|Length||Shallow wells should extend into the filter media by a minimum of 150 mm. Deep wells should extend into the native soil below the facility by a minimum 150 mm. Tops should be above the surface overflow elevation or maximum ponding depth to prevent surface water from entering the well. If the underdrain perforated pipe is installed in a shallow trench below the bottom of the facility, the well should extend 150 mm below the invert of the perforated pipe. | |Length||Shallow wells should extend into the filter media by a minimum of 150 mm. Deep wells should extend into the native soil below the facility by a minimum 150 mm. Tops should be above the surface overflow elevation or maximum ponding depth to prevent surface water from entering the well. If the underdrain perforated pipe is installed in a shallow trench below the bottom of the facility, the well should extend 150 mm below the invert of the perforated pipe. |