Do-it-yourself site drainage on clay soils

Content

1 When is drainage necessary?
2 Types of drainage systems
3 Construction of surface drainage
4 Deep drainage device
5 Drainage system maintenance

Excess moisture in the area of a country house can cause many problems. Constant dirt, crumbling foundations, flooded basements, and crop disease are all the result of high humidity. Drainage of the site, done according to all the rules, will help get rid of excess water and protect buildings from destruction.

When is drainage necessary?

Puddles on the site after rain and melting snow are not yet a reason to install a drainage system. It is necessary to understand when the soil itself is capable of absorbing water, and when it needs help. Drainage installation on the site is necessary in the following cases:

constantly flooded basement;
soil erosion, as evidenced by dips on the surface of the site;
in clayey soils, resulting in waterlogging of the area;
if there is a slope nearby from which water flows;
the site has no slope;
heaving of the soil, which leads to the appearance of cracks in buildings, distortion of door and window openings.

Types of drainage systems

Before making drainage on the site, you need to decide on the type of drainage system. There are two main drainage systems that perform the same function, but are used in different situations:

Superficial — designed to drain water that appears after rain or melting snow.
Deep – is established in areas with high deep water levels.

The surface drainage system is mainly arranged on clay soils and is divided into linear and point. Linear is a system of ditches and trays located with a slight slope towards the water collection point. To give an aesthetic appearance to the drainage system, the trays are covered with decorative grilles.

In a point drainage system, water is collected by water collectors located in places of greatest accumulation of moisture - under a stack of drainpipes, in low areas of the site, near a water supply located on the street. The water collectors are connected to each other by pipes through which water is discharged into a drainage well.

Construction of surface drainage

Do-it-yourself surface linear drainage on clay soils must begin after drawing up a plan that indicates the location and dimensions of trenches and other elements of the drainage system.

According to this plan, trenches are dug with a depth of 0.7 m, a width of 0.5 m and a wall slope of 30 degrees, which will prevent them from collapsing. All trenches are connected to one common one, which runs along the perimeter of the site and ends with a drainage well. The main advantage of the open drainage method is the simplicity of the system, which does not require large financial costs. Among the disadvantages, one can note the fragility of the structure - over time, the unreinforced walls crumble, and the drainage system ceases to function. In addition, the trenches have an unaesthetic appearance, which spoils the appearance of the site.

The problem of shedding can be solved by backfilling with crushed stone.The bottom of the trench is covered with a layer of coarse stone, and on top of it is a finer one. To avoid washing, the crushed stone backfill is covered with geotextile, on top of which a layer of turf is laid. This method worsens the throughput of surface linear drainage, but prevents the walls from collapsing, which significantly increases the service life of the system.

There is a more modern way of constructing linear drainage - a closed drainage system. The difference between this method is that the walls and bottom of the ditch are concreted and special trays are placed inside, covered with decorative grilles. The trays reliably protect the soil from sliding, and the gratings protect the channel from debris. The trays are laid with a slope necessary for the unhindered passage of water. In places where water is discharged, sand traps are installed to collect small debris. Making such a drainage system is more difficult than a trayless one, but its service life is much longer.

There is a wide selection of components for closed drainage systems on sale, made from a variety of materials: concrete, polymer concrete, plastic. The latter is the most popular due to its durability and light weight, which ensures maximum ease of installation.

Advice! For more efficient drainage, point and linear drainage systems should be combined.

Deep drainage device

The deep drainage system differs significantly from the surface one not only in its design, but also in its purpose. You cannot do without it in areas with a high level of groundwater and located in lowlands.For such a system to operate effectively, it must be located below the aquifer. Determining the depth on your own is quite a difficult task - this will require the help of a surveyor who will draw up a detailed diagram of the site with all the groundwater level marks.

The design of the deep system is a network of drainage pipes located in the ground and draining excess water from the soil into a drainage well. Moisture seeps inside due to many holes located along the entire length of the pipe. You can make the holes yourself or buy products with ready-made perforations. The following types of pipes are used for deep drainage:

asbestos-cement - obsolete material, gradually becoming a thing of the past;
ceramic – have a long service life and a high price;
plastic ones are by far the most popular because of their low cost and ease of working with them.

Advice! For deep drainage, it is better to use plastic pipes with oblong holes, which promote better water infiltration and are less susceptible to clogging. To avoid pushing through as a result of soil pressure, you should purchase plastic pipes with a corrugated surface.

Sequence of laying deep drainage:

Using a geodetic level, mark the area. If there is none, then during rain, monitor the direction of water flows and, according to observations, draw up a plan for the location of drainage channels.
According to the planned plan, dig a trench system. To check that they are positioned correctly, wait until it rains and make sure that the water does not stagnate anywhere. Once you are sure that everything is done correctly, you can continue working.
Lay geotextile tape along the entire length of the trench at the bottom.
Maintaining the slope, pour a layer of crushed stone on top of the geotextile.
Lay drainage pipes on top of the crushed stone bed. The connection of individual pipes into a single system is done using tees, crosses and inspection wells.
The end of the pipe, located at the lowest point of the site, is inserted into the drainage well.
Cover the sides and top of the drainage pipe with a layer of crushed stone. Do not use crushed limestone for backfill. As a result of exposure to moisture, it turns into a monolithic composition through which moisture cannot penetrate.
Wrap the pipe together with a layer of crushed stone in geotextile tape - this will prevent clay and sand from getting into the structure.
Fill the top with crushed stone or coarse sand 20 cm below ground level.
The remaining space is filled with soil located on the site.

To monitor the operation of the drainage system and clean it in case of clogging, it is necessary to install inspection wells at a distance of 35-50 m. If the system has many bends, then through one turn. Wells are constructed from reinforced concrete rings or polymer corrugated pipes of the required diameter and covered with decorative covers.

A properly designed and installed deep drainage system in accordance with all requirements can last more than half a century.

Drainage system maintenance

In order for the soil drainage system to function for a long time and properly, it requires regular maintenance:

Routine maintenance involves periodically cleaning the wells. The frequency of this procedure depends on the conditions in which the system is operated.
Cleaning drainage mechanically.Cleaning the surface drainage system is not particularly difficult and can be done independently. In the case of deep drainage, the situation is more complicated - you will need a special pneumatic installation with nozzles for removing deposits and crushing large elements. It is recommended to carry out such cleaning once every 3 years.
Hydrodynamic drainage cleaning. This method involves flushing pipes with a mixture of air and water supplied under pressure. The mixture is supplied alternately, first to one end of the pipe, located in the drainage well, then to the second, which is brought to the surface during the installation of the drainage system. Flushing is carried out by a pump and compressor supplying air under high pressure. Under the influence of the mixture, deposits are crushed and washed out. The frequency of hydrodynamic cleaning is once every 10 years.

Saving on cleaning may lead to disruption of the system and the need to replace some elements, which will ultimately lead to additional costs for materials and work. Proper operation will help maintain the system in working condition and extend its service life.