Urban water quality issues are present in cities around the world (McDonald et al., 2011). Pollution sources in urban areas are diverse. They include industry, traffic, construction, domestic discharges, upstream pollution or deposition. Also the types of contaminants from these sources cover a large diversity, including nutrients, heavy metals, pathogens or organic pollutants (Strokal et al., 2021). As a result, the urban surface (and ground-) water that is available for ecosystems and human use degrades in quality and might not meet the requirements necessary for the different purposes. When calculating (urban) water balances, usually only water quantity is taken into account, see e.g. Flörke et al. (2018). But to comprehensively assess if supply can meet the demand, also water quality needs to be included into a water balance. Moreover, including water quality in urban water balances will provide insights to smarter water allocation strategies, especially during times where not sufficient water is available.
Objective
The objective is to conceptualize a generic water quality balance for cities and apply that concept to conduct a case-specific water balance for one city/district/neighbourhood.
Method
- Conceptualizing a water quality balance for cities
- Identify common pollution sources in cities (from literature)
- Identify common pollutants per source (from literature)
- Identify common water uses (human and ecological) (from literature, e.g. Haase (2015), van der Meulen et al. (2020))
- Define water quality thresholds for different urban water uses (see e.g. the water framework directive, van der Meulen et al. (2022))
- Selecting a case study
- Applying the water quality balance concept to conduct a water quality balance
- For the selected case, conduct a water quality balance. Depending on the extend, this can focus on selected (most relevant) pollutants or pollution sources
- Calculating/modelling water supplies and demands with respective qualities at an adequate temporal resolution. For the supply, public and scientific data should be used. For the demand, different stakeholders might have to be interviewed. This should be combined with literature on ecologic and human water quality requirements.
Expected results
- A generic concept to conduct a water quality balance for cities
- A water quality balance for a specific city
References
- Flörke, M., Schneider, C. & Mcdonald, R. I. 2018. Water competition between cities and agriculture driven by climate change and urban growth. Nature Sustainability, 1, 51-58, 10.1038/s41893-017-0006-8.
- Haase, D. 2015. Reflections about blue ecosystem services in cities. Sustainability of Water Quality and Ecology, 5, 77-83, https://doi.org/10.1016/j.swaqe.2015.02.003.
- Mcdonald, R. I., Douglas, I., Revenga, C., Hale, R., Grimm, N., Grönwall, J. & Fekete, B. 2011. Global Urban Growth and the Geography of Water Availability, Quality, and Delivery. AMBIO, 40, 437-446, 10.1007/s13280-011-0152-6.
- Strokal, M., Bai, Z., Franssen, W., Hofstra, N., Koelmans, A. A., Ludwig, F., Ma, L., Van Puijenbroek, P., Spanier, J. E., Vermeulen, L. C., et al. 2021. Urbanization: an increasing source of multiple pollutants to rivers in the 21st century. npj Urban Sustainability, 1, 24, 10.1038/s42949-021-00026-w.
- Van Der Meulen, E. S., Sutton, N. B., Van De Ven, F. H. M., Van Oel, P. R. & Rijnaarts, H. H. M. 2020. Trends in Demand of Urban Surface Water Extractions and in Situ Use Functions. Water Resources Management, 34, 4943-4958, 10.1007/s11269-020-02700-7.
- Van Der Meulen, E. S., Van Oel, P. R., Rijnaarts, H. H. M., Sutton, N. B. & Van De Ven, F. H. M. 2022. Suitability indices for assessing functional quality of urban surface water. City and Environment Interactions, 13, 100079, https://doi.org/10.1016/j.cacint.2022.100079.
Supervision
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