Page 1 of 2

Pick Your Date!!

Posted: Thu Apr 14, 2011 12:23 pm
by DLRA
Welcome back to that fantastic new game show; "Pick Your Date"
The aim of this post is to come up with the best date for next years event. Based on what ever information you care to offer.

Round 1
Q. When are the New Moons for 2012?
(lowest water table)
A. 23 January, 23 February, 22 March, 21 April, 21 May, 19 June, 19 July, 17 August, 16 September, 15 October, 13 November, 13 December

Q. Month of least rainfall?
(lowest rainfall)
January 14.8, February 19.3, March13.1, April 11.7, May 18.7, June 16.0, July 15.0, August 13.8, September 15.1, October 16.0, November 17.1, December 14.3, Total 184.9

Q. La Niña events are associated with wetter than normal conditions, When did these occur? What was the strength of these events and how did this effect rainfall over these years.
A. See summary below
08/2008-02/2009 Weak / Very Much Below Average
06/2007-02/2008 Moderate / Average
05/1998-03/2001 Moderate / Above Average (2000), Average (1999,2001)
04/1988-07/1989 Moderate to Strong / Highest on Record (1989)
1973-1976 Moderate to strong / Highest on Record (1973,1974,1975,1976)
1970-1972 Moderate / Below Average (1970,1971), Above Average (1972)
1964-1965 Moderate
1954-1957 Moderate
1949-1951 Moderate
1942-1943 Weak
1938-1939 Moderate
1938-1930 Weak to Moderate
1924-1925 Weak
1916-1918 Strong
1909-1911 Moderate to Strong
1906-1907 Weak to Moderate
1903-1904 Moderate

Summary: So what does all this mean, well on average we get an La Niña on average every 6 years. To get 3 so close together has never happened before. We did get one good patch of twelve years between events (76 to 88). Just so you don't have to look it up, the years we did not run were - 1992, 1997, 2007, 2008 and of course 2011.

Moving on to round 2 are the Months of March and April.

Re: Pick Your Date!!

Posted: Thu Apr 14, 2011 2:32 pm
by Lynchy
Greg

Without fail the best conditions are 2 weeks before we all go to the lake. So let's schedule it for then.

Lynchy

Re: Pick Your Date!!

Posted: Thu Apr 14, 2011 4:48 pm
by Norm
Well done Greg for all the research. While stats are great sometimes you need local knowlage as to when the lake is dry. From memeroy wasnt the lake dry over Xmas and speaking with Doc he said that the lake is dry in October -November. (I maybe wrong :oops: ) What has been the condition of the lake at the Xmas working bees over the past say 5 years?

I think we need that info along with the stats to pick a week, but you know what will happen, what ever we pick is subject to Mother Nature.
Some people say its to hot early in the year. The question I have is why not? I know this will create some debat :evil: but I think we need to have that discussion.

Norm

Re: Pick Your Date!!

Posted: Thu Apr 14, 2011 8:35 pm
by REAL Stan
It seams to me the month of February is the best time good hot weather hard salt :D :D :D

Re: Pick Your Date!!

Posted: Thu Apr 14, 2011 9:03 pm
by penny
It seems to me that the ramp issue is by far a large denominator as to wether the event goes ahead !

Re: Pick Your Date!!

Posted: Thu Apr 14, 2011 9:29 pm
by momec3
Heh Greg
Do we win a prize if we guess it right. :lol:

Chris

Re: Pick Your Date!!

Posted: Fri Apr 15, 2011 9:46 am
by Mossy
Here's a bit more info on Pt Augusta averages. April is traditionally the best time of year in this region, least rain, least wind and usually sunny.

Av rainfall mm. Jan -16.9, Feb - 7.8, Mar - 7.9, Apr - 5.7, May - 19.2, June -20.1, July -17.9, Aug - 19.4, Sep- 20.0,
Oct - 17.4, Nov - 13.9, Dec - 7.8.

Av Max temp C Jan - 32, Feb - 31.8, Mar - 29.1, April - 25.1, May - 20.5, June - 17.6, July - 16.9, Aug - 18.4, Sep - 21.5, Oct - 25.1, Nov - 28.2, Dec - 30.1

Cheers Mossy

Re: Pick Your Date!!

Posted: Fri Apr 15, 2011 8:14 pm
by OLDtimer
Mossy is right, April is the best month rainfall wise, but I believe we should stick with March. Pete DLRA #6

Re: Pick Your Date!!

Posted: Fri Apr 15, 2011 9:50 pm
by Greg Watters
April is going to be much shorter days and wet salt in the mornings , and if there was a previous rain event take much longer to dry out as a trade off for potentially still dry autumn days ... dunno, i'm still inclined to think we should stick to our traditional dates or near to , with the weather a chance thing we could easily get 10 dry years :?: :?: :?: :?: :?: or not....

Re: Pick Your Date!!

Posted: Fri Apr 15, 2011 10:08 pm
by Dr Goggles
Greg Watters wrote:April is going to be much shorter days and wet salt in the mornings , and if there was a previous rain event take much longer to dry out as a trade off for potentially still dry autumn days ... dunno, i'm still inclined to think we should stick to our traditional dates or near to , with the weather a chance thing we could easily get 10 dry years :?: :?: :?: :?: :?: or not....
x 2

Re: Pick Your Date!!

Posted: Sat Apr 16, 2011 12:11 am
by OLDtimer
I agree, although April is best rainfall wise etc, we have had a good run over the last 21 years, I really think we should stick with our traditional March dates. This crap weather pattern must revert to how it used to be soon, surely. Pete, DLRA #6.

Re: Pick Your Date!!

Posted: Sat Apr 16, 2011 10:38 am
by Dr Goggles
In 2007 when I spoke to a bunch of people about the issue I didn't find anyone who dismissed the tidal effect of the full moon.I spoke to Harry Duncan a hydro-geologist and mining engineer( since died), his interest was more why I'd think it wouldn't have an effect adding only that it didn't move as fast as the tide.I can't find his name right now but I spent a while talking to the owner of the station that includes Lake Hart( at the northern end of Gairdner)he didn't let me finish the first question before he launched into it. He maintained that "all the dry water holes on this place change color on a full moon" and that " roo-shooters won't go out on the lakes under a full moon because you get bogged"..

The rain figures are historical data and have no bearing on when it will rain but they are are only guidepost as to the likelihood of rain at any given time...........heck, the last twenty years may not conform with the historical data( I haven't looked) and we may have just been dead lucky..........there may be something in looking into storm events, is it more likely to get big dumps, or multiple light falls ?....

For my money we need to stay away from full moons that's at least one factor we can be sure of.

Re: Pick Your Date!!

Posted: Sat Apr 16, 2011 10:54 am
by Greg Watters
we have seen the water movement in the US when the evening tide comes in, pot holes in the main tracks like the road to the pits can be 100-`120mm deep or more and you can see the changes in level of the water just under the surface they can be dry all day and 1/2 full of water by late arvo , can't remember the moon at the time but i think it was getting pretty full , after seeing that quite clearly i have no doubt of the internal tide, how it manifests itself on our thicker salt could be an entirely different matter..

Re: Pick Your Date!!

Posted: Sat Apr 16, 2011 11:00 am
by RGV
Ive just done a search on "full moon effects on water tables" and it seem gardeners know all about this.

A quote from a site that might be interesting.

Water Table
The phases of the moon affect the amount of moisture in the soil. There is less water in the soil during the last quarter of the moon's phase because the water table is at it lowest during that phase. Lunar gardeners turn over their gardens during this time, because less moisture makes the soil easier to till.



Read more: The Effects of the Moon Phases on the World | eHow.com http://www.ehow.com/facts_7282788_effec ... z1JdgTPqpA

We need the "Mythbusters"

Re: Pick Your Date!!

Posted: Sat Apr 16, 2011 12:55 pm
by Dr Goggles
from Wiki:

A playa lake is formed when rain fills a round depression in the landscape, creating a small lake. The water is generally freshwater, When all of the water evaporates, a playa is formed. The playa appears as a flat bed of clay, generally encrusted with precipitated salts. These evaporate minerals are a concentration of weathering products that have been left behind. Some examples of evaporite minerals are sodium carbonate, borax, and other salts. Playas are often found in bajadas, a depositional landform of desert environments.[1]

Dry lakes can also form when the water table intersects the surface and water seeps into them.

Dry lakes are typically formed in semi-arid to arid regions of the world. The largest concentration of dry lakes in the world (nearly 22,000) is in the southern High Plains of Texas and eastern New Mexico.[citation needed]

Most dry lakes are small, however Salar de Uyuni in Bolivia, near Potosí, the largest salt flat in the world is of 4,085 square miles (10,582 square km).

Many dry lakes contain shallow water during the rainy season, especially during wet years. If the layer of water is thin and is moved around the dry lake by wind, an exceedingly hard and smooth surface may develop. Thicker layers of water may result in a "cracked-mud" surface and "teepee" structure desiccation features. Very little water can result in dune formation.




For starters we need to remember that Gairdner has no tributaries it fits the description above of the water table intersecting the surface.This year we were contending with a water table that was already loaded, then we got rainfall , it had no-where to go.

The layers of mud that have been deposited are more the worry. The lake copped a big layer of mud in 07, it needs to be dryish or have a thick layer of salt on top of it.....the muddy parts near the ramp likewise.

I imagine that the salt is much more permeable than the soil but either way the lower the water the table the better when we are lookin for hard salt.

That mud is slowly sinking as the salt is dissolved and then precipitated as the water evaporates each time the lake dries.......if the salt washes off/dissolves, then the water blows up north before it evaporates we're screwed, we need the salt to be deposited at the ramp.