School of Civil, Environmental and Chemical Engineering
CIVI-1186 ENGINEERING PRACTICES 2
TUTORIAL – T7
TUTOR: PAULINO PIOTTO
2010 EWB CHALLENGE AT BENDEE DOWNS REPORT
Group 7A
Laurence Main – s3285747
Sam McGrath – s3135046
Sue Xu – s3231804
Johnson Sio – s3270603
Ben Xiao – s3182163
Celeste Ward – s3283750
Submission Date: 7/08/2010
CONTENTS PAGE
EXECUTIVE SUMMARY......................................................................................................................... 5
INTRODUCTION....................................................................................................................................... 6
ENGINEERS WITHOUT BORDERS ................................................................................................................. 6
EWB CHALLENGE ...................................................................................................................................... 6
PROJECT BRIEF ........................................................................................................................................... 7
Aim.......................................................................................................................................................... 7
Site Investigation .................................................................................................................................... 7
Cultural Background .............................................................................................................................. 8
Local weather patterns ........................................................................................................................... 8
DESIGN ALTERNATIVES .............................................................................................................................. 9
ALTERNATIVE 1 - GREY WATER TREATMENT ............................................................................................ 9
Background ............................................................................................................................................ 9
Design ..................................................................................................................................................... 9
Reasons for Refusal ................................................................................................................................ 9
ALTERNATIVE 2 - COMPOSTING TOILETS .................................................................................................. 10
Background .......................................................................................................................................... 10
Design ................................................................................................................................................... 10
Reasons for Refusal .............................................................................................................................. 10
FINAL DESIGN........................................................................................................................................... 11
Aim........................................................................................................................................................ 11
Considerations and Constraints ........................................................................................................... 11
Design Summary................................................................................................................................... 12
GUTTERING ............................................................................................................................................ 13
CALCULATIONS ........................................................................................................................................ 13
VARIETIES OF GUTTERING MATERIALS ...................................................................................................... 13
Vinyl...................................................................................................................................................... 13
Aluminium ............................................................................................................................................ 13
Galvanised Steel ................................................................................................................................... 13
Stainless Steel ....................................................................................................................................... 14
Copper .................................................................................................................................................. 14
FINAL SELECTION ..................................................................................................................................... 14
LOCATION ................................................................................................................................................. 14
SPECIFICATIONS ........................................................................................................................................ 15
ADDITIONAL MATERIALS REQUIRED ......................................................................................................... 15
TOTAL COST ............................................................................................................................................. 15
WATER STORAGE TANKS .................................................................................................................. 16
CALCULATIONS ........................................................................................................................................ 16
Rainwater Catchment ........................................................................................................................... 16
Rainwater Consumption ....................................................................................................................... 16
VARIETIES OF TANKS ................................................................................................................................ 17
Polyethylene ......................................................................................................................................... 17
Concrete ............................................................................................................................................... 17
Steel ...................................................................................................................................................... 17
Fibreglass ............................................................................................................................................. 17
FINAL SELECTION...................................................................................................................................... 18
LOCATION ................................................................................................................................................. 18
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Group 7A – 2010 EWB CHALLENGE
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SPECIFICATIONS ........................................................................................................................................ 19
Shearing shed water storage tanks ....................................................................................................... 19
Accommodation water storage tanks ................................................................................................... 19
Pressure tank ........................................................................................................................................ 20
TOTAL COST ............................................................................................................................................. 20
FILTRATION - FIRST FLUSH DIVERTER SYSTEM ...................................................................... 21
BENEFITS .................................................................................................................................................. 21
CALCULATIONS ........................................................................................................................................ 21
IMPLEMENTATION ..................................................................................................................................... 22
COSTS ....................................................................................................................................................... 22
PIPING ....................................................................................................................................................... 23
UNDERGROUND PIPING ............................................................................................................................. 23
Materials: ............................................................................................................................................. 23
Excavation: ........................................................................................................................................... 23
Costs: .................................................................................................................................................... 23
FIRST FLUSH DIVERTER PIPING: ................................................................................................................. 23
Materials: ............................................................................................................................................. 23
Costs: .................................................................................................................................................... 23
PUMP ......................................................................................................................................................... 24
ELECTRICAL PUMP.................................................................................................................................... 24
BATTERY OPERATED PUMP ...................................................................................................................... 24
FLOAT SWITCH ..................................................................................................................................... 25
ALTERNATIVE 1- MERCURY SWITCH ........................................................................................................ 25
ALTERNATIVE 2 - LEVER SWITCH ............................................................................................................. 25
FINAL SELECTION ..................................................................................................................................... 25
MAINTENANCE PLAN .......................................................................................................................... 26
GUTTERING............................................................................................................................................... 26
WATER STORAGE TANKS.......................................................................................................................... 26
FILTRATION .............................................................................................................................................. 26
PUMPS ...................................................................................................................................................... 26
IMPACT ASSESSMENT ......................................................................................................................... 28
ENVIRONMENTAL ..................................................................................................................................... 28
SOCIAL ..................................................................................................................................................... 29
CULTURAL ................................................................................................................................................ 30
Considerations...................................................................................................................................... 30
Design Specifications ........................................................................................................................... 30
ECONOMIC ................................................................................................................................................ 31
ENVIRONMENTAL EFFECTS STATEMENT ................................................................................... 33
SUMMARY ................................................................................................................................................ 33
PROPOSALS ............................................................................................................................................... 33
COMMUNITY CONSULTATION ................................................................................................................... 33
MATERIALS AND ASSOCIATED IMPACTS ................................................................................................... 34
Guttering .............................................................................................................................................. 34
Water Storage Tanks ............................................................................................................................ 34
Excavation and Piping ......................................................................................................................... 34
Pump ..................................................................................................................................................... 34
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Group 7A – 2010 EWB CHALLENGE
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Float Switch.......................................................................................................................................... 34
Summary ............................................................................................................................................... 34
IMPACT MANAGEMENT ............................................................................................................................. 35
CONCLUSION.......................................................................................................................................... 35
REFERENCES .......................................................................................................................................... 36
GENERAL .................................................................................................................................................. 36
SITE INVESTIGATION ................................................................................................................................. 36
GUTTERING............................................................................................................................................... 36
WATER STORAGE TANKS........................................................................................................................... 36
FILTRATION .............................................................................................................................................. 36
PIPING ....................................................................................................................................................... 36
PUMPING................................................................................................................................................... 36
FLOAT SWITCH ......................................................................................................................................... 36
CULTURAL ................................................................................................................................................ 36
APPENDIX ................................................................................................................................................ 37
FIGURES .................................................................................................................................................... 37
TABLES ..................................................................................................................................................... 42
APPENDICES.............................................................................................................................................. 46
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Group 7A – 2010 EWB CHALLENGE
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Executive Summary
This proposal has been designed to be environmentally sound, culturally approved, technically feasible
and economically reasonable. It falls under the original development objectives for the site outlined by
Engineers Without Borders and the Kooma Traditional Owners Association Incorporated (KTOAI). A
site analysis was conducted between 19/07/10 and 16/08/10 to highlight any areas of interest and/or
relevant site constraints. Both physical and hydrological characteristics were also considered during the
selection process. Upon having analysed the site and involved constraints in detail, many options of
development were brainstormed but brought to an appropriate number of three potential decisions which
were eventually refined to the final project proposal. On the 23/08/10, these options were presented,
along with the chosen design.
The aim, as quoted by Group 7A is “to design a sustainable rainwater catchment and storage system that
will provide sufficient water for drinking, showering and cooking for an estimated 20 people per day.”
To achieve this aim, approximately 86m of guttering would be installed along the lengths of the shearing
shed, and connected to water storage tanks via piping and a filter system. 3 water storage tanks of
4630mm in diameter would be installed along the length of the shearing shed, on the southern side. They
would have a separation of 30cm, and be connected via PVC pipes of 90mm in diameter. These pipes
would then join the tanks at the 10% water level mark, which is 34cm high. Having the three tanks
connected enables the water to be pumped from the tank closest to the accommodation, as opposed to
having piping from all three of the tanks.
The accommodation is located approximately 80m north-west of the shearing shed. The piping will then
run between the two buildings, heading north-west for approximately 100m. At the accommodation
approximately 44m of guttering will capture rainwater and direct the flow into piping, through filtration
and into the two 4100mm diameter tanks that will be located on the eastern side of the building. The
piping will connect to the tank closest to the shearing shed. Once again a connective pipe 90mm in
diameter and 30cm in length would run between the two tanks at the 10% water level mark (41cm high),
eliminating the requirement for further pipe connections. A pipe would then run to the pressure tank
which is 1m north and 5m high. The pressure tank has a capacity of 2000L and its elevated positioning
on a steel structure would put the water under sufficient pressure to pump it into the accommodation as
required. Having completed an impact assessment, the environmental, cultural, economical and social
benefits of this development are tremendously high and will be an extremely sustainable development for
the residents of Bendee Downs, and the KTOAI.
Figure 1.1 – KTOAI and EWB at Bendee Downs
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Group 7A – 2010 EWB CHALLENGE
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Introduction
The following report is a proposal to Engineers Without Borders assessing the feasibility of
implementing a conceptual design to the Bendee Downs community. The report draws on factual
information ascertained from the EWB Challenge Design Brief and various other resources to construct a
solution to problems confronting the Kooma people. All measures have been taken to ensure that every
aspect of implementation and operation of the project will satisfy social, economical, cultural and
sustainable requirements.
Engineers Without Borders
EWB Australia is a non-profit organization established in 2003 to aid in the development of
disadvantaged communities. The organization is made up of over 4,000 members comprising students
and professionals working together to educate and implement sustainable engineering projects. EWB is
working towards achieving its vision of a world where “every individual and community has adequate
access to the resources, knowledge and technology necessary to meet their self-identified human needs”.
By working with communities lacking these fundamental elements, EWB Australia is improving the
quality of life for communities in Australia and Asia Pacific.
EWB Challenge
The EWB Challenge is an initiative developed by Engineers Without Borders Australia to engage first
year university students in a real world sustainable development project in the Australasian region. A
design brief is produced each year focusing on current issues facing engineers working towards a
sustainable future. Since its commencement in 2007, the Challenge has grown to incorporate 26
universities around Australia. Previous challenges called upon students to work on projects based on
current circumstances of communities living in regions of India and Cambodia.
Figure 1.2 – Satellite Image of Bendee Downs (28° South, 146° West)
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Group 7A – 2010 EWB CHALLENGE
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Project Brief
Aim
The 2010 EWB challenge draws upon the partnership of the Kooma Traditional Owners Association
Incorporated (KTOAI) and the EWB. The focus of the 2010 challenge is to construct a proposal for
Bendee Downs that aids the progression towards building the site into a regional hub for the area. In
order to maintain the ecology of the region, the complex must be adequately designed to cater for five
permanent residents, with water, food, energy and waste production taken into consideration. As the site
grows into a centre for eco-tourism, sustainable designs must allow for up to 20 people.
Major areas of concern have been outlined by the KTOAI and EWB, and give participants the choice of
various topics to be addressed. Such options are building design, transport, water supply, sanitation,
waste management and energy. Proposals from all areas of interest will support Aboriginal Communities
in south-west Queensland and contribute to EWB’s ongoing work with the Kooma people.
Site Investigation
Bendee Downs is located at 28° South and 146° West in south-west Queensland. Consisting of two major
structures, the shearing shed and the site accommodation, the site has operated as cattle and sheep
stations for the past hundred years. However in a bid to preserve the natural surroundings, the KTOAI
have devoted one quarter of the property as a nature refuge, removing all cattle grazing in the last five
years and are hopeful of maintaining this standing. Although the removal of grazing has preserved the
natural landscape, the infrastructure has degraded to an inhospitable level with the lack of attention over
the five years.
The landscape of the Bendee Downs region is iconic of the Australian outback, with native fauna
dominating the sandy planes. The Nebine Creek is a major feature of the landscape, flowing 40 km’s
through the Kooma properties. During wet season the wetlands inject life into the bird and fauna diversity
displaying the famous Australian eco-system.
Figure 1.3 – Murra Murra and Bendee Downs Location (28° South, 146° West)
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Group 7A – 2010 EWB CHALLENGE
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Cultural Background
The Kooma Traditional Owners Association Incorporated (KTOAI) was granted the properties of Murra
Murra and Bendee Downs in 1998 by the Indigenous Land Corporation (ILC). Currently the property is
home to two families, responsible for the upkeep of the land. Occasionally other Kooma people visit the
site for matters of business, and family or cultural gatherings.
The Kooma people are alike most of Australia’s Indigenous Population, experiencing a gap in living
standards in comparison to other Australians. Cheryl Buchanan is the current Chair of the KTOAI, and
has taken it upon herself to represent her people and is an unofficial advocate for Aboriginal rights in
Australia. Cheryl and KTOAI’s vision is “to use the properties as a ‘regional hub’, a training ground
and base for the renewal of all our people and the protection and wise management of all of our
traditional lands. We wish to meet their cultural responsibilities; and further to set an example in our
country of the importance of a sustainable and continuing connection to country through inclusive
management as their ancestors did and make Kooma people proud.” The community at Bendee Downs
is actively trying to address the issues that are preventing development, with a key focus on education
and employment. By improving the site in question, KTOAI hope to encourage tourism in the local area,
generating profit, as well as providing a cultural meeting point for traditional owners of the region.
Local weather patterns
The closest climatic station is located on Mary Street in Bollon, 80.04km East of Bendee Downs. The
station’s site number is 044010 and is located 28.03 °S and 147.48 °E, at 182m elevation. It commenced
in 1885. Average temperature and rainfall statistics are as follows (Refer to Appendix A-C for graphs):
Statistics
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Years
Mean
35.5 34.3 32.0 27.8 23.0 19.5 19.0 21.4 25.6 29.6 32.8 35.0 28.0
99
maximum
temperature
(°C)
for
years 1907
to 2010
Table 1.1 – Average Maximum Temperature at Bollon (1907-2010)
Statistics
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Years
Mean
21.5 21.0 18.2 13.2 8.7
5.7 4.2 5.6
9.2 13.7 17.2 19.9 13.2
97
minimum
temperature
(°C) for years
1907 to 2010
Table 1.2 – Average Minimum Temperature at Bollon (1907-2010)
Statistics
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Years
Mean
63.1 53.4 49.9 31.6 32.7 29.9 27.8 22.3 24.5 35.3 40.8 52.2 463.4
125
rainfall
(mm)
for
years 1885
to 2010
Table 1.3 – Average Rainfall at Bollon (1885-2010)
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Group 7A – 2010 EWB CHALLENGE
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Design Alternatives
Alternative 1 - Grey Water Treatment
Background
The redevelopment of Bendee Downs into an environmentally sustainable tourism hub, would place a
great stress on the already low water sources available to the site. To consider the viability of lessening
the water consumption of the occupants and increasing the water usage efficiency seemed an obvious
matter to be assessed. Considering the expected occupancy of the site was at approximately 20 people per
day, water usage for showers, toilets and cooking would mean a high amount of grey water would be
produced. Currently there existed no systems in place to capture and re-use this water.
Design
The first alternative was a grey water filtration system (Refer to Appendix D) to produce potable water
available for consumption by the Bendee Downs occupants. The proposal involved treatment of the grey
water using two methods, a sediment tank (Refer to Appendix D) and a slow sand filtration system (Refer
to Appendix E). The sediment tank was the major storage site and the first point of filtration for the grey
water. It involves a mechanical arm to turn the water to keep it from becoming stagnant and producing
pathogens. The major treatment system at this stage however is the addition of a chemical known as
Alum. In a sediment tank, Alum is added to the water so that the negatively charged pathogens stick
together and become heavy when the alum neutralizes the particles. The heavy unwanted particles sink to
the bottom of the tank and therefore become easy to separate, being released in the form of sludge.
Once the heavy sludge has been removed, the effluent is transported to the slow sand filter for further
purification. Slow sand filters work via the formation of a layer known as a biofilm, which forms on the
top few millimetres of the fine sand layer. The layer consists of bacteria, fungi, and a range of aquatic
insect larvae formed in the first 10 to 20 days of operation. As water passes through the biofilm miniscule
particles are caught in the layer, with dissolved organic material being eaten by the bacteria. The biofilm
is the layer that provides the purification, with the underlying sand providing a stable base for the
treatment layer. Water produced from a properly operating sand filter can reduce bacteria from up to
99%.
After having passed through both the sedimentary tank and the slow sand filter, the previously discharged
grey water is now piped back into the accommodation, suitable for drinking, cooking, cleaning and
showering.
Reasons for Refusal
When considering the proposed alternatives, the viability of each option was weighted on its
sustainability, cultural impacts, cost, and maintenance requirements (Refer to Appendix F). The grey
water treatment system offered a practical solution to the water supply concerns confronting the Kooma
people, but when broken down to the above-mentioned categories, proved less viable than the other two
alternatives.
Sustainability and maintenance were the treatment systems major downfalls. As it is quite a technically
intricate system, with mechanical operations creating areas of possible complications come
implementation. The maintenance also rated poorly against other alternatives, with regular cleaning of
the sand filter likely to be an unwanted hassle to the Kooma people (Refer to Appendix F).
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Group 7A – 2010 EWB CHALLENGE
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Alternative 2 - Composting Toilets
Background
In 2003 Bendee Downs received its first sewage system, capable of handling waste from about twenty to
thirty people a week. Currently waste is transported to two buried polyurethane septic tanks, where it is
turned, before the liquefied effluent is sprayed across a grass paddock and sterilized by the sun and
bacteria. Some problems have arisen with the effluent gathering in a natural basin close to the housing
area, degrading the wetland, causing unpleasant odours and possible disease threats. Alternative 2 was
formed in response to the need for a more suitable waste treatment system that could cater for higher
numbers of visitors.
Design
The proposal for a composting toilet system (Refer to Appendix G) at Bendee Downs was heavily
favoured for its innovative concept, and its elimination of water usage. The design involved installing
toilet blocks where aerobic decomposition of human waste was allowed to occur at the point of excretion.
The decomposition occurs by creating optimum temperatures in which bacteria thrive, and therefore are
able to break down the waste, consuming harmful pathogens, and reducing volume. The system would
also require a drainage system for excess liquid to avoid extreme moisture levels.
Below the toilets was a removable container, which required rotation every six months, where the
decomposed waste is then transferred to a compost heap. The only power operated component of the
composting toilets is a small fan below the toilet block, to aid in the removal of odours. The fan was
likely to have been powered electrically by the site generator or from solar power. One composting toilet
is capable of handling the daily requirements of eight adults comfortably. Considering this, and the
expected 20 visitors to Bendee Downs, the project would have involved installation of two toilet systems
in the toilet block, one female and one male.
Reasons for Refusal
The proposal for a new sanitation system at Bendee Downs seemed an ideal solution to the waste
treatment issues currently impacting the Kooma people. Its sustainability scored highly in the design
matrix, with its life span expected to continue over a few decades with little impact on the ecology of the
area. It was however the cost and maintenance of the system that prevented it from ultimate selection.
To install the composting toilets at Bendee Downs would have required construction, either as an
extension of the accommodation or as an entirely new structure. Our aim for the Kooma people was to
create a regional tourist hub that did not detract from the iconic Australian outback that surrounds the
area. Excessive construction may have interfered with the scenery that Bendee Downs was offering to
visitors. It was also suggested that the requirement of physical removal of the waste, although only
needed twice a year, would become an unwanted responsibility.
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Group 7A – 2010 EWB CHALLENGE
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Final Design
Aim
“To design a sustainable rainwater catchment and storage system that will provide sufficient water for
drinking, showering and cooking for an estimated 20 people per day.” – Group 7A
Benefits of implementing a rainwater catchment and storage system at Bendee Downs:
•
•
•
•
•
•
using the heavy rainfall during the wet season to our advantage (Refer to Appendix C)
utilising the large surface areas of the shearing shed and accommodation (Refer to Figure 1.4)
eliminating the reliance on ground water for drinking purposes
lessening the impacts caused by groundwater overuse, such as the cone of depression, land
contamination due to high concentration of salts, and shifting of the water table
accommodating the predicted increase in visitors and people living on site
respecting the indigenous communities wish to leave the groundwater as a sacred water source
(Refer to Appendix H)
Considerations and Constraints
Water available at Bendee Downs:
Groundwater
• Drinking water is extracted from the main bore at Bendee Downs, which accesses the Hurray
Sandstone Formation
-has good pressure
-clean water
• Other bores in the area access the Wyandra Formation
-used mainly for agriculture
-not suitable for human consumption
Surface water
• Nebine Creek
-only flows following rain in the upper catchment
-dry for most of the year
• Extensive system of lakes
-generally less than 1.5m in depth
-dry for most of the year
Issues with current Water Supply System
•
•
•
•
•
11
the great extractions from bores are lowering the pressure and are unsustainable
been in use for over a century
the dreamtime of region refers to an Indigenous community known as the “hairless ones,” they
were known to drink the bore water and therefore it is known as sacred
ground water from the Wyandra Formation is saltier than surface water and contain minerals
which could potentially degraded the land to the point of which nothing will grow
a more sustainable water source is required to provide for the increased number of people visiting
the site
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Design Summary
The two selected catchment areas for rainwater harvesting on Bendee Downs are the accommodation and
shearing shed. They are the two main buildings on site, and can capture a total of 202, 000L per annum,
which will easily provide water for drinking, showering and cooking for the estimated 20 people per day.
Approximately 86m of guttering will be installed along the lengths of the shearing shed, and connect to
water storage tanks through piping and a filter system. 3 water storage tanks of 4630mm in diameter will
be installed along the length of the shearing shed, on the southern side. They will have a separation of
30cm, and will be connected via PVC pipes of 90mm in diameter. These pipes will join the tanks at the
10% water level mark, which is 34cm high. Having the three tanks connected will enable the water to be
pumped from the tank closest to the accommodation, as opposed to having piping from all three of the
tanks.
The accommodation is located approximately 80m north-west of the shearing shed. The piping will then
run between the two buildings, heading north-west for approximately 100m. At the accommodation
approximately 44m of guttering will capture rainwater and direct the flow into piping, through filtration
and into the two 4100mm diameter tanks that will be located on the eastern side of the building. This will
protect the tanks from direct sunlight during the hottest period of the day. The piping will connect to the
tank closest to the shearing shed. Once again a connective pipe 90mm in diameter and 30cm in length
will run between the two tanks at the 10% water level mark (41cm high), eliminating the requirement for
further pipe connections.
A pipe will then run to the pressure tank which is 1m north and 5m high. The pressure tank has a capacity
of 2000L and its elevated positioning on a steel structure puts the water under sufficient pressure to pump
it into the accommodation as required.
Figure 1.4 – Aerial view of proposed water supply design (for scaled design refer to Appendix I)
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Group 7A – 2010 EWB CHALLENGE
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Guttering
Calculations
Dimensions of rainwater catchment area (Refer to Appendix I):
• Shearing shed = 40m x 10m
• Undercover area = 6m x 7m
• Accommodation = 22m x 12m
Length of guttering required (Refer to Appendix I):
• Shearing shed (plus undercover area) = (40 x 2) + 6 = 86m
• Accommodation = 22 x 2 = 44m
Total length of guttering = 86 + 44
= 130m
Varieties of guttering materials
There are a variety of materials to choose from in the guttering industry. The materials considered for
implementation at Bendee Downs are as follows:
Vinyl
Vinyl gutters are renowned for their ease of installation, because they are so lightweight and sections
simply snap together. Vinyl gutters are the cheapest guttering material to purchase, and never rust or
corrode. When used in temperate climates they function equally as well as other materials, especially
when installed correctly. Vinyl gutters do however grow brittle and crack in extreme weather conditions,
giving them a relatively short lifespan, with no guaranteed warranty.
Aluminium
Aluminium gutters are also relatively lightweight, rust-proof and simple to install, though unlike vinyl
they are extremely weather-resistant. They are the most popular gutter material available as they are long
wearing and are backed by a 25-30 year manufacturer’s warranty. Aluminium gutters aren’t structurally
as strong as other gutter materials, but if installed carefully, this should not be an issue. These gutters can
be purchased in the specific lengths required, as opposed to short lengths that require joining; this is
known as seamless guttering. By eliminating joiners in the guttering, any chance of leakage or failure is
also eliminated. Aluminium gutters are also very economical, at approximately $5/m.
Galvanised Steel
Galvanised steel gutters are competitive cost-wise and more durable than their aluminium counterparts
when it comes to damage resulting from falling branches. Galvanised steel gutters will eventually fall
victim to corrosion. This process can begin as soon as 5 years post-installation, in paint-chipped regions
of the guttering. However, they can last for up to 15 years if correct maintenance procedures are adhered
to.
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Group 7A – 2010 EWB CHALLENGE
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Stainless Steel
These gutters are nigh on indestructible. Stainless steel gutters don’t require paint, are rust-proof and are
accepted to be the strongest material in the industry. The main drawback is cost, as they are
approximately 4 to 6 times more expensive than guttering made of lesser materials.
Copper
Copper gutters are the most aesthetically pleasing gutters on the market, and like stainless steel are
virtually indestructible. However, they are the most expensive gutters available at approximately $30/m.
Final Selection
After careful analysis of the wide range of guttering materials available on the market, aluminium
guttering was chosen for implementation at Bendee Downs. This variety of guttering proved to be the
most viable economically, aesthetically, physically and sustainably. Vinyl guttering was immediately
discounted due to its low weather-resistance in extreme climates, such as at Bendee Downs. Copper and
stainless steel guttering was also not plausible due to the extremely high cost of materials.
Aluminium was chosen over galvanised steel guttering as it requires less maintenance, has a 25-30 year
manufacturer’s warranty and is rust-proof. Galvanised steel is stronger than aluminium, but as discovered
during the site analysis, there are no trees located near the accommodation or shearing shed, and
therefore no potential hazards to the aluminium guttering structures (Refer to Appendix J).
Location
The guttering will be installed at both the shearing shed and accommodation. As both of the buildings
roofs are pitched, and are constructed with corrugated iron, the water will flow down the roofing towards
the northern and southern sides. This means that guttering will only be required along the lengths of the
buildings, as opposed to the entire perimeter.
Figure 1.5 - Aerial view of guttering at Accommodation (for scaled design refer to Appendix K)
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Group 7A – 2010 EWB CHALLENGE
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Figure 1.6 - Aerial view of guttering at Shearing Shed (for scaled design refer to Appendix L)
Specifications
•
•
•
•
•
Length – approximately 160m
Dimensions – 1500mm x 2000mm (to cope with the high volumes received)
Warranty – 30 years
Cost per meter - $5
Source – Furmor Plumbing, Dalby
Additional materials required
•
•
•
•
•
•
•
Downspout – gutter attachment that brings the water down the side of the building, the water
capacity of the guttering system is dependent on the size of the downspout.
Elbow – attached to the downspout and sets its direction to a 45 degree angle.
Mitre – changes direction of the gutter flow.
End cap – used for ends of gutter runs.
Spire and Ferrule – ensures width of gutter is consistent throughout the run.
Strap – used to attach the downspout to the building.
Splash Block – if the gradient of the soil around the foundation of the house is pitched, a splash
block may be used to divert water from the foundation.
Total Cost
= length (m) x cost/m
= 130 x 5
≈ $650 (+ additional materials required)
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Group 7A – 2010 EWB CHALLENGE
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Water Storage Tanks
Calculations
Rainwater Catchment
Roof area available for capture = shearing shed + undercover area + accommodation
•
•
•
∴
Shearing shed = 41 x 9.5 = 389.5m² ≈ 390m²
Undercover area = 6.5 x 15.5 = 100.75m² ≈ 100m²
Accommodation = 20.5 x 11 = 225.5m² ≈ 226m²
Total roof area available for capture = 390 + 100 + 226 ≈ 706m²
Amount of rain water that can be captured per year = roof area x average annual rainfall
•
•
•
•
∴
Average annual rainfall = 376 mm/year
Loss of capture to evaporation and first flush ≈ 25%
Shearing shed + undercover area = 490 x 376 = 184, 240L = 184mᵌ x 0.75 ≈ 138mᵌ
Accommodation = 226 x 376 = 84, 976L = 85mᵌ x 0.75 ≈ 64mᵌ
Total amount of rain water that can be captured = 138 + 64 ≈ 202mᵌ
Rainwater Consumption
Daily consumption of rain water = number of people per day x number of litres
•
•
•
∴
Drinking water = 20 x 3 = 60L/day
Cooking water = 20 x 3 = 60L/day
Shower water (9L/min, 3 min) = 3 x 20 = 60min = 60 x 9 = 540L/day
Total daily consumption of rain water = 60 + 60 +540 = 660L/day
Water needed over dry period = daily consumption x longest period without rain x days/ month
•
•
•
•
∴
Longest period without rain = 8 months
Drinking water = 60L x 8 months x 30.5 days per month = 14,640L = 15mᵌ
Cooking water = 60 x 8 x 30.5 = 14, 640L = 15mᵌ
Shower water = 540 x 8 x 30.5 = 131760 L = 132mᵌ
Total amount of water needed over dry period = drinking water + cooking water + shower
= 15 +15 +132
≈ 162 mᵌ
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Group 7A – 2010 EWB CHALLENGE
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Varieties of tanks
There are a range of different tanks available on the market. Some of which include:
•
•
•
•
Polyethylene
Concrete
Steel
Fibreglass
Polyethylene
Polyethylene is a UV stabilised, food grade plastic. These tanks are light and only require a sand base to
be placed on. They come in a wide variety of colours and have a lifespan of approximately 30 years. Poly
tanks (Refer to Appendix M) are one of the cheapest options available and can withstand extreme
temperatures. They are comprised of petrochemicals and aren’t biodegradable. However, polyethylene
tanks can still be easily recycled.
Concrete
Concrete water tanks can be installed either above or below ground. They are very heavy and are often
poured on site, or transported in segments and then cemented together. Concrete tanks require a liner
such as a polyethylene layer. Without it, the tank will leach lime and over time the water will turn slightly
alkaline. Also as concrete is slightly porous, water will penetrate into the concrete over time which may
cause corrosion problems in relation to steel framework. Concrete requires a great deal of heat and water
in its production.
Steel
There are 3 main types of steel tanks; galvanised steel, Zincalume and Colorbond.
Galvanised tanks are the cheapest type on the market as they only last for up to 5 years. The steel is
galvanised with zinc, which assists in slowing the corrosion process. However galvanising the steel is not
enough to stop the electrolysis that takes hold on the steel.
Zincalume has been available for the past 30 years and was originally used for roofing. It’s comprised of
a mix of 55% aluminium, 43.5% zinc and 1.5% silicon bonded to steel. These tanks are usable for about
10-15 years.
Colorbond is Zincalume with a conversion layer applied to the surface of the steel to improve adhesion. It
also has a polyester primer baked on, followed by a top coat of paint that is also baked on. These tanks
can have up to a 20 year warranty, but a scratch in the surface will greatly speed up corrosion rates.
Fibreglass
Fibreglass tanks are relatively expensive and long-lasting (up to 20 years). They are light-weight, yet
strong and resistant to corrosion. Fibreglass tanks can be installed above or below ground. These tanks
tend to let more light in, promoting algae growth and should therefore be painted. Although fibreglass is
a strong material, it tends to be brittle, leaving it prone to cracks. Fibreglass doesn’t react to extreme
temperatures as well as other tank materials.
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Group 7A – 2010 EWB CHALLENGE
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Final selection
Water storage tanks come in various shapes, sizes, colours and materials. When choosing which tank
type would be most appropriate for the design, the following was considered:
• Sustainability
• Cost
• Aesthetics
• Cultural acceptance
Based on these variables, polyethylene proved to be the most viable tank for use at the Bendee Downs
site. Not only is it the most cost effective option relative to its lifespan, but it is UV resistant and can
withstand the extreme hot and cold temperatures of the Australian desert. In addition, polyethylene tanks
don’t corrode or require a concrete foundation, which the Kooma Nation people should approve of. As
these tanks are made of light-weight material, they can be transported to the site, as opposed to bringing
in concrete-mixers and labourers to assemble the tanks. Also the light-weight factor will enable a
polyethylene tank to be used for the pressure tank, as it needs to be elevated approximately 3m. Finally, a
colour that blends with the buildings can be selected as polyethylene tanks come in a variety of colours.
Another solution to improving the aesthetics of the large tanks would be to plant native flora and create a
screen.
Location
The accommodation is located approximately 80m north-west of the shearing shed. 3 water storage tanks
of 4630mm in diameter will be installed along the length of the shearing shed, on the southern side. They
will have a separation of 30cm, and will be connected via PVC pipes of 90mm in diameter. These pipes
will join the tanks at the 10% water level mark, which is 34cm high. Having the three tanks connected
will enable the water to be pumped from the tank closest to the accommodation, as opposed to having
piping from all three of the tanks. The piping will run between the two buildings, heading north-west for
approximately 100m. At the accommodation the two 4100mm diameter tanks will be located on the
eastern side of the building. This will protect the tanks from direct sunlight during the hottest period of
the day. The piping will connect to the tank closest to the shearing shed. Once again a connective pipe
90mm in diameter and 30cm in length will run between the two tanks at the 10% water level mark (41cm
high), eliminating the requirement for further pipe connections. A pipe will then run to the pressure tank
which is 1m north and 5m high. (Refer to Appendices I, K and L)
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Group 7A – 2010 EWB CHALLENGE
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Specifications
Shearing shed water storage tanks
•
•
•
Free delivery from Dalby Rainwater Tanks Direct Depot (less than 600km away)
Includes mesh strainer and overflow outlet
25 year warranty
SHEARING SHED TANKS
Number of tanks
required
Capacity
3
Diameter
4630mm
Inlet height
3170mm
Total height
3400mm
Unit cost
$6930
46, 817L
Table 1.4 – Specification of polyethylene tanks to be installed at shearing shed (Refer to Appendix N)
Accommodation water storage tanks
•
•
•
Free delivery from Dalby Rainwater Tanks Direct Depot (less than 600km away)
Includes mesh strainer and overflow outlet
25 year warranty
ACCOMMODATION TANKS
Number of tanks required
2
Capacity
31, 822L
Diameter
4100mm
Inlet height
2540mm
Total height
2730mm
Unit cost
$4310
Table 1.5 – Specifications of polyethylene tanks to be installed at accommodation
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Group 7A – 2010 EWB CHALLENGE
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Pressure tank
•
•
•
Free delivery from Dalby Rainwater Tanks Direct Depot (less than 600km away)
Includes mesh strainer and overflow outlet
15 year warranty
PRESSURE TANK
Number of tanks required
1
Capacity
2, 000L
Diameter
1300mm
Total height
2000mm
Unit cost
$650
Table 1.6 – Specifications of polyethylene pressure tank to be installed at accommodation
Total Cost
(3 x 46, 817L tank) + (2 x 31, 822L tank) + (1 x 2000L tank)
(3 x $6930) + (2 x $4310) + ($650) = $30, 060
Figure 1.7 - AutoCAD design of tanks at accommodation (for scaled design refer to Appendix O)
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Group 7A – 2010 EWB CHALLENGE
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Filtration - First Flush Diverter System
Benefits
First Flush Diverters are a crucial part of rainwater harvesting systems. By preventing the initial
rainwater collected from the roof entering the storage tanks they:
•
•
•
•
Prevent dust and dirt, leaves, bird droppings, insects, spiders, mosquitoes and debris from
entering the rainwater tank.
Improve water quality and safety, raising the standard to comply with AS/NZS 4020:2005
(Testing of products for use as drinking water in Australia and New Zealand, refer to Appendix P)
Assist in extending the life of the pumps by preventing sediments penetrating the pump
components and wearing down the seal that separates the water from the electric motor or
batteries.
Reduce tank maintenance by diverting polluted water before it enters the water storage tank.
Calculations
Roof Area (m²) x Pollution Factor (L/ m²) = Litres to be diverted
Shearing Shed:
•
•
Pollution factor = 0.8L per m² (refer to Appendix Q)
Area = 490m²
490 x 0.8 = 392L
392÷ 3 ≈ 130L
Accommodation:
•
•
Pollution factor = 0.8L per m²
Area = 226m²
226 x 0.8 = 180.8L
180.8 ÷ 2 ≈ 90L
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Group 7A – 2010 EWB CHALLENGE
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Implementation
A First Flush Diverter system was chosen for implementation at Bendee Downs as it is an essential
component in rainwater harvesting and will effectively filter the rainwater captured to Australian
Drinking Standards. It is cost effective, and easily fitted, therefore not incurring any installation fees.
There are no mechanical parts involved in the system, and is therefore a non-invasive, sustainable
alternative. They operate best when used in conjunction with a leaf screen. First Flush Diverters are
available in a wide range of styles and sizes. Due to the large catchment areas, multiple diverters will be
required at Bendee Downs. Two 90L capacity diverters will be installed at the accommodation, one for
each tank. Three 130L capacity diverters will be fitted at the shearing shed, once again, one per tank.
First Flush systems of this size are known as stand/mounted water diverters (Refer to Appendix R). These
diverters will include 90mm PVC connection pipes, the diverter chamber and the galvanized steel stand.
The diverter chamber empties through a slow release valve and can be connected to standard irrigation
systems or directed in a northerly direction to recharge the wetlands and groundwater systems of Bendee
Downs.
Costs
The 5 First Flush Diverters are to be sourced from Dalby Rainwater Tanks Direct Depot, the same
company that the rainwater tanks are to be purchased through. This will incur free delivery and a 15%
discount on the diverters.
Approximately $60 per unit x 5 diverters ≈ $300
Figures 1.8 – Diverter System Selected for Implementation at Bendee Downs
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Group 7A – 2010 EWB CHALLENGE
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Piping
Underground Piping
PVC piping was used to transport water from the tanks located at the shearing shed to the tanks beside
the accommodation (Refer to Appendix I). Piping was installed to transport water from the
accommodation tanks to the pressure tank and then back to the accommodation for usage (Refer to
Appendix O) Piping was also installed to connect the tanks together. This pipe is fixed at 10% capacity of
the tanks and ensures the water level rises at the same rate for all tanks.
Materials:
• 30mm diameter
• PVC (polyvinyl chloride)
A 30mm PVC pipe will be used because it is sufficient to allow a flow rate of 17L/min from the shearing
shed to the accommodation tanks and a flow rate of 4L/min from accommodation to the pressure tank.
PVC is the chosen material because it is cheap, durable and easy to assemble.
Excavation:
The pipe connecting the shearing shed tanks and accommodation tank will be positioned 30cm beneath
ground (Refer to Appendix S). This means the pipe will not be exposed to the extreme climate
conditions, reducing the risk of overheating or damage. Piping above ground also runs the risk as a
hazard to visitors.
•
0.3m x 100m = 30m² to be excavated
Costs:
Length of pipe required = 120m
30 mm PVC piping: $2.50/m
Cost = 120 x 2.50 = $300
First flush diverter piping:
Because of the amount of water received in heavy rainfall the piping connecting the first flush diverter to
the tanks will need to be a bigger diameter than the pipes used to transport the water.
Materials:
• 90mm diameter
• PVC (polyvinyl chloride)
Costs:
Length of pipe required = 3.3m
90mm PVC piping = $4.50/m
Cost = $14.85
Total Cost of Piping = $315
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Group 7A – 2010 EWB CHALLENGE
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Pump
For the water to be transported from the shearing shed tanks to the accommodation tank an electrical
pump was installed. A battery operated pump was installed to transport water from the accommodation
tanks up to the pressure tank.
Electrical Pump
(Shearing shed tanks
accommodation tanks)
This electrical pump will be powered by the generator which is on site. Because the pump will only be
activated by a sensor inside the tank once water levels drop to 20% this will save power and electrical
costs.
Specifications:
Power: 240V
Capacity max: 17L/min
Pressure: 40psi
Inlet and Outlet (mm): 30 x 30
Cost: 1 x 240V electrical pump= $150.00
Location:
The electrical pump will be placed beside the shearing shed tanks.
Battery Operated Pump
(Accommodation tanks
pressure tank)
A battery operated pump will be used to pump water from accommodation tanks to the pressure tank.
This was chosen as opposed to installing a second electrical pump to reduce the reliance on the generator.
The pressure tank holds a small 2000L, and if it were to become empty during the evening, when the
generator is switched off, the residents wouldn’t be able to access water. By implementing a battery
operated pump, Bendee Downs occupants will have continual access to rainwater.
The battery operated pump will pump water at 4L/min whereas the electrical pump will pump water at
17L/min. The reason why a much larger flow rate will be needed to pump between the shearing shed
tanks to the accommodation tanks is because of the volume of water being transported. Only 400L will
be pumped into the pressure tank once water levels drop to 80% in 1 and a half hours. Whereas 12729L
will be pumped from the shearing shed tanks to the accommodation tanks once the water levels drop to
80% in 12 and half hours.
Specifications:
Power: Requires 2 x D batteries
Capacity max: 4L/min
Cost:
1 x battery operated pump= $19.95
Location:
The battery operated pump will be placed beside the pressure tank.
Total cost of pumps: $169.95
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Group 7A – 2010 EWB CHALLENGE
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Float Switch
Throughout the design phase of the project, a level of care was taken to ensure the system would operate
with minimal physical requirements from the residents at Bendee Downs. Research into similar systems
around the globe, lead to the inclusion of a float switch in the pressure tank which allows water levels to
be automatically refilled when occupants utilize the water supply. The float switch is a buoyant teardrop
shaped bulb attached to the side of the tank, which measures water level and activates the pump when a
certain amount of water has been depleted (Refer to Appendix T). Two types of float switch were
available for the project, a Mercury Switch, and a Lever Switch.
Alternative 1- Mercury Switch
The first of the two alternatives is the mercury switch, a design widely used for automatic tank re-filling
since early pumping systems existed. The simple design makes it an effective method with minimal
opportunities for complications. Inside of the buoyant float is a set of electrical contacts with electric
current flowing yet because they are not connected, are part of an incomplete circuit. The bulb also
houses a drop of mercury, which rolls back and forth as the float tilts from full capacity to depleted
capacity. When the tank volume falls to 80%, the mercury in the float gathers in the tip of the bulb,
encasing the electrodes and thus completing the circuit, and activating the pump.
Alternative 2 - Lever Switch
The other option available for the project was the Lever Switch, a relatively newer design gaining
recognition and usage in the industry. The basic design of the float is still a teardrop shape yet with a
steel ball sitting on a platform, which is free to roll back and forth in relation to the tilt of the float. At the
tip of the float is a lever controlling the conduction of electricity to the pump. The lever naturally sits in
the OFF position. (Refer to Appendix T). Depletion of water levels in the tank causes the ball to fall on
the lever, turning on the switch, activating the pump.
Final Selection
For ultimate selection the Lever Switch proved a more reliable and safer option for use in the project. The
exclusion of mercury in the float means there is no chance for contamination in the water tank, should a
leak occur in the float. The teardrop shape of the float makes it ideal for potable water tanks, as the float
has no shoulders or edges for solids to build on. The Lever Switch also proved far easier to source, with a
supplier in Brisbane able to post the package for an extra $50.
Price:
$220 each
Freight:
Model:
$50
Kelco Pty Ltd.
Brisbane
K Series
Warranty:
12 Months
Source:
Table 1.7 – Specifications of chosen lever switch
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Group 7A – 2010 EWB CHALLENGE
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Maintenance Plan
To be considered a suitable design proposal for implementation at Bendee Downs, the project in question
is required to be easily maintained by the 5 permanent residents on site. This rainwater catchment and
storage system scored the highest of all water supply options, in relation to maintenance, rated in the
proposal matrix (Refer to Appendix F). Below is a maintenance guide on each of the components that
make up the water supply system design.
Guttering
It is extremely important to maintain gutters on a regular basis. Without frequent cleaning:
•
•
•
•
•
•
Gutters can become a fire hazard during bushfire season
Water may penetrate the roof cavity and cause structural damage
Risk of corrosion increases
Insects and vermin may breed in the leaf matter and stagnant water collected in gutters, creating
serious health risks
Tank water contamination is more likely
Increases life span of tanks, pumps and piping
Maintenance of guttering is simple and can be easily undertaken by two people. One person on a ladder
(that needs to be against the wall, or self-supporting, not leaning on the guttering as it may cause
structural damage) equipped with a plastic scoop and a 3L bucket, attached to a rope. The second person
spots at the bottom of the ladder and collects the debris that the person on the ladder scoops from the
guttering and then passes down in the bucket. The guttering needs to be checked every 2 months, but
considering the location of Bendee Downs, should only required cleaning approximately every 6 months.
Water Storage Tanks
Polyethylene tanks required minimal maintenance, removal of leaves and debris from the roof, guttering,
inlet and overflow outlets once a month is all that is required.
Filtration
First Flush Diverters require very little maintenance. Periodically unscrewing the End Cap of the water
diverter to allow debris to fall out, and ensuring the outlet of the diverter is clear of any leaves will
prevent blockage and allow the diverter to be fully functional. Hose the filter screen when required and
clean the Flow Control Valve and the diverter will continue to filter the rainwater effectively.
Pumps
As long as the pumps are selected and installed correctly, maintenance issues will be minimal. The
following factors should be observed on a monthly basis:
•
•
•
•
•
•
•
26
Heat – in bearings and glands
Pressure – pump discharge pressure
Noise – cavitation, bearings
Flow – a drop off in flow
Leakage – glands – piping oil or grease
Power consumption
Vibration – an increase could indicate problems
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Every 3 to 4 months the following procedures should be adhered to, for maximum function:
•
•
•
•
•
•
•
•
Record all meter readings
Check all valves, glands and supports
Test run unit, check for correct running, noise, heat, vibration
Adjust gland if required
Check oil levels if applicable
Clean inside and outside of station (with water, ensure pump is disconnected from power)
Check condition of electrical components for hot spots
Replace 2 x D batteries when required in battery operated pump
A step-by-step procedure will be explained upon installation of the pumps, as well as written instructions
on maintenance and contact details if problems arise.
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Group 7A – 2010 EWB CHALLENGE
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Impact Assessment
Environmental
The current water supply system in Bendee Downs has been used for over a century by extracting
groundwater from the main bore accessing the Hurray Sandstone Formation. As a result, the bore
pressure is lowering, forming a cone of depression and threatening to shift the water table. Considering
the predicted increase in tourists visiting the site, the current water supply system is unsustainable and
due for an upgrade.
Installing a rainwater catchment and storage system will reduce the reliance on groundwater and provide
a sustainable water source for drinking, cooking and showering. 376mm of rainfall is received annually,
which will easily provide for the approximate 20 people per day residing at Bendee Downs. In fact,
approximately 40,000 L of excess rainwater will be stored which could be used for irrigational purposes
to lessen the degrading impact that the saline groundwater from the Wyandra Formation is having on
their local area.
The required excavation will have minimal impact as the pipe will run underground for approximately
100m and be 30cm deep. Careful analysis of the site has proven that there is no flora or fauna to be
relocated in the region between the shearing shed and accommodation, where the excavation would
occur.
The pressure tank lessens the reliance on the generator as its elevated position creates enough pressure
due to gravity to connect the water to the kitchen and showers. This will greatly decrease the amount of
electricity that would otherwise have been required to pump the water into the accommodation. In
addition, the carbon-dioxide levels, along with other pollutants will be dramatically reduced by sourcing
many of our materials locally, rather than interstate or overseas.
Pros of rainwater catchment and storage
Cons of rainwater catchment and storage
Decreases reliance on the unsustainable Aesthetics of multiple, large tanks.
groundwater source.
Excess water stored can be used for PVC pipes, non-biodegradable.
irrigation, lessening the degrading impact
that the mineral-rich groundwater from the
Wyandra Formation is causing.
Promotes sustainability and environmental Polyethylene tanks, non-biodegradable.
awareness in the community.
By sourcing tanks and other materials Excavation for piping.
locally, greenhouse gas emissions will be
greatly reduced.
Site analysis has confirmed that the Aluminium for guttering.
excavation required will not impact any
habitats, flora or fauna.
While polyethylene tanks are non- Transport of materials to the remote location of
biodegradable, they are recyclable.
Bendee Downs.
Secondary aluminium guttering can be
purchased which is comprised of recycled
aluminium.
Table 1.8 – Environmental Pros and Cons of Rainwater Catchment and Storage at Bendee Downs
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Group 7A – 2010 EWB CHALLENGE
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Social
The life expectancy of local indigenous communities has been long known to be 17 years shorter than
non-aboriginal communities on average. In order to close this gap, the government has a series of policy
that helps aboriginal people live longer and healthier. Almost 32% of death in the aboriginal folk is
caused by waterborne infection. Inadequate, high quality water supply is to blame for the high infection
rate.
It has been expected that the water tanks will not only satisfy the needs of the accommodation, but also
benefit the wetlands. The water harvested from the wet season can be channeled to vegetation for
irrigation purpose. The operation will also help cut down the high demand on ground water.
The project itself has very little negative impact on the day to day life of local community. Due to the
nature of the project, it operates in a non-invasive manner. The initial installation can be done in less than
2 weeks. The deontological approach ensures that moral obligation outweighs economic gain.
All information of this project will be posted on the blackboard in the community center where all
questions that are related to the project will be answered. Local representatives will be invited to
participate in the design and implementation of the project. Their insights and opinions will also
contribute heavily to the final decision making. The local community will be well informed during every
step of the process. No criticism and negative feeling from the local community will be taken lightly.
Weekend meetings can be arranged to resolve the problems and work out ways to minimize the negative
impact. Furthermore, locals can volunteer or to be a labourer during the construction work, which also
gives them a sense of ownership.
The education program will be launched after the installation to teach people the basic techniques of
saving and recycling water in the dry land. It will substantially change people’s view about the water and
how to protect this valuable resource.
The trust and friendship gained from the success of this project will make carrying out similar projects in
the future smoother, since the local communities will recognize the benefits of technologies. The
experience of dealing with aboriginals will also substantially change the existing approach.
Figure 1.9 – Painting by artist John Weeronga Bartoo, descendant from the Kooma tribe (Refer to
Appendix U)
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Group 7A – 2010 EWB CHALLENGE
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Cultural
Considerations
The Kooma Nation is a community of indigenous Aboriginals with a strong sense of pride and cultural
heritage, which they strive to uphold and share with other communities. Like most indigenous
communities, their history dates back long before European settlement. Considering this, it is not
surprising they maintain beliefs of the dreamtime period handed down by their ancestors. An example is
of the dreamtime community who resided in the region known as the “hairless ones”, who were believed
to have drank bore water from the underground bore now known as the Hurray Sandstone Formation.
The Kooma peoples respect for their ancestors, the traditional owners of the land, creates a sacred bond
with the groundwater of the area. Like most of the features of the land, the Kooma people endeavour to
preserve this natural resource in respect for the land and for their ancestors. The indigenous people also
place great value on natural features that provide life and habitat to all creatures of the land. One major
example is the Nebine creek, which flows 40kms through the Kooma properties, a major provider for the
local eco-system.
As well as preserving landmarks of cultural significance, KTOAI are also working towards a vision for
their community that promotes growth and development within the Kooma people. The vision is of a
community where members are encouraged to return to the site to experience the facilities and the
cultural renewal. This concept includes a business based on eco-tourism, where accommodation is
supplied for guests interested in learning about the indigenous culture of the outback area. Cultural
exchange is a major part of building mutual respect between cultures and encouraging healthy
relationships between communities.
Design Specifications
When undertaking a project for a community where the cultural beliefs are as significant as in the
Aboriginal community of the Kooma nation, extensive precautions must be taken to ensure all beliefs and
traditions are considered during the design process. Right from the initial discussion on design area,
consideration was given to the immediate needs of the culture and where the project could be of
assistance. Providing a sustainable water source that relieved the heavy dependence on the groundwater
appeared an excellent foundation for the cultural vision. Furthermore it encourages the constant flow of
tourists, confident of a safe, and educational visit.
Design of the water tanks coordinates the average water usage expected of the site with the annual
rainfall at Bendee Downs. With approximately 200m cubed of water falling on the available catchment
area at the site annually, and the expected usage to be around 160m cubed a year, there is likely to be
overflow during the heavy wet season. Provisions have been made in the design to allow for overflow of
the tanks to be directed to the nearby wetlands to supply surface water and encourage groundwater recharge. This design component supports KTOAI activities in natural resource conservation.
Before implementation of the proposal, members from the design team would meet with elders from the
community to present the design and discuss its compliance with the cultural manners of the community.
Options for cultural education within the proposal would be suggested to the elders and opinions called
for. Such options are allowing local indigenous artists to use the exterior of the water tanks as a canvas
for artwork, thus promoting art within the community and education for tourists visiting Bendee Downs.
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Economic
Materials
The economic impact of the proposed water supply system is reasonably cost effective considering the
magnitude and sustainability of the design. The tanks are made of polyethylene, coming with 25 years
warranty. Research has shown that this type of tank is durable and long lasting in extreme weather
conditions. The cost of the polyethylene tanks is lower than that of other materials such as concrete or
steel. It costs approximately twice the amount to get a concrete tank of the same size and six times that
for a steel tank. Furthermore, polyethylene doesn’t come with the same problems that are common in the
concrete and steel; it is more resistant to cracking and corrosion. The light weight nature of tanks also
makes them easy to transfer over long distance. The sensor units cost $220 each with a $50 freight
charge. Compared to other brands, the sensors sourced for implementation are the most economically
viable in the market. The decision to include a pressure tank eliminates the dependence on continual
pumping, thus greatly decreasing energy consumption and costs. The guttering is made of aluminium and
lasts as long as the more expensive counterparts such as copper or steel, costing only a fraction of the
price.
Figure 2.0 – Graph of Material Percentage Costs
ITEMS
COST
TANKS FROM ACCOMMODATION
$9000
TANKS FROM SHEARING SHED
$21000
PRESSURE TANK
$1350
PIPE
$315
PUMPS
$170
SENSORS
$490
GUTTERING
$700
SUM (APPROXIMATE)
$33, 000
Table 1.9 – Costs of Materials for Rainwater Catchment and Storage System
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Labour
In order to complete the installation and piping, 2 labourers need to be hired. The installation of tanks at
the shearing shed and accommodation will take two day to be completed. The pressure tank, sensors and
pumps will take another day to be installed. Piping starting after the installation of the tanks requires 3
days to be completed, costing approximately $1920, including excavation and refilling. The sum of the
installation costs is approximately $3840.
Labor versus Materials
Labor Material
23%
77%
Figure 2.1 – Graph of Labour versus Materials Costs
EVENT
LABOUR DURATION COST
INSTALLATION OF TANKS AT ACCOMMODATION 2
1 DAY
$640
INSTALLATION OF TANKS AT SHEARING SHED
2
1 DAY
$640
INSTALLATION OF PRESSURE TANK AND PUMP
2
1 DAY
$640
PIPING
2
3 DAYS
$1920
SUM
13
11 DAYS
$3840
Table 2.0 – Labour Costs for Rainwater Catchment and Storage System Implementation
Total Economic Impact = $38,000
32
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Environmental Effects Statement
Summary
Engineers Without Borders has called for proposals on developing/restoring the cultural site of Bendee
Downs, in Kooma Traditional Country, South-west Queensland, Australia. In order to be considered, the
design in question must be environmentally sound, technically feasible, culturally approved and
economically reasonable. This means low cost and maintenance, plus minimal impact on the culture and
surrounding environments.
Proposals
Water Supply was selected as the Design Area for this project. Three main designs were considered, their
benefits and detractions evaluated, before Rainwater Catchment and Storage was chosen to be the best
development plan as it rated higher in cultural acceptance, minimal maintenance and sustainability. (See
Figure...)The advantage of our chosen design is that we are utilising the high level of rainfall received in
the area and the large roof catchment areas and thus eliminating the unsustainable reliance on
groundwater for drinking, cooking and shower usage.
Community Consultation
In order to gain the Kooma Nation cultural community’s approval on the rainwater catchment and storage
development designs in question, a number of consultations will need to be organised. Some of which
include:
•
•
•
33
A Land Trust must be directed before any building or infrastructure work can take place on
Aboriginal land. For this to happen, the traditional Aboriginal Owners, being the Kooma
Traditional Owners Association Incorporated (KTOAI), must consent to the project proposal as a
group and be consulted on any influencing aspects of the design.
- An effective way to consult the community is to form a Community Advisory Committee to
represent KTOAI
Site visits will be conducted where further consultation with KTOAI and the residents of the
property can occur and they can contribute to the design and implementation of the proposed
project.
The local community may wish to become involved in the installation of the design, as well as the
maintenance of the gutters and filters. An educational workshop will be conducted as well as
formal instructions provided on how to maintain the rainwater catchment and storage system.
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Materials and Associated Impacts
Guttering
As aluminium guttering has the longest lifespan for its cost, coming with a 25-30 year warranty, it is a
sustainable option when compared to vinyl or galvanized steel. Also secondary-aluminium guttering can
be sourced which is comprised of recycled aluminium, and hence re-using our natural resources.
Water Storage Tanks
While the chosen polyethylene tanks aren’t biodegradable and are comprised of petrochemicals, they
have the longest lifespan, and therefore are the most sustainable option. These tanks can also be re-cycled
when they are no longer useful. As the land is so flat and barren at Bendee Downs no levelling will be
required. Also, as the soil is quite sandy and dusty it provides a suitable surface for the tanks to be placed
on, eliminating the requirement for concrete foundations.
Excavation and Piping
Excavation processes due to the required piping will have minimal, if any impact on the environment, as
there is barren land between the shearing shed and accommodation (see google earth image). Careful site
analysis has proven that no flora or fauna relocation will need to result from the proposed excavation, and
no habitats will be harmed. The trench runs for approximately 100m, and is 30cm deep. Polyvinyl
Chloride piping is non-biodegradable, but can however be recycled.
Pump
The 2 pumps that will be implemented as part of the system are small, and non-invasive. One is a battery
operated pump which runs on 2 x D battery cells and the other is a 240V electrical pump which will be
connected to the generator. As electricity bills are already exceptionally high at Bendee Downs this
proposal has been designed to use as little power as possible, tending to rely more on gravity for pressure.
Float Switch
The float switch is very environmentally sound as it switches the pumps on and off accordingly, as
opposed to it running constantly and using more electricity than the pumps require. In addition, the
mechanism chosen contains no mercury, and is simply operated by a ball and lever mechanism.
Summary
This rainwater catchment and storage system design has very little mechanical components associated
with it. Apart from the 2 pumps, the system relies on the basic principles of fluid mechanics. In addition
each of these materials and components listed above have been sourced locally, which dramatically
decreases the carbon dioxide emissions associated with the transport of the overall system.
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Group 7A – 2010 EWB CHALLENGE
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Impact Management
An impact minimisation and management program will be implemented as part of the contract in this
development. It is important for all parties that this project is as sustainable as possible. Some
responsibilities will include:
•
•
•
•
Seeking approval from KTOAI through every step of the design and installation process
Community education on how to maintain the water supply system put in place
Careful site and local environment analysis
Continued contact upon completion of the proposed project to ensure full satisfaction from the
residents and to address any issues that may present themselves
Conclusion
The Bendee Downs site development proposals outlined in this report adhere to the constraints set out by
Engineers Without Borders. The selected design endeavours to enhance the water supply system in a
sustainable, culturally embracing manner, with little, if any impact on the local environment. The chosen
alternative has been designed to be the most environmentally sound, technically feasible and
economically reasonable water supply option available. The preliminary site analysis conducted between
19/07/10 and 16/08/10 highlighted the obvious considerations and constraints of construction at Bendee
Downs. Research and data analysis supported and justified the reasoning behind the chosen design
option. This involves the design and implementation of a rainwater-harvesting and storage system to
accommodate the predicted influx of visitors to the site (averaging 20 people per day). The water
collected will be used for consumption, cooking and showering. The rainwater will be collected from the
shearing shed and accommodation via guttering and will then be filtered into storage tanks. Piping
between the buildings will pump the water from the shearing shed to be used at the accommodation. A
2000L capacity tank, elevated 3m on a steel structure, will be installed to sufficiently pressurise the
water. Having completed an impact assessment and environmental effects statement, the economical,
environmental, social and cultural benefits of this development are tremendously high and will be an
extremely sustainable development for the KTOAI.
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Group 7A – 2010 EWB CHALLENGE
5/10/2010
References
General
www.meond.net/greywater.html
www.thewatertreatments.com/
http://hubpages.com/hub/Composting_ToiletsNot_Just_For_Cabins
Site Investigation
http://www.exploroz.com/Places/39464/QLD/Bendee_Downs.aspx
http://www.googleearth.com
Bureau of Meteorology
http://www.bom.gov.au/jsp/ncc/cdio/cvg/av?p_stn_num=044010&p_prim_element_index=18&p_display
_type=statGraph&period_of_avg=ALL&normals_years=allYearOfData&staticPage
Guttering
http://www.articlesnatch.com/Article/5-Advantages-Of-Aluminium-Gutters/1574877
http://www.whatprice.co.uk/building/guttering.html
http://www.alcoil.com.au/aluminium-guttering-products.html
http://www.servicemagic.com/article.show.Which-Gutters-Are-Best-for-Your-Home.13972.html
http://www.acleanergutter.com.au/index.php?option=com_content&task=view&id=7&Itemid=7
Water storage tanks
Guidance on Use of Rainwater Tanks, enHealth Council, Publications Production Unit (Corpotate
Support Branch). Australian Government Department Of Health and Ageing, Australian Government
2004
Filtration
http://www.awqc.com.au/AWQC/AS4020/
http://www.rainharvesting.com.au/benefits_of_first_flush_water_diverters.asp
http://www.rainharvesting.com.au/FileLibrary/product_spec_first_flush_postwall.pdf
www.yourhome.gov.au/technical/fs73.html
http://www.reuk.co.uk/First-Flush-System-Rainwater-Harvesting.htm
Piping
Pumping
http://www.swim-in.com.au/p/battery_operated_water_pump_-_empty_fish_ponds_etc
http://www.pir.sa.gov.au/pirsa/nrm/water_management/pump_maintenance
http://www.clicktobuy.com.au/store/240v-water-pressure-pump-17-lmin-suit-sea-water-wine-etc-p135.html
Float Switch
Cultural
http://www.fermor.com.au/default.htm
http://www.clc.org.au/Ourland/land_rights_act/aboriginal_land.html
http://www.regionalartsnsw.com.au/ebulletin/2009/july.html
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Group 7A – 2010 EWB CHALLENGE
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Appendix
Figures
Figure 1.0 - EWB Challenge 2010 Logo
Figure 1.1 – KTOAI and EWB at Bendee Downs
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Group 7A – 2010 EWB CHALLENGE
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Figure 1.2 – Google Earth Image of Bendee Downs Site
Figure 1.3 – Murra Murra and Bendee Downs Location (28° South, 146° West)
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Group 7A – 2010 EWB CHALLENGE
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Figure 1.4 – AutoCAD aerial view of proposed water supply design
Figure 1.5 - AutoCAD aerial view of guttering at Accommodation
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Group 7A – 2010 EWB CHALLENGE
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Figure 1.6 - AutoCAD aerial view of guttering at Shearing Shed
Figure 1.7 - AutoCAD design of tanks at accommodation
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Group 7A – 2010 EWB CHALLENGE
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Figures 1.8 – Diverter System Selected for Implementation at Bendee Downs
Figure 1.9 – Artist John Weeronga Bartoo, descendant from the Kooma tribe
Figure 2.0 – Graph of Material Percentage Costs
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Group 7A – 2010 EWB CHALLENGE
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Figure 2.1 – Graph of Labour versus Materials Costs
Tables
Table 1.1 – Average Maximum Temperature at Bollon (1907-2010)
Statistics
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Years
Mean
35.5 34.3 32.0 27.8 23.0 19.5 19.0 21.4 25.6 29.6 32.8 35.0 28.0
99
maximum
temperature
(°C)
for
years 1907
to 2010
Table 1.2 – Average Minimum Temperature at Bollon (1907-2010)
Statistics
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Years
Mean
21.5 21.0 18.2 13.2 8.7
5.7 4.2 5.6
9.2 13.7 17.2 19.9 13.2
97
minimum
temperature
(°C) for years
1907 to 2010
Table 1.3 – Average Rainfall at Bollon (1885-2010)
Statistics
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Years
Mean
63.1 53.4 49.9 31.6 32.7 29.9 27.8 22.3 24.5 35.3 40.8 52.2 463.4
125
rainfall
(mm)
for
years 1885
to 2010
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Group 7A – 2010 EWB CHALLENGE
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Table 1.4 – Specification of polyethylene tanks to be installed at shearing shed
SHEARING SHED TANKS
Number of tanks
required
Capacity
3
Diameter
4630mm
Inlet height
3170mm
Total height
3400mm
Unit cost
$6930
46, 817L
Table 1.5 – Specifications of polyethylene tanks to be installed at accommodation
ACCOMMODATION TANKS
Number of tanks required
2
Capacity
31, 822L
Diameter
4100mm
Inlet height
2540mm
Total height
2730mm
Unit cost
$4310
Table 1.6 – Specifications of polyethylene pressure tank to be installed at accommodation
PRESSURE TANK
43
Number of tanks required
1
Capacity
2, 000L
Diameter
1300mm
Total height
2000mm
Unit cost
$650
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Table 1.7 – Specifications of chosen lever switch
Price:
$220 each
Freight:
Model:
$50
Kelco Pty Ltd.
Brisbane
K Series
Warranty:
12 Months
Source:
Table 1.8 – Environmental Pros and Cons of Rainwater Catchment and Storage at Bendee Downs
Pros of rainwater catchment and storage
Decreases reliance on the unsustainable
groundwater source.
Excess water stored can be used for
irrigation, lessening the degrading impact
that the mineral-rich groundwater from the
Wyandra Formation is causing.
Promotes sustainability and environmental
awareness in the community.
By sourcing tanks and other materials
locally, greenhouse gas emissions will be
greatly reduced.
Site analysis has confirmed that the
excavation required will not impact any
habitats, flora or fauna.
While polyethylene tanks are nonbiodegradable, they are recyclable.
Secondary aluminium guttering can be
purchased which is comprised of recycled
aluminium.
44
Cons of rainwater catchment and storage
Aesthetics of multiple, large tanks.
PVC pipes, non-biodegradable.
Polyethylene tanks, non-biodegradable.
Excavation for piping.
Aluminium for guttering.
Transport of materials to the remote location of
Bendee Downs.
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Table 1.9 – Costs of Materials for Rainwater Catchment and Storage System
ITEMS
COST
TANKS FROM ACCOMMODATION
$9000
TANKS FROM SHEARING SHED
$21000
PRESSURE TANK
$1350
PIPE
$315
PUMPS
$170
SENSORS
$490
GUTTERING
$700
SUM (APPROXIMATE)
$33, 000
Table 2.0 – Labour Costs for Rainwater Catchment and Storage System Implementation
EVENT
45
LABOUR DURATION COST
INSTALLATION OF TANKS AT ACCOMMODATION 2
1 DAY
$640
INSTALLATION OF TANKS AT SHEARING SHED
2
1 DAY
$640
INSTALLATION OF PRESSURE TANK AND PUMP
2
1 DAY
$640
PIPING
2
3 DAYS
$1920
SUM
13
11 DAYS
$3840
Group 7A – 2010 EWB CHALLENGE
5/10/2010
Appendices
APPENDIX A – Average Maximum Temperature in Bollon
APPENDIX B – Average Minimum Temperature in Bollon
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APPENDIX C – Average Annual Rainfall in Bollon
APPENDIX D – Grey Water Filtration System
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Group 7A – 2010 EWB CHALLENGE
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APPENDIX E – Slow Sand Filtration
APPENDIX F – Design Selection Matrix
Sustainability
Cultural
Approval
Cost
Maintenance
Sum
Grey water
3
4
3
2
12
Composting
toilet
4
2
4
3
13
Rainwater
catchment and
reuse
4
5
2
4
15
APPENDIX G – Composting Toilet System
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Group 7A – 2010 EWB CHALLENGE
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APPENDIX H – Groundwater Considered Sacred by KTOAI
“The main bore at the Bendee Downs house accesses the Hurray Sandstone Formation (550m). This bore
is under greater pressure than the other property bores and the water is fresher. It has been used for
human consumption since the bores were drilled over a century ago. The dreamtime of the region refers
to an Indigenous community called the “hairless ones”. This community was known to drink the bore
water, which may present a barrier to its use as an ongoing water supply.”
– p26, EWB Challenge 2010 Report
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Group 7A – 2010 EWB CHALLENGE
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APPENDIX J – Aluminium Gutter
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APPENDIX M – Polyethylene Tanks to be installed at Bendee Downs
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APPENDIX P - Product testing to AS/NZS 4020:2005
Testing of Products for Use in Contact With Drinking Water
The Australian Water Quality Centre was the first laboratory in Australia to offer testing to AS/NZS
4020. The Standard is designed to test any product that comes in contact with drinking water. The
AWQC also provides testing to equivalent International Standards (eg BS6920)
The first products were submitted to the AWQC in 1992 and since that time the laboratory has tested well
over a thousand products. Enquires and products have been received from all states of Australia, Asia,
New Zealand, United States and Europe.
Certificates of testing issued by the laboratory are recognised by Standards Australia and the major Water
Authorities. NATA accreditation has been obtained for all the tests described in the Standard.
- http://www.awqc.com.au/AWQC/AS4020/
APPENDIX Q – Estimated Pollution Factor for Bendee Downs derived from table below
-
52
http://www.rainharvesting.com.au/FileLibrary/product_spec_first_flush_postwall.pdf
Group 7A – 2010 EWB CHALLENGE
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APPENDIX R – First Flush Diverter System for implementation at Bendee Downs
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APPENDIX T – AutoCAD design of float switch operation
APPENDIX U – Kooma Tribe Cultural Art
John Weeronga Bartoo is back at the Inverell Art Gallery from 4 to 27 July with an exhibition entitled
Dreamtime Walkabout. John was born in Brisbane and is descended from the Kooma tribe from South
Western Queensland around St George and Cunnamulla. His paintings are held in private collections in
Australia, Austria, Canada, China, England, France, Italy, Germany, Hong Kong, Japan, New Zealand,
Scotland, Taiwan, The Netherlands and the USA.
- http://www.regionalartsnsw.com.au/ebulletin/2009/july.html
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