Changes

*Thank you, we provided acknowledgement of ownership now - much appreciated!

*Thank you, we provided acknowledgement of ownership now - much appreciated!

 

'''10 June 2019'''

'''28 May 2019'''

''Often asked to provide a specification for deeper monitoring wells. This is a good start. More specifications please. Minimum diameter 100 mm, as smaller pipes tend to bend when soil is backfilled into the trench. Rigid material such as PVC preferred. Perforations only along the bottom where it intersects with the stone drainage layer. Lockable cap preferred. Top elevation above surface overflow elevation (you have that one, but hoping they don't forget about the overflow pipe at surface if there is one). Sock to keep sediment out of the well. Perforation spacing similar to typical perforated drainage pipe. Bottom should penetrate below the drainage pipe and into the native soil by at least 150 mm as the sensor is not at the very bottom of the instrument. This allows calculation of drain down time of water between the invert of the drainage pipe and the native soil. If the drainage pipe is installed in a small v-notch trench, the well should extend min 150 mm below the invert of this pipe. Deeper wells may also be installed to monitor groundwater table fluctuations below the facility, in which case the well must extend below the lowest annual elevation of the groundwater table. Simple schematic would be helpful. See Lakeshore pilot drawings as example. Normally we are using the monitoring well to measure water level fluctuations in response to rain events - you mention that it is used to measure water retention in the well, which may be confusing.''

''Often asked to provide a specification for deeper monitoring wells. This is a good start. More specifications please. Minimum diameter 100 mm, as smaller pipes tend to bend when soil is backfilled into the trench. Rigid material such as PVC preferred. Perforations only along the bottom where it intersects with the stone drainage layer. Lockable cap preferred. Top elevation above surface overflow elevation (you have that one, but hoping they don't forget about the overflow pipe at surface if there is one). Sock to keep sediment out of the well. Perforation spacing similar to typical perforated drainage pipe. Bottom should penetrate below the drainage pipe and into the native soil by at least 150 mm as the sensor is not at the very bottom of the instrument. This allows calculation of drain down time of water between the invert of the drainage pipe and the native soil. If the drainage pipe is installed in a small v-notch trench, the well should extend min 150 mm below the invert of this pipe. Deeper wells may also be installed to monitor groundwater table fluctuations below the facility, in which case the well must extend below the lowest annual elevation of the groundwater table. Simple schematic would be helpful. See Lakeshore pilot drawings as example. Normally we are using the monitoring well to measure water level fluctuations in response to rain events - you mention that it is used to measure water retention in the well, which may be confusing.''