Pumping tests

Pumping tests as field research provide the following information:

• filtration parameters of the aquifer are calculated
• scheme of the aquifer recharge is studied
• conclusions determining groundwater resources are formulated

Due to their importance, as well as costs, they must be well thought undertakings, giving specific research and economic effects.

Pumping tests are commonly used in the hydrogeological practice. There is almost no hydrogeological region (except mountain areas) where this type of research would not be conducted.

What are the pumping tests:

Basic aim of the pumping test is to obtain (by water intake from a well - piezometer) the hydrodynamic response of the aquifer, which allows to specify the filter parameters of the layer, well-operation parameters and conditions of recharge. An equally important task during the pumping test is groundwater sampling from the activated zone of the inflow into the test borehole. The water is subjected to the physico-chemical and bacteriological laboratory analysis and to the technological analysis in the case of groundwater intakes, due to the need of determining the technical conditions of the water treatment. The entire hydrodynamic and hydrochemical tests conducted during the pumping tests are to determine the quantity and quality of the groundwater.

The following research aims with increasing degree of their complexity can be realized through the pumping tests:

• determination of the characteristics in terms of well - aquifer interaction
• examination of the well in terms of its future operating equipment and rational exploitation,
• field measurements of the hydrodynamic parameters of the aquifer (hydraulic conductivity, coefficient of permeability, coefficient of gravity or elastic gravitational drainage capacity)
• quantitative assessment of the specific characteristics of the aquifer, as: infiltration of water from adjacent layers, boundary conditions, diversity of aquifer sediments, etc.
• direct observations of the effects of water extraction from the aquifer, including the identification of the development of the drawdown, depending on the flow rate of the well and determination of the size of admissible volume of extracted groundwater including their quality parameters
• well and intakes interaction

Part of these aims can be achieved only by a hydrogeological pumping nodes containing - in addition to the pumped well - at least one piezometer.

Types of the pumping tests:

Individual pumping is carried out in a single test borehole to identify the relation between the discharge and the drawdown, which allows to determine the hydraulic characteristics of the water intake and approximate hydrogeological parameters of the aquifer in the vicinity of the borehole. Pumping well with observation wells is carried out in a single test borehole or, in certain cases in the group of boreholes located close together while watching the water level in the observation wells.

Collective pumping is carried out with more test boreholes, which are intended for use as a future intake wells to the experimental verification of the discharge and the amount of the drawdown in terms of usable operation of this intake and to determine the components of recharge of its admissible volume.

Selection of the type of the pumping is associated with the intended documentary project and the complexity of the hydrogeological conditions.