Has anyone had any luck damming a seasonal / dry creek bed and creating a pond?

Done a lot in many areas to collect the most water, but the material in the drainage is the key to it holding water. Also need to look at how many acres drain into it. NRCS can help you with that and sometimes have funds to cost share when built to their specs.

Definitely run the ropes prior to doing so. There are a ton of regulations and restrictions when it comes to that.

And, more regs coming every day from the EPA.

I have a seasonal creek. I tried damming it twice but floods took it out. If you don't core it down to good clay on the bottom and sides, water will run under it and then it's just a matter of time. The second time, I covered it in concrete and rip rapped it. It still went.

Like already mentioned, if you are building a new dam, and the creek has a name, it might be a violation of law. Of course, if there was an existing dam and you where repairing it, then you are grandfathered in and nobody can say anything about that. I met a guy in CA that builds ponds and he said he never built a new one, he always fixed existing ones. That way when the power that be in CA came after him or the landowner, they had to prove that there had never been a dam or a pond there at any time in the past. This worked especially well against the environmentalist who wanted to take private land from the owners to create more parkland by claiming threatened species lived there. I have some first hand experience playing that game there!!!

As for the dam,the reason they fail is from water going over them. Usually it's from a really big storm, but sometimes from a lot of storms right after another and you get a lot of flow. Whatever you do, be sure to build for the most extreme conditions and not rely on a pipe for overflow. A ditch around the dam that is big enough to handle the water, or a massive concrete spillway.

I know 'navigable waters' come into play, and for some reason 200 acre-feet seems like an important number to stay under without getting on the TCEQ/NRCS radar.

I have had NRCS out to both my places IRT pond creation and upgrade. They have been very helpful and walked me through the requirements, none of which were particularly difficult to accommodate in my case.

OK, I just had to revisit this for work. Wanted to try to point the OP in the right direction as well. See TCEQ's document GI-228 (rev. 3/09), "Rights to Surface Water in Texas":

"Domestic and livestock use. Also called D&L use, this refers to
water used to water range livestock, meet household needs, or irrigate
a yard or home garden.2 If you live on a river or stream and
use the water in this way, then you do not need a permit. You may
also impound water in stock tanks on your property, provided that
the average volume of water stored in any 12 consecutive months is
200 acre-feet or less. D&L use is exclusive to the owner of property
adjoining a stream. You may not sell the water or the water right
separately from the land, and, if you sell the property, this exemption
stays with the property.
✦ Wildlife management. In 2001, the Legislature added wildlife
management as an exempt use. Under this use, you may build on
your own property a dam or reservoir that normally holds no more
than 200 acre-feet of water. This reservoir must also be on qualified
open-space land, as defined by Section 23.51 of the Texas Tax
Code. If you have questions about whether you qualify for this
exemption, call our Water Rights Permitting and Availability section
at 512-239-4691 or e-mail us at <wras@tceq.state.tx.us>."

Please excuse the formatting and improper citation - I just copied and pasted. Hopefully none of y'all are English teachers/profs. A grammar Nazi I can handle as I tend to be one, but this is for brevity.