help with drainage issue

I want to do some landscaping around my mailbox. However, the yard drains where I want to put my bed. The picture shows it. The lawn slopes down to a rock and cement drain that goes under the driveway (which you can't see in this picture) Can I just put a drain underneath the mulch that will be there for the short distance between the edge of the bed and the cement? My husband thinks it will be a disaster and the mulch will just run into the drain and clog it up (the drain is about 2 feet in diameter. Its big).

Here is how I would do this:
Add more of the retaining wall product to make the planter area (the dug up lawn, I presume) closer to level. About equal to the mailbox side of the drain. Add some filter fabric on the inside (the planter side) of the new retaining wall.
Those blocks do not seal off the water, but they will act as a filter so the coarser material (like mulch) will not go down the drain. The filter fabric will stop enough of the fines so the last bit of whatever gets through will not be a problem.

Use boulders to divide the lawn and planter area where the swale is. (a few feet from the driveway) and hide a drain pipe in there so water from the swaled lawn will still enter the drain. A catch basin with some filter fabric will keep the drain clean, as long as you clean it a couple of times per year.

Alternate idea:
Re-sculpt the area to make a 'dry' creek bed with rounded river rocks. Allow for collecting the water from the lawn, and discharging it to the drain.
Cobbles from 4-10" diameter will make up most of this, then scatter some smaller rock on top of the cobbles.
Then plant (and mulch) around the 'dry' creek. When it rains, the creek will really flow, and will still act as a filter to keep the fines out of the drain.

Catch basin:
A void, a space, a volume with a pipe for outflow.
The pipe is set up either from the bottom or the side such that there is some space on the floor of the catch basin to collect debris. The debris (gravel, sand, and even leaves) mostly stays below the pipe, and you clean it out occasionally, so the debris does not enter the main drain.
The lid of the catch basin is usually a grid, and you can have a coarse grid that allows more water flow, but may admit more debris, or a finer grid that keeps the debris out, but cannot handle as much water.
If you set this under the cobbles in option 2 then the cobbles will act as a filter to keep the leaves out, but you have to move the cobbles to clean the drain.
If you put this in a planter area with mulch the grid will keep out the coarse mulch, but it could plug up, since mulch decomposes over time and becomes a mix of coarse and fine materials. You would have to keep it clean.

Here is the basic idea.
http://www.ndspro.com/drainage-systems/catch-basins-and-grates/square-catch-basins

Wow, thank you so much for all the time and effort you put into your answer. I think the alternate suggestion seems doable for me. I never thought of a dry creek bed type of drainage system. It will take some doing but I'm determined to make it work! I'll take pictures along the way and keep you posted. Thanks again. Robin

I have done dry creek beds that double as real drainage systems when there is water that needs to drain.
Part of making it work is that the dry creek bottom needs to be exactly where you want the water to go, and the sides need to be deep enough to keep it there.
Obviously this idea will not work if Noah starts building his ark again, but for average garden drainage problems this can be a good, workable and nice looking solution.

One of these was really complex. Long stream, dry 'waterfall' at one end, and the stream looked like it ran under the walkway. In reality the water was picked up by a catch basin under the cobbles on each side. But the dry creek effect was continued on the both sides of the walkway.

My husband and I are working on this. What do you think of this idea? The pictures show it best. We dug a ditch and laid pipe in it so that the top of the pipe is level with soil line. We drilled holes in the pipe. We will lay the river rock over that and hopefully the water will drain just fine.

My take on it is that the two foot drain is there for a purpose. Your pipes are WAY too small. That drain under the road doesn't drain just your lawn but has to handle all the water that falls on your side of the road and on all the grass to where ever the next drain or the top of the hill is.

If your landscape project creates flooding in the road I'd expect the government body that owns the road to remove it as I can almost guarantee that it's located on their right of way.

Have you considered moving your mail box up the road a little.

No.
Perforated drain pipe is not the answer to a surface drainage problem. Even if it was, the holes are on the wrong side of the pipe (they should be on the bottom).

The pipes are too shallow. To act to carry away the water they need more slope. I would make the outlet almost at the bottom of the drain culvert.

You should have a large catch basin to take in the largest % of the surface water.

Set up the catch basin just low enough that the water will enter it easily. This may be just below the surface of the original soil level. Then solid (not perforated) pipe will drain it to the culvert. Given the large size of the culvert I would use nothing smaller than 6" pipe. You can cover this with cobbles as I suggested above, turning it into a dry creek effect when there is not any excess water, and making a very good drainage area when there is water.
An average flow of surface water will enter the catch basin, and excess can flow along the cobbled area to enter the culvert. A catch basin is designed for easy clean out, and in case of more flow, the cobbles will filter the water somewhat, so there will be less dirt entering the culvert.

The basics of this situation have been studied quite a bit, and here is more information.
http://en.wikipedia.org/wiki/Swale_%28landform%29
http://en.wikipedia.org/wiki/Surface_runoff
See the pictures at the top of each link? That is what I am seeing in your area. The grassy meadow type of grass or mowed turf holds the soil and slows the water run off, and filters out the debris. The large area (the swale is quite wide) contributes to the slower flow when there is not much water, and gives a larger volume a place to be until it can drain off when there is a lot of water. You can cover the catch basin with cobbles and enough of the surrounding area to make it look like a dry creek. (large rock, 3 or 4" min diameter). But everything you do needs to be done while thinking about the 'worst case' scenario: What happens when there is so much rain coming down the swale that it needs to enter the culvert fast, with the least obstruction?

Your wimpy pipes, shallow installation and wrong materials will not solve the problem.
When you have a drainage problem and it has been solved (looks like an engineered swale parallel to the road) you need to work with that solution, not set up barriers to it.
Create enough of a dry creek area (large square footage) to handle the maximum water flow.
Plant away from that, uphill and on the sloping sides. On the sides the plants should be soft, non-woody, so that if a flood happens they will bend with the water flow.

Alternate idea: Add to the lawn, low flowers that can be mowed. Do these grow in your area:
English Daisy
Clover (Dutch White)

Add some things right at the mailbox, and leave the culvert alone.

Another idea:
Find out who called for the swale, who designed it, and ask them what would be acceptable ways to make it more attractive, yet still function.