Landscape infrastructure: drainage and automatic irrigation systems

The role of infrastructure in a landscape project

Plant selection and design tend to get the attention, but the long-term success of a landscape project depends heavily on what happens underground. Poor drainage leads to root rot, and a poorly designed irrigation system leads to both wasted water and uneven plant growth. This article covers the technical components of infrastructure work, from soil preparation to winterisation.

At Taxus Fidancılık, we plan infrastructure work as a distinct project stage within our landscape installation and periodic maintenance services; assessing soil and drainage conditions before planting is part of our standard process.

Soil preparation

How well drainage and irrigation perform depends first on the soil’s physical structure. In compacted, low-permeability soil, neither drainage lines nor irrigation water will deliver the expected performance.

Soil preparation steps

1. Measure the existing soil’s infiltration rate with a simple percolation test
2. Loosen compacted layers to a depth of 30-40 cm
3. Improve heavy clay soils by working in organic matter and sand
4. Clear coarse stone and debris before planting
5. Establish the slope direction so surface water is guided toward a drainage point

A percolation test can be done simply: dig a hole 30 cm deep, fill it with water, and time how long it takes to fully drain. Draining in under an hour indicates fast drainage; taking more than six hours points to a serious drainage problem.

Drainage types and selection criteria

The drainage system used in a landscape project is selected based on the site’s slope, soil structure, and where the water will ultimately be discharged.

Common drainage types

Drainage type	Working principle	Suitable use
Surface drainage (by slope)	Natural flow of water along the slope	Large lawns, gently sloping sites
French drain (perforated pipe)	Perforated pipe plus gravel backfill collecting groundwater	Areas with a high water table
Point drainage (channel grate)	Water collected at specific points and carried off by a line	Hardscape, terraces, entrance areas
Dry well	Gravel-filled pit letting water percolate slowly into the soil	Limited-area gardens with no discharge point

A French drain is particularly useful at tree bases and in areas with a high water table. Perforated PVC pipe is wrapped in geotextile fabric and placed in gravel backfill; this keeps soil particles from clogging the pipe’s perforations.

French drain installation steps

1. Dig a trench 40-60 cm deep along the line where water pooling has been observed
2. Lay fine gravel at the trench base with a slight slope (about 1-2%)
3. Place the geotextile-wrapped perforated pipe in the trench
4. Backfill over the pipe with gravel and close it up with the fabric
5. Cover the surface with soil or turf and connect it to a discharge point

Automatic irrigation systems: drip and rotor

Automatic irrigation systems offer clear advantages over manual watering in terms of water efficiency and plant health. System choice depends on the type of planting.

Drip irrigation

Suited to shrub groups, border planting and tree bases. Water is delivered directly to the root zone at low flow, which reduces surface evaporation and weed growth. Emitter spacing is typically 30-50 cm, with flow rates between 2-8 litres per hour depending on plant type.

Rotor and sprinkler irrigation

Preferred for large lawn areas. Rotor heads rotate to water a wide area gradually, while fixed or fan-pattern sprinkler heads cover smaller areas. Spacing between heads should be planned head-to-head according to the manufacturer’s stated coverage radius; otherwise watering will not be even.

System type	Typical flow	Coverage	Suitable planting
Drip line	2-8 litres/hour (per emitter)	Point-based	Shrubs, tree bases, border planting
Sprinkler (fixed head)	10-20 mm/hour	3-5 m radius	Small-medium lawn areas
Rotor head	8-15 mm/hour	6-12 m radius	Large lawn areas

Hydraulic design measurements

An irrigation system works correctly only when the hydraulic calculations behind it are correct. The system needs to be split into zones (valve groups) based on available water pressure and flow capacity; otherwise pressure drops at the far ends of the lines.

Key measurements in system design

1. Measure mainline water pressure (bar) and flow capacity (litres/minute)
2. Split each valve group’s total flow so it does not exceed mainline capacity
3. Select pipe diameter to limit pressure loss given line length and flow
4. Plan head-to-head spacing between sprinkler/rotor heads according to coverage radius
5. Position valve boxes at points that allow easy maintenance access

As a general reference, head-to-head spacing for rotor heads on a lawn is set equal to the head’s coverage radius; this ensures the zone between two heads receives adequate water from both.

Winterisation

In regions with freezing winters, preparing the irrigation line and equipment for winter directly affects the system’s lifespan. Neglected winterisation can lead to cracked pipes and valve failures.

Winterisation steps

1. Shut off the irrigation system’s main water supply
2. Drain water from the lines with compressed air (blow-out)
3. Wrap above-ground valves and control units with insulation
4. Switch the control panel to winter mode or disconnect its power
5. Run a line pressure test before bringing the system back online in spring

What to watch during ongoing maintenance

Even a correctly installed infrastructure can lose efficiency over time without regular checks. Reviewing drainage and irrigation systems at set intervals during the operating period both preserves water efficiency and catches potential faults before they grow.

Periodic checks on drainage lines

French drain inlets can gradually clog with leaves, soil or root growth. Cleaning inlet points at least once a year, particularly after autumn leaf fall, is recommended. For point drainage with channel grates, sediment buildup beneath the grate should be cleared regularly; otherwise surface water discharge slows during periods of heavy rainfall.

Monitoring flow and pressure in the irrigation system

Over time, emitters can develop limescale or clogging, and heads can wear down. This causes some plants to receive too little water while others are overwatered. Running each valve group at the start and midpoint of the season and visually checking flow and coverage catches these imbalances early.

Updating the system as plants develop

As plants grow, their root zone and shading change, which means an irrigation volume calculated correctly at installation can become insufficient or excessive a few years later. In areas planted with fast-growing species groups especially, reviewing the irrigation programme every 2-3 years and updating emitter flow or run times where needed is advisable.

Suggested check frequency during operation

Check item	Recommended frequency	Purpose
French drain inlet cleaning	Once a year (after autumn)	Preventing blockages
Valve group flow/coverage check	Start and midpoint of season	Catching uneven watering
Channel grate sediment clearing	Every 3-4 months	Keeping surface drainage flowing
Irrigation programme review	Every 2-3 years	Updating for plant development

Conclusion

Drainage and irrigation infrastructure form the unseen but decisive layer of a landscape project. When correct soil preparation, the right drainage type, hydraulically sound irrigation design and regular winterisation are applied together, water use becomes efficient and plant growth becomes predictable. For your landscape infrastructure projects, reach us at +90 539 438 29 87 or info@taxustr.com.