# Calculators & spreadsheets

## Channel flow calculator

This online tool calculates the flow of water in a rectangular or trapezoidal channel

## Dam bank volume calculator

This calculator uses the "average end area" method to determine the volume of a trapezoidal shaped dam bank.

## Level reduction spreadsheet

This simple "Excel" spreadsheet calculates reduced levels from raw survey data using the "rise and fall" method. Data is entered in the same way as with a traditional survey book. The data would normally originate from a dumpy or laser level.

## Tacheometric reduction spreadsheet

This "Excel" spreadsheet calculates reduced levels and rectangular co-ordinates from a theodolite or similar instrument. It requires data to be entered in the form of a horizontal bearing with the degrees and minutes entered in separate columns. The vertical angle is entered as decimal degrees, and the stadia readings entered as "Top Hair", "Middle Hair" and "Bottom Hair" respectively. It is important to note that the accuracy of the results are limited to a horizontal bearing of 1'. The station reduced level and instrument height can also be entered into the spreadsheet.

## Dam bank volume spreadsheet

This "Excel" spreadsheet calculates the compacted volume of an earthen bank using the "End Area" method. The elevation along the centre-line of the bank is entered into the spreadsheet from one end of the bank to the other. The respective distance between each elevation is entered in the second column. Other data required is the slope of the upstream and downstream bank batters, the width of the top of the bank ("crest width") and the elevation of the top of the bank ("crest level"). It is important to note that the elevation data can be entered in as a level reading or in the reduced level format.

## Stadia reduction spreadsheet

This "Excel" spreadsheet calculates reduced levels and rectangular co-ordinates from raw survey data. The raw data is entered in the same way as in a traditional survey book with the stadia readings entered in the "Top Hair", "Bottom Hair" and "Bearing" columns respectively. The Horizontal bearing ("Bearing") needs to be entered in a decimal format. Normally this spreadsheet would be used for entering data from a dumpy level or similar instrument. Once the raw data has been entered and rectangular co-ordinates calculated, some transposition of the data may be required to avoid negative co-ordinates. This is simply achieved by finding the largest negative figure in each or the "X" and "Y" columns, and adding this as a positive figure to all the data in each column respectively.