Need help/advice with channel drain routing against foundation.

[kb1794]

Hi everyone, new member here. I'm in Houston TX, currently in the middle of a pool build about to pour the slab. I'm having a bit of a disagreement with my builder in regards to the channel drain he's trying to use. In Houston, we get massive downpours several times per year. Channel drain is approx 1.75" wide and runs directly against the foundation of my house. There's also 1 gutter downspout that handles most of the water from the back of my roof. The contractor just butted all the joints together and cut in the 45* angles, which some have approx 1/4" gaps in them. When I fill the drain with water, it doesn't even make it end to end, it flows out of all the joints. When I brought this issue up to the builder, he said it would be fine once the concrete is poured because it will seal the joints up and what little water gets out won't matter and won't affect the foundation. HMMM. I've attached some pictures of the issues I'm talking about, the standing water is from running the hose down the end for 30 secs. I'd really appreciate input/advice if the builder is correct and this is pretty standard practice, but to me it seems very shoddy....
Google photos link...
https://photos.app.goo.gl/9NhA7HfnihktYbB1A

[Denniswiseman]

It looks pathetic to be able to drain sufficient water from around the house. I would want a larger channel or design the drainage to fall to the centre away from the house