Wow! Thanks for posting those pics. I drive over that road fairly regularly and I often wondered what it looked like during the flood. Heres a link to google maps so people can see what its like when its dry

http://maps.google.com.au/maps?q=Harlin,...,57.15,,0,16.99

By crikey, that is a whole lot of water, Adam's link sure puts it into perspective! I would have been nervous just being on the bridge lol!

Great shots... it really shows the phenomenal amount of water. While we're at it... check this street view image near Fernvale where the Brisbane River crosses (below Wivenhoe). I was there a few weeks after the flood and saw debris on those powerlines...

http://g.co/maps/kr7hs

thanks for the pics - especially to coxy of jindalee. I used to work at the real estate that was on the corner - it always concerned me that that area had so many houses in what is a flood prone spot.

Well at least the real estate agent got karma for leasing so many flood prone houses. It's shut down now.

Most businesses there are back up and running.

Thanks Raingauge for the pics and Adam for the "dry" reference point. Have driven over that bridge a long time ago and had forgotten that it's quite a canyon at that spot. To be full to the brim must have been something to behold. Just bear with me while I indulge my nerdy side. It would be interesting to know how that level at Harlin compared to past big floods eg. 1974, 1999. Perhaps you know Raingauge. There are some levels and comparisons made with previous floods in the table in this BOM brochure
http://www.bom.gov.au/hydro/flood/qld/br...enhoe_dam.shtml

Unfortunately, the records are incomplete and Harlin doesn't appear in the lineup. However, given that the levels both upstream at Devon Hills and downstream at Gregors creek appear to have been higher than both 1974 and 1999 and that there was a massive flood in 2011 in Emu creek it appears likely that last year's flood was the biggest flood at Harlin since 1893.

Met an old cow cocky whose property is on Emu Creek. He said that the 2011 flood was in a different league altogether to 1974 and 1999, at his place. He said it was "30 feet above the normal level of the creek". If you look at the records provided, the odd one out is the massive flood upstream at Linville in March 1955. This appears from available rainfall data to have been a fairly localised flood mostly from rain in the eastern half of the catchment upstream of Linville. If you look at the rainfall records of the event here

http://www.australianweathernews.com/data/archive/40/1955_03.HTM

Yarraman has only 150mm over 2 days, but in the east Jimna has more than 300mm, 250mm of which fell in one day. You'd have to wonder about the accuracy of that flood height, except that on the other side of the range at Imbil on Yabba Ck in the upper Mary catchment they also had a massive flood, 1m higher than any other on record, although no figure is available for 1893. Anyway, I'm probably boring you all by now.

By the way, I'd love to see this thread become a repository for people's amazing personal photos/videos of the event like those posted by raingauge. It certainly gives a different perspective to the things. If anybody needs some guidance about how to post pics see Michael Bath's post here http://forum.weatherzone.com.au/ubbthrea...ages#Post802336

Personally, while it looks great I find the whole thumbnails thing a bit fiddly so I just make the images small using this tool http://imageresizer.codeplex.com/
After installation, you just right click on the pic and click "resize pictures" and then “Large (fits a 1920x1080 screen)”. It reduces a 3-4 Meg pic down to about 200kb and drops the new file back in the folder next to the old one. Then you can just upload to Photobucket or the like and direct link the pic into your post by putting an [img] in front of the link address and an [/img] at the end. As long as you keep it to just 2-3 pics of this size per post the mods will be happy (tell me if I’m wrong mods). As I say, I’d love to see more like those already posted.

I’ll put my money where my mouth is and post a couple of my own. The first 2 are pics actually taken on the 27th Dec 2010, the first from the hill in Boonah looking down toward the Dugandan flats and the famous pub. Note the very drowned brand new 4WD in the 2nd pic.




Again on the 27th Dec this next pic was taken by friends from the other side of the Warrill creek flats 1.5 km away looking back toward our house (on the left). Virtually the whole valley was under water. The flood on the 11th Jan was significantly higher.


Finally, for reference, here is a pic of Pennells Crossing just 100m from our house during a 'normal' flood event followed by a video of the crossing on the evening of 11th Jan. Again it peaked later after dark when the Moogerah dam outflow reached us. The noise in our house was phenomenal. Like living at the beach on a rough night.


Here's the Youtube link

http://www.youtube.com/watch?v=tN-QN1-douw&feature=youtu.be

Unfortunately I don't know how Harlin faired in previous floods (we have only lived here 3 years) but I do know that alot of the locals have told me they've never seen anything like it in the many many years most of them have lived here. Our property backs onto Emu creek and it sure was one heck of a flood....here's a few pics of that...

This is looking out the back of our house where you can see the water in the front ditch - that is normally completely dry and then on the left side of the picture is the creek (usually quite a big gully - it's up at least 4 meters here) and running through the centre of this picture you can actually see the water in the Brisbane river! This was just the beginning

An hour or so later...

And just as it starts to come down again (at it's full height it was about 2 feet higher than this. (yes that is our house - thankfully not too much damage just ALOT of mud!)


We would like to not have to repeat this experience!

I should also mention that Emu Creek (and the Brisbane river) flooded twice - first on the night of Sunday 9th and then the morning of Tuesday the 11th. Not sure why? The second flood was 1cm higher than the first flood.

They were the two 1974-like rain events. That is, we had twice the amount of rain in 1974 in 2011's flood. Combined, they caused the area downstream of Brisbane to flood big time.

Or at least that's what I believe. The rain on Sunday the 9th was from Sunday's rainfall and the rain on Tuesday the 11th was probably mainly from Monday's rainfall.

I was bored today and did some "what ifs" in Excel. I get that if the gates were opened at the same rate from 12pm Thu 6/1/2011, pause to reach 67.5m, 67.75, 68m, 68.5m then 68.5m is only attained 5pm Sun 9/1/2011, 74m attained almost 2 hours later than in the actual event and a slightly lower peak release, with a slightly shorter duration of releases above 6000cumecs. Thanks to releasing around 50GL extra over the weekend. I think these advantages are worthwhile.

I'd also imagine that hitting 74m later would increase the likelihood of seeking approval to hold increases when the rain stopped falling and inflows were decreasing.

Other possibilities:
(1) The futile effort to hold Moggill to 3500cumecs may have lasted longer and this may have removed the gains from the above.
(2) Lower Wivenhoe levels may have required continued releases from Somerset. But given that it was well above the target line at the peak, this seems unlikely.
(3) Hitting 74m later might not have delayed W4 as it largely kicked in on a shift change

I challenge the suggestion that this was a poorly researched article.

Do you want to outline exactly what you would have released and when, what the impacts would have been from those releases, upon what grounds you would have made the releases at given times, and what possible outcomes may have a risen if the spatial rainfall distribution occurred in a different manner.

None of this was covered in anything Hedley Thomas reported nor is it contained in your post.

I repeat. Hedley Thomas is a political hack and his article was very poorly researched.

LONG POST WARNING

I did state what I meant generally, but since you are asking for specifics, here we go:

Date Time Actual_Lake_Level Actual_ML_in_dam Actual_release_rate_m3/s Actual_ML_in_dam proposed_release_rate_m3/s Proposed_approx_lake_level
6/01/2011 9:00 67.32 1200019 0
6/01/2011 10:00 67.33 1201119 0
6/01/2011 11:00 67.34 1202219 0 1202219
6/01/2011 12:00 67.34 1202219 0 1202219 51
6/01/2011 13:00 67.35 1203319 0 1203268.6 103
6/01/2011 14:00 67.36 1204418 0 1204130 103
6/01/2011 15:00 67.36 1204418 0 1203892.4 103
6/01/2011 16:00 67.37 1205518 0 1204754.8 103
6/01/2011 17:00 67.39 1207718 0 1206717.2 103
6/01/2011 18:00 67.4 1208817 0 1207578.6 103
6/01/2011 19:00 67.41 1209917 0 1208441 103
6/01/2011 20:00 67.42 1211017 0 1209303.4 103
6/01/2011 21:00 67.43 1212117 0 1210165.8 103
6/01/2011 22:00 67.44 1213216 0 1211027.2 103
6/01/2011 23:00 67.45 1214316 0 1211889.6 103
7/01/2011 0:00 67.46 1215416 0 1212752 103
7/01/2011 1:00 67.49 1218715 0 1215813.4 103
7/01/2011 2:00 67.52 1222047 0 1218907.8 103 67.5m
7/01/2011 3:00 67.54 1224279 0 1220902.2 154
7/01/2011 4:00 67.57 1227627 0 1223829 205
7/01/2011 5:00 67.6 1230975 0 1226572.2 255
7/01/2011 6:00 67.64 1235438 0 1230250.4 303
7/01/2011 7:00 67.68 1239902 0 1233756.8 303
7/01/2011 8:00 67.71 1243250 0 1236147.2 303
7/01/2011 9:00 67.75 1247714 0 1239653.6 303
7/01/2011 10:00 67.78 1251110 0 1242092 303
7/01/2011 11:00 67.81 1254506 0 1244530.4 303
7/01/2011 12:00 67.88 1262429 0 1251495.8 303 67.75m
7/01/2011 13:00 67.94 1269221 0 1257330.2 351
7/01/2011 14:00 67.99 1274881 0 1261859.8 403
7/01/2011 15:00 68.03 1279457 51 1264985 456
7/01/2011 16:00 68.06 1282901 103 1266971 456
7/01/2011 17:00 68.09 1286345 154 1269144.2 456
7/01/2011 18:00 68.12 1289789 205 1271501 456
7/01/2011 19:00 68.17 1295530 255 1276338.4 456 68m
7/01/2011 20:00 68.19 1297826 303 1277910.8 509
7/01/2011 21:00 68.22 1301270 351 1280613.2 561
7/01/2011 22:00 68.26 1305878 403 1284465.2 614
7/01/2011 23:00 68.28 1308206 456 1286033.6 667
8/01/2011 0:00 68.32 1312862 509 1289930 719
8/01/2011 1:00 68.34 1315190 561 1291502 773
8/01/2011 2:00 68.35 1316354 614 1291902.8 825
8/01/2011 3:00 68.41 1323339 667 1298128.2 879
8/01/2011 4:00 68.41 1323339 719 1297365 927
8/01/2011 5:00 68.45 1327995 773 1301272.2 980
8/01/2011 6:00 68.46 1329159 825 1301691 1031
8/01/2011 7:00 68.48 1331487 879 1303277.4 1085
8/01/2011 8:00 68.52 1336176 927 1307224.8 1138 68.25m
8/01/2011 9:00 68.55 1339718 980 1310007.2 1189
8/01/2011 10:00 68.56 1340899 1031 1310435.8 1239
8/01/2011 11:00 68.59 1344441 1085 1313229 1240
8/01/2011 12:00 68.6 1345622 1138 1313852 1241
8/01/2011 13:00 68.61 1346802 1189 1314661.2 1242
8/01/2011 14:00 68.61 1346802 1239 1314470.4 1242
8/01/2011 15:00 68.63 1349164 1240 1316821.6 1242
8/01/2011 16:00 68.64 1350345 1241 1317995.4 1242
8/01/2011 17:00 68.65 1351525 1242 1319171.8 1242
8/01/2011 18:00 68.65 1351525 1242 1319171.8 1242
8/01/2011 19:00 68.65 1351525 1242 1319171.8 1242
8/01/2011 20:00 68.65 1351525 1242 1319171.8 1241
8/01/2011 21:00 68.65 1351525 1242 1319175.4 1240
8/01/2011 22:00 68.65 1351525 1242 1319182.6 1286
8/01/2011 23:00 68.65 1351525 1242 1319024.2 1285
9/01/2011 0:00 68.64 1350345 1241 1317689.4 1285
9/01/2011 1:00 68.63 1349164 1240 1316350 1336
9/01/2011 2:00 68.62 1347983 1286 1314823.4 1335
9/01/2011 3:00 68.61 1346802 1285 1313466 1334
9/01/2011 4:00 68.6 1345622 1285 1312109.6 1334
9/01/2011 5:00 68.6 1345622 1336 1311933.2 1333
9/01/2011 6:00 68.58 1343260 1335 1309582 1332
9/01/2011 7:00 68.57 1342080 1334 1308412.8 1332
9/01/2011 8:00 68.56 1340899 1334 1307239 1334
9/01/2011 9:00 68.55 1339718 1333 1306058 1333
9/01/2011 10:00 68.53 1337357 1332 1303697 1332
9/01/2011 11:00 68.54 1338538 1332 1304878 1332
9/01/2011 12:00 68.54 1338538 1384 1304878 1384
9/01/2011 13:00 68.56 1340899 1385 1307239 1385
9/01/2011 14:00 68.58 1343260 1386 1309600 1386
9/01/2011 15:00 68.61 1346802 1388 1313142 1388
9/01/2011 16:00 68.7 1357429 1394 1323769 1394
9/01/2011 17:00 68.77 1365725 1398 1332065 1398 68.5m
9/01/2011 18:00 68.86 1376494 1404 1342834 1539
9/01/2011 19:00 68.97 1389656 1411 1355510 1605
9/01/2011 20:00 69.1 1405370 1419 1370525.6 1672
9/01/2011 21:00 69.24 1422345 1428 1386589.8 1740
9/01/2011 22:00 69.44 1446897 1440 1410018.6 1806
9/01/2011 23:00 69.6 1466712 1450 1428516 1875
10/01/2011 0:00 69.8 1491685 1462 1451959 1944
10/01/2011 1:00 69.97 1513125 1473 1471663.8 2015
10/01/2011 2:00 70.17 1538617 1539 1495204.6 2031
10/01/2011 3:00 70.36 1563055 1605 1517871.4 2031
10/01/2011 4:00 70.57 1590316 1672 1543598.8 2031
10/01/2011 5:00 70.77 1616520 1740 1568510.4 2031
10/01/2011 6:00 70.96 1641685 1806 1592627.8 2031
10/01/2011 7:00 71.16 1668426 1875 1618558.8 2031
10/01/2011 8:00 71.36 1695406 1944 1644977.2 2031
10/01/2011 9:00 71.56 1722624 2015 1671882 2031
10/01/2011 10:00 71.78 1752854 2031 1702054.4 2031
10/01/2011 11:00 71.95 1776448 2044 1725648.4 2044
10/01/2011 12:00 72.07 1793215 2053 1742415.4 2053
10/01/2011 13:00 72.26 1819906 2067 1769106.4 2067
10/01/2011 14:00 72.41 1841210 2077 1790410.4 2077
10/01/2011 15:00 72.54 1859739 2087 1808939.4 2087
10/01/2011 16:00 72.7 1882728 2155 1831928.4 2155
10/01/2011 17:00 72.84 1902994 2277 1852194.4 2277
10/01/2011 18:00 72.92 1914623 2399 1863823.4 2399
10/01/2011 19:00 72.99 1924798 2517 1873998.4 2517
10/01/2011 20:00 73.06 1935072 2695 1884272.4 2695
10/01/2011 21:00 73.11 1942421 2699 1891621.4 2699
10/01/2011 22:00 73.17 1951241 2705 1900441.4 2705
10/01/2011 23:00 73.22 1958590 2709 1907790.4 2709
11/01/2011 0:00 73.26 1964486 2713 1913686.4 2713
11/01/2011 1:00 73.31 1971917 2717 1921117.4 2713
11/01/2011 2:00 73.35 1977862 2721 1927076.8 2713
11/01/2011 3:00 73.38 1982321 2724 1931564.6 2713
11/01/2011 4:00 73.4 1985294 2726 1934577.2 2713
11/01/2011 5:00 73.46 1994211 2731 1943541 2713
11/01/2011 6:00 73.51 2001658 2736 1951052.8 2713
11/01/2011 7:00 73.61 2016681 2745 1966158.6 2713
11/01/2011 8:00 73.7 2030202 2753 1979794.8 2713
11/01/2011 9:00 73.81 2046825 2991 1996561.8 2713
11/01/2011 10:00 73.95 2068085 3347 2018822.6 2717
11/01/2011 11:00 74.1 2091030 3533 2044035.6 2721 74m
11/01/2011 12:00 74.27 2117163 3667 2073091.8 2991
11/01/2011 13:00 74.39 2135795 4250 2094157.4 3347
11/01/2011 14:00 74.57 2163861 4562 2125474.2 3533
11/01/2011 15:00 74.71 2185835 5167 2151152.6 3667
11/01/2011 16:00 74.81 2201636 5786 2172353.6 4250
11/01/2011 17:00 74.89 2214333 6432 2190580.2 4562
11/01/2011 18:00 74.95 2223855 6774 2206834.2 5167
11/01/2011 19:00 74.97 2227030 7464 2215794.4 5786
11/01/2011 20:00 74.97 2227030 7464 2221835.2 6432
11/01/2011 21:00 74.95 2223855 7458 2222375.4 6774
11/01/2011 22:00 74.95 2223855 7111 2224837.8 6774
11/01/2011 23:00 74.92 2219094 7103 2221290 6774
12/01/2011 0:00 74.91 2217507 6118 2220887.4 6774
12/01/2011 1:00 74.87 2211158 6109 2212176.8 6774
12/01/2011 2:00 74.86 2209571 5492 2208195.8 6432

^---- And you couldn't put that in a table or chart it for what reason?

Not sure how with this forum software.

Does that help? Graphing dam height is too hard to be worthwhile for our purposes, but volume can be done.

Sorry about the X-Axis.

In case anyone is interested and hasn't read it, I recommend section 2.7 of the interim report from the flood commission. It contains an excellent summary of what actually happened.

Nice work Somebody but I'm not sure your timing on implementation of W4 is correct.

My understanding of W4 (which is basically to open gates until inflows are matched) is that it is triggered when dam is likely to exceed 74m based on projected inflow rates from gauges upstream whilst releasing the maximum under strategy w3 (max 4,000m3 at Moggill).

You can see the dam operators implemented W4 at about 8am on 11th whilst the dam level was at 73.7m and the dam inflow was at 8060m3. I would suggest that if they had followed the release strategy you suggest and at 9am the dam was at about 73.5m with inflows over 9000m3 they would have implemented W4 at that point in time (rather than at 11am as you seem to indicate). Even if they waited another hour and implemented at 10am (an hour earlier than your strategy) the result would have been a maximum release rate still very close to what the dam operators actually achieved.

This also only works for this scenario. Different inflow rates might achieve different results keeping in mind when were in 74m+ territory for dam level its most likely a 1 in 50 to 1 in 100 year event.

Irrespective, a 700m3 difference in flow is only likely to equate to 10-15cm difference at the city gauge. And you keep the flow above 6,000m3 for at least 3 hours longer than they actually did which might have implications when combined with increasing flows downstream.

In my mind this does not present a strong case for adopting your strategy.

Indeed the interpretation of the W4 invocation was open to interpretation. This has received the notice of the flood commission, and the new manual requires it to be invoked based on the excluding rainfall forecast. Your point that it might not be invoked later was also my alternate point above (3).

Arguably, it was in breach of the manual not to invoke W4 at 3am Tue 11/1/2011. It is likely fortunate that they didn't do so as the peak release would have been higher if the gates had been opened at the same rate from that point. It will be interesting to see what the final report has to say on this point.


Be that as it may it could never make it worse, except in the sense that Mt Crosby Weir & Fernvale bridges might be closed more often.


Beg to differ. Pretty important if there is 8cm of water in your house, but also what is the difference at Ipswich? Much more significant and likely around 1m (OTOH). Also having the releases occur later allows some more of the naturally occurring peak in the Bremer and Lockyer to pass.

Keeping releases above 6000cumecs longer only occurs if the close down of the releases isn't as rapid. I could have reworked that with a more rapid reduction, but I think it isn't really the point.

And as I have already mentioned, having the outflow peak occurring later increases the prospect of invoking discretionary powers to hold release increases.

Perhaps its more true to say that the old manual contradicted itself re: W4 invocation.

One point has "W4: Wivenhoe storage level predicted to exceed 74m"
A few lines later it has: "This strategy normally comes into effect when the water level in Wivenhoe Dam reaches 74m AHD"

Bolding mine.

Looking at the record it took only 2 hours of 10cm increases in dam level to convince the operators that the dam level was going above 74m. Your scenario has them waiting 5 hours whilst the dam level increases by 10cm, 10cm, 10cm, 15cm then 21cm then they act. I find this highly unlikely.

If they wait til 74m its far more likely that the fuse plug will go. Whilst this will only release another 2000m3 (not sure the exact amount) that makes a big difference at a time when your already releasing 6500-7000m3