The Basics of Drainage on a Golf Course
For some drainage might not be the most exciting subject, but when it comes to golf course design it really is crucial. Not only is drainage important during design and construction but also after the course is open. Surface and sub-surface drainage is an ongoing part of a good overall maintenance plan.
On a golf course drainage is needed to remove water away from the playing surfaces allowing it to remain playable following and even during heavy downpours. Good drainage will also help prevent damage to the turf which can occur when water accumulates into puddles and is left standing for too long.
From the outset establishing how and where surface water will be directed has to be defined. If water is going to enter existing drains or waterways permisions will have to be obtained. Depending on climate conditions surface drainage can run into millions of gallons per month/year. If the golf course is part of an overall development this can have major implications on cost and design. Climate change concerns that water resources will be limited in coming years is now also influencing design. Ideally water will be collected in lakes and then re-used as part of the irrigation system.
The design process will begin with a site visit, following which a Site Analyis Plan is drawn up to establish low points, valleys, slopes, watercourses, wetland areas and existing services. Existing geology and soil types also need to be identified as they can affect how water will drain, flow and collect.
The designer will always be thinking about drainage during the grading of the course. Indicated by contour lines on a plan the design will allow for surface drainage while retaining the flowing lines that make a golf course visually pleasing. Drains will collect surface water and divert it to low spots, the drainage system, streams and irrigation lakes.
Water can be directed away from the line of play using swales which then run into depressions. Catch basins in the depressions are then used to collect the water and filter any debris before it enters into the drainage system. Another option is to use trenches and french drains to gather water along the fairway. An extreme option is pumping which can be used to lift water out of an area of low-lying land.
Most golfers will have experienced problems with waterlogged areas on the fairway. These areas not only make playing golf less enjoyable but also damages and scars the fairway turf. To reduce this problem slit drainage can be used to drain fairways. This consists of parallel sand slit trenches that run along the fairway perpendicular to the water flow direction to remove excess water before it has chance to pond. The slit drains connect to collector pipes laid in a lattice of lateral drains which then link to main drains that tend to run parallel to the fairway(except where slopes do not permit). The lateral drains consist of a trench with a perforated pipe at the bottom and backfilled with gravel. Turf is placed over a permable membrane which makes them almost invisible to the eye.
Gravel Sumps are another means by which to collect water in low areas. Gravel sumps are commonly used in out of play areas where the topography does not permit the use of a piped drainage system. A Gravel Sump is basically a pit filled with drainage stone material and often lined with a textile fabric to prevent the surrounding earth contaminating the stone.
Sand Bunkers can be difficult areas of the course to drain as they are normally set lower than any other part of the surrounding course. Bunker drainage is notorious for becoming blocked and ideally surface water should be directed away from the bunkers. This can be done by shaping surrounding ground to divert water away. Typically the drainage pipes in bunkers are designed in a herringbone pattern.
Green drainage is especially important to avoid puddles and general wet areas which will impact on play. Green drainage consists of perforated pipes or drainage tiles laid out in a herringbone pattern. To make the green drain efficiently it’s important to lay out drainage pattern perpendicular to the flow of water across the slope.
Drainage maintenance is an ongoing process. Regular drainage maintenance may involve sand slitting, aerating, top dressing and clearing debris from ditches and the like. Catch Basins have to be regularly maintained to clear debris from the grate on the surface so that the drainage is not inhibited, and periodically the trap at the bottom of the catch basins have to be cleaned. It is proper maintenance practise to keep an up to date drainage works plan to record all repairs and maintenance to the drainage system.
The theory of Drainage is simple, it works on gravity…water always runs downhill!