The document outlines a methodology for investigating how channel size, efficiency, and gradient change with distance downstream. It presents 3 hypotheses and describes primary data that will be collected, including cross-sectional area, velocity, discharge, wetted perimeter, hydraulic radius, gradient, and roughness. Secondary data on climate, human management, and geology is also deemed relevant. A risk assessment is required and must be linked to the methodologies. Specific methods are described for measuring cross-sectional area, including using ranging poles and a tape measure to find width and depth at points across the channel. Calculations and a justification are provided. GIS use is recommended for maps, risk assessment, and collecting secondary data.

1. Methodology

2. What do the examiners say?

3. Hypotheses
1. Channel size or Cross Sectional area will increase with
distance downstream.
2. Channel efficiency will increase with distance from the
source.
3. Channel gradient will decrease with distance
downstream.

4. Methodology Areas
PRIMAY DATA
 Cross Sectional Area (width and average depth)
 Channel Velocity
 Discharge (CSA x Velocity)
 Wetted perimeter of channel (channel efficiency)
 Hydraulic radius
 Channel gradient
 Channel bed roughness

5. Methodology Areas
SECONDARY DATA
What types of secondary data may be useful in your
investigation? What might they tell you about the river?
 Climate of the area?
 Human management of the river?
 Vegetation & Geology of the area?

6. Risk Assessment
 You must complete your own risk assessment for the
fieldwork.
 Should include environmental, human and equipment
hazards and risks
 Needs to be a clear link to your methodologies

7. Ranging poles placed at the
wetted edge of the current
river channel.
Tape measure held taut at
90° to the river channel
attached to ranging poles to
measure channel width
Depth measured at 11
evenly distributed points
across the wetted river
channel starting from the
left bank
Large irregular rocks
associated with the upper
course throughout the
channel.
Channel edge during the
wet season
Measurements taken from
left to right as you look
down stream
Tape held about 20cm
above water level so a
metre rule could be used to
measure depth evenly
across the channel.
Annotated
Photograph

8. CROSS SECTIONAL AREA
Description & Explanation of Method
Justification
Risk
Assessment
Channel width and depth will be measured at each site using the equipment
This method will give an
Linked to Risk 1a,
and method as outlined below.
approximation of how
b, 2b, 3d
channel size changes
downstream and will show
variations in depth across the
channel.
By calculating the cross
sectional area of the river,
along with the wetted
perimeter, we are also able
to determine the channel
efficiency (Hydraulic Action).
It will also provide us with
By calculating the channel width and average depth we are able to work out the
cross sectional area (CSA) of the channel at each site. This is worked out using
valuable supporting evidence
when compared to river
velocity and also discharge.
the below formula.
CSA = Width x Average Depth

9. Use of GIS
Clear use of GIS and well linked to the chosen question
 Area of Study & Location Maps – Google Earth
 Risk Assessment
 Secondary Data collection