roof rainwater running into pond

[jonnyp1]

i currently have roof rainwater running down a 65mm square downpipe along the garden fence hidden by hedge and into a small feeder pond into main pond. I want to take out feeder and run the rainwater under ground to main pond. I take it i cant just extend and bury the square downpipe. If not how do i convert 65mm into underground pipe, i need it as small as possible so i can hide it going into pond. any suggestions??
cheers jon

 

[Ian H]

You could do but the joins don't seal so roots might get in.

There are rubber adaptors that will take your rainwater pipe into 110mm underground pipe.

 

[jonnyp1]

so you would go 65mm square to 110 and then use adaptor to take it down to 32mm mdpe?

 

[Mw Roofline]

You could just use downpipe but it would be best to use round downpipe as it’s sronger than square when compressed by the soil, earth etc. Even though rainwater pipe isn’t solvent, get yourself some solvent cement anyway and glue the joints then tape up with duct tape.

 

[Ian H]

so you would go 65mm square to 110 and then use adaptor to take it down to 32mm mdpe?

No, 68or65 into 110, into your pond.

There's an 83mm as well.