3    CHAPTER: Changing Attitudes 

3.1    Introduction

This Chapter highlights areas of creek rehabilitation has changes over recent years.  As there are currently no guidelines to best practice each rehabilitation project has been done.  The methedologies of each project have varried depending on the level of funding and the relative experience of those involved in leading the project.  This chapater starts by giving a summary of the types of method that have been commonly used in the past and in many cases ar still used today.  The Chapter goes on to identify a range of areas where contemporary thinking is influencing a new generation of rehabilitation project.

This Chapter gives an overview of recent changes only, to obtain a more detailed description of the changes the reader can visit the relavent Chapter nominated at the end of each sub heading.

Over recent years it has become increasingly clear that a number of common creek rehabilitation practices have not provided the best outcomes possible and new methodologies are now recommended.  

The most up to date practices in creek rehabilitation are included throughout this book however it is worth elaborating on a number of cases where contempory creek rehabilitation practices differ significantly to those that have been used previously

3.2    A typical rehabilitation project from 1990 - 2010

The points below are indicative only.  Many if not most projects will not have used all these points but most projects will have used some of them.

  • An individual project is a part of a larger community driven project covering an area which relates to a particular creek or catchment.
  • While there is an over arching plan there is no rehabilitation plan specific to each individual project.
  • The project is directed by a knowledgable Landcare member, Landcare co-ordinator or government department facilitator.  The project director, who may or may not have a formal education in environmental rehabilitation is responsible for choosing and ordering the plant species to be used.  The project director also oversees most of the other elements of the project including weed control and negotiating the location of fencing with the landholder.
  • The project director is not working to documented best practice guide lines
  • The plant species ordered often contain a high proportion of tree species particularly eucalypts.  
  • The fence is errected often not much more than 10 meters from the Lip of the creek channel.
  • The weeds are dealt with by a contractor, often the one who provides the cheapest quote.
  • Where planting is carried out by a contractor the contractor employed is often paid an amount per plant planted and so speed and planting close together is in the interests of the contractor. (Also if there is a high failure rate it is not uncommon for the same contractor to be employed to replant an area.)
  • In preporation for planting the seedlings are mixed together so as to ensure a random mix of species across the site.
  • Planting can often be as close as 1 to 2 meters apart irrespective of species
  • Milk cartons or plastic sleeves are placed over the trees to protect them from hungry or destructive wildlife
  • There is little follow up spraying or watering in the year following planting


3.3    Using a creek rehabilitation plan 

While many rehabilitataion project have a land holder agreement in place before works begin this is not the same as a rehabiltiation plan.

The cost of a typical rehabilitation project is normally in the thousands of dollars.  If this sort of investment is to be made it is reasonable to expect a plan to be in place before the works begin.  

A rehabilitation plan can be anything from a many page document to a couple of A4 sheets.  The key information that it should contain

For more detailed information see Chapter xxxx

3.4    The Use of trees

In the past trees such as eucalypt have been planted in all parts of a creek from the verge to the low flow channel.  Experience is now showing that the planting of trees in both the high flow channel and the low flow channel should be extemely limited.  The reason for this is that native trees, with the exception of some melalucas, have a corse root structure which is not suited to resisising high speed water flow.  As a result native trees are often undercut by creek flow.  Trees which get undercut will eventually collapse into the creek taking a sizable chunk of the creek bank with them and where the tree once stood there often remain a destabilised, steep area of bank, which is particularly vulnerable to even more erosion. 

Another problem with using trees in the creek channel proper is that trees, eucalypts in particular can shade out, out compete and or poison other plants that live beneath them.  The bare earth beneath a eucalypt becomes simply another area that is vulnerable to future.

The ideal place for trees is on the creek verge where their extensive root systems can stablise the land beside the creek while at the same time take up excess moisture which can lead to areas of the verge calving or slumping into the channel.

For more detailed information see Chapter xxxx.


3.5    Focus on the LFC

In the past the focus of revegetaion has primarily been on the verge and on the bank in the high flow channel.  It is now clear that the majority of erosion is initiated by the flow of water in the low flow channel.  The low flow channel is where the water flows most of the time and it is here that it causes erosion directly or by undercutting the bank causes bank failure.

It is therefore a priority to protect the low flow channel from the erosive force of th water where possilbe. This can be done in some instances with hard works, see chapter xxxx or more commonly through the use of appropriate vegetation.  The type of vegetation that is most appropriate for the low flow channel are reeds, rushes, sedges, paperbarks or tea tree.  All these types of plant have members of their family which have matted roots and have evolved to resists high flow events and retain the integrity of the surface that they are planted into.

For more detailed information see Chapter xxxx.

3.6    The Spacing of plants

In the past all plants were typically planted 2-3 meters apart, irrespective of whether they were gum trees which would grow to have a cannopy of over 20 meters or small shrub which would have a cannopy of 2 meters.  

It is now considerd desirable vary plant spacing depending on the type of plant.  While it is not practicle to plant every plant species a different distance apart, it is possible to use some basic variations in plant spacing.  While circumstances will differ from site to site it is reasonable ot use the following rule of thumb:

Large trees: 5 meters apart
Shrubs and small trees: 2 meters apart
Grassy plants: 1 meter apart

One of the key goals when considering spacing is to maximise the ability of each clump of plants to compete with other weeds species.  One of the best way for clumps of plants to compete with weeds is for them to grow closely enough together that their cannopies merge and create a condition of cannopy lock which denies the weed species the light they need to grow.  

For more detailed information see Chapter xxxx.