The code of Virginia Section 62.1-44.15:34.E.2.a, indicates  "Soil erosion control requirements and water quantity technical criteria adopted pursuant to this article shall apply to any activity that disturbs 10,000 square feet or more, although the locality may reduce this regulatory threshold to a smaller area of disturbed land. A plan addressing these requirements shall be submitted to the VESMP authority in accordance with subsection A. This subdivision shall also apply to additions or modifications to existing single-family detached residential structures."

If we are interpreting this section correctly, any land disturbance activity greater than 10,000 square feet would require compliance with water quantity criteria (channel and flood protection). 

The current draft of the regulation "Part V. Criteria and requirements for Regulated Land- Disturbing Activities" line 2464 in particular does not refer to 9VAC25-875-600 but only to 9VAC25-875-560 which might create confusion when interpreting the land disturbance area threshold for water quantity requirements