So, Record storms in Texas and Oklahoma is a thing. Hays County is adjacent to Travis to the southwest; most if not all the bad weather is coming from the west-southwest, so they're getting hit even harder than Travis county is, where I live.
For those playing the home game, Texas, like California, has been a drought state for several years; that was a key reason for the massive Bastrop fires a few years ago that could literally be seen from space.
As most of you can guess, getting rain is awesome; we need it. Getting it at this intensity and this fast isn't. On one hand, it's raising our lake water levels, which is super important; on the other....I'm going to give a very mild, non-drama example of the problem that places that are in danger are having.
I live on what's called a hundred year flood plane (this includes about a full third of Austin, btw). We have to get flood insurance, but actual flooding simply doesn't happen unless a lot of very specific conditions are met (I mean, usually its has to be the perfect storm of shitty luck). A few years after we moved to Austin, they remodeled the gully out back (Austin is filled with these) from a muddy dry creek run-off to a limestone-and-rock quarry that would be fucking awesome to intertube and it goes for miles in our neighborhood (and the equivalent exists in many others). So when rain hits, it looks cool--seriously, I'll put up video if needed, its awesome--and we can enjoy it because the highest it gets is stil about ten to fifteen feet below our backyard.
However, we've reached saturation of the ground at this point; it's not just not dry, it's wet as in squelch even after twenty-four hours of no rain (which has happened like, once in the past couple of weeks, maybe twice).
Patio: 12 feet from door to edge by about 18-22 ft; it's wet I'm not measuring now.
Yard: 20-26 feet from patio edge to the back fence.
Back fence: one foot before drop off to watershed.
So when it rains now--and it comes down hard and fast then slow and eh then hard and fast, break, repeat--the water is immediately in puddle form and from my understanding of physics and engineering, it's still running off to the back but not fast enough. Most recently, I watched in fascination as standing water crawled about four and a half inches up the patio to quiver there before the rain let off and it slowly withdrew back to the (already soaked) ground. Right now, it's standing just short of the patio, which is about three inches above dirt level at that point and one half inch from the top of the water standing there.
Here's what I didn't even know about flooding because where I grew up--rural--we were on top of hill and everything rolled down fast: your entire backyard does not have to be flooded and your watershed does not have to be overflowing and gravity and elevation sometimes work against you when speed is involved. My backyard right now has several high spots which are just mud that are higher than my patio, but right now--the rain just started again--the water just went over the lip of my patio again at the four inch mark and is crawling toward me.
However, math! The patio--due to age and dirt and maybe God--has a slight downward inclination due to settling over the years, so the water does have to work to get to me. And it's only like, maybe a quarter inch of water right now edging toward me like very shallow doom. So most of it's running back to the yard to supersaturated dirt and I need more geometry to work out how long it might take with x hours of rain and y amount of rain per x to get to my back door (which is about three inches above the patio) or possibly wonder why I'm trying to do the math of flooding right now.
Also, I'm resenting that little island of perfectly unflooded dirt (wet, granted) a few feet from the patio right now. Seriously, what's up with that?
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