We would also like to thank: Peter Whale for his valuable participation throughout the project; Buddy Wheaton and Andrew Watson of the Office of the Land Conservation Commissioner for their comments during the project; Russell Speed, Mike Clarke, Don Bennett and Paul Findlater for their peer review comments; and Jennifer Bairstow who worked on the project at its inception. While all reasonable care has been taken in the preparation of the material in this document, the Government of Western Australia and its officers accept no responsibility for any errors or omissions it may contain, whether caused by negligence or otherwise, or for any loss , despite being caused. , supported by any person relying on it. Except for any fair arrangement for the purposes of study, research, criticism or private review as permitted under the provisions of the Copyright Act 1968, no part may be reproduced or reused for any commercial purpose without the prior written permission of Agriculture Western Australia . Authority.
Adequate preliminary site assessments were not performed in most cases, and many landowners did not know the water table level at the site of the drain before it was installed. A quarter of the landowners interviewed had received financing for their runoff and the rest were financed solely by the landowner. Many landowners report improved productivity of the land around their drains, ranging from patchy crops to good harvests.
Most of the landowners reported that they liked their drainage because it reduced waterlogging, removed water, improved farm viability, stopped the spread of salinity and/or improved production. These results are broadly consistent with research conducted in other areas of the Wheat Belt that use drainage as a tool to manage salinity.
Introduction
Study area
Method
This section attempted to capture the on-the-ground details of the drain, including how long it had been in place, how much it had cost, whether it required maintenance and the rationale for the drain location. The focus was on determining what the landowners had observed on their land since the drain was installed. Any changes in land management since the drain was installed were investigated, including maintenance of the drain over time (Section 3.4).
The aim was to find out how the drain fitted into the company's business: whether it caused problems or created new opportunities (Section 3.5). This section examined whether the landowners were satisfied with their choice to install a drain and what they thought worked and what did not work (section 3.6). As part of this, landowners were also asked if they kept rain records for their farm and how long they had kept them.
The plan was to collect this data and use it to determine if the property had experienced heavy rainfall events since their sewers were built to suggest if profile salt discharge may have occurred. Additionally, it was intended to investigate whether there had been a marked change in rainfall patterns during the time they were recorded.
Results
- Site condition and alternative treatments
- Decision making and planning process
- Technicalities of the drain and its installation
- Changes in the site and the drain
- Impacts of the drain on the operations of the farm
- Landholder satisfaction with their drain
- Additional questions
Most landowners had experienced either waterlogging or salinity in other areas of their farm. A number of landowners did not ask specific questions before proceeding with their drainage for a variety of reasons. Many of the landowners did not have a specific time frame in mind for how long they thought it would be before the drainage had the impact they expected.
Fifteen landowners placed their drains in the valley floor or right next to them. One of the drains was excavated at a break in the slope, where the type of soil changes. All of the studied drains (except buried drains) have some type of embankment or embankment.
Apart from three recently dug drains, most of the other landowners reported improvements in the soil around their drain. Most of the landowners have reported an improvement in productivity in the land surrounding the drain since installation. Two of the landowners with buried drains now sow or grow pasture up to and over the top of their drains.
Most landowners with drainage are now planting as close as possible to the edge of the drainage spoil. This varies from approximately 50 m away from the drain to the edge of the drain damage. However, some of the landowners have not seen any improvement in vegetation since the drainage was installed, rather it remains as before.
When asked about perceived changes to the water table, half of the landowners did not know the current depth of the water table. Most of the landowners have noticed that their drains now have a much reduced flow compared to when they were first installed. Half of the landowners saw no changes and three said it was too early to tell.
Many felt that extensive maintenance along the entire length of the drain was unnecessary. Most landowners believe that their runoff will continue to have a positive impact in the future.
Discussion
This very wet year in the NAR may have resulted in an acceleration of the rise in the water table, but it may have since fallen and the soil remains saline due to the lack of torrential rains in the dry seasons since 2000. The other key finding in decision-making process is the lack of proper survey of the site by many landowners prior to digging their sewers (also illustrated by the previous quote). This may increase the overall cost of the disposal, but it is better to do the job right by creating a more targeted solution to the problem and, as Yandle (2004) argues, will save expensive maintenance in the future.
A variety of reasons were given for the installation of drainage – each landowner had a different target for treatment, highlighting how individual and site-specific the salinity and clogging problems are on each property. As previously mentioned, culverts also contribute heavily to runoff costs (where landowners and not the Shires were paying) and maintaining these areas will be an ongoing cost in the future (for both landowners and the Shires). Receiving funds as part of a group may also deprive landowners of some autonomy in making decisions about runoff on their property.
Most of the impacts of drainage observed by landowners in this study are positive and seem to confirm this theory. Many have seen improved productivity in the area since the drain was installed, in some cases cutting to the edge of the drain (though reportedly patchy in most areas). This issue may be important for the perception of the success of drains on some farms.
There is anecdotal evidence in some parts of the region of similar changes taking place on landowner properties where deep drainage has not been used. During field investigations of the soil in the vicinity of the drains, especially on alluvial and floodplains, it appeared that these were mainly still moderately to extremely saline (Stuart-Street et al. in prep). Long-term hopes for the future of the land around the drain were dominated by their desire for the land to return to full productivity and for the spread of salinity to be halted.
This varies from none at all to sporadic - mainly focused on diver areas - to regular cleaning of the surface water structures near the drain. The interviews revealed that many landowners felt that sewerage had a negative impact on day-to-day farm operations, particularly in terms of access to pastures for vehicles and livestock. Chandler and Coles (2003) found that the majority of landowners they surveyed said deep drains were beneficial in some if not all situations and led to land improvements. 1999) had the same response to the general view of landowners that work is being carried away.
Conclusions
Recommendations
Appendix 1
How long did you believe it would take for the drain to have the impact you were. Was there a delay in installing the drain after you decided to go ahead with it, and if so, can you explain the reasons for the delay. If so, how was this dealt with at the planning stage before the drain was installed (eg did the Shire comment on the plan).
Can you describe what the soil around the drain looks like now that it is installed. Have you made any agronomic changes to the paddock(s) where the drain is located since installation. Since the drain was installed, have you noticed a change in the productivity of the land around the drain, and if so, can you describe the changes.
If applicable, describe how many feet or meters you are from the drain. Have you noticed changes in the soil in the affected area since the drain was installed. Do you hope to reclaim the land and bring it back into production; contain the current extent of salt-affected soil; or adapt to having salt affected soil by changing.
What do you think the area around the sewer will look like in the future? If so, at what distance from the drain do you think you saw a change. Can you describe any changes in flow you have observed since the drain was installed?
What changes in the appearance of your drain have you noticed since installing it. Do you believe that the drain (a.) has been effective; (b.) value for money; (c.) effective and value for money; or (d) too early to tell. Do you have any questions or additional comments you would like to add?
