Below, we look at some of the differences between a Water Siphon System as opposed to Conventional Drainage methods. If you’d like further information and would like to speak to us directly, please get in touch.
A Siphon drainage system can access and manage the water table far deeper than conventional drainage.
- It can be used to just drain the water table lower
- It can be used to collect the water in the water table
– This could be for water purification or processing
– “polluted” water filtered by the soil is able to be returned to natural waterways
– nitrate rich groundwater can be collected and denitrified
– this could be for water re-use - Groundwater can be collected and stored in ponds or tanks e.g. stock watering
- A siphon drain system could be used as a “spring tap” to collect groundwater in a hillside and gravity feed it down to lower land or a storage facility
- Nutrient rich groundwater can be collected and re-irrigated onto the surface plants e.g. treating land like the hydroponic system
Conventional drainage requires considerable earthworks and excavation to make the trenches and/or lay the pipelines.
Siphon drainage has comparatively tiny amounts of earthworks – just making the holes in the ground for the spear straws to reach into the water table.
Conventional drainage needs to be dug to below the level of the water table.
Therefore, this is usually done on the dry season. It’s depth determines the maximum level of drainage.
- Only the tips of the spear straws need to go below the level of the water table
- All of the rest of the system can be completely above ground. It can also be buried if preferred
- Therefore, it’s very easy to access for maintenance, or to add extensions and tributaries to it – like a tree – with main trunk, limbs, branches and twigs
- Extensions and improvements can be easily added in the wet season
Conventional drainage flows down a slope
The drain must have a fall on it for the water to flow. To drain against the contour requires deeper excavations etc. The price of trenching gets much higher and more difficult as it gets deeper.
Conventional drainage earthworks can be limited by obstacles such as rock, sand, hills, forests, buildings, or other infrastructures.
Siphon drains can travel over obstacles, around buildings, through forests etc – just like pressurised water systems. It can also go under a river, over a bridge, through a building.
Conventional drains are cut and laid to a designed fall rate
- For example, 1:100 or 1:200 for a larger diameter pipe
- The flow rate is set by this angle
- Only if the pipe is 100% full will it be at its maximum flow
- Note – large open drains that are clear of weeds etc have very little fall loss
The siphon drainage system flow rate varies according to total height difference between the start and finish
- If the water level builds up at the start, increasing the head, then the flow rate will increase accordingly
- The flow rate decreases as the head difference decreases
- The water level between the start and the finish will naturally equalise to be virtually identical
- It levels just the same as a water hose level
- Because a siphon drain system is made from smooth pipe and is completely closed with no air etc there is extremely little loss as it works like a hose water level
Conventional drainage only works to the depth of the drain.
To drain the water table lower the entire length of the drain needs to be dug that much deeper. Making deeper drains becomes proportionally much more expensive.
Siphon drainage works to the depth of the tip of the spear straw; only the tip of the spear is deep into the ground and water table. Therefore, to increase the drainage depth there is a relatively very small increase in cost.
To increase the overall drainage effect – only the spear hole and spear assembly needs to be made deeper and the outlet level might need to be lowered as well
See – ” lower point to drain to” in diagram.
Conventional drainage spreads the wet-ness along its lower length.
The effect is draining and maybe dispersing water into dryer areas along its path.
Siphon drainage extracts the water and bypasses it without wetting surrounding land.
A conventional open drain is vulnerable to becoming blocked with weeds or silting up.
It may need regular cleaning to maintain its efficiency. Also, it may be a physical barrier to cross for machines and livestock. However, open drains do have a capacity to cope with very large peak flows of water.
Conventional drainage is “on” all the time.
It removes any water that enters the network. They can be blocked by shutters or weirs but the water accumulates at the lowest end – saturating the land upstream.
Siphon Drainage System’s can be turned on or off; draining or retaining.
Individual branches of a siphon drainage layout can be isolated or focused upon.
Lower point to drain to
Conventional drains and siphon drains rely upon a lower point to drain to
Both conventional and siphon drainage systems can drain into a open drain, pond, river, man-made sump or drainage pond. In areas where there is little fall it’s possible to make an artificial low point to drain to.
A sealed sump can be inserted into the land and the water drained into it. If it’s not possible to drain directly from here, a submersible lifting pump can be used to pump the water out and keep the water level low in the sump thereby accelerating the drainage rate.
The same method can be used for managing the water table height in the field. By adjusting the cut in/cut out height of the submersible pump in the sump, the level of the water in the field is affected.
Adjusting a siphon drains outlet level is very simple therefore, water table management is easily achieved.
Refer to our diagram of a cross-section of the sump that also has a submersible pump and float switch. Or it could actually be one siphon system in (yellow) and the green pipe line could be another siphon system out (without the pump).
A conventional drains flow rate is dependent on the fall
The siphon drain system also relies on the fall however, because it is a closed pipe system, a boosting axial flow pump can be added anywhere along the pipeline to increase the flow rate and extraction rate. That said, it is best added on the upside rather than the downside if possible.
Conventional drains and siphon drain systems can be combined very well
The conventional drain system can collect the excess water in the fields and bring it to a central location.
The siphon drain system can extract that water to another location where it is either stored or discharged.
A siphoning drainage system can collect nutrient rich water in the water table.
This water can be naturally collected and stored for re- irrigating or processing.
The siphoning drainage system can be used to filter dirty water
Dirty or contaminated water can be dispersed on the surface. The siphon system has the ability to collect that water again after it has soaked through a great deal of soil.