I did a soil percolation/infiltration test to determine how quickly water drains through the soil:
- Dug a hole approximately 12" in diameter to the planned depth of the dry well.
- Filled with about 2 feet of water
- Let it drain completely to saturate the soil
- Filled it again with another 2 feet of water
- Measured total drainage after 1 hour
- Result was 6.5" of drainage after 1 hour, or a little more than 1" per 10 minutes
Assuming I've calculated the right number of dry wells and permeable gravel backfill to surround the wells (that is total storage volume is appropriate for rainfall rates and roof area), is that soil drainage rate adequate for this application?