5.4.12
Minimal Excavation Foundations
5.4.12.1 BMP Description
Minimal excavation foundations (BMP T5.19 in Volume V, Chapter 11 of the Ecology Manual) are defined as those techniques that do not disturb, or minimally disturb the native soil profile within the footprint of the structure. Pin foundations are an example of minimal excavation foundations.
5.4.12.2 Performance Mechanisms
By minimizing the disturbance and compaction of the soil, the hydrologic properties of the native soil are preserved.
5.4.12.3 Applications and Limitations
Minimal excavation foundations can be used to partially or completely achieve the LID Performance Standard associated with MR #5: On-site Stormwater Management, and the flow control standard associated with MR #7: Flow Control (Table II-5.16).
BMP | MR #7: Flow Control | ||||||
---|---|---|---|---|---|---|---|
List |
LID Performance Standard |
Basic |
Enhanced |
Oil Control |
Phosphorus |
||
Minimal Excavation Foundation |
X |
|
X |
5.4.12.4 Minimal Excavation Site Considerations
Foundations can be used in conjunction with downspout dispersion (Vol II–5.4.4 Dispersion BMPs) to receive further modeling credit.
5.4.12.5 Design Information
See the Runoff Model Representation modeling requirements in BMP T5.19 in Volume V, Chapter 11 of the Ecology Manual.
5.4.12.6 Minimum Construction Requirements
To minimize soil compaction, heavy equipment, including pile driving equipment that would degrade the natural soil profile’s ability to retain, drain and/or filter stormwater, cannot be used within or immediately surrounding the building. Tracked equipment weighing 650 pounds per square foot or less is acceptable.
5.4.12.7 Operations and Maintenance Requirements
There are no operations and maintenance activities specific to minimal excavation foundations. If used in conjunction with other BMPs, like downspout dispersion or post-construction amended soils, see the maintenance requirements associated with those.