conservation and restoration of lakes and wetlands … ·  · 2013-09-13conservation and...

Conservation and Restoration of Lakes and wetlands

K.K.Vass Central Inland Fisheries Research Institute,

Barrackpore,

Kolkatta

, India.

Structure

General statusConcernsWhy conserveRestoration

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

Lakes and 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 definitionAccording 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 transitionalzone between permanently wet and generally dry environments.

MAIN FEATURESLakes/Wetlands of all sizes and morphometric charactersBoth Open and ClosedFormed through natural and manmade processesMost of these have heavy component of macrophytesHave both onsite and offsite benefitsHave multi-user operationsLarge human settlements around themUrban 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 surfaceOnly 10% of world’s lakes are located in the tropics

Global view on water and fish productionGlobal view on water and fish productionWorld's water resources

Inland water2 %

Oceans98 %

Inland water

frozen 88 %

soil moisture0.20 %

ground12 %

atmosphere0.04 %

saline0.31 %

Other1 %

lakes0.38 %

rivers0.004 %

frozen groundlakessalinesoil moistureriversatmosphere

Tropical lakes0.04 %

Oceans Inland watersFish species 60 % 40 %Capture 80 % 9 %Aquaculture 5 % 6 %Total production 85 % 15 %

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. reservoirsCharacteristics Lakes Reservoirs

Nature natural man-madeGeological age old youngAging slow rapid (first few years)Formed by depressions river valleysShape regular dendriticShore development ratio low highMaximum depth near centre extreme (at the dam)Bottom sediments autochthonous allochthonousGradients wind-driven flow-drivenOutlet surface/none deep

Ratio watershed/lake area low highRetention time high lowCoupling with watershed less greatMorphometry U-shaped V-shapedLevel fluctuations less greatHydrodynamics more regular highly variableCause of pulses natural man-made drawdowns

Quantitative (relative) difference

Qualitative (absolute) difference

Assam

West Bengal

Bihar

Uttar Pradesh

Uttarakhand

Himachal

Jammu & Kashmir

North East States

Coastal States

Major wetland/lake resources in India

The biological base for productivity

Phyto-plankton

Bacteria Detritus Phyto-plankton

Bacteria Detritus

Fish FishA = CrustaceaB = Rotifera and Protozoa

A B BA

Temperate lakes Tropical lakes

Food webs are often shorter in the tropics:

RIVERSWETLANDS & FLOODPLAINSLAKES/LAGOONSESTUARIESRESERVOIRS

WATER RESOURCES

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 classificationMeasured 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.

CONCERNSRapidly 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.

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

Concerns contd…

Destructive Fishing & De-silting a lake

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

Causes for loss

0

5000

10000

15000

20000

25000

Wastewater(MLD) BOD(t/d) BOD reduction(t/d)

DomesticIndustrial

(63%)

(37%)

(32%)

(68%)

(66%)(34%)

Pollution Load from Domestic & Industrial Sources

Metal Contamination in Different Components

ComponentsMetal Levels (μg g-1)

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

• 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

Biomagnification of DDT in aquatic food chain (ppb)

Bivalve 950

Sediment 70Water

0.06Plankton

150

Gastropod220

Fish450

Organochlorine pesticides in fish of river Ganga

0

20

40

60

80

100

120

Res

idue

con

c. in

ppb

Residue (ppb) 17 23 45 74 33 100 26 74 90 16

L. dero L. dero C. mrigala R. rita R. rita C. garua R. rita A. aor R. rita A. gagora

Rishikesh Hardwar Farukhabad Kanauj Kanpur Varanasi Patna Farakka Barrackpore Haldia

River Total residue (ppt)

Permissible limit exceeded by

Ganga river system

17 - 80 4,4’-DDTaldrindieldrin

Sediment metals in Indian rivers (ppb)

0

20

40

60

80

100

120

Ganga Mahanadi Godavari Krishna Cauvery Narmada

ZnCu

Anthropogenic Activities Industrial Domestic Agriculture UrbanizationDischarges to Wetlands √ √ √ √

Non-point Source Pollution √ √ √ √

Air pollutants √ X X √

Toxic chemicals √ √ √ XDeposition of fills √ √ √ √Construction X √ √ √Crop production X X √ XSiltation √ √ √ √Changing nutrient levels √ √ √ XTourism/ recreational X X X √Physical modification √ √ √ √

Sectors contributing to modification of lakes/wetlands

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

WHY CONSERVE THESE WATERS ?

StakeholdersGoods & Services

FishersAgriculture FarmersWater ManagersLocal CommunityRecreationTransportEco-TourismJute Industry

Economic value of wetlandsWhen 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

Shortage in irrigation water 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 employmentin 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 co- operative societies in West Bengal and Assam

Wild Wild -- Fishing and PollutionFishing and Pollution

Fish Marketing

Man made floating islands, made of aquatic vegetation, inLoktak 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 qualityin several wetlands in West Bengal.

Jute cultivation bring additional income and firewood/thatching material for fishers’ housing

Catla catla

Labeo rohita

Cirrhinus mrigala

Three Indian major carps beingstocked in wetlands under culturebased fishery management

Major Fishes of food value

Anabas testudineus

Channa punctatus Channa marulis

Badis badis

Minor Fishes of food value

Ornamental fishes

Colisa lalia

Colisa sota

Devario devario

Chanda nama

Ornamental fishes

Puntius conchonius

Rasbora daniconius Rasbora rasbora

Tetradon cutcutia

State Area (ha) Existing Potential Gap%

increaseProjected Increase

West Bengal 42.5 9.56 53.15 43.59 455.96 4.6 foldBihar 40 4.80 30.00 25.20 525.00 5.3 foldAssam 100 12.00 95.00 83.00 691.67 6.9 foldUttar Pradesh 152 22.80 114.00 91.20 400.00 4 foldOther NE states 19.2 1.49 15.78 14.29 959.06 9.6 foldTotal 353.7 50.65 307.93 257.28 507.96 5 fold

Production (000 t)

Production enhancement methods

Production potential per unit area versus spatial scale of production units of thevarious methods used in lakes and reservoirs. Arrow indicates the perceivedincreased environmental impacts moving from natural harvest to intensiveculture. (Ranges of production are tentative)

Environmental impact

Sustainable Fishery DevelopmentSystem Analysis

Production Function EstimatesBiodiversity AssessmentIdentification of Interventions

Fishery EnhancementStock ManipulationPen-culture & Cage-culture

Awareness & ParticipationNetwork Formation

Economic Value of the Muthurajawela Wetland (3068ha),Sri Lanka

Annual economic value (converted to 2003 US$)

Flood attenuation 5,033,800Industrial wastewater treatment 1,682,841Agricultural production 314,049Support to downstream fisheries 207,361Firewood 82,530Fishing 64,904Leisure and recreation 54,743Domestic sewage treatment 44,790Freshwater supplies for local populations

39,191

Carbon appropriation 8,087TOTAL ECONOMIC VALUE 7,532,297

The Economic Value of the World’s Wetlands: WWF

RESTORATIONDal Lake

Wular lakeHarike 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

Most Complex & Difficult to implement technologies at field level Water a State Subject, Centre Advisory RoleDepartmental Ownership & ControlPrivately Owned only a FewMultiple Users/BeneficiariesPolicy Support Varies, State to StateRegulation, for declared protected sites onlyFor others Fragmentary in NatureCooperatives for Fishery, only in a fewIntegration/Network with Water as Focus ?

Success story of Chilka restorationlargest 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

Monitoring results indicated that there is a marked improvement in the lagoon ecosystem

Sand bar formation along themouth of Chilka lagoon

Opening a new mouth was a hard strategy, which restoredChilka environment

ImprovementFishers’ annual income increased by more than Rs. 50,000 per family

The fish landing improved substantially

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1997

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Fish

+Pra

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Cra

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Improvement in fish landing in Chilka

Before After

Chilka is removed from the Montreux record in 2003

OTHER LAKESUNDER 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.

Dal Lake before and after dredging operations

Massive growth of Macrophytes

Removal of illegal "Radhs" (Floating

Gardens) fromDal Lake

Mechanical and traditional method of deweeding

Dumping & transportation of weeds in progress

Save Lakes / wetlandswater for food – water for life.