The rains on Oct 26 produced a minor flow event within Onion Creek. About 2-3 inches of rain fell in the Onion Creek watershed (contributing zone) upstream of the Barton Springs segment of the Edwards Aquifer. Flow within the Onion Creek at Driftwood reached a peak discharge of about 514 cfs at 7:30 pm. Peak flow reached the Antioch Cave Recharge facility about 7 hours later (it is about 13 miles downstream).
Antioch Cave is the largest-capacity recharge feature in the District. The District has recently completed a renovation of the recharge facility. The vault that overlies the entrance to Antioch Cave has two valves that can open, allowing recharge to the aquifer. The idea is that the valves are closed during the first part of a flood event, and then will open automatically as the water becomes cleaner. Click here to see the TCEQ's data for the site.
Here's the vault and recharge facility at Antioch Cave on the afternoon of Oct 26.
Here's the same vault a day later! Note the whirlpool above the vault.