Does anyone have any experience or references to modeling water temperature in SWMM? We're interested in having the temperature as a water quality/pollutant parameter for an existing collection system model in SWMM. If possible, we'd prefer to do so within SWMM itself or at least be able to link the existing model up to a separate temperature model. Any advice is appreciated!

Big ask!

Try searching the JWMM paper archive for various search terms incl. thermal enrichment:

https://www.chijournal.org

Thanks Bill for the paper but if Ben wants to just model temperature as either a mass balance conservative constituent or as a reactive constituent with a decay term he can do that in the existing SWMM 5 engine using the existing SWMM 5 GUI. It would at least allow a modeler to mix waters of different temperatures and have a mass balanced mixed temperature in the pipes. You could also use a decay term to make the water colder as it moves through the pipes and perhaps make the water warmer as it moves through the pipes. The SWMM5 treatment equation is very functional.

My apologies is this is completely not what Ben is intending to model. It is certainly not similar to the past papers by Bill and his students about modeling thermal enrichment in SWMM 4. It is more of an approximation.

Perhaps Ben can clarify the intent. If he needs to model how rainfall warms up when in contact with hot paved surfaces, and then how this warmer runoff potentially increases the temperature of the receiving stream, pond or other water body, then the thermal enrichment heat balance would be needed. On the other hand, if the intent is to model temperature as storm water travels through the conveyance system, then it may be possible to use the water quality routing within SWMM5 as Bob suggested, however, keep in mind a mass balance is not quite a heat balance which is needed here, and the approximation using a decay term doesn't exactly represent the heat exchange between the travelling liquid and the surrounding walls and/or air. The latter should involve the use of the Fourier Law and appropriate heat exchange coefficients. If the decay term is to be used, separate analyses should be conducted to have an idea of how heat is lost as water moves down the conveyance system.

Thanks Bill, Rob, and Mauricio for your responses! Our high level intent is to model the temperature of stormwater and combined sewer water as it travels through the conveyance system. I had wondered if a mass equivalent method could work for us, but I hadn't seen any examples of its use or validity. This method could provide a stepping stone, though if we can find any research on modeling heat exchanges within a collection system, we would probably lean towards exploring the more complete modeling approach.

"..Our high level intent is to model the temperature of stormwater and combined sewer water as it travels through the conveyance system. .. "

Ben,

How do you intend to convey and distribute the heated runoff between the street surface system and storm sewer system to model realistic conditions in EPA SWMM?

As you probably know the storm sewer system is typically designed for the Minor Storm design event. Just curious what storm event(s) are you modeling in this endeavor?

For each design event you will want a realistic distribution of the runoff between sewer flow and street flow to assess the correct mixing of temperatures or pollutants.. For example, without the correct volumetric distribution between the two systems that takes into consideration interception and bypass flows, by the time you get to the bottom of the street, your temperature and pollutant distributions between sewer flow and gutter/street flow will be inaccurate.

This could have important implications depending where the flows from the two systems are being conveyed. For example, the sewer flow could be conveyed to a regional detention facility, where the street flow may be conveyed and offloaded to a stream or urban canal structure.