REFERENCES Calibration of Monthly Spatial Runoff from the Root Zone using Water Balance Method (A Case Study in Cicatih Watershed, Sukabumi, West Java)

17

V. CONCLUSIONS AND SUGGESTION

5. 1 Conclusions The calibration procedures consist of two steps parameters optimization. Firstly, optimize the parameters c and WHC according to the criterion RE. Secondly, optimize the parameter WHC again according to the criterion R 2 , with the value of c obtained in the first step. The results of monthly spatial runoff presented in the article had proved to be quite efficient of describing the monthly runoff with R 2 value of 66.15 and relative error RE of 1.4 . The method can easily be incorporated in water resources planning program to estimate monthly runoff in the Cicatih watershed because of their simplicity and efficiency of performance. The implication of the study is to describe the comparison between monthly spatial runoff of the 1999 land uses pattern and the recent year land uses pattern. The result of spatially distributed runoff clearly indicated the influence of rainfall, land cover types, and water holding capacity WHC. However, the monthly distibuted runoff was only affected by the rainfall. The runoff distributions of subwaterheds showed that runoff varied from 263 mm in Ciheulang subwatershed to 26 mm in Cikembar subwatershed. The monthly runoff distribution of Cicatih watershed showed that the lowest runoff was 35 mm occurred in September and the highest runoff was 260 mm occurred in January. The spatial runoff distribution in Cicatih watershed reflected that during the high rainfall period in Cicatih, maximum runoff could be found in the forest areas 286 mm and followed by cropland areas 269 mm. And minimum runoff was 251 mm occurred in settlement areas. In the low rainfall period, maximum runoff 109 mm was found in forest areas. Minimum runoff was 0 mm occured in the settlement areas, followed by cropland areas 5 mm around the mountain Salak and mountain Pangrango. It was found that runoff increased with significant incresing rainfall, following a positive linear function.

5. 2 Suggestion

For future applications, it is suggested to consider the rainfall-runoff pattern in water resources planning program Cicatih Watershed, Sukabumi, West Java.

VI. REFERENCES

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Model spasial dinamik pendugaan surplus air permukaan menggunakan metode neraca air [Skripsi]. Bogor: Fakultas Matematika dan Ilmu Pengetahuan Alam, Institut Pertanian Bogor. Ladekarl UL. 1998. Estimation of soil water balance in a Danish oak stand from measurements of soil moisture using TDR. Forest Ecology and Management. 104: 227-238. Lewis D, Singer MJ, Dahlgren RA, Tate KW. 2000. Hydrology in California oak woodland watershed: a 17-year study. J. Hydrol. 240: 106-117. Li XY, Liu LY, Gao SY, Shi PJ, Zou XY, Zhang CL. 2005. Microcatchment water harvesting for growing Tamarix ramosissima in the semiarid loess region of China. Forest Ecology and Management. 214: 111-117. Lull HW. 1964. Ecological and Silvicultural Aspect. In: Chow VT, editor. Handbook of applied Hydrology. New York: McGraw Hill. Madsen H. 2000. Automatic calibration of a conceptual rainfall-runoff model using multiple objectives. . J. Hydrol. 235: 276-288. Maklouf Z and Michel C. 1994. A two- parameter monthly water balance model for French watersheds. J. Hydrol. 162: 299-318. Mehrotra R and Singh RD. 1998. The influence of model structure on the efficiency of rainfall-runoff models: A comparatuive study for some catchment of central India. Water Resour Manage. 12: 325-341. Nash JE and Sutcliffe JV. 1970. River flow forecasting through conceptual models. J. Hydrol. 10: 282-290. Ollinger SV, Aber JD, Federe CA. 1998. Estimating regional forest productivity and water yield using an ecosystem model linked to a GIS. Landscape Ecology. 13: 323-334. Pawitan H, Taufik M, Herawati S, Kurnianto S, Askari M. 2005. Biophysical indicators of watershed functions: case study of Cicatih Basin- Sukabumi. Hydrometeorology Laboratory, Departement of Geophysics and Meteorology, FMIPA-IPB. Putty MRY and Prasad R. 2000. Understanding runoff processes using a watershed model – a case study in the Western Ghats in South India. J. Hydrol. 228: 215-227. Putuhena WM and Cordery I. 2000. Some hydrological effects of changing forest cover from eucalypts to Pinus radiata. Agricultural and Forest Meteorology. 100: 59-72. Starsser U and Mauser W. 2001. Modelling the spatial and temporal variations of the water balance for the Weser catchment 1965-1994. J. Hydrol. 254: 199-214. Sun G, McNulty SG, Shepard JP, Amatya DM, Riekerk H, Comerford NB, Skaggs W, Swift Jr. L. 2001. Effect of timber management on the hydrology of wetland forest in the southern United States. Forest Ecology and Management. 143: 227- 236. 19 Sun G, McNulty SG, Amatya DM, Skaggs RW, Swift Jr. LW, Shepard JP, Riekerk H. 2002. A comparison of the watershed hydrology of coastal forested wetlands and the mountainous uplands in the Southern US. J. Hydrol. 263: 92-104. Thornthwaite CW, Mather JR. 1957. Instruction and Tables for Computing Potential Evapotranspiration and Water Balance. Publication in Climatology. 103. Vandewiele GL, Xu CY, Ni-Lar-Win. 1992. Methodology and comparative study of monthly water balance models in Belgium, China and Burma. J. Hydrol. 134: 315-347. Vertessy RA, Watson FGR, O’Sullivan SK. 2001. Factor determining relations between stand age and catchment water balance in mountain ash forest. Forest Ecology and Management. 143: 13-26. Xiong L and Guo S. 1999. A two-parameter monthly water balance model and its application. J. Hydrol. 216: 111-123. Xu CY. 1997. Application of water balance models to different climatic regions in china for water resources assessment. Water Resour Manage. 11: 51-67. Xu CY. 1999. Estimation of parameter of a conceptual water balance model for ungauged cathments. Water Resour Manage. 13: 353-368. Xu CY and Singh VP. 1998. A review on monthly water balance models for water resources investigation and climatic impact assesment. Water Resour Manage. 12: 31-50. APPENDICES Appendix 1. Map of Soil Types in Cicatih watershed Appendix 2. Mean of monthly temperature during 1988-1999 periods Year Month 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Average Jan 25.5 24.9 24.0 25.0 25.0 25.0 25.1 25.1 24.5 25.2 26.9 25.2 25.1 feb 25.5 24.5 25.5 24.5 25.0 24.5 24.9 24.9 25.0 25.0 25.9 24.9 25.0 Mar 26.0 25.0 25.0 25.5 25.5 24.4 25.5 25.5 25.6 25.8 26.8 25.2 25.5 Apr 26.0 25.0 26.0 25.5 25.8 26.2 26.1 26.1 27.6 26.0 26.8 25.8 26.1 May 26.5 24.5 26.0 26.0 26.0 26.2 26.3 26.3 28.2 26.3 27.1 26.0 26.3 Jun 25.4 25.0 25.5 25.5 25.5 25.8 25.7 25.7 26.0 25.7 26.6 25.7 25.7 Jul 25.4 25.5 25.5 24.5 25.0 25.5 25.3 25.3 25.7 24.9 26.0 25.2 25.3 Aug 26.0 25.0 25.0 24.5 24.5 25.0 25.3 25.3 25.5 25.6 26.4 25.5 25.3 Sep 25.5 25.0 25.5 25.5 25.5 25.0 25.6 25.6 25.6 26.1 26.0 25.9 25.6 Oct 25.5 25.5 25.5 26.5 24.5 26.0 25.7 25.7 25.6 26.8 25.9 25.7 25.7 Nov 25.1 25.0 25.0 25.5 25.0 25.5 25.5 25.5 25.9 26.6 25.4 25.5 25.5 Dec 24.5 25.4 24.5 25.5 25.2 25.0 25.2 25.2 24.6 26.3 25.6 25.2 25.2 Appendix 3. Monthly rainfall of 1999 in Cicatih watershed Rainfall Stations Month Cicurug Sekarwangi Sinagar Cibunar Cipendeuy Cipetir Cikembang Pakuwon Selabintana Jan 478 441 482 108 514 507 453 368 304 Feb 397 358 426 180 322 361 317 406 272 Mar 233 244 253 263 233 402 147 250 481 Apr 293 255 371 31 343 247 275 201 392 May 215 223 138 193 366 267 281 131 256 Jun 150 132 160 15 164 139 131 196 157 Jul 91 56 83 31 30 60 40 93 130 Aug 71 83 65 40 55 131 77 127 153 Sep 91 80 117 20 20 131 24 104 205 Okt 278 278 285 244 198 303 176 562 287 Nov 187 245 221 325 335 271 271 229 538 Des 187 237 232 325 296 272 223 262 449 Appendix 4. Area rainfall of Cicatih watershed estimated using Thiesen Polygon Appendix 5. Digital Elevation Model DEM m Appendix 6. Map of 34 disturbed soil sampling points in Cicatih watershed Appendix 7. Map of water holding capacity WHC in Cicatih watershed Appendix 8. Calculation of monthly spatial runoff using PC Raster binding Input Map altitude=topomodi.map; area=boundary.map; thiesen=thiesen.map; lu=lu.map; initsoilwater=initsw.map; maxSWC=whc.map; subwatershed=Subwatershed.map; lust=nomlust.map; ldd0=ldd.map; Timeseries Data tmpkw = pkw.tss; precip=NewRain.tss; volrain=volrain.tss; volrunoff=volRo.tss; Output Tcct= Tcit; Tavetss=Tcit.tss; Tave=Tave; raintotal=total; raintotaltss=rainttl.tss; raintotalcct=totalcit; raintotalareatss=rainttlarea.tss; raintotalsub=totalsub; raintotalsubtss=rainttlsub.tss; volrainttltss=volrainttl.tss; rainnet=net; rainnettss=rainnnet.tss; rainnetcct=netcit; rainnetccttss=rainnetcct.tss; rainnetsub=netsub; rainnetsubtss=rainnetsub.tss; rainnetthis=netthies; PET=PET; PETsub=PETsub; PETsubtss=PETsub.tss; PETcct=PETcit; PETccttss=PETcit.tss; PETthis=PETthies; PETthistss=PETthies.tss; itss=i.tss; Pef=Pef; Pefccttss=Pefcit.tss; AET=AET; AETcct=AETcit; AETccttss=AETcit.tss; AETsub=AETSub; AETsubtss=AETsub.tss; AETthis=AETthies; AETthistss=AETthies.tss; SWC=SWC; SWCtss=SWC.tss; SWCcct=SWCcit; SWCccttss=SWCcit.tss; SWCsubtss=SWCsub.tss; SWClcst=SWClust; SWClcsttss=SWClust.tss; SMS=SMS; SMScct=SMScit; SMSccttss=SMScit.tss; SMSsub=SMSsub; SMSsubtss=SMSsub.tss; SMSlcst=SMSlust; SMSlcsttss=SMSlust.tss; SMD=SMD; SMDcct=SMDcit; SMDccttss=SMDcit.tss; SMDsub=SMDsub; SMDsubtss=SMDsub.tss; SMDlcst=SMDlust; SMDlcsttss=SMDlust.tss; Ro=runoff; Rocct=Rocit; Roccttss=Rocit.tss; Rolcst=Rolust; Rolcsttss=Rolust.tss; Rosub=Rosub; Rosubtss=Rosub.tss; volRo=volRo; volRotss=volRo.tss; acc=acc; accoutlettss=accoutlet.tss; Volacc=Volacc; Tabel Data portion=inter.tbl; areamap cicatih.map; timer 1 12 1; initial I=129; report koefportion=lookupscalarportion, lu; SWC=initsoilwater; WHC=maxSWC; dynamic Temperature report Tpkw=timeinputscalartmpkw,area; report Tcct=Tpkw+2.745-0.0061 altitude; report Tave=areaaverageTcct,area; report Tavetss=timeoutputthiesen,Tave; report tratabulan=timeoutputarea,Tave; Potential EvapotranspirationPET i = Tave5 1.516; report itss=timeoutputarea,i; I = sum of i a = 0.49 + 0.0179I - 0.0000771I2 + 0.000000675I3; report PET=1610TcctIa; report PETcct=areaaveragePET,area; report PETccttss=timeoutputarea,PET; report PETsub=areaaveragePET,subwatershed; report PETsubtss=timeoutputsubwatershed,PET; report PETthis=areaaveragePET,thiesen; Total Rainfall report raintotal=timeinputscalarprecip, thiesen; report raintotaltss=timeoutputthiesen,raintotal; report raintotalcct=areaaverageraintotal,area; report raintotalccttss=timeoutputarea,raintotal; report raintotalsub=areaaverageraintotal,subwatershed; report rainbrutsubtss=timeoutputsubwatershed,raintotal; report volrainttltss=maptotalraintotalcellarea262820000; Nett Rainfall report rainnet= raintotal koefportion; report rainettss=timeoutputarea,rainnet; report rainnetcct=areaaveragerainnet,area; report rainnetccttss=timeoutputarea,rainnet; report rainnetsub=areaaveragerainnet,subwatershed; report rainnetsubtss=timeoutputsubwatershed,rainnet; Effective RainfallPef report Pef= maxrainnetcct - PETcct,0; report Pefccttss=timeoutputarea,Pef; Soil Water ContentSWC report SWC=maxifPef gt 0 then ifSWC ge WHC then WHC+Pef else SWC+Pef else SWCexprainnetcct-PETcctWHC,0; report SWCcct=areaaverageSWC,area; report SWCccttss=timeoutputarea,SWC; report SWCsubtss=timeoutputsubwatershed,SWC; report SWClcst=areaaverageSWC,lust; report SWClcsttss=timeoutputlust,SWC; Actual EvapotranspirationAET report AET=ifSWC ge WHC then PET else PETSWCWHC; report AETcct=areaaverageAET,area; report AETccttss=timeoutputarea,AET; report AETsub=areaaverageAET,subwatershed; report AETsubtss=timeoutputsubwatershed,AET; Soil Moisture SurplusSMS report SMS= ifPef gt 0 then SWCcct-WHC else 0; report SMScct=areaaverageSMS,area; report SMSccttss=timeoutputarea,SMS; report SMSsub=areaaverageSMS,subwatershed; report SMSsubtss=timeoutputsubwatershed,SMS; report SMSlcst=areaaverageSMS,lust; report SMSlcsttss=timeoutputlust,SMS; Soil Moisture Defisit SMD report SMD=ifSMS gt 0 then 0 else PET-AET; report SMDcct=areaaverageSMD,area; report SMDccttss=timeoutputarea,SMD; report SMDsub=areaaverageSMD,subwatershed; report SMDsubtss=timeoutputsubwatershed,SMD; report SMDlcst=areaaverageSMD,lust; report SMDlcsttss=timeoutputlust,SMD; Runoff Ro report Ro=SWCexp0.3SWCWHC-exp- 0.3SWCWHCexp0.3SWCWHC+exp-0.3SWCWHC; report Rocct=areaaverageRo,area; report Roccttss=timeoutputarea,Ro; report Rosub=areaaverageRo,subwatershed; report Rosubtss=timeoutputsubwatershed,Ro; report Rolcst=areaaverageRo,lust; report Rolcsttss=timeoutputlust,Ro; report volRotss=maptotalRocellarea262820000; report volRo=timeinputscalarvolrunoff,area; Runoff accumulation report acc= accufluxldd0,Ro; accoutlet=mapmaximumacc; report accoutlettss=timeoutputarea,accoutlet; ii CALIBRATION OF MONTHLY SPATIAL RUNOFF FROM THE ROOT ZONE USING WATER BALANCE METHOD A Case Study in Cicatih Watershed, Sukabumi, West Java TEUKU ACHMAD IQBAL DEPARTMENT OF GEOPHYSICS AND METEOROLOGY FACULTY OF MATHEMATICS AND NATURAL SCIENCES BOGOR AGRICULTURAL UNIVERSITY 2006 iii ABSTRACT TEUKU ACHMAD IQBAL . Calibration of Monthly Spatial Runoff from the Root Zone Using Water Balance Method A Case Study in Cicatih Watershed, Sukabumi, West Java. Under the direction of DANIEL MURDIYARSO. This study calibrated the monthly spatial runoff from the root zone using simple water balance in Cicatih watershed, Sukabumi, West Java. Soil layer of 10-30 cm was taken to represent the root zone. The method of monthly runoff by Xiong and Guo 1999 was applied. Geographic information system GIS was used to estimate spatial and monthly runoff distributions. The result was satisfactory. The value of R 2 for Cicatih watershed was 66.15 and the relative error RE was 1.4 . It was capable of describing the monthly spatial runoff and had produced quite good estimation. Spatially distributed runoff clearly indicated the influence of rainfall, land cover types, and water holding capacity WHC. However, monthly runoff was only affected by the rainfall. The runoff contribution from the garden areas was the highest. The lowest contiribution of runoff was found in the grass areas. Monthly runoff from the forest areas was the highest over the year. It was found that runoff increased as the significant increased of rainfall. iv CALIBRATION OF MONTHLY SPATIAL RUNOFF FROM THE ROOT ZONE USING WATER BALANCE METHOD A Case Study in Cicatih Watershed, Sukabumi, West Java TEUKU ACHMAD IQBAL G 24101023 Research Report To fulfill the requirement for a Bachelor Degree in Science At the Department of Geophysics and Meteorology Faculty of Mathematics and Natural Sciences DEPARTMENT OF GEOPHYSICS AND METEOROLOGY FACULTY OF MATHEMATICS AND NATURAL SCIENCES BOGOR AGRICULTURAL UNIVERSITY 2006 v Title : CALIBRATION OF MONTHLY SPATIAL RUNOFF FROM THE ROOT ZONE USING WATER BALANCE METHOD A Case Study in Cicatih Watershed, Sukabumi, West Java Name : Teuku Achmad Iqbal Nrp : G 24101023 Approved by: Supervisor Prof. Dr. Daniel Murdiyarso NIP. 130804892 Dean of Faculty of Mathematics and Natural Sciences Bogor Agricultural University Dr. Ir. Yonny Koesmaryono, M.Si NIP. 131473999 Graduation date: vi BIOGRAPHY Teuku Achmad Iqbal was born in Jakarta at August 30, 1983 with parents name Teuku Syarif and Kemala Sari. He has two brothers. After graduation from the SMA 109 Jakarta in 2001, he was enrolled IPB through the USMI process. He joined the Department of Geophysics and Meteorology, Faculty of Mathematics and Natural Sciences in 20022003. He was a member of a student association interested in Agricultural Meteorology, HIMAGRETO. Iqbal was the assistant of Hydrometeorology Practical Class in 20052006. 1

I. INTRODUCTION