# Hydrological uncertainty – Manning’s equation

**R – scottishsnow**, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)

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John Yagecic put out a great little blog post with accompanying app this week. He looked at the uncertainty from using vague parameters in Manning’s equation to estimate river flow. He made the great step of making the source code available. I forked this to the Open Hydrology repository and converted the project to metric units! Amazing! This is one of the big reasons I love open source: we can achieve so much more working together.

**You can use the metric version of the dashboard by clicking on this line.**

There’s one feature I’m really keen to add, which is adding a toggle to switch between depth and flow as an input (and getting the other as output). Having flow as an output is really useful if you’re trying to estimate flow, generally what a hydrologist does. However, if you’re a hydraulic engineer you have flow and want to estimate a level!

This is the first post in a new series, where I’ll look at communicating uncertainty in hydrological methods. If you’ve any suggestions for problems I should cover, put them in the comments below.

For those interested, the app was created using Shiny in the R language, which is a really nifty way to make interactive dashboards to investigate data and make decisions.

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