Kurikka Aquifer Project 9

Introduction

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 ninth phase of deep groundwater surveys started in the summer of 2022. The main goal for the project is characterizing the groundwater behaviour and quality in the bedrock fracture systems. It is obvious that bedrock fractures play a significant role in the Kurikka groundwater system carrying groundwater in the connection with sediment. Also find out the groundwater budget in the Kurikka region with the precision required for water supply planning are highlighted.

The Kurikka Aquifer project has now reached the point where extensive geological surveys will be completed in the end of the 2022. Also the remaining production wells are built and test pumped by the end of the 2023. During the groundwater test pumping program additional observation wells will be monitored for the environmental impact of the test pumping. The test pumping conducted at phases 2 to 4, together with high volume pumping results and geological 3D models, form the basis for modelling the hydrological cycle, water budget and the groundwater potential 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.

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