iii. result and discussion - geosmart asiachange in cimanuk watershed. 3. assessing theimpact of...

Firman Rismara

Master of Science in Information Technology for Natural Resources Management

Bogor Agricultural University



I. INTRODUCTION1. Background2. Research Objective3. Scope of Research

II. METHODOLOGY1. Research Area2. Research Procedure

a. Land Use Change Model (M-CA)- Data Preparation- Model Validation- Land Use Scenario

b. Hydrologic Model (HEC-HMS)- Data Preparation- Hydrologic Model Development- Hydrologic Model Calibration

III. RESULT AND DISCUSSION1. Land Use Change Model (M-CA)

a. Land Use Patternb. Driving Factorc. Model Validationd. Forecasting Land Use Scenario

2. Hydrologic Model (SWAT)a. Model Calibrationb. Impact of Land Use Change on

Water Availability

IV. CONCLUSION



Upper Stream Area

Lower Stream Area

•Build up area bigger than cropland/forest area;•Run Off discharge bigger than infiltration/percolation;•Soil type;



The population growth increase the demand of settlement andagricultural area;

Human activities in the upstream areas change the hydrologic condition;

Government Regulation Public Work Ministry and The Ministry of Forestry Republic of Indoneisa,

No. 19/1984, No.059/Kpts-II/1984, No.124/Kpts/1984

Critical Watershed Cimanuk Watershed



Land Use Change VS Hydrology

1 12

3 4

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The Objectives of this research are :1. Forecast the land use change for the next 20 years in the upper

stream of Cimanuk Watershed using Markov Chain-Cellular Automata (M-CA) Model.

2. Assess the impact of land use change prediction on water availability using hydrology model (SWAT).

Problem StatementResearch question related to the objectives are:1. What are the major trends of future land use change?• How has the land use in the research area changed during the

period of 1991 - 2002 and 2002 - 2010?• What are the trends of land use change in the research area

during 1991 - 2010?2. How are the impacts of land use change to water availability in the future?

Scope, limitation and assumption of this research are:

1. Research area as a boundary of hydrology system in this research is theupper stream of Cimanuk Watershed.

2. This research is intended to integrate Remote Sensing (RS) andGeographical Information System (GIS) for forecasting land usechange in Cimanuk Watershed.

3. Assessing the impact of land use change to water availability at theresearch area by employing hydrology model.

4. Based on the limitation of the M-CA Model, land use type only dividedinto 4 (four) types, i.e.: grassland, agriculture, settlement and forest.

5. In this research, hydrology model is only employed to explore theeffect of land use change to water yield, by comparing hydrograph foreach land use. Thus, modeling result will be calibrated with the fieldmeasurement data.





1. Research Area

2. Research Procedure :

a. Land Use Change Model (M-CA)

• Data Preparation

• Model Validation

• Land Use Forecasting Scenario

b. Hydrologic Model (SWAT)

• Data Preparation

• Hydrologic Model Development

• Hydrologic Model Calibration



The Upper Stream of Cimanuk Watershed

Administrative :Garut Regency in West Java Province- Indonesia

Geographic position :7o S – 7o 30’ S and 107o 30” E – 108o 15’ E.



Land Use Change VS Hydrology

MODEL

Land Use Model Hydrologic Model

M-CA SWAT



An important stage in the development of any predictive change model is validation.Typically, one gauge means the understanding of the process and the power of themodel by using it to predict some periods of time when the land use conditions areknown. This is then used as a test for validation.

Kappa is essentially a statement of proportional accuracy. Kappa is computed as:



Land Use Change Analysis During Period 1991 - 2002



Accuracy Assessment

Base on the validation process ,the result of validation using

Kappa Index is 86% and its

categorized as fit.

Forecasting Land Use Base on Scenario

1. Scenario 1 (base line scenario)Assumsion :• Land use change in future is the continuity of land use change in the

past ;• The demand of land use in the future (until the year 2030) is the

continuity of the demand of land use change 2002-2010;• There are no spatial policies applied, all of areas inside the study area

are possible to change to another land use.

Forecasting Land Use Base on Scenario 1

According to the change detection from the land use classification in year1991, simulated year 2010, 2020 and 2030, it can be seen that the settlement,forest and grassland area are increasing, whereas the agriculture tent todecrease.

Forecasting Land Use Base on Scenario

1. Scenario 2 (Spatial Policy Applied)Assumsion :• The demand of the land use is still the same with baseline;

• Spatial policies is apply where forest area based on forest

designation map from BAPPEDA West Java Province is not allowedto change to other land use.



Forecasting Land Use Base on Scenario 2

According to the change detection from the land use classification in year1991, simulated year 2010, 2020 and 2030, it can be seen that the settlement,forest and grassland area are increasing, whereas the agriculture tent todecrease.

WaterShed Delineation

Climatology Condition

Land Use and Soil Characteristic

Model Calibration

The model calibration done by adjusting the initial abstraction, curve number and imperviousvalues, until the result match with the data measurement. The process was completed manuallyby repeatedly adjusting the parameters, computing, and inspecting the goodness of fit betweenthe computed and observed hydrographs.

During calibration process by using half-year daily data (feb 1st, 2010 – July 31st, 2010), theaccuracy only achieved 0.523 of R-square.Performance of the model was objectively gave a good efficiency value (NSE) of 0.67 and 42.9%of relative volume errors (RVe).Using these validation tests it can be stated that the model is satisfactory accepted.



Impact of Land Use Changes Base on Scenarios to Water Availability

Two hydrographs were simulated by using the same parameters in which was used duringmodel calibration and validation.



It was found that land use changes in the area were mainly dominated by expansionof settlement area with the annual rate of change 1.17 % during 1991-2002, followed byforest (0.45 %) and grassland (0.46 %) in the same period. Agriculture is decrease inperiod 1991-2002 with annual rate of change -0.57 %. The trend of land use change in1991-2002 showed that the area faces the expansion of settlement, forest andgrassland area and the decrease of agriculture

Based on the findings, it can be concluded that settlement area were significantlyincrease during the period 1991-2002 and causing the pressures in the research area.The simulated hydrograph obtain the peak flow and water yield information for twodifferent land use scenarios. The values of each scenario peak flow are 81.3 m3/s and81.10 m3/s for scenario 1 and scenario 2, scenario. While the value of water yield are279,893,000 m3 and 280,878,000 m3 for scenario 1 and scenario 2.



THANK YOU



iii. result and discussion - geosmart asiachange in cimanuk watershed. 3. assessing theimpact of...

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