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Water Harvesting


A Story Of Three Schools Taking The Lead

The following three cases involve schools in South Australia from different geographic areas and different climate, but each with the same strategy.

The strategy? To harvest, store, and re-use runoff from roofs and hard surfaces. Schools not only have substantial roof areas to collect rainfall, but they also have relatively large paved and sealed surfaces that can yield very useful volumes of rainfall runoff.

Looking back at my involvement in the design of each system, it is interesting to note that ...

  • one was at the start of the millennium drought (2001)
  • one was about in the middle (2007), and 
  • one was towards the end (2009)

Schools have the scope to become almost self-sufficient in three core services;

  • water (potable and irrigation water)
  • wastewater
  • energy

There are some fine examples of how schools have adopted elements of sustainability, but there is always room for continual improvement. 

This page is about water harvesting for irrigation and the following examples depict what can be achieved with some forward-thinking and the right approach.


Site 1 - Clare High School

Located in the heart of the wine, grain, and wool producing region of the Mid North of South Australia, and about 140 km north of Adelaide, Clare High School was an early adopter in 2000 and 2001 of grid-tie solar power and water harvesting respectively. I was involved in both projects.

The objectives of the water harvesting project were :

  • to reduce the school's dependence on mains water (Murray River water)
  • to use, and to add value to, what has been a waste resource - i.e. rainfall runoff - and to establish productive systems accordingly
  • to integrate outcomes with other programs in the school, particularly productive agricultural and viticultural systems

The strategy involved :

  • collecting as much runoff as possible and transferring it to the existing pipe drainage system
  • storage of runoff in two dams, the smaller of the two to discharge to the larger by pumping
  • stored water to be re-used as irrigation water on the school's vineyard

The methodology that was developed for the site involved :

  • determining the areas of the various parts of the overall catchment
  • examining annual rainfall records  
  • estimating average annual runoff to determine the size of water storage dams
  • preparing plans of the dams

This project has been established since 2002.


Site 2 - Unity College (Murray Bridge)

Located about 76 km east of Adelaide and near the Murray River, Unity College has a strong focus on sustainability and the environment.

This project involved two components - wastewater management and stormwater harvesting. The wastewater management aspect is described in a different section.

The objectives of the project were :

  • to reduce the College's dependence on mains water thereby leaving more water in the stressed Murray River 
  • to implement water-sensitive design and optimise the value of the College's water resources
  • to enhance environmental management values on the property

The strategy involved :

  • collecting as much roof runoff as possible and storing it in rainwater tanks for potable use
  • transferring other hard surfaces runoff and excess roof runoff to the existing drainage system
  • storage of runoff in a dam that will be used as a constructed wetland for environmental purposes

The methodology for this site included :

  • determining the areas of various parts of the overall catchment
  • examining annual rainfall records  
  • estimating average annual runoff to determine the size of the water storage dam
  • preparing plans of the dam

The project was completed in 2010.

The report that was prepared for this project was written so that it could be used as a teaching aid suitable for an environmental syllabus.


Site 3 - Booleroo Centre District School

Booleroo Centre is a small town located about 280 km north of Adelaide in a traditional grain cropping and sheep grazing area. Booleroo Centre District School serves a wide rural area, and has adopted a sustainability focus.

The objectives

The water harvesting project began with a key objective being to achieve self-reliance in water as much as possible and to reduce the reliance on Murray River water. It was estimated that the transported water cost to the school was $20,000 annually, and this cost was projected to rise substantially in future years.

The strategy involved :

  • transferring as much excess roof runoff (once rainwater tanks were full) and hard surface runoff as possible to a pipe drain system
  • filtering gross pollutants and other contaminants in a reed bed system
  • storage of filtered water in a dam
  • re-use of the stored water on to existing irrigated areas 

The methodology that was developed for the site involved :

  • determining the areas of various parts of the overall catchment
  • examining annual rainfall records
  • adopting "The Simple Method" to estimate average annual runoff 
  • determining the optimum size of the water storage dam and preparing plans
  • designing the reed bed constructed wetland system
  • estimating the project cost

The project was completed in 2010.

The following photos describe the system as it was in 2014.

P1060745


Entry through the reed bed into the storage dam (south end)


P1060746






A view of the water storage dam (north end)


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