{"id":6693,"date":"2018-01-29T02:33:14","date_gmt":"2018-01-28T18:33:14","guid":{"rendered":"https:\/\/www.envguide.com\/%e5%9c%b0%e4%b8%8b%e6%b0%b4%e7%9b%91%e6%b5%8b%e4%ba%95%e9%92%bb%e4%ba%95%e6%96%b9%e6%b3%95\/"},"modified":"2018-04-05T21:12:47","modified_gmt":"2018-04-05T13:12:47","slug":"environmental-drilling-method-for-groundwater-monitoring-well-2","status":"publish","type":"post","link":"https:\/\/us.envguide.com\/environmental-drilling-method-for-groundwater-monitoring-well-2\/","title":{"rendered":"Environmental drilling method for groundwater monitoring well"},"content":{"rendered":"
<\/p>\n
Before the construction of the groundwater monitoring wells, it is necessary to conduct a preliminary investigation of the site, to determine the subsurface site stratigraphy (e.g., soil type and bedrock determination, and to confirm the approximate distribution of the contaminants. This will aid in the selection of the appropriate monitoring well construction and the depth of the well that needs to be installed. To carry out this work, it is required to use drill rigs to collect soil samples in order to conduct the initial screening of the soil for contaminants. These data provide the basis for the development of long-term groundwater monitoring programs for the site including the depth and location of the monitoring wells.<\/p>\n
Environmental monitoring wells are used to obtain representative groundwater samples, so their construction cannot use materials and tools that alter the physical and chemical properties of groundwater.<\/p>\n
The types of drilling methods are mainly determined by the use or non-use of circulating drilling fluids. These fluid contains a complex polymer which may not be suitable for environmental drilling. Once into the groundwater, it may increase the difficulty and cost of purging the well. However, the use of these drilling methods maybe necessary depending on the depth of the monitoring well and the geologic formation. Some drilling methods use compressed air, which may also bring oil and contaminate the subsurface soil.<\/p>\n
The following are some common environmental drilling methods:<\/p>\n
1. Hollow Stem Auger<\/p>\n\t\t\t\t\t<\/div>\n
Hollow Stem Auger (HAS)<\/strong>is the most common drilling method. HAS can be used to obtain continuous soil core samples. The drilling method does not require use of any drilling slurry, suitable for semi-consolidated and non-consolidated soil to complete less than 30 meters deep of drilling work. HSA can also install pre-packed monitoring wells to expedite the process of well installation. But the HAS will produce drill cuttings wastes.<\/p>\n