Guidelines documentation hydraulics

Surface flow is formed by rain and melt waters as well as the water after street irrigation and cleaning. Herewith the rain and melt water sediments in cities form over 2 mm flow because there are large size waterproof coatings (yard, street carriageways coatings, house roofing).

This method is based on SNiP 2.04.03-85

Hydraulic design of drainage system should be performed separately for each plot and area, such designs should best be carried out by the drainage and sewage system design specialists. Gidrolica® surface drainage systems are intended for water collection and expulsion from paving surfaces as well as of building and structure basements. Our company specialists can give You the recommendations on selection of Gidrolica® drainage systems.

Let’s consider one of the simplified design variants. In order to make a proper choice of drainage gutter it is necessary to calculate the amount of precipitations falling on the nominal area. Q l/s water flow from the area is calculated as follows:

Q = q₂₀ × F × ϕ

where:
q₂₀ – precipitation rate (l/sec) per Ha (Ha = 10 000 ²);
F – nominal area of flow in m²;
ϕ – coating surface saturation coefficient;

Example:
It is necessary to select Gidrolica® drainage gutter
Type of coating (ϕ): asphalt – 0,95 (see Surface flow coefficient table).
Precipitation rate (q₂₀) –Moscow region – 80 (l/sec) per Ha (see Precipitation rate table).

Area – F = 20×30/10000 = 0,06 (Ha)
Load class according to EN1433 – C250

Rainfall

Region	q₂₀
Moscow	80
Krasnodar	100
Nizhniy Novgorod	90
Samara	70
Soratovv	70
Volgograd	60
Rostov-on-Don	90
Sankt-Petersburg	60
Kazan	80

Flow surface coefficient

Surface type	Coefficient ϕ
Roofing	1
Asphalt concrete pavement	0,95
Cement concrete pavement	0,85
Macadam	0,25 — 0,6
Gravel pavement	0,15 — 0,3
Grass area depending on soil	0,05 — 0,35

By putting the data we have into the formula, we can obtain the precipitation amount in this region which should be collected.

Q = 80 × 0,06 × 0,95 = 4,56 (l/sec)

According to the value obtained, Q (flow capacity) we select the drainage gutter according to the catalogue, in accordance with the load class. In our case gutters DN 100, cl. С250 (see General characteristics of gutters) suit.

General characteristics of gutters

Art.	Load class	Name	DN, мм	Length, mm L	Width, mm C	Height, mm H	Вес, kg	Проходное сечение, см²	Channel throughput capability, l/sec
Art.	Load class	Name	DN, мм	Length, mm L	Width, mm C	Height, mm H	Вес, kg	Проходное сечение, см²	Slope 0,5%
801	A, B, C	Drainage channel LV-10.14,5.12 — plastic	DN 100	1000	145	120	1,4	93,3	5,12
406	A, B, C	Drainage channel LV-10.16.18,2 — concrete	DN 100	1000	160	182	36	136	5,2
903	A, B, C	Drainage channel LV-10.14.13 — poly-concrete	DN 100	1000	140	125	14	92,1	5,01
700	A, B, C	Drainage channel LV-10.14.13 — poly-sand	DN 100	1000	140	130	12,8	102	5,69

For the effective water outflow to sewage systems it is necessary to take into account the flow capacity of pipes (see Flow capacity of pipes at different slopes, l/sec).

Type of basement for pipes should be set depending on the bearing capacity of soils and loads (see SNiP 2.04.03-85)

Flow capacity of pipes at different slopes, l/sec

pipe diameter, mm	Slope
pipe diameter, mm	0,05	0,1	0,15	0,2	0,3	0,5	1
110	4,37	6,19	7,58	8,75	10,71	13,83	19,56
160	9,72	13,8	16,84	19,44	23,81	30,74	43,5
200	16,92	24,0	29,39	33,94	41,57	53,66	75,9

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