Ground Water

The main purpose of establishing a groundwater monitoring network is to obtain representative samples of water levels throughout an aquifer of interest. Site selection for monitoring stations is critical for adequate representation of the hydrologic conditions in the aquifer. Monitoring stations spaced too far apart result in an inaccurate understanding of the physical hydrology of the aquifer whereas monitoring stations placed too close together can generate redundant data and unnecessarily increase the costs of the network. The selection of sites for groundwater level monitoring depends largely upon the objectives of the data collection effort however the following general considerations should be made when selecting individual monitoring sites:

Site Selection

• The site is accessible during all weather conditions.
• If telemetry is required for real-time access to data from the station, there is a good GSM signal or a clear line-of-site to the INSAT or VSAT satellite is possible.
• Either AC power or adequate sunlight for charging batteries using solar panels is available.
• Operational wells with pumps have access ports for deploying instruments and ideally have a separate conduit to keep the AWLS communication or support cables from interfering with the pump or electrical cables.
• The site is secure to avoid vandalism or theft of instruments and civil structures.
• The property owners are notified and have approved of the installation of the monitoring station.

Installation

• It’s important to establish datum at each observation well. This can be done by conducting a level survey from a nearby benchmark or other reference mark having a known elevation or by using a GPS system with 2 cm accuracy.
• The measuring point and associated elevation is clearly marked on the wellhead or the top of the well casing.
• Datalogger and transmitter, if so equipped, are secured in a NEMA type 4 enclosures or equivalent to prevent access by water, dust, or insects.

Operation

• Data should be downloaded from the data logger during each visit unless the data have been previously received by means of telemetry device.
• Power supplies, including solar panels and batteries, should be checked during each visit to ensure they are adequately powering the system.
• Replacement equipment should be brought along on the site visits to avoid extra trips in the event that equipment is malfunctioning and needs replacing.

Questionnaire

• Will the data generated from this site add to the overall understanding of the physical hydrologic properties of the aquifer? If no, consider an alternate site.
• Is the information generated by this monitoring station regarding the aquifer’s hydrologic properties redundant? In other words, do existing monitoring stations already provide this information? If yes, consider eliminating this station from the network.
• Do operational wells with pumps being proposed for monitoring have access ports for deploying instruments and ideally have a separate conduit to keep the AWLS communication or support cables from interfering with the pump or electrical cables? If no, consider another well with access ports or include plans to install a port through which water-level sensors and cabling can be installed.
• Is power available at the site and if not, would it be feasible to power the monitoring instruments and telemetry equipment with a solar panel and battery system? If no, consider an alternate site.
• Is the site easily accessible by road to facilitate the operation and maintenance of the instruments and housing structure during all flow and weather conditions? If no, consider an alternate site.
• Is the site being secure to avoid vandalism or theft of instruments and civil structures? If No, consider an alternate site.