Summary

Did you know that Platypus still live in the Plenty River? However urban development is threatening their survival for a number of reasons:

too much stormwater enters the Plenty river when it rains.
too much litter is washed into stormwater drains and then into the Plenty River
sediment is washed into the stormwater drains and then into the Plenty River making the water dirty
vegetation along creeks is being washed away and not replanted
climate change is leading to more droughts and more floods

But there is hope. There are many things we can do in our home to reduce stormwater flows. This lesson about how to protect the Platypus will teach you what you can do at school and at home.

Learning Objectives

Learn about where platypus are found in the Plenty river.
Learn what is affecting the health of the platypus.
Learn what you can do at home and school to help save the platypus.

Where is the platypus in the Plenty River?

Platypus are found all along the eastern side of Australia. They are unique to Australia and we need to protect them forever because they are such as strange looking animal. They have a nose like a duck's beak, webbed feet, and fur all over their bodies. They also lay eggs. They are part of a specialised mammalian family known as the monotremes. There are a key predator species in our waterways and love to eat all sorts of waterbugs, yabbies, worms.

There are only a few platypus remaining in the plenty river. You can find out where the have been recently spotted using the PlatypusSPOT web site.

Many people regularly go out looking for these shy little creatures and then report them on the PlatypusSPOT web site. They note the location they found the platypus and upload photos too. These reports give scientists and government agencies vital information about the whereabouts of platypus. You can see from the map that we still have at least once recent sighting in the Plenty river.

In addition to visual sightings scientists and researchers are using Environmental DNA (eDNA) techniques to see if a platypus has recently been in a local waterway. Platypus, like most animals, will shed some of their cells when they move through the water. These small fragments of DNA can be amplified up. The technique is sensitive enough to pick up the presence of a platypus within several hundred meters of the sample site.

What is affecting the health of the Platypus?

Whenever we build a new housing estate we always build roads and put stormwater pipes below ground. When houses are built they all have roofs, driveways and people may even pave the ground and add sheds or pergolas. All of these elements have one thing in common - they all create stormwater runoff.

Stormwater runoff is the water that runs off a surface when it rains. Before housing estates were built most of the rain that fell stayed local. It would gather on the ground in puddles and then slowly seep into the ground. Once in the ground the water would be used by plants. Grasses and shrubs can use water close to the ground. Trees can extract water from deep under the ground.

Normally there is too much water in the ground and this contributes to the greater pool of ground water flows. Think of groundwater as an underground river. Groundwater has an important role to play in waterway health. Groundwater flows slowly, but more or less constantly. Groundwater also leaks out into waterways and creates what are known as base flows. About 50% of the water running in stream is made up of these base groundwater flows.

Building houses and roads has changed the natural balance of water flows (also called the hydrological cycle). Trees that once relied on rainwater start becoming water stressed. Aquatic animals that lived happily in waterways start experiencing storm surges (large flows of water during rain events).

When houses and roads are built lots of earth is dug up. Without grass and trees to hold the soil in place it can easily get washed away. The soil also enters stormwater pipes and enters into waterways. Some soil is so fine that it makes the water very dirty or turbid. Other soil particles that are larger and heavier form a layer of silt at the bottom of waterways. All of these effects are bad for the animals and plants living in water system. Some of the soil also carries nutrients that can trigger to growth of harmful algae. The poor animals living in waterways cant see their food. Algae and silt in the water can remove oxygen from the water and clog the gills of fish.

Litter dropped on roads or blown on the wind can now easily find their way into waterways because the litter gets washed into stormwater drains when it rains, and this takes the litter directly to waterways. And the litter doesn't stop in waterways, it continues to the ocean.

You may be asking the question - Well who designed this silly stormwater system? Stormwater pipes were originally invented to help prevent localised flooding. At the time they were invented cities and towns were small. The impact of adding stormwater pipes was minor and most people didn't think about the effect the added stormwater would have on aquatic animals.

How to protect the platypus in schools

Schools have a critical role in demonstrating different techniques that can be applied to protect the platypus. Young people have a vested interest to understand and apply these techniques at school and also at home.

Convert rainwater tanks to Smart Tanks

Most schools have rainwater tanks that were installed during the Millennium drought (1998 to 2008) or as a part of the ResourceSmart Schools program. Even though the rainwater tanks are used for toilet flushing, they stay full of water most of the time.

School rainwater tanks can be converted to Smart Tanks by installing water level sensors so the fill level of the tanks can be monitored. In addition to flushing toilets, tank water can be used to water vegetable gardens, native gardens, productive trees, top up frog bogs and irrigate seedlings in nurseries.

As a final measure the Smart Tank and receive Bureau of Meteorology (BoM) weather forecasts about rain events up to 7 days in advance. This allows the tank to release water in an irrigation system or directly to stormwater so that it can receive new rainwater without over flowing. Smart Tanks help protect platypus by reducing large stormwater inflows to waterways and by recharging ground water (ground water flows gently feed base water flows in waterways).

Tank water should always be checked to make sure it is clean and free of bird dropping and leaf litter debris. Regularly inspect gutters and roofs. Once every few years the tank needs to be fully drained so that sludge can be cleaned out from the tank.

Make a Frog Bog

Tank water is free of chlorine and salts because it comes directly from the sky. This makes it an excellent water source to keep frog bogs filled up year round. Frogs need water, shelter and food to survive. A Frog Bog is easy to make and can provide all these elements to attract frogs.

Frog bogs also help water to infiltrate into the ground to replenish groundwater. Plants in and around frog bogs are the same as those planted around waterways.

Local friends groups can help a school design and build a frog bog. Click on this video link to see how to build a frog bog appropriate for a school environment.

Gardening Australia - Frog Bog

Plant a food forest

Growing food locally uses less water than most commercial agriculture operations and can create more habitat opportunities for local animals. Agriculture extracts water from local rivers where animals such as platypus live. Growing food at school and home uses roof water as the main source of water. Watering garden beds reduces stormwater flows to waterways and replenishes ground water flows that feeds waterways.

It doesn't take much space to create a food forest. Bill Mollison (one of the co-creators of Permaculture) recommends planting a 4m2 vegetable plot (e.g. 1m x 4m) and to plant ten productive trees (for oils, citrus, nuts and preservable fruit). In total, this garden can provide 40-60% of a person's vegetable needs (Permaculture - A Designer's Manual p65).

Food forests have up to 7 levels of plant growth.

Canopy (large fruit, nut and native trees such as lilly pilly trees)
Low tree layer (dwarf fruit trees and natives)
Shrub layer (currents and berries)
Herbaceous layer (comfreys, beets and herbs)
Rhizosphere (root vegetables such as turnips, carrots, parsnips)
Soil surface (ground covers such as strawberries, midgen berries)
Vertical layer (climbers and vines, e.g. grapes, passion fruit)

A forest garden attempts to replicate the beneficial arrangements we see occurring in nature. The diverse habitat of food forests brings in a range of beneficial insects and other animals. Prunings and leaves can also be laid down to create a nutrient rich mulch.

Grow seedlings and plants in a greenhouse

Schools can produce many of their own seedlings if they have a plant nursery or greenhouse. The seedlings can be:

Used for community planting days.
Given to students to plant at home.
Planted in native gardens at school.

Humanity has cleared nearly half of the planet's natural forests. Its time to give back and restore forests and the habitat they provide for billions of animals. Re-wilding and Caring for Country are important activities that humanity will need to adopt over the next 100 years to restore natural ecosystems.

Schools can showcase native gardens and host community planting days to revegetate waterway corridors and parks. This will provide young people and the community with vital training.

View the short video on the web site Our Planet narrated by David Attenborough which gives guidance on re-wilding the planet by planting trees, forests and other vegetation How to rewild our planet

How to protect the platypus at home

We have identified that stormwater running into waterways is having a negative effect on the survival of the platypus. So what can we do about reducing the amount of stormwater entering waterways from our home? Here are some simple ideas you can apply from home.

Install a rainwater tank

The best thing you can do is to install a rainwater tank at home. The bigger the tank the better. We should all aim to install a 20,000 litre rainwater tank.

Why such a big tank?

If we have a big enough rainwater tank we can capture as much water as we use from the tap. Let's do some maths.

The roof area of a typical house is 150m2.
The average amount of rain in a year is 650mm
Therefore the roof should be able to capture 150 x 650 = 97,500 litres of water per year. Ignoring losses.
The average person uses 155 litres of water per day. In a year that is 155 x 365 = 56,575 litres.

These calculations show that a typical house should be able to provide the daily water requirements for 2 people. And if we make a few changes to the way we use water a typical house could produce enough water for perhaps 3 or 4 people.

Now rain doesn't fall in even amounts all year round. To even out those differences we need to store enough water to last us between rain events. We also need a big enough tank to capture those seriously big rain events. Big rain events are normally described as one in one-hundred year events (one in one-thousand year events are even rarer, but do happen). Climate change is making these rare rain events more common because the atmosphere has heated up and the warmer atmosphere carries more moisture.

Flooding and Climate Change

On 29 December 2016 Lalor experienced an 89 mm rainfall event which flooded roads and waterways. The event was later calculated to be a one in five-hundred year event. Events such as this are going to become more common in the future due to Climate Change.

If we take the typical roof area of a typical house (150m2) this rain event would create 150 x 89 = 13,350 litres of water runoff. Having a 20,000 litre tank would mean that most of this water could be retained on site. Retaining water in a tank reduces localised flooding and stops stormwater from rushing to our local waterways.

Some of you may ask the question - But what if the tank is already full? To answer this question we need to introduce the new concept of Smart Rainwater tanks.

Smart rainwater tanks

Smart Rainwater Tanks are able to predict rain events up to 7 days in the future. They do this by looking up the weather forecast on the Bureau of Meteorology web site (just like you would check the weather using your mobile phone).

Weather reports tell us:

when rain is predicted
how much rain is expected
and the certainty of the prediction (or the error in the prediction).

With all this information a Smart Tank can make some educated guesses on how to prepare for the next rain event.

The Smart Tank can gradually empty to make some room for the future rain event. It can also notify the household that rain is coming and let the owners decide how they will use the tank water.

The best way to use tank water is to water plants and let most of the water soak into the ground. If the ground is already fully saturated, then excess tank water can be released to waterways. Both of these actions reduce peak flows in waterways.

The best thing about Smart Tanks is that you can build them yourself. You only need a few components. And if you want to use even less technology, then all you need to do is add a level gauge to your tank and follow the local weather reports.

Downpipe diverters

Some people don't have room to install a rainwater tank. In the future when we get rid of most cars and use share cars or public transport, we will all have extra room in our garages for large rainwater tanks. In the interim, you can always add a downpipe diverter which will direct any roof water to your garden. Roof water is best diverted into a mulched area of the garden which can allow the water to infiltrate into the ground. You can also create a swale so that water can collect and then infiltrate. Plant trees in infiltration areas. As trees grow the tree roots make the ground even more permeable.

Mulch your garden and plant trees

Some soils allow water to infiltrate much better than others. Water can easily infiltrate into sandy soils, whereas clay soils slow the rate of water infiltration. But clay soils also hold more water than sandy soils.

Tree roots penetrate deep into the soil. This action helps to open up soils making it easier for water to penetrate. Mulch on the surface and in the top layers of soil is generally more porous, allowing water to penetrate into the upper layers of soil more easily.

A backyard well planted with trees with a layer of organic mulch (wood chips, plant cuttings, leaves) will increase the amount of water infiltrated into the soil. Please don't put cuttings in the green bin. They more mulch and vegetation cover you have in the your garden the better the water infiltration. In summer the mulch and tree cover will also keep your garden cooler and help retain more water in the soil.

Organic mulch will eventually help to break up heavy clay soils. If you want to speed up this process you can add gypsum.

Grey water diversion

During the Millennium drought all households in Melbourne were placed on severe water restrictions for multiple years. Households had to minimise water usage inside the house, and also how often gardens were watered. To help save the plants in the garden many people diverted grey water from showers and the laundry to the garden. Grey water is the term we use for wastewater from showers, baths, wash basin and washing machines. Black water is the term used for wastewater from toilets.

Even when we are not in drought we can still use grey water on the garden. When using grey water you need to be careful about the shower and laundry products you are using. Choose produces that are biodegradable or made from 100% natural ingredients if possible. Phosphates in detergents (which act as fertilisers) and salts should be avoided or minimised. Bleaches and brighteners added to the wash cycle are also harmful to microorganisms in soil.

Wash in the shower using a bar of soap that you can buy from a Health Food store.

Wash clothes using soapnuts or soapberries which are the fruits of the Sapindus Mukorossi tree. This tree grows naturally in the foothills of the Himalayan mountains.

Use less water in the home

All the water that comes out of our taps at home (also called potable water or drinking water) comes from natural waterways or forests that act as catchments. Cities extract large amounts of water from nature to sustain themselves. From natural water reserves, 70% of the water is used for agriculture, 20% is used by cities as tap water - leaving only 10% for waterway systems and the animals and plants that depend on this water.

So every drop of water that you save at home will mean that less water needs to extracted from waterways.

Some simple things you can do at home include:

Have a 2 minute shower
Catch the shower water (also called grey water) and using it to water the garden. Make sure it is garden safe.
Use rain tank water for the washing machine
Use rain tank water to water the garden
Economise on household water use (both tank water and tap water) when the rainwater tank is low. A low rain water tank means that the environment has not received sufficient rainfall recently.
Don't wash cars or foot paths. Washing cars on the street sends waste water directly into stormwater pipes and into waterways.

Litter

The connection of stormwater pipes from roads to waterways results in litter entering platypus habitat. Stormwater pipes are connected to the stormwater drains (side entry pits) on most roads. Litter on the ground is carried on the wind and ends up on the road and then with rain events the litter washes into the stormwater system. Even litter carefully placed in rubbish bins can enter waterways because during collection some litter inevitably drops to the ground. Local activities that generate litter are:

Take away food packaging.
Packaged food items from supermarkets.
New products and the associated packaging.
Construction works for new houses and buildings.

Platypus become entangled in plastic and rubber items (e.g. rubber bands, hair ties). They can also mistakenly ingest microplastics and degraded plastic. The litter items in waterways are eventually washed into the ocean. Today there is thousands of tonnes of litter that get washed into the ocean every year.

There are several interventions that can help:

Stop buying single use packaged items.
Reduce consumption to the bare essentials.
Conduct a weekly audit of all your rubbish and recycled bins and find our ways to reduce all rubbish.
Disconnect stormwater pipes from roads.

One family in Tasmania has been successful is becoming a zero waste household. They do this by:

Buying food in bulk from special stores.
Bringing reusable containers and bags to shops.
Buying locally grown food from the farmers market and growing their own food.
Composting their food scraps in compost bins and worm farms.
Buying secondhand clothes made from natural fibres that can be composted at end of life.

Happen Films - How a family of 5 make almost zero waste

Silt and New Home Construction

All new urban developments use heavy earth moving equipment to put in underground utilities (sewerage, water, gas, electricity, recycled water, stormwater, NBN). Roads are constructed and immediately connected to stormwater pipes. Unprotected soils are vulnerable to erosion during rain events.

Smaller, modular housing placed on stumps can reduce the total area disturbed by on-site construction. Services could be reduced to the provision of tap water and micro-grid electricity if the following household changes are made:

Waterless composting toilets used in place of conventional toilets.
Bottled gas used for cooking (no gas for heating water or heating building envelopes). No connection to gas mains.
4G and 5G used for home telecommunications rather than cable to the home.
Large rainwater tanks (20,000 litres) installed on all houses. No stormwater pipes.
Street or community micro-grids installed using community batteries Victorian Government - Neighbourhood batteries. No connection to main grid.
Solar street lighting.
Common car park for residents (under cover). No roads for cars, or driveways or garages within the estate. Only walking paths wide enough for the intermittent use of emergency vehicles.
Houses only occupying 50% of land area (especially on the house block or lot). This is to allow sufficient area for trees, food production, composting and for the infiltration of stormwater from roofs.

Car travel

Cars are one of the biggest sources of heavy metal and hydrocarbon (e.g. oil, diesel, petrol) pollution in the urban environment. Heavy metals are released from the wearing down of break pads and tyres. Hydrocarbons are released from cars during normal operation, when cars are washed or servicing, and when there are accidents. In 2020 more than 1000 litres of diesel fuel was spilt in Doreen in a new housing estate and the diesel entered the Plenty river via stormwater pipes. At Botanica Park the sediment in the lake was found to have up to 800 mg/kg of hydrocarbon pollution (Victorian EPA category D classification).

Bikes, public transport, telecommuting and car share arrangements dramatically reduce the number of vehicles using the road and will therefore reduce stormwater pollution. Even though electric cars are marketed as being zero emission they still use conventional car tyres and brakes (although reliance on braking is less due to regenerative braking).

Compost all food and garden waste and avoid fertilisers

Fertilisers applied to lawns and gardens wash into waterways resulting in the growth of algae, Azolla and bacteria. The scientific term for this is eutrophication which is the excessive addition of nutrients in a waterbody, which causes a dense growth of plant life. A large growth of algae can reduce dissolved oxygen in the water causing fish to die (i.e. fish kill or black water events). When Azolla die their decomposition can also reduce dissolved oxygen in the water column.

The solution is to stop all chemical and store bought fertiliser additions to your garden (including manures). As an alternative input you can:

Compost all green waste from plants on your property.
Dilute urine (1 in 10) and use as a liquid fertiliser.
Make compost teas using Comfrey and worm castings and use as a liquid fertiliser.
Use crop rotation techniques to help replenish soil nutrients.
Use nitrogen fixing cover crops to add nitrogen to the soil.
Add humanure to garden beds and fruit trees.

You can watch the Netflix documentary - Breaking Boundaries - The Science of our Planet narrated by David Attenborough and Johan Rockström to see how high levels of nutrients can lead to the collapse of fish species in waterways. Nutrients mainly end up in waterways from the excessive use of synthetic fertilisers in agriculture.

Produce less wastewater and sewage water

Have you ever wondered what happens to the water you flush down the drain?

Well the waste water in our local area is piped and pumped to sewage treatment plants via an elaborate connection of pipes called the sewerage system. Our poo and wee are digested by bacteria to break down organic solids and other hard rubbish is filtered out. Some of this water is recycled and sent back to homes for reuse for toilet flushing, the laundry or the garden. But most of the excess water is released into our local waterways because it is cheap and easy to do this. However this is terrible for the aquatic wildlife.

I don't feel bad or embarrassed about talking about poo and wee because I have Clover and Muffin as my role models. They are my two pet rabbits. Every day I clean out the litter (poo, wee, sawdust and straw) and I put it in large wire constructed compost bays. I water the bays with tank water (no chlorine in the water) and eventually after 6-12 months I put this composted material back on my garden.

Clover and Muffin are not connected to the sewerage system (i.e. pipes that take waste away). They do not take lengthy showers (rabbits groom themselves). The water they use is in their drinking bowl and embodied in the food they eat. About 95% of the water they use has been used to grow the food they eat (so called - invisible water because you don't see it directly). Grass grows well with only rain water. Vegetables such as kale, spinach, herbs, parsley, coriander, carrots, beetroot tops, nasturtiums, etc - all require regular watering. Perennial food plants that they love to eat such as apple, persimmon, grape and fig require less watering because their roots can penetrate deeper into the ground to take advantage of ground water and stores of soil moisture.

The concept of using drinking water to flush away human wastes is becoming very dated. It is probably a good time to change our habits. Today many people also flush hazardous chemicals down into the sewers. Most of these chemicals will eventually end up in waterways and the ocean.

Many experts including the Victorian EPA are saying that we should try to use waterless composting toilets. If we set up our houses with rainwater tanks, grey water recycling systems and waterless composting toilets we could reduce our tap water (potable water) use by 70% and disconnect from the polluting sewage treatment system.

Happen Films have created a short video on how to make your own composting toilet. The video is titled Closing the Loop because a composting toilet is a great way to recycle nutrients back into the garden. Click on the link to watch the video - Closing the Loop - Composting toilet

Swedish people and the Americans have been pioneers in the use of waterless toilets. You can legally buy them. For a complete list visit this link compiled by the Victorian EPA Waterless Composting Toilets Victorian EPA

If you would like to know more about what scientists think is best to save our cities from future drought by installing rainwater tanks, grey water systems and waterless toilets look at this report from the Australian National University (ANU) - | Troubled Waters - Confronting the Water Crisis in Australia's Cities - Conclusion - Making the transition to sustainability

Climate Change Mitigation

Long term we also need to dramatically reduce Green House Gas (GHG) emissions to stop the warming of the planet. Scientists are telling us that by 2030 each person should be aiming for 1-2 tonnes of GHG emissions per person to keep global warming to less than 1.5degC. Some suggestions to help us achieve this goal are listed below.

GHG emission from food

The Victoria EPA determined that food makes up around 30% of our personal eco-footprint. This is more that our contribution from transport and home energy use. City of Melbourne - We need to talk about food.

The solution is to grow more food at home and compost all food and garden waste at home. Turning all your cuttings and green waste into organic mulch will lock more carbon away in soils as humus and fertilise the soil. Each household can also produce humanure to use under fruit and nut trees.

GHG emissions from transport

Twenty percent of all GHG emissions in Australia are related to transport. The solutions are varied:

Ride your bike, take public transport or work from home (telecommute).
Avoid using the car or use a car share service.
Electric car manufacturers claim that their vehicles are zero emission, however, their production releases 15 tonnes of GHG emissions.
The tyres, brake pads, roads and overall costs associated with their maintenance all contribute to significant GHG emissions.
Charging a car will still draw heavily on coal and gas powered electricity plants.

GHG emissions from house construction

The construction of a new house releases the equivalent of 90 tonnes of GHG emissions. This figure does not include the GHG emissions for the production of roads, utility supplies, fast internet, waste management, etc.

When you do buy or build your own home, build tiny.
Moving to the larger towns in the country is more sustainable than adding to the urban sprawl in Australia's biggest cities.

GHG emission from homes

Homes contribute at least another 20%-30% of per capita GHG emissions. This is largely due to the energy sources that are used in home (electricity, gas) and waste products produced by homes (sewerage and food waste). There are many simple steps you can take to reduce GHG emissions from your home.

Switch to green electricity and green gas.
In winter - Heat small spaces in winter, rather than the whole house. Dress warmly and keep active in winter. Invest in insulation and make your house more air tight. Turn your house into a Passive House. Check out this video - Passive House explained in 90 seconds
In summer - Shade the house with deciduous trees and vines, especially on northern and western walls. Water your garden well with tank water to help trees and plant transpire (the plant equivalent to perspire). Use fans to keep cool rather than air conditioners.
Reduce energy consumption at the home (yes - even if you are using green energy it is still necessary to economise on energy consumption). The average Victorian home uses 15kWh of electricity per day. Some energy efficient houses use only 1-5kWh per day.
Install a solar hot water system. Water can be heated very efficiently using the sun.
Install a modest solar PV system (e.g. 400 W to 1.5 kW) and invest in a community battery storage scheme.
Take cooler and shorter showers. The less water you need to heat, the lower the GHG footprint. Two minute showers at 25degC is a good target.
Consume less. Everything we buy requires energy inputs and most energy is from the burning of fossil fuels. This is the embodied (invisible) energy in things. Buying less and buying from thrift stores will contribute to a lower GHG footprint.
Watch this short video (15 minutes) filmed by Happen Films that shows how you can live more sustainably at home. Happen Films - Sustainable living in Melbourne City

Smart Cities - How to protect the Platypus?

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