The water purification in L.Suwa.The experiences and the problems of the

i t l h bilit ti f l kenvironmental rehabilitation of a lake诹访湖的水质净化

环境复原的实践与问题环境复原的实践与问题

Tokio Okino 冲野外辉夫

(Professor emeritus, Shinshu University)信州大学名誉教授

The profiles of L. Suwa(1)诹访湖的概要诹访湖的概要

１．Origin of lake：Tectonic lake（ b t 300 000 bi th）（about 300,000 years ago birth）The depth of the sedimentation：200ｍ<

２ Type of lake Eutrophic type２．Type of lake：Eutrophic type３． The specifications of lake：

Surface area：13 3 ㎞２Surface area：13.3 ㎞Lakefront line extension distance ：16㎞Water depth：max. depth 6.5 ｍWater depth：max. depth 6.5 ｍ

mean depth about 4 ｍCatchment area： 532 ㎞２

（ About 40 times of the surface area of lake ）Retention time：about 40 days ( annual mean )

Characteristics of sediment ： diatom Gyttja

The profiles of L. Suwa(2)p ( )诹访湖的概要（2）

４．Humanistic characteristics：Population ：about 200 000 capitalsPopulation ：about 200,000 capitalsPaddy and vegetable fields :

31% of catchment areaUrban area : 6 2% of catchment areaUrban area : 6.2% of catchment areaIndustry : Silk, clock, high technical and

fermentation industries ( high economic power region in the inland of Japan)p g p )

Th t l d f L k S ( d 1940)諏訪湖の今昔 ～かつての風景～

The past landscape of Lake Suwa. (around 1940)诹访湖的过去风景（大概1940年）

諏訪湖で水泳諏訪湖で水泳 諏訪湖の湖畔諏訪湖の湖畔Swimming in L Suwa The landscape of water front 諏訪湖で水泳諏訪湖で水泳

（昭和１６年）（昭和１６年）

諏訪湖の湖畔諏訪湖の湖畔

（昭和初期）（昭和初期）

Swimming in L. Suwa

( 1941 )

pof L. Suwa

(Around 1940)

2

The water pollution status of Lake Suwa.諏訪湖の今昔～昭和40年代～

The water pollution status of Lake Suwa. ( 1970~1973 ) 水污染情况

昭和４５年９月昭和４５年９月 昭和４７年７月昭和４７年７月September, 1970 July, 1972

昭和４８年８月昭和４８年８月 昭和４８年９月昭和４８年９月August 1973 September 1973

3

昭和４８年８月昭和４８年８月 昭和４８年９月昭和４８年９月August, 1973 September, 1973

アオコの発生状況Comparison of the blooming situation ( transparency of surface lake water) by blue-green algae between 1971 and 19991971年与1999年之间的水华情况（水面的透明性）的比较

昭和４６年８月 平成１１年８月August, 1971 August, 1999

5

The present status of the remediation of water front and the

諏訪湖の今昔～現在～water quality of L. Suwa ( from spring to summer, 2000)诹访湖的现状

なぎさ整備なぎさ整備 なぎさ整備なぎさ整備remediation of beach remediation of water front

平成１２年７月平成１２年７月 平成１２年８月平成１２年８月A t 20004

平成１２年７月平成１２年７月 平成１２年８月平成１２年８月July, 2000 August, 2000

The recent progress of the environmental changes in Lake Suwa（１）

近年的环境变化(1)

1st stage : A silk thread industry seedtime ( around 1900 )

近年的环境变化(1)

No processing industry and domestic water flow into the lakeA large quantity of earth and sand flow into the lake from the mountain region by felling of the forest

There was not the change of the appearance-like lake2nd stage : A highly economic period of growth (1960~)Complicated water pollution occurred by the various

pollutants (industry, urban, agriculture, etc.)Eutrophication of lake water by inflowing of a large amount of

i ( i d h h ) f h h d fnutrients ( nitrogen and phosphorus) from the watershed of L. SuwaR id t ll ti t d d t f thRapid water pollution was generated, and a amount of the blue-green algae occurred.

The recent progress of the environmental changes in Lake Suwa（2）

d

in Lake Suwa（2）近年的环境变化（2）

3rd stage : The start of the purification measures (the 1970's beginning )

1) Th tti f th i t l t d d (l l1) The setting of the environmental standard (legal maintenance)

Industrial drainage regulation (heavy metals and organics )Industrial drainage regulation (heavy metals and organics )2) The construction of the sewerage systemIndustrial drainage and urban waste water regulationIndustrial drainage and urban waste water regulation

3) Dredging of the polluted mud of lake bottom start ( littoral zone 2m >)zone, 2m >)

4th stage : A new trial to purification ( mitigation ) (1990~ )The development of the soft action by the inhabitantsThe development of the soft action by the inhabitants participation

An administrative action to L. Suwa purification为诹访湖净化的行政性行为为诹访湖净化的行政性行为

1965 Lake Suwa purification measure Committee startThe water pollution investigation of L Suwa startThe water pollution investigation of L. Suwa start

1969 The dredging of the litoral zone (2.5 m>) start1971 Environmental standard setting about water pollution1971 Environmental standard setting about water pollution1972 The sewerage system construction start 1979 The part service of the sewerage system start1979 The part service of the sewerage system start1987 The application of the Law Concerning Special Measures

for Conservation of Lake Water Quality ( Nitrogen andfor Conservation of Lake Water Quality ( Nitrogen and Phosphorus standard )

2002 The targeted value of the fourth plan : COD 4.7ppm,TP2002 The targeted value of the fourth plan : COD 4.7ppm,TP 0.05 mg/l, TN 0.75 mg/l

2007 Revive; Lake Suwa →Lake Suwa coexisting with aquatic g qcreature (change of the aim )

Inhabitants and the administrative actions为诹访湖净化的行政性与居民的行为为诹访湖净化的行政性与居民的行为

1973 The shore cleaning by the students of Kamisuwa Middle School start (spring and summer)

1975Public hall activity in the watershed area (A general theme :The environmental problems)

1985 The shore cleaning action by the inhabitants of 2 cities and 1town around the lake

1989 The 1st environmental urban designing with Japan and Germany in Suwa

( 1991 2 d 1993 3 d i G 2002 4th )( 1991 2nd, 1993 3rd in Germany, 2002 4th )1994 A waterside maintenance examination committee

d di i h bit t ti i tidepending on inhabitants participation

1995 Making the master plan for lakeside mitigation, Start the reconstruction of the waterfront

The main scientific researches about Lake Suwa关于诹访湖的主要科学研究关于诹访湖的主要科学研究

1965-1968 The study of the purification measure of L. Suwa(Nagano pref and Shinshu university)(Nagano pref. and Shinshu university)

1967-1973 International Biological Programs (Monbusyo)1971-1975 UNESCO Man and Biosphere (Monbusyo)1971-1975 UNESCO, Man and Biosphere (Monbusyo)1977-1985 Special Program of Environmental Sciences

(Monbusyo)(Monbusyo)1985-1988 Ecosysetm Studies of Littoral Zone of L. Suwa

(Monbusyo)( y )1990-1998 The studies on the matter cycles of lake littoral

(The studies on the reproduction of aquatic organisms)(Ministry of Agriculture, Nagano Pref., Shinshu Univ.)

1996-present Long-term monitoring of L. Suwa (Ministry of p g g ( yEnvironment, Shinshu University)

New development to purification actionRevive; Lake Suwa →Swimming in L. Suwa

为净化新的开展为净化新的开展从‘恢复诹访湖’到‘在诹访湖游泳’

Th it h f th i l k t ifi tiThe switch of the aim : lake water purification → conservation of lake ecosystem

*The restoration of the bank becomes the key to Suwa lake quality purification q y p

(Development of mitigation action )The holding of the joint seminars of Japan andThe holding of the joint seminars of Japan and

Germany(1989~2002) by the sponsorship of inhabitants was a chanceinhabitants was a chance.

*Inhabitants, an expert, administrative cooperationd i t l ll t tand appropriate role allotment

3rd seminer in GermanyGermany (June, 1993)

第3回 日独環境まちづくりセミナ第3回 日独環境まちづくりセミナー（1993年6月：シュタルンベルク湖）

A waterfront maintenance business :諏訪湖 水辺整備事業（１）マスタープラン

＜水辺整備のテーマ＞

諏訪湖 水辺整備事業（１）マスタープラン

＜水辺整備のテーマ＞

Master plan of L. Suwa水边维护商业 诹访湖的总体设计

＜水辺整備のテ マ＞

新たな諏訪湖の風景・自然そして文化を育む湖畔づくり

―― 昭和30年当時の諏訪湖を原風景とした湖畔環境の再生と創造 ――

＜水辺整備のテ マ＞

新たな諏訪湖の風景・自然そして文化を育む湖畔づくり

―― 昭和30年当時の諏訪湖を原風景とした湖畔環境の再生と創造 ――

The scenery of the new L.Suwa ・Shore reconstraction to bring up nature and cultureReconstruction and creation of the shore environment that assumed Lake Suwa at the time of 1950 original sceneryg y

ＧＨ

湖面に浮かぶ自然と共生する湖畔

水上スポーツを楽しむ湖畔

湖の風景を楽しむ湖畔

ＧＨ

湖面に浮かぶ自然と共生する湖畔

水上スポーツを楽しむ湖畔

湖の風景を楽しむ湖畔

A

Ｄ

Ｆ

Ｅ

釜口水門・大噴水をシンボルとした憩いの湖畔

水辺の生物と人との交流をする湖畔

A

Ｄ

Ｆ

Ｅ

釜口水門・大噴水をシンボルとした憩いの湖畔

水辺の生物と人との交流をする湖畔

A

Ｂ

Ｃ

賑わいとふれあいの湖畔

広々とした湖の風景を満喫する湖畔

A

Ｂ

Ｃ

賑わいとふれあいの湖畔

広々とした湖の風景を満喫する湖畔

17

水辺の生物豊かな湖畔

広々とした湖の風景を満喫する湖畔

水辺整備ゾーニング図17

水辺の生物豊かな湖畔

広々とした湖の風景を満喫する湖畔

水辺整備ゾーニング図

Ｆゾーン ～湖面に浮かぶ自然と共生する湖畔～Case F zone : The shore that kept nature aliveF地区 与自然共生的湖畔

諏訪湖 水辺整備事業（２）湖岸植生の回復状況The recovery situation of the lakefront vegetation湖边植物的恢复情况

18施行前（平成５年） 施行後（平成７年）Before reconstruction (1993) After completion (1995)

修復工事直後Just after restoration construction恢复施工后的情况

修復2年後のマコモ群落内Aquatic plants community two years later

湖岸の再生（ふれあいなぎさ）Reproduction of the lakefront 1 (The beach where a person 湖岸の再生（ふれあいなぎさ）

p ( pcan touch the water) 湖边的复原1 （这座岸边的水能触到）

施工前 施工後Before After施 前 施 後

湖岸 再生（高浜なぎさ）湖岸の再生（高浜なぎさ）Reproduction of the lakefront 2 (Takahama beach)湖边的复原2 （高滨岸边）湖边的复原2 （高滨岸边）

施工前 施工後Before After施 前 施 後

湖岸の再生（渋崎なぎさ）Reproduction of the lakefront 3 (Sibusaki beach)湖岸の再生（渋崎なぎさ）Reproduction of the lakefront 3 (Sibusaki beach)湖边的复原3 涩崎岸边

施工前 施工後Before After施工前 施工後Before After

自然に再生した浮葉植物帯（ヒシ群落）The floating plants (Trapa sp.)zone reconstructed naturally in the front of the artificial beach在人造的岸边的前面，漂浮性植物自然地恢复了在人造的岸边的前面，漂浮性植物自然地恢复了

湖畔遊歩道の植栽と遊歩道専用の橋The trees and the bridge of the walking road of lake side 湖边步行路的树木与桥梁

Case A zone : The beach where a person can Ａゾーン ～賑わいとふれあいの湖畔～

ptouch the waterA地区（这座岸边的水能触到）

施工前 施工後B f After施工前 施工後Before After

The reproduction situation of the submerged plant in L. Suwa

水生植物的恢复情况

350

400

250

300

200

250

分布面積

クロモ現存量

100

150クロモ現存量

0

50

01911 1966 1972 2006

The change of the total phosphorus concentration in L Suwa (Nagano Pref 2007)concentration in L. Suwa (Nagano Pref.,2007)

总磷浓度的变化（长野县，2007）P mg/l

0 3

0.35P mg/l

0.25

0.3

The part service start of the sewer(1979)

0 15

0.2The part service start of the sewer(1979)

0.1

0.15

Standard TP：0.05mg/l

0

0.05

0S48 50 52 54 56 58 60 62 1 3 5 7 9 11 13 15 17

The change of the total nitrogen concentration in L. Suwa (Nagano Pref 2007)Suwa (Nagano Pref.,2007)

总氮浓度的变化（长野县，2007）N mg/l

2.5N mg/l

2The part service start of the sewer(1979)

1

1.5

0 5

1

St d d TN0 6 /l

0

0.5

1 0 1 1 1

Standard TN0.6mg/l

0S48 51 54 57 60 63 3 6 9 12 15 18

The change of COD concentration in L. Suwa (N P f 2007)(Nagano Pref.,2007)

COD浓度的变化（长野县，2007）COD mg/l

8

10COD mg/l

The part service start of the sewer(1979)

6

8

4

2 Standard COD：3 mg/l

0

S41 43 45 47 49 51 53 55 57 59 61 63 2 4 6 8 10 12 14 16 18

The problems of Lake Suwa诹访湖所面临的问题

１．The further improvement of the water qualities・None-point sources measure of the pollutants・Recovery of the self-purification power (river and soil)

２ Promotion of the area along the shore２． Promotion of the area along the shore・ Hydrophilic creation and maintenance by the reconstruction

of the natural landscapeTh ti fl l t ti f th l th・ The aquatic floral zone reconstruction of the area along the shore

３． Local inhabitants and user promote adequacy of a lake use d th tunder the agreement

・ Careful to the use in the coast landside (We need sight, the evaluation for the five senses including the hearing)

４． Ecosystem maintenance (coexistence with the other creatures in nature) as the Lake Suwa・ Careful to the introduction of the creature from other regionCareful to the introduction of the creature from other region

A problem of the aquaticenvironment improvement

水环境改善活动中的问题p

水环境改善活动中的问题

Th i f ti di t hInformation disclosure by the administration

Inhabitants The information dispatch from inhabitants

Information disclosure and aUnderstanding

Government Expert

Information disclosure and a commentary by the expert

Understanding of nature

An exhibition and joint ownership of the informationGovernment Expert

The coexistence of a person and the creature

Aquatic organismsConservation

Protetion

Know ridge

Understanding

The coexistence of a person and the creature

C ti f th t lt lt

Protetion Understanding

Creation of the water culture as new culture

The lesson that Lake Suwa conveys诹访湖所传达的教训诹访湖所传达的教训

１．Restoration is the next best thing : It is the most gimportant not to break a certain nature＊ There are few expenses and finishes it＊ There are little both time and labor and can achieve a purpose surely

２ 「 Coexistence with the other creatures in nature 」is２．「 Coexistence with the other creatures in nature 」is the most important idea＊ It is human arrogance to think that we can do it gby human power everything

３． There is not the creature living under the most it bl i tsuitable environment

＊ Earth is not nature only in human sake＊Patience and hesitation are necessary so that we＊Patience and hesitation are necessary so that we survives

Revive; Lake Suwaよみがえれ諏訪湖;み れ諏訪湖

春 夏

秋 冬

泳げる諏訪湖から飲める諏訪湖へ泳げる諏訪湖から飲める諏訪湖

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