NOTE that this App has been updated to support iOS6 and the 4 inch retina screen

A new app is born
I have finally released (and debugged and re-released) the NotchFlow App on the iTunes store. The App is available globally, so if you don’t have access to the US store, please try your local one.

NotchFlow calculates the flow-rate of water passing over the top of a fully contracted V-Notch weir by simply measuring the height of the flow above the bottom of the weir. In addition to calculating the flow, NotchFlow also estimates the population that could be supported by a given flow-rate using one of five predefined per capita water usage profiles.

However if that is not what you want, NotchFlow can perform its calculations three different ways:

  • Flow and population calculated from a given height
  • Height and population calculated from a given flow
  • Height and flow calculated from a given population

Additional information about the App can be found on the NotchFlow website

Pretty Pictures
Here are some screen shots of the NotchFlow App:




Weir Design

The Calculations screen shows the flow and population being calculated from the given height, but also allows the other two calculation types to be easily selected.

The Preferences screen shows the three main configurable preferences:

  • The units system: Metric, Imperial and US
  • The per capita daily water consumption profile
  • The actual notch angle used in the weir under consideration

The Information screen shows the wide range of information and design notes built into NotchFlow.

Finally the Weir Design screen shows part of the design notes available to help build the correct weir shape.

Stealing ideas
The basis for the calculation part of the App was “borrowed” from United States Department of the Interior, Bureau of Reclamation’s Water Measurement Manual. This publication describes the basic calculation needed to determine the flow-rate as well as providing notes on how the weir itself should be constructed. The NotchFlow App contains a summary of the design notes from that site with enough detail so that the proper weir can be built in the field.

The pre-defined per capita water profiles were adapted from the classifications defined in the WHO Guidelines for drinking-water quality. The WHO classifications aim to relate the level of public health risk for a person based on how much access they have to clean drinking water.

I hope people find this App useful, and I look forward to releasing my next App!

Ciao, Peter