Development of Web-based Geographic Information System for Water Quality Monitoring of Watershed in Malang

— Human activity and climate change significantly impact water quality, especially in Malang's watershed. This research aims to develop a web-based Geographic Information System (Web- GIS) for water quality monitoring in that watershed. The water quality data had been collected from Enviromental Office of Malang District and Malang City. Water quality in this application was determined using the STORET method, comparing water quality data to water quality standards according to Government regulation so that the water quality status at each monitoring point will be known. The total 57 monitoring points are visualized spatially in this application based on the sampling location plotted by Global Positioning System (GPS). The longitude and latitude coordinates of the monitoring location had been converted in GeoJSON using Quantum GIS (QGIS) software. Google Map API key was used to display a sampling location map on the website. Web-GIS application was tested functionally using a black box, compatibility, and usability testing. Based on the testing results, it worked correctly on Chrome, Edge, Mozilla, and Opera browsers for PC/Laptops and also for browsers on Android smartphones version 4 and above. The application could be appropriately used and efficiently based on usability testing results. The design, architecture, and capabilities of this Internet GIS application were addressed, as well as the lessons learned and the prospects for Internet GIS development. remote sensing and GIS application to monitor water quality parameters as quality management. water


Development of Web-based Geographic Information
System for Water Quality Monitoring of Watershed in Malang

I. INTRODUCTION
Water is vital in the ecosystem since it is a fundamental requirement for all living organisms to survive [1]. The river has become one of the potential water resources used in Indonesia.
Generally, the most potent pollution sources come from an area's geological conditions, industry, agricultural activities, and wastewater treatment [2]. Domestic wastes caused by increasing human activity can pollute and affect river water quality along the watershed.
Water quality is determined by several factors, including physical and chemical properties [3] [4]. Temperature, electrical conductivity (DHL), suspended residue or total suspended solids (TSS), and total dissolved solids (TDS) are some of the physical characteristics [5]. The degree of acidity (pH), BOD, COD, DO, ammonia as N (NH3-N), nitrite as N, fatty oils, and metals (Cu, Fe, Cd, Mn, and Zn) are chemical parameters [4] [6]. It can be said that the water is polluted if the parameter value exceeds the government's quality standard.
Several studies below have shown that the river water quality in Malang City is decreasing.
Research results in the Brantas watershed, Dinoyo area, stated that BOD and COD levels exceed the water quality standards according to government regulations for class II. That water should be functionated for water recreation infrastructure/facilities, freshwater fish cultivation, livestock, crops irrigation, and or for other functions that require the same water quality as that standard [3].
The new study also supported it, claiming that the Brantas river could no longer bear the pollution load caused by high BOD levels, which have exceeded the quality standard [2]. The observation results of one segment in Metro River showed that COD levels exceeded the water quality standards required by the government. Meanwhile, the Metro River water flowing along the areas of Pisang Candi, Karang Besuki, Bandulan, and Sitirejo was moderately polluted water with an ASPT value of 4 -6.2 [7].
Other studies showed the same condition for river water quality in Malang Regency. Metro River flowing Pakis district was heavily polluted, even most of the river in the Upper Brantas watershed area of Malang was no longer suitable for agricultural use according to Government Regulation no. 82 of 2001 [8]. Another study result on Metro River in 2015 showed that the BOD and TSS parameters in the monitoring points of the downstream area exceeded the class II of water quality standard requirements [3]. Several years after that research, observations of rivers in Malang Regency were still being carried out. Analysis of the Metro river section of Pakisaji -Kepanjen District showed that the existing condition of the river exceeded the pollution load capacity of class II water quality standard [9].
The previous research below used GIS for monitoring water quality to support water quality assessment. Study [10]  The design, architecture, and capabilities of this Internet GIS application were addressed, as well as the lessons learned and the prospects for Internet GIS development. Research [11] used remote sensing and GIS application to monitor water quality parameters such as suspended matter, turbidity, phytoplankton, and dissolved organic matter to support water quality management.
Research [12] showed the implementation of GIS software to verify the river water quality model because of insufficient information in the research area. Research [13] shared an overview of the combination of GIS implementation and other technologies such as the Internet of Things [14], remote sensing, wireless sensor network, web, et cetera for water quality management and monitoring to maintain the water resources properly. GIS implementations were used to manage groundwater exploitation [15] [16]. The web-GIS model was also used to control some agricultural land in Papua [17].
Preventive action has been taken by Malang Environment Office (Dinas Lingkungan Hidup) by watershed water quality observation in specific measurement points every year. However, the data measurement was only stored and classified using a simple database in the office. Even the water quality condition of the watershed is not widely known yet by the public.
Controlling and managing the data measurement was done by providing a database that consistently records the periodic data. The database could be linked to the watershed measurement points, including the water quality parameters as indicators of the watershed condition. Therefore, it requires a web-based Geographic Information System (Web-GIS) to accommodate and support the system [10]. Decision Support System can be integrated with GIS based on user requirements [18], so that it can be easy to use for any user for their activity. Therefore, we developed a Web-GIS to monitor the watershed's water quality in Malang. We used the STORET method compared with the measurement results based on water quality standards [1] [19].

II. RESEARCH METHOD
Malang is located in East Java province Indonesia, dominantly consisting of the highlands. It   [20] The development of the Web-GIS application procedure refers to the modification of the System Development Life Cycle (SDLC) or waterfall model method [17]. According to [21][22], the information system development stages consist of 1) requirements/need analysis, 2) conceptual design, 3) database design, 4) application development, and 5) Web-GIS implementation and evaluation, as shown in Figure 2. Requirement analysis was used to identify the information system development, primarily to design the database, UI/UX, and software needs. Some information was collected by interviewing Malang Environment Office staff in Malang city and Malang District to discuss the required scope of the information system. The data used for the system development were watershed measurement results in Malang city and Malang Regency taken from 2018 to 2020. There were 57 measurement points.
The conceptual design was performed following needs and requirement analysis so that the application will be relevant to stakeholders as the system users [23]. Use case diagram and relation diagram were used to design the prototype of the system and the user interface. The Web-GIS application was developed using PHP programming language by Laravel framework, MySQL database, and QGIS software to convert mapping location/point into Geo-JSON format.
The information system was created using the system requirements already defined in the previous stage. The following steps were the system testing/implementation and evaluation to determine the suitability and verify the application as the final design. The system testing used a black box approach with several scenarios to determine the system functionality [24]. The usability was tested to find out whether the proposed system was suitable or not [25]. Office staff were as follows: a. Data recording of water quality measurement results was stored locally using Ms. Excel and Portable Document Format (PDF) format. The expected solution offered was to develop an information system with an integrated database.
b. Monitoring results were only well known by one division, so only one administrator could access the latest update of the data report. The expected solution was to create an information system with the latest data update that has opened access, so that the administrators could access the updated data.
c. There was no data history of water quality measurement/sampling results. The expected solution was to add sampling data history and to display the water quality parameters in time

Administrator
The admin's role is to update the water quality data from direct measurement on each watershed monitoring point. The admin role is divided into two areas, Malang City Administrator and Malang District Administrator. The feature of each administrator is: a. Managing water quality data of the city/district (CRUD data on water quality parameters of the city/district) b. Importing or exporting water quality data files into excel/Comma Separated Values (CSV) format.

Guest
The guest's role is to view news and water quality data directly at the home page without login into the application. MySQL database was used for this application development because the system required transparent relationships to reduce the possibility of table relations. Figure 4 shows a relationship diagram that describes the table's relationship. There were 13 tables in the database: user tables, kelurahan/urban village tables, sub-district tables, region tables to distinguish between city and district areas, location tables, biological parameter tables, physical and chemical parameters, river tables, password reset tables, and migration tables. The water quality parameter table was determined based on the analysis results of water quality parameters tested by the Environment Office of Malang City and Environment Office of Malang Regency.

III. RESULT AND DISCUSSION
This part discussed the results of a water quality monitoring application based on Web-GIS that has already been designed and developed. Figure 5 shows the dashboard page of that Web-GIS on desktop and mobile platforms. Every user can choose the map view integrated with the google map in any type, such as the default map, satellite, or terrain. On this page, we can also see the location point and list of rivers inside Malang city and Malang Regency watershed. The marker or color symbol of each point indicates the pH and BOD parameters of the river. The green color symbol indicates that they are still within the standard limit; the blue color symbol means that they are below that limit and the red one means that they are above that limit. The water quality parameters were determined based on the comparison between field measurement results and the water quality standard of Indonesian Government Regulation No. 82 year 2001, or STORET method [26], as shown in Table 1. The water quality standard implemented in this application is water class IV since the river function in Malang is mainly used for irrigation infrastructure and aquaculture.   The super admin carried out the river data input process through the dashboard, as shown in Longitude and latitude coordinate data were obtained from field sampling using Global Positioning System (GPS) according to sampling location by Environment Office. Data input of each water quality parameter and monitoring date for the city area and district area were carried out by their administrator, respectively, as shown in Figure 9. They were imported from the excel file format to simplify the data input process. City and district administrators could download their own water quality data for each monitoring point in excel/CSV file format. They were used for water quality reporting and time series data analysis.

Figure 9. A DMIN D ASHBOARD TO I NPUT W ATER Q UALITY P ARAMETER
The next step following the development of this information system prototype was system testing by users (which were Environment Office staff of Malang City and Malang District). The system testing was implemented using black box methods and involved numerous actions managed in the information system. The testing results are shown in Table 2. In addition, compatibility testing was also carried out by accessing the application through several browser types using both PC/notebook and smartphone. The browser types used for PC/laptops in this testing were Chrome, Edge, Mozilla Firefox, and Opera browser, whereas the browser types for smartphones were Chrome and Opera Mini browser. Based on compatibility testing results, all browsers were compatible to access the WebGIS applications. For the Android platform, the minimum application requirement was Android version 4 or above. Eight people who acted as guess, admin, and administrator tested the application's usability. Each user was Based on the usability testing result, all respondents said the application was user-friendly and easy to use. All features could work properly, and the system was ready to apply in Environment Office if the navigation pane was enlarged on the login form.

IV. CONCLUSION
A Web-GIS had been developed for water quality monitoring of watershed in Malang. The water quality parameters included both physical and chemical water quality parameters. They were based on monitoring data provided by the Malang City and Malang Regency Environment Office. The threshold of water quality parameters is based on water quality class IV following Environmental Regulations issued by the government. The Web-GIS application was developed using Laravel framework, MySQL database, QGIS, and Google Map API key to display google Maps on the website. It was tested using a black box, compatibility, and usability testing. Based on the testing results, it worked correctly on Chrome, Edge, Mozilla, and Opera browsers for PC/Laptops and also for browsers on Android smartphones version 4 and above. The application could be appropriately used and efficiently based on usability testing results.