Evaporation

[addy1]

My weather station shows ET which is so far ET this year is 21.86 and rainfall is 20.97 .



Water cycle of the Earth's surface, showing the individual components of transpiration and evaporation that make up evapotranspiration. Other closely related processes shown are runoff and groundwater recharge.
Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves. Evapotranspiration is an important part of the water cycle. An element (such as a tree) that contributes to evapotranspiration can be called an evapotranspirator.[1]

 

[AnthonyRibis]

So if ET is higher than rainfall you will have more evaporation? I have pretty much doubled the amount of plants I had from last year and created more surface area with the new bog.

I guess my major concern is winter time. I run my falls through winter and this year will be the first with the bog. I dont know what to expect and I dont want to have to do many water adds in the dead of winter...

 

[Timothy]

I can only address the second part of your response, but I can share from experience.
During the winter we don't run anything except a surface heater that keeps a small area of pond surface open for gas exchange. We shut down the bog altogether and it froze solid with no ill effects on the plants in the spring and the entire bog is above ground level. (There is a vacuum break in the high point of the bog supply line to prevent the bog from siphoning back to the pond when the pump is stopped.) We do remove the pumps, and any piping that is at the air/water interface to prevent freeze damage. (I just tie a line around the pipe in question and let it sink.) My theory with these two things is the ice and snow that accumulates on the surface prevents any water from evaporating, and the earlier in the season the pond ice is covered in snow the better as it slows the ice thickness forming underneath with the snow acting as an insulator. Last winter the ice formed 14" thick in our 36" deep pond, yet everyone survived with no ill effects. We don't run anything but the heater.

 

[Meyer Jordan]

My weather station shows ET which is so far ET this year is 21.86 and rainfall is 20.97 .



Water cycle of the Earth's surface, showing the individual components of transpiration and evaporation that make up evapotranspiration. Other closely related processes shown are runoff and groundwater recharge.
Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves. Evapotranspiration is an important part of the water cycle. An element (such as a tree) that contributes to evapotranspiration can be called an evapotranspirator.[1]

Without knowing the exact coverage in sq/ft and what species of plants are involved and what percentage of the total sq/ft that each specie covers, there is no way to determine an accurate evapotranspiration rate as each plant transpires differently.
A calculated ET rate is typically lower than the prevailing Pan evaporation rate as the plants provide shade which reduces the evaporation portion of the ET.

 

[Dave 54]

So if ET is higher than rainfall you will have more evaporation? I have pretty much doubled the amount of plants I had from last year and created more surface area with the new bog.

I guess my major concern is winter time. I run my falls through winter and this year will be the first with the bog. I dont know what to expect and I dont want to have to do many water adds in the dead of winter...

One should not run your walls throughout the winter lest you super chill the pond , as to evaporation it is our lot during the summer all you can do is top the pond up from time to time .


Dave

 

[Shdwdrgn]

@Timothy -- regarding your "well-seasoned" roof, that is definitely not an indicator. When I rebuilt my pond in 2011, I too thought to collect rainwater to refill the pond, and buried a 2" pipe leading from the downspout to the pond. I had an early rain while still working on construction and came out to find an oil slick on the surface of the water! At that point my roof was approximately 41 years old (I was told it was the original shingles when I replaced my roof last year), so it certainly had plenty of time to leach out any residual oils, but the results spoke volumes and I immediately ripped up the plumbing and scrapped that idea. Glad it works for you, but an old roof can't automatically be considered 'safe'.

@Dave -- I've been running my pumps and falls year-round since 2008, I find the circulation actually prevents the ice from getting as thick, and when the pond is frozen over the water temp still rises quite a bit despite a shell of ice that the falls are flowing through. If I shut off my pumps through the Winter, the ice would get significantly deeper and the stream would freeze up solid.

 

[Timothy]

@Timothy -- ............ I had an early rain while still working on construction and came out to find an oil slick on the surface of the water! At that point my roof was approximately 41 years old (I was told it was the original shingles when I replaced my roof last year), so it certainly had plenty of time to leach out any residual oils, but the results spoke volumes and I immediately ripped up the plumbing and scrapped that idea. Glad it works for you, but an old roof can't automatically be considered 'safe'.

I agree, nothing that works for one can be absolutely certain to work for another. I was relating my experience and would expect anyone to experiment with their system and not take mine or anyone's word as gospel without first testing it in their environment.. Had that been my project I might have just diverted the water to another area for a while and not been too hasty about abandoning the project before I discovered the source of the oil. It may have been release agent from the piping, or any number of temporary phenomenon that might have resolved itself in just a couple of rain storms. I'm sorry it didn't work for you, but being on a well, it's been a real help to us.

 

[addy1]

Without knowing the exact coverage in sq/ft and what species of plants are involved and what percentage of the total sq/ft that each specie covers, there is no way to determine an accurate evapotranspiration rate as each plant transpires differently.
A calculated ET rate is typically lower than the prevailing Pan evaporation rate as the plants provide shade which reduces the evaporation portion of the ET.

true true, it is just a little bit of new data my weather station feeds me.
I do know during summer the pond does drop every day once the bogs plants get going good. I just adjust up the time on the auto water timer so it stays full. Right now it is up to 40 minutes every day.

 

[addy1]

When I rebuilt my pond in 2011, I too thought to collect rainwater to refill the pond, and buried a 2" pipe leading from the downspout to the pond. I had an early rain while still working on construction and came out to find an oil slick on the surface of the water!

I started using our roof water as soon as we had the pond built, (on a well) never saw any oil slick. Our roof was one year old at the time, shingles, the other is metal.

 

[AnthonyRibis]

One should not run your walls throughout the winter lest you super chill the pond , as to evaporation it is our lot during the summer all you can do is top the pond up from time to time.
Dave

I have been running my falls through winter since I started. It doesnt fall directly in the deeper part of the pond and its drawing water from my skimmer. So its not disturbing the water on the very bottom.

 

[AnthonyRibis]

true true, it is just a little bit of new data my weather station feeds me.
I do know during summer the pond does drop every day once the bogs plants get going good. I just adjust up the time on the auto water timer so it stays full. Right now it is up to 40 minutes every day.

What are you using for an auto water timer?

 

[Timothy]

Just thought I'd share this image from the other day and the amazing amount of water the bog plants are capable of exuding to the atmosphere.

This wasn't morning dew, this was coming from within the leaves.

 

[Dave 54]

I have been running my falls through winter since I started. It doesnt fall directly in the deeper part of the pond and its drawing water from my skimmer. So its not disturbing the water on the very bottom.

Our Pond works in much the same way as yours except ours goes through to the first of four filters I dont know how you have your skimmer hooked into your own system , all I do is reduce the flow of air to the pond for the duration of the winter whilst the pond is covered against the elements

Dave