Changes

[[File:trimble unit.JPG|400px|thumb|right|Always confirm elevations throughout construction. (Photo source: CVC)]]

[[File:trimble unit.JPG|400px|thumb|right|Always confirm elevations throughout construction. (Photo source: CVC)]]

Excavation to the sub-grade will differ depending on whether the design is for a full infiltration, partial infiltration, or no infiltration LID system. If it’s a full infiltration or partial infiltration practice, the sub-grade should be as level as possible to promote even infiltration across the facility’s footprint.  For no infiltration designs,  excavate sub-grade slopes to the design grade in the direction of the underdrain, typically 1 to 5%.  

<u>Excavation to the sub-grade</u> will differ depending on whether the design is for a [[Bioretention: Variations|full infiltration, partial infiltration, or no infiltration LID system]]. If it’s a full infiltration or partial infiltration practice, the sub-grade should be as level as possible to promote even infiltration across the facility’s footprint.  For no infiltration designs,  excavate sub-grade slopes to the design grade in the direction of the underdrain, typically 1 to 2%.  

As with all infiltrating LID practices, avoid compaction of sub-grade soils whenever possible. However, depending on the design and the local municipality, compaction of the sub-grade may be required for permeable pavement LIDs.

As with all infiltrating LID practices, avoid compaction of sub-grade soils whenever possible. However, depending on the design and the local municipality, compaction of the sub-grade may be required for permeable pavement LIDs.

*Confirm final excavated depths and slopes.

*Confirm final excavated depths and slopes.

'''Mistakes to avoid'''

'''Mistakes to avoid'''

*“Eye-balling” depths and slopes

*“eye-balling” depths and slopes