A catchment is an area of land where water collects when it rains, often bounded by hills. As the water flows over the landscape it finds its way into streams and down into the soil, eventually feeding the river (Georges River, 2018). Every area of land on the planet is part of a catchment and they can range greatly in size from small urban catchments to massive catchments such as the Murray Darling. Catchments are very complex, if something happens in one part of the catchment it can have an impact on other parts as well. It is important that our catchments are looked after and managed as they are vital for human existence and provide our community with clean drinking water, areas for recreation, habitats for plants and animals as well as reliable and clean water for irrigation and stock.
As a consultant of the Healthy Waterways program, an investigation has been undertaken in regards to the health and sustainability of the catchments in our local area. The aim of this investigation was to test the water quality of three different rivers in the Pioneer River catchment area as well as looking at the effects of human impacts on the catchment. Two proposals have been suggested in an attempt to manage and sustain the catchments in our local area, these proposals include:
Signage placed around the catchment area with details on why the area needs to be protected and a fine of $1000 for damage/negative impact on catchment.
Employment of an officer to patrol water ways and clean up (rubbish, control weeds, report back on health of creeks, wetlands, streams, rivers).
In order to collect this data, a field trip was organised. The rivers that were visited during the trip was the Dumbleton weir, Finch Hatton river and the Marian river which are all situated in the Pioneer River catchment area. A variety of different techniques were used to test the water quality of these rivers that included testing the pH levels, salinity, turbidity etc. The data collection methods overall were relatively effective with a few limitations. One limitation is that the rivers were visited at different times of the day which will have an effect on the temperature and turbidity data results. Another limitation may be the location in the river where the testings were done. The results may vary depending on what part of the river the data is collected as the quality of water varies e.g flowing section compared to a stagnant part of the river.
2.0 STATEMENT/DISCUSSION OF FINDINGS
The Pioneer Catchment area and its current land uses:
The Pioneer Catchment area covers approximately 1,550 square kilometres of the Mackay Whitsunday Region. In Appendix 1, outlined in red shows the catchment area of the Pioneer River. The major towns that are part of the Pioneer River catchment area include Mackay, Eton, Finch Hatton, Marian and Mirani. The river begins in the Pinnacle Ranges and flows in a northerly direction into the Pioneer Valley. The river then begins to flow to the east before reaching its mouth and emptying in the Coral Sea in East-Mackay. A major part of the catchment lies inland and is divided into two sub-catchments. As seen in Appendix 2, the majority of land use in the Pioneer River catchment area is occupied by graziers, forestry and sugarcane farms. The eastern side of the catchment area is where the mouth of the river lies, this is where the majority of urban and other intensive land uses are as well as sugarcane farm use. Further inland, forestry and grazier land dominates the land use as well as sugarcane farms and nature conservation use.
Human Impacts on catchments:
Figure 3 shows the sources of nitrogen found in the Pioneer catchment area. The major contributor of nitrogen comes from sugar cane farming and the fertilisers that are applied to these crops by farmers. The fertiliser runs off the land when it rains and finds its way into rivers and streams. The chemicals negatively impact the water quality and consequently endangers plant and animal life in the catchment area. The fertilisers also make the water unfit for human consumption.
Figure 4 shows the contributors of the fine sediment that is found in the pioneer catchment area. The data reveals the main cause is stream bank erosion. The second highest contributor is sugar cane , followed by grazing and urban use. Humans contribute to erosion by clearing vegetation along river banks to plant crops and or construct housing. The soil has nothing to help keep it stable so it runs into rivers and streams when it rains and floods. The sediment negatively impacts the health of the river by changing the water flow and endangering ecosystems.
The temperature results were as expected, the Finch Hatton river testing shows the lowest temperature (see appendix 5) as the data was collected around mid morning. The highest temperature was recorded in Marian in the middle of the day and a slightly lower result in Dumbleton at around 1:30pm. The results for dissolved solids were all within an acceptable level for human consumption. Dissolved solids refer to any minerals, salts, metals, cations or anions dissolved in the water (Water Research Centre, 2014). The Finch Hatton reading was the most favourable for dissolved solids as well as turbidity. Turbidity is a measure of water’s lack of clarity. Water with high turbidity is cloudy, while water with low turbidity is clear (Vernier, n.d.). An increase in water temperature can result from poor turbidity. The link between poor turbidity and high water temperature was proven by the results at both Marian and Dumbleton Weir. The pH results for all three rivers were at acceptable levels with the Dumbleton Weir being neutral at 7.0 which is slightly below the optimum pH for river water of around 7.4. The testing of pH expresses the acidity or alkalinity of a solution on a scale of 0-14.
Salinity tests the concentration of dissolved salts in water. There were no issues with salinity across the three rivers with 0ppt readings for all. An anomaly was identified in relation to the temperature, turbidity and dissolved oxygen readings. The dissolved oxygen level was higher then expected at Marian given the high turbidity and water temperature. All readings for dissolved oxygen were above the minimum of 3ppm that is necessary to sustain the health of aquatic organisms. The nitrate levels in all three rivers were 10mg/L, this is an unhealthy level of nitrates in freshwater as the natural level is less than 1mg/L. This can have an effect on the freshwater aquatic environment which will then have an effect on the aquatic animals. A healthy level of phosphorous in a river is around 0.1mg/L, all three rivers had an unhealthy amount of phosphorus present which will also have an effect on the aquatic life. An excessive amount of nutrients in a river can encourage the growth of blue-green algae which can become toxic to the ecosystem and aquatic animals if it is excessively grown.
Overall, all three of the rivers are reasonably heathy. All measurements of overall health are within an acceptable level however, the nitrate and phosphorus levels were at an unhealthy level. The high levels are most likely due to the runoff of fertilisers that are used on crops. The clearing of vegetation for grazier use, planting crops and housing developments causes soil erosion and sediments going into rivers. The construction of weirs and dams will also have an effect as it changes the natural water flow of the river. This may be the reason why the results for turbidity and dissolved solids is a lot higher for the Dumbleton Weir and Marian in comparison to Finch Hatton.
3.0 EVALUATION OF MANAGEMENT STRATEGIES
The first proposal that was suggested was to place a sign around the catchment area with details on why the area needs to be protected as well as a $1000 fine for anyone who damages or negatively impacts the catchment. An environmental advantage of this proposal is that the threat of a fine may deter some people from damaging the catchment area. However, it may not be enough to deter all people and it would have to be consistently enforced for it to be effective or other wise people will ignore it. If mild damage has been caused, the fine money can be used to repair the damage however, the cost to repair the damage may be greater then $1000 meaning this proposal will not be as economically viable. An economic disadvantage is that not all fine payments will be enforced as there is not someone there to issue the fine and then make sure it gets paid. Majority of the community would in support of this proposal, specifically people who value the environment. However some people may not be in favour of this proposal as they may think the fine is unnecessary or too much.
The second proposal that has been recommended is to employ an officer to patrol the waterways and clean up rubbish etc. An environmental benefit of this proposal is that people are less likely to damage or negatively effect the catchment if a person is monitoring the area. This proposal is very environmental beneficial as the officer can also help clean up the area as well as finding any problems early and reporting them back. However, this proposal will not be as effective if the area is too large for one officer to look after. An economic disadvantage of this proposal is that it may be too expensive to hire people however, if there are considerable environmental benefits it will be value for money. It would be expected that the community would support this proposal if there was environmental benefits to come from it. The officer can also educate the community on the importance of looking after catchments.
After comparing the advantages and disadvantages of both proposals, the most appropriate one is the second proposal. This is because people are more likely to refrain from damaging the catchment if a person is patrolling the catchment area. A sign is an ineffective way in preventing people from negatively effecting the catchment and it costs money to issue and administer the fine. The second proposal is a lot more environmentally beneficial as the officer is able to clean the waterways as well as identifying problems early and reporting it back as soon as possible. It is also a better use of money as more advantages will come out of it compared to proposal 1. By having an officer to patrol the waterways, they are able to issue fines and make sure that they get paid where as a sign will not assure this.
A suggestion that would assist in implementing the chosen proposal would be to ensure the officer does not have too large of an area to cover and they are unable to keep up with the necessary work in order to manage and sustain the catchment. To improve the economic viability of this proposal, you could ask the community to offer their time in assisting with the clean up of rubbish etc. The officers role could also include testing the water regularly and keeping data records so they are aware of any water quality problems as early as possible to limit the extent of damage to the environment.