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IWMI Projects on Wetlands & Biodiversity
Expansion without extinction: how can biodiversity be preserved in irrigation systems?
Project duration: 2001-2004
Objective: To identify potential strategies for biodiversity conservation in areas being developed for irrigated agriculture
Field research location: Uda Walawe Irrigation Extension Development Project, Ruhuna Basin (an IWMI Benchmark Basin), Southern Sri Lanka
Partners:
Background: The agricultural sector plays a major role in Sri Lanka's economy, and irrigation has received a high priority in development initiatives. While this has contributed to greater agricultural productivity and better livelihoods for rural people, the small (65,000 km2) island has lost vast areas of natural ecosystems, which in turn, has led to a qualitative and quantitative depletion of the country's flora and fauna.
The 15,000 ha Udawalawe Irrigation Extension Development Project in southern Sri Lanka provides a unique opportunity to carry out a long term scientific study on biodiversity change in relation to agricultural development, and thereby provide the means to develop strategies for biodiversity conservation in such development areas.
Project description: The conceptual framework underlying the project is that of "Ecoagriculture" which refers to land-use systems managed for both agricultural production and wild biodiversity conservation. The proposed 3-year project which will being done by IWMI in association with IUCN and the Mahaweli Authority of Sri Lanka, aims to monitor biodiversity changes from pre- to post development phases, monitor changes in the socioeconomic status of stakeholders, sensitize stakeholders (farmers and school children) to biodiversity conservation and sustainable use issues, and implement biodiversity conservation measures in the context of agricultural development. The predevelopment phase of the project is currently in progress.
Contact person: Felix P. Amerasinghe at f.amerasinghe@cgiar.org
Sustainable management of wetlands in southern Africa for poverty alleviation
Project duration: 2001 - 2006
Objective: To develop ecologically sound options for wetland-based livelihood strategies in southern Africa
Field research locations: Lesotho, Malawi, Mozambique, South Africa, Swaziland, Tanzania, Zambia, Zimbabwe
Partners:
Background: Seasonally waterlogged lowland wetlands (known as Dambos or Mbugas in southern Africa) are an important component of rural livelihoods. They cover at least 2 million ha. of which about 250,000 ha are under traditional irrigation in Zambia, Zimbabwe and Malawi alone. Less than 10% of the utilizable wetlands are currently in use, and this has prompted several rural development agencies to explore options for intensified and expanded use, while conserving the natural resource base. However, there is almost no scientific information on profitable agronomic measures and technological interventions for wetland cropping suitable for poor people.
Little is known of ways to improve other uses such as aquaculture. Institutional arrangements for land tenure and water rights are poorly understood, and insufficient for policy formulation and implementation. More importantly, productivity-enhancing measures may entail serious ecological risks in terms of the hydrology and biodiversity of these wetlands, which are at risk of both drying and flooding.
Project description: The proposed project aims to address this lack of scientific data in order to provide ecologically sound options for wetland-based livelihood strategies in southern Africa. An inventory of wetland resources in 8 countries will be made initially, followed by detailed hydrologic, agronomic, biophysical, biodiversity, socioeconomic, gender, legal and institution-related investigations at representative sites.
Contact person: Mutsa Masiyandima at m.masiyandima@cgiar.org
Hydrologic modeling of the Mekong River Basin for environmental impact studies
Project
duration:
2000-2001
Objective: To develop a hydrologic model that can be used to explore the impacts of water management decisions on levels in the Tonle Sap lake and the consequent impacts on aquatic resource production.
Field research location: Tonle Sap, Cambodia
Partners:
Background: The Mekong River (800,000 km2 basin) arises in Tibet and flows through China, Burma, Thailand, Laos and Cambodia before reaching the South China Sea in Vietnam. Riparian people, flora and fauna depend on the river's annual cycle of flood and drought. Wetlands along the river supply 50-80% of total protein intake for basin residents in the form of fish. Cambodia's Tonle Sap (Grand Lake) plays a vital role in the Mekong river system and Cambodia's economy, with fish harvests that can reach 100,000 tons per year. The development of the Mekong river basin and, in particular, the construction of dams on the mainstream will affect downstream water levels and flows, impacting on fisheries and on the environment.
Project Description: As part of a joint project with the International Center for Living Aquatic Resources Management (ICLARM) and the Mekong River Commission (MRC), IWMI applied the Semi-Distributed Land Use Runoff Process (SLURP) Hydrological Model to the Mekong basin. SLURP uses a digital elevation model to define the basin, sub-basins and river network, a digital land cover map to define land use, and daily climate data to simulate the full hydrological cycle for each element of a subbasin/land cover matrix, and routes the runoff to the nearest stream and downstream through the basin.
The model was applied for the period 1 January 1994 to 31 December 1998. The simulated levels of Cambodia's Tonle Sap lake were converted to time series of flooded area for the land cover types around the lake. These results may be used to evaluate fish productivity and irrigation productivity as well as water allocation issues and climate change impacts. learn more about IWMI's work in Cambodia...
Publications:
Available on-line:
KITE, G. 2000. Developing
a hydrological model for the Mekong Basin: Impacts of basin development
on fisheries productivity. Colombo, Sri Lanka: IWMI. v, 141p. (IWMI
working paper 2)
Follow link to access on-line: PDF format 10,925KB - requires
Adobe
Acrobat Reader™. To order the print
version: send your request and postal address to iwmi.publications@cgiar.org
Contact person:
Hammond Murray-Rust at h.murray-rust@cgiar.org
Impacts of irrigation water on coastal wetlands: case study on the RAMSAR wetlands in southern Sri Lanka
Project
duration: 1999
- 2000
Objective: To determine how changes in water quality due to irrigation drainage flows impact the presence of birds and other species in downstream lagoons
Field research location: Bundala National Park & Kirindi Oya Irrigation and Settlement Project, Ruhuna Basin (an IWMI Benchmark Basin), southern Sri Lanka
Partners:
Background: The Bundala National Park (BNP) in southern Sri Lanka has within its area five RAMSAR-designated brackish water lagoons that constitute important wetlands for migratory and resident water birds. Two of the lagoons (Embilikala and Malala) have been severely affected by outflow irrigation water from the right bank of the Kirindi Oya Irrigation and Settlement Project (KOISP), resulting in their conversion virtually to freshwater lakes.
Project description: As part of an ongoing multidisciplinary study of the impacts of the KOISP on the BNP lagoons, IWMI and partners (IUCN, University of Peradeniya) carried out a short-term reconnaissance of the water bird fauna during the October 1999 - January 2000 migratory season, together with surveys of selected flora, fauna and water quality at the bird-feeding sites in three lagoons.
The Bundala lagoon (unaffected by irrigation water) had markedly higher EC, total-N, ammonia-N and TDS than Embilikala and Malala lagoons. Phosphate and total-N levels were indicative of eutrophication in all three lagoons. There were no significant differences in plant biomass, but plant species, zooplanktons and mollusks were distributed differentially in the three lagoons.
Fishermen's catches in the lagoons were dominated by Tilapia (even in Bundala lagoon), although brackish water finfish species were still present at Malala and Embilikala. Shrimps were scarce until an influx of sea water into Malala (via a breached sand bar) brought in planktonic larvae which matured and were harvested 2 months later. Only brine shrimps were observed in the Bundala lagoon. More than 60 species of water birds were recorded at the three lagoons.
Water level was a factor that significantly affected bird utilization of the lagoons. Irrigation water has led to the dilution of Embilikala and Malala lagoons, and the consequent invasion of more freshwater adapted flora and fauna. Studies aimed at modeling the quantity and frequency of irrigation water inflows so as to maintain the essentially brackish nature of these lagoons are planned.
Publications:
View complete listing of reports, books and journal articles
Donors: This project received funding from the Council of Agriculture and Private Irrigation Associations of Taiwan.
Contact person:
Felix Amerasinghe at f.amerasinghe@cgiar.org
Modeling water allocation between wetlands and irrigated agriculture, Turkey
Project duration: 1998-1999
Objective: To find ways of managing water so that the Kus Cenneti wetland receives enough water, without reducing the yields from irrigated farming.
Field research location: Kus Cenneti wetland, Gediz basin, Turkey
Partners:
- General Directorate of Rural Services, Agro-hydrology Research and Training Center, Turkey
- State Hydraulic Works (DSI), Turkey
Background: The Kus Cenneti is a RAMSAR wetland in the Gediz River Delta in Turkey, and an important habitat for threatened bird species such as the Dalmatian Pelican and Black Stork. The Kus Cenneti is threatened by water shortages and poor water quality resulting from damming and water abstraction for irrigation. Decreases in the extent of freshwater area and the area covered by reed beds have drastically reduced the feeding, breeding and sheltering possibilities for water birds in the wetland.
Project description: The Semi-Distributed Land Use Runoff Process (SLURP) Hydrological Model was used to study the ability of the Gediz basin to fulfill two important requirements for the survival of the wetland: a constant water level and a constant salt concentration (salt accumulation is lethal to freshwater reed beds which are the main breeding and sheltering place for birds), and the effects of this extra water withdrawal on irrigated agriculture in the basin.
The simulations showed that the Kus Cenneti water demand resulted in conflict with agriculture during irrigation seasons when there was insufficient water to satisfy both users. The deliverable supply to the wetland depended on the way in which water was allocated by water managers.
Three management options were evaluated in which water was diverted from all irrigation systems, varying the timing of water supply to the wetland and varying the timing of canal closure in the irrigation systems. The management options did not differ significantly in yield loss, because in all three options the same amount of water was diverted to the wetland, but they showed that even a high Kus Cenneti water demand did not influence crop yields to a great extent. The management alternative in which each canal supply is reduced by a few percent is recommended for dry years. For wet years, direct supply of the Kus Cenneti from the main reservoir is recommended.
Publications:
Available on-line:
KITE, G., P. DROOGERS,
H. MURRAY-RUST, and K. DE VOOGT. 2001. Modeling
scenarios for water allocation in the Gediz Basin, Turkey. Colombo,
Sri Lanka: IWMI. v, 29p. (IWMI research report 50)
Follow link to access on-line version. To order the print
version: send your request and postal address to iwmi.publications@cgiar.org.
DE VOOGT, K., G. KITE, P. DROOGERS, and H. MURRAY-RUST. 2000. Modeling water allocation between wetlands and irrigated agriculture: Case study of the Gediz Basin, Turkey. Colombo, Sri Lanka: IWMI. xi, 51p. (IWMI working paper 1)
View complete listing of reports, books and journal articles
Donors: This project was partially funded by the Government of Turkey and the World Bank-assisted Turkish Agricultural Research Plan (TARP)
Contact person: Peter Droogers at p.droogers@cgiar.org.
last updated:
4, September 2001
On this page:
Preserving
biodiversity in irrigation systems
Sustainable
management of wetlands for poverty alleviation
Modeling
water allocation between wetlands & agriculture
Modeling
for environmental impact studies
Impacts
of irrigation water on coastal wetlands