Kurikka Aquifer Project 8

Introduction

KURIKKA AQUIFER PROJECT

The Geological Survey of Finland continues its groundwater research in the Kurikka region in cooperation with Vaasan Vesi, Kurikan Vesihuolto Oy and the Southern Ostrobothnia ELY Centre. The ambitious aim of the research is to find enough groundwater in the Kurikka region to meet the demands of 150,000 people and the large food industries in the Vaasa and Kurikka regions.

Groundwater surveys (for GTK’s part) started some ten years ago, when hydrogeological surveys were carried out in the groundwater area of Aronlähde and Kuusistonloukko. At that time, very thick sand and gravel inter till layers located in a bedrock depression were found by deep drilling. This brought up the possibilities for larger scale water abstraction in the Kurikka region, and thus the City of Vaasa also became interested in Kurikka’s potential for deep groundwater.

The sediment cover in Kurikka is exceptionally thick and complex in structure, and the fragmented bedrock surface of the area contributes to the significance of the groundwater body. Groundwater is recharged in wide highland areas to flow aquifers that are located at lower elevations and the quality of (deep) groundwater has also proven to be good. In addition, the groundwater in the area is well protected under thick clay deposits.

After finding the Kurikka buried valley aquifer, Kurikka’s deep groundwater bodies have been surveyed in several separate projects since 2014 and the eighth phase of deep groundwater surveys started in the summer of 2020. However, the groundwater surveys will continue for several more years and many more steps are required to find out the hydrology and hydrogeology of deep groundwater in the Kurikka region with the precision required for water supply planning.

The Kurikka Aquifer project has now reached the point where extensive groundwater body surveys were completed in late 2020 to start again in summer of 2021. Currently, the focus of the work is shifting towards various types of modelling. Phase 8 of the project focuses on the development of a 3D model of the bedrock fracture systems in the area, groundwater surface visualization and activities supporting groundwater flow modelling. Sediments 3D modelling will also be continued based on new research results. At the same time, efforts will be made to classify different aquifers’ waters based on their chemical composition.

In the summer of 2021, the remaining production wells will be built and test pumped by the end of the year. Together with the pumping tests, additional observation wells will be constructed to monitor the environmental impact of the test pumping. The test pumping conducted at phases 2 to 4, together with this project pumping results and geological 3D models, form the basis for modelling the hydrological cycle of the entire research area. The ultimate goal of the research unit is to obtain sufficient background information both for the licensing EIA process for water abstraction. The goal is to route groundwater from Kurikka towards Vaasa in 2030.

The project is financed by Vaasan Vesi, Kurikan Vesihuolto Oy, South Ostrobothnia ELY Centre and GTK.

Return to projects