{"id":1237,"date":"2015-10-07T02:00:29","date_gmt":"2015-10-07T06:00:29","guid":{"rendered":"http:\/\/www.solinst.com\/onthelevel-news\/?p=1237"},"modified":"2023-04-06T16:51:18","modified_gmt":"2023-04-06T20:51:18","slug":"deep-groundwater-sampling-with-dvp","status":"publish","type":"post","link":"https:\/\/www.solinst.com\/onthelevel-news\/groundwater-sampling\/low-flow-groundwater-sampling\/deep-groundwater-sampling-with-dvp\/","title":{"rendered":"Deep Groundwater & Dissolved Gas Sampling With Double Valve Pumps"},"content":{"rendered":"\n\n\n
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Sampling groundwater from deep wells is a challenge on its own, but add to that the need for accurate dissolved gas analysis, and the task gets that much harder.<\/p>\n

Low Flow, Deep Groundwater Sampling<\/h2>\n

HydroTerra<\/a>, a leading Australian company, and exclusive distributor of Solinst products, provides environmental monitoring solutions. They have developed a method of low flow sampling that uses the Solinst Model 408 1.66″ diameter Double Valve Pump, to depths of up to 1,200 meters (3,900 feet).<\/p>\n

In order for Double Valve Pumps<\/a> to reach these extreme depths, HydroTerra use specially designed weights that fit to the bottom of the standard pumps. These weights counteract the buoyancy caused by the very long drive and sample tubing lengths. In addition, HydroTerra have designed custom-built wellheads to ensure an organized and secure setup for various diameter wells.<\/p>\n

\"Double<\/a>

A Solinst Double Valve Pump with Custom Weight for Deep Groundwater Sampling<\/p><\/div>\n

\"Double<\/a>

A Custom Wellhead Designed for Dedicating Double Valve Pumps for Deep Groundwater Sampling<\/p><\/div>\n

How do Double Valve Pumps work? When the pump is lowered to depth in the well, water fills the pump and both sample and drive lines to static level. Gas is supplied from a pump controller, which pushes down on the water column and closes the valve at the base of the pump. This forces water to cycle through the pump and up the sample line.  When the pressure is released, the top valve closes preventing water from draining down the sample line. To see how the Model 408 Double Valve Pump works, Solinst has a document showing its operating principles<\/a>. <\/em><\/p>\n

As part of their methodology, HydroTerra recommends dedicating one Double Valve Pump to each well, especially when sampling to these depths. They suggest dedication for the following reasons:<\/p>\n