Healing the land: techniques for managing erosion

Community spirit, professional expertise and practical demonstrations were a feature of this erosion and revegetation workshop. Guest speakers David Hilhorst and Andy Taylor from South East Local Land Services and Scott Soper led an inspiring and educational day.

One of our participants Chris Curtis has kindly agreed to allow us to publish his notes and photographs from the day – see the link below.

Erosion workshop notes PDF

This wattle is providing protection to help other plant species to grow

Here are more ideas and strategies from the workshop.

Pioneer plants such as wattle add nitrogen to the soil and improve soil fertility and structure. You can use branches from these plants (preferably with seed attached) and lay them over bare ground to create a nursery for seeds and/or or tube stock.

Locally grown small trees including wattles, kunzea and tea tree can be lopped and placed strategically on an eroded gully floor, the branches can be bundled and pegged creating a brush raft. The raft areas catch sediment that can be direct seeded using native grasses, sedges and rushes.

Look for wet patches above and below small erosion head cuts and use these sites for revegetation using locally sourced plants. Use bendy plants that slow the speed of the water including Juncus species, Carex appressa and Lomandra species. Trees that grow thick trunks should be avoided in confined gully beds and streams because tree trunks can deflect flood waters into banks and exacerbate the erosion problem.

Protect your soil from erosion is by maintaining 70- 80% ground cover in your paddocks and by limiting stock access to dams and dam spill ways. Erosion can be caused by overland flows from vegetation removal, dams, roads and gullies and by subsurface water movement. You can use simple clues to help you read your land, for example, are larger trees dying in patches? This could indicate that salinity is a problem. The eroded site at the property we visited was most likely being impacted by saline ground water which we learned also affects the water quality in the dam.

Mapping shallow ground water with an electrical conductivity survey gives an insight into the depth of the water resource and the salinity of an area. Windellama Landcare owns electrical conductivity (EC) mapping equipment and it can be hired for use by property owners and contractors. You should seek advice from South East Local Land Services to help you plan your erosion control work and EC mapping – Contact your Local Land Services office.

Learning how to do a simple sodicity test
Sodic soil demonstration by Andy Taylor and David Hilhorst

 

 

 

 

 

 

 

An example of sodic soil at the site in Bungendore

Eroded patches of sodic soils in gullies look like candle wax or stalactites. You can do a simple sodicity test using a small clod of soil and a clear dish. If area around the clod becomes cloudy, this indicates that the soil is sodic and might be highly erosive.  Soil sampling of your farm could help you decide if you should be planting salt tolerant species at an eroded site.

Saline and Sodic Soils – the Difference video

Weirs, rock structures and rock/wire mesh weirs are all examples of “controlled activities” that may require a permit. Contact the Office of Water for advice about building structures including dams in drainage lines. As a general principle, water should always be returned to the same drainage line not diverted to another site. Before undertaking major works in water courses and gullies it is wise to check that your contractor has sought the correct approvals.

Contact a water regulatory officer as listed on the Office of Water website, call the licensing information on 1800 353 104 or email information@water.nsw.gov.au for more information.

Stabilising an erosion site above a dam. The hessian rolls were filled with mulch and compost and seeded with grass seed.

Jute or hessian can be used on bare eroded sites to create zones where vegetation can be established. ‘Burritos’ can be made by wrapping jute or hessian fabric around a mixture of forest mulch and compost which can then be laid on the contour and held in place using wire pegs. Mulched areas can then be seeded with a soil conservation grass mix or local native grasses. Once micro climates have been established other plants can be encouraged to grow using the brush raft technique described above.

 

Weeds such as blackberry and serrated tussock can be used as a resource to help provide mulch, organic matter and plant cover at eroded sites if they are already growing there. It is important though to manage weeds to prevent flowering or setting seed by cutting, spraying or manual removal. Chip and spray the weeds or cut the canes and leave them in situ on the gully floor or bank, this slows the flow of water and traps sediment. The area can be then planted with desirable plants and grasses. The thorny plants can act as protection for new plants during establishment. Continual monitoring of weed prone sites is important.

The SIX Maps website can be used to  work out the size of the catchment for an erosion head cut. For example, using SIX Maps, Andy Taylor estimated that for 1 in 50 year high rainfall events, the gully on this farm would have one tonne of water per second flowing over it. That is equivalent to one intermediate bulk container (IBC)/second. Estimating catchment size, soil testing and electrical conductivity testing are just some of the tools that can be used when planning erosion control measures.

Further information and resources

Gully Erosion Assessment and Control Guide

The Farm Dam Handbook

Rural Living Guide – A guide for Rural Landholders in the South East

Guide to Managing Ground Cover – MLA

DPI Erosion Website

Grassland Flora – a field guide for the Southern Tablelands

Native tree and shrub resources

SIX Maps – mapping tool

This event was made possible with funding and in-kind support from South East Local Land Services.

The Cutting Edge: Chainsaw Workshop

The weekend of the 24 & 25 March was a ‘cut above’ the rest of our workshops for 27 participants from the region.

Workshop trainer Barry Aitchison shared with us some chainsaw related statistics. National Coronial Information Service data shows at least 99 deaths occurred in Australia between 2000 and 2016 as a result of chainsaw use and tree felling (Source ABC News). According to Barry in 2014 there were over 60 accidents from chainsaw use requiring at least 66 stitches in NSW hospitals. Having worked in the industry for over 33 years Barry believes that the main cause of injury is apathy, complacency and fatigue as most accidents occur in the afternoon.

So what are Barry’s top five tips for safe chainsaw operation and maintenance?

  1. Safety is the number one priority – invest in a good chainsaw and safety equipment. Including chainsaw chaps, helmet, eye and ear protection, gloves, close fitting clothing and lace up boots if possible. A dust mask is also useful to prevent dust and fungi from the wood dust getting into your respiratory system. When in the bush consider using a hi-vis safety vest. Always be aware of other people around you by keeping them in your line of sight.
  2. Chainsaw fuel once mixed does not last forever. At the beginning of the season empty the old fuel from the chainsaw and put in fresh fuel. Use a high octane fuel and a special synthetic chainsaw oil. If the chainsaw is not working check the fuel, spark plug and chainsaw air cleaner first. For new chains soak the chain in bar oil for two hours so the reservoirs in the chain fill up with oil to lubricate the bar.
  3. Use a safety chain with a low profile, this will help prevent kickback. Different chainsaws models require different chains. The chain, bar and sprocket must match. The chain can not be pulled in the reverse direction if the chain and sprocket don’t match. The chain can be fitted the wrong way, so check the cutting edge is facing forward.
  4. A kickback occurs when the top quadrant (or kickback zone) at the end of the cutter bar snags on a log. The resulting torque effect causes the chainsaw bar to kick upwards towards the operator. To help prevent kickback, know where the top of the cutter bar is at all times and put the bottom part of the bar into the log first. Use a safety chain and ensure that the chain brake is working. Modern chainsaws have chain brakes as a standard safety feature. More about kickbacks .
  1. Know your equipment and keep it sharp and clean. The chain can be sharpened using special files designed for each chain. The chainsaw bar can build up a burr that can be removed using a special tool. The burr will slow down the chain spinning on the bar. Carry a wedge to help free your cutter bar if it gets caught in a cut. And apply bright coloured paint to your tools so they don’t get lost or left behind in the forest.

See chainsaw maintenance video 

By providing links to external information in this summary, the Small Farms Network Capital Region is not recommending or promoting any brand of equipment. The links contain the best available diagrams and information on the topic.

The Small Farms Network Capital Region would like to thank Mr Greg Simms from BRURAL for sponsoring this field day. Sponsorship enables us to keep the cost of our workshops affordable.  Check out the range of BRURAL chainsaw equipment in store and online.

This field day was made possible with funding from the Australian Government, in-kind support from South East Local Land Services and sponsorship from BRURAL. Thank you to our sponsors ,the Palerang Local Action Network for Sustainability, and our hosts Alan and Sue for giving up their weekend to help others learn.

Tapping Into It: Water for Small Farms summary

 

Farm dams

Participants looking at erosion and farms dams on 3 March 2018

Each NSW property has a maximum volume of water (harvestable right) that can be stored in dams that is based on the area of the property. Before building a dam you need to calculate the capacity of existing dams to see if you have any more harvestable rights available (see NSW Office of Water Maximum Harvestable Right Calculator).

If you have harvestable rights available then you need to work out whether a licence is required to build a dam (see NSW Office of Water Harvestable Rights – Dams). The easiest option is to build a dam on a first or second-order stream.  Dams on third-order waterways require a licence. The order of streams is based on the pattern of blue lines for watercourses shown on topographic maps (eg look up SIX maps for your property). There is an explanation about how to work out what order watercourse you are dealing with in NSW Office of Water Dams in NSW: Where Can They be Built Without a Licence. [Your Council may also require you to lodge a development application before constructing a dam – Ed.]

Good spillway design is crucial to ensuring that excess water can be released safely when there is lots of rain. It is desirable to have good ground cover on the spillway to protect it from erosion and also to keep it dry as often as possible. A trickle pipe can be installed to release small amounts of water so the spillway is kept dry.

Farm dams can be made wildlife friendly and more attractive by excluding stock and planting riparian plants. See The Farm Dam Handbook (Water NSW) for design ideas and strategies.

What makes dams leak?

Poor construction

  • topsoil not removed before dam wall is constructed so water seeps out through topsoil layer in dam wall
  • inadequate compaction of dam wall

Poor materials

  • a waterproof dam requires 10-12% clay
  • typically dams built in basalt soils will leak

Leaking dams are expensive to repair. Options for repair include polymer material applied when dam is full or rubber or plastic liners. Contrary to popular opinion, throwing Bentonite into a dam will not fix leaks.

It is also good practice not to plant trees on dam walls to reduce the risk of their roots causing leaks when the tree dies.

Silted up dams

Aim to maintain groundcover in the dam catchment to minimise silt flowing into the dam. Silt can be cleared out of a dam by emptying the water and then bucketing out the mud and spreading it on the dam wall or elsewhere. Sometimes dams leak after this has been done because the silt has been sealing leaks.

Erosion around dams

Generally erosion is caused when a dam is built on steeper ground so that the water drops down the front edge of the dam. The eroding areas can be protected by spreading rock on them. It might also help to build a berm across the front of the dam to direct the water into a narrow channel flowing into the dam that can be protected with rock. Strategies for dealing with erosion involve slowing the water moving down the slope, covering exposed soil and re-establishing ground covers.

The NSW Government Soil Conservation Service provides consultants who can help design dams and provide advice for solving problems with existing dams.

Stock water

There are three key things to consider when planning your water supply for stock:

  • Quantity – how much is needed (see NSW DPI Primefact 326 Water Requirements for Sheep and Cattle), will you have enough in dry times? Remember that wildlife will use stock water too and you also need water for fire fighting, garden watering and to allow for evaporation (25-30% from farm dams in the Southern Tablelands).
  • Quality – different quality water is needed for different purposes (eg drinking water for humans, drinking water for stock, irrigation water for garden). You can test your water to check that it is fit for purpose. Testing is important in dry summers when salt levels can build up in dams. Blue Green Algae (which is also sometimes red/brown) is toxic and stock should be kept away from it. The NSW DPI website has more information on water quality and testing for livestock and blue green algae testing.
  • Reliability – see NSW DPI Primefact 269 Stock Water: A Limited Resource

Stock water can be provided by giving access to a dam or pumping water to troughs. Generally stock should be fenced out of dams to maintain water quality but you can fence so that they have limited access to a dam over rocky ground. Water troughs need to be kept clean and you need to make sure that all animals have access to troughs – sometimes there are bullies who keep the other stock away from the trough.

The water in the dam will be cleaner if you fence to stop stock camping in the dam catchment. It is also important to maintain 100% ground cover in the dam catchment and 80% elsewhere to reduce silt and nutrient run off into the dam.

House water

Most farms store rainwater collected from roofs in tanks for use in the house including drinking. While this tank water is relatively low risk, good hygiene is critical for ensuring water is safe for drinking. People with compromised immune systems and the elderly are most at risk.

Key actions are

  • clean house roof gutters to remove dirt and debris
  • first flush diverters can keep the dirtiest water out of the tank but they need regular maintenance to work properly
  • tanks can be cleaned (say annually) using technology similar to cleaning a swimming pool while the water is still in the tank
  • pumps should be regularly cleaned and maintained
  • drinking water can be filtered using charcoal and paper filters which should be replaced annually
  • home test kits are available to check the quality of the tank water

If the water becomes contaminated (eg dead animal in tank), water can be made safe for drinking by boiling. UV filters can also be used to clean water but are more expensive.

This field day was made possible with funding from the Australian Government, in-kind support from South East Local Land Services, the Soil Conservation Service and Veolia. Thank you to our sponsors of the network, the Palerang Local Action Network for Sustainability, and our host farm.

Small Farm Walk ‘n Talk

A group of new and prospective small farm owners gathered in November 2015 for the first field day for the Small Farms Network – Capital Region. The Small Farm Walk ‘n Talk was a friendly and information rich day held in Rossi on a small farm that has a mix of grazing land and native bush. Continue reading “Small Farm Walk ‘n Talk”