Anyone growing anything on their dam to help with evaporation

[RocketOz]

As the title says anyone growing dam covers, I know there are different types and its a personal thing but I know I need something as the sun gets more powerful.
Where you bought your original plant would be helpful and any mistakes or better ways you have learned.
My research has thrown up duckweed anyone know where I could get some

[fishy]

Not an expert by any means just my two bobs worth from what I have noticed. The Thais have their way of doing things so you have to sit back and watch. The dam levels are pretty much controlled by the natural water table and evaporation plays a very little part on the dam levels. It's not even worth mentioning the evaporation effect. Some things happening around the dams at home built two years ago. Water lily's providing natural cover and used in Thai Curries. Also the flowers are pretty! Taking a bit of time but the coconut trees, durian, jack fruit etc around the outside will provide shade over the dam. Bannana growing in the interim until the other trees are established. The trees and vegetation are being established more so to keep the water temperature down rather than evaporation so the fish are happy (more food). There is a plethora of options. This is subsistence living so if  you cannot eat it (or smoke it 555) it will be sprayed with poison. I have noticed if a dam is not holding a reasonable water level they will get an excavator in to dig it deeper and get more flooding (hopefully) from the surrounding water table. I do not know what duck weed is sorry? A big issue with the dams here is the reeds totally chocking it. If the water is deep they cannot survive which is another good reason to dig deep.

[fishy]

A pic of one of the dams being weeded the hard way.

[Tassie]

Water Lily.
Contrary to fishy's remarks "that evaporation plays a very little part in dam levels" I beg to disagree. Evaporation is the process by which water vaporizes and escapes from the water surface, rising into the atmosphere. Thus clouds may form. In many open water lakes and wetlands, evaporation is the major outflow component of the hydrologic cycle. The evaporation from the surface water from dams is enormous.  Tree coverage around the dam prevents wind from reaching the surface thereby reducing evaporation.
In the case of floating-leaved plants (e.g., water lily), most species actually reduce the evaporation loss of water in a lake, when plant leaf coverage is high. Research shows that evaporation losses in lakes and ponds covered with floating-leaved plants are lower than in lakes with no plant coverage. The more floating-leaved plants present, the less evaporation, because there is less exposed water for evaporation.
Regards

[RocketOz]

Thanks guys for your replies.
Yeah I thought of water lilies( she calls them lotus) I will be giving them a try.
Even at this early stage, as the dam is still newish less than a year old, it doesnt have much growing around it yet, but yes banana trees are on the morning sun side, there is measurable water loss to evaporation, thats why Im being pro active and getting a head start.
Will keep updated what I can manage to scrounge, I think I missed out last week as 2 dams nearby were emptied to get the fish, but my mind wasnt thinking water lilies then. Was hoping the farm across the road was going to empty like he did last year and could have asked for the water but unfortunately he is going to do it next year.

[fishy]

Tassie 100% correct with what you say with evaporation and I agree totally. Not enough words in my post to fully explain and I'm good at confusing people.  Our domestic water supply at the Bahn comes from a well which has about 1,000lt capacity. On the occasions it has been sucked dry while the TW is watering the weeds (I have to mow them) and the kids are making mud cakes and I'm half way through having a shave with shampoo stinging my eyes Papa has to jai yen yen and fix the problem. Jokes aside the well fills to the natural water table there is no gully water supply from the slope of the land to the well. In the wet season the well fills to about 1/2 meter from the surface. At the moment it fills to about 3/4 meter. You can watch the water filling it back up.
The dams on the property are the same and the only water capture they get is directly from above when it is raining or from the water table level itself. Just from what I have experienced here.
I'm not trying to knock down evaporation but the natural water table in the local area (Burriram) determines the majority of the water level in the dams. I'm all for shade and doing things naturally when you can.

[Tassie]

fishy, regardless how the water enters the dam, the process of evaporation begins immediately once the surface water is exposed to the atmosphere.  Between the water and the atmosphere there is a thin layer (vapour barrier) of resistance to evaporation.  This vapour barrier is broken when wind flows across the water causing evaporation to increase.  The use of trees as a wind break helps to reduce the breaking of the atmospheric water vapour barrier.  A dense tree cover around the dam wall will provide 18 metre's of still air for every 1 metre in height. Ad water lily's to the equation and you have the most cost effective and natural way to reduce the water loss from evaporation on the dam.
Regards

[fishy]

Tassie 100% agree with your comments. Evaporation can be controlled with natives and doing it right with surrounding vegetation. All I am saying is evaporation of water from dams in Burriram province from my experience is not an issue. The dam will evaporate water for sure... but it will fill up again from the ground water table as quick as it is evaporating. Putting foliage around is a top thing to do but all I am saying is at the end of the day in the Burriram province is if the dam is not holding water and you are concerned about the loss of water by evaporation then there is probably most certainly another reason for the loss which is much bigger than evaporation alone.

[RocketOz]

Sorry but no the dam wont refill from the water table, how can it it isnt to that depth, so it gets lower as you pump some out to water stuff and lowers about the same from evaporation, only reason Im trying to limit evaporation is to see how far I can stretch the dam water till it gets refilled by the rain and we are only half way thru Jan and the big bubny thing will only get stronger.
But thanks for the discussion it all helps.

[urleft]

Why Did L.A. Drop 96 Million "Shade Balls" Into Its Water?

The plastic balls, which can save water and protect water quality, are an attempt to cope with California?s severe drought.

https://news.nationalgeographic.com/2015/08/150812-shade-balls-los-angeles-California-drought-water-environment/

[Smithy]

Why Did L.A. Drop 96 Million "Shade Balls" Into Its Water?

The plastic balls, which can save water and protect water quality, are an attempt to cope with California?s severe drought.

https://news.nationalgeographic.com/2015/08/150812-shade-balls-los-angeles-California-drought-water-environment/

Apparently ...untrue 

 http://grist.org/article/why-shade-balls-arent-such-a-great-idea-after-all/

[RocketOz]

Further to this discussion, after much googling etc. I found duck weed to be best solution, but it will take time to grow enough to cover the dam(I havent been able to find a large source of it in any of the water ways around Lam Plai Mat) it is good as the chooks will eat it, so if it tries to over take the dam can harvest some and feed them.
I did source another plant it spreads a bit faster in the pots we are using to test grow but the chooks wont eat it, may still use it early on and then harvest it to put into compost.
Another plant sourced from the LamPlaiMat reservoir is a honeycomb like plant again chooks dont like it, also a problem with the last 2 maybe they die off and slowly sink and cause problems that way.