Thermal simulating with EFDC

Hello All,
Is it possible to use EFDC for this case: a river flows into a bay, and a discharge location for a WWTP is proposed at a branch of the river; we want to simulate the thermal impact of this effluent on addressing air link, e.g. air temperature, solar radiation, etc.
Thanks for your suggestons,

Hi Shen, Yes, EFDC can handle this case very well. The WSER and ASER files will need to be specified. If you are using EE this is quite simple as it will assist you in setting them up. You may want to look at our Water Quality Example to help you as it has atmospheric inputs. It is downloadable from this page: Test case models

By choosing Equilibrium Temperature (CE-QUAL-W2) sub model, will EE use the same set of parameters as Full Heat balance sub model? It is not described in EE manual. Since external equalibrium temp (ISTOPT = 2) and constant equilibrium tempearture coefficient (ISTOPT = 3) will use a different set of atomosphere parameters, I am wondering whether EE added ISTOPT = 4 will use a different set of them.

If the CE-QUAL-W2 sub model is selected then different parameters are required. These parameters are outlined in the CE-QUAL-W2 manual.

Thanks. So the list of atomospheric parameters will be different, as seen in the “Atomospheric Parameters” window.

What about the time series parameters, including: air pressure(PATM), dry temperature(TDRY), relative humidity(RelH), rain (RAIN), evap (EVAP), solar radiation (SOLR), cloud factor (CLOUD)? Does CE_QUAL_W2 uses the same set of parameters as indicated by corresponding headers? Are all these parameters used in calculation, in other words, can I omit some parameters?

If I choose to evaluate EVAP internally, do I still need to put EVAP column with some meaningless numbers as place holder for record reading?

For the rain(RAIN) parameter, is it just rain or precipitation (rain + snow)?

Thanks again for your clarification

It is recommended that you use a column of zeroes as a place holder for EVAP. The RAIN parameter is total precipitation.

We are trying to set up thermal model non-time series parameters, and not sure what is a reasonable thermal thickness and bed temperature.
- the Lake_Example from EE website uses 1 m for thermal thickness, but the model domain water depth is > 40 m; our model domain has water depth within 1~3m, what would be a reasonable thermal thickness, is it related to sediment depth? Can you refer any publications on this issue?
- results from Lake_Example show bed temperature and thickness does not change with time: thermal thickness is kept at inital although it is spatially varied, and bed temperature is kept at 1 deg C everywhere? Is it supposed to be so?
- I think the bed temperature should change with time, e.g. in summer it should be higher while in winter it should be lower, especially for shallow river. Is EFDC able to simulate time varying bed temperature?

In the Lake Okeechobee example the initial bed temperature = 18.4 C and thermal thickness of the bed is set to a constant 1 m over the model domain. If the thermal thickness of the bed is set to a –ve then the thickness can vary spatially over the domain by setting the TEMB.inp file. This is not the case for this example and there is no TEMB.inp file. The thermal thickness of the bed is constant over time. However, in this example the “Heat Transfer Coefficient between Bed/WC” was inadvertently set to 0, meaning there was no change in the bed heat. This should be set to a more appropriate value, typically 0.3.