Water and Soil Management for Water Conservation in a Watershed - Water and Agriculture: Sustainability, Markets and Policies - page 298

with a high resolution image, a topographic map, a river map and an administration
district map. DB construction for non-point pollutants from land use and point pollutants
from living, livestock, industry, etc., was completed and then the estimation of pollution
loads was made with works for inquiry, revision, search and print function still remained.

Figure 6. Process and concept for pollution load assessment

Map DB Map DB Attribution DB Attribution DB

Geographical map
River map
Standard basin map
Treatment instrument
Administrative district

Geographical map
River map
Standard basin map
Treatment instrument
Administrative district

Pollutant source
Population & livestock
Land use
Treatment instrument
Water, soil, air quality

Pollutant source
Population & livestock
Land use
Treatment instrument
Water, soil, air quality

Print Function Print Function

Print Function Print Function

Map Inquiry Map Inquiry

Map Inquiry Map Inquiry

Transformation for EXCEL
Screen Layout Print
Attribution Information Print

Transformation for EXCEL
Screen Layout Print
Attribution Information Print

Topographical Map, River Map
Administrative District Map
Basic Instrument for Environment

Topographical Map, River Map
Administrative District Map
Basic Instrument for Environment

WQ Inquiry, Revision, Search WQ Inquiry, Revision, Search Pollution Inquiry, Revision, Search Pollution Inquiry, Revision, Search Estimation of Pollution load Estimation of Pollution load

WQ Inquiry, Revision, Search WQ Inquiry, Revision, Search Pollution Inquiry, Revision, Search Pollution Inquiry, Revision, Search Estimation of Pollution load Estimation of Pollution load

Application of Unit-Loads
Occurrence, Discharge,
Runoff Load

Application of Unit-Loads
Occurrence, Discharge,
Runoff Load

Data by
WQ(water quality) measurement

Data by
WQ(water quality) measurement

Population, Livestock, Industry
Site Discharging of Waste Water

Population, Livestock, Industry
Site Discharging of Waste Water

3. Crop land unit mapping by classification of land use
In this pollution load assessment system, we could not classify each field into
different types of land use because of the limit of programme size and image resolution.
But when one watershed has a pollution problem, different management practices should
be applied to each field for improving water quality in the watershed. Therefore, we tried
to classify land use through on-screen digitisation using high resolution aerial images, a
DEM (Digital Elevation Model) and a super-detailed soil map (1:5,000). Figure 7 shows
the result. Here, each field boundary was delineated on the basis of farmland unit. This
classification could be very helpful for a further study on soil erosion in each field. In
research on soil erosion in Korea, having small farm fields, very complex topography and
steep slope farmland at high altitude, it is not easy to get good results without
classification of each field. This will be a first step for the application of site-specific
BMP for the protection of the environment from non-point source pollution.