Lake Corpus Christi is not low. Yes it is not at full pool but 3.90 feet low is not that bad in my books. All in all the Frio just hasn't got the rain on it like the other rivers.
No, it's not dire by any means but it's a matter of perspective. It's at 73.8% full. The lake is only 60ft deep. Every foot is significant. At full pool the lake is about 18,000 surface acres. Right now its about 16,000 surface acres. So every foot is about 16,000 to 18,000 acre/feet of water. From a fishing perspective 3-4 feet is not bad but from a conservation pool perspective it is more significant.
For comparison Medina is about 6,000 surface acres so every foot towards the rise to full pool is only about 6,000 acre/feet of water. Medina is also about 150ft deep. Both lakes hold about 250,000 acre/feet of water at full pool.
It takes a lot of water to keep Lake CC at a particular level due to its surface acreage. Choke only has about 13,000 surface acres now so a foot drop in CC cannot be made up for by releasing a foot from Choke.
Perhaps the only way to get Choke full is a tropical event to fill both of them up.