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The two questions most frequently addressed are:
The two questions most frequently addressed are:
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#How quickly is surface ponding being infiltrated beneath the surface?
#How quickly is surface ponding being infiltrated beneath the surface?
#How quickly is the facility draining through exfiltration to native soils and/or through an [[underdrain]]?
#How quickly is the facility draining through exfiltration to native soils and/or through an [[underdrain]]?
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*Where possible, wells for measuring water levels within [[permeable pavement]] systems should be outside of trafficked areas.
==Shallow wells==
To measure the depth of ponding and the rate at which the ponding water infiltrates, install a shallow well with a water level logger:
* Use a perforated pipe (a piezometer) that will allow surface water to enter the well but will help prevent sediment from accumulating within it.
* Locate the well where ponding occurs first - near the inlet or the lowest point in the feature.
* Measure where the ground surface is relative to where you will be taking your water level measurements.
* Ensure there is a small reservoir in the well to keep your level probe submerged in dry conditions. This practice will also help with calibration.
==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:
* 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.
* Install the well so that surface water will not impact the water level within the well. A standard monitoring well casing over the well pipe should be sufficient.
* If possible, measure the depth of the underdrain. Having this measurement helps determine when water is percolating into the underdrain.
* Ensure there is a small reservoir in the well to keep your level probe submerged in dry conditions.
* Where possible, wells for measuring water levels within permeable pavement systems should be outside of trafficked areas.