EFDC model allows us to use the dye module. We can use the dye module to calculate the age of the water. Under the sediments/toxics/others tab, there is an option to enter either the decay rate/age of water. To estimate the age of the water I used the dye module and assign the upstream cells of dye concentration 100. I am trying to simulate the pulse release here. What does the age exactly mean here ? In the view plan after the simulation it shows like at first the age varies between 1-100 as I assigned rest of the cells as 1. After doing the simulation how do we analyze the simulation results ? I am attaching a sample time series of age of water here. Please help me understand the age of the water concept here. If anyone could show the sample model or analysis that would be great Thanks. Jan
Hi Jan, Please see our newly updated guide to using this feature: https://eemodelingsystem.atlassian.net/wiki/spaces/HOW/pages/2378948/Age+of+Water+Tutorial
EE_Development_Team wrote: Hi Jan, Please see our newly updated guide to using this feature: Age of Water Guide Hi EE Development Team, I clicked the link, and there is no file available? Thank you. I would like to read more about the topic. Armi
This is the correct link: https://eemodelingsystem.atlassian.net/wiki/spaces/HOW/pages/2378948/Age+of+Water+Tutorial
I have recently gone through the guide and tutorial on the age of water. However, I am seeking a more comprehensive understanding of this concept, as well as the detailed methodologies involved in calculating residence time.
During my attempts to run a model, I observed that the age of water results were significantly high. I would appreciate it if you could provide insights into the factors that could contribute to these elevated values and suggest possible solutions or adjustments to the model.
Hi tzf0045,
I would like to answer your questions.
“I have recently gone through the guide and tutorial on the age of water. However, I am seeking a more comprehensive understanding of this concept:”
Answer:
The Age of Water is an important factor in relation to the residence time of water together substances in water environment. It reflects the time during which water remains within an aquifer, lake, river, or other water body before continuing around the hydrological cycle. Residence times of water in rivers are a few days, while in large lakes residence time ranges up to several decades.
“as well as the detailed methodologies involved in calculating residence time”:
Answer:
Age of Water Tutorial - EEMS8 Tutorials - Confluence (atlassian.net)
This link provides the method to calculate the Age of Water.
“During my attempts to run a model, I observed that the age of water results were significantly high. I would appreciate it if you could provide insights into the factors that could contribute to these elevated values and suggest possible solutions or adjustments to the model.”
Answer:
Some suggestions to reduce and ensure you achieve good results for the age of water:
- Ensure all boundary condition dye concentrations are set to 0 to simulate “new” water.
- Ensure your model has good calibration results (at least for water elevation/discharge) before checking the age of water results.
- Increase flow rates (velocity) by reducing Manning roughness, removing hydraulic structures, and so on.
Thank you! If you have any more questions or need further assistance, feel free to let me know.