. However, as the urbanization raise rapidly, the channels capacity insufficient to cater to high volume of runoff before the flows entering to the receiving watercourse. This physical approach is not feasible because it requires the removal of existing drain and extra excavation to install the new one. It might involve millions dollars for installation and maintenance costs. In addition, the water is not treated well by applying this conventional method. The runoff may have polluted substances that conveying through the system. Hence, it will lead to have pollution at the downstream i.e. rivers and streams. Nowadays, many institutions, NGOs and government agencies are concerned on the implication of climate change. Most of the human activities such as construction, logging, and industries should not go against environment to achieve the healthy and safety nature. For this reason, the „environmental friendly‟ approaches should be applied when dealing with stormwater runoff. Many countries implement this approach such United Kingdom, Europe countries, United States and Malaysia. This is the new direction for stormwater management system towards the sustainable development. Stormwater management also attempts to mitigate harmful effects of land development [3]. The policies of stormwater management have been introduced to limit the runoff characteristics after development to those that existed prior development. It is required to merge the storage and treatment facilities in the drainage system network to control the runoff from new development area before the water is allowed to enter the nearest river or stream.

3 C. Types of BMPs Systems Sustainable Urban Drainage System (SUDs) has been implemented in UK which associated to the stormwater management system. Other countries such as US and Australia carry out similar concept with different names. It is called Low Impact Development (LID) in US and Water Sensitive Urban Design (WSUD) in Australia [6]. The goals are to encourage more pervious area and raise the infiltration of rainfall [6]. In Malaysia, DID also introduce the same practices given in the Urban Stormwater Management Manual for Malaysia (MASMA) to become an effective system in order to maintain the environment quality standards for the next generation [7]. They also provide a set of guidelines for new development in Malaysia which adopting natural process solutions for stormwater treatment. This approach is more environmentally-friendly and capable of being integrated with other drainage system facilities. There are several natural techniques that have been introduced for stormwater treatment. Initially, the sourcecontrol techniques promote the natural process i.e. the infiltration and storage at the initial stage. This method can minimize the runoff discharge from contributing areas. Porous pavement can be applied at the parking space usually in residential commercial and industrial areas. The porous materials such asporous concrete, gravel and brick block permit runoff infiltrate to the ground. Other example is infiltration basin and trench which allowing the runoff infiltrate to the ground through the vegetated drain. They also allow the underground temporary storage before it convey to the downstream. In US, researchers were addressed the advantages on these techniques by decreasing impervious areas and promoting infiltration [8]. The control-at-source techniques have been applied in some region such as Prince Georges County and Maryland [9]. Secondly, the permeable conveyance system likes swales are commonly used at the roadways that have been found in US. It is the shallow channel with grassed depression covering the side slops and bottom. The grass surfaces act as the filter to trap debris, suspended solids, oil and sediments. It also promotes the infiltration and storage process. Thus, it will reduce the volume of runoff before entering the stream through the conveyance system. However, it has limitations

when providing swale system. It is not performing well during the large storm event due to the shallow depth of its channel and the infiltration process is slow and allow flood problem. It is also impractical in flat areas, steep topography and poor drained soil. Swale can treat the runoffs through the storage and infiltration process as well. The third approach is passive treatment system. This technique implements pond system. The retention ponds have maintained permanent pool of water throughout the year. Regarding to the current practice in Malaysia, the developer and engineers prefer this method to handle runoff from development activities. They can upgrade abandoned pond to cater the runoff from residential areas. Most of the natural processes can be adopted using this kind of method. It functions as storage and releases the flow gradually through the outlet control structure. In addition, the detention pond has commonly been found to perform better for highway and road runoff treatment [10]. Also, it also has the multifunctional purpose of both reducing the spread of pollutants and reducing the hydraulic pressure on the downstream pipe systems and waterways. Researchers suggested that a detention pond can be very efficient in the removal of the pollutant concentration such as Total Suspended Solids (TSS) and metal particles [11]. In Sweden, investigator carried out the study on water quality performance and the presence of sediment for the detention pond system [12]. Table 1 gives the summary of water quality data for detention pond in Vallby, Sweden. In some area in US, they preferred the integration of conveyance system and detention pond to optimize the contaminants and hydrologic alteration. However, the performance of the system is remain less effective that the others [6]. The alternative system is the retention pond which can function as a permanent pool all the time. It has a long retention time which results in a high performance in removing pollutants through the infiltration and settlement. In addition, this technique creates a wildlife habitat and is suitable for development as a recreational area. However, the unavailability of land will limit the pond size. The pool also promotes the breeding of mosquitoes and other harmful insects [13].

TABLE 1: POLLUTANT REMOVAL FOR A DETENTION POND IN VALLBY, SWEDEN [12]. Parameter

Total N (mg/l)

Total P (mg/l)

COD (mg/l)

Total Cr (μg/l)

Total Cu (μg/l)

Total Pb (μg/l)

Total Zn (μg/l)

Mean (out) Median (out) Reduct. Efficiency Min- Max No. of samples

1.0 0.8 67% 0.67-1.7 4

0.03 0.03 78% 0.02-0.06 4

2.9 3.5 92% 0.8-3.8 4

4.6 2.5 52% 2.0-21.0 10

10.4 9.8 51% 6.1-22.0 10

6.8 5.0 26% 3.1-21.0 8

52.3 7.8 84% 3.6-290 9

D. The Overview of SWM Practices in Malaysia Development in Malaysia has progressed rapidly since independence in 1957. The economy has shifted from being

the agriculture-based to industry-based which has resulted in population growth in the urban areas. The problems arise when the urban areas become increasingly impermeable, and

4 disturb the ecosystem. The growth of impervious areas will block the natural purification process and water storage. In other words, such development brings significant effect on the hydrologic and hydraulic characteristics of watershed.Thus, it is not surprising the flash flood occurs in urban areas in Malaysia and the problem is becoming worse and more frequent from year to year. In Malaysia, the most common drainage applied over the years is the open channel i.e. the open drainage system. This practice has been adopted in Malaysia as well to mitigate the flash flood problem in urban areas. It is referred to the first urban drainage system manual “Planning and Design Procedure No.1: Urban Drainage Design Standard and Procedure for Malaysia” in 1975. However, the researcher observed that the solution is not the best approach for future and it may create the flash flood at the downstream of catchment [14]. Some of the new developments in Malaysia have adopted pipe conduits as an alternative to the open drainage system to carry the stormwater runoff to the receiving watercourse. However, these systems also promote river pollution and have a significant impact on public health as well. Therefore, the Department of Irrigation and Drainage DID Malaysia which is the Government‟s representative has taken a comprehensive approach by introducing the New Urban Drainage System Manual entitled “Stormwater Management Manual for Malaysia” (Manual Saliran Mesra Alam or MASMA) that became effective in January 2001. These guidelines set up a new philosophy (for Malaysia) which is “source control techniques” in order to minimize the runoff flow rate from the contributing area. This differs significantly from the previous procedure that applied the concept of “rapid runoff discharge” [15]. This manual involves the application of Best Management Practices (BMPs) to control stormwater in terms of quantity and quality runoff to achieve zero development impact contribution [16]. The main objectives of these guidelines are to provide guidance to all regulators, planners and designers who are involved in stormwater management. It identifies a new direction for stormwater management in urban areas in Malaysia [7]. In Malaysia, the wetland and the lake as a storage and purifier of stormwater has been adopted in the Federal Government Administrative Centre Putrajaya [16]. In addition, another good example of Best Management Practices (BMP‟s) in Malaysia is the implementation of a Bio-Ecological Drainage System which has applied vegetated swale, dry pond, wet pond, and detention pond and wetland techniques. The quality of stormwater has been tested. The performance of water quality is in the range of Class I to Class III based on Water Quality Index (WQI) [17]. This project covers 300 acres at the Engineering Campus, Universiti Sains Malaysia (USM), Nibong Tebal, and also at USM Pulau Pinang. It was completed in December 2002 [18-19]. The performance of the existing dry detention pond for medium size housing development using Infoworks

Collection System (InfoWorks CS) has been investigated (Liew et al, 2009). The case study is located at Kota Damansara, Selangor [20]. They recommended that future development should consider the effect of landuse change in the design phase. This is because the runoff conveys rapidly to achieve maximum flow under the landuse change scenario by 80 minutes for 50 years ARI and 70 minutes for 100 years ARI. However, this pond could perform up to 100 years ARI of design rainfall in current condition and allowed future residential development [20]. Public Work Department of Malaysia (PWD) also has several infrastructure project which adopting MASMA practices [21]. One of the projects was for the Special Malaysia Disaster Assistance and Rescue Team (SMART) which built a drainage system network and a detention pond. The site is located at Pulau Meranti, Sepang District,Selangor. The site is adjacent to Kampung Pulau Meranti. It is about 20 km from Sepang Town, and 5 km from Cyberjaya. The total area of the project is about 24 hectares. This practice is to protect the adjacent village of Kampung Pulau Meranti from flooding problem. The drainage system is connected to the detention pond. Surprisingly, there is no river near the site. Thus, the flows were directed to the existing main earth drain by adopting culverts as the primary outlet control structure. They found that the peak discharge before and after development is approximately similar by integrating the storage system [21]. This project was completed in 2008 However; this project is recommended to have the assessment on the water quality. III. FUTURE RESEARCH NEEDS Based on the extensive review of theory and case studies, the best practices of urban stormwater management need to be identified. It will be based on the suitability of the local areas, the rainfall characteristics and types of development for the particular areas. Some of the natural processes have adopted for storage and treatment purposes. However, the effectiveness of these methods needs further investigations to tackle the flash flood problem and to meet the water quality standard. Further researches will be focused on the assessment on the detention pond which is the main practice particularly in Malaysia. It is noticed that the developers prefers to propose this kind of techniques due to lower cost of construction and maintenance. Besides, there are many aspects that we need to consider during design and analysis stage for example the assessment on the quantity of volume flow rate, the channels and storage size and the quality of the water by using the available latest computer modeling. REFERENCES [1] Sulaiman, A.H., “Flood and Drought Management in Malaysia” Speech text, Ministry of Natural Resources and Environment, June 2007, pp. 4-5. [2] Davis, A.P. Mc Cuen, R.H., Chapter 1 Introduction, Stormwater Management for Smart Growth, Springer, US, 2005 pp. 1-5.

5 [3] Mc Cuen, R.H., Chapter 7 Peak-Discharge Estimation, Hydrologic Analysis and Design, 3rd Edition, Pearson Prentice Hall, New Jersey, 2004;pp. 361-382. [4] Adam, B.J., Papa, F., Urban Stormwater Management Planning with Analytical Probablistics Models; John Wiley Sons, Inc; 2000. [5] Chouli, E., Aftias, E., Deutsch, J.C., “Applying stormwater management in Greek Cities: Learning from the European experience.”, Desalination, Elsevier, Greece, 2007, pp. 61-68. [6] Roy, A.H., Wenger, S.J., Flecther, T.D., Walsh, C.J., Ladson, A.R., Shuster, W.D., Thurston, H.W., Brown, R.R., “Impediments and Solutions to Sustainable, Watershed-Scale Urban Stormwater Management: Lesson from Australia and the United States.”, Environmental Management, Springer Science+Business Media, 2008, 42, pp. 344-359. [7] DID, Urban Stormwater Management Manual for Malaysia (MASMA), 2000, 4-7. [8] Schueler T.R., “The Importance of Imperviousness”,Watershed Protection Techniques, 2006, 132, pp. 89-96. [9] US EPA ( US Environmental Protection Agency), “Low Impact Development- a literature review” (EPA-841-B-00-005), Office of Water, EPA, Washington, DC, 2000. [10] Starzec, P., Lind, B.B., Lanngren, A., Lindgren, A.S., and Svenson, R.N., “Technical and Environmental Functioning of Detention Ponds For The Treatment of Highway and Road Runoff”, , Water, Air, and Soil Pollution Paper, Sweden, 2005, 163,pp.153–167. [11] Hossain. M.A., Alam. M., Yonge D.R., Dutta. P., “Efficiency and Flow Regime of a Highway Stormwater Detention Pond in Washington”, Water, Air, and Soil Pollution Paper, USA; 2005, 164, pp.79–89. [12] Farm, C. “Evaluation of the accumulation of sediment and heavy metals in a storm-water detention pond. Water Science and Technology, 2002, 45 (7), 105-112. [13] Vollersten, J., Astebol, S.O., Coward, J.E., Fageraas, T., Madsen, H.I., Nielsen, A.H., Hvitved-Jacobsen, T., “Monitoring and Modelling the Performance Runoff in Cold Climates of a Wet Pond for Treatment of Highway”, Highway and Urban Environment: Proceedings of the 8 th and Urban Environment Symposium, 2007, 499-509.

[14] Abdullah, R., Zakaria, N.A., Ab. Ghani, A., Sidek. L.M., Ainan, A., Wong, L.P, et al. “BIOECODS Modeling Using SWMM”, Advances in Hydro-Science and Engineering, 2002, 5. [15] Sidek, L.M., Ab. Ghani, A., Zakaria, N.A., Desa, M.N., Othman, N., et al. “An Assessment of Stormwater Management Practices in Malaysia”, BuletinJurutera; January, 2006. [16] Zakaria, N.A., Ab. Ghani, A., Sidek. L.M., Ainan, A., et al.. “MSMAA New Urban Stormwater Management Manual for Malaysia”, Advance in Hydro-Science and Engineering, 2002, 4. [17] Ayub, K.R., Mohd Sidek, L., Ainan, A., Zakaria, N.A., Ab. Ghani, A., Abdullah, R., “Storm water treatment using Bio-Ecological Drainage System”, International Journal River Basin Management, International Association of Hydraulic Engineering and Research (IAHR), 2005, 3(3), pp. 215-221. [18] Ab. Ghani, A., Zakaria, N.A., Abdullah, R., Yusof, M.F., Mohd Sidek, L., Kassim, A.H., and Ainan, A. “Bio-Ecological Drainage System (BIOECODS): Concept, Design and Construction,” 6th International Conference on Hydroscience and Engineering (ICHE-2004), Brisbane, Australia, May 30 – June 3, 2004. [19] Zakaria, N.A., Ab. Ghani, A., Abdullah, R., Mohd Sidek, L., Kassim, A.H., and Ainan, A. “Bio-Ecological Drainage System (BIOECODS) For Water Quantity and Quality Control,” International Journal River Basin Management,International Association of Hydraulic Engineering and Research (IAHR), 2003, 1(3), pp. 237-251. [20] Liew, Y.S., Ab. Ghani, A.., “Performance of Stormwater Drainage System through Dry Detention Pond for Medium Size Housing Development using Infoworks CS (CaseStudy:Kota Damansara,Selangor, Malaysia)”, 8th International Conference on Urban Drainage Modelling, Tokyo, Japan, 7-11 September 2009. [21] Jabatan Kerja Raya. Cadangan Pembinaan Markas Pasukan Mencari dan Menyelamat Khas Malaysia (SMART) dan Institut Pengurusan dan Bencana (IPKBN) di Sepang, Selangor, Laporan Sistem Perparitan, Kuala Lumpur. 2006.