| GISdevelopment.net ---> Technology ---> Geographic Information System |
Development of WEB-GIS program for River Basin Management in Indonesia
Ahmad Munir and Juni Astuti
Department of Agricultural Engineering Hasanuddin University-Jl.
Cokroaminoto University Makassar –Indonesia
E-mail:amunir@unhas.ac.id
Abstract
In Indonesia, the national government has to spend a large amount of money in order to conserve water quality. Since the regional autonomy is being involved, management of watershed becomes important issue. Because of many watersheds are occupied by more than one regional authority, therefore it is very hard to optimize watershed management. A computer program for river basin management have been developed in order to assist inter-region watershed management. The purpose of this paper is to describe the procedure and profile of an WEB-GIS program for the purpose of optimizing river basin management in term of minimizing erosion and sedimentation rate. The system was developed using Java, PHP and HTML and some supporter program such as MySQL, SVG Vew and ArcInfo were used to develop spatial database. Input data for the model consists of five spatial data: erosivity factor, erodibility, length-slope factor, land cover factor and conservation factor. All spatial data were being converted into geospatial format.
1. Introduction
During the recent decades in Indonesia, rapid exploitation of natural resources has increased pollution rate that has affects on ecosystems. This problem is reflected in increasing annual cost estimates on damage to water quality due to erosion rate through agricultural sources that range from $2.2 billion to $7 billion. Since the regional autonomy is being involved, management of watershed becomes important issue. Because of many watersheds are occupied by more than one regional authority, therefore it is very hard to get an ideal integrated management for optimizing water resources. The purpose of this paper is to describe the procedure, general feature and pplication of WEB-GIS program for River Basin Management in order to optimize water management in term of minimizing erosion and sedimentation rate. Web-GIS System Development The Web-GIS system for river basin managemen was developed using PHP and Html programming language. The system employs PHP, Java and HTML. It is mainly supported with Open Scalable Vector Graphics Map Server (Open SVGMap Server). This software is a free and an open source set of scripts that run on a web server, it was developed by Nedjo Roger, will dynamically generate vector map files from spatial data in a database. The scripts are in the PHP scripting language and are designed for use with a MySQL database. The input data to run the simulation consist of erosivity, erodibility, length slope factor, land cover factor and conservation factor. The data were generated in scaleable vector graphic (SVG) format, with attribute data in the form of Javascript arrays. The input and output file can be viewed through the Internet Explorer web browser with the SVG Viewer (a free browser plug-in from Adobe). Also included in the OpenSVGMapServer software distribution is a script that will export geospatial data and associated formatting information from the desktop GIS software application ArcView into a MySQL format suitable for use with OpenSVGMapServer. The software requires no special software on the web server beyond the free, open source, and broadly available MySQL database and PHP scripting. Development of Geospatial Data The Web-GIS program was applied at the Mamasa river basin, the main basin where the Garugu dam is located. The dam-site is located 250 km from the city of Makassar, on South Sulawesi, Indonesia (Fig. 1). The Mamasa River runs through the South and West Sulawesi Provinces that are occupied by four district (Kabupaten) authorities (Polewali-Mandar, Mamasa, Pinrang, and Toraja). Total area of the basin is about 108,072 ha (1,080 km2) which is positioned at 60 m to 2,873 m above sea level. The slopes of the basin vary between 15% - 45 %. Due to the soil structure of the region, the risk of landslides in the basin is high. Land use within the basin consists of dry-land and mixed agriculture (cocoa, coffee, and other tree crops), secondary forest, dry-land agriculture (maize, upland rice, and vegetables) and settlements. The run-off flows into the Mamasa River, which has a total length of 127 km. Geographically, the Mamasa River Basin is located on the coordinates of 119°13’ - 120°21’ East Longitude and 2°43’ - 3°46’ South Latitude. According to the government, the basin is located in 2 provincial regions, i.e. the West Sulawesi Province and the South Sulawesi Province. The West Sulawesi Province consists of the Mamasa District and the Polewali Mandar (Polman) District, whereas the regions of the South Sulawesi Province include a part of the Pinrang District and the Tana Toraja District. The river basin supplies all the water to the Garugu Dam for generating electricity in South Sulawesi Indonesia. Input data for the computer program are: geospasial data of erosivity, erodibility, and the slope-length, land cover and conservation factors.
Fig. 1. Location of Mamasa River Basin
The annual rainfall amounts in the Mamasa River Basin shows variability between the three stations. The averages of annual rainfall during the period 1988 – 2005 are 4644 mm, 2952 mm, and 2414 mm for the Sumarorong, the Minake and the Mamasa Stations, respectively. Each step of geospasial calculation was processed in the web server. Erosivity factors were established using the method proposed by Bols (1976). Isoerodent maps were developed from data for the Sumarorong, Minake and Mamasa meteorological stations. Erodibility factors were developed from land-based surveys that were conducted by the Institution for Rehabilitation and Conservation, South Sulawesi.
The soil in the basin consists of Ultisol and Alfisol-ordos (USDA, 1992). Udults and Udalfs-ordos are the common soil types found in the basin. The soil can be grouped into the following: Typic Tropudults (Podsolik), Typic Tropudalfs (Meditran) and Typic Hapludults (Brown Forest). Generally, the basin soil contains less clay and therefore has a low water holding capacity. Due to these properties, the soil is susceptible to erosion. Length and slope factors were developed using digital elevation models that were generated using IDRISI and SURFER programs. Steep slopes dominate the topography in the basin, and slopes between 25 and 40% occupy 40% of the drainage basin. The slope-length factor varies between 0.39 and 21.44.
Land cover data were generated from satellite imagery SPOT4. The data was interpreted using ERDAS software. It was found that the drainage basin is dominated by forest and arable land, with some parts of the drainage basin occupied by mixed agriculture (paddy fields and dryland agriculture). Historically, soil and water conservation projects have not been conducted in the basin, and it is estimated that no conservation practices are applied on more than 50% of the drainage basin.
Small areas of the drainage basin are managed using traditional conservation techniques (e.g. terracing). These small conservations regions are considered in the erosion simulation. In the web server, erosion rates is computed using Universal Soil Loss Equation (USLE) method (Wischmeier & Smith, 1978). Sedimentation due to surface erosion (SEP) is computed using SEP = E . SDR, where E is erosion rate (t ha-1 year-1) and SDR is sediment delivery ratio computed using the formula described by Roehl (1962) 20 . 0 36 - × = A SDR , where A is drainage area (km2). Sedimentation rate (m3 km-2 year-1) was computed using a density of the soil of 1200 kg m-3.
General Feature of the Web-GIS Program
The Web-GIS Program consists of tree main menus as shown in the following figures:
Fig 2. Main Menu of Web-GIS Program
The first menu is PETA DAS deals with running land use management based geospatial simulation. In this menu the user can optimize land use management by using Fuzzy Expert Facility that is provided in the program. By employing Fuzzy Expert, the program can generate the optimal land use for minimizing sedimentation rate in the dam that is located in the downstream of the basin. The second main menu is Upload Data DAS, deals with uploading geospatial data for the newriver basin. The geospatial data must be in form of MySql and Scalable Vector Graphic format. The third menu is Download, deals with downloading related frogram using in the Web-GIS program. An example of Management Interface Menu is presented in Fig. 3.
Fig. 1. An example of Open Management Interface Menu
Fig. 3. An example of viewing spatial data in the Web-GIS program
Result and Discussion
The Web-GIS program was applied at the mamasa River Basin Basin , South Sulawesi, Indonesia. The drainage basin is situated 250 km form the city of Makassar. Application of the system is proposed to optimize land use management in term of minimizing sedimentation rate in the Garugu Dam.
In the first step, the Web-GIS program was applied in order to know erosion rate at the Mamasa River Basin as well as to reduce sedimentation rate flow into Garugu Dam. The simulation was conducted using the land use data obtained from secondary data and SPOT4. Using the program, the generated erosion rate from the land use 2006 was obtained as shown in Table 1.
Tabel 1. Erosion and sedimentation rate generated from land use 2006
The generated erosion rate as shown in Table 1, is used for formulating several scenario of the land use in the river basin. The scenario is objected to reduce sedimentation rate flow into the Garugu Dam. The lowest erosion rate of the proposed land use is generated by using scenario 4. Base on the scenario 4, sedimentation rate in the Garugu Dam can be reduce from 2,210,231 m3/year become 1,071,586 m3/year. However, considering the economic feasibility of the total area that should be treated, this scenario cannot be proposed totally for future improvement.
Table 2. Erosion and Sedimentation Rate Generated from Future Land Use (With Project, Scenario 4)
From the output of the program, the following aspects should be take into consideration for the optimum riverbasin protection plan and program: 1)The Mamasa River Basin needs positive soil conservation measures in order to alleviate sediment production from fields on the slope, to maintain and improve agricultural production and resultantly to reduce the sediment inflow at the Garugu Dam; 2)The formulation of watershed protection plan shall be made taking into consideration regional socio-economical conditions and intention of farmers, etc. to realistically handle the soil erosion and sediment control from the watershed ;3) Both vegetative and civil engineering measures shall be applied for the critical areas of soil erosion and sediment production; 4) The implementation of the watershed protection project shall be realized with full support and understanding of farmers and shall be promoted with farmers’ participation. Based on these considerations, the following protection activities are envisaged: small gully plug, big gully plug, stream bank protection, and sloping grassing, terrace rehabilitation, community forest and nursery.
Furthermore, by applying the Web-GIS program, the land use development is used in order to evaluate land use declared by the local government. In the spatial plan (RTRW, 2006) of Mamasa Regency, the Mamasa River Basin is divided into several development zones.
Development of zone around Mamasa City can be proposed mainly for ecotourism and agrotourism (with fruit crops, vegetables and coffee plantation). In some areas of the drainage basin, zones are proposed for conservation forest, limited production forest, and agriculture (passion fruits, cashew nuts, coffee and vegetables). The sediment contribution of each scenario based on the spatial plan developed by the local government tend to be abandoned to reduce the sedimentation rate in the dam. Due to the economic orientation of the spatial plan developed by the local government, the sedimentation rate in the dam will increase. Conversely, the simulations based on scenario 4 in Table 2 were generated from a conservation point of view. It is therefore necessary to modify the existing spatial plan developed by the local government. A land capability approach may be suitable for the site specifics of the Mamasa River Basin. Sinukaban (1989) reported that inappropriate land use in the Mamasa River Basin causes tremendous sedimentation at the Garugu Dam. It can be prove that, by using the Web-GIS program, that is being run in internet performs a powerful instrument in developing variety of scenarios in order to reduce erosion and sedimentation in the Garugu Dam.
Conclusion
The Web-GIS program was developed as a tool in realizing open management for management of river basin in Indonesia. The system can be effectively involved in realizing integrated management for the watershed that is occupied by more than one regional authorities. The system can be used for decision support system base internet in term of decided: what land use type can be effectively used for minimizing erosion and sedimentation, which optional of soil conservation that can generated maximum income but however it has minimum effect of land degradation. In order to publish the system, a certain dissemination plan is required therefore the model can be recognized and applied by the related institutions. The Web-GIS program performs an effective instrument in reducing erosion and sedimentation rate in the Garugu Dam.
Acknowledgement. The Author wish to thank to the Ministry of Research and Technology of the Republic of Indonesia for supporting this research under the project of Riset Insentif in 2008.
Reference
In Indonesia, the national government has to spend a large amount of money in order to conserve water quality. Since the regional autonomy is being involved, management of watershed becomes important issue. Because of many watersheds are occupied by more than one regional authority, therefore it is very hard to optimize watershed management. A computer program for river basin management have been developed in order to assist inter-region watershed management. The purpose of this paper is to describe the procedure and profile of an WEB-GIS program for the purpose of optimizing river basin management in term of minimizing erosion and sedimentation rate. The system was developed using Java, PHP and HTML and some supporter program such as MySQL, SVG Vew and ArcInfo were used to develop spatial database. Input data for the model consists of five spatial data: erosivity factor, erodibility, length-slope factor, land cover factor and conservation factor. All spatial data were being converted into geospatial format.
1. Introduction
During the recent decades in Indonesia, rapid exploitation of natural resources has increased pollution rate that has affects on ecosystems. This problem is reflected in increasing annual cost estimates on damage to water quality due to erosion rate through agricultural sources that range from $2.2 billion to $7 billion. Since the regional autonomy is being involved, management of watershed becomes important issue. Because of many watersheds are occupied by more than one regional authority, therefore it is very hard to get an ideal integrated management for optimizing water resources. The purpose of this paper is to describe the procedure, general feature and pplication of WEB-GIS program for River Basin Management in order to optimize water management in term of minimizing erosion and sedimentation rate. Web-GIS System Development The Web-GIS system for river basin managemen was developed using PHP and Html programming language. The system employs PHP, Java and HTML. It is mainly supported with Open Scalable Vector Graphics Map Server (Open SVGMap Server). This software is a free and an open source set of scripts that run on a web server, it was developed by Nedjo Roger, will dynamically generate vector map files from spatial data in a database. The scripts are in the PHP scripting language and are designed for use with a MySQL database. The input data to run the simulation consist of erosivity, erodibility, length slope factor, land cover factor and conservation factor. The data were generated in scaleable vector graphic (SVG) format, with attribute data in the form of Javascript arrays. The input and output file can be viewed through the Internet Explorer web browser with the SVG Viewer (a free browser plug-in from Adobe). Also included in the OpenSVGMapServer software distribution is a script that will export geospatial data and associated formatting information from the desktop GIS software application ArcView into a MySQL format suitable for use with OpenSVGMapServer. The software requires no special software on the web server beyond the free, open source, and broadly available MySQL database and PHP scripting. Development of Geospatial Data The Web-GIS program was applied at the Mamasa river basin, the main basin where the Garugu dam is located. The dam-site is located 250 km from the city of Makassar, on South Sulawesi, Indonesia (Fig. 1). The Mamasa River runs through the South and West Sulawesi Provinces that are occupied by four district (Kabupaten) authorities (Polewali-Mandar, Mamasa, Pinrang, and Toraja). Total area of the basin is about 108,072 ha (1,080 km2) which is positioned at 60 m to 2,873 m above sea level. The slopes of the basin vary between 15% - 45 %. Due to the soil structure of the region, the risk of landslides in the basin is high. Land use within the basin consists of dry-land and mixed agriculture (cocoa, coffee, and other tree crops), secondary forest, dry-land agriculture (maize, upland rice, and vegetables) and settlements. The run-off flows into the Mamasa River, which has a total length of 127 km. Geographically, the Mamasa River Basin is located on the coordinates of 119°13’ - 120°21’ East Longitude and 2°43’ - 3°46’ South Latitude. According to the government, the basin is located in 2 provincial regions, i.e. the West Sulawesi Province and the South Sulawesi Province. The West Sulawesi Province consists of the Mamasa District and the Polewali Mandar (Polman) District, whereas the regions of the South Sulawesi Province include a part of the Pinrang District and the Tana Toraja District. The river basin supplies all the water to the Garugu Dam for generating electricity in South Sulawesi Indonesia. Input data for the computer program are: geospasial data of erosivity, erodibility, and the slope-length, land cover and conservation factors.
Fig. 1. Location of Mamasa River Basin
The annual rainfall amounts in the Mamasa River Basin shows variability between the three stations. The averages of annual rainfall during the period 1988 – 2005 are 4644 mm, 2952 mm, and 2414 mm for the Sumarorong, the Minake and the Mamasa Stations, respectively. Each step of geospasial calculation was processed in the web server. Erosivity factors were established using the method proposed by Bols (1976). Isoerodent maps were developed from data for the Sumarorong, Minake and Mamasa meteorological stations. Erodibility factors were developed from land-based surveys that were conducted by the Institution for Rehabilitation and Conservation, South Sulawesi.
The soil in the basin consists of Ultisol and Alfisol-ordos (USDA, 1992). Udults and Udalfs-ordos are the common soil types found in the basin. The soil can be grouped into the following: Typic Tropudults (Podsolik), Typic Tropudalfs (Meditran) and Typic Hapludults (Brown Forest). Generally, the basin soil contains less clay and therefore has a low water holding capacity. Due to these properties, the soil is susceptible to erosion. Length and slope factors were developed using digital elevation models that were generated using IDRISI and SURFER programs. Steep slopes dominate the topography in the basin, and slopes between 25 and 40% occupy 40% of the drainage basin. The slope-length factor varies between 0.39 and 21.44.
Land cover data were generated from satellite imagery SPOT4. The data was interpreted using ERDAS software. It was found that the drainage basin is dominated by forest and arable land, with some parts of the drainage basin occupied by mixed agriculture (paddy fields and dryland agriculture). Historically, soil and water conservation projects have not been conducted in the basin, and it is estimated that no conservation practices are applied on more than 50% of the drainage basin.
Small areas of the drainage basin are managed using traditional conservation techniques (e.g. terracing). These small conservations regions are considered in the erosion simulation. In the web server, erosion rates is computed using Universal Soil Loss Equation (USLE) method (Wischmeier & Smith, 1978). Sedimentation due to surface erosion (SEP) is computed using SEP = E . SDR, where E is erosion rate (t ha-1 year-1) and SDR is sediment delivery ratio computed using the formula described by Roehl (1962) 20 . 0 36 - × = A SDR , where A is drainage area (km2). Sedimentation rate (m3 km-2 year-1) was computed using a density of the soil of 1200 kg m-3.
General Feature of the Web-GIS Program
The Web-GIS Program consists of tree main menus as shown in the following figures:
Fig 2. Main Menu of Web-GIS Program
The first menu is PETA DAS deals with running land use management based geospatial simulation. In this menu the user can optimize land use management by using Fuzzy Expert Facility that is provided in the program. By employing Fuzzy Expert, the program can generate the optimal land use for minimizing sedimentation rate in the dam that is located in the downstream of the basin. The second main menu is Upload Data DAS, deals with uploading geospatial data for the newriver basin. The geospatial data must be in form of MySql and Scalable Vector Graphic format. The third menu is Download, deals with downloading related frogram using in the Web-GIS program. An example of Management Interface Menu is presented in Fig. 3.
Fig. 1. An example of Open Management Interface Menu
Fig. 3. An example of viewing spatial data in the Web-GIS program
Result and Discussion
The Web-GIS program was applied at the mamasa River Basin Basin , South Sulawesi, Indonesia. The drainage basin is situated 250 km form the city of Makassar. Application of the system is proposed to optimize land use management in term of minimizing sedimentation rate in the Garugu Dam.
In the first step, the Web-GIS program was applied in order to know erosion rate at the Mamasa River Basin as well as to reduce sedimentation rate flow into Garugu Dam. The simulation was conducted using the land use data obtained from secondary data and SPOT4. Using the program, the generated erosion rate from the land use 2006 was obtained as shown in Table 1.
Tabel 1. Erosion and sedimentation rate generated from land use 2006
The generated erosion rate as shown in Table 1, is used for formulating several scenario of the land use in the river basin. The scenario is objected to reduce sedimentation rate flow into the Garugu Dam. The lowest erosion rate of the proposed land use is generated by using scenario 4. Base on the scenario 4, sedimentation rate in the Garugu Dam can be reduce from 2,210,231 m3/year become 1,071,586 m3/year. However, considering the economic feasibility of the total area that should be treated, this scenario cannot be proposed totally for future improvement.
Table 2. Erosion and Sedimentation Rate Generated from Future Land Use (With Project, Scenario 4)
From the output of the program, the following aspects should be take into consideration for the optimum riverbasin protection plan and program: 1)The Mamasa River Basin needs positive soil conservation measures in order to alleviate sediment production from fields on the slope, to maintain and improve agricultural production and resultantly to reduce the sediment inflow at the Garugu Dam; 2)The formulation of watershed protection plan shall be made taking into consideration regional socio-economical conditions and intention of farmers, etc. to realistically handle the soil erosion and sediment control from the watershed ;3) Both vegetative and civil engineering measures shall be applied for the critical areas of soil erosion and sediment production; 4) The implementation of the watershed protection project shall be realized with full support and understanding of farmers and shall be promoted with farmers’ participation. Based on these considerations, the following protection activities are envisaged: small gully plug, big gully plug, stream bank protection, and sloping grassing, terrace rehabilitation, community forest and nursery.
Furthermore, by applying the Web-GIS program, the land use development is used in order to evaluate land use declared by the local government. In the spatial plan (RTRW, 2006) of Mamasa Regency, the Mamasa River Basin is divided into several development zones.
Development of zone around Mamasa City can be proposed mainly for ecotourism and agrotourism (with fruit crops, vegetables and coffee plantation). In some areas of the drainage basin, zones are proposed for conservation forest, limited production forest, and agriculture (passion fruits, cashew nuts, coffee and vegetables). The sediment contribution of each scenario based on the spatial plan developed by the local government tend to be abandoned to reduce the sedimentation rate in the dam. Due to the economic orientation of the spatial plan developed by the local government, the sedimentation rate in the dam will increase. Conversely, the simulations based on scenario 4 in Table 2 were generated from a conservation point of view. It is therefore necessary to modify the existing spatial plan developed by the local government. A land capability approach may be suitable for the site specifics of the Mamasa River Basin. Sinukaban (1989) reported that inappropriate land use in the Mamasa River Basin causes tremendous sedimentation at the Garugu Dam. It can be prove that, by using the Web-GIS program, that is being run in internet performs a powerful instrument in developing variety of scenarios in order to reduce erosion and sedimentation in the Garugu Dam.
Conclusion
The Web-GIS program was developed as a tool in realizing open management for management of river basin in Indonesia. The system can be effectively involved in realizing integrated management for the watershed that is occupied by more than one regional authorities. The system can be used for decision support system base internet in term of decided: what land use type can be effectively used for minimizing erosion and sedimentation, which optional of soil conservation that can generated maximum income but however it has minimum effect of land degradation. In order to publish the system, a certain dissemination plan is required therefore the model can be recognized and applied by the related institutions. The Web-GIS program performs an effective instrument in reducing erosion and sedimentation rate in the Garugu Dam.
Acknowledgement. The Author wish to thank to the Ministry of Research and Technology of the Republic of Indonesia for supporting this research under the project of Riset Insentif in 2008.
Reference
- Banasik, K. (1989) Estimation of effects of land use changes on storm event sediment yield from a small watershed. In: Sediment Transport Modeling (ed. by S. Y. Y. Wand) (Proc. Int. Symp.) ASCE, New York, US A.
- Bols, P. L. (1976) The iso-erodent map of Java and Madura. Belgian Technical Assistance Project ATA 105, Soil Research Institute, Bogor, Indonesia.
- CTI Engineering (1993) Study on River Mouth Close. Supervision of Construction for the Project of Lower Jeneberang River. Urgent Flood Control Works. Department of Public Works, Ujung Pandang, Indonesia.
- CTI Engineering (2001) Ground Survey and Soil Survey Works for Soil Conservation and Revegetation Works in The Bili-Bili Multipurpose Dam Project, Makassar. Department of Public Works, Ujung Pandang, Indonesia.
- Munir, A., Suripin & Abdullah, M. N. (2002) Model Peramalan Erosi Berbasis SIG. Laporan Penelitian Riset Unggulan Terpadu. Kantor Kementerian Riset dan Teknologi-LIPI. (A report on integrating research and erosion modelingbased GIS). Jakarta, Indonesia.
- Munir, A. & Suripin (1998) Application of GIS system-IDRISI for assessing soil erosion on Wonogiri catchment area. Bulletin Penelitian (Research Bulletin Hasanuddin University) UNHAS, no. 33 Vol. XIV, Makassar, Indonesia.
- Munir, A., Suripin, Abdullah, N. M. & Marutani, T. (2000) Application of Geographic Information System (GIS-IDRISI) for assessing land use risks on sediment yields. J. Fac. Agric. 44, 463–471. Lab. of Watershed Env. Sci. and Tech., Kyushu Univ., Fukuoka 812-8581, Japan.
- PPLH (2001) Study of Integrated Management on Jeneberang Watershed. Phase II (Final Report). CIDA-CEPI-UCEPPLH, Pusat Penelitian Lingkungan Hidup (Center for Environmental Studies), Makassar, Indonesia.
- Roehl, J. E. (1962) Sediment source areas, and delivery ratios influencing morphological factors. Int. Assoc. Hydro. Sci. Publ. 59, 202–213.
- RTRW (2002) Review Rencana Tata Ruang Wilayah, Kabupaten Mamasa (Spatial Plan Report). Proyek Pendayagunaan Penataan Ruang Nasional dan Daerah, Bagian Proyek Penataan Ruang Propinsi Sulawesi Selatan, Indonesia. Departemen Pekerjaan Umum (Department of Public Works), Republic of Indonesia.
- Sinukaban, N. (1989) Soil and Water Conservation in Transmigration Areas (Core Manual). Directorate of Settlement’s Environmental Uses, Directorate General for Settlement Preparation. Ministry of Transmigration, Indonesia.
- USDA (1992) Keys to Soil Taxonomy, fifth edition. United States Department of Agriculture, Natural Resources Conservation Service. Pocahontas Press, Blacksburg, Virginia, USA.
- Wischmeier, W. H. & Smith, D. D. (1978) Predicting Rainfall Erosion Losses—A Guide to Conservation Planning. Agricultural Handbook 537. USDA, Agricultural Research Service, Washington, DC, USA.
- Zubair, H., 2001. Pengendalian Sedimen di Waduk Bili-Bili dan Implikasinya pada Pengelolaan DAS Jeneberang di Kabupaten Gowa (sediment control on Bili-Bili Dam), Sulawesi Selatan, CIDA-CEPI-UCE and PPLH Universitas Hasanuddin, Makassar, Indonesia.