This project required drainage due to not only the home adjacent being situated at a higher level but also, the homes behind the property having a two foot grade difference. The area to be trenched will be 150 feet which is up to the point where the yard starts to downgrade to the front of the property. The width of the trench will be 1 1/2 foot in order to compensate for the 4 inch pipe. The width of the pipe used will depend on the amount of water that accumulates to the specific area.
When trenching, attempt to salvage as much grass as possible in order to reuse it once the project is completed. The
depth of the trench will also depend on whether or not you will be using gravel as a filler in which case we did both. Since this project will also include installing fencing, the use of gravel up to a certain area was practical due to heavy traffic usage. Keep in mind that simply trenching an area will not simply suffice, the water must flow. One way to accomplish this is by using a 1/2 inch clear tubing. Use any type of anchor on one end, and let the gravity of the water level in the tube direct you to the necessary depth.
When selecting the tubing, you have the option of obtaining one that already comes with a wrap to filter out the dirt, however, from previous experience it is best to simply use landscape cloth to line the surrounding area. Also, the amount of holes that come with the tubing are generally not enough for adequate absorption. I recommend using the circular saw and create additional openings on top approximately 3 inches in length, 6 inches apart.
Though the customer obtained Pea Gravel as a partial filler, I would recommend at least a 1 inch size rock be used because Pea Gravel tends to compact with the dirt too easily, not allowing adequate water flow. The amount of drainage hole boxes will depend also on the amount of cumulative water for the area.
Though Catch Basins are used in drainage projects, they are not always recommended. The reason for that is that the water flow stops at the basin, not allowing the proper drainage. The water will stagnate in that area, creating mosquito nesting grounds. It is best to use large River Rocks at the exit point. This option will not only allow better flow but it also creates a landscape focal point in the yard.
This project took several days to complete due to heavy rains within that period. While digging the trench, we discovered another drainage pipe which had been installed, however, was not situated in the proper place. Prior to starting your trenching, take the time to observe where the water is stagnating. After the space is dry, outline the area before you forget what you observed during the rains. There is nothing more frustrating than to having to trench twice because the drainage was not in the proper place. The estimated material cost for this project was $375.