Golf courses with heavy soil greens are installing slit drains to reduce water retainage. The results are good but sod striping may occur.
Golf drainage contractors have sold many golf courses on green slit drainage. After a site survey identifies a sensible drainage discharge point, the contractor or architect develops a piping plan with lateral lines spaced 6 feet wide fed into a collector pipe that discharges into a low area. Most contractors cut the green sod and number it with chalk so that it is replaced in the same location.
Next, a small trencher cuts a 12″ trench and the spoils are removed and disposed. The contractor next installs 1.5″ slit pipe (a single wall perforated pipe with or without geofabric envelope). Now the problems start.
One cannot backfill the trench with the removed green mix; it won’t percolate and this defeats the purpose of the drainage pipe. To percolate water, contractors backfill the trench with a 70/30 sand/soil mixture that efficiently drains water. They cannot use 100% perc. sand recommended by engineers because of obvious agronomic issues.
After project completion the golf superintendent is faced with a green or collection of greens with differing subsoil strata every 6 feet. Hand watering is strongly recommended but even the best supers end up with uniform stripes across their greens. Those that don’t hand water have more serious problems.