River Study Fieldwork

1
River Study Fieldwork
2
Planning

• Why Whitewater River
• Close proximity to the school/Killowen Outdoor
  centre
• Studying rivers/fluvial environments in Module 1.
• The river could be easily accessed and the sites
  could be reached from the road (accessibility).
• Data could be safely collected at this river
  (safety aspect). A risk assessment had been
  completed by the teachers prior to the fieldtrip
  to determine that this was the case. Nice clear
  water so we could see where we were walking
• Discussed in class what to measurements would be
  taken and how eg Width, depth, wetted perimeter
  etc
• Students were informed how to use the equipment
  required for the above measurements and record
  results.

3
Health Safety Issues

• Obtain permission from Parent(s)/Guardian(s)
  letters home
• Collect medical information eg asthma take
  inhalers
• Take into consideration the size of the group
• Behaviour of students fully co-operate with
  leaders and teachers
• Consult a weather forecast
• Check each site for access and safety
• Carry a first aid kit
• Wear warm and waterproof clothing/protective
  clothing (helmets)
• Inform others of your destination and time of
  return
• Bring a mobile phone

4
Health Safety in the field

• Wear helmets. Buoyancy aids must be worn with
  waders. Carry a throw line.
• Be aware of slippery and uneven surfaces
  rocks/boulders.
• Use the equipment properly. Take care with
  hazardous equipment eg ranging poles.
• Potential hazards include Weils disease and giant
  hogweed vegetation.
• Strong currents.
• Variable depths of water.
• Overhanging banks.
• In the event of an accident, remove everyone from
  danger, apply first aid, phone for assistance and
  stay together.

5
Overcoming Hazards
Hazard How to overcome it
Deep Water / risk of drowning Wear buoyancy aids, thrown a rope line
Uneven surfaces / slippery rocks, body injuries Wear a helmet in case someone slips
Cold, hypothermia, death Wear a few layers rather than just one thick one
Weather conditions Watch the weather forecast plan accordingly
Water quality weirs disease Wash hands thoroughly, cover open cuts, bring a first aid kit and antiseptic wipes
6
Primary and Secondary Data

• PRIMARY DATA that collected in the field, river
  width, depth, gradient, GPS co-ordinates etc
• SECONDARY DATA
• Ordnance Survey maps for altitude, distance
  from source (see table)
• Weather forecast bbc.co.uk

7
Sampling Methods

• What is the aim of sampling? It is impossible to
  due to time and resource constraints to test
  everything therefore sampling becomes necessary.
• Systematic sampling was used for sites.
• Random sampling was used for bedload.
• Stratified sampling is used for an area which has
  two distinctive areas e.g a rocky and sandy area
  on a beach.

8
What did you do?

• To investigate how a river can change downstream,
  it is possible to examine a local river
• Any river may be divided off into 3 main sections
  called courses upper, middle, lower.
• Various fluvial characteristics are measured at
  regular points (10 Sites) along the White Water
  river
• This type of sampling is called systematic
  sampling and it allows the investigation of
  continuous changes as distance increases from the
  source of the river
• How are these things measured?

9
Aim of Fieldwork

• To investigate several physical characteristics
  of the White Water River and how they change from
  source to outflow
• The 6 characteristics we have chosen are
• 1. Velocity (metres/second)
• 2. Width (metres)
• 3. Depth (cm)
• 4. Wetted Perimeter (metres)
• 5. Bedload size (cm)
• 6. Gradient (degrees)

10
Hypotheses to be Tested

• The river and its channel get wider as you travel
  downstream.
• The depth of the river increases as you travel
  downstream.
• The velocity of the river increases as you travel
  downstream.
• The size of the bedload decreases and its
  roundness increases as you travel downstream.

11
Width

• This is measured by placing one end of a
  measuring tape at one side of the river channel,
  then pulling it out to the other side of the
  channel
• The distance is the width of the river

12
Depth

• This is completed using a metre stick
• It is lowered into the water every 10 cm, and the
  distance from the top of the water to the river
  bed gives the depth of water
• An average of all these readings is taken

13
Discharge

• This is the amount of water passing any point in
  a river in a certain river, normally given as
  cubic metres of water per second (cumecs)
• It is calculated by multiplying the
  cross-sectional area of a river channel at a
  certain point by the speed (velocity) of the
  river at the same point
• The cross-sectional area is obtained by
  multiplying the width of the river by the average
  depth
• The speed (velocity) of the river is recorded
  using a flow meter (a small propeller attached to
  a rod) that when dipped into the river gives a
  digital reading of the speed of flow in metres
  per second
• Can also be recorded manually using flotation
  objects such as twigs placed in the centre of the
  river. These can be used to estimate the surface
  velocity by timing the twig travelling a distance
  of 10m

14
Load

• The load of a river is the material it is
  carrying, ranging from small sediment to large
  boulders
• It is very hard to measure the size of the load
  in suspension, so instead, we can concentrate on
  the load lying on the channel bed called the
  bed load
• This load is measured for size and roundness
• By measuring the longest axis of 15-20 random
  samples at each point an idea of the size of the
  load is obtained
• Each stone is then given a rating for roundness

15
Wetted Perimeter

• This is the surface of the bed and banks, which
  is in contact with the water in the channel
  measured by a tape, weighed down with small
  stones across the river or with a chain

16
Gradient

• The angle at which the river is flowing
• This can be found using a clinometer, whereby 2
  ranging poles are set 10m apart, parallel to the
  bank and the inclined clinometer indicates the
  angle one is from the other

17
Improvements to fieldwork

• Visit more sites more than 10 sites.
• Take more readings to improve the accuracy of the
  data collected. The bigger the range in your
  sample, the more samples you should take to
  reduce errors e.g river depth.
• Use digital equipment for data collection.
• Same students collect the same information at
  each site to ensure consistency in the results.
• Allocate more time with the data collection not
  rushing making errors.
• Compare results different time of year /
  different river
• Compare results with other schools.
• More practice in using equipment to improve
  accuracy.
• Measure velocity always along the same transect
  as where you measured width to ensure accurate
  cross sectional area and so discharge