A Model for the Assessment of the Water Footprint …
97
The indicator has been used since its inception to determine the impact of the agricultural sector but can be also useful to assess the urbanization. This methodology,
adapted to the unique characteristics of the construction sector, has been chosen for
its comprehensibility, transparency, and adaptability.
5 Conclusions
The indirect WF of the scenarios that apply a water-sensitive urban design (S2 and
S3) is 1.7 times greater than the scenario in which only the water supply and sanitation facilities are renewed and the street is restored to its original state (S1). Local
rainwater management in scenarios S2 and S3 improves the direct WF of S1 by 82%
per year. This saving at the end of the life cycle accumulates 66% less footprint,
it is in year 4, when these projects accumulate a total WF of 5.00 m
3 /m
2 and are
equal in water consumption, and therefore, the amortization in terms of water of the
infrastructures is produced.
The incorporation of SUDS has made it possible to reduce the volume of peak rainfall relieved from the sewage network by 78% in its area, leading to energy savings by
reducing the volume of pumping and wastewater treatment that the municipal system
should treat. Including infrastructures that take advantage of rainwater for irrigation,
in addition to offering better management of urban runoff, reducing the overloading
of sewage networks and the dragging of pollutants, allows alternative water resources
to be available by being able to recirculate around 362 m
2 of rainwater, for the conservation of green spaces, and therefore, less dependence on general supply systems.
The use of high-efficiency irrigation systems is confirmed as a water-saving measure.
The incorporation of green areas and irrigation infrastructures, the incorporation
of plants with a lower water demand or native plants (S2), as opposed to those with
a higher water demand or ornamental plants (S3), although the general balance is
similar, the difference in the green WF is higher in ornamental plants, and therefore,
represent an improvement in the biophysical environment; ornamental plants require
more irrigation and the blue component increases, even despite the use that the system
makes thanks to the reuse of rainwater; on the other hand, native plants, as they do not
make use of rainwater, the grey component is higher, hence in both cases the balance
is similar. An optimal scenario would be an urban garden where areas are distributed
with plants with different water requirements that consume rainwater in an optimal
way, minimize the demand for irrigation water and tend to zero the unused water.
6 Future Lines of Research
To implement the calculation of indirect WF as an environmental criterion for evaluating offers within public procurement processes. In the construction sector, the
public sector has a prominent role in the path towards a more sustainable production
97
The indicator has been used since its inception to determine the impact of the agricultural sector but can be also useful to assess the urbanization. This methodology,
adapted to the unique characteristics of the construction sector, has been chosen for
its comprehensibility, transparency, and adaptability.
5 Conclusions
The indirect WF of the scenarios that apply a water-sensitive urban design (S2 and
S3) is 1.7 times greater than the scenario in which only the water supply and sanitation facilities are renewed and the street is restored to its original state (S1). Local
rainwater management in scenarios S2 and S3 improves the direct WF of S1 by 82%
per year. This saving at the end of the life cycle accumulates 66% less footprint,
it is in year 4, when these projects accumulate a total WF of 5.00 m
3 /m
2 and are
equal in water consumption, and therefore, the amortization in terms of water of the
infrastructures is produced.
The incorporation of SUDS has made it possible to reduce the volume of peak rainfall relieved from the sewage network by 78% in its area, leading to energy savings by
reducing the volume of pumping and wastewater treatment that the municipal system
should treat. Including infrastructures that take advantage of rainwater for irrigation,
in addition to offering better management of urban runoff, reducing the overloading
of sewage networks and the dragging of pollutants, allows alternative water resources
to be available by being able to recirculate around 362 m
2 of rainwater, for the conservation of green spaces, and therefore, less dependence on general supply systems.
The use of high-efficiency irrigation systems is confirmed as a water-saving measure.
The incorporation of green areas and irrigation infrastructures, the incorporation
of plants with a lower water demand or native plants (S2), as opposed to those with
a higher water demand or ornamental plants (S3), although the general balance is
similar, the difference in the green WF is higher in ornamental plants, and therefore,
represent an improvement in the biophysical environment; ornamental plants require
more irrigation and the blue component increases, even despite the use that the system
makes thanks to the reuse of rainwater; on the other hand, native plants, as they do not
make use of rainwater, the grey component is higher, hence in both cases the balance
is similar. An optimal scenario would be an urban garden where areas are distributed
with plants with different water requirements that consume rainwater in an optimal
way, minimize the demand for irrigation water and tend to zero the unused water.
6 Future Lines of Research
To implement the calculation of indirect WF as an environmental criterion for evaluating offers within public procurement processes. In the construction sector, the
public sector has a prominent role in the path towards a more sustainable production