calculation of hydrology effect

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Sam1026
Posts: 1
Joined: Thu Jul 16, 2020 8:28 am

calculation of hydrology effect

Post by Sam1026 » Thu Jul 16, 2020 9:19 pm

Dear i-Tree team,

I've learned that when Eco calculate the Avoided Runoff, the model will use the study of Nowak and Greenfield (2002),in which the impervious cover(IC%) and pervious cover(PC%) is set by 25.5% and 74.5% respectively, and that's the situation of the contiguous United States.

My question is:
1. Can international users change these settings with the IC% and PC% data of our own project?
2. Or,if I want my project result be more accurate, how should I calibrate the model result?

I appreciate your support and look forward for your response.

Best
Sam
azelaya
i-Tree Team
Posts: 368
Joined: Fri Jun 27, 2008 10:50 am

Re: calculation of hydrology effect

Post by azelaya » Fri Jul 17, 2020 8:51 am

Hello Sam,

Thanks for your question and taking time to point out this default setting which influences hydrology effects for all Eco projects. Unfortunately, the Eco model does not have the ability to allow international or US users to use their own settings based on actual ground cover characteristics. We have proposed the idea of using the ground cover information that is available in Eco plot projects as a more accurate representation but that also requires significant model modification to implement for individual projects and is not available for complete inventory projects. For US users, Hydro offers more control over these settings but is a different type of model and usually not a viable or easy alternative.

I will have to check with our Developers/Modelers to see if it is possible to have the default ratio integrated in the new international location entry process for Eco where a value could be applied - or updated - for a country that is more representative as opposed to using the US ratio.

Unfortunately for now this is a limitations...and I will update this post at a later date with any possibilities to improve this.

Thanks again,
Al
A member of the i-Tree Team
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