river fieldwork

what are the two types of samplings used?

• we went to 5 sites, we use used a convenience sampling to sample 5 different river sites depended on where we had access to river

• we used systematic sampling to sample 5 locations for depth and number of stones

what are the risks associated with river fieldwork?

• risk of slipping

• risk of getting washed downstream

how did we overcome these risks?

• we chose our sites thinking about safety for entering the river and made sure the river was not too deep or too fast

• we made sure the land was public access so landowners would not get cross

how are channel sediments measured for shape and size?

• we measured the length of the stone with a ruler and categorizes it with the power index according to its angularity and sphericity

how is width measured?

2 people hold a measuring tape taut at the surface of the water and measure the distance from one bank to another at the level of the water to measure the width in cm and m

how is depth measured?

• a one metre rule is used

• 5 distances are taken across the river at regular locations e.g. the first one is at the left bank looking upstream and the last is at right bank

• the metre rule is put into the water until it reaches the bed and the reading is taken from the top of the water

how is wetted perimeter measured?

a chain is used to measure the wetted perimeter

how is the gradient of a river measured?

we used a clinometer to measure the angle of gradient

how is velocity measured?

• a distance of 5 metres is measured down the centre of the river

• an orange is placed into the water and the stopwatch is started

• the time is recorded for the orange to travel 10m, using the formula speed= distance/time, we can find out the velocity

• this is repeated 3 times

how is CSA measured?

cross sectional area is the width x the average depth

how is discharge measured?

uisng the formula CSA x velocity

what were 6 of our river data collection methods?

• width

• depth

• csa

• velocity

• stones

• photos and annotated field sketches

unreliable methods- choice of sampling

we only went once in the summer season.  Repeating measurements at different times and seasons would have improved reliability

unreliable methods- external factors

River conditions can vary due to factors such as weather and human activity in the river, meaning my results may not be representative over time.

• weather conditions

• time of the day

• environmental factors

unreliable methods- choice of sites

• we only chose 5 sites, which is a small number of sites that were sampled. this may not accurately represent the entire river's characteristics

• A larger sample size would have increased the reliability of my findings.

how could width measurements be unreliable?

River width was measured using a tape measure stretched across the river. This method was generally accurate, but human error in reading the tape or measuring at inconsistent points could have led to slight inaccuracies.

how could velocity measurements be unreliable?

• To measure velocity, I used a floating orange and my partner timed how long it took to travel a set distance of 10m.

• However, this may not have been completely accurate as the velocity of the orange it may have been affected by external factors such as wind and obstacles in the river, and my partner may not have been consistent in stopping the stopwatch precisely when the orange reached the set distance

how could depth measurements be unreliable?

we may not have held the metre rule upright, this could be improved by using a set square or a clamp to ensure the metre rule is held vertically

how could field sketches and photographs be unreliable?

• we only took one photo at Location 1 and 5 and our sketches weren’t very accurate

• this could be improved by taking more photos at each location to give a clearer representation of the river, therefore for an accurate result

how could stone measurements be unreliable?

it is somewhat subjective for one person to say how angular a rock is and it was difficult to measure the long axis accurately

• this could be improved by using a protractor or angularity chart for consistency

• we could measure the long axis with a measuring tape for greater accuracy

how could wetted perimeter be unreliable?

this data was not collected by each of us, we should have collected this to improve our study

what are our data presentation methods?

• bar graphs

• inverted column chart

• cross-sectional graph

• flow lines graph- not precise enough, didn’t use a ruler

• proportional circles map- vague, doesn’t show exact discharge and measurement matrices

• column chart

• annotations- lack of detail

how can GIS support fieldwork?

• locate where we are, so we could see which sites were accessible and safe

• find longitude and latitude

• find out where tributaries joined the river to explain our results

how can ICT support fieldwork?

weather reports were used to see what the weather conditions were prior to us going for safety reasons and to explain our results

How could gaining secondary sources help fieldwork?

• studies of river flow

• river regimes- shows the discharge of the river over a course of a year- this demonstrates how it differs with different weather conditions, which helps us explain our results