Hydro v5.0 evapotranspiration bug

Issues related to i-Tree v6.x can be posted in this section. 6.x updates and known issues will be posted here also.
Post Reply
i-Tree Team
Posts: 46
Joined: Fri May 08, 2015 9:29 am
Location: Syracuse, NY

Hydro v5.0 evapotranspiration bug

Post by rcoville » Thu May 05, 2016 2:21 pm

We've identified a bug in which evapotranspiration (ET) does not reset at each timestep. The code is incorrectly accumulating ET from timestep to timestep. Changing this greatly affects the pervious and impervious flow. This is due to the fact that the cumulative infiltration calculation is:

Code: Select all

cumInfilQ = cumInfilQ - 0.1*(BQ + rET)
Where cumInfilQ is cumulative infiltration, BQ is base flow, and rET is actual evapotranspiration.

With an incorrectly steadily increasing ET, we're underestimating cumulative infiltration which is allowing for much greater infiltration at each timestep and underestimating pervious area saturation excess and infiltration excess runoff.

This is a known issue which will be resolved in the next update to i-Tree Hydro version 5.
A member of the i-Tree Team

Please provide feedback on our technical support services by clicking here to take our 5 minute survey
Post Reply