Journal of Environmental Management 111 (2012) 159e172
Contents lists available at SciVerse ScienceDirect
Journal of Environmental Management
journal homepage: www.elsevier.com/locate/jenvman
Quantifying ecosystem service trade-offs: The case of an urban floodplain
in Vienna, Austria
Samai Sanon a, *, Thomas Hein b, c,1, Wim Douven a, 2, Peter Winkler b, c, 3
a
UNESCO-IHE Institute for Water Education, Westvest 7, PO Box 3015, 2611 AX Delft, The Netherlands
University of Natural Resources and Life Sciences, BOKU Vienna, Institute of Hydrobiology and Aquatic Ecosystem Management, Gregor Mendel Straße 33, Max Emanuelstr. 17,
A-1180 Vienna, Austria
c
WasserCluster Lunz GmbH, Inter-University Centre for Aquatic Ecosystem Research, Dr. Carl Kupelwieser Promenade 5, A-3293 Lunz am See, Austria
b
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 23 September 2011
Received in revised form
5 June 2012
Accepted 13 June 2012
Available online 11 August 2012
Wetland ecosystems provide multiple functions and services for the well-being of humans. In urban
environments, planning and decision making about wetland restoration inevitably involves conflicting
objectives, trade-offs, uncertainties and conflicting value judgments. This study applied trade-off and
multi criteria decision analysis to analyze and quantify the explicit trade-offs between the stakeholder’s
objectives related to management options for the restoration of an urban floodplain, the Lobau, in
Vienna, Austria. The Lobau has been disconnected from the main channel of the Danube River through
flood protection schemes 130 years ago that have reduced the hydraulic exchange processes. Urban
expansion has also changed the adjacent areas and led to increased numbers of visitors, which hampers
the maximum potential for ecosystem development and exerts additional pressure on the sensitive
habitats in the national park area. The study showed that increased hydraulic connectivity would benefit
several stakeholders that preferred the ecological development of the floodplain habitats. However,
multiple uses including fishery, agriculture and recreation, exploring the maximum potential in line with
national park regulations, were also possible under the increased hydraulic connectivity options. The
largest trade-offs were quantified to be at 0.50 score between the ecological condition of the aquatic
habitats and the drinking water production and 0.49 score between the ecological condition of the
terrestrial habitats and the drinking water production. At this point, the drinking water production was
traded-off with 0.40 score, while the ecological condition of the aquatic habitats and the ecological
condition of the terrestrial habitats were traded off with 0.30 and 0.23 score, respectively. The majority of
the stakeholders involved preferred the management options that increased the hydraulic connectivity
compared with the current situation which was not preferred by any stakeholders. These findings
highlight the need for targeted restoration measures. By that, it is recommended that additional
measures to ensure reliable drinking water production should be developed, if the higher connectivity
options would be implemented. In the next step it is recommended to include cost and flood risk criteria
in the decision matrix for more specific developed measures. The research showed that pair-wise tradeoff figures provided a useful means to elaborate and quantify the real trade-offs. Finally, the research also
showed that the use of multi criteria decision analyses should be based on a participatory approach, in
which the process of arriving at the final ranking should be equal or more important than the outcome of
the ranking itself.
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Wetland management
Wetland ecosystem services
Floodplain restoration
Trade-off analysis
Multi criteria decision analysis
Lobau wetland
* Corresponding author. Tel.: þ47 47234328.
E-mail addresses: [email protected] (S. Sanon), [email protected]
(T. Hein), [email protected] (W. Douven), [email protected]
(P. Winkler).
1
Tel.: þ43 7486 20060 40, þ43 1 47654 5229; fax: þ43 7486 2006020, þ43 1
47654 5217.
2
Integrated River Basin Management UNESCO-IHE Institute for Water Education
Westvest 7, 2601 AX Delft, The Netherlands. Tel.: þ31 15 215 1886; fax: þ31 6 1383
4493.
3
Tel.: þ43 1 47654 5229; fax: þ43 1 47654 5217.
0301-4797/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.jenvman.2012.06.008
1. Introduction
Riparian zones, floodplains and river-marginal wetlands are key
landscapes of strategic importance to human society (Acreman
et al., 2007; Amezaga et al., 2002; Mitsch and Gosselink, 2000;
Thoms, 2003; Tockner and Standford, 2002). They provide important ecosystem services such as climate regulation, nutrient cycling,
retention of flood waters, infiltration and stabilization of groundwater levels for drinking water abstraction and recreational
160
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
services in urbanized areas (Hoehn et al., 2003; MEA, 2005; TEEB,
2010). It is estimated that more than half of the original wetlands
in the world have been lost due to anthropogenic modifications
(Fraser and Keddy, 2005; Mitch, 2005) such as drainage for agricultural production (e.g. Kanyarukiga and Ngarambe, 1998; Walter
and Shrubsole, 2003), construction of dams for hydropower,
urbanization and increased pollution loads in general (Revenga
et al., 2000). In Europe, the loss of natural riverine wetlands is
estimated to be about 95% (Tockner and Standford, 2002). The
remaining riverine wetlands are also altered by straightening and
dredging of river channels for navigation purposes (Hesselink,
2002) and confined (Jungwirth et al., 2002) by flood protection
measures such as construction of levees and embankments (Henry
et al., 2002; Hey and Philippi, 2006; Mauchamp et al., 2002). The
reduced floodplain dynamics has turned many riverine wetlands
into static, shallow and lake-like systems (Schiemer et al., 2006;
Hohensinner et al., 2008), with a reduced integrity of floodplain
ecosystem functions (Hale and Adam, 2007; Simenstad et al., 2006;
Weigelhofer et al., 2011). The degradation of floodplain ecosystem
functions is particularly far progressed in urban settings. Faulkner
(2004) and Groffman et al. (2003) indicate that the majority of
urban floodplains have already been settled or converted into other
ecosystem types, urban settlements, industrialized areas or arable
land. The remaining aquatic habitats are often disconnected from
the river or are severely altered by intense human uses (Grayson
et al., 1999; Hein et al., 2006; Zedler and Kercher, 2005). This
often leads to unbalanced floodplain conditions such as increased
sedimentation and siltation processes and enhanced eutrophication processes caused by local diffuse and point pollution sources
(Henry et al., 2002; Shields et al., 2008). Today, urban floodplains
are also increasingly used for recreational activities (Anderson,
1995) like hiking, fishing and swimming. Although these latter
activities create additional pressure on the sensitive floodplain
ecosystems, they also raise the demand for protection and
conservation of nature (Hein et al., 2006; Schaich, 2009). Therefore,
the future demands for socio-economic activities and other societal
uses, but at the same time, the importance of protecting these
valuable floodplain areas, emphasizes the need for new management strategies (Hein et al., 2006; Hopfensberger et al., 2006; Orr
et al., 2007; Tong et al., 2006).
The development of such new management strategies can
benefit from a multi criteria decision analysis (MCDA) approach due
to the potential conflicts and trade-offs between different ecological, livelihood, water treatment and water supply functions. This
approach is widely used to support the solution of multi objective
decision making problems, where conflicts exist between different
objectives (Tecle et al., 1998; Xevi and Khan, 2005). Multi criteria
decision analysis aims at structuring the planning and decision
making process (Mendoza and Martins, 2006). It provides a means
to elaborate and quantify the explicit differences between the
management objectives and hence can help in increasing the
transparency of the decision-making process. Understanding the
trade-off relationships between ecological, economic and social
objectives is important in designing policies to manage or restore
ecosystems (Cheung William and Sumaila, 2007; Reichert et al.,
2005; Turner et al., 2000). Designing effective programs and policies to restore lost or degraded ecosystems also requires evaluation
and prioritization of the management options (Prato, 2003). In
addition, multi criteria decision analysis techniques allow the
incorporation of stakeholders in decision making processes (Brown
et al., 2001a; Linkov et al., 2004).
The main aim of the research was to investigate the potential
role of multi criteria decision analysis in wetland management,
more specifically in the quantification of trade-offs between
objectives of key stakeholders involved in wetland management.
The paper presents the results of an application of a multi criteria
decision analysis to evaluate a set of management options for the
Lobau floodplain, an urban floodplain along the Danube River in
Vienna, Austria. For this purpose, a distance based algorithm was
used to quantify and elaborate trade-offs between two conflicting
objectives. The paper further explores what management options
are the most preferred ones according to the preferences of
stakeholders and, following that, also which option could theoretically offer the ‘best’ compromise between the group of stakeholders. The Mulino decision support tool called mDSS4 (Giupponi,
2007) was used to analyze the data.
2. Study area- the Lobau floodplain
The Lobau is a 23 km2 floodplain formed by the discharge
patterns of the Upper Danube River (Tritthart et al., 2011). The
floodplain area is located on the left river bank of the Danube
River at the eastern border of the Vienna City in Austria (Fig. 1). In
its pristine condition, the Lobau area was one of the widest
floodplains amongst the Austrian anabranching Danube River
section, where braided river arms constituted the dominant
floodplain habitats (Hohensinner et al., 2008). As part of
improvements for navigation and flood protection, the Danube
River was straightened and embanked substantially between 1870
and 1880, which changed the morphological character of this river
section from an anabranching situation to a single channel system
(Zornig et al., 2006). Since then, the former dynamic floodplain
has been disconnected from the Danube River channel and
changed floodplain development primarily due to altered
geomorphological dynamics (Hohensinner et al., 2008). At
present, the hydrodynamics of the Lobau is characterized as
a groundwater-fed and back-flooded lake system with long
periods of low to negligible flow (Janauer and Strausz, 2007). The
reduced hydraulic connectivity has resulted in sediment accumulation and a reduction of water levels at the floodplain scale
and subsequently enhanced the terrestrialization processes
(Weigelhofer et al., 2011). Subsequently, the habitat distribution
and vegetation cover has also changed (Hein et al., 2007) which
together with prevailing sedimentation and eutrophication
processes has resulted in a gradual decrease of size and quality of
the aquatic habitats (Kirschner et al., 2001).
The recent urban expansion of Vienna into the north-eastern
part of the Lobau has turned the upper part of the Lobau (Fig. 1)
into a highly urbanized floodplain, contributed to the degradation
of the natural floodplain (Hohensinner et al., 2004; Schiemer et al.,
1999). Urban development has also led to an increase in the
number of visitors to the Lobau, which adds further pressure on
sensitive habitats and species in the floodplain. Nevertheless, the
Lobau still contains a high aquatic, semi-aquatic and terrestrial
biodiversity (Reckendorfer et al., 1998; Baart et al., 2010). In 1996,
this floodplain area was designated as national park area and the
ecosystem management target was to rehabilitate the hydrological
connectivity approaching pre-regulation conditions again
(Schiemer et al., 1999). Hohensinner et al. (2008) show that without
sound management practices, most aquatic and semi-aquatic
habitats of the Lobau floodplain are expected to change further
and the floodplain will soon become a primarily terrestrial
ecosystem with major implications for its rich aquatic and
amphibic biodiversity (Hein et al., 2006). However, restoring the
natural floodplain conditions by increasing the surface connectivity
between the Lobau and the river channel, might impose adverse
effects on the potential groundwater abstraction and limit other
societal utilizations (Hein et al., 2008). Currently, the main uses of
the Lobau area include recreation, groundwater abstraction for
drinking water production, ecosystem development through
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
161
Fig. 1. Implementation of the hydraulic options (Hein et al., unpublished report). Delineation of the Lobau into three sub-areas including the Upper Lobau (UL), the Lower Lobau (LL)
and the Vorland Strip (VL). The Dotation point is the point that receives water input from the two inlets (UL1 and UL2) located in the Upper Lobau. Main features of the hydraulic
options are summarized in Table 2.
rehabilitation of functional processes and conservation of floodplain habitats and sport fishery (Hein et al., 2006).
3. Method and data
3.1. Multi criteria decision analysis
3.1.1. General approach
The decision analysis implemented in this study was based on
a multi criteria decision analysis (MCDA) framework. The iterative
process of MCDA typically consists of the following steps: defining
objectives, selecting set of criteria to measure the objectives,
specifying the alternatives, transforming the criterion scales into
commensurable units, pre-evaluating of the evaluation matrix,
assigning weights to the criteria that reflect decision maker’s
preferences, selecting and applying mathematical algorithms for
ranking alternatives, performing a sensitivity analysis and
choosing or recommending alternatives (Howard, 1991; Keeney,
1992). The objective of the MCDA in this study was to evaluate
and quantify the explicit trade-offs between key ecosystem
services related to the objectives of the stakeholders of the Lobau.
Traditional MCDA often deals with only the implicit trade-offs in
the form of weights expressed by the stakeholders involved (e.g.
Brown et al., 2001b; Van Huylenbroeck, 1998). In this study, the
purpose of the trade-off analysis was to make the trade-offs
between the stakeholder’s objectives explicit by giving it
a numerical value and hence enhance transparency. Integration of
trade-off analysis in a general multi criteria decision strategy is
addressed in Grierson (2008). The next two paragraphs will
elaborate the MCDA methodology applied to quantify the tradeoffs and to rank the management options.
3.1.2. Quantification of trade-offs
Standardized criteria scores were used to construct pair-wise
trade-off figures in which the Pareto ecosystem front between the
two criteria is formed by the non-dominated options between the
two conflicting criteria (Van Huylenbroeck, 1998). A management
option is non-dominated, if there are no other options in the
decision space that score better for one criterion at least, and also
which scores at least as well as all options for the other criteria (Lee
et al., 1996). The sub-optimal (or the dominated) options do not
inherit trade-offs (by this definition) as one objective can be
improved without causing loss in the other (Cheung William and
Sumaila, 2007; Lautenbach et al., 2010). Trade-offs between
management criteria exist, if the optimum score of these criteria is
achieved by different options in the decision space. Thus, the nondominated management options, that lay on the Pareto
(ecosystem) front, form the curve of the trade-offs between the two
criteria evaluated (see solid line in Fig. 2) (Tappeta et al., 2000). The
trade-off between the two management criteria in this study was
quantified by calculating the shortest distance from a theoretical
ideal solution (in which both criteria score equals 1) to the nondominated option(s) that provided this shortest distance (see
dashed line in Fig. 2). The approach of measuring the closest
distance(s) to reference point(s) to rank the management options
according to these distances was suggested by Wierzbicki in 1980
(Deb et al., 2006; Wo
zniak, 2007).
3.1.3. Ranking of management options
The ranking of the selected management options according to
the preferences of the decision makers was based on two decision
rules: the Simple Additive Weighting (SAW) and the Technique for
Order Preference by Similarity to Ideal Solution (TOPSIS) (Giupponi,
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S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
Fig. 2. Theoretical trade-off figure based on normalized criteria scores ranging from 0 to 1. The trade-off curve between the two criteria is formed by the non-dominated options
that forms the ecosystem front.
2007). SAW uses the additive aggregation of the criteria outcomes
and is a commonly used decision rule in single dimensional decision making problems because of its simplicity (Pohekar and
Ramachandran, 2003). TOPSIS is a popular compromise decision
rule and defines the most preferred option as the one that is closest
to the ideal positive option but at the same time also furthest away
from the ideal negative option (Giupponi, 2007). The two decision
rules were applied to check the robustness of their ranking results.
Then, the Borda group compromise decision rule was applied to
compromise the individual rankings obtained by the SAW and
TOPSIS decision rules. To support this process, the Mulino Decision
Support tool (mDSS4) was used (Giupponi, 2007). The mathematical algorithms of the standardization technique and decision rules
applied in this study are beyond the scope of this paper.
3.2. Data
The quantification of the trade-offs between the stakeholder’s
objectives related to key ecosystem services of the Lobau floodplain
required various data sets. Data regarding the stakeholder groups
and their interests in the Lobau floodplain was collected by the EU
FP7 WETwin project (van Ingen et al., unpublished report). Data on
management options, management criteria and decision maker’s
preferences were collected by the Optima Lobau project in collaboration with the main stakeholders of the Lobau floodplain (Hein
et al., unpublished report).
3.2.1. Stakeholder groups and their interests
Stakeholder groups of the Lobau floodplain can be identified at
different spatial scales including the local, wetland, municipal,
national, provincial and international scales. The interests of the
main stakeholder groups differed between these scales (Table 1).
Ecosystem services like fishery, hunting, agriculture and recreation
were of interest to the adjacent municipalities at the local scale but
also to the Associations for Hunting and Fishing of Vienna and
Lower Austria and to the Chamber of Commerce of Vienna and
Lower Austria at the provincial scale. The conservation of nature
was of interest to the stakeholder groups at the wetland, municipal,
national, provincial and international scale. The stakeholder groups
that preferred a combination of interests were typically from
government. This difference was especially visible at the national
scale in which the interest of the Environmental NGO was primary
nature conservation, while the interests of governmental organizations, including the Federal Ministry for Environment and the
Federal Ministry for Traffic, were both nature conservation and
flood protection (Table 1).
3.2.2. Management options
The management responses analyzed in this study aimed at
a more active use of the floodplain for flood attenuation by
increasing the hydraulic connectivity with the Danube river
channel and hence stimulating the development of aquatic habitats
and enhance geomorphic dynamics (Fig. 3). The stakeholders
involved in the Optima Lobau project rejected hydraulic options
that would increase the flood risk, and also expressed that costs of
management options should not be a matter of concern in the first
assessment. Given these boundary conditions, 4 hydraulic options
ranging from complete disconnection downstream (Fig. 1) to fullreconnection with the Danube River channel upstream (Table 2)
were developed. The main features of these 4 hydraulic options
including the Current Status option are summarized in Table 2. The
hydraulic connectivity with the Danube River channel and the
openings are coded according to the option’s position in the Upper
Lobau (UL) and the Lower Lobau (LL). The locations of the main
features presented in Table 2 are shown in Fig. 1.
In the current situation (Current Status option), water from the
Danube channel can enter the Lower Lobau during high water
levels through a small opening (Schönauer Schlitz) in the main
levee located at the downstream end and flows out in case of
receding water levels (Fig. 1). Groundwater exchange with the main
river channel also contributes to water supply of floodplain waters
(Janauer and Strausz, 2007). In the current situation, surface water
input is allowed at a rate of 0.5 m3 s1 (Table 2) through
a controlled opening (UL1) in the Upper Lobau (Fig. 1).
The Disconnection option closes off the downstream opening
point (Schönauer Schlitz) and further isolates the Lobau from the
Danube river channel (Table 2). In this option, the hydraulic
connectivity is mainly driven by the existing controlled opening at
the Upper Lobau (UL1) with a maximum rate of 1.5 m3 s1 (Table 2).
The Enhanced connectivity option increases the inflow from the
existing controlled two openings at the Upper Lobau (UL1 and UL2)
to a rate of 5 m3 s1 each. Thus, the Dotation point, that receives the
input water from the two controlled points in the Upper Lobau area,
equals 10 m3 s1 (Table 2). This hydraulic option does not increase
the hydraulic connectivity of the Lower Lobau area and the backflow flooding point (Schönauer Schlitz) remains open.
The Partial Reconnection option increases the water input in the
Lower Lobau (LL2) at a rate of 20 m3 s1 during low water discharge
(LW) in the Danube river channel and at a rate of 125 m3 s1 during
mean water discharge (MW). This additional water input will create
a new side arm in the Lower Lobau area (LL2). Therefore, it is
necessary to enlarge the outflow area (Fig. 1) by removal of
embankments in the Lower Lobau and also enlarge the downstream
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
163
Table 1
Main stakeholder groups of the Lobau and their interests (van Ingen et al., unpublished report).
Scale
Stakeholder groups
Main stakeholders of the Lobau
Local
Adjacent Municipalities
Wetland
Municipal
National
Provincial
International
National Park Authority
(National Park GmbH)
Governmental Administration units for:
Water Management Authority of Vienna,
Forestry,
Drinking Water, and
Nature Protection
Nature Conservation NGOs (WWF, Bird Life)
Federal Ministry for Environment and
Federal Ministry for Traffic
Governments of Vienna and Lower Austria,
Governmental Administration unit for
Environment and Water Management,
Governmental Administration unit for
Spatial Planning
Associations for Hunting and Fishing of Vienna
and Lower Austria, Chamber of Commerce
of Vienna and Lower Austria
(members of the National Park Advisory Board)
Advocacy for the Environment of Vienna
and Lower Austria
International Commission for the Protection
of the Danube River
Type
Interest
Civil Society
Fishery, recreational, flood protection and health issues
(related to abundance of mosquitoes)
Nature conservation, national park, research and education
Public Sector Regulator,
Research and Education
Governance Structure,
Donor/Funder
Flood protection, nature conservation, drinking water
supply and recreation
NGO
Governance Structure,
Donor/Funder and Advisory
Governance Structure,
and Donor/Funder
Nature conservation
Nature conservation, flood protection and water ways
Civil Society/NGO and
Advisory
Hunting, fishing, agriculture
Governance Structure
Legal questions regarding nature conservation
Governance Structure
Harmonize all interests and ecosystem protection
opening (Table 2) to flush out the input water. The rationale for the
creation of a new side arm is to compensate for the loss of aquatic
habitats and, at the same time, to preserve the developed highly
endangered lentic habitats in the upper part of the Lobau. Under this
hydraulic option, the hydraulic connectivity of the Upper Lobau
with the Danube river channel is only driven by the controlled
inflow point (UL1) at a rate of 1.5 m3 s1.
In the Full Reconnection option, the inflow rate from the existing controlled opening (UL1) and the second one (UL2) in the Upper
Lobau increase to a rate of 5 m3 s1 each, leading to a total of
10 m3 s1 for the Dotation point (Table 2). Reactivation of four
former side arms through four water input points (LL1eLL4) to
allow uncontrolled water input are re-established in the Lower
Flood protection, nature conservation, drinking water
supply, sanitation, recreation
Lobau (Fig. 4). The different inflow rates, at the four input points,
are dependent on the riverine discharge and the local elevation of
the side-arms starting at low flow (Table 2). The substantial water
input makes it necessary to enlarge the outflow point at the
downstream end by partial removal of the flood protection dyke in
the Lower Lobau (Fig. 1).
3.2.3. Future use-scenarios
In addition to these hydraulic options, five future use-scenarios
were identified, each having one dominant utilization of the Lobau
floodplain (Hein et al., unpublished report): ecological development (ECO), drinking water production (DRINK), recreation (REC),
agriculture (AGRI), and fishery (FISH). The five future use-scenarios
Fig. 3. Preferences of the representatives of the nine stakeholder groups (Hein et al., unpublished report). The weights were obtained by dividing the actual allocated points to the
total of five points.
164
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
Table 2
Main features of the 4 hydraulic options including the current status (Hein et al., unpublished report). LW ¼ low water discharge in the Danube river channel, MW ¼ mean
water discharge in the Danube river channel. UL ¼ Upper Lobau, LL ¼ Lower Lobau. The locations of the water input areas UL1, UL2, LL1, LL2, LL3 and LL4 are shown in Fig. 1. The
Dotation point is the point that receives water input from the upstream area through the two inlets (UL1 and UL2) located in the Upper Lobau area.
Implementation of
the hydraulic options
Water input
Upper Lobau
Lower Lobau
UL1
UL2
Dotation point
LL1
LL2
LL3
LL4
Current status
Disconnection
0.5 m3s1
1.5 m3s1
e
e
0.5 m3s1
1.5 m3s1
e
e
e
e
e
e
e
e
Enhanced connectivity
Partial reconnection
5 m3s1
1.5 m3s1
5 m3s1
10 m3s1
1.5 m3s1
e
e
e
e
e
e
Full reconnection
5 m3s1
5 m3s1
10 m3s1
e
20 m3s1
(LW)
125 m3s1
(MW)
15 m3s1
(LW)
100 m3s1
(MW)
20 m3s1
(MW)
20 m3s1
(MW)
15 m3s1
(LW)
100 m3s1
(MW)
were developed in line with the regulations and the management
plan of the National Park Authority (National Park Donau-Auen,
2004). The purpose of the scenarios was to assess the impact of
maximizing one single utilization, but within the maximum limits
set by the regulations of the National Park Authority. Generally this
implied that in each dominating use-scenario, the areas for other
uses were reduced. In the fishery scenario, a baseline study was
used to estimate the maximum fishing activities based on the
fishing licenses (Hadwiger et al., 1995). In the agriculture usescenario, all classified farmable areas in the Lobau, as defined by
the National Park Authority, were assumed to be cultivated. In the
recreation use-scenario, a maximum use frequency was estimated
based on the expected population growth in the next 20 years in
the vicinity of the Lobau. In the drinking water production usescenario, the maximum values were estimated based on the
existing water rights (permits). In all other use-scenarios only the
mean values of the last year’s water production were used and the
other uses were only allowed outside the sensitive areas (of influence) for drinking water production, defined by the modeled area
around each well of a groundwater residence time of 60 days. In the
Schönauer
Schlitz - the
back flow
flooding point
Outflow
area
Open
Closed
(during floods)
Open
Open
Open
Closed
Open
Enlarged
Open
Enlarged
ecological development use-scenario, all other uses including
agriculture, fishery and recreational activities were kept at
a minimum.
The total number of management options identified for this
study comprised of 21 management options (4 hydraulic options
times 5 use scenarios, plus the Current Status). In the results
section, a management option is referred to as a combination of the
hydraulic option and the use-scenario. For example the disconnection hydraulic option and the ecological development usescenario is referred to as ‘Discon_ECO’.
3.2.4. Management criteria and indicators
Through predictive hydrological, ecological and socio-economic
models in addition to qualitative expert judgments, a total of 76
impact indicators were identified and assessed for each management option. A more detailed description of the models and the
individual indicators can be found in Hein et al. (2006) and Hein
et al. (unpublished report). The model structure for the hydrological
and ecological models can be found in Weigelhofer et al. (2006) and
Baart et al. (2010) for the aquatic vegetation. The model framework
Fig. 4. Impact on the ecological condition of the terrestrial habitats, ecological condition of the aquatic habitats and potential drinking water production. The x-axis represents the
increasing hydraulic connectivity and the current status is marked by the yellow bar. The main hydraulic options are also listed in the x-axis. (For interpretation of the references to
color in this figure legend, the reader is referred to the web version of this article.)
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
consisted of a digital terrain model for each management option,
a spatial explicit (cell size 10 10 m) coupled hydrodynamic model
assessing daily surface and ground water levels and flow conditions
for each cell and combining these results with spatial explicit
hydro-ecological models using hydrological parameters such as e.g.
days of connectivity, water levels in floodplain water bodies as
input to assess key ecological properties. Historical analyses of the
hydrogeomorphic conditions were used to define the preregulation conditions and assess hydromorphologic indicators
such as distribution of floodplain water body types, mean depth at
specific riverine discharges (Hohensinner et al., 2008). A statistical
approach based on long term data series (minimum of 4 years of
available data) was used in the hydro-ecological models (Baart
et al., 2010; Hein et al. unpublished report, Mayer, 2007).
To analyze and quantify the trade-offs, indicators for each
management criterion were selected and aggregated (Table 3).
Selection and aggregation of individual indicators was carried out
for the indicators with the same value function (minimize or
maximize) until the best possible discrimination between the
management options were achieved. The value functions used to
standardize the selected and aggregated indicators were related to
the objectives of the stakeholders. The benefit-type value function
was used to normalize those impacts stakeholders were expected
to maximize, while the cost-type value function was used to
normalize those impacts stakeholders were expected to minimize
(Giupponi, 2007).
3.2.5. Stakeholders preferences
Data about preferences on management criteria was collected
by consulting nine stakeholders representing each of the abovementioned stakeholders groups (Table 1). These representatives
were asked to indicate their preferences on the management
criteria by allocating a total of five points (Hein et al., unpublished
report) (Fig. 3). In this study, we assume their preferences to be
representative for each stakeholder group. The most important
criterion for the Governmental unit for Environment and Water
Management was drinking water production. The ecological
condition of the aquatic habitats, the ecological condition of the
terrestrial habitats and recreation were of moderate importance,
but less than drinking water production. The Water Management
Authority valued the ecological condition of the aquatic habitats as
most important compared to recreation, ecological condition of
terrestrial habitats and drinking water production. The Spatial
Planning Administration valued the ecological condition of the
165
aquatic habitats, the ecological condition of the terrestrial habitats
and drinking water production as equally important. The Nature
Protection Administration valued the ecological condition of the
terrestrial habitats higher than the ecological condition of the
aquatic habitats, while the National Park Authority and the International Commission valued the ecological condition of the aquatic
habitats and the ecological condition of the terrestrial habitats as
equally important. The representative of the Local Village valued
fishery higher than any other criteria.
4. Results
The results chapter is divided into three parts. The first part
evaluates the impacts of the 21 management options including the
current status on the management criteria presented in Table 3. The
second part elaborates and quantifies the major trade-offs between
management criteria by using trade-off figures. The third part ranks
the management options according to the preferences of the nine
stakeholder groups (Fig. 3) as obtained by the two decision rules.
The identification of the best compromised option will be included
in this last part.
4.1. Impacts on the management criteria
The results show that increased hydraulic connectivity, through
surface water exchange with the main channel of the river,
increased the available aquatic area and improved the ecological
condition of the aquatic habitats in general and further enhanced
the ecological condition of the terrestrial habitats. The latter effect
is linked to increasing exposure of terrestrial areas to more frequent
flood inundation that enables development of typical floodplain
vegetation. The enhanced hydraulic option showed no improvement of the ecological condition of the terrestrial habitats at the
floodplain scale (Fig. 4). Therefore, the Full Reconnection option,
that rehabilitates the surface water connection between the entire
Lobau and the main river channel, maximized the ecological
condition of the aquatic water bodies, the potential areas for fishing
activities and the ecological condition of the terrestrial habitats at
the floodplain scale (Figs. 4 and 5). Fostering the hydrological
dynamics also increased the available areas for fishing (Fig. 5).
On the other hand, increased hydraulic connectivity seemed to
reduce the potential for drinking water production (Fig. 4). This is
explained by the reduction of the groundwater residence time due
increased surface water influence. The Disconnection hydraulic
Table 3
Management criteria and selected and aggregated indicators (Hein et al., unpublished report). The delineation of the Lobau floodplain into three sub-systems including Upper
Lobau, Lower Lobau and Vorland is shown in Fig. 1.
Management criteria
Selected and aggregated indicators
Stakeholder objective/value function
Ecological condition of
the aquatic habitats
Sum of suitable habitats for selected species and other indicators
for the ecological condition of the water bodies including; available
phytoplankton biomass in the connected water bodies, area of
Ranunculus fluitans, values for hydrophytes, values for all macrophytes,
species number of macrophytes, percentage of shallow areas
(<0.5 m water depth at summer mean water), area of connected water
bodies at mean water and size of water bodies with a mean Chlorophyll-a
content > 25 mg l1 during the vegetation period
Lengths of hiking trails, public footpaths, visitor tracks, and bicycle paths
(all in Upper Lobau and Lower Lobau)
Total area of fishing waters in hectare for the whole Lobau floodplain
Sum of area with cereal, vegetable and potatoes in the whole Lobau
Sum of inundated areas at annual high water in Upper Lobau, Lower
Lobau and Vorland Area, areas of helophytes in Upper Lobau, Lower Lobau
and Vorland, species richness, dynamic vegetation elements and degree
of naturality of floodplain vegetation
Sum of days of Danube surface water influence on the 5 drinking water
wells and the production days in one well suspended due to flood water input
Benefit value function- to be maximized
Potential recreation
Potential fishery
Potential agriculture
Ecological condition of
the terrestrial habitats
Potential drinking water
production
Benefit value function- to be maximized
Benefit value function to be maximized
Benefit value function to be maximized
Benefit value function- to be maximized
Cost value function to be minimized
166
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
Fig. 5. Impact on the agriculture, fishery and recreation. The x-axis represents the increasing hydraulic connectivity and the current status is marked by the yellow bar. The main
hydraulic options are also listed in the x-axis. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
option and the Current Status maximized the potential drinking
water production. The Disconnection option also maximized the
potential agriculture and potential recreation (Figs. 4 and 5).
However, the Disconnection option minimized the ecological
development (of the aquatic and terrestrial habits) and also the
potential areas for fishing at the floodplain scale. The Full Reconnection option did not result in any significant impacts on the
potential agriculture and the potential recreation criteria (Fig. 5).
The results indicate that the Disconnection option might lead to
larger conflicts between the management criteria as the increased
hydraulic options did not result in any significant impacts on
potential agriculture and recreation. Therefore, increased hydraulic
connectivity seems to reduce the potential conflicts as the Current
Status option only maximized the drinking water production.
Based on these results, it is reasonable to expect a substantial tradeoff between the management criteria that scored high under the
Full Reconnection option (like the ecological condition of the
aquatic habitats, the ecological condition of the terrestrial habitats
and the potential fishery) and the potential drinking water
production criterion (Figs. 4 and 5).
Important interactions between the management options and
the five use-scenarios were also apparent. For instance, the
ecological development (ECO) use-scenario had a negative impact
on potential fishery, potential agriculture and potential recreation
in each hydraulic option, as the area for other uses was limited
(Figs. 4 and 5). On the other hand, the recreation (REC) use-scenario
reduced for each hydraulic option the maximum potential for the
development of aquatic habitats (Fig. 4), maximum potential for
fishery (FISH) and maximum potential for agriculture (AGRI)
(Fig. 5), which can be due to the fact that their areal extensions
were reduced. The recreation use-scenario (REC) also reduced the
maximum potential for the development of terrestrial habitats in
each hydraulic option (Fig. 4). The drinking water (DRINK) usescenario reduced the maximum potential for drinking water
production in each hydraulic option due to the increased groundwater abstraction rates and thus, a limited availability during
different periods compared to the current situation.
4.2. Quantification of the major trade-offs
In this section, we elaborat and quantify the trade-offs between
management criteria resulting from the previous section by using
trade-off curves. We will focus on the three major trade-offs
resulting from the previous section: between drinking water and
Fig. 6. Trade-off between ecological condition of the aquatic habitats (y-axis) and potential drinking water production (x-axis). The management option (s) that provided the
shortest distance to the theoretical solution is shown in bold.
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
167
Fig. 7. Trade-off between ecological condition of the terrestrial habitats (y-axis) and potential drinking water production (x-axis). The management option (s) that provided the
shortest distance to the theoretical solution is shown in bold.
aquatic ecology, drinking water and terrestrial ecology, and
drinking water and fishery.
The trade-off curve between the ecological condition of aquatic
habitats and drinking water production (Fig. 6) showed a negative
linear relationship between the two criteria. The Pareto front
between the two criteria was formed by the Ecological Development (ECO) use-scenario in each hydraulic option except the
Current Status. This is caused by the positive impact the ecological
development (ECO) use-scenario will have on the ecology of the
aquatic habitats in each hydraulic option as compared to other usescenarios. In this curve, the Partial Reconnection option with
dominant Ecological Development (ECO) was located at the point
that provided the shortest distance to the theoretical ideal solution
(Fig. 6). The distance from this location to the ideal solution point, is
0.50. At this location in the figure, the ecological condition of the
aquatic habitats is traded off with a 0.30 score and the drinking
water production with a 0.40 score (Fig. 6).
The trade-off curve between the ecological condition of terrestrial habitats and potential drinking water production was formed
by the Current Status, Partial Reconnection and Full Reconnection
options (Fig. 7). Their hydraulic gradients and the expected benefits
are apparent as 4 clusters on the trade-off figure. The Pareto front
between the two criteria shows that the Partial Reconnection
option for the use-scenarios Ecological Development (ECO), Agriculture (AGRI) and Fishery (FISH), provided the point with the
shortest distance to the theoretical ideal solution which maximizes
both criteria (Fig. 7). This can be explained by the negative impact
the drinking water production (DRINK) use-scenario had on
potential drinking water production in each hydraulic option. At
this location in the figure, the potential drinking water production
is traded off with a 0.4 score, while the ecological condition of the
terrestrial habitats with a 0.23 score. Therefore, the trade-off
between the two criteria is quantified at 0.46 (Fig. 7).
The trade-off curve between fishery and drinking water
production was formed by the Agriculture (AGRI) and Fishery
(FISH) use-scenarios in each hydraulic option except the Current
Status (Fig. 8). This result can be explained by the negative
impact the recreation (REC) use-scenario had on potential fishery
and the negative impact the drinking water (DRINK) use-scenario
had on potential drinking water production in each hydraulic
option. The ecological development (ECO) use-scenario reduced
the potential fishery because other societal utilizations were kept
at a minimum (except from drinking water production). In this
Pareto front, the Enhanced Connectivity option with the Agriculture (AGRI) and Fishery (FISH) use-scenarios provided the
shortest distance to the ideal solution. At this location in the
figure, the potential fishery is traded off with a 0.3 score and the
potential drinking water production with a 0.02 score (Fig. 8).
Subsequently, the trade-off between the two criteria is quantified
at 0.3 (Fig. 8).
In summary, the largest trade-offs were between ecological
development (of the aquatic and terrestrial habitat) and the
potential drinking water production. The two trade-off curves show
a strong negative and almost linear relationship between the
Fig. 8. Trade-off between potential fishery (y-axis) and potential drinking water (x-axis). The management option (s) that provided the shortest distance to the theoretical solution
is shown in bold.
168
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
conflicting criteria indicating a maximum trade-off at the two
hydraulic extremes; Isolation and Full Reconnection.
4.3. Ranking of management options
This section presents the individual rankings (Table 4) of the 21
management options according to the preferences of nine representatives of the stakeholder groups involved as presented in
section 3.2.
The results of the Simple Additive Weighting (SAW) decision
rule show that six of nine stakeholder groups preferred one of the
use-scenario options of the Full Reconnection option (Table 4).
These six stakeholder groups included International Commission
for River Protection, Local Village, Environmental NGO, Water
Management Authority of Vienna, National Park Authority and
Nature Protection Administration. These were also the stakeholder
groups that valued the ecological condition of the aquatic habitats,
the ecological condition of the terrestrial habitats and the potential
fishery higher than any other criteria (Fig. 3). The representative for
the Governmental unit for Water and Environment and the Spatial
Planning Administration both valued the ecological conditions of
the floodplain (i.e. terrestrial and aquatic) and the drinking water
production equally high (Fig. 3). This is in line with the outcomes of
SAW rankings showing that the Partial Reconnection option with
the fishery (FISH) use-scenario was the most preferred option for
both. For the Drinking Water Administration, who valued the
drinking water production criterion higher than any other criteria,
the SAW rankings resulted in the reduced hydraulic connectivity
options as their most preferred option.
The Disconnection option with the agriculture (AGRI) usescenario was the most preferred option for the Drinking Water
Administration, because they more clearly assigned a moderate
importance to the potential agriculture criteria (Fig. 3).
The results of the Technique for Order Preference by Similarity
to Ideal Solution (TOPSIS) rankings show that four out of the nine
stakeholder groups including the Local Village, Environmental
NGO, National Park Authority and Nature Protection Administration, preferred one of the use-scenario options of the Full Reconnection option (Table 4). The Environmental NGO, National Park
Authority and Nature Protection Administration valued the
management criteria, which scored maximum under the Full
Reconnection option (Figs. 4 and 5), highest (Fig. 3). Surprisingly,
TOPSIS also resulted in the Full Reconnection as the most preferred
hydraulic option for the Local Village as well (Table 4). This stakeholder group indicated the potential fishery criterion (which was
maximized under the Full Reconnection hydraulic option) as the
highest, but also placed a moderate importance on the potential
drinking water criterion (which scored minimum under the Full
Reconnection option) (Fig. 4). For the International Commission for
River Protection, Spatial Planning Administration, Governmental
unit for Environment and Water Management, Drinking Water
Administration and the Water Management Authority of Vienna,
which also indicated the importance of the potential drinking
water criterion, the TOPSIS suggested the lower hydraulic options
as their most preferred option (Table 4). The Enhanced hydraulic
option with the recreation (REC) use-scenario was the most
preferred option for the Spatial Planning Administration and
Governmental unit for Environment and Water, and the Disconnection option with the agriculture (AGRI) use-scenario for the
Drinking Water Administration. The Partial Reconnection option
with ecological development (ECO) was the most preferred
hydraulic option for the International Commission and the Partial
Reconnection with the fishery (FISH) use-scenario for the Water
Management Authority of Vienna. The difference is explained by
the fact that the International Commission for River Protection and
the Water Management Authority of Vienna gave less importance
Table 4
Ranking of the management options according to the preferences of the stakeholders. Results were obtained by the mDSS4 software (Giupponi, 2007). The preferences of the
nine stakeholder groups are shown in Fig. 3. The management options are arranged according to their increasing hydraulic connectivity.
S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
to the potential drinking water (DRINK) criterion compared to the
Spatial Planning Administration, Governmental unit for Environment and Water and the Drinking Water Administration (Fig. 3).
Based on the SAW rankings, the Borda group compromise
decision rule resulted in the Full Reconnection with dominant
drinking water production as the best compromised option for all
nine stakeholder groups. This hydraulic option was the best
compromised option and identified as the most preferred option by
the majority of the involved stakeholders (Table 4). The implementation of this hydraulic option, however, is associated with
increased vulnerability for drinking water production and
presumable higher costs. This will require additional measures to
secure a reliable drinking water production and limitation of other
uses within the sensitive areas for groundwater abstraction as
defined by the zone of 60 days of groundwater residence time.
The Borda group compromise rule resulted in the Partial
Reconnection option with dominant fishery as the best compromised management option for all nine stakeholder groups. This
hydraulic option was also the option that provided the shortest
distance to the theoretical ideal solution in the two largest tradeoffs between ecological development and drinking water production (Figs. 6 and 7). The Partial Reconnection with dominant fishery
(FISH) was the second best compromised option when compromising the SAW rankings. The Current Status and the Disconnection
options scored lowest in each round of Borda rankings, which
suggests it will be difficult to achieve a compromise around the
options that reduces the hydraulic connectivity as compared to the
current state.
5. Discussion and conclusions
The aim of this study was to apply a trade-off analysis approach
in an MCDA framework, to analyze and quantify the trade-offs
between the objectives of the stakeholders related to key
ecosystem services of the Lobau floodplain. A number of options
related to changing hydraulic connectivity and future use-scenarios
were assessed and ranked according to the preferences of the
management sectors involved. Based on this application we tried to
get more insights in the use of this approach in wetland
management.
The impact evaluation suggested that an increase in hydraulic
connectivity improved the ecological condition of the aquatic
habitats and increased the potential fishing waters in general
(Figs. 4 and 5). The increase in hydraulic connectivity also improved
the ecological conditions of the terrestrial habitats (Fig. 4), because
increased inundation area and duration during the annual flooding
benefits the ecological conditions of the natural floodplain vegetation in the terrestrial habitats (Rood et al., 2005). However, some
currently established aquatic habitats characterized by permanent
lentic conditions would decrease in aerial extent under the options
that increased the hydraulic connectivity, as these habitats are
shifted to frequently flowing waters. Thus, also suitable areas for
species indicating these habitat types would be reduced
(Reckendorfer et al., 2006). Such variations between the selected
and aggregated indicators are important to consider when interpreting the results of the subsequent trade-off analysis (Jollands
et al., 2003; Wanyama and Far, 2005). Therefore, the general
conclusion should rather be that an increase in water input (by
means of options that enhanced and partially reconnected the
Lobau with the main river channel) was necessary to establish
a dynamic exchange in order to conserve existing habitat qualities
and to develop new water bodies in the floodplain. However, a full
re-connection of all floodplain water bodies with the Danube river
channel without gaining new areas with more lentic type water
bodies might impose adverse impacts on the establishment of
169
communities closely associated to these lentic habitat conditions
(Baart et al., 2010).
Another point to discuss is the clustering of the management
options as shown in trade-off Figs. 6e8. This clustering can be
explained by the fact that the predictive models could not sufficiently distinguish between all the use-scenarios in each hydraulic
option. Either the models should be tuned in to be more sensitive to
the individual use-scenarios or the management options should be
revised to be more distinguishable from each other. A third possibility would be to include flood protection and cost criteria in the
final decision matrix. This inclusion would also make the criteria
space more exhaustive in terms of covering all stakeholder objectives (Table 1). But this could also have changed the preferences of
the stakeholders which, in turn, would have affected the rankings
of the management options and subsequently the best compromised option (Baker et al., 2001; Giove et al., 2009; Yoe, 2002).
Thus, further research, in collaboration with the stakeholders, could
be based on these findings, but with inclusion of flood risk and cost
criteria. This would also increase the potential use of trade-off
figures in a planning process; in particular, the steps to elaborate
the explicit trade-offs (Dietrich et al., 2007; Kelly et al., 1996; Kollat
and Reed, 2007; Lotov et al., 2005), quantification of the trade-offs
and the identification of the option(s) that provides the shortest
distance to the ideal solution.
The use of the pair-wise trade-off figures to analyze the potential trade-offs and the quantification of the trade-offs provided
a useful means to graphically elaborate the real trade-offs and not
the assumed ones. The use of pair-wise trade-off figures also
revealed the optimal solution space between the pair of objectives
(Lu and van Ittersum, 2003). However, the obvious limitation of
pair-wise trade-off figures is the fact that only two criteria can be
evaluated simultaneously (Chen et al., 2008). Also, the use of Pareto
trade-off figures to screen out the management options that were
dominated across all criteria in a multi criteria decision space was
not as straightforward as immediately thought. As demonstrated
by the trade-off figures, the same management options were either
dominated or non-dominated depending on the two criteria evaluated. Dominance is also rarely seen in planning and management
of water and environmental resources (Dodgson et al., 2009; Yoe,
2002). An alternative approach to screen out management
options in a multi criteria decision space could include the development of constraints on the management criteria (Chen et al.,
2008; Yoe, 2002). The application of threshold values to limit the
decision space to a smaller set of feasible management options
prior to ranking and selection could even be a necessity, as the
obvious limitations of multi criteria decision support tools in
general are the number of management options and criteria they
can compute. Another useful approach to limit the decision space is
to apply multi criteria decision rules that require definition of
threshold values e.g. the Preference Ranking Organization Method
for Enrichment Evaluation (PROMETHEE) and the Elimination and
Choice Translating Reality (ELECTRE) (Chen et al., 2008).
The difference between the two selected decision rules became
apparent in the rankings of the management options (Table 4). In
the Simple Additive Weighting (SAW) rankings, six of nine stakeholders preferred the Full Reconnection hydraulic option, because
the poor performance in the potential drinking water criterion was
fully compensated with a good performance in the two ecological
criteria and the potential fishery criterion. On the contrary, the
Technique for Order Preference by Similarity to Ideal Solution
(TOPSIS) suggested only four of the involved stakeholders preferred
the Full Reconnection option, while the remaining five preferred
the Disconnection, Enhanced and Partial Reconnection options
(Table 4). This is explained by the fact that the TOPSIS calculates the
most preferred option as the option that is closest to the ideal
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S. Sanon et al. / Journal of Environmental Management 111 (2012) 159e172
positive solution, but also as the option that is furthest away from
the ideal negative solution. Thus, the TOPSIS only suggested the Full
Reconnection option as the most preferred option for the Local
Village, Environmental NGO, National Park Authority and Nature
Protection Administration, who clearly placed highest importance
on the management criteria that scored high under increased
hydraulic connectivity (Fig. 4). The differences in the two rankings
also suggests that the result of an MCDA not only depends on the
standardization technique and calculation of weights, but also on
the choice of decision rules used to aggregate the criteria scores
(Malczewski, 2004). Therefore, it can be more appropriate to use
the structure of a multi criteria decision analysis to guide the
decision making process rather than making a decision based on
the mathematical results (Kiker et al., 2005).
The use of multi criteria decision support tool to assist the tradeoff analysis improved our understanding of how decision makers’
preferences, based on different decision rules, affect the rankings of
the management options. Obviously, it also increases the possibility
to evaluate the performances of a larger decision and criteria space
more efficiently (Pearson and Shim, 1995; Shim et al., 2002). The
advantage becomes more pronounced especially when many
decision makers are being considered as illustrated in our case
study. Multi criteria decision support tool also makes it easier for
planners and decision makers to make use of decision rules that
otherwise would be hard to apprehend mathematically. The next
step would need to be the application of this multi criteria decision
support in a real participatory planning process to see its role in
support of wetland decision making processes. It is expected to
increase the stakeholder’s understanding of how their preferences
affect the floodplain system and how, in turn, that affects other
decision maker’s preferences. We realize the approach is rather
a technical approach (Kakoyannis et al., 2001; Sheppard and
Meitner, 2005) assuming a stepwise planning process. However,
involvement of the stakeholders in the selection and aggregation of
indicators used in the trade-off analysis could increase the validity
of the findings (De Steiguer et al., 2003; Gregory, 2002; Sheppard
and Meitner, 2005). We also realize that the use of multi criteria
decision support tool in a planning and decision making process
might not influence the real decision making as there are other
factors, e.g. economic and political factors, that will influence the
real decision making process as well. However, we think it can play
an important role in the preparation of a participatory decision
making process by acting as an innovative tool to increase the
transparency of gains and losses of different strategies. Hence, the
efficiency of the learning process of complex decision making
problems for both planners and decision makers can be positively
affected.
In conclusion, this research suggests that increased hydraulic
connectivity would benefit the management sectors which
preferred the ecological development of the floodplain habitats.
However, multiple uses including fishery, agriculture and recreation in line with the national park regulations were also achievable
under increased hydraulic surface water connectivity. Further, it
was found that the majority of the involved management sectors
preferred the higher connectivity options as compared to the
Current Status option, which was not preferred by any management sectors. Interestingly the Current Status option was also not
preferred by the Drinking Water Administration, which clearly
preferred the Disconnection option. Therefore, the rankings of the
management options also highlighted the potential conflict
between the ecological development and the drinking water
production. Because of that, it became obvious that, if the higher
connectivity options were to be realized for ecological improvements, then additional measures to secure reliable drinking water
production should be developed and incorporated in the
implementation. This also emphasizes the need to include cost (and
also flood risk) criteria in the decision matrix. The research showed
that pair-wise Pareto trade-off figures provided a useful means to
elaborate and quantify the real trade-offs between wetland functions. The distance based algorithms applied here can also be used
to quantify more than two dimensional trade-offs. Finally, the
research showed that the use of multi criteria decision analyses
should be based on a participatory approach, in which the process
of arriving at the final ranking should be equal or more important
than the outcome of the ranking itself. The next step could be the
use of the method in a wetland decision making process, in which
the stakeholders have to choose between wetland management
options.
Acknowledgements
This work was based on the Optima Lobau research project
(funded by the Austrian Ministry of Science (ProVision 133-113),
the Federal Ministry of Agriculture, Forestry, Environment and
Water Management, the Federal Ministry of Transport, Innovation
and Technology, Municipal Authorities of Vienna, the provincial
government of Lower Austria and the National Park-Authority).
Also, research leading to these results received funding from the
WETwin project implemented under the European Union Seventh
Framework Program (FP7/2007e2013) under grant agreement n
[212300].
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