Influence of land use changes on submarine groundwater discharge

Martí Rufí-Salís,Joan Bach,Joan Rieradevall,Jordi Castillo,Gerard Cantero,Jordi Garcia-Orellana,Almudena Hierro

doi:10.1088/2515-7620/ab1695

Abstract

The 20th century has been characterized by an exponential population growth, with a high density in coastal zones. The aim of this work is to study the impact of land use changes on the hydrological cycle, and possible consequences in marine environment. The study has focused on the relationship between coastal urbanisation and submarine groundwater discharge (SGD) that may cause an alteration in the biogeochemical cycles of marine ecosystems. An analysis of land use changes, historical salinities and nutrients data in the Maresme (Barcelona) coastal zone have revealed that the percentage of urban and forest zone land use has increased since 1990, corresponding to a decrease of nutrients in coastal waters through SGD. These impacts may cause changes in coastal biogeochemical cycles, like the decrease in chlorophyll concentrations. Results denote the correlation between land use, coastal aquifer dynamics and the effects of SGD in coastal environments.

Highlights

Urbanization of coastal areas worldwide has rapidly accelerated during the second part of the 20th and the first decade of the 21st centuries, and is one of the main causes of environmental changes (Grimm et al 2008)
Regarding to the spatial distribution of land uses changes, urban areas tend to be located in the flattest zone of the region, while forests are more likely to be located near the mountain range (Serra de Marina)
Urbanization has triggered changes in the hydrological cycle by altering groundwater recharge through the paving of large surface coastal areas, the abandonment of agricultural areas and an increase of forest cover

Summary

Introduction

Urbanization of coastal areas worldwide has rapidly accelerated during the second part of the 20th and the first decade of the 21st centuries, and is one of the main causes of environmental changes (Grimm et al 2008). This urbanization increase has led to a cascade of environmental changes, as for example, by impacting groundwater resources (Foster 2001, Michael et al 2005). The relationship between land uses changes, characterised by an urban area expansion, and the quality of groundwater resources has been extensively studied (McFarlane 1984, Tellam 1995, Cronin et al 2003, Taniguchi et al 2007). One of the most important characteristics of this urban expansion with respect to coastal aquifer dynamics is the large-scale change in surface permeability, driven by an increase in paved-surfaces. Decreased infiltration can affect both water quality and quantity of aquifers systems, assessed through specific parameters: piezometric levels, conductivity or nutrients concentrations (e.g. nitrates or silicates)

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