Home Articles Development of Web GIS for groundwater management

Development of Web GIS for groundwater management

Jumadi


Jumadi
Faculty of Geography, Muhammadiyah University of Surakarta, Indonesia
E-mail: [email protected]

Priyono
Faculty of Geography, Muhammadiyah University of Surakarta, Indonesia

Yuli Priyana
Faculty of Geography, Muhammadiyah University of Surakarta, Indonesia

Agus Anggoro Sigit
Faculty of Geography, Muhammadiyah University of Surakarta, Indonesia

Sigit Widiadi
Banyumas Regency Bureau of Energy and Mineral Resource, Indonesia

With the nature of Indonesia as a tropical country with abundant surface water, the intensity of groundwater use is supposed to be shrinkable. However, empiric situation has led to groundwater exploitation. This situation needs to be controlled as excessive exploitation leads to basin damage that can result in land subsidence and seawater intrusion (ESDM, 2009).

Consistent with Santosa & Adji (2007) and Sudarmadji (2006), data shows that freshwater demand in Banyumas Regency continuously rises along with advancement in regional development. Statistics reveal a 6.16 percent increase of tap water consumption in 2007 (11,383,923m3) as compared to the figures in 2004. As much as 8,631,101 m3 of 2007 regional water consumption is to satisfy domestic needs (Banyumas Statistics Bureau, 2007). On the other hand, the 2007 annual requirement of freshwater supply for domestic needs is estimated to be 76,447,020 m3. As a consequence, to meet this requirement, supply from water tap is insufficient. The use of groundwater through dug wells, pumped wells, or drilled wells then becomes inevitable.

As a preventing measure to unsustainable groundwater use, attentive groundwater management takes into account regional, physical and human-related factors. Physical factors refer to the environmental carrying capacity to groundwater supply while human-related factors refer to method, pattern and intensity of human activities that influence the preservation effort. In detail, physical factors include rainfall, geology, geomorphology, geohydrology, the presence of groundwater basin and land use. Human-related factors include the excessive groundwater use, human-induced environment degradation in recharge area, pollution and inappropriate groundwater sampling procedures.

As an attempt of providing strategic input to tactical decision-making within the groundwater management objective, the establishment of administering protocol through the provision of regional groundwater database with spatial orientation is involved. In accordance with this, the development of Spatial Decision Support System (SDSS), as said by Malczewski (1999) to be the advancement of Geographic Information System (GIS), is needed.

Research method
Malczewski (1999) mentions Spatial Decision Support System (SDSS) to be an interactive, computer-based system designed to support a user or a group of users in achieving higher effectiveness in decision-making process while solving a semi-structured spatial decision problem. Compared to Geographic Information System (GIS), which can be described as a piece of software that can perform generic spatial analysis and geo-processing methods towards sets of geographic data and requires an analyst or expert as operator, Spatial Decision Support System (SDSS) is a domain or an industry-specific software with no necessity of operator presence. As the name suggests, Spatial Decision Support System (SDSS) enables support for decision-making, but to do so, the presence of domain expert made of spatial analysis, geo-statistics, geo-processing or other tools from spatial information science is required. To start with, Spatial Decision Support System (SDSS) must be designed to address specific questions with geographic elements. Therefore, relevant up-to-date spatial data along with algorithms from spatial information science, domain-specific models to answer domain-specific questions, and a method of visualisation must be accessible . nomad-labs.com), Furthermore, Malczewski (1999) details Spatial Decision Support System (SDSS) in three major activities, namely: Database Management System (DBMS) and geographic database; a Model Based Management System (MBMS) and model based; and Dialogue Generation and Management System (DGMS).

Literature review
This stage is carried out to explore diversity of related data and information from books, journals, research and the Internet, serving as background for this study.

Peer observations and discussion
This phase aims at discussing data, information and procedures needed in the development of Spatial Decision Support System (SDSS). Personnel from multi-disciplinary background (geology, geography, information technology and management) take part in the discussion.

Geodatabase Management System (DBMS) development
The Geodatabase Development method adopts Artur & Zeiler (2004) procedure that consists of three main phases, i.e. conceptual, logical, and physical design.

Model Based Management System (MBMS) development
This phase develops procedures and methods to support decision-making in groundwater exploration management. Procedures and methods are developed from common practice of groundwater management in Banyumas Regency. The common practice is regarded as conceptual model. Spatial data is involved to establish an integrated system.

System development
System development procedures employ waterfall model as suggested in Demers (1997). The waterfall model is constructed from four main stages: 1) defining System Requirements; 2) proceeding System Development; 3) carrying out Test and Evaluation; and 4) implementation. Being called so as the model requires sequential process, meaning that one phase cannot be implemented before the completion of initial stage.

Result and discussion

Study area
The study area is Banyumas Regency, which lies within Central Java Province, Indonesia (see Figure 1) and measures 1,327.60km2 (132,759.56ha). The centre lies between mainland and mountains, through Serayu River valley that is used mainly for agricultural purpose. Most of the highland is allocated for settlements, while the mountainous area is for plantations and tropical forests. Banyumas Regency is an area with high potential of natural resources as it is situated within the vincinity of active volcano (Mt. Slamet) with its fertile vulcanic soils and vast forest. The weather is influenced by wet tropical climate. Local temperature ranges from 21.4°C to 30.9°C. Being situated between the slopes of mountains far away from coast, sea breeze effect is not apparent. With the low-lying southern coast, the wind seems to cross the mountain, headed to valley with 1001mbs averaged pressure (https://www.wikipedia.org).


Figure 1. Study Area

Result of geodatabase development
Database used in this application is spatial database originated from primary and secondary data source, with the inclusion of some non-spatial data. The primary source is field survey to locate the existing wells, industrial areas, and other groundwater users, while the secondary data source is project and research documentation, and digital map (see Table 1).


Table 1. Data and Sources Used for Geodatabase Development

Data is stored in a database system in a MySQL table. The GEOMETRY data type from MySQL Spatial is used to enable storing spatial data in point, line or polygon format. Spatial extension in MySQL allows storage of geographic objects that are usable in Geographic Information System (GIS) applications. Based on the specifications of the OGC, every MySQL Spatial object/layer is saved in separated table within the database, with one record in the table of each spatial feature (MicroImages, 2006).

Result of Model Based Management System (MBMS) development
This system uses several maps bearing physical factors information as input, being: map of geology; map of geohydrology; map of precipitation; map of geomorphology; map of wells location; map of groundwater conservation plan; map of groundwater basin; and map of potential groundwater source. This input data is stored within a RDBMS database aimed at serving as basis for implementing the managerial procedures in groundwater conservation. With inclusion of existing and potential wells location data, all before-mentioned data supports the decision-making whether or not consent for groundwater exploration at specific site will be issued.

The issue of consent follows some procedures. When applicants lodge their proposal, system will ask for the coordinates of parcel site where the well to be situated and the specific coordinates of the drilling plan (obtainable through the use of Global Positioning System apparatus). In practice, locating coordinates will be carried out by appointed officer acting as surveying person within the management body. Coordinates will then be used by system to perform spatial query referring to the intersection of MySQL Spatial analysis in order to extract environmental information (as so called ‘physical factors’ information: geology; geohydrology; precipitation; geomorphology; groundwater basin; and potential groundwater source) about the proposed well location. As assessment criteria, the proposed plan is to satisfy the conservation zoning plan, water quality requirement, groundwater potential criteria, and exploration ownership criteria. Conservation zoning is developed based on local policy; groundwater potential is analysed based on environmental condition and pumping test; and water quality is assessed through laboratory test. This dataset is to generate recommendation for consent (see Figure 2). If, based on suitability criteria having been applied, the proposal is permissible, the system user will perform technical analysis to make recommendation for issuing groundwater exploration consent. If, within the groundwater conservation plan, the proposed location does not comply with the zoning, system will refuse to issue consent.


Figure 2. Groundwater Exploration Recomendation Form

For approved applications, when drilling completed, system will request information in accordance with existing rock bedding at drilling site. This information will then be used to publish recommendation of well construction. The construction blueprint is automatically provided by system (see Figure 3). This recommendation is given with taking into consideration type of utilisation and environment-friendly discharge procedure alternative. Other considerations include pumping test to determine the amount of groundwater permissible to be explored and laboratory test to confirm water quality.


Figure 3. Well Profile Modeling

Once information in regard with an application is obtained, next procedure to be done by authorities is field check to verify information provided by system and to attain documentation for supporting the issue of Water Use Permit (SIPA). The Water Use Permit (SIPA) is to be issued for certain time period and renewable after expiry through resubmitted application. Through this procedure, continuous monitoring of groundwater use is enabled, and deterrent consequence can apply for groundwater users when non-complying use is proven. Information resulted from monitoring measure is then used as basis for decision-making in determining subsequent use of the groundwater source. Decisions are to satisfy the optimisation of groundwater use and conservation.

Dialog Generation (DGMS) development
The user interface adopts common desktop GIS application design in order to create user-friendly environment (see Figure 4). The main page includes a set of toolbar representing spatial and non spatial features, menus, navigation, and geographic analysis tools. These tools can be classified into 9 categories, being: 1) Header and Title; 2) Main Menu, 3) Sub Menu; 4) Map Navigation Tool; 5) control layer, legend, and data retrieval; 6) Layer Control; 7) Space Map; 8) inset map; and 9) panel pointer.


Figure 4. Application User Interface

Controlling of input and output data is built in such way that enables users to operate applications. Combo box optimization and utilisation of AJAX technology to display standard data fields provide users with an interactive display that enhances the possibility of reducing human error in input data process.

System implementation
System developed through this study is highly applicable in some stages of groundwater management practice and expected to nurture practical benefits such as: 1) providing information about site setting (both physical and human-related setting) of proposed groundwater use; 2) serving as a tool for rock layers data inventory; 3) simplifying the protocols needed for the issue of consent and recommendation in groundwater use; 4) serving as a tool for monitoring amount and quality of groundwater supply; 5) serving as a tool for controlling groundwater use; 6) simplifying administrative reporting task in groundwater management practice; 7) enabling spatial suitability model of well locations; 8) enabling rock bedding modelling; and 9) monitoring and controlling well development and distribution.

Conclusion
As performed through this study, MySQL database is employed to establish geodatabase compiling both spatial and non-spatial data. Visualised and managed with customised user interface and enabling spatial modelling practice using PHP and Java applet, system developed through this study supplies effective decision support system for groundwater use management.

Acknowledgements
We would like to say thanks to institution and person who involved on this study, ESDM Agency Banyumas, especially The chairman and Mr. Junaidi. Also special thanks for Bujed Pamungkas who gave peer review to the article.

Reference

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  • ESDM. 2009. Potensi Cekungan Air Tanah Indonesia. From
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