Why "no rain contribution" even using "1 m/d" rainfall?

EFDC_Explorer
1

I build a steady state model to learn how EE process the “rainfall”. The model is attached in the attachments. As Fig.a shows, the model has an inflow boundary and a out flow boundary. Their flow vaule is the same. There is a fictitious atmospheric series and a wind series. The rainfall in this atmospheric is 1 m/d. This rainfall is so large that it must make the water level up to approximately 2 m (Initial water level is 1 m).But the water level at Day 5 is still about 1m (Fig.b), not 2m. It implies that the rainfall have no influence. Why does this happen?By the way, why do I must have a “Wind” series if I choose to simulate the temperature? Or it will have an error.
figa.jpg
figb.jpg
fig-no-wind.jpg
no-rain-contribution.zip

2

EFDC will not use the information in the aser.inp file unless at least the temperature module is activated. This means that any rainfall you have in your aser.inp file will not be considered without first activating temperature. In general a wser.inp file with wind speed and direction is also required for the temperature module. The equations that govern temperature in a water body require knowledge of the atmospheric conditions and the wind field in order to work.

3

Hi Tom, the water level still cannot rise 1 m (the rainfall) when I have opened the Temperature Module (Fig-0). It is still 1 m instead of 2 m. Please help me.By the way, in §4.2 of “THEORETICAL & COMPUTATIONAL ASPECTS OF EFDC+” (Fig-a), there is a basic equation of water temperature. However, I cannot find which term is associated with the wind field. Could you explain more about why “The equations that govern temperature in a water body require … the wind field”?

4

Hi In Art,Look at the equation for the full heat balance: https://dynamicsolutions-intl.atlassian.net/wiki/spaces/ETG/pages/100565009/4.3.2+Full+Heat+BalanceWind is a component of both the latent and sensible heat exchange terms.Regardless, after testing a similar model it appears that this is a bug. Thank you for bringing this to our attention. We will resolve it as soon as we can.Tom

5

Hi Tom, Does the bug mean that EE doesn’t consider rainfall as one component of water balance? That is, the rainfall is “useless” at present because of the bug? I am a little worried because rainfall in my study area is a major component of water budget. If the bug does ignore every volume of rainfall, my model will collapse because of the water balance. Thanks for your reply!

6

Hi In Art,The workaround for this bug is pretty simple. If you include evaporation, either in the aser.inp file or in EFDC_Explorer under the temperature module then it will use the rainfall. You have to set the option explicitly in the General tab of the Temperature module. See the screenshots attached.Tom

7

Thanks Tom! It works now. By the way, when you have time, could you please look at the questions about “How to input nutrient loadings instead of concentrations?” and “How to input long series of data based on limited measured water quality data?”?

8

Actually this is not so much a bug as a usability issue. The EE interface does not make it clear to the user that rainfall is not calculated in the water balance when evaporation options are turned off. We will clarify this in the GUI in an upcoming release as attached.