Functional Responses Of Groundwater ecosystems to managed aquifer recharge in urban areas

Informations

Funding country

France

Acronym

FROG

URL

-

Start date

1/1/2016

End date

-

Budget

620,688 EUR

Fundings

Abstract

Modern societies increasingly rely on goods and services provided by subterranean ecosystems for their well-being and development. Ground water is increasingly being extracted for drinking water supply to accommodate the world population growth and surface water pollution. Alternative water management practices such as the intentional stormwater infiltration developed in urban areas can increase groundwater recharge. However, the environmental efficacies of such kind of managed aquifer recharge (MAR) practices rely exclusively on the self-purification capacity of soils and aquifers. Although the performance of MAR systems to prevent groundwater contaminations by hydrocarbons and heavy metals has been demonstrated, it is not the case for chemicals like pesticides/biocides and microbes including bacterial pathogens. Moreover, MAR practices generate major physical (temperature fluctuations) and chemical (oxygen content decrease) disturbances for groundwater ecosystems. Nevertheless, studies on the functional response of groundwater ecosystems to these disturbances are lacking. What is the resistance and resilience of these ecosystems to disturbances? Are groundwater microbial communities that play key roles in water purification processes vulnerable to these disturbances? The present project aims to fill these gaps through field and laboratory experimental approaches. Research will be developed along four closely related tasks. The workpackage (WP) 1 will be partly devoted to the development of sampling tools based on integrative samplers to evaluate groundwater microbial diversity but also the transfer of bacterial and chemical contaminants from surface water to groundwater in MAR systems (Actions 1.1 and 1.2). The WP 2 will focus on the hydrogeological modelling of the water transfer in 6 MAR systems presenting contrasted physical characteristics (vadose zone thickness, hydraulic conductivity of the infiltration bed of the basin,…) (Action 2.1) and the coupling of this modelling approach with chemical and biological contaminant transfers during three stormwater events (Action 2.2). Such coupling will allow a precise description of the plume of stormwater in groundwater, its potential impact on water quality, and the contribution of MAR system characteristics to contaminant transfers. The WP 3 will quantify the functional responses of local groundwater microbial communities to disturbances associated with MAR practices. Based on a coupling of field (Action 3.1) and laboratory (Action 3.2) works, the structural and functional resistance and resilience of groundwater microbial communities will be assessed during disturbances generated by stormwater events. The results of the project will contribute to the definition of recommendations for stormwater infiltration device design and for operational monitoring systems. WP 4 focuses exclusively on the transfer of scientific research to the management of stormwater infiltration in urban areas. All these tasks will contribute to increase our knowledge on the functioning of groundwater ecosystems and their responses and vulnerabilities to urban-impacted conditions. Development of integrative samplers is a crucial initiative to evaluate the occurrence of chemical and biological contaminants present at low concentrations in groundwater. It will allow the first quantification of MAR system performances on groundwater quality. Our project also has the ambition to develop functional indicators of groundwater ecosystem health intended for water managers.