Joong Hi Ryu, Euihong Kim and Chang Hahk Hahm
A geographic information system (GIS) was a useful tool in the assessment of water quality by checking water pollutant loadings and building environmental information display and query system development.
This water quality management & environmental information display and query system was developed to provide all the informations that effect models to estimate pollutant's loadings and to select proper strategy of pollution control. Spatial database for geographic features and environmental informations was collected and created. Environmental informations also include attribute data for both non-point source and point source. ArcInfo was used for data input, management, display and manipulation. Powerful macro language, Arc Macro Language(AML) was used for developing user interface. During these procedures, special functions for quantify the characteristics of drainage system such as 3-D draping, automatic basin tracing, rainfall-path finding was rebuilt for easy interface. The user interface for Environmental Information Display and Query System was also programmed by using AML with boolean operation functionality. Every possible aspect for causing water pollution was pre-designed as menu style for easy use.
Most of the case, it was investigated that main reasons of water quality degradation of the country-wide waterway are point and non-point pollution from urban/agricultural areas. In order to reduce pollutant effects to water quality, we must have to set up the best control strategy and it should be stressed on the importance of initial assessment of point and non-point source problems. For this assessment, a water quality model to estimate pollutant loadings and input data to run this model will be required. The input data should be geographic features such as contour, road, stream, administrative boundary, ground control point and coordinates. It also includes environmental informations such as soil classification, land cover, forestry & vegetation and geomorphology. It should be very important for water quality management to maintain high accuracy of input data and these data should be linked with model by spatial-relations. Due to the lack of digital data source for geographic features, digitizing and raster-to- vector conversion technology after scanning were used.
This study was focused on producing environmental information by digital format and standardization of point, non-point source environmental information with coding scheme and building display & query system by using graphical user interface for easy use. GIS the state-of-the-art technology was adopted both systems itself and database management. All informations regarding topographic features and spatial information which composed of point, line, polygon was digitalized and related attribute data for non-point source pollutant were stored in the database management as tabular informations.
The main objectives of this study were user need assessment, database design and developing customized user interface for Input/Output program.
Other objectives of this study were collection of environmental attribute data through government organization and its input, make relation with graphic data. Construction of pilot database design for environmental attributes was also one of the objectives.
In overall, all the input data to estimate pollutant loadings such as administrative boundaries, DEM, soil maps, land-use, and industrial pollution data were collected on the basis of sub-basins. Other input items related to mitigation strategy (e.g. the siting of wastewater treatment facility) such as the statistics of live stocks, population, sewage water treatment system, etc. was collected for individual villages.
During data collection, individual collection units have unique codes to make standardized format. Each village has a 10-digit unique code: first two digits designate province, next three digits for city in a province, another two digit for towns in a city, and last three for villages in a town. Each sub-basin has 7-digit unique code; first digit designates major rivers, next digit for major streams in a river, another two digit for major tributaries in a stream and the last three digits for sub- basins in a tributary.
In administrative boundary layer, digitized from 1:50,000 topo maps, different level of administrative boundaries was included such as province, city, town, and village. For more discrete approach of estimating pollutant loadings and identification of the critical areas, a sub-basin layer digitized from 1:50,000 topo maps was made. A DEM layer of 100x100 meter spatial resolution was used. 20 meter interval contour line also digitized and used for creating 3-D features by using Triangulated Irregular Network (TIN).
Landuse coverages made from 1:25,000 topo maps has five categories; agricultural, residential, forest, open space, and miscellaneous. Soil was digitized using 1:50,000 soil maps and classified into eight classes. The location of water quality monitoring stations and major industry point sources were digitized from 1:50,000 topo maps for searching accumulated flows of point sources of major toxic wastes. In addition, a road network layer and hydrography layer were also made from 1:50,000 topo maps.
Table-1: Example of graphic data dictionary
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System Water Quality Management Data type Graphic
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Table_Name Soil.PAT
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Related Soil Attribute
Graphic
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COLUMN ITEM INPUT OUTPUT TYPE NO.Of Remarks
NAME WIDTH WIDTH Dec.
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1 AREA 8 18 F 3 Area
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9 PERIMETER 8 18 F 3 Polygon length
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17 Soil # 4 5 B Internal ID
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21 Soil-ID 4 5 B User ID
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25 S 3 3 I Soil
classification
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Attribute data that related with water quality such as night soil, domestic animals, landuse, industrial facilities, environmental facilities, water facilities (industrial, agricultural, living, intermittent), and stream details were also collected and designed / registered as following format (Table-2: Distribution of industrial facilities in details).
Table-2: Distribution of industrial facilities in details.
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ITEM NAME INPUT OUTPUT TYPE No. of Remarks
WIDTH WIDTH Dec.
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NAME-PLT 30 30 C Name of industrial facilities
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AORS-PLT 30 30 C Address
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MATI-PLT 30 20 C Material
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MPRO-PLT 20 20 C Production
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WAST-QUA 4 12 F 3 Waste water discharge
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DISCHARG 10 10 C Discharge rate
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LABOR-NU 4 4 I No. of Labor
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DISPOSAL 8 8 C Disposal facility
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COM-DISP 8 8 C
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Linkage was considered among each code to corresponding names of data collection unit in order to create, update, and delete text data for individual collection units. This also enables to query and statistical calculation for individual query unit according to user's need.
Standardized format was made for graphic and attribute data for the wider usage of the database. Also, unique codes were assigned to individual data collection units to enable easy data manipulation. During this study, major difficulties were in the data acquisition due to the absence of digital data in South Korea. Also text data for environmental information was not standardized and not managed well.
This study will be extended to nation-wide with further study regarding enhancing DBMS, data format conversion, and user interface for running models.
Kye Hyun Kim. Building an EIS for water Quality Management. Special Interest Group on Database, Korea,1995.
Chang Hahk Hahm and Sang Jin Ahn, An Extraction of Geometric Characteristics Parameters of Watershed by Using Geographic Information System, Journal of Korea Water Resources Association, vol.28 No.2, 1995.
Myung Jin Kim et al. Studies on Environmental Systems (I), (II) National Institute of Environmental Research, Korea,1991~1992
Kye Hyun Kim
Senior Researcher. Ph.D., Division of Global Environment Information
Systems Engineering Research Institute
P.O. Box 1) Yusung, Taejon,
Korea
Tel) 82-42-869-1572
Fax) 82-42-869-1599
Chang Hak. Hahm
Assistant Professor, Dept. of Aerial Survey
Inha Technical Junior College
Incheon, Korea
Tel) 82-32-870-2240
Fax) 82-32-868-3408