KN-12

Conservation and Restoration
of Lakes and wetlands
K.K.Vass
Central Inland Fisheries Research Institute,
Barrackpore, Kolkatta , India.
Structure
¾General status
¾Concerns
¾Why conserve
¾Restoration
Lakes and wetlands
Lakes and wetlands are
ecosystems whose formation,
processes and characteristics
are determined by water
These ecosystems are
diverse, both in terms of
physico-chemical, biological,
and socio-economic
characteristics as well as
geographical distribution
Floodplains, marshes, deltas,
swamps, peat lands, bogs,
reservoirs, rivers and lakes
are all types of wetlands
Lake
A lake (from Latin ligacus) is a body of water of
considerable size contained on a body of land.
Relatively large body of slow-moving or standing
water that occupies an inland basin.
Inland body of standing water occupying a hollow in
the earth's surface.
Wetlands definition
According to Ramsar Convention (Article 1.1), wetlands
are defined as “areas of marsh, fen, peat land or water,
whether natural or artificial, permanent or temporary,
with water that is static or flowing, fresh, brackish or salt,
including areas of marine water, the depth of which at low
tide does not exceeds six meters”.
In addition, the Ramsar Convention (Article 2.1) provides
that wetlands “may incorporate riparian and coastal zones
adjacent to the wetlands, and islands or bodies of marine
water not deeper than six meters at low tide lying within
wetlands”.
Classification of wetland types
(Ramsar Convention)
1) Lacustrine wetlands (wetlands associated with lakes)
2) Riverine or floodplain wetlands (wetlands along river or
streams),
3) Palustrine (marshes, swamps, and bogs)
4) Marine (coastal wetlands, including rocky shores and coral
reefs)
5) Estuarine (including deltas, tidal marshes and mangroves)
6) Artificial water bodies (fish ponds, reservoirs and artificial
lakes).
It is generally understood that wetlands occupy the transitional
zone between permanently wet and generally dry environments.
MAIN FEATURES
¾ Lakes/Wetlands of all sizes and morphometric
characters
¾ Both Open and Closed
¾ Formed through natural and manmade processes
¾ Most of these have heavy component of
macrophytes
¾ Have both onsite and offsite benefits
¾ Have multi-user operations
¾ Large human settlements around them
¾ Urban and Peri-Urban settings
Distribution of lakes and wetlands over the world
. Colour code is the percentage coverage by a pixel height of 1 degree, i.e. 1 nm2 or 3.43 km2.
(Darras et al. 1998)
Fresh water covers approximately 8% of terrestrial surface
Only 10% of world’s lakes are located in the tropics
Global view on water and fish production
frozen
ground
lakes
saline
soil moisture
rivers
atmosphere
World's water resources
Inland
water
2%
frozen
88 %
Inland water
ground
12 %
saline
0.31 %
Fish species
Capture
Aquaculture
Total production
atmosphere
0.04 %
rivers
0.004 %
Other
1%
lakes
0.38 %
Oceans
98 %
Oceans
60 %
80 %
5%
85 %
soil
moisture
0.20 %
Inland waters
40 %
9%
6%
15 %
Tropical lakes
0.04 %
Size and depth distribution of tropical lakes
•
•
•
•
Natural lakes in the tropics are rare except for Africa (Rift Valley)
Asia and South America possess few natural lakes but have many reservoirs
Based on water surface alone Africa seems to have large potential for enhancements
Swamps, floodplains, shallow lakes and reservoirs = 57% of the total water surface area
Lakes vs. reservoirs
Characteristics
Lakes
Qualitative (absolute) difference
Nature
natural
Geological age
old
Aging
slow
Formed by
depressions
Shape
regular
Shore development ratio
low
Maximum depth
near centre
Bottom sediments
autochthonous
Gradients
wind-driven
Outlet
surface/none
Quantitative (relative) difference
Ratio watershed/lake area low
Retention time
high
Coupling with watershed
less
Morphometry
U-shaped
Level fluctuations
less
Hydrodynamics
more regular
Cause of pulses
natural
Reservoirs
man-made
young
rapid (first few years)
river valleys
dendritic
high
extreme (at the dam)
allochthonous
flow-driven
deep
high
low
great
V-shaped
great
highly variable
man-made drawdowns
Major wetland/lake resources in India
Assam
West Bengal
Bihar
Uttar Pradesh
Uttarakhand
Himachal
Jammu & Kashmir
North East States
Coastal States
The biological base for productivity
Food webs are often shorter in the tropics:
Tropical lakes
Temperate lakes
Fish
B
A
Phytoplankton
A = Crustacea
B = Rotifera and
Protozoa
Bacteria
Detritus
Fish
B
A
Phytoplankton
Bacteria
Detritus
WATER RESOURCES
RIVERS
WETLANDS & FLOODPLAINS
LAKES/LAGOONS
ESTUARIES
RESERVOIRS
Area estimates of wetlands in India excluding
rivers and canals (in million ha)
Area under paddy cultivation
40.9
Area suitable for fish culture
3.6
Area under capture fisheries (brackish and
freshwater)
2.9
Mangroves
0.4
Estuaries
3.9
Backwater
3.5
Man-made impoundments
3.0
Rivers, including main tributaries
(28,000 km)
Canals and irrigation channels
(113,000
km)
Total Area of Wetlands (Excluding Rivers)
58.2 mill. ha
(Source: Directory of Asian Wetlands, IUCN, 1989).
Trophic classification
Measured parameter
Oligotrophic Mesotrophic
Eutrophic
Total Phosphorus
(mg/m3)
3 - 18
10 - 95
16 – 386
Chlorophyll a (mg/m3)
0.3 - 5
3 – 11
3 – 78
Secchi Disk Depth (m)
5 - 28
2–8
0.8 – 7
Data from Wetzel, 1983
Above classification is important
tool in Management strategy.
CONCERNS
Rapidly deteriorating
Since 1900, more than half of the world such water bodies have disappeared
About 50,000 ha area of wetlands / lakes is degraded every year in Asia
There are many stakeholders whose diverse interest lay claim on the
ecosystem function
Agricultural producers drain and convert them to agricultural land
Water abstraction for drinking, irrigation, industries and human
settlements.
Soil acidification, erosion, nutrient loss
Hydrological changes
Loss of biodiversity and ecosystem functions.
Concerns contd…
Majority Neglected ecosystems with very little or no management inputs
Common Property Resources, for everyone to use but none to pay for
services and take care.
Reclaimed and transformed into unplanned urban, agricultural or aqua
culture production sites causing huge economic and ecological damage and
loss in the long-term
70-80% of the wetlands in the Ganga basin have been lost in the last 50 years
Rate of wetland loss in India is at 2 to 3% of area every year
Mangrove wetlands have reduced from 700,000 ha. to 453,000 ha. in India
Lack of co-ordination and complicity and contradictory objectives of policies
have led to unwise, unsustainable and destructive exploitation of wetlands
Destructive Fishing & De-silting a lake
Causes for loss
About 12% of wetland loss is through hunting and
associated disturbances
About 22% were lost to human settlements
19% to fishing and associated disturbances
25% through drainage for agriculture
Soil erosion and siltation contribute to over 12 % of
wetland loss
Nearly 10 % due to pollution from industries
Pollution Load from Domestic & Industrial Sources
25000
(63%)
Domestic
20000
Industrial
15000
(37%)
(68%)
10000
(32%)
5000
(66%)
(34%)
0
Wastewater(MLD)
BOD(t/d)
BOD reduction(t/d)
Metal Contamination in Different
Components
Metal Levels (μg g-1)
Components
Hg
Zn
Cu
Pb
Cd
Water
0.01 – 0.37
14 – 363
1 – 26.3
12.4 – 63.1
3.3 – 5.6
Macrophytes
(different
types)
1.65 – 3.04
68 – 310
NE
NE
NE
Fishes
(mainly
carps)
0.075 – 0.370
11.5 – 37
NE
NE
NE
Sediment metals in Indian rivers (ppb)
Zn
120
Cu
100
80
•
Metals levels in water and sediments are
moderate, except near pollution zones.
• Concentration of some organochlorine
pesticides in water are above permissible
limits
• Metals and pesticides in fish flesh are within
the safe levels.
• Some pesticides and metals get
biomagnified in food-chain to high levels
60
40
20
0
Ganga
Mahanadi Godavari Krishna
Cauvery Narmada
River
Total
residue
(ppt)
Permissible
limit exceeded
by
Ganga
river
system
17 - 80
4,4’-DDT
aldrin
dieldrin
Biomagnification of DDT in aquatic food chain
(ppb)
Organochlorine pesticides in fish of river Ganga
120
Bivalve
950
100
Plankton
150
Fish
450
Gastropod
220
R e s id u e c o n c . in p p b
Water
0.06
Sediment
70
80
60
40
20
0
L. dero
L. dero
C. mrigala R. rita
Rishikesh Hardwar Farukhabad Kanauj
Residue (ppb)
17
23
45
74
R. rita
C. garua
R. rita
Kanpur
Varanasi
Patna
33
100
26
A. aor
R. rita
A. gagora
Farakka Barrackpore Haldia
74
90
16
Sectors contributing to modification of lakes/wetlands
Anthropogenic Activities
Industrial
Domestic
Agriculture
Urbanization
Discharges to Wetlands
√
√
√
√
Non-point Source Pollution
√
√
√
√
Air pollutants
√
X
X
√
Toxic chemicals
√
√
√
X
Deposition of fills
√
√
√
√
Construction
X
√
√
√
Crop production
X
X
√
X
Siltation
√
√
√
√
Changing nutrient levels
√
√
√
X
Tourism/ recreational
X
X
X
√
Physical modification
√
√
√
√
WHY CONSERVE THESE WATERS ?
These
critical resources are
important for :
Providing ecosystem services,
livelihoods & cultural services
Through
the
provision
of
regulating services and products
which generate socio-economic
benefits they are vital to the
livelihood strategies of local
communities
These different services vary from
site to site, especially with the
type of wetland
REGULATING SERVICES
>Water storage
>Groundwater recharge & discharge
>Flood control & river regulation
>Water purification
>Sediment retention
>Climate regulation
LIVELIHOOD SERVICES
>Water supply - domestic & animals
>Agriculture resources
>Fisheries
>Forage resources
>Craft materials
>Medicinal plants
CULTURAL SERVICES
>Biodiversity
>Cultural sites
>Tourism
>Human settlement
Stakeholders
Goods & Services
¾
¾
¾
¾
¾
¾
¾
¾
Fishers
Agriculture Farmers
Water Managers
Local Community
Recreation
Transport
Eco-Tourism
Jute Industry
Economic value of wetlands
When wetlands are drained or degraded, there is a
financial cost incurred by society to replace the
ecological goods and services provided by these
ecosystems, such as
> Increased water treatment costs
> Increased illness and health care costs
¾ Shortage in irrigation water
¾ Water hauling and making deeper wells
> Increased insurance costs due to flood damages
> Decreased property value due to degraded
aesthetic qualities
> Decreased swimming/fishing opportunities
> Decreased revenues from tourism activities
associated with healthy ecosystems
Cultivation of Makhana in
wetlands, a gainful employment
in parts of Bihar and UP.
Lotus seeds from
wetlands; means of
livelihood from weed
choked wetlands in
Bihar. Lotus rhizome
used as vegetable in
Kashmir lakes- good
trade.
Harvesting Trapa from a wetland in Bihar;
additional livelihood for fishers
Gastropods form a sizeable portion of the benthic
fauna in wetlands. Species like Pila/Belamya
harvested from wetlands being consumed by local
people.
Lakes / Wetlands being used as channels
for
transportation
often
causing
environmental disturbance
Fishing & Fishery in Lakes / Wetlands
Subsistence fishing support
livelihoods of hundreds of
people living around lakes/
wetlands, especially women
and children
Fishing with plunging net, a common sight
In wetlands of Assam, in the northeast India
A variety of fishing methods are being used
to fish from wetlands
Fishing in a wetland for Indian
major carps using drag net
Indian major carps are being
regularly stocked and fished
when they reach harvestable
size (>200g) in wetlands,
which are managed by cooperative societies in
West Bengal and Assam
Wild - Fishing and Pollution
Fish Marketing
Man made floating islands, made of aquatic vegetation, in
Loktak lake, Manipur. A local contraption for aggregating
and capturing fishes.
Several people live in huts built on these floating islands
Majority of the lakes/
wetlands in the
country are weed
infested, affecting
their productivity.
Paddy
cultivation
along the marginal
areas of wetlands in
Bihar, West Bengal
cause encroachment
and reduction in water
spread.
Jute retting, a cause for degrading water quality
in several wetlands in West Bengal.
Jute cultivation bring additional income and
firewood/thatching material for fishers’ housing
Major Fishes of food value
Catla catla
Cirrhinus mrigala
Three Indian major carps being
stocked in wetlands under culture
based fishery management
Labeo rohita
Minor Fishes of food value
Channa punctatus
Channa marulis
Anabas testudineus
Badis badis
Ornamental fishes
Colisa lalia
Colisa sota
Devario devario
Chanda nama
Ornamental fishes
Puntius conchonius
Rasbora daniconius
Tetradon cutcutia
Rasbora rasbora
Production (000 t)
State
Area (ha) Existing Potential
West Bengal
42.5
9.56
53.15
Bihar
40
4.80
30.00
Assam
100
12.00
95.00
Uttar Pradesh
152
22.80 114.00
Other NE states
Total
19.2
353.7
1.49
50.65
% Projected
Gap increase Increase
43.59 455.96 4.6 fold
25.20 525.00 5.3 fold
83.00 691.67 6.9 fold
91.20 400.00
4 fold
15.78 14.29
307.93 257.28
959.06
507.96
9.6 fold
5 fold
Production enhancement methods
Environmental impact
Production potential per unit area versus spatial scale of production units of the
various methods used in lakes and reservoirs. Arrow indicates the perceived
increased environmental impacts moving from natural harvest to intensive
culture. (Ranges of production are tentative)
Sustainable Fishery Development
System Analysis
¾
¾
¾
Production Function Estimates
Biodiversity Assessment
Identification of Interventions
Fishery Enhancement
¾
¾
Stock Manipulation
Pen-culture & Cage-culture
Awareness & Participation
Network Formation
Economic Value of the Muthurajawela Wetland (3068ha),
Sri Lanka
Annual economic value (converted to 2003 US$)
Flood attenuation
5,033,800
Industrial wastewater treatment
1,682,841
Agricultural production
314,049
Support to downstream fisheries
207,361
Firewood
82,530
Fishing
64,904
Leisure and recreation
54,743
Domestic sewage treatment
44,790
Freshwater supplies for local
populations
39,191
Carbon appropriation
TOTAL
ECONOMIC VALUE
The Economic Value of the World’s Wetlands: WWF
8,087
7,532,297
RESTORATION
Dal Lake
Wular lake
Harike lake
Jheels in the vicinity of Haidergarh
Dahar and Souj jheel
Southern gulf of Kutch
Gulf of Khambhat
Dipor(deepar) beel
Loktak lake
Salt lake swamp
The Sundarbans
Chilka Lake
Kolleru lake
Estuaries of Karnataka Coast
Kaliveli Tank and Yedayanthittu Estuary
The Cochin backwater
Wet lands in the Andaman and Nicobar Island
Conservation
Conservation is management of resources to maximize
efficiency of use, minimize wastage and preservation for
future.
Resources such as lakes/wetlands vary over time and
space, their conservation requires reserves that can be
maintained and managed so as to ensure the supply of
their goods and services for future and do not reduce
options or impoverish future generations.
Restoration
The act of correcting an error or a fault or an evil. This is
the action to be taken to correct, to the possible extend,
the aberrations happened.
Regulation, Policy & Integration
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
Most Complex & Difficult to implement
technologies at field level
Water a State Subject, Centre Advisory Role
Departmental Ownership & Control
Privately Owned only a Few
Multiple Users/Beneficiaries
Policy Support Varies, State to State
Regulation, for declared protected sites only
For others Fragmentary in Nature
Cooperatives for Fishery, only in a few
Integration/Network with Water as Focus ?
Success story of Chilka restoration
largest lagoon along the east coast of India and a Ramsar site
Shelters a number of endangered species listed in the IUCN red
list of threatened species
Livelihood of more than 0.15 million fisher folk
Water quality deteriorated
Fish production declined
Salinity dropped
Sand bar blocked the connecting channel to the sea
Placed in the Montreux record in the year 1993 by Ramsar
bureau due to change in its ecological characters
Restoration
Desiltation of the lead channel and
an artificial mouth was opened on
23rd September 2000, which
reduced the length of the outflow
channel by 18 km
Sand bar formation
along the
mouth of Chilka
lagoon
Monitoring results indicated that
there is a marked improvement in
the lagoon ecosystem
Opening a new mouth
was a hard strategy,
which restored
Chilka environment
Improvement
Fishers’ annual income increased by more than Rs. 50,000 per
family
Improvement in fish landing in Chilka
Chilka is removed from the Montreux record in 2003
2005-06
2004-05
2003-04
2002-03
2001-02
1999-00
After
1998-99
1997-97
Before
2000-01
16000
14000
12000
10000
8000
6000
4000
2000
0
1996-97
Fish+Prawn+Crab landinf (M. T)
The fish landing improved substantially
OTHER LAKES
UNDER GOI NATIONAL LAKE CONSERVATION PLAN
MAASIVE EFFORTS HAVE BEEN MADE FOR OTHER
LAKES ALSO. SOME ARE :
DAL LAKE – MANY INITIATIVES TAKEN STILL IMPACT
IS NOT VISIBLE
BHOPAL LAKE – AFTER INTERVENTION SOME
IMPROVEMENT IS REPORTED.
NAINITAL LAKE – ACTION PLAN UNDER
IMPLEMENTATION HYPOLIMNION
AREATION BEING TESTED.
LOKTAK LAKE – MASSIVE EFFORT IMPROVEMENT TO
BE ON SUSTAINABLE BASIS.
Massive growth of Macrophytes
Dal Lake before and after dredging operations
Removal of illegal
"Radhs" (Floating
Gardens) from
Dal Lake
Mechanical and traditional method of deweeding
Dumping & transportation of weeds in progress
Save Lakes / wetlands
water for food – water for life.