Need alternative for U channel for viewing glass

Need help with Pond build.
I'm planning to have a viewing glass panel in my Pond, problem is I'm unable to find a u channel for the glass that is deep.
I'm only able to get one that is 3/4 th

any alternative or DIY which can be done? anything else i can use to safely hold the glass in place?

i was able to get this one.but its not deep enough