PREFACE

The International Seminar on Water Related Risk Management, held in , from 15 to 17 July 2011 were attended by experts, Scientiest, Practitioners and Profesionals on water resources, Coastal and other related sectors.

The discussions of the seminar had covered the entire aspects of water related risk management including risks contained in flood/drought , coastal , groundwater and urban drainage as well as socio-econonic aspects, involving likely notified profesionals with numerous models, scientific and empirical deliberation, as well as field experience exposures.

The overall presentations, discussions and debates during seminar concluded that the outputs will undoubtedly contribute to remarkable concepts, strategies, lessons learned, and sharing of experiences on the water related disastrous phenomena and it’s risks, particulary on the enviromentally sound technologies and sustainable practices on the year to come. Based on this fact, I believe that the proceeding of this seminar will be valuable document in solving the problems of water related disaster and reducing the impact of water related risk.

I would like to thank the organizing committee, reviewer and writers, seniors and all members of HATHI for enormous supports to the seminar. May God bless you all.

Pitoyo Subandrio

Chairman, The Organizing Committe July 17th, 2011

iii iv Table of Contents

Page Flood, Drought, Rainfall and Environment 1. Water Trap Series as an Integrated Approach in Flood and Drought Control (Case 1 Study Mbay City, Aesesa District, Nagekeo Regency, NTT Province, Indonesia) (Susilowati) 2. Hydraulic Modeling of Jatiluhur Morning Glory Spillway 9 (Indratmo Soekarno, Agung Wiyono and Febya Nurnadiati) 3. The Impact of Mount Bawakaraeng’s Caldera Colapse on Bili-Bili Reservoir 17 (Suwarno HP, Haeruddin C. Maddi and Willem M) 4. Five Required Steps for Upper Citarum Flood Mitigation 27 (Isdiyana, Yanto Wibawa, Winskayati and Suhedi) 5. A Theoretical Study of Flow Characteristic Due to Wave Run Up - Run Down 35 (Oki Setyandito, Nur Yuwono, Nizam and Radianta Triatmadja) 6. Outline of Musashi Canal Rehabilitation Project 43 (Yuki Hachijo and Kazuhiko Nakajima) 7. Seismic Analysis of Barrages Against Large-Scale Earthquakes 50 (Jun Utsunomiya, Tomoo Kato and Yuriko Tsuchida) 8. The Effectiveness of Source Control Measures to Solve Flood Problems 59 (Case Study Upper - Citarum Watershed) (Dwita Sutjiningsih, Evi Anggraheni, Wisang Adhitya and Tito Latif Indra) 9. Modelling Spatial Flood Risk Due to Rainfall Variabilities 67 in Upstream Basin (Anik Sarminingsih, Iwan K. Hadihardaja, Indratmo Soekarno and M. Syahril B.K.) 10. Problem and Solution of Water Resources Conservation in Java Indonesia 75 (Achmadi Partowijoto) 11. Raingauge Network Evaluation Using Geostatistic in Tembagapura Papua 83 (Imroatul Chalimah Juliana, Harry Suryantoro and Budhi Setiawan) 12. Distribution Scenario of Rainfall to Control Excessive Discharge in River 90 (Sulad Sriharto, Suseno Darsono and Putu Eddy) 13. Development of Semi Distributed Rainfall-Runoff Model for Optimizing Flood Control 98 at Wonogiri Reservoir (R. Jayadi and L. Arlensietami) 14. Validation of Rainfall Disaggregation Model Using Bayesian (Par(1)24) Model Coupled 106 with Adjusting and Filtering Procedure (Entin Hidayah, Nadjadji Anwar, and Edijatno) 15. A General Procedure for Development of ITB-1 and ITB-2 Synthetic Unit Hydrograph 114 Based on Mass Conservation Principle (D.K. Natakusumah, Dhemi Harlan and Waluyo Hatmoko) 16. Reliability of Nakayasu Synthetic Unit Hydrograf in Various Watershed Area 123 (Ariani Budi Safarina)

v Page 17. The Impact of Rainfall Variability and Hydrological Regimes on Flood Frequency 131 (Dyah Indriana Kusumastuti) 18. Analysis of Rainfall Station Spatial Distribution Based on The Distribution of 137 Physiomorphydro Zone in West Java Province (Iwan Setiawan and Dede Rohmat) 19. Preliminary Assessment of Environmental Flow in Way 145 an Effort to Reduce Environmental Risk (Endro P. Wahono) 20. Longterm Simulation of Phythoplankton Dynamics by Object Oriented Model to 153 Control Eutrophication in The Jatiluhur Reservoir (Eko Winar Irianto, R. W. Triweko and D. Yudianto) 21. Pollution in Jatiluhur Reservoir A Time Bomb for Jakarta and West Java 161 (Rapiali Zainuddin)

Coastal Engineering and Sediment Transport 1. Computer Simulation Using Duflow for Designing Water Management Improvement at 167 Reclaimed Tidal Lowland Area of Primer 8 Telang I, South Sumatera (Momon Sodik Imanudin, Sukoco and A. Muis) 2. Integrated Coastal Vulnerability Assesment Model for Bali Island 175 (D.M. Sulaiman, R Wahyudi Triweko and Doddi Yudianto) 3. Low Crested Breakwaters Using Geotube as an Alternative Measures for Beach 183 Erosion Control (Case Study of Pasir Putih Beach, Anyer, Banten Province) (D.M. Sulaiman, M.E. Sudjana and B.S. Prasetyo) 4. Theoretical Approach of Geotextile Tube Stability as a Submerged Coastal Structure 191 (Chairul Paotonan, Nur Yuwono, R. Triatmadja and Bambang Triatmodjo) 5. Two Dimensional Physical Modeling of Sediment Loss Through a Submerged Coastal 199 Structure (Chairul Paotonan, Nur Yuwono, R. Triatmadja and Bambang Triatmodjo) 6. Mangrove Forestry and Fish Skeleton Type of Long Storage Structure as an Integrated Approach in Coastal Protection Against Sea Level Rise (Case Study in Mbay Lowland Rice Field, Nagekeo Regency, NTT Province, Indonesia) 207 (Susilawati and Baki Henong) 7. The Effect of Permeable Groin on Longshore Current 215 (Hasdinar Umar, Rifky Surya Pratama, Adi Surya Pranata, Nur Yuwono, Radianta Triatmadja and Nizam) 8. Tsunami Force on Elevated Buildings 223 (Radianta Triatmadja and Any Nurhasanah) 9. Performance of Groin Type-I and Type-L in Maintaining Shoreline Stability 230 (Oki Setyandito, Nizam, Nur Yuwono, Radianta Triatmadja and Khusnul Setia Wardani) 10. Analysis of Overflow Structure Dimension for Water Management in 238 a Tidal Lowland Area (Rosmina Zuchri, Budi Indra Setiawan, Dwi Setyawan and Soewarso)

vi Page 11. Study of Cyclone and Storm Surge Characteristics in Bay of Bengal 247 (Masaaki Sakuraba and Kazuhisa Iwami) 12. Water Level Control in Tidal Lowland Reclamation to Reduce Flood and Drought Risk 254 (A Case Study in West Kalimantan) (Nurhayati, Indratmo Soekarno, M. Cahyono and Iwan Kridasantausa) 13. Modeling of Water System Condition Due to Reclamation in Upland of Jakarta 261 (Ahmad Mukhlis Firdaus, Hernawan Mahfudz, Dhemi Harlan and Ahmad Syafii Maarif) 14. The Impact of Built Islands on Maximum Water Level at River Mouths in West Part of 269 Jakarta Coast (A.P. Rahardjo, D. Legono and A.P. Palenga) 15. Effectiveness of Filter Backwashing Against Accumulated Cohesive Sediment 276 (Budi Kamulyan, Fatchan Nurrochmad, R. Triatmadja and Sunjoto) 16. Dynamics of Debris Flow Features at Gendol River Before and After 2010 Mount 284 Merapi Eruption (Wasis Wardoyo, D. Legono, R. Jayadi and T.F. Fathani) 17. Development of Collaborative-Based of Lahar Flow Early Warning System for Code 292 River in Yogyakarta (D. Legono, I.E. Prabowo, T.F. Fathani, D. Karnawati, and A.P. Rahardjo) 18. The Influence of Scour and Impact Forces of Lahar Flow on Stability of River 299 Structures (D. Legono, B. Wignyosukarto and A. Saputra) 19. The Influence of Sediment Concentration on Settling Velocity 305 (Wati Asriningsih Pranoto) 20. A Numerical Study of Lateral Dynamics an Associated Transport of Find Sediment 311 in The Mahakam Estuary (Idris Mandang and Tetsuo Yanagi) 21. An Invisible Countermeasure for Flood Mitigation - “Dredging” in Jakarta Emergency 319 Dredging Initiative (JEDI) Project (Chih-Hsiung, Huang and Chien-Pang, Liu)

Urban Drainage and Water Supply 1. “Polder” Development in Indonesia Challenges for Urban Drainage Solutions 327 (Joyce Martha Widjaya) 2. The Study of Polder System on Marina Hai Lai Gates Using HEC - RAS 335 (Irpan Harahap, Dhemi Harlan and Hernawan M) 3. Hydraulic Evaluation of Pluit Polder System in DKI Jakarta Province 343 (Dhemi Harlan, Hernawan Mahfudz and Ika Agustin Ningrum) 4. Potency of Small Lake to Reduce Sunter Flood 351 (Trihono Kadri) 5. Water Supply Related Risk Management Lesson Learned from Municipal Water 355 Supply Company (Perusahaan Daerah Air Minum) (Ahmad Lanti)

vii Page 6. Study on Clean Water Provision for Inhabitants in Bunaken Island 363 (Tiny Mananoma, Lambertus Tanudjaja, Happy Mulya and Widandi Sutopo) 7. Study of Surface Runoff Sensitivity Due to Land Use Change in Small Urban Area 370 (Nursetiawan and Dita Wulandari) 8. Reinforcement Operation Against Large Earthquake on Large Scale Water Supply 377 Facilities (Koichiro Otagaki) 9. Estimation of Irrigation Crop Production Risk 385 (Widandi Sutopo and Dwi Priyantoro) 10. The Effect of Micro Water Management on Water Availability to Increase Rice 390 Plantation Index (P Simanungkalit, L. Budi Triadi and Maruddin Fernandus) 11. The Study of Farmers Role in The Study of Operations and Maintenance on Irrigation 399 District Area Bogor Sasak (Suardi Natasaputra, Dhemi Harlan and Gemilang) 12. Development of Water Stress Index to Assess Water Stress in Jakarta 408 (Firdaus Ali)

Social Economic and Management 1. Integrated Flood Management Model Engaging Stakeholders to Overcome 417 Institutional Problems in Jakarta (Emma Akmalah and Neil S. Grigg) 2. The Necessity of a Dynamic Risk Index Map of Relatively Safe Area During Chaotic 425 Situation of Mount Merapi Eruption (Darmanto, D. Legono, T.F. Fathani, R. Jayadi and A. Sudihatmono) 3. The Effect of Land Use Changes on Low Flow Characteristic in Ciliwung River 432 (Waluyo Hatmoko) 4. Traditional Wisdom of Local People Surrounding Bade Reservoir 440 in Water Resources Conservation Management (A Case Study From Klego District, Boyolali Regency, Central Java Province) (Rahardjanto) 5. Impact of Urbanization in Jabodetabek and It’s Countermeasures Jakarta 447 Comprehensive Flood Management (JCFM) (Takaya Tanaka, Makoto Yonekura and Tadafumi Sato) 6. Flood and Water Related Issues in The Upper Citarum River Basin and It’s Future 455 Perspectives (Kenichiro Kato, Mudjiadi, Kazunori Inoue, Hitoki Takada, Takashi Yuasa, Susumu Ishikawa, Mamoru Nakamura and Yasuhiko Morita) 7. Assessment of Urbanization Effect on Flood in Scarcely Gauged River Catchment 463 (Mohammad Farid, Akira Mano and Keiko Udo) 8. Gotong Royong in The Digital Age 471 (J.B. Wagemaker, Melanie Miltenburg, Meidityawati, Bevita D and M. Hartman)

viii Page 9. Enhancement of Public Awareness and Participation 478 on Integrated Water Resources Management (Achmadi Partowijoto) 10. Role of Public Participation in Flood Risk Management 486 (Hisaya Sawano) 11. Project Risk Management in Hydropower Plant Project 493 (A Case Study from The State-owned Electricity Company of Indonesia) (Sarwono HM and W Bernadi Sudirman) 12. Risk Assessment for Krueng Teunom Flood Management 501 (A. Masimin and Zouhrawaty A. Ariff) 13. Evaluation of Erosion Based on GIS and Remote Sensing 509 to Support Integrated Water Resources Conservation Management (Case Study Majunto Watershed, Bengkulu Province-Indonesia) (Gusta Gunawan, Dwita Sutjiningsih and Herr Soeryantono) 14. Water Related Risk Management in Walanae Cenranae River Basin 515 After Tempe Barrage Construction (Subandi, Thomas Raya Tandisau, Malik Dalih and Nizam Lebah) 15. Integrated Disaster Mitigation for Flash Flood (Banjir Bandang) in Indonesia 523 (Toshiyasu Ueno and Keiji Yoshida) 16. Design Flood Information System Development Using Spatial Model 531 for Disaster Mitigation (Yadi Suryadi, Dian Indrawati, Iwan K. Hadihardaja and Joko Nugroho) 17. Managing Stalemate in Dam Projects 539 (Machiko Higa)

ix Longterm Simulation of Phythoplankton Dynamics by Object Oriented Model to Control Eutrophication in the Jatiluhur Reservoir

E.W.Irianto1 , R.W. Triweko2 and D. Yudianto2 1Research Center for Water Resources Ministry of Public Works Bandung, West Java 40153 INDONESIA 2Department of Civil Engineering, Faculty of Techniques Parahyangan Catholic University Bandung, West Java 40123 INDONESIA E-mail: [email protected]

Abstract: A reservoir can be catagorized as a multi-purpose water resources infrastructure. Unfortunately however, many of the reservoirs in Indonesia are facing the problem of eutrophication which recently has become a global concern. This problem can be solved by technical measures that include an object oriented conceptual model carried out by Powersim software. This paper focuses on the numerical simulation of reservoir water quality dynamics in controlling eutrophication. The water quality parameters simulated include the parameters as prime cause of eutrophication such as total Nitrogen dan total Phosphorus, whereas eutrophication is indicated by the phytoplankton concentration. The simulation result show that remedication of Jatiluhur Reservoir can be done by an integrated method, i.e. reduction of internal and external loading mainly on Total Nitrogen and Total Phosphorus loadings. Internal loading of nutrients compound should be reduce about 50%, while the nutrients come from external loading, must be lowered to 90%.

Keywords: Eutrophication, chlorophil-a, phytoplankton,Jatiluhur Reservoir, Conceptual Model

INTRODUCTION Eutrophication is a gradual process of excessive increase of fertility in a reservoir due to nutrients compounds, particularly Nitrogen and Phosphorus. This process causes an overly growth of primary vegetation and aquatic plants. Balcerzak (2006) sets forth that an euthrophication process takes place in several years and is mainly caused by anthropogenic activities. The eutrophication process in the reservoir eco-system shall decrease significantly with the increase of nutrient loading carried by the reservoir inflow started at the mesotrophic phase up to the eutrophic phase and finally reaching the hyper-eutrophic phase. There are two types of nutrient pollution loading entering a reservoir, the point source and non-point source. Included in the non-point source is wastewater originated from agricultural land or run-off. Lee, and Jones (2007) denote that these two sources of nutrient pollution loading cause an excessive growth of algae population and It is significantly affecting to the dissolved oxygen concentration. Kemp (2009) on the other hand explains also that increase of nutrient loading shall increase not only the potential of harmful algae bloom but also anaerobic or hypoxia conditions at the bottom of reservoir. Vandijk et al., (1994) to Balcerzak (2006) indicate that low dissolved oxygen concentration and excessive phytoplankton growth may affect the decrease of reservoir ecosystem. Melendez, et al. (2009) explains that the potential of algae growth because of the increase of nutrient loading shall cause difficulties in reservoir recovery process from hyper-eutrophic to mesotrophic. Reservoir remedy through reduction of nutrient loading and increase of dissolve ed oxygen at reservoir bottom is therefore to be implemented. Melendez, et al. (2009), has also denoted that pollution loading dynamics because of discharge fluctuation and concentration has a great effect on the condition of reservoir trophication. Considering the obove conditions objective of the study is to indicate the effect of nutrient pollution load entering the reservoir water body cause the eutrophication dynamics. When the effects of decrease of pollution input loading have been identified, efforts of controlling reservoir eutrophication can be carried out.

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METODOLOGY This study is initiated with setting up an object oriented conceptual model to simulate the eutrophication dynamics in the Jatiluhur Reservoir. Analysis of input data included the water quality data causes eutrophication processes such as Total Nitrogen and Total Phosphorus in Jatiluhur Reservoir that has been polluted by reservoir inflow and waste of fish food. This model analysis is carried out by dynamic model and assisted with the “Powersim Constructor “software, mainly on external and internal loading.. So that, the results is the long-term estimation of phytoplankton dynamics affected by pollutant load reduction through an object oriented conceptual model.

LITERATURE REVIEW

Affect of Nutrient Loading to Eutrophication Eutrophication is caused by an excessive input of nutrients loading and has been studied for the determination of control strategy since 1970 (Paur, et al, 2008). Major nutrients, such as total Nitrogen and to Phospor are limitation factors for phytoplankton, whereas silica is the limitation factor for diatoms in reservoir bottom deposit. Therefore, indications of excessive algae growth are shown by change of species composition, aesthetic disturbances, bad odour and taste and the drastically oxygen decrease or anaerobic conditions. Nutrient loading affecting the reservoir eutrophication process composes generally of nitrogen and phosphor particulates which further may dissolve into Available Nitrogen and Soluble Reactive Phosphor used to proliferate Phytoplankton (Chapra,1996). However, the dynamics of phytoplankton and diatom proliferation is also limited by zooplankton and the plankton death rate.

Nutrient loading into reservoir indicated from various sources that is natural and cultural activities mainly from human activities. Whereas, because of the reservoir retention time, nutrient loading shall show the bio-chemical exchange, deposition and evaporation processes also used by aquatic biota. Carpenter,S (2005) explains that phosphor loading tends to deposit and accumulate in sediment and biota. However, according to a study conducted in Lake Michigan, 60 % of deposited phosphor shall re-enter to the water column (Pauer, et al, 2008). The entering and release of nutrient loading particularly phosphor shall cause eutrophication dynamics, which initiates microcystic toxin in the reservoir produced by Cyanobacteria (Brahmana, et al, 2002).

Thus, in order to prevent toxic substances in water bodies, especially reservoirs, Kiirikki,et al. (2001) suggested to reduce nutrient loading particularly phosphorous subtance flowing from catchment areas. Kiirikki,et al. (2001) also denoted that the reduction of phosphor loading, mainly come from catchment areas, could be done with improving the domestic waste treatment system, which can significantly decrease the intensity of algae growth including Cyanobacteria in the water bodies in Finland. However, the recovery time of an eutrophic reservoir by decreasing the nutrient loading in a reservoir is still difficult to be estimated.

Dynamic Simulation of Eutrophication Tangirala, et al. (2003) indicate that the dynamic simulation system is the concept based on the idea where dynamic interaction between elements of a system can be studied and their behavior showing the overall system. Forester (1961) to Tangirala, et al. (2003) explained that the main idea of a dynamic system model is to understand the behavior of a system by use of a simple mathematical structure. Huang and Chang (2003) indicated that the dynamic system can be applied in environmental issues by an object oriented simulation (Figure 1). Nirmalakhandan (2002) explained that the dynamic system model can be applied in both environmental and water resources issues particularly the water quality on a reservoir as illustrated in Figure 2.

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Figure 1 Components of the object oriented simulation model (Tangirala et al.,2003)

Figure 1 illustrates an object oriented dynamic model formed by model blocks comprising (1) Stocks ; (2) Flow; (3) Converter; and (4) Connector. Stocks are functioning as storage for tangible or intangible variables. Flow to model the flow of specific amount by time series. Whereas connectors are modeling the information flow of a certain variable, and the converter is the model of functional relationship of variables, for instance mathematics, logic or others. Table 1 shows a list of water quality components and the model used, and Figure 3 depicts a Phytoplankton object oriented dynamic model

Table 1 Water quality components and object oriented modeling Water quality component Category of object oriented modeling Lake and reservoir, retention pond, deposition, Stock pollution load River flow, pollution load Flow Mathematical relationship (discharge and Converter pollution load), decay process Catchment system, outlet Sources dan Sinks Functional relationship and correlation Connector Source: High Performance System (2000)

Figure 2 Phytoplankton growth dynamic process desribed by object oriented model (Gurung,P.2007)

RESULTS AND DISCUSSION The eutrophication conceptual model that is suitable to be applied in Indonesia has to consider a water quality model that can be measured, monitored and calibrated according to the Indonesian standard of water quality laboratory measurements. Water quality parameter standards that can be measured on site include Dissolved Oxygen, pH, temperature and transparency. Parameters measured in the laboratory taken from water samples may comprise suspended particles, Nitrogen compounds like ammonium, nitrite and nitrate; phosphorus compounds, dissolved phosphate or ortho-phosphate and the organic parameter, as BOD, as shown in Figure 3. While Figure 4 illustrates a conceptual model of water quality parameters initiating eutrophication processes that can be described as a causal-loop diagram of eutrophication dynamic process affected by nutrients and organics in reservoir.

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Figure 3 Conceptual model of parameters interaction initiating eutrophication process in a reservoir

Figure 4 Causal-loop diagram of water quality parameter affect to Phytoplankton growth

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Figure 4 indicates two positive loops that have a snow ball effect to the excessive phytoplankton growth process or eutrophication. First loop starts at the NH3 uptake by phytoplankton. Phytoplankton is decomposed into Detritus (C:N:P), N fractionized into N Organic, N-organic ammonifized into NH3, then NH3 is uptaken to Phytoplankton. Second loop denotes the ortho-phosphate uptake by phytoplankton. Phytoplankton is decomposed into Detritus (C:N:P) , Detritus-P fractionized into P Organic, then there is mineralization process of P-Organic into Ortho-phosphate and then Ortho- phosphate is uptaken to Phytoplankton. Thus, these two nutrients loops are main instigate the eutrophication reservoir problem.While, Figure 5 and 6 show slider control and detailed program for eutrophication dynamic simulation assisted with Powersim software. Constants used in the model are depicted in Table 3, and calibration is done by comparison of observed and simulation data (Figure 7). Observed data are taken from the 2009 phytoplankton data of the Jatiluhur Reservoir (Gunadi, 2010) Table 3 Constants used in the eutrophication dynamic model (Gurung, 2007) No Constant Value Unit 1 Monod nitrate nitrogen constant 0.001 mg/L N 2 Monod ammonia nitrogen constant 0.001 mg/L N 3 Monod phosphor constant 0.001 mg/L P 4 Ammonia preference factor 1.46 mg/L N 5 Optimum light intensity 250 W/m2 6 Optimum temperature 23 0C 7 Shaping factor as temperature limit 0.6 - 8 Temperature lowest limit 5 0C 9 Maximum growth rate 0.9 1/day 10 Grazing rate 0.265 1/day 11 Death rate 0.3 1/day 12 Respiration rate 0.1 1/day 13 Temperature coefficient for respiration 1 - Source:Gurung,2007 Simulation results of phitoplankton dynamic, affected by nutrients reduction, is illustrated in Figure 7 and 8. This simulation can be done by several scenarios, among others: without policy, reducing internal factors, reducing phosphor loading by 20% and reducing Total Nutrients by 60%, 80% and 90%. Results indicate that remedy of the Jatiluhur Reservoir should be done by integrated method i.e: (1) internal management of the reservoir environment and (2) reduction of external nutrien loading. Expectantly, internal management of reservoir environment can reduce the potential phytoplankton growth into 50%. This initiative has to be combined with the reduction of external nutrient loading at least 90%, in order to restore the Jatiluhur Reservoir to be an oligotrophic-mesotrophic category.

Figure 5 Slider control for dynamic simulation of hytoplankon growth in Jatiluhur Reservoir

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Figure 6 Diagram of the object oriented dynamic simulation program of phytoplankton growth affected by water quality parameters

Figure 7 Comparison of simulation results and observed data

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(a) (b)

(c) (d)

(e) (f)

Figure 8 Dynamic simulation of Phytoplankton in Jatiluhur reservoir (a) without eutrophication control in short-term; (b) without eutrophication control in long-term; (c) internal control 50% and external reduction of P loading 20%; (d) internal control 50% and external reduction both TN and TP loading 60%; (e) internal control 50% and external reduction both TN and TP loading 80%;(e) internal control 50% and external reduction both of TN and TP loading 90%.

CONCLUSION Results of the literature review and tests on the use of an object oriented dynamic conceptual model show that eutrophication in a reservoir can be controlled by reducing 90% of external nutrient loading of 90% in combination with reservoir internal environmental conditions.

ACKNOWLEDGMENT High appreciation is given to Dr.Arie S.Moerwanto, director of the Research Center for Water Resources for his assistance and the opportunity he has given to the writers for writing this paper.

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Melendez, W., M. Settles, J. J. Pauer, and K. R. Rygwelski. (2009). A High-Resolution Lake Michigan Mass Balance Water Quality Model. U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid- Continent Ecology Division, Large Lakes Research Station, Grosse Ile, Michigan. EPA/600/R- 09/020, 329 pp. Mendiondo & Tundisi (2007). Eutrophication in Lakes and Reservoirs: Remedial Measures and Prospective Research. In International Colloquium of Lakes and Reservoirs, 2007, Putrajaya, Malaysia. Key-note paper. Putrajaya: NAHRIM / ASM, National Hydraulic Research Institute of Malaysia. Nirmalakhandan,N (2002) Modelling Tools for Environmental Engineers and Scinetist,CRC Press, Boca raton,USA Pauer, J.J., A. Anstead, W. Melendez, R. Rossmann, K.W. Taunt, and R.G. Kreis. (2008). The Lake Michigan eutrophication model, LM3-Eutro: Model development and calibration. Water Environ. Res. 80:853-861. Pauer, J.J., K. Taunt, W. Melendez, R.G. Kreis, and A. Anstead. (2007). Resurrection of the Lake Michigan eutrophication model, MICH1. J. Great Lakes Res. 33:554-563.