Design, installation and permitting of pumping wells
A groundwater well provides continuous access to a good quality water supply. Thanks to the many years of experience, AGT has the tools and expertise to prospect new locations for pumping wells. We work with different drilling companies on a daily basis, which gives us a good idea about the quality and prices for drilling. AGT can provide implementation of groundwater wells from start to finish with a quality guarantee.
Advice on groundwater well installation by AGT
AGT can support you with:
- Investigation of the available aquifers and potential yields;
- Design of the well installation with detailed specs;
- Selection of the drilling company in consultation with the customer;
- Follow-up of the drillings and description of the soil layers;
- Choice of the filter screen and filter pack based on the drill log and sieve analysis;
- Proper development of the well;
- Testing of the well capacity and the water quality.
Pumping of high-quality water with a sufficient flow rate strongly depends on the correct installation of the well. A wrongly placed well often leads to a low flow rate or a high content of fines in the pumped water. The correct characterisation of the local hydrogeology determines the allocation of the wells onsite, the drilling technique, drilling diameter, filter screen depth, slot width, the gravel pack and clay seals, the pump capacity and the pipework. Furthermore, thorough development (cleaning) of the well is essential to produce a high yield of clear water.
Permitting of groundwater wells
Governments follow a strict policy to prevent excessive exploitation of aquifers by giving selective permits. Groundwater abstraction can, after all, cause depletion of aquifers, lowering of the water table, attraction of saline water, displacement of contamination or terrain subsidence. Typically, the flow rate and potential environmental impacts will determine the permitting requirements. In some cases, an Environmental Impact Assessment (EIA) is necessary. The permit often requires a hydrogeological study and a monitoring plan of the groundwater levels and flow rates.
AGT can contact the permitting authority for you to evaluate the feasibility of the application. If the permitting authority gives a positive signal, the permit can be prepared underpinned by a hydrogeological study. With the help of a numerical groundwater model, the influence radius of the water abstraction is simulated and the long-term effects are determined.
New or existing groundwater wells?
Do you want to install a new pumping well or do you want to increase or decrease the capacity of your existing well(s)? Do you wonder how to tackle this project?
Contact us and let's work together!
Pumping tests are carried out in order to determine the hydrogeological parameters of the substrate. With a step-drawdown test the well efficiency can be determined, while with a constant-rate test, the transmissivity of the aquifer can be determined. Injection tests helps to determine how much groundwater can be injected. The groundwater levels are continuously measured during these tests by online, automatic pressure sensors.
Analysis of a pumping test
The performed pumping test is afterwards analysed to estimate the hydrogeological parameters of the aquifer and to determine the well efficiency. The parameter estimation can be done with analytic formulas, with the semi-analytic code MLU (Multi-Layered Unsteady State) or with a numerical groundwater model.
Inspection and rehabilitation of an existing water well
The efficiency of a groundwater well can significantly decrease without any obvious reason. AGT has in-house borehole geophysical logging equipment and a borehole camera which allow us to carry out well inspections at very short notice. Once correctly diagnosed, the well can be rehabilitated by repairing the filter, chemical treatment with specialized products and /or redevelopment of the well.
New or existing groundwater wells?
Decreased flow rate, pumping of sand, rust on the well head, subsidence of the soil around a well ... just like a sick patient, the same applies to ‘sick’ wells: prevention is easier than trying to cure!
AGT has many years of experience as a "well doctor" to repair problematic wells.
The vulnerability of groundwater depends on the nature of the aquifer, the cover layers, the unsaturated zone as well as the possible pollutants and their hydrogeochemical properties. AGT has the necessary expertise to perform a detailed vulnerability analysis so that an efficient groundwater monitoring strategy can be worked out and the effects of water extraction on the groundwater quality can be better estimated. The potential contaminant spreading can be estimated by means of numerical groundwater modelling coupled to mass transport.
In order to monitor the effect of groundwater abstraction on the environment, the government often requires the monitoring of groundwater levels in monitoring wells. In the past, groundwater levels were measured manually with a tape meter in the well, which is time-consuming. Nowadays, automatic water pressure sensors are installed in the well, which store the data on an internal memory at selected time intervals and transmit the data to a server which is online accessible.