Crushed rock, concrete that has evenly distributed sizes from ¾ of an inch to ¼ inch down to fines. This allows for very good compaction. Base for paving stone has the ability to hold loads as its principle function. Drainage of water is accomplished over the surface or through drains below the surface. The base is a very poor medium for drainage.
Soil and base are composed of varying sizes of particles. A good mixture of particles is important for good compaction. This good mixture, as in Class 2 base, is composed of 5 to 8 percent fines. Fines are those particles that can pass through a #200 sieve. A #200 sieve is a screen that has about 350 divisions in one square inch. If water is poured over a #200 sieve it will not pass. Consequently base or soil that has over 8% of fines will not allow water to pass readily. Or it is poor for drainage while it may be very good for holding loads.
Artificial turf usually does not have to hold heavy loads but it must drain well. Sandy soil is the best for drainage but since the turf is held in place by 5 inch spikes the spikes will not hold well in a sandy soil.
A base material or system of drainage must be employed that can hold the loads, drain well and hold the spikes. The surface can be designed or crowned so that the water flows to the outer edges and into perforated pipes.
EXAMPLE:
The base was crowned slightly on the ball field so the water would not collect in puddles.
