How to deal with groundwater at the site

Recommendation points

• The reason for the rise and appearance of groundwater
• Symptomatic treatment: pumping, drainage, water drainage
• Groundwater pumping
• Surface drainage
• Reclamation activities
• How to prevent the accumulation of groundwater in the basement
• Reliable waterproofing of the base of buildings
• Drainage of groundwater from the building using deep drainage
• Protection of wells and wells from groundwater
• Eliminate Soil Soaking Problems

This article will focus on groundwater and the consequences of its occurrence. We will tell you about the most effective methods of dealing with this problem and will help you to competently organize land reclamation work. By following the advice in this article, you can completely eliminate the problem of damp basements and damp soil..

The reason for the rise and appearance of groundwater

The main source of groundwater is atmospheric precipitation, the volume of which increases sharply in the spring due to melted snow. Influence is not only the volume of precipitation, but also the terrain, the structural features of the waterproof layers, which do not repeat the soil surface, but, on the contrary, form many irregularities and depressions.

Water naturally passes through the top layer of the soil, reaches the first water-resistant layer (clay) and flows through it to the lowest point, forming areas of high moisture.

Groundwater rises high when the volume of the supplied water exceeds the capacity of the gaps: the upper aquifers are flooded, the passable soil sections are clogged.

Waterlogged soil poses a serious threat to the foundations of buildings:

1. The support resistance of soil layers subject to severe water erosion deteriorates sharply, floaters and subsidence appear, heaving becomes uneven.
2. Calcium compounds are gradually washed out of wet concrete, giving it strength.
3. High humidity is an ideal condition for the development of mold and moss, which gives rise to biological erosion of concrete massifs.

Stagnant wetting of the soil is no less dangerous for the fertile soil layer, because nutrients are intensively dissolved and washed out of it, the black soil is compacted. Suffering from severe wetness and rotting tree roots.

Symptomatic treatment: pumping, drainage, water drainage

Groundwater pumping

Groundwater that accumulates in technical cavities: basements, wells, drain pits, can be removed from the site using a drainage pump.

The power of the drainage pump must be selected at the rate of 0.5-1.3 m³ from one square meter of the area of ​​the drained area. This means that from the basement of the house 100 m² will have to pump out from 50 to 130 m³ water provided there is no incoming moisture.

Surface drainage

It is implemented in an open trench up to 1.5 meters deep, the task of which is to overcome the folds of the waterproof layer and direct the water towards the natural slope of the soil. In this way, it is possible to drain very large-scale territories, up to several quarters of a cottage village, so often the owners of the sites unite and hire equipment for digging trenches.

Reclamation activities

Typically flood-prone areas are located on the outskirts of settlements in natural lowlands and folds. In these cases, the water flows down a natural slope, and the trench is directed towards the bottom point and has a constant depth.

In cases when it is far to the border of the settlement or the landscape of the area excludes the discharge of water into the lowland, the same drainage ditch is used, but already having an artificial slope. Through it, water is diverted from an area oversaturated with moisture to a less saturated one, where it is absorbed into the soil as it flows.

Such activities cannot be performed without geodetic leveling; geological surveys are also required to extract the detailed topography of the impermeable layer. Add to this the cost of mechanized excavation and under-road trench passes.

Cost table for groundwater drainage along an artificial slope

Topographic survey of the area M 1: 500	500-600 rubles / 0.01 ha
Soil sounding and topographic mapping of the waterproof layer	from 2000 rubles / 1 ha
Drafting a drainage system	from 20,000 rubles.
Excavator services	1000-1500 rubles / 1 hour (5-12 meters)
Superintendent services	RUB 3000 / shift (8 hours)
The cost of embedded pipes	1100-1300 rub. for 1 running. m

The device of such a trench will allow to drain up to hundreds of sites and the same amount will be able to bring its drainage to the general discharge system. So if you divide the costs by the total number of participants, then the amount will be quite lifting. The budget can be cut by doing earthwork manually, for example, by members of the dacha cooperative.

Such measures give only a general improvement in the geological situation, local flooding will have to be eliminated by additional measures.

How to prevent the accumulation of groundwater in the basement

Buildings with their mass, albeit insignificantly, but sink waterproof layers, which is why a depression is formed into which water flows from the adjacent territory. And even if the soil remains relatively dry, rainfall flows towards the building instead of uniform infiltration into the soil..

There are two main methods of protecting the foundation from getting wet.

Reliable waterproofing of the base of buildings

At the construction stage, a gluing or coating external waterproofing is applied. It can also be carried out on the constructed object, alternately digging the entire perimeter with a trench about 1 meter wide. This is advisable if there is a need to strengthen the foundation of the building. For buildings without a basement, such a measure remains the only possible.

If the building has a basement and access to the inner walls of the foundation, the injection waterproofing method is applied. It consists in perforating the solid wall without violating its basic technical qualities. A penetrating composition is poured into the holes made. The water repellent crystallizes in the pores and almost completely eliminates the ability of concrete to absorb water.

Drainage of groundwater from the building using deep drainage

Perforated drainage pipes are buried along the perimeter of the building, at the joints of which inspection or technical wells are installed. Around the elements of the drainage system, a lining of hygroscopic material – crushed stone or expanded clay is laid. Water, seeping into the openings of the pipes, flows through them to the wells, then through pipes of larger diameter to the collector and the central drain. Drainage is carried out into a drainage trench, water can also be evenly discharged onto a dry soil area.

Secondary measures for drainage of water from the foundation – surface drainage with protected trays and a blind area.

Both of these methods are advisable to apply not only to the foundations of buildings, but also to the entire site as a whole..

Calculation of the cost of arranging deep drainage

Earthworks: digging trenches around the house, fastening and backfilling	RUB 1500-2200 / 1 running m around the perimeter (2 m3 soil)
Bulk materials for paving (crushed stone, expanded clay)	600-700 rubles / 1 lin. m around the perimeter (0.5 m3)
Drainage pipes with perforation	170-500 rubles / 1 running m (diameter from 110 to 200 mm)
Drainage wells	5000-1000 rub. per point
External waterproofing of the foundation	RUB 300-650 for 1 m2
Foundation injection waterproofing	from 2000 rubles / 1 running m around the perimeter (including work)

Protection of wells and wells from groundwater

Groundwater, in addition to being capable of damaging pipes and concrete rings, can significantly affect the quality of borehole and well drinking water. The ground water contains a large amount of dissolved active substances that can accelerate the rate of metal corrosion by an order of magnitude, as well as small silty and mechanical impurities that strongly pollute water.

There is a whole range of measures that allows you to maintain the purity of water and extend the life of the equipment:

1. Wells are protected with caissons and conductors. They are mounted to the depth of the lower boundary of the waterproof layer, thereby blocking the path of groundwater. The cost of installing a caisson or a conductor ranges from 5 to 11 thousand rubles per meter of depth.
2. To protect the wells, external waterproofing is used, concrete rings are restored, and the joints between them are sealed. Protection of wells of medium diameter (60-100 cm) from the inside will cost from 2.5 to 4 thousand per meter. External waterproofing will not only keep the water clean, but also prevent the rings from collapsing. Price increases by the cost of excavation.
3. In some cases, digging in the immediate vicinity of an accumulation well for collecting and pumping groundwater helps. Due to this, you can drain the nearby area and get an additional source of process water.
4. You can also arrange a security lock around the well. A simple filling of the dome from compacted clay will divert the top water and groundwater from the adjacent territory from the well.

Eliminate Soil Soaking Problems

After abundant moisture, the soil loses its fertility, its structure is disturbed. It is strictly forbidden to apply mineral fertilizers to such areas, and the dosage of organic fertilizers should be increased to 5-7 kg per 1 m² in year. It will be possible to completely restore the fertile layer only in 3-4 years. At the same time, it is necessary to treat the soil with chemicals that block the development of harmful microflora supplied with fertilizers..

The structure of the soil is restored by loosening twice a year, sowing the area with plants with a fibrous root system. For example, you can sow a plot for one summer with hybrid varieties of wheat or rye, bred specifically for irrigated fields, this will also speed up the process of restoring fertility..

For a price of about 500-700 rubles per kg, you can buy earthworm-miners. An increase in their population in the soil will give very good results in restoring looseness and normal nutrient content..