A Guide to Drainage
FOLLOW US ONLINE TWITTER . COM / FOOTYFOCUSMAG
This is why a grid system is more common for sportsturf areas . The main drain can be positioned off the playing surface . For pitches this can be beyond the side-line , for golf courses this can be at the side of a fairway or off the green . Laterals then form a grid across the playing surface into the main .
One common misconception about drainage is that it is supposed that drains should run downhill ! Yes they should have a slight fall of something around 1in 100 and this is called the ‘ grade ’ of the drain . But on sloping ground they should not run downhill to follow the lie of the land . Instead laterals should run across the slope following the contours of the land . Effectively each lateral then becomes an interceptor drain reducing the amount of water moving down the slope . This is why you can have the strange phenomenon of a main drain appearing to be on the high ground . On the high side of a fairway for example where even the main drain can also be an interceptor .
Interceptor , or cut off drains such as ditches , swales , and french drains , can have an important role as part of a drainage scheme . Most soils become waterlogged due to groundwater , but there are many cases where land is wet due to surface run off from land at a higher level . The installation of an interceptor drain to catch the water before it runs downhill may in some cases alleviate the problem to the extent that no drainage , or much less drainage is necessary at the lower level .
FINALLY
There are two things to establish before starting to drain - where is the water coming from , i . e . the cause of the problem , and where is it going to go to – the outfall ?
QUALITY STANDARDS
The LDCA publishes industry standards for agriculture and sportsturf that all LDCA Contractor members undertake to work to . They cover quality of materials and workmanship . These are downloadable from the LDCA website together with a list of contractors . www . ldca . org and click on ‘ Members Directory ’.
Suite 217 , 29-30 Horse Fair , Banbury , Oxfordshire OX16 0BW Tel : 0845 5191 243 email : secretary @ ldca . org www . ldca . org
12 Issue 67