Depends on how far back in time you wanna go. I’m just playing the odds and assuming the person who posted that hasn’t lived here their whole lives…
I live on Barton Creek, albeit a bit upstream. It got a pretty decent amount of water, and it’s still flowing nicely, but it didn’t really get THAT much water. We’ve had several storms over the last few years that contributed far more to it. The water is staying in the creek longer than it has in 4-5 years simply because the rain has come in several spurts, but we never got a sustained influx of a lot of water. Now, one more good deluge would probably do it, at least where I am, but that doesn’t seem to be in the cards.
20-30 years ago though? Yeah, I don’t know the answer. Growing up, there was water down there most years, even fairly late into the summer. Of course, there were bad years when it mostly dried up before school even let out, but those were the exceptions. They now seem closer to the rule. Purely from my own observations, it just seems like there’s far less residual, ground water. Back in the day, after heavy rains, it seemed like water was coming out of the ground (near the creeks) for weeks. Now, it’s a couple days at best. I’d assume that has a lot to do with construction and impervious cover doing a number of things (destroying a lot of those natural underground waterways, diverting water elsewhere, collecting water in retention ponds, etc). Just think about every culvert and storm drain. So much water is collected far from the creek and then dumped almost straight into it. All that water used to take days/weeks to work its way down to the creek. It now happens in minutes. That leaves the creeks to receive the initial runoff, but provides far less residual groundwater inflow. That leads to empty creek beds within days, even after torrential downpours.
There’s surely other reasons, but I’d be shocked if my theory isn’t a huge contributing factor.