Changes

==Deeper wells==

==Deeper wells==

Some LID features which are designed to retain water during precipitation events store stored within the media that makes up the LID feature (e.g. [[permeable pavement]] will be on top of a gravel bed where water can be stored). To measure the amount of water retention in a monitoring well, install a water level logger:

Some LID features are designed to retain water within the media that makes up the LID feature (e.g. [[permeable pavement]] will be on top of a gravel bed where water can be stored). To measure the amount of water retention in a monitoring well, install a water level logger:

* Install the well while the feature is being constructed or undergoing major maintenance.

* Install the well while the feature is being constructed or undergoing major maintenance.

* If there is an underdrain in the feature, make sure the bottom of the well reaches below it.

* If there is an underdrain in the feature, make sure the bottom of the well reaches below it.

===Monitoring Well Specification===

===Monitoring Well Specification===

The monitoring well should be installed during construction in a pervious area within the trench between tree planting areas.  The well should be vertical from top to bottom.   

The monitoring well should be installed during construction in a pervious area within the trench between tree planting areas.  The well should be vertical from top to bottom.   

'''Material''' The pipe should be rigid to prevent bending (e.g. PVC).

'''Diameter''' minimum 100 mm

'''Perforations'''  The perforations may be similar spacing similar to [[underdrain]] pipes. Perforations are only required on the bottom third of the pipe. The well should be sealed at the surface to prevent short circuiting of surface water flow along the sides of the well.  Bentonite clay is often used for this purpose.

'''Sock''' The perforated portion of the pipe should be wrapped with a geotextile sock. Standard geotextile provided with perforated pipe may be used.

'''Bottom''' The bottom 100 mm of the well should be capped and free of perforations to provide a small reservoir of water to keep the sensor wet during dry weather.   

'''Length''' The well should extend into the native soil below the facility by a minimum 150 mm.  Top should be above the surface overflow elevation or above the maximum ponding depth to prevent surface water from entering the well.  If the perforated drainage pipe is installed in a v-notch below the bottom of the facility, the well should extend 150 mm below the invert of this drainage pipe.

|Material||The pipe should be rigid to prevent bending (e.g. PVC).

'''Cap''' The well should be finished with a lockable cap to prevent vandalism.

|Diameter||minimum 100 mm

|Perforations||The perforations may be similar spacing similar to [[underdrain]] pipes. Perforations are only required on the bottom third of the pipe. The well should be sealed at the surface to prevent short circuiting of surface water flow along the sides of the well.  Bentonite clay is often used for this purpose.

|Sock||The perforated portion of the pipe should be wrapped with a geotextile sock. Standard geotextile provided with perforated pipe may be used.

|Bottom/sump||The bottom 100 mm of the well should be capped and free of perforations to provide a small reservoir of water to keep the sensor wet during dry weather.   

|Length||The well should extend into the native soil below the facility by a minimum 150 mm.  Top should be above the surface overflow elevation or above the maximum ponding depth to prevent surface water from entering the well.  If the perforated drainage pipe is installed in a v-notch below the bottom of the facility, the well should extend 150 mm below the invert of this drainage pipe.

|Cap||The well should be finished with a lockable cap to prevent vandalism.