Application of Combined Geophysical Methods for the Examination of a Water Dam Subsoil

Tomisław Gołębiowski,Bogdan Piwakowski,Antoni Bojarski,Michał Ćwiklik

doi:10.3390/w13212981

Tomisław Gołębiowski, Bogdan Piwakowski + Show 2 more

Open Access

https://doi.org/10.3390/w13212981

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Journal: Water	Publication Date: Oct 22, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: Cracow University of Technology, École Centrale de Lille

Abstract

The paper presents the results of geophysical measurements that were carried out in the vicinity of the water dam/water reservoir supplying the city of Bielsko-Biala with drinking water. The measurements were performed in order to non-invasively detect faults, fractured zones and areas filled with breccia, which may be, at the same time, a preferential path of groundwater flow. The aforementioned factors influence the stability of the dam. The general identification of the examined media was realized by the electrical resistivity tomography method. The ERT surveys were supplemented by capacitively-coupled resistivity. The electrical methods allowed them to recognize geological settings, indicate possible fault locations, and point out the fault plane as a path of water flow. The ground penetrating radar method detected fractured and filled water areas and underground water paths in the dam’s forefield as a result of the method’s very high resolution. The high resolution seismic reflection method provided a clear and high resolution image of the relatively deep geological structure and verified a location and the run of the faults. In general, the complex geophysical-geological interpretation enabled classification of the unconsolidated/fractured zones associated with faults as a place where the erosion process is the most intense and can bring danger on the dam. Finally, it was confirmed that the area should be the subject of geophysical monitoring.

Highlights

Hydro engineering constructions are crucial for protecting human lives and activities.Regrettably, the technical condition of this type of construction in many countries is not satisfactory
As mentioned in the introduction, the geophysical methods were applied for noninvasive detection of faults, fractured zones and areas filled with breccia in the subsoil of the water dam
The short-offset reflection surveys were carried out along the profiles Ground Penetrating Radar (GPR)-1 and GPR-2 (Figure 2), they were preceded by the WARR measurements performed along the 10-m-long profiles named: GPR-WARR-1 . . . GPR-WARR-10, designed alongside profile GPR-2 (Figure 2)

Summary

Introduction

Hydro engineering constructions are crucial for protecting human lives and activities.Regrettably, the technical condition of this type of construction in many countries is not satisfactory. The water dam is almost 100 years old and was built in an area with a complex geological structure (Carpathian flysch) [2,3,4]. The dam construction is at risk, as evidenced by the constantly appearing new cracks and changing levels in piezometers (during the measurements session the water level decreasing). Recently (August 2021) the water level in the piezometers has been increasing and the phenomena is correlated with the rainwater afflux from the nearby mountains. These factors show how the hydrogeological situation is complex. In our research we perform a general geological recognition with the use of noninvasive geophysical methods.

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