Gaussian simulation of nitrate concentration distribution in the Zagreb aquifer

Zoran Kovač,Marko Cvetković,Jelena Parlov

doi:10.1080/17445647.2017.1354786

Abstract

ABSTRACTNitrates present one of the most common groundwater contaminants in the world and one of the five major groups of contaminants in the study area. Gaussian simulation (GS) algorithm was used for determining the spatial distribution of average nitrate concentrations from 2010 to 2015 on 95 sampling points. Results indicate two main focus areas of nitrate contamination, located on the left and right bank of the Sava River. Those areas generally extend according to groundwater flow, while areas near Sava River have much smaller concentrations. GS showed that they can be useful for this kind of mapping because they favor abrupt changes in data values which are in this case a result of heterogeneous lithological composition of the aquifer.

Highlights

Nitrate contamination presents one of the most common groundwater quality problems in the world (Almasri, 2007; Peña-Haro, Pulido-Velazquez, & Sahuquillo, 2009) and in the Croatia (Larva, Marković, & Brkić, 2010; Nakić et al, 2013)
Local variations in characteristics of unsaturated and saturated zones have a large impact on the nitrate concentration in groundwater
Two main focus areas of nitrates contamination in Zagreb aquifer can be observed (Main Map), one in the dominantly urban area located on the left bank of the Sava River, and the other on the right bank, in a dominantly agricultural area

Summary

Introduction

Nitrate contamination presents one of the most common groundwater quality problems in the world (Almasri, 2007; Peña-Haro, Pulido-Velazquez, & Sahuquillo, 2009) and in the Croatia (Larva, Marković, & Brkić, 2010; Nakić et al, 2013). Almasri (2003, 2007) noted that nitrate leaching from unsaturated zone presents consequence of complex interaction between on-ground nitrogen loading, land use, nitrogen dynamics, soil characteristics, recharge and depth to groundwater table. Lake et al (2003) determined surface leaching, soil characteristics, drift cover and aquifer type as four main groups of parameters that have influence on groundwater vulnerability to nitrate pollution. In groundwater, they mostly depend on transport (e.g. advection, dispersion and diffusion) and geochemical (e.g. denitrification) processes, and on aerobic and anaerobic conditions in unsaturated and saturated zones.

Research area

Data and methods

Conclusions