Stormwater is the water draining off a site from the rain that falls on the roof and land, and everything it carries with it. The soil, organic matter, litter, fertilisers from gardens and oil residues from driveways it carries can pollute downstream waterways. Rainwater refers only to the rain that falls on the roof, which is usually cleaner and so rainwater filtration system is very important. However, stormwater can be a valuable resources. Reusing stormwater can save potable water and reduce downstream environmental impacts. Poorly managed stormwater management can cause problems on and off site through erosion and the transportation of nutrients, chemical pollutants, litter and sediments to our waterways. Well-managed stormwater can replace imported water for uses where high quality water is not required, such as garden watering. There are many products available in the market for stormwater filtration system such like gross pollutant trap, oil grease trap, hydrodynamic advanced vortex separator etc. By installing a proper stormwater filtration system, it helps to prevent clogging of the drain which causes flooding. As more and more developments are taking place around us, the congestion of the constructions debris and silts are flowing to the drain causing flash flood in most of the major cities around the world. Despite the continuous development and expansion of our drainage system in the country, we believe the problem should be rectified and prevented at the source.
Stormwater management in Malaysia is essentially about flood mitigation by managing the surface run off during heavy downpour. It can also be applied in rural areas (to harvest precipitation water), but is essential in urban areas where run-off cannot infiltrate because the surfaces are impermeable. Traditional storm water management was mainly to drain high peak flows away. Unfortunately, this only dislocates high water loads and causing flash floods in urban areas. Modern approaches aim to rebuild the natural water cycle, example to store runoff water (retention basins) for a certain time, to recharge ground water (infiltration basins) and to use the collected water for landscape irrigation or daily cleaning. A rainwater filtration system is usually put in place before the water is channelled into the storm water storage tanks with the purpose of preventing gross pollutant debris from entering these underground storm water tanks.
We at Myhomepalm are able to provide stormwater management solution in Malaysia. With our trained consultants and engineers, we can design the storm water management system to suit our customer needs.
THE OSD TANK CHARACTERISTIC :-
Vertical soil pressure
The covering soil layers/soil fill cover produce vertical soil pressure. This is linear and depends on the installation depth /height of the fill cover and the density of the chosen material. The vertical soil pressure is normally estimated to be around 20 kN/m² per metre of fill cover.
Vertical loads
The vertical load comprises the traffic load and soil pressure as described above. The sum of the two loads is therefore dependent on the installation depth. This limits the maximum permitted fill cover on top of the infiltration elements.
The approved long-term vertical load for the overall system with a lifetime of 50 years is 59 kN/m² including safety factor of 2.0. Both the approved vertical loads and the vertical loads actually present limit the installation window of the ditch elements with the minimum and maximum installation depth, the installation window for the infiltration tunnel/twin infiltration tunnel can be calculated in the same way.
Vertical and lateral acceptance limits vs loads factored :-
Load |
Longest Creep tests |
Extrapolated limits |
Vertical |
Rupture 1,864 hours + creep > 7,100 hours |
138 kN/m2 |
Vertical factored |
1.3 material factor and 1.1 temperature correlation. |
96.5 kN/m2 |
Lateral |
Rupture > 6,000 hours + longer creep test |
35 kN/m2 |
Lateral |
1.3 material factor and 1.1 temperature correlation. |
24.5 kN/m2 |
Horizontal load
The angle of friction has an important influence on the horizontal loading. Part of this vertical load is converted into a horizontal load by the internal rigidity of the filler material.
The horizontal load is also dependent on the height of the fill cover, i.e. the installation depth, and limits the installation window for the infiltration ditch elements.
Class |
Pedestrian load |
Car |
Lorry 12 |
Lorry 30 |
Lorry 40 |
Lorry 60 |
Installation depth (max) (m) ɸ = 20° |
3.00 |
3.00 |
3.00 |
2.75 |
2.50 |
2.25 |
Installation depth (max) (m) ɸ = 30° |
4.25 |
4.25 |
4.25 |
3.75 |
3.75 |
3.25 |
Installation depth (max) (m) ɸ = 40° |
5.00 |
5.00 |
5.00 |
5.00 |
5.00 |
5.00 |
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