Project and methods for calculating storm sewers. Calculation of storm sewers: examples
Storm sewer is a system of water collectors, pipes, channels and collectors necessary to collect rainwater flowing from roofs and areas with impervious coatings. As with the construction of any other communication system, at the first stage of work, you need to draw up a project taking into account the requirements of SNiP.
At the design stage, the type of drainage system will be determined, the layout of the channels will be drawn up, the required diameter of the pipes will be calculated, the place of water discharge and the location of water intake points will be determined. A storm sewer project drawn up taking into account the requirements of SNiP will help you navigate the following points:
- What materials will need to be purchased?
- What should be the diameter and footage of the pipes?
- How will the installation work go?
- What will be the duration of the work?
- Will special equipment be required?
Ultimately, on the basis of the project, an estimate of the costs that construction will require can be drawn up.
Types of storm sewers
Before you begin to perform calculations, you should decide on the type of storm sewer. Advice! Despite the fact that the deep drainage system is often built in parallel, according to the requirements of SNiP, they should not be combined. They are placed in parallel, one above the other, while the storm system should be above the drainage system.
Types of storm drains according to the method of water drainage
There are three types of drainage systems for rainfall water:
- Closed drains. This is the most difficult option, for its implementation you need to perform a serious hydraulic calculation in order to choose the right pipe diameter. Water in this case is collected in special collections - storm water inlets, trays. Then the collected moisture enters the pipe system, through which they move by gravity or with the help of pumping stations. Water enters the collectors, from where it is discharged outside the site, an example of a possible outlet direction is reservoirs, ravines or drainage installations.
Advice! Closed-type storm sewers using large-diameter pipes are most often installed on city streets or in industrial enterprises. But sometimes it is this type of drainage that is best suited for private areas. The most striking example of the expediency of such a choice is that the site has a large area.
- Open drains. This option, on the contrary, is the simplest. In this case, the moisture is collected and removed by means of a system of trays installed in ditches dug with an inclination towards the collector. Trays from above are covered with decorative removable lattices.
- Mixed sewers. This option for arranging the system provides for the installation of elements of both types mentioned above. Mixed conduits are built to reduce the cost of building closed systems.
If it is planned to build a closed or mixed type system, then pipes with a diameter of 100 to 150 mm are used for private buildings. You can more accurately determine the diameter of the pipes by calculating, taking into account correction factors. When performing calculations, not only the diameter is taken into account, but also the level of slope of the pipes to ensure the optimal flow rate.
Types of storm drains by type of drainage system
There are two types of system arrangement:
- Spot water collection. It is carried out by installing local storm water inlets connected by pipes into a single network. It is necessary to plan the installation of fence points in problem areas, for example, under drainpipes and in lowlands on the territory of home ownership.
- Linear collection of water. This option is suitable for collecting moisture from large areas, an example of such areas is paved areas, concrete paths, etc.
Storm sewer design
Residential development projects always include a part dedicated to the construction of a linear sewer. But the owners of private plots, as a rule, have to take care of the construction of drainage systems on their own.
When constructing communications such as storm sewers, it is better to entrust the calculation of the main indicators to specialists, since they are produced according to rather complex formulas and require knowledge of the requirements of SNiP.
Regulations
When drawing up a project, one should strictly adhere to building and sanitary rules. So, if the calculation is carried out 2.04.03-85 is the main document.
The procedure for drafting projects
As a rule, the development of project documentation is entrusted to specialized organizations that have permission to perform such work. To start drafting a project, specialists need to obtain the following information:
- Topographical plan of the area where the storm water will be built.
- Data on the nature of soils, that is, the results of a geological study of the site.
- Territory development plan.
- Specification for connection to centralized systems, if such connections are implied.
- Desired methods for organizing the collection and disposal of water, determined by customers.
Based on the collected information, a technical task is drawn up, according to which the project is then developed, taking into account local conditions and the requirements of SNiP.
What is included in the finished project?
When the design work is completed, the customer receives a document, which includes the following sections:
- Common data.
- Schematic diagrams of sewer networks.
- Site plan indicating the locations of the system elements.
- Detailed equipment specification.
- Estimate, that is, the calculation of the budget for the construction of the system.
In fact, a well-designed project is not just an example of calculating storm sewers, but a clear, detailed and step-by-step installation instruction. The design process requires special knowledge, experience and punctuality. Therefore, work should be entrusted only to competent specialists.
Design is the most important stage in the construction of communication systems, including the construction of storm sewers. When building capital houses, it is advisable to entrust this process to competent design companies, since without special knowledge and without taking into account the requirements of SNiP, it is impossible to complete a competent project.
Storm sewage is a rather complex engineering structure, including storm water inlets, distribution wells, pipes and other necessary elements. Installation of such a system can be done independently. But the drafting of a stormwater project is only possible for specialists with the appropriate specialized education.
There are several important points to consider in the project such as uninterrupted and long service life of the entire system, the safety of footpaths and access roads, ensuring high-quality drainage from the foundations of buildings. A well-designed storm drain will help collect and remove the entire volume of precipitation from the site, that is, it will save the owners from problems with rainwater and melting snow.
Sewerage, designed to drain melt and rainwater, is of two types:
- Point provides collection of water from the roofs of buildings. Its main elements are rain inlets located directly under the downpipes. All catchment points are equipped with special sedimentation tanks for sand (sand traps) and are interconnected by a single highway. Such a sewer is a relatively inexpensive engineering structure that can cope with the removal of water from roofs and yards.
- Linear - a more complex type of sewer designed to collect water from the entire site. The system includes a network of ground and underground drains located along the perimeter of the site, along the footpaths and the yard. Usually, water from drainage systems placed along the foundation or protecting the garden and garden beds is discharged into the common collector of a linear storm.
According to the method of water drainage, stormwater is divided into: 
- For closed systems consisting of storm water inlets, flumes, a pipeline and a collector that opens into a ravine or reservoir. This is an ideal solution for draining streets, industrial sites and suburban areas with a large area.
- On open systems that collect water through trays and deliver it to collectors. The trays are covered with shaped gratings on top, which perfectly complement the landscape design and provide protection from debris. Such systems are mounted in small private areas.
- For mixed-type drainage systems - hybrid systems that include elements of closed and open systems. They are built most often to save the family budget. Outdoor elements are easier to install and cost less.
When you need a storm
The arrangement of storm sewers is directly related to the climatic features and the condition of the soil in a particular area. The stronger the area is moistened, the more acute the need for installation of a storm drain.
Factors indicating the need for water drainage: 
- regularly falling heavy atmospheric precipitation (torrential rains, heavy snow);
- high groundwater level;
- flooding of basements and cellars in the spring;
- the appearance of dampness on the walls and foundation (the appearance of mold, cracks);
- damage to paths and courtyards due to rain and snowmelt;
- slow drying of the soil (stagnation of water in puddles).
Design features
Any sewage system must comply with the technical requirements displayed in a special document - SNiP. This also applies to rainfall. The project is drawn up taking into account all the technical requirements of SNiP. In the future, it is necessary to strictly adhere to the project documentation, which will indicate the slope angles of the trays and the pipeline, the length of the communication, the building materials, equipment and tools necessary for the work.
For an accurate calculation you will need: 
- Get data on the average annual rainfall. The necessary information will be provided by the local weather service.
- Specify the area of drains. For this, the area of \u200b\u200bthe roof and the entire territory is calculated (if not only the yard is drained).
- Determine the quality of the soil. Sand and sandy loam perfectly absorb moisture, which cannot be said about loam and stony soils. Also, absorption slows down the presence of plants on the site - the root system contributes to the runoff of water, but prevents its rapid absorption.
- Find out the location of other communications (main sewerage, water supply, drains).
- An important indicator is the freezing point of the soil. If the pipes are laid below this point, the sewer will function without interruption even in winter.
The problem with soil freezing can be solved in a more modern way. For this, pipes are not dug deep, but under them is laid 
electric cable for heating. However, such a system will cost the owners a fairly substantial amount - having saved on earthworks, they will have to pay increased amounts of payments for electricity in winter.
It should be noted that the SNiP contains all the formulas necessary for carrying out calculations, taking into account the type of drainage system, the diameter and material of the pipes. The finished project must be approved by the supervisory authorities!
It is preferable to contact a licensed design organization, which will quickly and efficiently prepare all the necessary documentation, as well as coordinate the project in all instances without the participation of the owners.
Mounting process
The stormwater device from scratch includes the following steps: 
- Holders for gutters are fixed on the roof at a distance of 80-90 centimeters from each other. A slope of two millimeters is observed for each running meter of the gutter.
- Places for funnels are marked in the gutters. The finished hole is 10 centimeters. A funnel is inserted into it. The open ends of the gutters are closed with plugs.
- Then the gutters are placed in the holders, joining the segments with the help of connecting elements and sealant.
- Angled elbows are attached to the funnels, which ensure the outflow of water into drains placed vertically on the walls of the building.
- Drainpipes are attached to the walls with clamps. The distance from the drain to the wall should not be less than 10 centimeters!
- Drain elbows are mounted to the lower edges of the drains. The distance from the knee to the ground is 30 centimeters. Under each drain elbow there is a separate storm water inlet.
- Stormwater mains are laid in already prepared trenches with a sand cushion at the bottom 10-15 centimeters thick. For trays and storm water inlets, shallow ditches are dug. At the same time, collectors and manholes are being built.
- All trays and gutters are provided with sand traps. After that, with the help of knees, they are connected to the main drain, located below the freezing point of the soil. The tightness of all connections is strictly observed.
- The common one is discharged into the collector (additional filters, for example, sorption filters, can be installed in front of it).
- From the collector, water enters a storage well, from which an emergency drain is provided through a special pipe led into a ravine, a nearby reservoir or city sewer. Also, pumping water can be carried out manually, using a pump. In this case, a water discharge pipe is not needed.
After installation, the performance of the system is checked. To do this, water is poured into the storm water inlet. After that, the trays are closed with protective gratings, and the pipes are covered with soil.
Necessary tools
To carry out the work you will need: 
- bayonet and shovel shovel for excavation of soil from trenches and pits for wells and collectors;
- hacksaw for cutting plastic pipes;
- wrenches (adjustable and wrench);
- screwdriver;
- file for polishing pipe sections.
Materials used:
- plastic pipes;
- trays, funnels and grates (required for installation of an open drainage system);
- manholes made of plastic or concrete rings for their construction;
- rainwater inlets, sand traps and filters (if the water will be used for watering the garden and contains harmful impurities).
- cleaning the protective gratings of ground elements from large debris (branches, foliage, etc.);
- removal of sediment from sand traps;
- cleaning gutters around the perimeter of the roof.
It is also necessary to pay special attention to the efficiency of the storm drain. If water stagnation or poor drainage is noted, the reason 
lies in the clogging of the pipeline located underground. Required to solve the problem.
Flushing of the sewerage is carried out through manholes or collectors. Specialists use special water pumps equipped with a long hose with a nozzle nozzle. High pressure water flushes out debris and frees the pipeline.
Such emergency flushing is required only in case of non-compliance with the basic rules of operation:
- in case of untimely cleaning of gratings and sand traps;
- or in the absence of filters and sand traps in the system.
First and foremost: the key to the development of an economically viable and technically competent storm sewer project (as, indeed, any other project) is a correctly drawn up Terms of Reference. An unaccounted nuance or an error made in the preparation of the TOR usually leads to additional costs and loss of time for both the contractor and the customer of the project. Be careful and do not hesitate to use the advice of specialists even at this initial stage. Flotenk specialists will be happy to advise you on all issues.
Next, it is necessary to calculate the amount of wastewater for which networks will be designed and the parameters of surface runoff treatment facilities and sewage pumping stations will be calculated. In this case, it will be necessary to refer to the tabular and "local" geodetic and meteorological characteristics. Calculation is the foundation of a typical project storm sewer.
In outline, a typical storm sewer project can be imagined as:
Drawing up a structural diagram is the basis of the project.
Calculation of the number and type of water collectors: storm wells or collectors. Also, depending on the location of these elements, their design is selected.
Based on the drawn up structural diagram, linked to the plan, the footage of the drainage pipeline and / or storm trays is calculated. This takes into account the depth of the pipeline, the distance from the catchment point to the drainage well and the slope.
The needs for shut-off, control and connecting fittings, the number and location of manholes, and, of course, stormwater treatment plants are taken into account.
The equipment is placed on plans, profiles of sewerage networks, equipment specifications, wiring diagrams are drawn up.
Some examples of our projects:
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The development of a storm sewer project in full is a serious job, which should involve specialists with sufficient experience in the field of design.
A competent storm sewer project will allow you to easily pass the approval of project documentation in the supervisory authorities, carry out construction on time, save you from penalties from regulatory authorities and, in the future, close the issue of collecting and discharging surface wastewater for many years.
Storm sewage is one of the most important systems for equipping a residential area, which, unfortunately, many owners simply forget about or treat it too lightly. And it is completely in vain - the hopes that rain or melt water will go away by itself often lead to the gradual swamping of the territory, to the destruction or failure of the laid paths and platforms, to the erosion and erosion of the structures of the foundations of the erected buildings, waterlogging of their walls and other negative consequences.
Storm sewage includes many different elements that are responsible for a specific area of water collection, for several such areas, or for the entire system as a whole - these are storm water inlets, pipes, wells, collectors. In order for them to be able to cope with their task, their parameters must correspond to the expected volumes of water. And when planning a system, the calculator for calculating the volume of stormwater, offered to the reader's attention, may be useful.
Below, under the calculator, a brief explanation of how it works will be given.
