9     CHAPTER:  Fencing

9.1     General

As a general rule it is best practice to exlucde stock from the creek at all times.  Stock in waterways usually create the following problems:

  • Pollute the water
  • Increas erosion
  • Eat the vegetation that is serving other purposes such as helping minimise erosion, providing habitate, protecting stock and crops etc.
  • Drink the dirty water

There are always exception and some of them are listed here:

  • Access water for drinking where there is no off stream watering
  • Cross a creek to pasture on the otherside
  • Crash grazing in an emergency.

The concern with crash grazing is that the farmers rather than using the creek as an emergency option allows stock to graze the rehabilitation site regularly.  With regular or even occasional grazing ground covers and naturally regenerating seedlings, both of which are critial to the long term sustainablity of  rehabilitation project will be crushed or eaten.

9.2     Location

One of the most contentious issues when deciding to carryout a creek rehabilitation project is where the fence should be located in relation to the Lip of the channel.  Understandably the landholder, often a farmer, is keen to loose as little farming land as possible while the rehabilittion expert understands that for nearly every oucome that he is designing for, erosion control, biodiviersity, water quality etc that the wider the Verge, the area between the Lip of the creek and the fence, the better.

Given past experience it seems that an absolute minimum average width is an average of 20 meters, the width of a single large gum tree, with an occasional minimum of 15 meters, ususually at the head of a gully.  

Setbacks from the Lip less than those recommended above simply do not provide sufficient space for enough plants to establish themselves to holt ongoing erosion , create windbreaks or generate sufficient space for natural regeneration.

From a farmers perspective it can often be a false ecconomy to put fences too close to an ereoding creek bank.  If there is not enough space to establish a protective buffer it is likely that the erosion will continue until the fence falls in and the fence has to be moved, and rebuilt, loosing the farmer even more land.

For a truly sustainable Verge which can act as a wildlife corridor while at the same time having a good chance of establishing a healthy and balanced vegetation cover requires an average distance of 50m between the Lip of the channel and the fence line

9.3     Gates and maintenace

It is important to have at least one wide gate on either side of a creek providing access for farm vehicles.  It is critical for cost effective maintenance that farm vehicles have access to the Verge of a rehabilitation site.  Direct vehicle access to the verge improves weed and vermin control, access to potential farm forrestry products such as fire wood and recreational use.  Even if the landholder can not see an immediate advantage to having vehicle access to the rehabilitation site history has shown the it nearly always becomes an advantage.

Ease of maintanence is one of the critical components of any rehabilitation project, both for the success of the project and the long term benefit of the landholder.  To facilitate a successful maintenance program it is highly desirable to leave a 3- 4m wide path clear of plantings along the inside, the side closest to the creek, of the fence.  This access track on the inside of the fence can be kept open by slashing the grass once or twice a year.  The fence line access track can provide the following benefits:

  • Vehicle access all along the length of the rehabilitation project
  • The ability to use a weed spray hose and reel without getting caught on the fence
  • Ability to easily visually inspect the fence on both sides
  • Minimise branch drop on the fence
  • Plants growing in a rehabilitation site will typically create a strip of less successful pasture or crop next to them by restricting the amount of ground  moisture they have access to.  If this strip is located where the access track is then the farmer is not losing a great deal of pasture anyway and the grass grownign on the access track will be easier to maintain.

9.4     Different types of fence

There are a range of different fencing types depending on the result the landholder is wanting to achieve.  Where ever there is going to be stock adjascent to a rehabilitation project there will need to be a fence to exclude them from the waterway.  If a fence is too be built in some cases the landholder may consider, usually at an additional cost considering a non standard option.  

One particular concern which often arises when fences are being planned near a creek is the damage that can be done to the fence when the creek floods.  Flooding creeks will often be carrying large amounts of debrie such as tree truncks and branches.  The debrie carried by the flood material can quickly build up along fence lines until the pressure of the water pushes the fence over.  Unfortunately in situations where flooding is likely to cause fence damage none of the available solutions have proven to be 100% effective. Some of the options for flood prone fences are included below.


Standard

This is the most common type of fencing. For cattle 7 wires and one electric wire for cattle and horses 1200mm high or ringlock (squares approx 300mm square )for sheep and goats. (In a flood rignlock fences are more likely to be knocked over dure to the increased likeliehood of debrie building up against the fence. Posts on this type of fence are usually 125mm in diameter.

Electric fence

An electric tape fence has often been tried in cases where damaging floods are expected.  While the fence does in fact take very little damage and can be reset very quickly there are downsides to this option.  The major problem with electric tape fences is that they are very unreliable.  It takes the electricity supply to only be cut for a short time before stock become aware there is no longer a barrier and they quickly push into the rehabilitation site.  Once in the rehabilitation site stock can quickly do signigicant damage particularly to relatively young vegetation.

Fold down fences

In flood prone areas fold down fences have been trialled and are still used in a number of areas.  The down side with this type of fence is the initial additional cost and the difficulty in restablishing the fence after the flood.  The reason for the difficulty reestablishing the fences is that there is often a large amount of debrie that is lying and and is tangled up in the fence.  By the time the landholder has found the time to clear the fence and get it upright nearby stock have had plenty of time to damage the formerly protected vegetation.

Robust fencing

Another option for landholders considering their options in flood prone areas and that is to make a standard fence more robust.  In this instance the fence wires are the same as for a standard fence but the posts and end assemblies are both larger and set more deeply in the ground.  While individual wires may be snapped by debrie in a flood as the structure of the fence is more likely to be intact the fence can be made opporational again relatively cheaply and quickly.

Rbbit proof

5 wires, posts 125 in diameter plus 900mm wide gal chicken wire 600mm up the fence and 300mm flat on the ground facing the creek.

Kangaroo and wallaby proof

Deer fence consists of a square mesh with a height of either 1500mm or 1900mm high with posts 125mm - 150mm in diameter.