Step 4.1.1 - What planning issues do I need to consider?

The planning considerations focus on the following sub-questions:

Step - 4.1.1.1 - What land area and shape can I irrigate with border-check systems?
Step - 4.1.1.2 - Can undulating land be irrigated?
Step - 4.1.1.3 - What soil types are suitable for border-check?
Step - 4.1.1.4 - What are the water supply and quality issues?
Step - 4.1.1.5 - What catchment issues do I need to consider?

Step - 4.1.1.1 - What land area and shape can I irrigate with border-check systems?

Border-check can be used to irrigate areas of virtually any shape or size. However, rectangular paddock shapes are preferred, and are most common. The dimensions, direction and slope of bays and the overall layout should be considered in the context of a Whole Farm Plan. Sections of the farm (such as a paddock) should not be considered in isolation. Although generally the overall layout is determined by topography and is relatively straightforward, compromises are often needed to achieve the layout that best suits the needs of farm operations, such as the location of feed pads, laneways, dairies, etc.

A whole farm plan integrates all components of the farm irrigation systems

Step - 4.1.1.2 - Can undulating land be irrigated?

Border-check irrigation is best suited to relatively flat land. Three issues affect the suitability of undulating land for border-check irrigation – the slope, the depth of the topsoil, and the volume of earthmoving needed to achieve the desired layout:

• Slope – Slopes of 1:100 to 1:800 can be used to irrigate perennial pasture, with perhaps 1:300 to 1:600 being an optimum. For more information see the Agnote “Border-check Irrigation Design”.
• Depth of topsoil - Removal of the topsoil is a serious problem associated with landforming. It results in exposure of low fertility sub-soils with poor soil structure and texture. Where shallow topsoils (as in much of the northern Victorian irrigation areas) are landformed, they should be stripped, temporarily stockpiled and replaced after landforming.
• Earthmoving – Slopes can be changed, minor undulations can be smoothed out, and cross slope can be removed with earthmoving equipment. However, this is expensive, and an economic assessment is needed to determine if a particular option is feasible.

You may choose to undertake relatively expensive earthworks to achieve the desired layout, or you may decide against developing a particular section of the farm to border-check irrigation. Alternative irrigation systems might be better suited to such areas or they may be left dry, perhaps to grow trees, or for habitat/biodiversity purposes.


Step - 4.1.1.3 - What soil types are suitable for border-check?

Soil type is an important factor where border-check irrigation is considered. In particular the infiltration and drainage characteristics of the soil are important. Infiltration – On most Shepparton Irrigation Region (SIR) soils, infiltration is typically rapid as the soil wets up (the crack-fill component), slowing to an on-going constant rate (the final infiltration rate) after ten to twenty minutes. While the crack-fill is largely dependent on the soil moisture deficit (the "dryness”) of the soil at the time of irrigation, the soil type largely determines the final infiltration rate. “Light” soils (coarser textured) tend to have higher final infiltration rates compared to “heavy” (finer textured, or clayey) soils. The design of a border-check irrigation systems can make some allowance for final infiltration rates; lighter soils need faster waterings and thus shorter bays, higher flow rates and/or steeper slopes. However, the sandy (“light”) soils in the SIR tend to have high final infiltration rates and this normally results in excessive infiltration, and poor irrigation efficiencies. These soils should be avoided for border-check irrigation development. For more information, see the Agnote “Border-check Irrigation Design” and Step 2.3.7.2.

Some soils are not suitable for border-check irrigation

Drainage – The heavier (clayey) soils tend to be flatter and situated lower in the landscape, resulting in poorer drainage characteristics. While such soils can be successfully irrigated by border-check irrigation (subject to drainage and the above comments on slope), they tend not to be as productive as “medium” textured soils.

For information on soil types in the Shepparton Irrigation Region, go to Step 2.2.1


Step - 4.1.1.4 - What are the water supply and quality issues?

As with any irrigation development, a water entitlement and water use licence is needed. Information about the water requirements of perennial pasture is presented in Step 2.3.1.

• Flow rate – Border-check systems can be designed to suit a large range of flow rates (see the Agnote “Border-check Irrigation Design”). High flow rates enable more land to be irrigated in a given time, minimising labour or automation costs.
• Water quality – The main water quality issue is salinity (electrical conductivity, or EC), and this is normally only a concern if ground water (or in some cases surface drainage water) is being used. Contact your local DPI office for information on required shandy ratios of good-quality surface water (from the channel) with poorer quality water from the reuse system, drainage diversion, or ground water.

For further information, the Groundwater Note “Using saline groundwater in the Shepparton Irrigation Region”, or contact DPI at Tatura


Step - 4.1.1.5 - What catchment issues do I need to consider?

In addition to the irrigation requirements of the site there are a number of off-farm issues that have to be considered before irrigation development can commence. These issues are discussed in Step 2.2.11. Further information relevant to border-check irrigation is given here:

• Earthworks – Border-check irrigation development typically involves significant earthworks that require a local government planning permit. These permits ensure that regional drainage is not restricted or significantly changed by the proposed works, potentially impacting upon others. To avoid having to apply for a planning permit every time you want to implement part of your whole farm plan, your council can certify the Whole Farm Plan, and you can implement it over several years. For more information, contact your local DPI office.
• Remnant vegetation – A local government planning permit is required to remove remnant native vegetation. This isn’t automatic – in some cases a permit may not be given. If a permit is issued, it is likely that a condition of the permit will be to plant “compensatory” plantings of suitable species. For more information, contact your council or the Benalla or Bendigo DSE office.

With border-check irrigation it is often possible to develop the area while leaving valuable stands of remnant vegetation intact. However, for trees within the irrigated area (grey box in particular), water needs to be kept away from at least the area within the drip line of the trees; otherwise they are likely to die as a result of waterlogging.

• Farm dams – Drainage reuse storages are an important component of border-check irrigation systems. New drainage reuse or irrigation storages must comply with the Victorian farm dams legislation.

Typically, you can have up to one megalitre of storage capacity for each 10 ha of irrigated land. If you want to store more than this, you need to provide water entitlement, either by purchasing water or by transferring some of your existing water entitlement. For more information, contact your local Rural Water Authority office.

Further issues discussed in Step 2.2.11 which may be relevant in some situations are:

• New Irrigation Development; and
• Farm Effluent Management.

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