Explore the essential components of water level monitoring programs.
Before discussing the uses and importance of long-term water level data, it is useful to review essential components of a water level monitoring program. These include: selection of observation wells, determination of the frequency of water level measurements, implementation of quality assurance and establishment of effective practices for data reporting.
Commonly overlooked is the need to collect other types of hydrologic information as part of a water level monitoring program. Meteorological data -- such as precipitation data -- aid in the interpretation of water level changes in observation wells. Where observation wells are located in alluvial aquifers or other aquifers that have a strong hydraulic connection to a stream or lake, hydrologic data -- such as stream discharge or stage -- are useful in examining the interaction between ground water and surface water. Meteorological and streamflow data commonly are available from other sources; but if not, some monitoring of variables such as streamflow and precipitation may be needed to supplement the water level data, particularly in remote areas or in small watersheds. In addition, water-use data, such as pumping rates and volumes of pumped water, can greatly enhance the interpretation of trends observed in water levels and explain changes in the storage and availability of ground water that result from water withdrawals over time.