1. The water purification in L.Suwa.
The experiences and the problems of the
environmental rehabilitation of a lake
i t l h bilit ti f l k
诹访湖的水质净化
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
2. The profiles of L. Suwa(1)
诹访湖的概要
１．Origin of lake：Tectonic lake
（about 300 000
（ b t 300,000 years ago bi th）
birth）
The depth of the sedimentation：200ｍ<
２．Type lake Eutrophic
２ Type of lake：Eutrophic type
３． The specifications of lake：
Surface area：13 3 ㎞２
area：13.3
Lakefront line extension distance ：16㎞
Water depth：max. depth 6.5 ｍ
mean depth about 4 ｍ
Catchment area： 532 ㎞２
（ About 40 times of the surface area of lake ）
Retention time：about 40 days ( annual mean )
Characteristics of sediment ： diatom Gyttja
3. The profiles of L. Suwa(2)
p ( )
诹访湖的概要（2）
４．Humanistic characteristics：
Population ：about 200 000 capitals
200,000
Paddy and vegetable fields :
31% of catchment area
Urban area : 6 2% of catchment area
6.2%
Industry : Silk, clock, high technical and
fermentation industries ( high economic
p
power region in the inland of Japan)
g p )
4. The
Th past landscape of Lake Suwa. (around 1940)
tl d fL k S ( d
諏訪湖の今昔 ～かつての風景～
诹访湖的过去风景（大概1940年）
諏訪湖で水泳
Swimming in L Suwa
L. The landscape of water front
p
諏訪湖の湖畔
of L. Suwa
（ ( 1941６
昭和１ ) 年） （昭和初期）
(Around 1940)
2
5. The water pollution status of Lake Suwa.
( 1970~1973 ) 水污染情况
諏訪湖の今昔 ～昭和40年代～
September, 1970 July, 1972
昭和４ 年７ ７ 月
昭和４ 年９ ５ 月
昭和４ 1973 月
August, 年８
August８ 昭和４ 年９８ 月
September,
September 1973
3
6. Comparison of the blooming situation ( transparency of surface lake water)
アオコの発生状況
by blue-green algae between 1971 and 1999
1971年与1999年之间的水华情况（水面的透明性）的比较
August, 1971 月
昭和４ 年８ ６ 平成１1999 月
August,１年８
5
7. The present status of the remediation of water front and the
water quality of L. Suwa ( from spring to summer, 2000)
諏訪湖の今昔 ～現在～ 诹访湖的现状
remediation of beach remediation of water front
なぎさ整備 なぎさ整備
平成１ 年７ ２ 月
July, 2000 平成１ 2000 月
August, 年８
A t２
4
8. 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 )
No processing industry and domestic water flow into the lake
A 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 lake
2nd 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
nutrients ( nitrogen and phosphorus) f
i i d h h ) from the watershed of
h h d f
L. Suwa
Rapid
R id water pollution was generated, and a amount of th
t ll ti t d d t f the
blue-green algae occurred.
9. The recent progress of the environmental changes
in Lake Suwa（2）
近年的环境变化（2）
3rd stage : The start of the purification measures (the 1970's
d
beginning )
1) The setting of th environmental standard (l
Th tti f the i t l t d d (legal l
maintenance)
Industrial drainage regulation (heavy metals and organics )
2) The construction of the sewerage system
Industrial drainage and urban waste water regulation
3) Dredging of the polluted mud of lake bottom start ( littoral
zone,
zone 2m >)
4th stage : A new trial to purification ( mitigation ) (1990~ )
The development of the soft action by the inhabitants
participation
10. An administrative action to L. Suwa purification
为诹访湖净化的行政性行为
1965 Lake Suwa purification measure Committee start
The water pollution investigation of L Suwa start
L.
1969 The dredging of the litoral zone (2.5 m>) start
1971 Environmental standard setting about water pollution
1972 The sewerage system construction start
1979 The part service of the sewerage system start
1987 The application of the Law Concerning Special Measures
for Conservation of Lake Water Quality ( Nitrogen and
Phosphorus standard )
2002 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 q
creature (change of the aim )
11. Inhabitants and the administrative actions
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 2nd, 1993 3rd i G
d d in Germany, 2002 4th )
1994 A waterside maintenance examination committee
depending on i h bit t participation
d di inhabitants ti i ti
1995 Making the master plan for lakeside mitigation,
Start the reconstruction of the waterfront
12. The main scientific researches about Lake Suwa
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)
pref.
1967-1973 International Biological Programs (Monbusyo)
1971-1975 UNESCO Man and Biosphere (Monbusyo)
UNESCO,
1977-1985 Special Program of Environmental Sciences
(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 (
p g g (Ministry of
y
Environment, Shinshu University)
13. New development to purification action
Revive; Lake Suwa →Swimming in L. Suwa
为净化新的开展
从‘恢复诹访湖’到‘在诹访湖游泳’
The
Th switch of the aim : lake water purification
it h f th i l k t ifi ti
→ conservation of lake ecosystem
*The restoration of the bank becomes the key to
Suwa lake quality p
q y purification
(Development of mitigation action )
The holding of the joint seminars of Japan and
Germany(1989~2002) by the sponsorship of
inhabitants was a chance
chance.
*Inhabitants, an expert, administrative cooperation
and appropriate role allotment
d i t l ll t t
24. A waterfront maintenance business :
Master plan of L. Suwa マスタ
諏訪湖 水辺整備事業（ ） １ ープラン
水边维护商业 诹访湖的总体设计
＜水辺整備のテ マ＞
＜水辺整備のテーマ＞
The scenery of the new L.Suwa ・Shore reconstraction to bring up nature and culture
新たな諏訪湖の風景・自然そして文化を育む湖畔づくり
Reconstruction and creation of the shore environment that assumed Lake Suwa at
the time ―― 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 ――
of 1950 original scenery
g y
水上ス ーツ 楽し
ポ を む湖畔
Ｈ
Ｇ
湖面に浮かぶ自然と共生する湖畔 湖の風景を む湖畔
楽し
Ｆ
Ｅ
水辺の生物と の交流を 湖畔
人と する
Ｄ
釜口水門・
大噴水を ン
シ ボルと た憩いの湖畔
し
A
賑わい ふれあい
と の湖畔
Ｃ
Ｂ
広々と た湖の風景を
し 満喫する湖畔
水辺の生物豊かな湖畔
水辺整備ゾーニング図
17
31. The floating plants (Trapa sp.)zone reconstructed
naturally in the front of the artificial beach
自然に再生した浮葉植物帯（ヒシ群落）
在人造的岸边的前面，漂浮性植物自然地恢复了
32. The trees and the bridge of the walking road of
湖畔遊歩道の植栽と遊歩道専用の橋
lake side 湖边步行路的树木与桥梁
33. Case A zone : The beach where a person can
p
Ａゾーンwater
touch the ～賑わいとふれあいの湖畔～
A地区（这座岸边的水能触到）
施工前
Before
B f After
施工後
34. The reproduction situation of the submerged plant
in L. Suwa
水生植物的恢复情况
400
350
300
250
200 分布面積
クロモ現存量
150
100
50
0
1911 1966 1972 2006
35. The change of the total phosphorus
concentration in L Suwa (Nagano Pref 2007)
L. Pref.,2007)
总磷浓度的变化（长野县，2007）
P mg/l
0.35
0.3
03
0.25
The part service start of the sewer(1979)
0.2
0.15
0 15
Standard TP：0.05mg/l
0.1
0.05
0S48 50 52 54 56 58 60 62 1 3 5 7 9 11 13 15 17
36. The change of the total nitrogen concentration in L.
Suwa (Nagano Pref 2007)
Pref.,2007)
总氮浓度的变化（长野县，2007）
N mg/l
2.5
2
The part service start of the sewer(1979)
1.5
1
0.5
05 Standard TN0 6 /l
St d d TN0.6mg/l
0
S48 51
1 54 57 60
0 63 3 6 9 12
1 15
1 18
1
37. The change of COD concentration in L. Suwa
(Nagano P f 2007)
(N Pref.,2007)
COD浓度的变化（长野县，2007）
COD mg/l
10
The part service start of the sewer(1979)
8
6
4
2 Standard COD：3 mg/l
0
1
2
4
6
8
43
45
47
49
51
53
55
57
59
61
63
10
12
14
16
18
S4
38. 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．
２ Promotion of the area along the shore
・ Hydrophilic creation and maintenance by the reconstruction
of the natural landscape
・ Th aquatic floral zone reconstruction of the area along the
The ti fl l t ti f th l th
shore
３． Local inhabitants and user promote adequacy of a lake use
under the agreement
d th t
・ 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 region
39. A problem of the aquatic
environment improvement
p
水环境改善活动中的问题
Inhabitants The information di t h
Th i f ti dispatch
Information disclosure
from inhabitants
by the administration
Understanding Information disclosure and a
of nature commentary by the expert
Government Expert
An exhibition and joint ownership of the information
The coexistence of a person and the creature
Conservation Know ridge
Aquatic organisms
Protetion Understanding
Creation f the t
C ti of th water culture as new culture
lt lt
40. The lesson that Lake Suwa conveys
诹访湖所传达的教训
１．Restoration is the next best thing : It is the most
g
important 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．「
２ 「 Coexistence with the other creatures in nature 」is
the most important idea
＊ It is human arrogance to think that we can do it
g
by human power everything
３． There is not the creature living under the most
suitable environment
it bl i t
＊ Earth is not nature only in human sake
＊Patience and hesitation are necessary so that we
survives
41. よみがえれ諏訪湖
み ; れ諏訪湖
Revive; Lake Suwa
春 夏
秋 冬
泳げる諏訪湖から飲める諏訪湖
泳げる諏訪湖から飲める諏訪湖へ
諏訪湖を飲もう
Ｆｎ
ｉ
50
