Tips for Sydneysiders.

Firefox Extension: Sydney Dams Item

This page shows you how to download the (unofficial) Sydney Dams usage monitor for Firefox. We have seen on the Sydney Dam Statistics Page graphs and analysis of the situation in general in Sydney's dams. This extension shows you how full Sydney's Dams are, continually in your Firefox browser.

If you want to know more about this extension skip down to features or notes and FAQ. If you want to know how to save water, or more about rainwater tanks or irrigation, etcetera, see the links at the bottom.

Here is a screenshot showing the extension in action. The yellow box is the tooltip that is activated by moving the mouse over the spot on the toolbar.

What do I need and how do I install it.
Firstly you need to have Firefox or Mozilla installed (not all features may necessarily work perfectly in Mozilla). Assuming that you already have Firefox installed, the instructions are quite simple.
  • Click a link to download and install the extension.
  • Restart Firefox.
  • Drag the extension's toolbar into one of your Firefox toolbars (e.g. next to the Firefox icon at the top right)
  • Click on it for the first update.
  • Enjoy!
Let us go through these in more detail. (Note that if you are using Mozilla instead of Firefox, you may need to have administration privileges to install this extension)
Download and install the extension.
Simply click here to download it. Firefox will probably complain that you haven't allowed software from my website to be installed on your computer. In that case you need to "Edit Options" (near top right of browser window) to allow this site, then click on that link again to try again. Firefox will ask for a confirmation. It should then download and install all by itself. Then Firefox will ask you to restart itself. You may like to finish reading this document first!.
Restart Firefox.
Exit Firefox fully (File, Quit). Then start it again.
Get the extension onto your toolbar.
The horizontal bars up the top of your browser (e.g. the bar containing File, Edit, etcetera) are called toolbars. What this extension does is to provide a new item that you can put up there on one of your toolbars. To do this:
  • Right-click on an empty part of one of your toolbars (e.g. just to the left of the Firefox symbol at the very top right of your browser, or just to the right of the "Help" menu).
  • Select "Customize". You can now see lots of 'bits' that you can add to your toolbars.
  • At the end (you may need to scroll), you will see Syd Dams Item with some (xx%) etcetera. Drag this whole thing (left mouse button) up to an spot on a toolbar (say to the right of the "Help" menu) and let go.
  • Hit "Done" on the customization window.
    Initialize the extension
    If you are seeing xx% and so on, just click on the xx% and it should update. You should only need to do this once! If you like you can use the preferences to change the frequency of checking for updates. Currently the data is only updated once an hour.
    Watch our dam levels fall RISE!

By default, data will be updated every hour. The SCA data is updated once a week. My estimates in between are based on
A Mittagong personal weather station. Data use is minimal (about 0.05 kb per update or 1kb per day at once per hour) as the data is passed through my server rather than taken directly from the SCA.
The smiling water drops appear whenever it is estimated that the inflow to the dams exceeds the average hourly usage. Additional smiling drops appear when estimates of the weekly, monthly or yearly net effect is positive.
You can click on the extension to update any time, or use the preferences to change the frequency of updates.
This project was heavily based on the NetUsage project by Michael Pemberton and ^critter, and we thank them for showing the way!
Notes and FAQ
  • Currently this extension is only in its very early stages. Expect that the guesses of current dam levels (i.e. between official readings) to often be inaccurate by at least 0.1% (more if it rains).
  • The "Change" column on the tooltip represents weekly change figures, up until the last update time for that data.
  • The percentage figures we give for the SCA data differ slightly from those found on the website as we give our figures to one more decimal place. This means that the "total system" value (available water in the dams) may differ from the figure provided by 0.05%. This also means that the weekly difference may differ by up to 0.1%. We feel that this extra decimal place is justified as the granularity of the SCA figures is 500ML which is about one 4000th of the dam capacity... so the percentages are around +-0.02.
  • In the "My Calculations" section, the figures are given to yet another decimal place. Given the approximation for which the available water in the dams is given (500ML), the direct accuracy of this digit is not high! This digit is merely present to demonstrate the changes in these values from hour to hour (i.e. it is more visible how our dam levels are changing through each hour of the day).
  • The data for "My Calculations" is updated on the server once an hour. Hence, even if you update manually much more frequently, these figures will not change more than once an hour.
  • The figures in "My Calculations" may "jump" each Thursday evening as new, recent reliable data becomes available through the SCA.
  • The "Runout date" given is based on the average change in dam levels over the past year. Hence it will react slowly to changes in water restrictions or a desalination plant. It is designed to give an overall idea of how bad the drought has been for the last year and when the dams will run out if the drought continues as it has.
  • The bar on the left of the tooltip represents the percentage of capacity the dam system is at.
  • The smiley faces represent whether (overall), in the past Hour, Week, Month and Year, the total dam levels have risen or fallen.
  • The hourly change figure represents a guess of the change to our dam levels in the last hour. Note that it assumes that usage is relatively constant through the day.
  • The Inflow/Use value represents the inflow in terms of the current average usage rate. A value of 100% indicates that as much water is flowing in to the dams as is being used. A value of 200% indicates that twice as much water is flowing in as is being used.
  • Inflow/Use corresponds to the percentage of water usage that is currently entering the dams in inflow (approximately).
  • At this stage the hourly figures are very approximate. Similarly the effect of rain (between official SCA readings) is not accurately measured by examining one weather station. In other words, the hourly flow, inflow/use and precise values in general are more guesswork extrapolations than accurate measurements at this stage. These should improve over time as I gather more data.
  • Are there bugs? Of course there are... email webmaster at if you find any!

Sydney dam levels main page
This month dam level statisticsRainfall this week
Trends of Sydney dam levelsUsage and Inflow trends
Firefox Extension (SydDams)Interactive Catchment Map
Dam levels for individual damsSydney Desalination plant impact on dam levels
Reduced Usage impact on dam levelsHow to save water in Sydney
General Information on Warragamba and Sydney's other Dams
Home irrigation/watering systems in Sydney
Old location of Sydney dam levels page
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Email if you need to contact the webmaster.'s subsite on Sydney's water is relevant to people interested in conserving water, rainwater tanks, irrigation, plumbing and plumbers. It can also be of interest to people examining water quality and filtering.