Grates, catch basins and drainage pipe selection
Drain grates for landscape use range in size from 3 to 12 inches across. Use common sense when determining the size of grate you install. The size you'll need depends on how much water will drain and how large your drainage area is. If an entire lawn is surface draining to one location, a 9-inch surface drain will obviously perform better than one that is 3 inches.
An atrium grate-shaped like a bell-sits partially above grade and is useful in places where mulch, leaves or debris might clog a flat grate. Golf courses typically use a 12-inch grate on top of a catch basin. Catch basins are subsurface collection structures with a grate on top and can also serve as a central junction box where drain lines from other basins are connected. You can build a catch drain yourself or buy them from any drainage-product manufacturer.
A faster, less-expensive installation technique is to put a grate right on top of a pipe riser. However, catch basins have an advantage over simple riser-grate installations because you can open and clean them if they become clogged. For this reason, a drainage system with catch basins is always easier to maintain than a system using only piperisers.
The most common types of drainage pipe are white, smooth-walled PVC or black corrugated plastic. Both types also are available as perforated pipe for seepage drainage. However, nearly any type of pipe (including PVC irrigation pipe) 3 inches or larger will work as drainage pipe as long as the fittings that you use will fit the outside pipe diameter properly. Drainage fittings are similar to irrigation fittings in that they come in a variety of shapes and sizes to fit various piping systems.
You will rarely need anything more than 4- or 6-inch pipe for a commercial or residential project. On golf courses and other large properties, you should call a qualified landscape architect or engineer if you have doubts about sizing the drainage lines. If the lines are too small, the area will still drain, but it will take longer.