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(Click to enlarge)
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The Mesopotamian Marshlands: From wetlands to dry lands
The Mesopotamian Marshlands in the Tigris and Euphrates river basins
were devastated by damming and river channelisation during the late
1980s. Satellite images taken in 1973-76 revealed that the wetlands
were more or less intact. By 2000, however, most of the dense marsh
vegetation had been replaced by vegetation on moist-to-dry soil.
- Massive drainage works in southern Iraq in the late 1980s and
early 1990s, together with major upstream damming, caused the
loss of more than 9 000 km2 of wetlands and lakes
from the vast and ecologically vital marshlands.
- Only minor and fragmented parcels remain today of the marshlands,
which once covered an area of 15 000-20 000 km2.
At least 7 600 km2 of primary wetlands (excluding seasonal
and temporary flooded areas) were lost between 1973 and 2000,
with most of the change occurring between 1991 and 1995.
- The central and Al Hammar marshlands have been completely destroyed,
with 97% and 94% of their respective cover transformed into bare
land and salt crusts. Less than a third of the transboundary Hawr
Al Hawizeh/Al Azim marshland remains today.
- The water filtering role of the marshland has ceased and the
Saddam River discharges polluted agricultural drainage directly
into the Shatt-al-Basrah Canal, before emptying into the Gulf
at Umm Qasr via the Khawr al-Zubair. The seawater around Warbah
Island on the Iraq-Kuwait border has become less saline and more
polluted, with potentially harmful impacts on local fish resources
(Partow, 2001).
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- The entire Marsh Arab community has suffered serious social
and economic upheaval as a result of the marshlands' destruction.
About 40 000 Marsh Arabs were forced to flee to southwest
Iran because of this natural disaster, combined with the 1991-93
armed conflicts (AMAR, 2001; UNCHR, 1996).
- The impact on marsh wildlife and biodiversity has been catastrophic,
with the probable extinction of the endemic smooth-coated otter,
and the disappearance of the African Darter and the Sacred Ibis
from the Middle East. A further 66 bird species existing in the
marshlands in internationally significant numbers are now at risk.
A wide range of migratory aquatic species have been affected -
including the penaied shrimp, which migrates between the Arabian
Gulf and nursery grounds in the marshlands - with serious economic
consequences for coastal fisheries in the northern Gulf.
- The disappearance of the marshlands will doubtless have a significant
impact on the regional micro-climate, with an anticipated reduced
cooling effect from the wetlands and lakes (Partow, 2001).
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| A 'Win - Win' Solution: Using
Constructed Wetlands for Wastewater Treatment, Habitat Creation and
Food Production |
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Constructed Wetlands (CWs) use the natural processes involving
wetland vegetation, soils and associated microorganisms to assist
in treating wastewater. They are designed to take advantage of many
of the processes that occur in natural wetlands, in a more controlled
environment.
Constructed Wetlands fall into two general categories: Subsurface
Flow Systems (SFS) and Freewater Surface Systems (FSS). SFS systems
are applied to improve water quality, while FSS systems maximise
wetland habitat values and reuse opportunities, while also improving
water quality.
Benefits of using Constructed Wetlands:
- Constructed Wetlands are an effective, environmentally friendly
means of treating liquid and solid waste. Research in France in
the 1980s, for example, indicated that Reed Bed Filters (SFS)
designed to treat waste from 100-250 people were highly effective
in improving water quality.
- CWs are effective at reducing loads of BOD/COD, nitrogen, phosphorus
and suspended solids by up to 98%. However, despite the suitability
of climate in developing countries, the spread of wetlands in
such areas has been "depressingly slow" (Denny et al., 1997).
- In recent years, there has been a tendency to construct more
SFS-type wetlands, which are believed to be more effective in
treating wastes.
- Despite current usage patterns, tropical and subtropical climates
hold the greatest potential for wetland use. Cold climates cause
problems because of both icing and thaw. The annual production
of papyrus in tropical conditions, for example, can exceed 100
tonnes per ha per year. The foliage can be sustainably cropped,
while the papyrus stems can be used for matting and thatching
roofs. Water that has passed through the wetland can be used to
irrigate crops and/or introduced to fishponds. In this final stage,
the remaining nitrates and phosphates stimulate the growth of
phytoplankton - the favourite food of Tilapia, a freshwater food
fish becoming increasingly popular in Europe.
- CWs require little maintenance, and remain effective after more
than 10 years of use.
- CWs could bring major economic benefits to developing countries
through the provision of biomass and aquaculture. Such wetland
systems can yield a significant profit for local communities,
and might be a powerful tool for breaking the poverty cycle.
- In developed countries, CWs can provide a valuable habitat for
wildlife and a natural tourist attraction. Slimbridge in the UK
has become a popular venue for viewing birds, amphibians such
as frogs, newts and toads, and insects such as dragonflies. Its
wetlands are also used to treat all liquid waste produced on-site
(up to 4 000 m3 per day).
Source: Fujita Research, 1998.
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Wetlands remain a grossly underestimated asset in many parts
of the world. Because of their erroneous reputation as unproductive
ecosystems or hazardous places, many governments still encourage
the conversion of wetlands to more productive land uses. In recent
years, however, people are coming to understand and appreciate the
multitude of vital environmental functions that wetlands perform.
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The value of these environmental services to humankind
is immense. Costanza et al. (1998) estimated the global value of wetlands
at nearly US $5 trillion a year, based on their ecosystem functions
as flood regulators, waste treatment plants, wildlife habitats, and
areas of fisheries production and recreation. Another estimate put
the value of one hectare of wetland at US $15 000 (Holmes, 1997).
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