About
The land where the Arboretum is being created was originally a marsh. Local folk law has it that in the late 1800’s a single plough line was dragged through the marsh to begin the process of draining it for agricultural land. As is common in much of Australia, that original drainage line quickly began to erode, and then kept on eroding. By the early 2000’s the original plough line had turned into a badly eroded creek chocked with weeds, forming an approximately 10m deep 40m wide scar running through the landscape.
The Creek Design
Undertaking the rehabilitation of the waterway that had replaced the marsh was to prove particularly difficult. The main reason for this was that the waterway more closely resembled eroded drain than any type of waterway that had existed prior to white settlement. Without a naturally existing template which could be followed it became necessary to in essence create a new type of waterway. This new type of waterway would aim to replicate many of the attributes of natural waterways while at the same time making allowance for a combination of conditions that would rarely if ever be encountered in a natural/normal creek or marsh.
Some of the key elements that define this new type of waterway can include:
Aggressive ongoing erosion both of the bed and the banks
Elevated nutrient inputs
Significant levels of incision below pre-existing ground level
Weed infestation
Greatly increased water velocities
Rapidly changing, variable physical conditions such as steep bare clay banks and high in steam sediment loads
The name allocated to this new type of waterway was a “Running Marsh”. The aim of a Running Marsh is to combine the attributes of the pre existing marsh as far as possible; ie. slowing water speed, minimizing erosion, trapping sediment, filtering water etc. while at the same time adding the attributes of more traditional creek structures. The resulting rehabilitation project focused on maximizing the use of local species of rush, reed and sedge to slow the water speed within the low flow channel and thus recreating as many marsh like attributes as possible to the waterway.
In short, the creek project has involved trialling a combination of contemporary best practice techniques selected both from the theory of both creek and marsh rehabilitation. The result of this combination of techniques would seem to offer the best chance of creating a new type of stable, sustainable, biodiversity rich waterway, in short a Running Marsh.
The development and progress of the Running Marsh rehabilitation project can be followed in more detail under the Creek Diary section of this website.