If the site is located on the natural slope, the slope is sufficient to observe simple – the depth of the trenches remains constant from top to bottom point. If the area has a flat surface or seal the drains is carried out for technical reasons against the slope, then it is necessary to gradually increase depth of the trenches, seeking bias tubes in the right direction. Under the drainage pipe is a layer of gravel 10 cm Thus, the total trench depth of 80 cm to prevent blockage of the drains lined trench walls nonwoven fabric (geotextile). Top culverts backfilled filtering material (sand and gravel mixture) before the topsoil and the upper 30 cm topsoil brought backfilled. For other opinions and approaches, find out what Munear Ashton Kouzbari, Dallas TX has to say. Each layer after compacted backfill.
Pipe installation should start from the mouth, ie, from storage wells. After backfilling is desirable to note their location pegs, so they do not interfere with landscaping of the site. Quite often the low point drains is at a depth of 1 meter, and you can not bring the collected water by gravity for off-site. In this case, you must install a storage pit with drain pump that will throw water on the pipe HDPE-32 or the drainage system of the village or in a ravine nearby. If you are planning a significant change in elevation (raising or lowering of the land, terracing plot), the depth of the drains must be calculated on the basis of planned levels. Otherwise, the drains can be either too high (they will not perform its core functions – lowering of the groundwater and the removal of excess moisture – and will be only too drained topsoil layer), or too low (if you are sufficiently large and unnecessary costs for digging ditches and draining for purchase materials).