When building a house on a site with a high level of groundwater, drainages are laid, which protect the structure from spring flooding, soil erosion, destruction of the foundation blind area and flooding of basements. To minimize the cost of arranging the drainage system, drainage and storm sewers are laid in one trench.
Purpose of drainage and storm sewers
Storm rain collects melt and rainwater into gutters and rainwater inlets, then through a pipeline it drains the water into the wells. It connects the external drainage system and the underground wiring into one whole.
To drain the wetlands, drainage is used, which does not allow the level of groundwater to rise, diverting it using pipes perforated along the length into capturing wells. Taking into account the general focus of the problem - the removal of excess water - they combine drainage schemes in order to subsequently use natural resources competently, directing technical water, for example, to watering a garden or flower garden.
Sharing a trench does not mean pooling circuits. Drainage and rainfall in one pipe will overload the perforated drains in peak mode, which will not allow groundwater to be drained out in time and will cause flooding of the site.
The drainage piping can only be closed, since it is laid underground. Several conditions that determine the need for its installation:
- the aquifer lies close to the surface;
- according to its characteristics, the soil is clay or loam;
- the site is located in a zone of frequent floods;
- the foundation elevation is below ground level;
- construction is planned in the lowlands.
Drainage system elements:
- perforated geotextile pipes (drains) for collecting "excess" fluid;
- sedimentation tanks sand traps;
- piping made of plastic, asbestos-cement or ceramic pipes to drain collected water;
- inspection wells.
The pipes of both systems can be positioned in the same trench for easy installation and cost savings.
Storm and drainage combination
The task that is set for the builders is to drain the effluent according to autonomous schemes into one drainage well. For this, a nodal tee is used, which combines the external streams of rainwater with the drainage of groundwater.
Drains, buried around the site, collect the rising groundwater and are led through pipes into a well, from which they are pumped out and discharged to a designated place.
Usually, storm water is collected in a collector, which is located in the same trench with a drainage pipeline, from the collector, water enters the main network, then into a bypass well, from where it is also pumped out.
It is possible to connect the storm drain to the drain using a nodal tee to output the flow into one line in the direction of the common drainage well. Pipes are laid at a slope established by SNiP for sections of different sizes. For example, for Dm110 mm, the slope is 2 cm per linear meter.
Dual system installation rules
Before installation, design work is carried out with a topographic survey of the area. The throughput for pipelines is calculated, which should ensure the drainage of water in overload mode.
When bookmarking, you must follow the following guidelines:
- Arrangement of drainages requires significant investments. Incorrect calculations will lead to additional costs. It is quite difficult to restore a broken system, it is easier to build a new one.
- The combination of rainfall and drainage in one trench is permissible, but they are located at different depths. A well for collecting water can be shared.
- The depth of the ditch is made taking into account the layer of crushed stone and sand, which should provide better water filtration.
- Perforated drains are laid below the storm pipe.
- Place the pipes at some distance from each other. This protects the drainage system from overloading in the event of damage to the storm.
- The maximum installation depth of a 700 mm collector is 120 cm.
Effective operation of the combined circuit will preserve the integrity of the foundation and prevent flooding. The money that would have been spent on the arrangement of both drainage systems and waterproofing will be halved.
Operation and maintenance
Without preventive cleaning, rainfall and drainage are silted up, clogged with sand and clay. Inspections are carried out during the dry autumn period or at the beginning of winter. The main task: to ensure the integrity of the drainage system and maintain its capacity.
Pipeline cleaning is performed using a conventional hose and clean water, which is supplied under high pressure. The mud rushes into the well, from where it needs to be scooped out, then the walls and bottom must be scrubbed by hand. Trays, gutters and rainwater collection ditches are also washed to remove dirt.
Regular cleaning will guarantee the stable operation of the storm sewer and drainage system.
