Homework for Tuesday 7th November
(a) Written work (in jotter)
"Standard Grade Study Mate"
Page 94-96, questions 1, 2 and 4; p.99 Q4 (Stuck? see http://www.scalloway.org.uk/trad.htm )
(b) Background reading
The Georesources website has a section on virtual fieldwork. Log on at http://www.georesources.co.uk/darentintro.htm to find out how the river changes downstream. You will also find references to fieldwork methods and equipment.
28 comments:
To find out about diferent particle sizes on the river bed take samples of the silt every 10m. The samples will show if the particles become smaller as you move downsrtream.
Sophie
To measure the width of a river use a measuring tape on a small river. However if the river is large like, the nile use a map and the scale to measure the width. The river should get wider downstream due to erosion.
To measure the slope of a river valley, stand at the top of the valley and point a clinometer down towards the river. Take the reading from the clinometer and repeat in several different areas and take an average.
the speed in which the river is flowing can be measured and the differents in speed from the outside of the river and inside of the river a flow water could be used firstly an the inside and then the outside to measure the speed in which the river is flowing. the outside should flow faster than the inside
the speed in which the river is flowing can be measured and the differents in speed from the outside of the river and inside of the river a flow water could be used firstly an the inside and then the outside to measure the speed in which the river is flowing. the outside should flow faster than the inside
To measure the depth of the river i would waded into the river and use a measuring stick at different points in the river.This would give an idea of where the river is deep and where it is shallow.
To find out the velocity of the river, a measurement should be taken at various points along the width and length of the river to give an accurate reading, using a flow meter.
To find out the depth of a river, you would use a metre stick, and measure at different points across the breadth of the river, from riverbed to surface, all the way down the length of the river.
To find the land uses of a river you would either look on an os map and see what the land is like around the river or go there and either ask a local or see for yourself what the land uses are.
To find out the amount of water flowing through a certain point, first the dimensions will have to be worked out. First take a small section of the river. This will require the average depth of the particular area and an average width of the particular area as well as the length. This will be done using a measuring stick and taking at least 3 readings to calculate an average. Finally, the speed of the river at that area will have to be worked out using a flow meter. Again, 3 or so reading should be taken for an accurate average to be calculated. Then, multiply the length, by width, by depth and come up with a volume for that area. The last calculation will be to multiply the volume by the speed of the water and the result should be a volume of water per second passing through the area chosen on the river.
The widht of the river is measure byusing a tape measure and as the river get large you may need to revert to a map because larger river have more eroision
Philip Palmer
To measure the slope of a valley use a clinometer and take angles every 10m. Repeat this and take an average.
Another way to measure particle size is by measuring the bedload( pebble e.t.c)Hence will be shown as to how the rocks change in size. There are two useful measurements to take. The first, the long axis of the pebble is shown in the photo on the left. It is being recorded using callipers but can be just as easily recorded with a 30 cm ruler.
The second measurement is the angularity of the pebbles. This can be recorded by observation using Powers' Angularity Chart (see picture on the left) which uses a set of six pictures to help you make your judgement.
Unless the stream bed is muddy or sandy, it is useful to take samples of the BEDLOAD. This can be measured to look for any differences across the stream and downstream from site to site. There are two useful measurements to take. The first, the long axis of the pebble is shown in the photo on the left. It is being recorded using callipers but can be just as easily recorded with a 30 cm ruler.
The second measurement is the angularity of the pebbles. This can be recorded by observation using Powers' Angularity Chart (see picture on the left) which uses a set of six pictures to help you make your judgement.
Unless the stream bed is muddy or sandy, it is useful to take samples of the BEDLOAD. This can be measured to look for any differences across the stream and downstream from site to site. There are two useful measurements to take. The first, the long axis of the pebble is shown in the photo on the left. It is being recorded using callipers but can be just as easily recorded with a 30 cm ruler.
The second measurement is the angularity of the pebbles. This can be recorded by observation using Powers' Angularity Chart (see picture on the left) which uses a set of six pictures to help you make your judgement.
Unless the stream bed is muddy or sandy, it is useful to take samples of the BEDLOAD. This can be measured to look for any differences across the stream and downstream from site to site. There are two useful measurements to take. The first, the long axis of the pebble is shown in the photo on the left. It is being recorded using callipers but can be just as easily recorded with a 30 cm ruler.
The second measurement is the angularity of the pebbles. This can be recorded by observation using Powers' Angularity Chart which uses a set of six pictures to help you make your judgement.
hi there
The WIDTH of the river channel can be measured by taking a 30 metre tape measure and stretching it from bank to bank. It should be kept as taut as possible to be accurate. If the stream bank is sloping, keep the tape as near to the water surface as you can so that you can line it up with the bottom of the bank.
the valley slope can also be measured as folllows:The two ranging poles are held vertically, about 10 metres apart (further if possible). The person with the clinometer holds it level with the bottom of the red stripe and looks through the sight to the same position on the other pole. For this method, a gun clinometer cannot be used.
External Pressure (Depth) Monitoring Systems with Telemetry
Clean water or reservoirs can be monitored with submerged pressure sensors connected to any Radcom logger with an external pressure input.(merry cristmas) Calibration is stored within the logger such that real engineering depth units or are accessible from the data logger (Metres, mBar etc.....ho ho ho ! ).
To measure the slope of the valley, the two ranging poles are held vertically, about 10 metres apart (further if possible). One person holds the clinometer level with the bottom of the red stripe and looks through the sight to the same position on the other pole. The angle should then be recorded. For this method, a gun clinometer cannot be used.
measure the DEPTH of the stream using a metre rule. Measure depth in metres e.g. 0.25 for 25 cms. so that width and depth measurements are the same units. Regular, accurate readings will allow you to draw an accurate cross-section of the stream channel.
Possible problems: large boulders or debris may make the stream very shallow at a particular point - record the reason for this on your data sheet. If the stream bed is soft, the ruler may sink into the mud.
The speed or VELOCITY of the stream can be measured in two ways. If you have a flowmeter, this allows you to take accurate readings at different positions across the stream and also at different depths if you wish. Ideally, you should take at least three readings - in the centre, close to the left bank and close to the right bank. This will allow you to see the effects of meanders on the position of the fastest current. The flowmeter has a propeller which turns in the moving water. The number of turns is recorded on a digital counter.
If you do not have a flowmeter, you will need to play 'pooh sticks'. Measure out a length of stream, five or ten metres is ideal. Float a small stick, an orange or similar object along the stream and time how many seconds it takes to get from marker one to marker two. The velocity can be calculated using the formula: speed = distance/time. Ideally, do this two or three times to get an average.
However, flowmetres can break,so cannot always be reliable, and floating an object along goves the surface velocity, but not the maximum velocity.
To measure the velocity of the river you can use a flow meter or pooh sticks. You should take measurements at various points in the river and at both sides and in the middle. Pooh sticks can be used if you have no flow meter. You measure a distance of maybe 10 metres and then put in a stick and measure how long it takes for the stick to travel between the 2 points.
philip
(Winceby Beck)Near the source the river is flowing quite fast,probably because the land is steep. Further down the river flows slowly because it is flatter and there maybe lots of meanders and debris in the water. The river speed increases again as it nears the mouth as the river is straighter and there is more water in it from tributaries so there is more power which makes it go faster.
Homework-From the Graph
At the upper course the river flow faster as it flows down hills and there are often waterfalls. In the middle course the river slows down as it has picked up many particles from the lower couse and is meandering. It picks up speed again in the lower course as it has began to drop its silt and straighten out which means it has picked up speed again.
Homework from the graph
The velocity of the winceby beck at the source is strong in the upper course as there are many steep drops and waterfalls. However the velocity then decreases in the middle course as the river is transporting materials and there is alot of meanders. Once the materials have been dropped the river will increase its speed and as the land is flatter in the lower course. Also many tributaries contribute to the speed of the river as well as the volume of water.
woof
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