Quantitiative DPSIR
Generalities
The DPSIR framework (see Figure 1) (adapted for groundwater sustainability assessments) is summarized as follows (CCME, 2017):
• Driving Force indicators describe the social, demographic and economic developments in societies and the corresponding changes in lifestyles, overall levels of consumption and production patterns.
• Pressure indicators describe the developments by human activities that use groundwater supplies and release contaminants into groundwater.
• State indicators describe the groundwater in terms of physical, biological and chemical phenomena in a certain area.
• Impact indicators that illustrate the effects of changes in the state of groundwater systems.
• Response indicators refer to responses by groups (and individuals) in society, as well as government efforts, to prevent, compensate, ameliorate or adapt to changes in the state of groundwater systems.
The use of DPSIR models in the context of citizen science has been shown to help raise their awareness about the complexity of
groundwater sustainability and improve citizen's understanding of the issues (op. cit.) (Table 1).
1
Application to the Campina de Faro Aquifer system
The domain of analysis comprises the physical space defined by the boundaries of the Campina de Faro aquifer system (Castrillon, 2021). The most important water fluxes across the boundaries are considered, namely the input of tap water and the export of (treated) wastewater.
The assessment of impacts is made quantitatively by using appropriate emission factors to convert pressures (measurable quantities) into impacts (measured as tonnes of COeq) (eqs (1) and (2)).
The model accounts for long-term natural driving forces, such as climate change, in the format of alternative modeling scenarios. The contribution of citizen science is introduced as an objective to help shape better more sustainable management alternatives.
(1)
(2)
The variables are: PL as pressures for the different driving forces (L); emission factors (EFL,i); forcing coefficients (αL,j) (Table 2), which quantify the causal relationships between variables; forcing coefficients between societal responses and pressures or impacts (βL,j) which are “target coefficients” in this study, used to build scenarios of societal response (Table 3).
Emission factors were taken from the Portuguese national inventory report on greenhouse gases, 1990–2017 (APA, 2019).
Conversion of monetary values (Euro) to CO2eq was made by dividing the former by the median value of the European Carbon Allowances for the reference year of 2018 (Figure 2)
Data consisted of time-series for a period of ten years collected from public data repositories.
The Driving forces and associated pressures, states, and predicted impacts are shown in Table 4.
Figure 2. EU Carbon Permits (EUR) trading values (see, e.g.: https://tradingeconomics.com/commodity/carbon
4
Data
Results
For each of the Pressures its Impact was assessed using eq (1). For pressures for which the original unit was Euros, the conversion to CO2eq was done as explained above. Coefficients alpha and betha were set equal to 1 to build a base scenario.
Positive values for the impacts reflect a beneficial consequence (equivalent to the "absorption" of an equivalent amount of CO2eq), and negatives the opposite (emissions of CO2eq).
The sum of the individual impacts per pressure reflects a global appreciation.
The analysis of the summary of impacts (Table 6) shows:
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Revenues from the tourism sector result in the highest positive impacts, about one order of magnitude larger than those of the agriculture; they are followed by conservation values (willingness to pay to preserve the natural ecossystems);
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The highest negative impacts come from the water supply and wastewater treatment (emissions due to pumping and treatment operations), followed by opportunity costs due to contamination of the aquifer by agriculture;
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The costs associated to groundwater pumping (from the use of electricity) are minor when compared to the remaining negative impacts.
The global DPSIR value is highly positive, indicating that, according to the EU emission factors, the region is highly sustainable.
This seems to be the overall appreciation by public entities as reflected by very optimistic prospects of growth for both the touristic and agriculture sectors for the next decade.
We know this evaluation cannot be correct, otherwise, there would be no water stress. However, unless the marginal costs associated to negative impacts become larger relative to their positive counterparts, society will not reduce the Pressures because economic revenues are seen as far superior to the negative impacts...
Table 6 Summary of Impacts
REFERENCES
APA (2019). Portuguese national inventory report on greenhouse gases, 1990 – 2017. Submitted under the artº 5 and 7 of regulation (eu) no. 525/2013 of the european parliament and of the council on the greenhouse gas monitoring mechanism (mmr). Agência Portuguesa do Ambiente, Lisboa.
Castrillón, J. M. (2021). Assessment of the implementation of citizen science in a DPSIR model in the Campina de Faro aquifer system. Master of Science Degree in
Environmental Engineering, Instituto Superior Técnico, Lisboa.
CCME. Groundwater sustainability assessment approach : guidance for application. Canadian Council of Ministers of the Environment, Winnipeg, Canada; 2017.