Groundwater vulnerability assessment and protection measures - An example from Sweden

Abstract

The purpose of this study is to highlight the importance of groundwater vulnerability assessment and the need for groundwater protection measures. An example is taken from the Tanum Municipal area in Sweden and a case study was conducted with the available data on boreholes, water levels and chemical analysis. The case study included fieldwork on the site, observation of lineaments and aerial photographs, land use maps, drainage patterns and bedrock characteristics. The private owners in general do not site boreholes according to the scientific investigations resulting in low yield for the boreholes on average. The indiscriminate drilling of wells close to the coast induces seawater intrusion. Groundwater quality of the boreholes for the parameters such as pH, Chloride, Magnesium, Potassium, total hardness, Nitrate and Fluoride were analysed. The results showed that the poor groundwater quality in most of the boreholes is due to poor well construction and indiscriminate construction of wells close to contaminant sources without knowing the hydro geological background of the study area. A classification system was used based on the characteristics of lineaments and the other aquifer parameters. Then aquifer vulnerability classes and the protection zones were derived based on the results. It was revealed that the area was vulnerable and therefore, protection and legislative measures are important to control further deterioration of the groundwater resources. This study would be useful in developing of the vulnerability zones and protection zones for groundwater.