Specific research activities will
be focused on a series of case study basins from Europe, Africa and
South America. The following river basins and their corresponding
freshwater floodplain wetlands have been selected as case study and
twinning sites under the WETwin project:
Niger River Basin: Inner Niger
(Bakary Kone - mail: malipin - AT - afribone.net.ml)
Location of the Inner Niger Delta in the Niger River basin
The Inner Niger Delta (IND) a large
inland flood plain of 30 000 km?, is one of the four major hydrologically
distinct components of the Niger Basin. It has international importance
for biodiversity and forms a vital part of a regional ecological network,
with 3 to 4 million resident or migratory water birds from almost
all parts of the African-Eurasian Flyway.
The Inner Niger Delta (photo: L.
The IND is also critically important
for the livelihood support of one million people that depend on the
Delta resources and ecosystem. However three-quarters of them live
below the poverty level and the region has the lowest social indicators
in Mali. Regionally the low level of development and advanced state
of degradation of natural resources, as a result of climatic disturbances,
human pressure and upstream development, exposes the Delta's population
to acute food insecurity. This jeopardizes the balance of the ecosystem
in the area as people over-exploit its resource base. Furthermore
the IND's location downstream of the Upper Niger means that it is
subject to development decisions further upstream; therefore the status
of the IND is integrally linked to the effects of water resource management,
agriculture and industry.
Fishing in the Inner Niger Delta
(photo: L. Zwarts)
between fish yield and flood conditions illustrating the strong
of ecosystem services on hydrological conditions in the IND
Water supply in the IND is largely
directly from the river and waste disposal is often discharged directly
into the river. Although pollutant concentrations in the Niger are
low, point source gives rise to some highly localized effects; measured
data suggest a strong link between these sources and human health.
Among diseases encountered in the basin, 80% are linked to drinking
water supply and sanitation conditions. The main pollution sources
that contribute to these problems are as follows:
a) Human waste disposal:
Many medium to large size settlements in and on the edge of the IND
have basic sanitary systems that result in solid and liquid domestic
wastes and sewerage water being discharged directly into the Delta.
Mopti town is one such settlement where it is estimated that 15000
m?/day domestic wastes are discharged;
Settlement in the Inner Niger Delta
(photo: L. Zwarts)
b) Industrial waste disposal.
These wastes are generally dumped in the Niger River and especially
in the Inner Niger Delta, resulting in degraded water quality in some
localities which negatively impacts ecosystem health. This creates
the conditions where human health can suffer due to contamination
of water supply, promotion of conditions for water-borne disease and
effects on the population and quality of fish that used for human
c) Irrigation wastewater disposal. The discharge of irrigation
water into the IND can create significant water quality problems in
localized areas. These waters carry the fertilizers and pesticides
applied to crops which become more concentrated as the water passes
through the agricultural system losing water through evaporation.
For instance in Office du Niger (Macina) it is recorded that in 1994
6000 and 4000 t of urea and phosphates were used to fertilize 47000
ha of rice fields. As result eutrophication phenomena have been observed
with proliferation of invasive weeds (Pistia stratiotes, Eichornia
crassipes and Salivinia molesta).
d) Irrigation water management. The irrigation channels of
the Office du Niger are inefficient resulting in widespread leakage
and ponding of water. For instance nowadays 25 000 m? water is needed
to irrigate 1 ha of rice instead of 15 000 m? in the past. Associated
with this are outbreaks of diseases such as bilharzia, malaria etc.
Rice cultivation in the Inner Niger
Delta (photo: B. Kone)
White Nile River Basin: the wetlands of Masaka and Mbale
(Rose Kaggwa - mail: rose.kaggwa - AT - nwsc.co.ug)
Location of the Masaka (NakayibaNabajjuzi)
and Mbale (Namatala) catchment - wetland systems in Uganda
Specific research activities under
WETwin for the Upper White Nile River Basin will be conducted on two
sites: the Namatala and NakayibaNabajjuzi wetland system
in Eastern and Central Uganda. Both are near major towns (Mbale and
Masaka, respectively) and play an important role in processing wastewater
and providing drinking water for the human population. Each one of
the towns (both around 70.000 inhabitants) has small laboratories
being run at the water treatment plants of the National Water and
Sewerage Corporation (NWSC).
The NakayibaNabajjuzi system
is made up of both permanent and seasonal wetland types dominated
by papyrus. Crested cranes, white egrets and ibises are some of the
birds that frequent it. It has important social and cultural values
as it is a source of raw material for crafts and mulching, domestic
and livestock water.
The NakayibaNabajjuzi wetland (photo:
Its hydrological and physical values
are: effluent/sewerage purification, storm water storage, water table
discharge/recharge for the surrounding wells and sediment trapping.
Before 2005, the wetland was threatened by changes in land-use and
major development projects (cultivation in the core wetland area,
settlements, soil erosion from deforestation in the river basin).
After recognising its critical vital functions, WD together with other
stakeholders embarked on a restoration initiative for the Nakayiba
wetland. All destructive activities were ceased in order to protect
the wetland, mainly as a source of water and for sewerage/wastewater
purification and storm water storage. Wetlands Division and Masaka
District Local Government (MDLG) are preparing to develop a Community
Based Wetland Management Plan (CBWMP), for which important input can
be provided trough WETwin.
Tannery treated effluent discharges
into the Nabajuzzi wetland (photo: P. Isagara)
The Namatala system is located
south of Mbale Municipality and composed of tributary wetlands of
Nashibiso and Masanda, and joining a flood plain with a tributary
wetland north of Mbale. Namatala wetland is a very big system that
transcends across seven districts. It drains into the Mpologoma wetland
system. Mbale can be taken as a reference for this wetland system.
A management plan was developed but has not been fully implemented
yet. Important threats exist from changes in land use and major development
projects: soil erosion, sewage from Mbale and industrial wastewaters.
An additional important contribution of the project can consist of
the evaluation of sustainability of proposed management options under
changing environmental conditions (climate change).
Rice paddies in the Namatala wetland
(photo: R. Kaggwa)
Olifants River Basin: Ga-Mampa
(Mutsa Masiyandima - mail: M.MASIYANDIMA - AT - CGIAR.ORG)
Location of the Ga-Mampa wetland
in the Limpopo river basin
The wetland study site on which
the main focus will fall within the Olifants River Basin is the Ga-Mampa
wetland of the Mohlapetsi River catchment. It is located between
24° 05' - 24° 20' S and 30° 00' - 30° 25' E in the
Limpopo province of South Africa. The Mohlapetsi River originates
in the Wolkberg Mountains and is one of the tributaries of the Olifants
River. The wetland covers approximately 1 km2 in a total area of 490
km2 at the confluence with the Olifants River.
Although only a small tributary, the Mohlapetsi is perceived as important
for the hydrology and hence water resources of the Olifants River.
The general perception is that this tributary makes a significant
contribution to the flow of the lower Olifants, particularly in the
dry season. The area falls within the Lepele Nkumpi Municipality,
Capricorn District of the Limpopo Province, part of the former Homeland
of Lebowa. The majority of people living there are of the Pedi tribe.
The Ga-Mampa wetland (photo: M.
The catchment surrounding the wetland
comprises relatively natural grassland vegetation, contained within
a National Reserve. It is predominantly rural, with a low population
density. The total population in the immediate area surrounding the
wetland is estimated at about 1700 people. All villages are located
and agricultural activities occur in close proximity to the valley
bottom and in the wetland. The main sources of livelihoods in the
valley come from smallholder agriculture, both in irrigation scheme
and in the wetland, and social transfers from the government. In addition
to agriculture, the wetland is used for livestock grazing, collection
of raw material for craft and building and collection of edible plants.
Water is abstracted from the wetland for domestic and irrigation use.
Grazing cattle in the Ga-Mampa
wetland (photo: S. Morardet)
The main pressures on the wetland
arise from its increasing use for agriculture (in the past 10 years
half of the original natural wetland area has been encroached by agricultural
plots). This is related to increasing population by limited land availability,
which is even worsened by the degradation of neighbouring small-scale
irrigation schemes. This situation has led to potential tensions between
the local community and external stakeholders (sector government departments,
local government and environmental lobbyists).
Drainage canal in Ga-Mampa leading
to the desiccation of the wetland (photo: M. Masiyandima)
Key impacts on the ecosystem include:
Guayas River Basin: Abras de Mantequilla
(Maria del Pilar Cornejo de Grunauer - mail: pcornejo - AT - espol.edu.ec)
Location of the Abras de Mantequilla in the Guayas river basin
The Abras de Mantequilla drains
into the Rio Chojampe (Rio Nuevo), a tributary of the Rio Vinces which
empties into the Río Babahoyo. These form all part of the Guayas
River Basin. The Guayas River flows southward to the Gulf of Guayaquil
and constitutes the most important of the drainage systems in the
Costa Internal. Abras de Mantequilla is the only RAMSAR wetland site
in this 40.000 km2 big Ecuadorian river basin.
The Abras de Mantequilla wetlands
are formed by the natural damming of the San Francisco de Chojampe
and Mapancillo swamps. Water depth, on average 4.5m, increases during
the rainy season when floods cause it to overflow to the Rio Nuevo
through the Camito swamp. The main lake of the wetlands (Abra Central
- El Aromo) is formed in a slight depression and has created branches
among the low elevation without a specific outlet. Lake surfaces area
drops considerably during the dry season. The wetland is 7.3km east
of the City of Vinces (pop. 40.000).
Abras de Mantequilla wetland during
the dry season (photo: P. Cornejo)
Human use of wetlands and surrounding
areas correspond to: fishing, agriculture and grazing. Water is used
for growing rice, maize and for commercial and subsistence fishing.
Large landowners obtain food and income from livestock. More water
from the wetland is used during the winter than during the summer,
when wells are used for domestic water supply. During the rainy season,
local inhabitants take water for human consumption directly from the
lake. All waste water of the 80 communities in the wetland however
is discharged directly into the wetland, without any form of treatment.
Abras de Mantequilla wetland during
the wet season (photo: M. Arias)
Over-exploitation of aquatic resources
and small-mesh fishing have led to a decreased availability of native
species with high commercial and nutritional value for the local inhabitants.
The introduction of the exotic Tilapia is having an additional, drastic
impact on the populations of native species. The drainage basin surrounding
the lake has been severely degraded. Currently only some remnants
of the initially extensive native forest cover remain. Water pollution
due to pesticide in runoff is a potential threat to the area, however,
currently no studies have been made to evaluate this situation.
Settlements in the Abras de Mantequilla
(photo: M. Arias)
The Ministry of Environment (stakeholder
with in-kind contribution) and the Commission for the Development
of the Guayas River Basin CEDEGE (subcontractor) have been trying
to improve water quality and to preserve the wetland from pollution.
The population is using the services of the wetland. Support on wetland
management however is required for better performance. CEDEGE, furthermore,
has been facing public unrest over the planned implementation of a
dam elsewhere in the Basin. As a consequence, they now want to pursue
ways to improve public participation. By means of WETwin, opportunities
may be created to put the attention on the special role that the Abras
de Mantequilla wetlands fulfil.
River Basin: the Spreewald Wetland
(Fred Hattermann - mail: hattermann - AT - pik-potsdam.de)
Location of the Spreewald wetland
within the Spree river basin
The Spreewald wetland covers an
area of 750 km2. It is a Biosphere Reserve, located 100 km South-East
of Berlin, in the Lausitz Region of Germany. The landscape of the
area was shaped during the ice-age, and the major ecosystem type corresponds
to temperate broadleaf forests and woodlands. Alder forests on wetlands
and pine forests on sandy dry areas are characteristic for the region;
however, also grasslands and cropland can be found, where drainage
systems have been implemented.
The Spreewald wetland (photo: F.
The Spreewald is known for its
traditional irrigation system consisting of 1300 km of small channels
(called 'Fliesse') within an area of 48400 ha which are still in use.
Approximately 50000 people live within this biosphere reserve. Many
of them are descendants of the first settlers in the Spreewald region,
the Slavic tribes of the Sorb/Wends. Until today, they have preserved
their traditional language, customs and clothing. People living in
the area mostly depend on tourism. However, also agriculture, forestry
and fishery are important sources of income.
Tourism in the Spreewald (photo:
The Spreewald wetland is part of
the Spree river basin. The Spree connects the river network of Berlin
to the Elbe-Havel river basin. The critical inflow to Berlin, needed
to guarantee healthy water conditions, is 8 m3s-1. However, in the
summers of 2003 and 2006, the inflow was significantly lower and the
river flew backwards due to the inflow of treated wastewater in Berlin,
causing problematic water quality conditions in the river. The projections
into the future show that this situation may happen much more often
over the next decades. Climate change and mining activities in the
Lausitz lignite field, located next to the Biosphere Reserve (one
of the largest open mining area in Europe), constitute major threats
for both water quality and ecological status. Over the last decades,
a trend towards lower precipitation -especially in summer- could be
observed, leading to dryer conditions. This effect could be compensated
in the past by water influx from the open mining pits. However, the
mining activities have slowed down and therefore the amount of water
withdrawal from the pits decreases. This, in combination with the
climate change, may cause that an acceptable wetland status cannot
be guaranteed, unless a more adaptive approach to integrated water
resources management -which takes into account the relation between
the wetland and its hosting river basin- is applied.
Desiccation problems in the Spreewald
wetland (photo: M. Zebisch)
The Spreewald wetland has been
selected in this project because it combines different features which
can stimulate the discussion and exchange of knowledge about the combined
impacts of human water regulation and climate change. The question
is which adaptation measures can be applied to save the wetland ecosystem
and guarantee the provision of sufficient water of appropriate quality
to the local population. At present, the Biosphere Reserve Agency
is trying to apply a new management concept, which integrates the
relevant stakeholders, ecology being one of them. The project activities
on the wetland will contribute to integrated water management solutions,
which shall be identified in WP7 and quantified in WP8, but also to
allocate "lessons learned" from the past about the problematic
results of wetland degradation, as a consequence of the lack of integration
Danube River Basin: Lobau (Austria)
and Gemenc (Hungary) floodplains
Location of the Lobau and Gemenc
floodplains within the Danube river basin
Lobau Floodplain (Austria)
(Thomas Hein - mail: thomas.hein - AT - boku.ac.at)
Draining over 96% of Austria's
territory, the Austrian Danube River Basin is home to 7.7 million
people. Along its flow through Austria, the Danube has formed extensive
fluvial landscapes. A remaining of these are contained in the 36km
National Park stretch, starting downstream of Vienna. Although the
total extension of these areas has been drastically reduced due to
conversion to arable land and flood protection, a unique and extremely
species-rich floodplain area still exists. The river waters flood
this area and determine the natural rhythm and high dynamics of the
riparian wetlands. The highs and lows of water levels (which can vary
by as much as 7 metres) show the extreme range of conditions to which
the riparian wetlands are subjected. These varying conditions lead
to a diversity of habitats and species.
Satellite image of the Lobau floopldain
The Lobau is a large floodplain
right at the eastern border of the city of Vienna, located within
the National Park. The importance of the Danube stretch downstream
of Vienna has been described in numerous papers. The Lobau was designated
as a UNESCO Men and Biosphere Reserve in 1977, a RAMSAR site in 1982,
is an integral part of the "Alluvial Zone National Park"
since 1996, and was designated a Natura 2000 area by the EU. It is
dominated by a former river channel that was severed upstream from
the main channel after the main regulation of the Danube in the 19th
century. Lateral embankments along the main river channel severely
altered the geomorphic and hydrologic dynamics and impeded the natural
sequence of erosion and sedimentation. During the last decades vertical
erosion in the main river bed (incision), in concert with ongoing
aggradation in the floodplain, have further decoupled the wetland
from the river, both hydrologically and ecologically.
The Lobau floodplain (photo: V.
Today, the Lobau represents a groundwater-fed
and back-flooded floodplain lake system, where sedimentation and terrestrialisation
processes prevail. Specific soil conditions and deficits in hydrologic
dynamics favour the -atypical- establishment of rare elements of dry
meadows in the former floodplain. Above mean water level (~1900m3s-1)
the fragmented floodplain water bodies become connected to the main
channel, still only at the downstream end.
The Lobau plays a central role
in the catchment water balance. It retains floodwaters, recharges
the groundwater, and provides further socio-economic values (e.g.
drinking water supply, recreation). Because of its proximity to Vienna,
the Lobau has always been of focal interest to flood protection plans
for Vienna and Lower Austria. In addition, the Lobau serves as an
important drinking water reservoir (riverbank-filtration) for the
City of Vienna. In certain situations, like drought or maintenance
activities, the floodplain can provide drinking water to about 25%
of Vienna's inhabitants.
Despite its protected status, it
is still affected by multiple human impacts. Weirs, although partly
already lowered and broadened, divide the side-arm into several basins
with different connection pattern to the Danube main channel. The
effects of intensive forestry, fishing and agriculture in the area
contributed to these changes and increased the effects of invasive
species. Industry, agriculture and the runoff from the city of Vienna
have increased the nutrient input into the floodplain. Still, the
high self-purification capacities of riverbank filtration allow the
city of Vienna to use the Lobau area for drinking water supply.
The Lobau floodplain will be used
in this project as a case study of a highly urbanized floodplain.
As protected by different national, European and international regulations,
the Lobau has been continuously investigated and, therefore, is a
data-rich case study. Because of this linking with other international
organizations and goals, the Lobau can become integrated in the future
river basin management plan. The existing knowledge from the stakeholders
of the Lobau and the ongoing research project (Optima Lobau under
the Austrian research program "ProVision") will be used
for information exchange and expertise within the framework of WETwin,
in order to harmonize the projects' developments towards balancing
the partly competing ecologic and socio-economic requirements for
sustainable wetlands and water resources management.
Gemenc Floodplain (Hungary)
(István Zsuffa - mail: istvan.zsuffa - AT - vituki.hu)
The Báta sub-system of the Gemenc Floodplain
The Gemenc wetland can be found
along the lower reach of the Hungarian Danube. It is a sub-region
of the Danube-Dráva National Park. The Gemenc is a 4-5 km wide
and 30 km long floodplain on the right bank of the Danube bordered
by a flood control dike from the West. This area is covered mainly
by alluvial forests, which are fragmented by different water bodies.
The types of these water bodies cover the full range of functional
sets: eupotamon, parapotamon, plesiopotamon and paleopotamon water
bodies are all present in this floodplain.
The Gemenc floodplain (photo: K.
The ecological importance of the
Gemenc is very high as it hosts habitats for several endangered species
such as the Black Stork, the White-tailed Eagle as well as several
other aquatic and terrestrial species. The Gemenc is a true core area
within the Danubian ecological network: species find refuge here,
as well as excellent conditions for growth and reproduction thanks
to the area's high biological productivity. The floodplain is an especially
important nesting, feeding and resting habitat for migratory birds
such as the Black Stork. Important ecological links between the Gemenc
and wetlands in Africa exist, as a significant percentage of the Gemenc
Black Storks choose African wetlands as wintering habitat (e.g. the
Inner Niger Delta and the wetlands of the Upper White Nile Basin).
Black Stork in the Gemenc floodplain
(photo: B. Kalocsa)
During the past decades several
ecological problems have been encountered on the floodplain. The most
important one is desiccation, which is the combined consequence of
sedimentation and river bed incision processes. In addition, the flood
regime of the river has also changed: nowadays the intensity of the
rise and fall of flood pulses are much higher, and the duration of
floods are much shorter than in the pre-regulation times. This has
contributed a lot to the destruction of habitats for aquatic fauna.
Erosion and sedimentation processes
in the Gemenc floodplain (Tamás & Kalocsa, 2002)
As a result, the once rich and
diverse alluvial ecosystems of the Gemenc are now gradually changing
to poor, dry systems. In addition, intensive land use activities -first
of all forestry but also recreation- bring additional pressures on
the nature by means of destruction and disturbances. During the past
years, forestry methods have been changed for the benefit of nature,
nevertheless clear-cutting is still applied at many locations on the
floodplain, which is a significant contradiction in respect of the
national park status of the area.
Wood production in the Gemenc floodplain
(photo: Beni Baba)
Several plans have already been
devised for the ecological rehabilitation of the Gemenc floodplain.
One of these plans proposes flow control interventions with the aim
of improving the water regime, which is the key driver for floodplain
functions. Because of the conflicting multi-objective nature of the
problem (ecology vs. land uses), a decision support system has been
set up in order to support decision makers at arriving to best compromise
solutions for the revitalization of the floodplain. Restoration plans
are being developed by the Reduction of Nutrient Discharges Project
(GEF # TF 051 289) too. Besides ecological restoration, this project
put emphasize also on making use of the floodplain's nutrient reduction
potential in order to reduce nutrient loads to the Danube and to the
Black Sea. Technical and management solutions are being developed
for improving the nutrient reduction potential of the floodplain.
It can thus be concluded that the
experiences of past and ongoing projects related to the Gemenc do
have the potential to contribute to achieving the objectives of the