A little waterway, which became known as the Tank Stream is of great historical significance to Sydney. But Sydneysiders wander the city streets, mostly oblivious that it runs beneath their feet. So here’s a short thread to help you know. The Gadigal People are Indigenous inhabitants of the southern side of Sydney Harbour and relied on this waterway as one of several freshwater sources, for thousands of years. It was a stream of barely 2km, flowing from a swampy area immediately east of Hyde Park to Circular Quay.

In 19C Sydney, piped drinking water was unreliable and mostly restricted to the wealthy. Drinking fountains in public thoroughfares & parks were common. I've been observing some of these old drinking fountains still surving around inner-Sydney. So a thread on some of the best.🧵 St Jude’s Fountain on Alison Road, Randwick was built to be supplied by a natural spring beneath. Four hundred children from the nearby Destitute Children's Asylum watched Mayor John Dawson break a bottle of water over the fountain and dedicate its use to the public in 1866.

When Sydney Desalination Plant was first constructed (2007-2010), it was sized to produce 250 ML/day water. But NSW Gov had the foresight to plan for a future expansion to 500 ML/day. I visited today, to learn how that expansion to might proceed, when the need arises. Thread 🧵 Most importantly, the seawater intake pipe and the concentrate disposal pipe are already appropriately sized for the full 500 ML/day capacity. The site on which the plant (“Stage 1”) is constructed, also has plenty of extra space available for the expansion (“Stage 2”).

I have seen some people question whether we can really introduce flood mitigation capacity to Warragamba Dam without having to raise the wall. Let me explain how we can do that by introducing more “rainfall independent supplies” (RFIS) to Sydney’s overall water supply. (1/6) 🧵 The draft Greater Sydney Water Strategy highlights Sydney’s high rainfall dependence and the need to reduce it by adding new RFIS. This is because our existing supplies are not sufficiently resilient to drought, whereas a higher proportion of RFIS will provide greater resilience.

Lying awake at night, I read this tweet by @TonyHWindsor, encouraging someone to “learn what our Constitution says and how Governments are formed”. As a citizen of Australia, I suffered sudden shame of never having done that myself. So I did and here's an #auspolVote2022 thread🧵

https://twitter.com/TonyHWindsor/status/1520273822137880576

The context here is the upcoming Australian election and the participation of high-profile Independent candidates, not associated with a political party. That’s not new; there were Independents elected to the House of Reps in the first parliament of 1901. en.wikipedia.org/wiki/1901_Aust…

Woah. Great call! Water is Australia’s most valuable resource and we have a long way to go to improve our management of it. A new National Water Commission is an essential step toward such improvement. Great news @terrimbutler.

https://twitter.com/AlboMP/status/1512180545849262082

Is it too early to start listing the things a National Water Commission should address?

I’ll start with:

Wastewater-based epidemiology (“sewage testing”) for SARS-CoV-2 is exciting and some of the best work in the world is coming from Australia. But it's important to communicate accurate conclusions from the science (1/8). abc.net.au/news/2020-12-1… This story, like many others before it, claims breathlessly that this study “shows wastewater testing can detect coronavirus weeks before people show symptoms”. It really does not do that (2/8).

I’ve been reading a lot of commentary about the so-called ‘resurrection’ of the ‘Bradfield Scheme’ today. Here are a few thoughts on the matter from me (thread 🧵...) In terms of our ability to improve and maintain quality of life in Australia, water management is at the very top of the list of areas in which we can have a significant and relatively short-term positive impact. So ALL proposals put forward should be given serious consideration.

COVID-19 has brought with it some discussion of chlorine disinfection practices for drinking water, swimming pools and surfaces. So…I’m going to take the opportunity for a slightly academic twitter thread! 1/20 You probably know that chlorine, in various forms, inactivates (or “kills”) many types of viruses and bacteria. That’s the main reason why we add it to drinking water and swimming pools, and use it to disinfect surfaces in homes, public places and hospitals. 2/20

People have asked me about risks of transmission of COVID-19 via water. I’ve been reading up and this morning, I watched a US-based webcast giving a research update on this topic. Here are a few key points that I can share. 1/20 First, I must point out that I am not a virologist, or even a microbiologist. My field is water quality engineering with a focus on chemical contaminants. So I’m describing only what I’ve learnt from the expertise of others (some shown here). 2/20

In the midst of devastating fires across Australia, rainfall is desperately needed. However, following fires, contaminated runoff to waterways will present a new wave of challenges regarding risks to drinking water quality. I prepared this thread to highlight the key issues. 1/20 When forests burn, they produce large masses of burnt wood and ash, which accumulate on the forest floor. A large rainfall event, when it comes, will wash much of the ash into waterways. In turn, drinking water reservoirs (“dams”) will be impacted by ash and sediment. 2/20

With drought, fires & warm weather impacting so many Australian drinking water catchments, much interest has turned to potential blooms of algae and cyanobacteria in drinking water supplies. So here I present an overview of the key issues (thanks @Gergyl for suggesting it). 1/21 Until 1974, they were called “blue-green algae”, but cyanobacteria are very different organisms to algae, separated by millions of years of evolution. Cyanobacteria are prokaryotes (their cells do not contain a nucleus) and algae are eukaryotes (cells do contain a nucleus). 2/21

Which places around the world are successful examples of drinking water recycling? If you want to know the answer, this thread is for you. It includes examples of groundwater replenishment, surface water augmentation and what is known as 'direct potable reuse' (DPR). Cities that rely on groundwater for drinking water can find that aquifers become depleted when the rate of use is greater than the natural rate of recharge. Groundwater replenishment is the practice of purposefully recharging the aquifer and this can be done with recycled water.

Have you ever wondered what these little "H", "HP", "HR" and "SV" signs, nailed or adhered to NSW telegraph poles or streetsign poles, mean? If so, read on... All of the signs with a "H" are markers for the location of a subsurface fire hydrant. The "P" indicates that the hydrant is under the "pathway" and the "R" indicates that it's under the "road". The green colour indicates that the hydrant is on the opposite side of the road.