Hopefully someone here can help in regards to the drain we have in front of our garage on our driveway. I have added a couple of images that should help make sense of my explanation! The drain is at the foot of our driveway which is sloped and over the years it seems to have filled up with soil, dirt, leaves etc. So much so that whenever it rains the drain overflows and we have a large puddle over the whole area. This eventually drains away but is getting worse over time. The problem is I cannot see any way of getting access to the drain to clean it out because it's solid concrete.
You could try a pressure washer see if that will dislodge all the muck, or take the top off where the downspout joins into the drain and see if you can get some drain rods/jet down there?
Alternitvely is there not an inspection chamber nearby that leads back to the slit drain, you might be able to rod back from this?
As DNG says there is probably a connection from the channel into the line downstream of the downspout, it looks as though someone has had a go in the past looking at the hole in the end channel.
The easiest way to clean these out is to cover the slots with a roll of visqueen or dpc and weigh down with planks, you then high pressure water jet from one end or the other.
In this case you have limited access and no way of getting the silt out so you will just wash the silt down the line which may cause future blockages.
Contact a decent drainage contractor and tell them they need a thin leader hose for their jetting unit, with a bit of luck they may get it going if not there may be some digging required to get better access.
Another alternative is to carefully cut open the end of the channel and fit a small access plate afterwards, not easily done and i wouldnt do it if it is under the wheel line
