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On a steaming hot day last October we went to see the recently completed Johnston Street Bioretention Basin at Earlwood & go for a walk around Illoura Reserve.
The bioretention basin was much larger & more interesting than I expected. The bush at this location was also a surprise being quite different than other areas of Wolli Creek that I have walked. The trees were gorgeous. Towering Red Gums & Turpentine trees lead into the bush & the dreaded Privet was blooming so the air smelt nice.
We went back again today just to see how much the plants in the basin had grown after all this rain we had. It was as expected, lush & green. What wasn’t expected was all the work done by the volunteers of the Wolli Creek Preservation Society. Signs say they are regenerating the bush around the basin. They had opened up a pathway that allowed us to walk right around the basin & up to the Red Gums. It is so nice being in bushland. That it is so close to Marrickville LGA makes us very lucky in my opinion.
I had not heard of swales & bioretention basins until after starting SoT, so here is a brief rundown of what they do & some stats about this particular basin. A bioretention basin is constructed to manage & clean stormwater before it enters creeks or rivers. Stormwater enters our waterways at a terrific pace. This can erode the bank in places, but also erode the bottom of the watercourse. Stormwater also delivers an enormous amount of pollution to our waterways – nitrogen, phosphorus, heavy metals & fine sediments. All these have a detrimental effect the water quality of our rivers & creeks.
A bioretention basin is really a scooped out landscaped area of land that can be big or small. They generally contain 3 layers: course sand or pea gravel at the bottom, another layer of sand in the middle & sandy loam at the top.
The idea is that stormwater from our streets is directed to the bioretention basin where it literally percolates through these levels. This not only slows the stormwater, but it also cleans it of oils & other substances that comes off our roads. The cleaned water is either allowed to seep naturally into the ground to make its way to the river, or channeled via a pipe or pipes at the lowest layer as it is in this case.
Finally the surface of the basin is planted with native grasses & small shrubs. The plants need to be able to tolerate water as well as periods where the basin is dry. Swales work on the same principle, but rather than a shape of a basin they look similar to a rocky creek bed. The Johnston Street Bioretention Basin also includes a long wide swale running downhill beside the basin. There is a large pipe that directs water from the basin to the bottom of the swale.
The Johnston Street Bioretention Basin, built by Sydney Metropolitan Catchment Management Authority, is expected to remove approximately 2,353 kg of sediment & 13kg of nitrogen annually before it enters Wolli Creek, which flows into the Cooks River & on to Botany Bay. Their sign says that the system is designed to remove 100% of gross pollutants, 79% total suspended solids, 57% total phosphorus & 30% total nitrogen. It’s beautiful & a terrific boon for the environment. It’s also well worth a visit.
I made a short video of the Johnston Street Bioretention Basin & Illoura Reserve here – http://bit.ly/uPLiQX
Today, 22nd March is World Water Day. The UN says the objective of World Water Day 2011 is to “focus international attention on the impact of rapid urban population growth, industrialization & uncertainties caused by climate change, conflicts & natural disasters on urban water systems.”
The theme for 2011 is Water for Cities & “aims to spotlight & encourage governments, organizations, communities & individuals to actively engage in addressing the challenges of urban water management.”
During last Sunday 20th to Monday 21st March parts of Sydney received a record-breaking 6 weeks of rain in just 24 hours with the weather forecasters saying this was related to climate change. The UN says climate change will force more people to live in cities, further stressing the current water management infrastructure.
You only needed to be out on the roads last Sunday to see that many parts of Marrickville LGA were flooded & driving conditions were dangerous. Most stormwater in Marrickville LGA enters the drains until eventually reaching the Cooks River. It’s great Marrickville Council has built a number of bio-swales near the river & set up pollution traps to filter the stormwater as it enters the river. The swales clean up the oils & other ground pollutants collected by stormwater. However, swales are relatively new infrastructure & there is much more work to be done across all the relevant Councils before we can say that the Cooks River is fully protected from stormwater pollutants.
Sydney City Council is planning to capture stormwater from roofs of a large residential area in their Sustainable Street Project. Thousands of litres of stormwater is already being collected in Myrtle Street Chippendale proving that it can be done easily & cheaply. This water is used to water their verge gardens & so far there has not been a need to use water from a private home.
To divert & collect water from roofs is not rocket science so I wonder why we are not all doing it in cities & town across Australia. Marrickville Council has said that many of the new street trees planted die due to lack of water. Very few people want to water the street tree out front because of the added cost to their water bills, yet rainwater from our roofs can be easily diverted to the street tree & verge. Instead, most of the stormwater races past over hard surfaces & the tree gets only as much water as it can grab. If it is a tree in an area that floods, it gets a bigger drink. If not, then it has to learn to survive on very little water or send its roots to where it can access water, often the front garden of the nearest property. This creates problems with some properties & yet it need not happen.
The UN says the following about urban water – “There is growing evidence that water resources will be significantly affected by climate change, both in quantity & quality, particularly through the impact of floods, droughts, or extreme events. The effect of climate change will also mean more complex operations, disrupted services & increased cost for water & wastewater services. In addition, climate change & disasters will result in bigger migration to urban areas, increasing the demands on urban systems.”
Pretty serious stuff, especially for poorer communities in the third world. If climate change does happen in the way scientists expect, then water will become a major issue for us as well & we won’t be happy to see run across our streets, down stormwater drains & into rivers or oceans. Water will be far too precious a commodity for us to allow this to happen.
Farmers in NSW, Victoria & South Australia who rely on water from the Murray-Darling River system have already experienced the environmental destruction, loss of diversity & extreme difficulty growing food while having to buy & get water delivered from elsewhere. I predict that it won’t be too many years before many of us will choose to capture rainwater for our own use because the price of turning on the tap will be prohibitive & Councils will have to address our dying water management infrastructure, again because of costs.
We are the lucky ones with numerous taps inside & outside our homes with hot & cold running clean water. Here are some unnerving stats to finish with –
- Every second the world’s population grows by 2 people.
- 493 million people share their sanitation facilities. This means something like 1 toilet for a street or neighbourhood, not 1 toilet for a household.
- 1.4 billion people do not have access to clean drinking water.
- Every 8 seconds a child dies from drinking dirty water.
- The World Health Organisation says 80% of all sickness & disease worldwide is related to contaminated water.
You can read about World Water Day here – http://www.unwater.org/worldwaterday/
I have written about a way to capture rainwater from your roof to water the verge & street trees here – http://savingourtrees.wordpress.com/capturing-stormwater/
1. In a shocking case of environmental vandalism, the Los Angeles County Department of Public Works chopped down around 250 100-year-old Oak & Sycamore trees across an 11-acre site called the Santa Anita Wash Oak Grove. The trees were razed so they can dump 500,000 cubic yards of silt that they intend to dredge from a nearby reservoir. The community vehemently opposed the destruction of the Santa Anita Wash Oak Grove, but the destruction went ahead as planned & this in a state that prides itself on it’s climate change initiatives. I would have thought that the silt could have been transported to another place to be used rather than destroy a 100-year plus habitat. To see the Santa Anita Wash Oak Grove for yourself, here is a 3.42min YouTube video -http://www.youtube.com/watch?v=bKJ2gEPBEts&feature=player_embedded#! & article - http://www.latimes.com/news/local/la-me-trees-protest-20110113,0,3043421.story
2. We have always known it & now Australian research by Professor Burchett of the University of Technology Sydney has proven it …. pot plants relieve workplace stress. “We found that plants had a very strong wellbeing effect. It was a reduction of a whole lot of negative feelings: anxiety, anger, depression, confusion, fatigue & stress.” Trees are just bigger plants & have much the same benefits. http://www.stuff.co.nz/life-style/3460853
3. In a bold move by the Natural History Museum of Los Angeles, 3.5 acres of carpark will be torn up to create an urban wilderness experience & exhibit. What they intend to create by July 2011 is fabulous. I hope this approach becomes commonplace. http://www.mnn.com/lifestyle/outdoor-activities/blogs/museum-unpaves-parking-lot-to-create-urban-wilderness
4. Glenn Ridge in New Jersey US has established a new Shade Tree Commission that will oversee the health & well-being of publicly-owned shade trees. I have not heard of this type of body before. The Shade Tree Commission will ensue that the care of public trees is open & transparent & will work with the community via outreach & public forums. http://www.northjersey.com/news/opinions/111579264_Keep_us_in_the_shade___and_the_sun.html
5. Polycyclic aromatic hydrocarbons (PAH) are in coal tar which is used to seal roads & carparks. Heavy pollution of US streams, ponds & lakes has been tracked to the use of PAH. Everything we use ends up in our riverways or oceans eventually. It’s time we stopped opting for the quick solution & chose more natural non-polluting products. They are available. http://www.newscientist.com/article/dn19829-organic-pollutants-tracked-down-to-us-parking-lots.html
6. Research by scientists at the National Centre for Atmospheric Research found that deciduous trees absorb about 1/3 more of oxygenated volatile organic compounds & at a faster rate than expected, up to 4 times faster. Oxygenated volatile organic compounds are particularly bad for human health. This is why as many trees as possible need to be planted along our main roads & thoroughfares. http://greenopolis.com/goblog/joe-laur/trees-absorb-more-pollution-previously-thought
7. Scientists from the Swiss Federal Research Institute for Forest, Snow & Landscape in Zurich published research that examined “nearly 9,000 pieces of wood, mostly collected over the past 30 years by archaeologists who use tree rings to establish the age of ancient sites or structures, a technique known as dendrochronology. The result was a continuous – & precisely dated – record of weather in France & Germany going back 2,500 years. The study also showed that climate & catastrophe often line up.” http://news.sciencemag.org/sciencenow/2011/01/fall-of-rome-recorded-in-trees.html?rss=1
8. Green building legislation & initiatives are becoming commonplace in the US with 12 federal agencies & 33 states implementing them despite the recession. In 2008, 156 Councils nationwide had green legislation. By September 2010, 384 Councils have jumped on board. I like this as Australia often follows the US. http://earthandindustry.com/2010/11/despite-recession-u-s-green-building-sector-soars/
9. ExxonMobil, the world’s largest oil company says they expect CO2 emissions to rise
by nearly 25% in the next 20 years, “in effect dismissing hopes that runaway climate change can be arrested & massive loss of life prevented. According to the UK Met Office, if emissions rises can be stopped by 2020 & then be made to reduce by 1-2% a year, the planet could be expected to warm 2.1C to 3.7 C this century, with the rise continuing even higher after 2100.” The Australian Bureau of Metrology said that ocean temperatures around Australia have already warmed by 1.5 degrees. A warmer ocean means greater evaporation, which leads to higher rainfall. This lesson came via ABC TV on the day of the great flood that hit Brisbane & SE Queensland this past week. I think this is a very important article. http://www.guardian.co.uk/environment/2011/jan/19/exxonmobil-carbon-emissions-rise?CMP=twt_gu
10. Every year the city of Paris has 95 collection points across the city where its citizens can take their unwanted live Christmas tree which are mulched to be used in the city’s parks & gardens. “From 15,000 trees recycled in 2007-2008, the number grew to 27,150 in 2009-2010.” Does Marrickville Council have a collection for Christmas trees? If not, it would be easy enough to copy this initiative wouldn’t it? http://www.treehugger.com/files/2010/12/old-christmas-trees-help-other-trees-grow-paris.php
11. Sudden tree death is killing the older trees in the UK. “Already 4 million trees have been felled or marked for destruction.” This is a tragedy. http://www.telegraph.co.uk/earth/8247580/Sudden-death-for-thousands-of-trees.html
12. Friends of the Trees, a volunteer group in Portand have just finished planting their 400,000 tree since the group started 21-years ago. My deepest respect goes to them. http://www.oregonlive.com/environment/index.ssf/2011/01/friends_of_trees_plants_its_40.html
13. In other good news, the Philippines have used Tree Surgeons to successfully heal sick
trees. The emphasis is mine. “Researchers claimed 24 narra trees aged 68 to 73years old were treated after they were on the verge of dying considering that they were described to be landmarks when the construction of the Binga power plant & other facilities commenced in the early 1960s. Seven trees had major treatments using steel bars as mechanical support during the tree surgery while the seventeen others underwent semi-major surgery. Experts claimed tree surgery is the practice of repairing sick & damaged trees to subsequently restore its physical appearance. It is done by removing the injured or deceased parts & treating the same with antiseptics & healing aids & filling the cavities with special materials & cement to fix the surface.” Why does this not happen any more? Or if it does, why do we not hear about it? I know some specialist Arborists look after veteran trees or move trees & care for them like the IKEA Fig, but this kind of work used to be done routinely on suburban trees. Now it seems like if a limb is sick, the whole tree has to come down. http://www.mb.com.ph/articles/292102/tree-surgeries-save-benguets-sick-narra