Water quality improvement throughestablishing domestic wastewater governanceCase study: Lake Teganuma, Chiba, Japan
Yukako Inamura
WEPA Secretariat
Institute for Global Environmental Strategies (IGES)
April 22, 2022

Today’s outline
 Introduction and background Governance Historical review
 Key policies and measures Policy evaluation
 Message from the case2

The Lake Teganuma watershedLocated in Northwestern Chiba Prefecture (about 20 km from Tokyo)
Seven municipalities in the watershedMajor inflowing rivers: Ohori River, Otsu River, Kanayama-otoshi, Someiiriotoshi, and Kamenari River
Gunma

Tochigi

The lake andwatershed

Nagareyama

Abiko

Ibaraki

SaitamaTokyo
Kanagawa Chiba

Kanto Region
Introduction and backgroundKashiwa
MatsudoShiroi

Inzai

Kamagaya

The lake and surrounding cities
3

The lake and cities in the watershed
Lake Teganuma

City

Area
(km2)

Kashiwa
114.7
Inzai
123.8
Abiko
43.2
Shiroi35.5
Kamagaya
21.1
Nagareyama 35.3
Matsudo
61.4
Introduction and background6.5 km2
38 km
0.86 m
3.8 m
5.6 million m³
143.98 km2

Area
Circumference
Depth (average)
Depth (max)Water volume
Watershed area
Area in thewatershed (km2)

81.1
19.4
14.6
10.7
9.4
4.9
4.0

Watershed area
as % of city area

71 %
16 %
34 %
30 %
45 %
14 %
7%

Population(Dec 2021)

430,096
107,633
131,40262,726
109,871
204,846496,3504

Behind WQ degradation in the lake Residential development → Rapid population
growth without simultaneous sewerage systemdevelopment(110,000 in 1960 → 300,000 in 1975)
Shrinking the lake size due to reclamation
for paddy field development(became 40% smaller in the late 1960s)

Pollution load by source in 1985
Introduction and background

Teganuma Water Environment Conservation Council HP
http://www.tesuikyo.jp/?page_id=19255

Consequence of water quality degradation
 Reduction of aquatic plants and animals
 1960s: Anoxic conditions caused by blue-green algae
bloom led to extinction of water chestnut plant (generally
resistant to polluted water) and mass mortality of cruciancarp, catfish, thunderfish and eels; 1970s: Decline in the number of migrant birds;
 2000s: Extinction of fish species;(30 in 1956 survey  20 disappeared in 2004)
 Blue-green algae bloom → Impacts on water use
 Aesthetisity of landscape Fishery (decrease in catches) Recreation (decrease in visitors)
Abiko City Teganuma Division, "Creatures Living in Teganuma"
https://www.city.abiko.chiba.jp/event/shizennonaka/teganuma/ikimono.files/7 teganumanikurasuikimono.pdf

Introduction and backgroundPhoto: Photo collection at theTeganuma Division, Abiko City Hall
6

Water quality (CODMnconcentration)and population

600,000

Nedoshita
Introduction and background

Teganuma Chuo

Fusashita

2018

2015

2012

2009

2006

2003

2000

1997

1994

0

1991

0

1988

100,000
1985

5
1982

200,000

1979

10

1976

300,000

1973

15

1970

400,000

1967

20

1964

500,000

1961

25

Population

COD (mg/L)

30

Population in the watershed (est)7

Water quality(T-N and T-P concentrations)
T-N (mg/L)

10

1.0

8

0.8

6

0.6

4

0.4

Introduction and background

Teganuma Chuo

2012

2009

2006

2003

2000

1997

1994

1991

1988

Nedothita

Fusashita

1985

Nedoshita

Teganuma Chuo

1982

0.0

1979

0

0.2

Environmental standard
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
2009
2012
2015
2018

2

T-P (mg/L)

Fusashita8Addressing water degradation problems

P ublic adm inistration

Objective: Restoring Lake Teganuma as it was, by improving water quality(venue for recreation and water for agriculture and fishery)
Policy target: To meet the environmental standard

General process to address problems
Plan: Understanding issues and policy formulation“continue” and “revise” --> back to D
Do: Policy implementation
Check: Evaluating policies by examining achievement
Action: Determining to continue, revise, or abolish the policies
In the watershed, multiple administrative levels addressed the problem together. The
PDCA cycle started to function after decades of deterioration.
1: National level: Policy formulation for the water quality in the public water areas
2: Subnational levels: Developing and implementing measures at the watershed
Governance9

Important aspects of governance
Effective and good governance system: No standard governance system
System should be adapted to the social, economic, and cultural background ofeach country and region＊
Basic principles＊: Open and Transparency; Inclusive and Communicative;
Coherent and Integrative; Equitable and Ethical; Accountable; Efficient;
Responsive and Sustainable

Focus of the Teganuma case study Framework, roles and responsibilities, and collaboration
 Collaboration scale Monitoring, policy evaluation, revision, and goal setting＊ Rogers, Peter, and Alan W. Hall. Effective water governance. Vol. 7. Stockholm: Global water partnership, 2003.

Governance10Chronology: water degradation, policy
development, and improvement
Water quality
problemobserved
Development ofpolicies andmeasures toaddress the
problem(national andsubnational
levels)Water quality
improvement
observed
Historical review

1945

Reclamation project started

1955

Public swimming area closed due to unsuitable water quality

1960

Massive fish death
Development of the masterplan for the sewerage system (Kashiwa)
Blue-green algae bloom
Night soil treatment plant begun its operation (Kashiwa)
Basic Law for Environmental Pollution (WQ standards)

1965
1967
1969
1970

Began regular WQ monitoring
Water Pollution Prevention Act (effluent standards, classification)

1971

Launching the basin-wide sewerage system development

1973

Blue-green algae bloom
Wastewater treatment plant begun its operation (Kashiwa)
11

Chronology: water degradation, policy
development, and improvement
Water quality
problemobserved
Development ofpolicies andmeasures toaddress the
problem(national andsubnational
levels)Water quality
improvement
observed
Historical review

1974
1978
1981
1983

Recognized as the most polluted lake in Japan
Launching the Kita-Chiba headrace channel projectBlue-green algae in full bloom
Massive fish deaths and odor problems
The operation of the basin-wide sewerage system began

1987

Johkaso Act (a legal framework for decentralized system)
Act on Special Measures concerning Conservation of Lake
Water Quality (Lake Act) (Set the T-N and T-P standards)
Blue-green algae in full bloom
The lake designated as “designated lake” under the Lake Act
Formulation of the 1st “Lake Water Quality Conservation Plan”

1995
2000
2008

Signs of improving water quality (COD concentration decreased)
Supplying river water through the Kita-Chiba headrace channel
Growth inhibition of blue-green algae

1984
1985

Formulating the conservation plan every 5 years

12How the governance system established1950’s: Water degradation began
1960s Establishment of the basic legal framework (environmental and effluent
standards, etc.) (national)
Development of a masterplan for the sewerage infrastructure (subnational)
1970s Implementation of measures set in the legal framework (subnational)
Development of hard measures (national and subnational)
Implementation of soft measures at the household level (subnational)
1980s Development of legislation aiming to improve WQ of lakes (national)
Strengthened decentralized domestic wastewater treatment framework(national and subnational)
Lake conservation plans (subnational)
1990s-2000s: Evaluating policies by examining achievement and revise policies
and measures every five years (subnational)
Historical review

13Key policies to address the problem
Legal framework by the national government
Basic Law for Environmental Pollution (environmental
standards for public water)
Revisions areoccasionally made,by considering thesituation of public
waters nationwide

Water Pollution Prevention Act (effluent standards)
Amendment of Sewerage Act (domestic wastewater
management in urban areas)Johkaso Act (domestic wastewater management, mainly
outside urban areas)
Act on Special Measures concerning Conservation of
Lake Water Quality

Key policies and measures

14

Measures and policies in the watershed
Implemented by Chiba Prefecture, cities, and towns
in 1970’s (when the pollution problem progressed)
 Development of a masterplan for the sewerage system in cities
 Development of night soil and wastewater treatment plants Periodical water quality monitoring Development of the basin-wide sewerage system by Chiba
Prefecture Establishment of a “Teganuma Water Quality Purification
Council” and other organizations for collective action
Key policies and measures

15

Measures and policies in the watershed
Implemented by Chiba Prefecture, cities, and towns
after the problem became more serious
 Dredging of sludge (1976)
1979-1991

 Cleanup activities by citizens (removal of floating debris, cutting
plants harmful to water quality) (1976)

Gradual Promotion of phosphorus-free detergents (1979)
improvement of Constructed river and drainage purification facilities (1979)
water quality
 Planting water hyacinth for T-N and T-P removal (1981)
 Published a guideline for managing domestic wastewater
treatment by Chiba Prefecture (1982)
 Blue-green algae control by using pulling vessels (1982)
Key policies and measures

16

Measures and policies in the watershed
Implemented by Chiba Prefecture and cities
after pollutant loads began to decrease
1995-2005
Significant
water quality
improvement

 Partial operation of the Kita-Chiba headrace channel (draining
water from Teganuma to Tone River, 1983)
 Blue-green algae control by hydro-extractor machine (1985)
 Designated as a “designated lake” under the Lake Act (1985)→ Formulation of the lake water quality conservation plan (1st-7th
phases), Evaluation and revision done every 5 years
 Completion of the Kita-Chiba headrace channel for transferring
water from Tone River to Teganuma (2000)

WQ improved and people came back to the lake but the standard not met;
5-year evaluation and revision of the lake conservation plan continues today
Key policies and measures17

Changes in water quality
450000End of Phase II

400000Transferring river water
through the Kita-Chiba
headrace channel

35000030000025202500001520000015000010

100000

5
1960
1962
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018

50000
0

30

Population not covered by the sewerage in Kashiwa

Population covered by the sewerage in Kashiwa

T-N at Teganuma Chuo

COD at Teganuma Chuo

Key policies and measures

18

0

The lake water quality conservation plan

objectives

Phase I (1986-1990)
Teganuma is a valuable asset as areservoir for agriculture, inland water
fishery, and a place for recreation.
...
We will comprehensively plan andpromote balanced water quality
conservation measures such as
projects to conserve water and toaddress pollution problems.

Key policies and measures

Phase VII (2016-2020)

In the past, the lake was a rich fishing groundwith abundant aquatic organisms, and thewater was used for agriculture. Today,
Teganuma is still used for agricultural water,
and is also a valuable asset for inland fisheries
and recreation, and a place of rich culture
where many writers prepared theiroutstanding works.
...
Based on the natural and social environment,
and from the perspectives of restoring water
quality and quantity, biological habitats, andrelation between people and water, we aim to
restore the beautiful and rich Teganuma’s
environment and to achieve environmental
standards by 2030.
19

The lake water quality conservation planmeasures Basin-wide swerage development

 Utilization of river purification facilities

 Promoting the installation of advanced
Johkaso system Cleaning (removing debris), dredging

 Proper management at night soil
treatment facilities

 Restoring natural environment of river Transferring river water for purification

 Treating untreated domestic wastewater at  Maintenance of vegetation zones
community wastewater facilities
 Measures at household Pollution load control for livestock andfisheries
 Promoting development of livestock waste
treatment facilities
 Measures for wastewater from industry
and business
Key policies and measures Blue-green algae collection

 Runoff control (agricultural land andurban areas) Preservation of green space and thesurrounding natural environment
Underline : Measures not included in Phase I
20

Target and achievement(for evaluation)

Lake water quality
conservation plan

COD target
value

Value at the end ofphase

Phase I (1986-1990)

18 mg/L

19 mg/L

Phase II (FY1991-1995)

16 mg/L

29 mg/L

Phase III (1996-2000)

18 mg/L

15 mg/L

Phase IV (2001-2005)

13 mg/L

9.3 mg/L

Phase V (2006-2010)

8.5 mg/L

9.6 mg/L

Phase VI (2011-2015)

8.8 mg/L

9.3 mg/L

Phase VII (2016-2020)

9.0 mg/L

11 mg/L
Teganuma Chuo 75% Value

Policy evaluation

21

Target and achievement(for evaluation)

Lake water quality
conservation plan

T-N and T-P
targets

Phase I (1986-1990)

3.9 and 0.30 mg/L

5.3 and 0.51 mg/L

4.8 and 0.37 mg/L

3.2 and 0.26 mg/L

2.7 and 0.2 mg/L

2.8 and 0.17 mg/L

2.6 and 0.15 mg/L

2.5 and 0.16 mg/L

2.4 and 0.14 mg/L

2.1 and 0.13 mg/L

2.2 and 0.12 mg/L

2.3 and 0.17 mg/L

Phase II (FY1991-1995)
Phase III (1996-2000)
Phase IV (2001-2005)
Phase V (2006-2010)
Phase VI (2011-2015)
Phase VII (2016-2020)

Value at the end of
the phase

Teganuma Chuo annual average

Policy evaluation

22

Changes in pollution loads(for revising the plan)

COD load（kg/day）
7000

Population
6000006000

5000005000

4000004000

3000003000

2000002000

100000

1000
0

1985

1990

RunoffPolicy evaluation

1995
Industry

2000

2005

Domestic

2010

2015

2016

0

Population in the watershed
23

Changes in pollution loads(for revising the plan)

T-N load(kg/day)

Population

3000

6000002500

5000002000

4000001500

3000001000

200000500

100000

0

1985

1990

RunoffPolicy evaluation

1995
Industrial

2000

2005

Domestic

2010

2015

2016

0

Population in the watershed
24

Changes in pollution loads(for revising the plan)

Population

T-P load(kg/day)400

600000350

500000300

400000250

300000200
150200000100

100000

50
0

1985

1990
RunoffPolicy evaluation

1995
Industrial

2000

2005

Domestic

2010

2015

2016

0

Population in the watershed25

Lake Teganuma Today Water withdrawal for agriculture Inland water fishery (catch (carp, crucian carp,etc.): 109 ton in 2004 → 0 in 2019)
 Fishery association operates fish farms for sales
and recreational fishing Venue for recreation: Teganuma Park, Aquatic
Botanical Garden, Bird Museum, Biotope,
promenade, and other waterfront facilities Teganuma Triathlon and other sports events（370 participants in 2018 Triathlon)
Collection of Teganuma Division, AbikoCity Hall

Policy evaluation

26

Water Governance at Lake Teganuma

 Framework, roles and responsibilities, and collaboration

 Recognizing problems of public waterbody and establishing legal and implementation
framework by national government
 Formulate lake water quality conservation plans by subnational government Periodical monitoring to examine the water environment by subnational government
 Support for businesses and citizens in the watershed by subnational government
 Effective water quality conservation through information exchange (frequent communication
between national and subnational governments, established a council), Clarify citizens‘ role
(wastewater control at home and cleaning ditch) and their understanding Collaboration scale
Watershed-wide collaboration with the prefectural government (prefecture, 7 cities in thewatershed, and water users including citizens) Monitoring, policy evaluation, revision, and goal setting
Periodical monitoring and evaluation of the measures in the conservation plan every 5 years
Message from the case27

Water degradation and improvement
1955
1960
1965

Initial observation of water degradation
Signs of progressive water degradation
Implementation of series of policies andmeasures; Establishment of governancesystem (establishment of 5-year policy
evaluation and revision of measures by watershed wide stakeholders)

1995

Signs of improving water quality

2008

Growth inhibition of blue-green algae

Message from the case53 yearssince theinitialobservationof theproblem28

Message from the Teganuma case study Framework, roles and responsibilities, and collaboration-->inclusiveness, communication, responsibility, accountability, and efficiency
 Collaboration scale--> equity and ethic
 Monitoring, policy evaluation, revision, and goal setting-->openness, transparency, coherence, integrity, sustainability

This case presented how the water degradation was addressed thoughestablishing a governance system, such as building distinctive roles andresponsibilities of stakeholders. Setting the legal, institutional, andimplementing framework is just a starting point. While establishing thegovernance system, periodical evaluation of policies and revision of measuresby adapting to changing environmental and social conditions would lead toachieving a sustainable water environment in a region.
Message from the case29

Thank you

30