AS Geography Fieldtrip

AS Geography fieldtrip

The River Kym

The River Kym, called the Til in its upper reaches, is a tributary of the River Great Ouse. Its source is just south of Yielden, the river then continues to flow through Kimbolton, Great Staughton and Hail Weston, before joining the Great Ouse just north of St. Neots.

The purpose of this fieldtrip is to collect primary data for your Personal Enquiry (coursework). The trip will last one day and will involve you all (in one group), going to as many sites as we can manage (ideally as many as ten) and collecting information about; river velocity, cross sectional area, wetted perimeter and river gradient. This will provide all of you with the data you need to tackle your coursework successfully.

The day will involve a lot of getting off the minibus, working as a group to collect data, getting back on the minibus, going to another site and repeating this. Make sure you are prepared with:

·  Warm clothing, including a waterproof jacket and decent footwear – wellies would be ideal, although we hope to borrow some waders (you will be getting in the river!)

·  A packed lunch

·  Your recording sheets and writing implements (you can borrow a clipboard)

·  Bring a small towel, you’re going to get wet in November…..brrrrrr!

You must see me before the trip, either individually, or as a group, to ensure you are clear on what you will be doing and what you need to do as preparation.

River fieldwork techniques

Measuring river velocity

Method one: Measure out five metres (tape measure), mark off with ranging poles. Time how long it takes an object (i.e. dog biscuit) to travel the distance. Record onto your sheet (i.e. 20 seconds to travel 5 metres). Repeat three times to get an average at each site. You can work out the velocity back in the classroom (this would be 0.25 m/s).

Method two: Use a stream flow meter – stand in the river and record the velocity with the meter, writing the result down on your recording sheet. Again, this would be done three times to get an average.

With both these methods you need to decide where in the channel you will take the recordings (near the bank or in the middle, at the surface, in the middle or at the bottom of the channel). Which ever you chose, be consistent.

Measuring cross-sectional area

Measure the width of the stream, along the surface, with a tape (or meter rule) and measure the depth from the ruler to the bed of the river every 5 cm. You can plot the data easily when you get back to the classroom.

Measuring wetted perimeter

This is difficult, largely because you get wet! You need to measure the amount of land touching the water (i.e. you get a tape measure and measure along the bed/banks).

Measuring river gradient

You should be familiar with this. Place two ranging poles 5 metres apart and measure the angle between them with a clinometer (use trigonometry to work out the gradient).

Assume that you’ll be doing ten sites along the river, so prepare your recording sheets accordingly. I can give you a 1:25,000 map of the area, but it doesn’t have the whole river on it. You may want to get yourself the 1:50,000 OS Landranger map of the area. It is number 153.