Geography Fieldwork Flashcards
Primary data
Data collected by yourself
Secondary data
Data collected by someone else
How do u work out discharge
CSA (cross-section area) x velocity
How do u measure velocity in a river
Equipment used: hyroprop impeller & stopwatch
Method: choose sample site, place hydroprop impeller into the facing upstream, start stopwatch as soon as impeller starts to move, stop when impeller reaches the end, convert time into velocity.
Justification: to calculate discharge, to identify velocity changes downstream, repeatable easy, reliable and easy.
Evaluation: sediment can stop impeller from rotating, parallax error.
How do u measure depth in a river
Equipment: tape measure and meter ruler
Method: place tape measure from bank to bank and record length, divide width systematically, place meter ruler at the bottom of the river for each fraction, repeat systematically.
Justification: to calculate discharge, how depth changes along the river, repeatable.
Evaluation: parallax error, ruler on rocky ground-or at an angle, when water hits ruler due to resistance it forces water to move up the ruler creating an inaccurate data.
How do u measure width
Equipment: measuring tape
Method: measuring the tape across the river bank to bank, make sure tape is tight and at a straight point
Justification: to calculate discharge, find out the width, repeatable.
Evaluation: parallax error, changes by current
Field sketch
Equipment: pencil and paper
Method/justification: draw key features and labels describing if it is an increase/decrease of flood risk.
Evaluation: not to scale
Drainage basin
The area of land grained by a river and its tributaries
Watershed
An area of land that separates two drainage basins
Confluence
Where two rivers join
Source
The original point from which a river flows
Qualitative data
Non-numerical data eg. Opinions, surveys, drawings, photographs
Quantitive data
Numerical data
Discharge
The volume of water flowing through a channel at any given point. Measured in cubic metres per second = cumecs =m3/s
how to calculate risk
Risk = likelihood x severity