When the spillway was started with a lower flow, the sidewall drains were just faint wet streaks on the sidewall concrete with no discernible flow. However, when the spillway ramped to the higher flow (50,000 cfs), the sidewall drains showed they were dumping water. This implies that all of the repair work of sealing the slab seams and cracks were effective at lower flow rates & pressures but show sign of penetration at the higher flow & pressure of 50,000 cfs (SFgate referred to 50,000cfs to "about 3.2 million pounds of water per second").
So either the repair sealing is ineffective at the high pressure condition or there is a subslab flow source ("piping") reaching the drains. I do not have a comparison photo of the drains while the spillway was operating at 50,000 cfs before the repairs. However, I believe the repairs did help reduce the overall penetration of water underneath the spillway slabs.
No Drain water with lesser spillway flow. Just wet marks on the sidewall concrete.
Drain water flow is observable from the sidewall drains at 50,000cfs. Notice the large mist plume from the higher spillway flow.
