Groundwater

Groundwater well with sand separator Photo: L. Schwankl

Groundwater sources present possible clogging hazards for microirrigation systems. Some of these are also common to surface water sources (particulate matter and biological contaminants), but in addition to these groundwater may present chemical precipitate hazards that are seldom encountered with water from surface water sources.

Particulate matter such as sand, silt, and clay particles are frequently present in groundwater. Many agricultural wells are prone to pumping sand, especially at start-up when the flow rate is particularly high during the initial filling of the irrigation system.

Biological clogging problems are much less common when you use groundwater than when you use surface water sources. It can occur, though, especially where dissolved iron or manganese is present in the water. In that case, iron or manganese bacteria can be present in the well and in the irrigation system. Other biological contaminants that can cause clogging can also grow inside the microirrigation system.

Chemical precipitates that can result in the clogging of emitters can pose a much greater potential hazard when you use groundwater as compared to using surface water sources. Water constituents such as calcium, magnesium and iron are in solution in the groundwater but can precipitate, becoming potentially clogging particles, when pumped from the ground and exposed to air.

For more information on Assessing Water Quality and Taking a Water Sample, click here.