DBPapers
DOI: 10.5593/sgem2017/12/S02.085

PUMPING TEST FOR GROUNDWATER AQUIFERS IN URBAN AREA BUCHAREST CASE STUDY

N. Calin, I. Bica
Sunday 10 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7105-99-5 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 12, 669-678 pp, DOI: 10.5593/sgem2017/12/S02.085

ABSTRACT

The sedimentary environments are in general very important aquifers because of the following characteristics: high permeabilities, storage capacity, the interaction with the surface waters. The exploitaition of this types of aquifers it is significant because, among other things, this aquifers are easily accessible (in general we don’t need complex systems of capture and in most cases are enough wells ans/or drilling between 10-100m depth). Must of the aquifers structures from the south part of Romania are usually, under pressure or with free surface.The ground is composed by horizontal strata of different permeability.
Principal part in many projects and studies dealing with groundwater exploitation, protection and remediation.
The pumping test is one of the most useful tools available in the evoluation groundwater producing formations.
Pumping tests are an important part of any groundwater investigation or groundwater scheme feasibility study. They provide essential information which can affect the planning and build of a project and often required to allow an application of an abstraction license for water supply wells and open-loop ground source energy systems.
Pumping test gives the best information on the drawdown level, flow rates and unforeseen factors generated upon pumping.
There are two main objectives of pumping tests:
▪ A pumping test may be performed in order to determine the hydraulic characteristic of aquifers or water bearing layers. Such a test is often called an aquifer test because it is the aquifer rather than the pump or well which is tested. Properly planned and carefully conducted ‘aquifer-test’ may provide basic information for the solution of many regional as well as local ground water flow problems;
▪ A pumping test may provide information about the yield and drawdown of the well. These data can be used for determining the specific capacity or the discharge drawdown ratio of the well, for selecting the type of the pump and for estimating the cost of pumping. The specific capacity gives a measure of the effectiveness or productive capacity of the well. Such a pumping test is sometimes called a ‘well-test’ because it is the well, rather then the aquifer, which is tested.
The principle of a pumping test involves applying a stress to an aquifer by extracting groundwater from a pumping well and measuring the aquifer response to that stress by monitoring drawdown as a function of time.
These measurements are then incorporated into an appropriate well-flow equation to calculate the hydraulic parameters of the aquifers.
The experimental pumping follow the establishment of relationships between the pumped debits and drawdown recorded in the central drilling and in the observation one, relations wich allow the determination of the hydrogeological parameters of the aquifers layers.
The hydrogeological parameters wich can be calculated with the measures data during experimental pumping are:
o Hydraulic conductivity: k (m/zi);
o Transmissivity: T (m2/zi);
o Radius of influence: R (m).
The paper present a case study from Bucharest City related to pumping test.

Keywords: pumping test, groundwater, drawdown, hydraulic parameters.