Realization of a Society in Harmony with the Environment

zResearch Trends and Results

Development of a Land-based
Pollution Load Model inNorthwest Pacific
MATSUMIYA Yosuke, Head, YOSHIDA Toshiaki, Senior Researcher, FUJIWARA Hiromichi, Researcher
Wastewater System Division, Water Quality Control Department

2. Development of a land-based pollution loadmodel
To clarify the future pollution load reduction
effectiveness of providing sewerage systems, ourDivision adopted a method of verifying theeffectiveness of pollution load reduction measures bydeveloping a land-based pollution load model andsetting future scenarios. In 2009, our Division started
by developing a land-based pollution load model forChina.
To develop the model, our Division referenced theframework of Comprehensive Basin-wide Planning ofSewerage Systems in Japan, and adopted a model
where pollution loads are calculated by totaling
pollution loads (COD, T-N, and T-P) discharged fromsources of each category such as residential andindustrial in each drainage basin block, then totaling
pollution loads from the upstream to the downstreamof rivers to obtain pollution loads reaching coasts. The
basic land unit for land-based pollution load
calculation is an administrative unit (prefecture or
Number of river basin
上流から下流までのblocks from upstream
流域ブロック分割数
to downstream
黄河流域
7 7
Yellow
River Basin
淮河流域
3 3
Huai River
Basin
Chang長江流域
Jiang River Basin
7 7
Major
主要流域
river basins）

Chang
Jiang River
長江流域
Basin

生活系
Residential
600
600

Paddies
水田

Factories
工場系
Fields
畑

Live
畜産系
stock
Urban
市街地

Others
その他

Urban
市街地

山林
Forests

Fields畑
Paddies
水田

500
500

Forests
山林

400
400

Others
その他
Livestock
畜産系
Factories

300300

工場系

200

200

Residential

100

生活系

100-0Bohai
Yellow
China Sea渤海Sea
黄海 Sea East東シナ海
Figure 2. Results of Approximate Calculation of Annual
Discharged Load (CODMn) in 2005
渤海黄海東シナ海city), and river basin block divisions for each water
quality monitoring points (where both water quality
and water quantity are measured) are set in majorrivers.
Figure 2 shows the results of applying the land-based
pollution load model to approximately calculate theannual discharged COD loads in each drainage basin
in 2005. The modeling included uncertain elements,
but it can clarify trends in the annual total discharged
loads and the percentages of total discharged pollution
loads of each category. More accurate results for thedischarged loads will be obtained in 2010.
3. Cooperation with Overseas Researchers
Our Division is working cooperatively withresearchers from China, Japan, Korea, and Russia toconfirm the appropriateness of the land-based
pollution load model and to promote concerted efforts
by the countries. Fruitful discussions have been
conducted at an international symposium at Kyoto
University in January 2009 and at an international
conference in Tokyo in February 2010.

Bohai
渤海SeaYellow
River Basin
黄河流域

Huai
River Basin淮河流域

700700

排出負荷量（万ｔ/年）

1. Introduction
In countries adjacent to Japan, recent rapid population
growth and industrial development have beenaccompanied by an increasingly serious river andocean water pollution problem. To propose water
quality environment conservation measures forNorthwest Pacific (Bohai Sea, Yellow Sea, East China
Sea, and Sea of Japan) by reducing land-based
pollution loads mainly through sewerage systems, ourDivision is conducting a research in collaboration withresearchers from the concerned countries (China,Japan, Korea, and Russia).

Dischargedload （万(10,000）
排出負荷量t/年t/year)

Research Trends & Results(Key words) marine environment, pollution load, simulation, sewerage system

YellowSea
黄海EastChina
Sea
東シナ海Figure 1. Major River Basin Blocks in China

4. Future Works
Based on past research results, our Division conducts
improvement of the land-based pollution load model,
setting of future scenarios and clarification of future
pollutant loads, prediction of the marine water quality
through marine simulations, and also the preparationof proposals for marine water quality environment
conservation for Northwest Pacific.
http://www.nilim.go.jp/lab/ebg/kinkai1.pdf.pdf
http://www.nilim.go.jp/lab/ebg/ (Wastewater System Div.)