I would like to know about water quality model.
1. I want to model river water quality without water allocation system for urban area which is located along river.
2. And also I want to track water quality after proposed waste water treatment plant.
3. But I haven't some data such as groundwater inflow, groundwater outflow, evaporation, river flooding threshold, riverflood fraction and reach lenfth, loss from system, return flow routing, loss to groundwater, gain from groundwater.

Dear Nyein,

Have you completed the Water Quality module activities in the WEAP tutorial (available www.WEAP21.org/tutorial)? This will show you how to complete some of these tasks.

The best advice I can give you about missing data is that if you do not have the data you need to run the model (you may not need, for example, riverflood fraction, I don't know), the best you can do is make an educated assumption, and the a) explain this very clearly in your documentation and b) run a sensitivity analysis to report the impact of the assumption on the rest of your model.