Stephen Charles Landscape and Contract Gardner’s have been involved with designing and installing irrigation systems for over 20 years. Many projects involve irrigation systems for new buildings,
We approach garden irrigation from the gardener’s point of view i.e. as a means of promoting the initial establishment and subsequent healthy growth of plants. Our irrigation designs and specifications reflect this. Whilst pressures, volumes and flow rates all have there place and indeed we use all of these in our calculations combined they represent about 50% of the design the rest comes for an empirical knowledge of garden plants, shrubs and trees which can only be gained by experience.
On many projects where we have taken over the landscape maintenance where irrigation has been previously installed by the priority has been seen as the volume of water which can be applied /dumped on the poor unsuspecting plants in as short a time as possible. We have seen cases where the plants were all stunted by the irrigation continually ‘chopping there heads off’. If you have such a system don’t worry as we can fix it for a fraction of the cost of the installation. We find generally all the individual components of the system are perfectly good it just the design which is the problem.
Irrigation has a number of benefits when considering landscaping on a site
Tree & Shrub plantings will establish more quickly
Increased vegetative growth will give a “mature” appearance in a shorter time
As mature specimens are under greater levels of stress regular wateringreduces the failure rate and will allow specimens to establish more quickly
Quantity of water can be controlled to allow complete penetration on rooting zone this encourages the roots to go down into the soil and not up seeking water & again this helps plants to establish
The water is distributedto the areas where it is most needed and therefore less wasted water
Flexible delivery watering may be done easily 4 times a day if required or once per week in a different part of the garden
New lawns will establish quicker
Lawns will remain green even in the driest periods
Regular watering promotes the growthfiner grasses thus producing a finer more dense sward
A Healthy lawn Reduces the need forlawn weed killers
Promotes the regeneration of heavily traffic area of lawn
The capital cost of an irrigation system, can be repaid in just a couple of years when compared to the cost of hand watering
Watering can be done at night where there is none of the inconvenience of having hoses and vehicles trailing about during the day
Where there is little depth of soil, such as in planters or roof terraces pots hanging baskets and where external works have been “landscaped” by adeveloper/building contractor i.e. little depth for soil but lots of building waste, then irrigation is essential. Not only is hand watering prohibitively expensive, it is never frequent enough to keep up with the evapo-transporation of the plants. Watering in these areas needs to be carried out two or even three times per day.
Irrigation system design
It is important to get advice on irrigation design early on in a project. Important factors to take into account include
The types of planting
The size of planting
The amount of soil the plants have available
The pressure and volume of the existing water supply
The level of sophistication of system required
Where the control equipment is located some way from the areas to be irrigated, the architect needs to consider how the pipe work will be routed
Location for water storage tanks, pumps and control equipment
Installation of an irrigation system is normally in two main phases commencing with the installation of the underground pipe work in M.D.P.E. pipe At this stage the pump and control equipment would normally be installed Indoors pipe work is normally routed in copper pipes. This then allows the pipes to be tested under pressure before back filling of trenches. Once the beds and soiling up has been completed the sprinklers and the drip irrigation is installed. The system would then be fully tested and commissioned.
Water delivery to plants s normally achieved either by:
Sprinklers which use spray nozzles to throw water over a relatively large area;
Drip Systems which use a number of drip nozzles mounted into a pipe to cover an area
Individual Drippers, which use individual nozzles to bring water to a single pot or hanging basket
Leaky hose system. Pours pipe allows water to soak gently into the surrounding soil
Generally speaking sprinkler systems consume far more water than drippers. Not only do they have greater flows and therefore need larger supply pipes and pumps, they are also more wasteful as the water droplets tend to evaporate when thrown into the air.
Lawns are not generally suited to watering by drip systems, as the underground pipe runs can get damaged when carrying out maintenance such as lawn spiking. In the UK, lawn areas are normally watered using popup sprinklers, the pipe work for these is deeper than for drip systems and therefore they are not affected by operations such as spiking. Popup sprinklers as the name suggests rise up from within the lawn when watering commences. Inside each sprinkler there is a gear drive which causes the sprinkler head to rotate back and forth. The arc of each sprinkler can be adjusted to anywhere between 30° and 360°.with a radius of between 3 and 33 yards dependent on model and water pressure. Once watering has finished they retract down below the turf level, making them virtually invisible. Larger models even have turf caps to make them completely invisible.
Sprinklers are spaced out to ensure a reasonable overlap between sprinklers. Windy sites need a greater overlap than sheltered positions as the wind will cause drifting.
Micro sprinklers used to water larger planters and beds. These are small sprinklers which are permanently sited in beds the heads are raised on a stem of approximately 9” high each sprinkler will be responsible for watering one or two plants. Each micro sprinkler is individually adjustable making it an extremely flexible system allowing different plants within a bed to receive different volumes of water. These water at relatively low pressure allowing water to be absorbed into the soil and minimizing water run off
Most modern drip systems use nozzles mounted ‘in-line’. This means that the pipe work is smooth, with each drip nozzle fitted inside the pipe. This has the advantage that there are no protruding parts to catch when laying the drip pipe (or be pulled of by vandals). Dripper spacing and outputs vary, however the most common output is 1/4Gal/h at 18 inch spacing.
On larger areas the trickle lines are laid out in a grid fashion, with each run 2 foot apart.
As well as being used on planted beds, lengths of drip line are often used in narrow planters to give an even distribution of water along the length.
Normally the drip lines are staked to the soil surface to prevent movement. If required they can be hidden under a mulch. Hiding the pipe away, however, can cause problems when weeding and forking as the contractor cannot see the pipe or any damage that is done. Burying the pipe underground is not recommended as root intrusion will block the nozzles. Under lawns drip pipes would also be damaged if the grass were spiked. If it is essential to bury the pipe special filters are available which add a chemical to kill any roots that intrude into the pipe.
Drip for Baskets
Drip systems use individual nozzles to bring water directly to each hanging basket or container. They are fitted with a stake to push into the compost. The emitter provides a steady dripping of water onto the compost.
Generally the pipe work down to each dripper is only ¼ inch in diameter, making it as unobtrusive as possible. The pipes are black colored to resist the effects of sunlight. Light colored or clear pipes are not recommended as they allow algae to grow inside the pipe. The slim pipe is then connected to a larger supply pipe which delivers the water to a number of drippers.
Trees have a high demand for water due to evapo-transporation with larger trees needing several hundred gallons on a hot dry day. In urban planting situations, the tree roots are severely restricted by root barriers and impervious paving. In addition, the soils the tree is planted in may be contaminated or of poor quality.
To provide a regular water supply a specialist Strata Root system is used, which provides air and water deep into the tree pit. Specially designed baffles in the tube force water into the soil at different levels. For large trees a 1 yard long Strata Root tube will be placed either side of the tree.
For smaller trees which only require irrigation to establish them, drip lines can be used, but they are less suitable for long term use as the water often stays near to the surface, discouraging the tree roots from developing at depth.
If necessary, nutrients can be fed through the system to ensure the trees remain healthy.
Rain Water Harvesting
Rain Water Harvesting is the economic way of capping a natural resource for uses such as watering
Rainwater is filtered by the collector unit to remove garden debris and other large particles
The settlement within the tank occurs creating a beneficial biological layer
The floating filter allows water to be drawn from the cleanest part of the tank
Water Qualit is maintained by the removal of organic matter and the continual introduction of oxygen from incomming water
No light enters the tank therfore the water does not discolour or become malodorous
Water can be stored for long periods
Rainwater is naturally 'soft' and chlorine free ideal for garden irrigation
Water can be used inside the house for flushing toilets and laundary
Stephen Charles Landscape and Contract Gardeners as well as designing irrigation systems and fixing other contractors systems we maintain irrigation systems. A typical maintenance schedule is shown below
A spring visit:
This is where after the winter the system is brought back into service. During this visit we will
Install new batteries in the water computer or controller and set up the program for the forthcoming season
Re fit any water computers or control equipment.
Turn on the water supply and re fill any tanks
Service and maintain any pumps
Clean and check all components of the watering system and rinse out any filters
Bring system up to pressure and check for leaks
Repair or replace any damaged or broken pipe worksprinklers or components up to a total value of £11.00 per visit
Provide an engineer for up to 1 hour per visit per system
Demonstrate system in operation
Clean around system remove any rubbish and leave in a tidy state.
Visits during the Growing Season
This is where adjustments may be required to ensure maximum watering efficiency
·Clean and check all components of the watering system and rinse out any filters
·Check the system for leaks
·Repair or replace any damaged or broken pipe worksprinklers or components up to a total value of £11.00 per visit
·Make adjustments required to allow for changes in vegetative growth
·Provide an engineer for up to 1 hour per visit per system
·Clean around system remove any rubbish and leave in a tidy state
An Autumn Visit
This is where the system is taken out of service for the winter.
Remove the computer from the tap, remove any batteries clear the program and leave with client for winter storage
Service and maintain any pumps
Drain down the system to prevent frost damage.
Clean around system remove any rubbish and leave in a tidy state