Water accounting for stressed river basins based on water resources management models

Abstract

A comprehensive study aimed at evaluating the occurrence, significance of concentrations and spatial distribution of priority pollutants (PPs) along the Comunidad Valenciana coastal waters (Spain) was carried out in order to fulfil the European Water Framework Directive (WFD). Additionally, PPs concentrations were also analysed in the effluent of 28 WWTPs distributed along the studied area, since these infrastructures are usually considered a significant point source of many of these toxic substances.In coastal waters 36 organic pollutants of the 71 analysed, including 26 PPs (8 of them priority hazardous substances) were detected although many of them with low frequency of occurrence. Only 13 compounds, which belong to four different classes (VOCs, organochlorinated pesticides, phthalates and tributyltin compounds (TBT)) showed a frequency of occurrence above 20% in coastal waters. Toluene was the most ubiquitous pollutant (detected in 100% of the samples) with maximum concentration of 1.6 g/l. All analysed coastal waters showed the presence of PPs, being di(2-ethylhexyl)phthalate (DEHP) the most frequent one (detected in 57% of the samples) reaching concentrations up to 15 g/l. In the results obtained until now, there are four compounds that exceed the established Environmental Quality Standards (EQS): octylphenol, pentachlorobenzene, DEHP and TBT exceeded the annual average concentration (EQS-AAC), and only TBT surpassed the maximum allowable concentration (EQS-MAC).Despite its prohibition, endosulfan and hexachlorocyclohexane (HCH) were detected in 9% and 30% of the samples, respectively, and their concentrations were relatively close to their EQS-AAC value (around the 70 %). The most frequent contaminants determined in coastal waters were also present in WWTP's effluents. Generally, effluents from WWTPs exhibited higher frequency of occurrence and concentration than in coastal waters, except for DEPH.

Assessment of Ecosystem Services and Water Accounting Methodologies for Integrated Water Resources Management in water scarce basins.

“…Later, it was adopted by the This WA framework was initially designed to be implemented annually at national scale; some examples are the applications in Australia (Vardon et al, 2007) and China . However, its utilization at river basin scale has turned to be more relevant with many examples such as the PedroMonzonís et al, 2016a;Pedro-Monzonís et al, 2016b; Vicente et al, 2016).…”

“…This is crucial in water scarce river basins where the state of water reserves determines the activation of additional resources to assure the water supply (Pedro-Monzonís et al, 2016b). Nonetheless, none of them is able to represent water flows between the same type of water resources (surface or groundwater).…”

“…The assessment of the economic benefits of water use by means of hydro-economic models has also been widely studied as a way to contribute to IWRM . Other methodologies have just recently been analysed on this regard, such as ES (Liu et al, 2013) and WA (Pedro-Monzonís et al, 2016b).…”

“…The assessment of the economic benefits of water use by means of hydro-economic models has also been widely studied as a way to contribute to IWRM . Other methodologies have just recently been analysed on this regard, such as ES (Liu et al, 2013) and WA (Pedro-Monzonís et al, 2016b).Nonetheless, casuistry across European waters is very diverse (European Commission, 2012a), and key issues for IWRM are not common to all regions.Neither are the preexisting legal regulations and water management practices. For example, as highlighted in Section 1.1., the complexity and Assessment of Ecosystem Services and Water Accounting Methodologies for Integrated Water Resources Management in water scarce basins 12 specific features that water management in scarce river basins entails is an added difficulty for the implementation of IWRM.…”

“…Later, it was adopted by the This WA framework was initially designed to be implemented annually at national scale; some examples are the applications in Australia (Vardon et al, 2007) and China . However, its utilization at river basin scale has turned to be more relevant with many examples such as the PedroMonzonís et al, 2016a;Pedro-Monzonís et al, 2016b; Vicente et al, 2016).The hydrological models are useful to obtain water stocks and flows related to the water soil balance and surface-groundwater relationships, while the water allocation models allow filling out the water supply and use items as well as testing different management scenarios to be compared through the water accounts. Using models also provides results at a finest time scale and, thus the application cases are implemented at monthly or seasonal scale rather than annual.…”