Questions that focus on changes along the long profile or downstream changes support in developing a hypothesis. A hypothesis is astatement, usually an educated guess, that you will either prove or disprove through the data you collect as part of your investigation. Primary Field Work Techniques Tip: If the bed is rough and bumpy, you will need more measurements at closer intervals to get an accurate result. Students are challenged to match eight features of river systems to photos, satellite images and maps. This activity can easily be differentiated by giving groups different numbers of cards.

The discharge of a river is the volume of water flowing through a river channel. It is usually measured in cubic metres per second. Measuring the width of the river channel enables you to calculate the cross-sectional area. Also, according to the Bradshaw Model, channel width increases downstream. Measuring the wetter perimeter of a riverCoastal Environments CPD – Erosional Landforms, Coastal Management and Fieldwork on the Holderness Coast To calculate the cross-sectional area you will need to know the mean depth. According to the Bradshaw Model depth increases from the source to the mouth of a river. Measuring river width The velocity of a river is the speed the water flows. The velocity will change along the course of a river. There is a range of things you can use for a float including an orange. We recommend dog biscuits because they break down in water if swept away! River cross profiles show you a cross-section of a river’s channel and valley at certain points in the river’s course.

The Bradshaw Model suggests that certain changes occur along the long profile of a typical river. For example, discharge increases as you move downstream of a river or bedload (material on the river bed) particle size decreases along the river channel. mathsf{Discharge \;(m

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Place a metre ruler into the river until it touches the river bed. Record the distance between the river bed and the surface of the water. You should do this at regular intervals between the banks of the river. Add the depths together and divide by the number of recordings you took to calculate the mean depth. Extend a tape measure from the point where the dry bank meets the water on one side of the river to the same point on the other side (hold it taut about 20cm above water level). Record the length, viewing the reading from directly above the tape measure.