Tips for Sydneysiders.

Current Dam levels
SourceSCA
Date2012-04-26
% full 96.85
1-week
% change
-0.50
Dams empty date (from 1-year differential)never
Sydney Dam Levels

Current Rainfall and Weather on Warragamba catchment and around Sydney's other catchments and dams.

On this page we bring together current weather and rainfall data that is relevant to Sydney's dam levels. We also estimate how much rainwater is flowing into the dams right now from recent rainfall, giving an estimate of how full Warragamba and Sydney's aother dams are right now. In addition we show how much rain will have what effect on our dam levels. Finally we also give data for those with rainwater tanks, those considering rainwater tanks, grey water use or other methods of saving water.

How much rain has fallen recently on our catchments including Warragamba?
The Sydney Catchment Authority releases information each weekday as to the rainfall on each catchment in the 24 hours to 9am. Unfortunately they are not updating this data on weekends at this stage. The following table shows how much rain has fallen on each catchment area (according to the SCA figures) and gives the catchment area and total rain (in ML) to have fallen on each catchment. Note that a large proportion of this water will be used by people, plants and animals, or will soak into the ground, rather than make it to the dams. Indeed usually only about one seventh (1/7) [my estimate] of the water that falls in the catchments end up in the dams. This also varies between catchment areas (it appears to be lower in the Shoalhaven, for example). Household rainwater tanks do not suffer from this problem as roofs are non-porous.
Catchment Rainfall (mm)
Catchment:WarragambaShoalhavenNepeanWoronoraBlue Mtns
Area km2905058216837522
2012-04-19
2012-04-19
2012-04-20
2012-04-23
2012-04-24
2012-04-26
2012-04-27
Rain Total00000
GL rainfall00000
Days' Supply00000
Note: Rainfall Total is sum of the rainfall in the table. As a guide, Sydney uses around 1.4 GL/day. Days' supply is the number of days of Sydney's water usage that the figures (and estimates of 1/7 of the water reaching the dams and Sydney usage of 1.4 GL/day) represent. Note also that the SCA does also transfer water from dam to dam (in particular from the Shoalhaven System north).
What about the weekends, and what about since 9 a.m. this morning?
Mittagong is fairly close to the center of Sydney's catchments. You can find data from a Mittagong Home Weather Station. You can also see an outline of the Warragamba Catchment on the BOM Sydney Radar display. If you have a high powered computer you can see the history of the Sydney radar over the last few days here. There is a Good map of Sydney's Catchment areas.

The Mittagong Rainfall for the last few days (in mm) is as follows:
Hour:a.m.p.m.
121234567891011121234567891011Total
2012-4-21 - - - - - - - - - - - 0
2012-4-22 - - - - - - - - - - - - - - - - - - - - - - - - 0
2012-4-23 - - - - - - - - - - - - - - - - - - - - - - - - 0
2012-4-24 - - - - - - - - - - - - - - - - - - - - - - - - 0
2012-4-25 - - - - - - - - - - - - - - - - - - - - - - - - 0
2012-4-26 - - - - - - - - - - - - - - - - - - - - - - - - 0
2012-4-27 - - - - - - - - - - - - - - - - - - - - - - - - 0
2012-4-28 - - - - - - - - - - - - - 0

How Full are our dams NOW (2012-04-28 @11:27 )?
Given rainfall (at Mittagong) and usage, my best guess as to the overall dam levels would be 96.727% full. I would also guess that the current total inflow is about 0.0 ML per hour. (note that this figure can be negative if evaporation is large and the rivers are not providing significant water). This figure means that the water flowing into the dams corresponds to about 0 percent of the usage rate and that the net inflow is about -47.7 ML per hour. My estimate of the net change to the dams over the last 7 days is -1.319 percent.

The following graph shows the official SCA data for the overall fullness of Sydney's Dams in dark blue up until the last update (from 2012-04-26 ) in dark blue along with our estimates of this value based on the last official data and the available data on this page. Our guesses will hopefully continue to improve in accuracy over the next few weeks!

More statistics, graphs and trends can be found on the other pages in this site.

External Links
More links on weather and rainfall in Australia...
Beaureu of Meterology
Australia Severe Weather
Weatherzone

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
Back to iliveinsydney.com

Comments by visitors:
by helen @ 30 Jun 2005 03:42 pm
just put a simple page up without all the gaa gaa and say the dam level is ?? and has risen or dropped such and such amount due to the rain.
by Guy @ 30 Jun 2005 05:26 pm
Yeah I just want to know the level. Maybe have a page for the plebs like me who are not scientists and aren't interested in all the other stuff
by Kerry @ 01 Jul 2005 06:01 am
Hey Helen & Guy, if you use the best browser Firefox, install the Firefox extension provided and you have that information on your browser anytime you want it.
These pages are fantastic for when you want more information, or to understand why things are going up or down.
Andrew:Helen and Guy: I hope you like the redesign of the site and the sidebar up the top :). Kerry - thanks!
by Nick @ 04 Jul 2005 06:54 pm
Your estimates of the in flow are falling off too sharply, and were probably too high to begin with. The ratio of rain reaching the dams is also dependent on the amount of rain.
Andrew:Hi Nick. You are right that the estimates for this last rainfall were too high. The main reason for this is that Mittagong (used for this calculation as the figures are updated hourly) received 132mm of rain... whereas the Warragamba and Shoalhaven catchments received more like 70-100mm each. As a result of this, I manually dropped off the inflows very hard to compensate(as you noted well!).
I do keep a model of the dampness of the ground when calculating how much of each hour's rainfall translates into inflow... so far it seems fairly accurate.
What I don't take account of is the overflow when Tallowa spills. The total amount of water falling in the Shoalhaven catchment and Warragamba catchments were very similar this week... yet Warragamba's net increase was triple Tallowa's. Part of this may have to do with Shoalhaven transfers, but unfortunately much was due to the fact that Tallowa hit 100% of capacity. Thanks for your coment, Nick. I can't get away with anything on this site with you around ;)




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I-live-in-sydney.com'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.