As the climate is changing, greater exploitation of groundwater reserves is becoming evident; however, this would have been apparent even without climate change. Therefore, increasing emphasis is given to maintaining well functionality. Wells are susceptible to aging, which reduces their efficiency. Today, there exist several solutions for determining the size of additional resistance (the skin effect), which indicates a well’s current state and that of its close surroundings. The implementation of most of these solutions is often time-consuming. To improve our tools, a goal has been set to accelerate and facilitate the method of determining the size of additional resistance. In this study, we present new software that accelerates this process. It applies an innovative method based upon a partial differential equation describing the radially symmetric flow to a real well, which occurs under an unsteady regime, using the Laplace transform. Stehfest algorithm 368 is used to invert the Laplace transform. Such software can be used to evaluate an additional-resistance well, even when a straight section evaluated using the Cooper–Jacob method is not achieved in the semilogarithmic plot of drawdown vs. log time during the pumping test. This solution is demonstrated in the comprehensive evaluation of 10 wells and 3 synthetic pumping tests.

The exploitation of groundwater reserves, especially for drinking purposes, is becoming increasingly important. This fact has created the need to maintain wells in the best possible functional condition. However, wells are subject to an ageing process during intensive use, which entails an increase in up-to-date resistances in the well itself and its immediate surroundings (the skin zone). This causes a decrease in the efficiency of the well (a decrease in the pumped quantity, a decrease in the specific yield, an increase of the drawdown in the well, and creation of the skin zone). The increased hydraulic gradient in the skin zone causes an increase in the inflow rate to the well, thereby inducing the movement of fine material towards the casing. This material can clog the well casing and injection ports, which is compounded by an increase in chemical and biological plugging of the skin zone. In cooperation with the company sonic technologies, GmbH. (Sailauf, Germany), an experimental ultrasonic technology-based well rehabilitation assembly was developed and successfully tested. This article describes the prototype development of the ultrasonic device, including its incorporation into the rehabilitation set and a demonstration of its pilot deployment in the MO-4 pumping well in Czech Republic with an evaluation of the rehabilitation effects using the authors’ software (Dtest_ULTRA). Based on visual inspection and the results of hydraulic and geophysical analysis, the high efficiency of the tested technology was demonstrated in virtually all monitored parameters, where an improvement in the range of 25–55% compared to the original condition was identified.

The declining supply of available groundwater resources is increasing the importance of extraction wells. To maximize the yield of extraction wells, the operators do not always respect the sustainable use of groundwater resources. These efforts can affect water quality and impact the service life of an extraction well, mainly through the clogging process. As part of the INV-FLOW project, an apparatus for evaluating the functionality of an extraction well by measuring the vertical water flow through its screen and filter was designed and tested. The apparatus consists of two electromagnetic induction flowmeters, two pneumatic seals, and a pump with the possibility of regulation. After an initial laboratory verification of the fundamental concept, the apparatus was successfully tested in real conditions. Two extraction wells, HJ-3 and HJ-4, intended for water supply to an agricultural production plant, were measured at a pilot site in the Czech Republic using the INV-FLOW apparatus. Although the HJ-3 extraction well is at the end of its service life, the HJ-4 extraction well is a newly installed well. In the new extraction well, HJ-4, a high proportion of water flowing through the gravel pack relative to the total pumping flow (93–97%) was measured using the INV-FLOW apparatus at different pumping rates. In the case of the HJ-3 extraction well, screen and filter clogging contributed significantly to the limited water flow through the gravel pack. In the most affected parts of the extraction well (15–20 m b.g.l.), the proportion of water flowing through the gravel pack relative to the total pumping flow ranged from 10 to 20%. The pilot tests confirmed the functionality of the apparatus and the possibility of using it to evaluate the degree of clogging and incrustation of an extraction well. The pilot tests thus demonstrated the usability of the INV-FLOW apparatus. The extraction well operator can assess the level of clogging or incrustation of the extraction well and decide on the need for the rehabilitation of an extraction well, or the termination of its operation.