# Invest water yeild model

**URL:** <https://community.naturalcapitalalliance.org/t/invest-water-yeild-model/830>\
**Category:** Science, Research & Data\
**Tags:** annual-water-yield\
**Created:** [February 24, 2020, 4:18am UTC](https://community.naturalcapitalalliance.org/t/invest-water-yeild-model/830 "2020-02-24T04:18:15Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![swolny](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/swolny/32/181_2.png) [@swolny](https://community.naturalcapitalalliance.org/u/swolny)\
**Post date:** [February 27, 2020, 3:55pm UTC](https://community.naturalcapitalalliance.org/t/invest-water-yeild-model/830/7 "2020-02-27T15:55:52Z")

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Hi @caoxiaoran -

The [User Guide has an Appendix](http://releases.naturalcapitalproject.org/invest-userguide/latest/reservoirhydropowerproduction.html#appendix-1-data-sources) that gives a few sources for the biophysical table data, as well as several ways of estimating the Z parameter. For Kc and root depth, we do a literature search for studies that have been done in the places we’re working, or places that are similar in land cover and climate. It is definitely a very time-consuming process, even for these simple models.

~ Stacie

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