Attitudes of political-administrative decision makers towards the implementation of nature-based solutions in water management – a case study on a hypothetical constructed wetland in the Tárcoles River basin

Figures & data

Figure 1. The Tárcoles River basin and the responsibilities of the subcommissions.

Figure 2. Grid used for sorting the 48 statements according to the participants’ individual highest agreement (+5) to highest disagreement (-5), whereby a predefined number of statements could be assigned to the single values.

Table 1. Attributes of the extracted factors (viewpoints) F1, F2 and F3.

	Number of Q-sorts	Eigenvalues	Explained variance
F1	8	4.86	24.31
F2	6	4.18	20.91
F3	3	2.47	12.39

Table 2. Q-set formed by 48 statements (S1-S48), clustered by five categories. The values from −5 (highest disagreement) to 5 (highest agreement) indicate the respective factor scores of a statement.

		F1	F2	F3
Category 1: Engineering
S1	These measures [NBS] instead of technical solutions are of increasing importance in urban water management.	2	0	1
S2	There is a lack of knowledge in urban and landscape planning on how such a measure can be implemented in practice.	2	−2	5
S3	Creating green retention areas should be a main objective of urban planning.	5	2	0
S4	It should always be a case-specific decision whether such a measure [NBS] or a technical treatment is recommended at a site.	1	1	0
S5	Paved ground and roads are a status symbol for urban development of the region.	0	−2	−5
S6	The consequences of such ecosystem-based water treatment measures should be monitored and reviewed regularly.	0	−1	2
S7	No one knows whether the functioning of the constructed wetland will weaken over time.	−1	−3	−2
S8	A high share of sealed surfaces for rapid drainage of rainwater should be aimed for.	−3	−5	−4
S9	Water treatment should be planned & implemented mainly by technical/engineering departments.	−1	2	0
S10	Conventional grey water treatment plants cannot be replaced in their function by the measure shown.	−2	−4	−1
Category 2: Environmental
S11	Constructed wetlands contribute to the resilience of the region to climate change impacts.	4	0	2
S12	The creation of habitat and biodiversity protection are important side effects of such measures [NBS].	5	1	1
S13	An economic valuation of ecosystem services would show that their value exceeds the cost of the measure.	1	−1	4
S14	Environmental protection and restoration have direct positive health effects.	4	1	0
S15	Illegal discharge of sewage into the river is one of the biggest water-related problems.	2	4	1
S16	There are other much more important problems than contamination levels in the river.	−4	−3	−1
S17	We can address environmental protection after we have solved other social problems.	−5	−5	−3
S18	For flood protection, such measures will not help much.	−5	−3	−3
S19	Groundwater contamination through the measure [NBS] poses a risk, especially if residential areas or drinking water sources are nearby.	0	−4	−2
Category 3: Political-institutional
S20	It is problematic that the realization of such a project highly depends on individual views in the city administration.	−1	2	−2
S21	More projects need to be realized in order to improve the database for the evaluation and further development of the methods.	0	1	−1
S22	A paradigm shift in policy towards ecosystem-based approaches is necessary.	1	3	2
S23	It will be difficult to get the area provided by the municipality.	0	0	−4
S24	The implementation of the shown measure [NBS] should be decided at the municipality level.	−2	−1	0
S25	In general, the municipalities in the river basin should cooperate more in decisions that affect the river basin.	4	3	3
S26	Cooperations with educational institutions such as universities are relevant for the planning and implementation of such measures.	0	3	3
S27	Civil society, state institutions and the private sector should be equally involved in planning processes.	0	4	4
S28	Municipalities must not have any additional work resulting from the measure after implementation.	−2	−4	−5
S29	If the measure cannot comply with legal requirements e.g. on land use & road dimensions, it should not be implemented.	−1	0	−4
Category 4: Cost-effort
S30	Municipalities should have more funds available for this type of action.	1	5	−1
S31	Such measures [constructed wetlands] are more cost-effective than technical treatment plants.	−1	−2	1
S32	Private companies should contribute to the financing of the measures.	2	5	2
S33	The financing of such measures [NBS] should be provided by public funds.	−2	−2	−3
S34	The cost to connect the measure to the existing infrastructure could be the biggest economic barrier.	−4	1	−1
S35	A prior risk assessment must be a central part of the measure planning.	3	4	0
S36	Green spaces like these are prone to damage from vandalism.	−1	−1	1
S37	Costs and effort due to maintenance and repair are a disadvantage.	−4	−2	0
Category 5: Citizens
S38	Constructed green spaces have an important social function in cities.	3	2	2
S39	There should be more prototypes to demonstrate the effects to the public and to build trust.	1	−1	−1
S40	There is an appreciation amongst the population for urban green spaces.	3	0	−3
S41	The trust of the residents should not be underestimated.	0	0	−2
S42	Residents must have the opportunity to participate in building the constructed wetland. This also increases acceptance.	1	2	0
S43	All stakeholders must be involved in the planning and implementation phase.	2	3	5
S44	Upstream municipalities bear major responsibility for water quality in downstream municipalities.	3	0	3
S45	It can be difficult to convince the local population of the benefits from the measure.	−2	0	3
S46	Urban vegetation often causes problems (damage by roots, clogging by leaves, etc).	−3	−3	1
S47	Traffic space (pavements, streets, car parks) should not be restricted by these measures.	−3	−1	4
S48	Public places protected from view by, for example, high vegetation will encourage illegal activities such as drug use.	−3	1	−2

Figure 3. Illustration of prioritized categories per factor. Data based on the absolute sum of statement factor scores for each statement category per factor.

Data availability statement

The data that support the findings of this study are available from the corresponding author, BS, upon reasonable request.