|
Wetlands
& Biodiversity
The
environmental sector is an important water user; and one that often
finds itself at the bottom of the list of priorities when supplies
become scarce. One component of IWMI's Water, Health and Environment
research looks at how the needs of wetlands and other ecosystems
can coexist with parallel human and irrigation demands.
Water
maintains natural ecosystems, which sustain biodiversity, help to
regulate the hydrological cycle and bring value to people in the
form of goods and service derived from activities in these ecosystems.
It is increasingly being recognized that one of the costs of large-scale
irrigation is the draining of wetlands or reduced river flows that
starve wetlands of their water. In other cases the inflow of irrigation
drainage into wetlands changes water quality and water levels—negatively
impacting plant and animal life.
IWMI research in this area is working to scientifically document
the relationship between irrigation water management and the environment
(especially wetlands) in an integrated manner, focusing on practical
solutions to quantify and manage irrigation water flows that can
sustain ecosystems while obtaining optimum agricultural production.
IWMI
works with both irrigation and nature conservation groups; the aim
is to bridge the gap between these two sectors, which often are
in conflict.
 |
 |
|
Smakhtin, V.U.;
Piyankarage, S.C.; Stanzel, P; Boelee, E. 2004. Simulating
the hydrology of small coastal ecosystems in conditions of
limited data. Research Report 77, Colombo, Sri Lanka
Piyankarage
S C, Mallawatantri, A P, Matsuno Y and Pathiratne K A S. 2002.
Estimation of nitrogen and phosphorus fluxes to Embilikala
and Malala lagoons in southern Sri Lanka. pp. 9-20. In Janaka
Ratnasiri (ed.). Assessment of Material Fluxes to the Coastal
Zone in South Asia and their Impacts. Proceedings of the APN/START/LOICZ
South Asia Regional Workshop, Negombo, Sri Lanka. 08-11 December
2002. The Sri Lanka National Committee of IGBP, Colombo, Sri
Lanka. 2003.
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)
Available on-line in HTML and PDF formats.
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)
Available on-line in PDF format, 8,991KB; requires
Adobe
Acrobat Reader™.
To order the print version: send your request and postal address
to iwmi.publications@cgiar.org.
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)
Available on-line in PDF format, 10,925KB -
requires Adobe
Acrobat Reader™.
To order the print version: send your request and postal address
to iwmi.publications@cgiar.org
|
 |
-
Expansion without extinction: how can
biodiversity be preserved in irrigation systems?
Understanding the impact of irrigation
development on biodiversity and identifying potential
strategies for conservation. more
information>>
- Sustainable
management of wetlands in southern Africa for poverty
alleviation
Examining the long-term sustainability and productivity
of low-lying shallow groundwater aquifers in Zimbabwe,
Malawi and other Southern African countries. more
information>>
- Modeling
water allocation between wetlands and irrigated agriculture:
a case study from the Gediz Basin, Turkey
Identifying water allocation regimes that balance
the needs of wetlands and irrigated agriculture.
more information>>
- Hydrologic
modeling of the Mekong River Basin for environmental impact
studies
Developing a hydrologic modeling tool that can be
used to explore the impacts of water management decisions
on water levels and the consequent impacts on fish life
and other aquatic species. more
information>>
- Impacts
of irrigation water on coastal wetlands: a case study
from Sri Lanka
Determining how changes in water quality due to irrigation
drainage flows impact the presence of birds and other
species in downstream lagoons. more
information>>
|
 |
|
What
are the impacts of upstream irrigation on coastal wetlands?
How can these impacts be minimized?
Bundala
National Park, a Ramsar Convention wetland in Southern Sri
Lanka, hosts a vast population of wildlife, migratory birds,
and aquatic life. IWMI recently studied the interactions between
the wetland and the upstream irrigation project.
The research
showed that:
- Pesticides and fertilizers used by farmers in the irrigation
scheme flow into the lagoons along with irrigation drainage
water. Because of the elevated nitrogen and phosphate levels,
eutrophication is an emerging problem in the lagoons.
- The changing water levels affect birds and other wildlife.
And the inflow of drainage water has disturbed salinity
balances, resulting in fewer shrimp maturing in the lagoons.
Shrimpers periodically cut the sandbanks separating the
lagoons from the sea to achieve a direct increase in salinity.
Based
on these findings, the Irrigation Department of Sri Lanka
has introduced a rotational water supply. This minimizes water
losses to the sea and diminishes the impact of irrigation
drainage on coastal lagoons. Other options include: reducing
drainage flows by more closely matching the amount of irrigation
water supplied to crops' actual needs. Preliminary modeling
studies suggest that fertilizer applications could also be
reduced without affecting crop yields.
|
 |
|
The World
Resources Institute's Earth
Trends provides access to extensive databases, maps, country
profiles and feature articles on a number of topics linked
to wetlands and biodiversity.
|
|
|
|
How
can we determine the amount of water natural ecosystems
need?
What
are possible strategies for ensuring wetlands receive
the water they need, without decreasing the yields from
irrigated agriculture and poor farmer's incomes?
How
can developing countries meet the need for expanding
agricultural areas without sacrificing biodiversity?
How
can the damage to wetlands caused by flows from irrigated
areas be reduced?
How
do we value ecological goods and services?
|
|
![]() |
|
