Return to Katherine Start Page
|March 2007 Katherine River stats|
OK it is March 2007 & we have water issues around Darwin, Adelaide River township, Jabiru & Oenpelli due to the Tropical Low Pressure bringing in a lot of moisture. Some places up that way had 200+ mm in 24hrs. (290+mm on the Daly River)
The Katherine River had a nice dump way up at its source on the 1st & 2nd March 2007 with 138 mm & 69mm the day before at the upper reaches & not really much much elsewhere (do 40-70mm overnight falls really count up here?)
There is a disturbing figure at the Central Arnhem Plateau of 79mm & 235 mm, however if my theories are correct this weather station is pivotal on the plateau (meaning the rainfall will spread to Katherine River & South Alligator Rivers, so this recording must be taken with a grain of salt, although will play a part in the Katherine River flow)
Lets look at some stats when the Katherine River inundated many homes and crept into the CBD in April 2006 (a write up of this event is written here)
Comparison to April 2006 & March 2007 will cause alarm when we move to the actual "river levels" at various points along the Katherine River. BUT the current situation is VERY different, although will cause concern & the main gateway we need to keep in mind is the NITMILUK CENTRE RECORDINGS as this is the last point before Katherine Township. It must be stressed that no two events will be the same & we have seen this in previous comparisons. ie what is recorded at Nitmiluk one year may not correspond to the height in Katherine at another time due to different rates of flow & other local factors.
FIRST come the relative rainfall stats
|2006 Rainfall Stats||
2007 Rainfall Stats
Rainfall of significance in Region on
04Apr06 that contributed to
The Katherine Flood of 2006
Rainfall figures are all very well & good, however it is the River Levels that people now watch after the rain has fallen.
SECOND, LOOK FOR A RECORDING STATION TO LAY A FOUNDATION OF STATS
I have chosen Birdie Creek as it is the final gateway before entering the Nitmiluk Gorge system (which restricts flow) before the recordings at the Nitmiluk Centre. (See this page for a Satellite visual on the mentioned sites , Birdie Creek, Nitmiluk Centre & Katherine Bridge)
1998 Birdie Creek showing 6.3m
2007 Birdie Creek 5.32m @7AM 03March07
2006 Birdie Creek 5.6m
2007 Birdie Creek 6.59 @ 6PM 06March07
The Chart below is of water height over 10
years at the Birdie Creek recording station
located on Katherine River 90km above Katherine
This image has been updated manually by me (so may be grossly incorrect)
I think I have the 8.74 metre record worked out from the NT Water Resources site, but who knows.
The chart below is the last 7 days water levels at the Birdie Creek recording station to 04March07
Katherine R near Birdie Creek* 5.45pm Sat 6.59 rising minor 03March 07 (official printout) but got a tad higher (6.7ish)a few hours later.
So Already in 2007 the Birdie
Creek water levels are exceeding the 2006 Birdie Creek levels**.
**Now the charts may be out or I may be reading them incorrectly with reference to the max height recorded & the chart itself.
But take note that in 2006 we had much localised rainfall with 95mm pouring off of 17Mile Falls / Creek & feeding the Katherine River as well as local rainfall of 50mm backing up the Katherine River.
In 1998 we had buckets of localised rain that backed the river up.
In March 2007 there is nothing
significant pouring into the Katherine River (below the Gorge) that will back it
In fact the River should be able to spread up the creeks with ease.
THIRD - COMPARE THE RIVER LEVELS & MONITOR THE RATE OF RISE
The Following are the
unchecked Telemetered River level recordings for Nitmiluk & Katherine Bridge.
|27ish hours after the peak at Birdie Creek the
lump of water reaches the Nitmiluk Centre
see in red the peak at Nitmiluk of 4.76 metres early Monday Morning at
The Watch is called when the River at Nitmiluk is at 3
metres. In Town at the time of the "watch" the River was on 8.45metres.
The fastest rate of rise of the river in Katherine Township was just over 4 metres in a 24 hour period (2.25 metres in 12 hours)
The thing that annoyed me is the "official" statements that the "river may rise to 15+ metres within the next 12 hours (which was over double the current rate at the time) (and rate of rise at Nitmiluk was slowing). Katherine Bridge was on 10.61m at the time
"The Katherine Regional Counter Disaster Committee met this evening to assess conditions and at this stage the river could possibly reach 15.5 metres at the Railway Bridge within 12 hours."
More care should be taken next time and a review of the written content of the stages. (maybe it should be mentioned as 24 hours instead of 12 hours which is more realistic) (in this case)
Please note that these recordings will only relate to this volume of water and rainfall conditions for the region. Every situation will be different with different parameters in the future. (however hopefully the above may relate to a future river rise to 13metres)
The following were some historical recordings and may be deleted in due course.
As of 8.10 PM on Saturday
Night 03March07 the official readings at
Nitmiluk are 1.84 & Katherine Bridge are 7.51metres
(in the last 12 hrs the river has risen 1.1metres in Katherine)
Sunday Morning now
04March07, and Katherine Bridge at 8.31M (rising at
approx 8cm per hour)
All going normal as it does.
We will see the rate of rise per hour increase slightly over the coming days
Rate of rise in Nitmiluk is slowly increasing
2.00PM Sunday Arvo 04March07
Current level at Katherine Bridge is 9.43m (Rate of rise over last 3 hours is 50 cm)(20cm for last hour)
At Nitmiluk the level is 3.95m (15cm for last hour)
It's just after 9.00PM
Sunday night 04March07
Category 1 Flood
Advice issued at 10PM on
Police Website 04March07
Monday 05March07 5.30AM
|Good Morning, 6 more hours have passed and the river level at
Nitmiluk has only risen 9 cm to 4.77m.
(so it shouldn't be long before it reaches a peak)
Katherine Bridge level will continue to rise throughout the day.
Katherine river at the bridge rose 1.05metres over the last 6
hours to 12.23m @5AM
So expect a few more metres on the bridge level and many cars crossing the bridge for a look see today.
Wednesday Night 21March07
A Flood watch has been issued as the Nitmiluk
Gauge hits 3Metres and risen an extra metre over the last 2 hours.
This is from the surge of water coming down from rainfall upstream of the Gorge over the last day+.
Nothing unusual about that for this time of year.
The interesting thing is the correlation of stats between this lot of river heights (with localised rainfall, ie 100+mm in Katherine itself)
And earlier this month the rainfall was very much above the Gorge & not in town (so flowed freely through the Gorge & not hindered downstream) .
The Katherine Bridge level is several metres higher at this time (in comparison to recorded levels at Gorge last time) due to local rain.
The local rainfall is already heading downstream, and we have a 12+ hr wait for the Nitmiluk water (plus 17Mile Creek/falls)
& no doubt Maud Creek, and locally tomorrow with Tindal Creek as it affects the town drain.
I don't think anything overly interesting is going to happen as nowhere near the volume is coming from Birdie Creek peak (as of yesterday's data),
but add to that tonights water & it just goes to show the parameters involved and reasoning behind the stages of flood warning categories.
Please be advised that these are just my observations and may
be grossly flawed.
Do not rely on this for future reference.