HOW RIVERS WORK
Rives are always flow down hill. The source of the river is at the highest point which then flow down to the sea. Rivers are divided into three parts :
- Upper Course
- Middle Course
-
Lower Course
Upper Course
The upper course is the highest part of the river. Which is found on hills and mountains. The upper course of the river contains a lot of energy and its flowing fast. The river carries some materials like rocks. It erodes and makes the river channel deeper, and it makes valleys.
Middle Course
The angle in the middle course is not very steep. The erosion in middle course is mainly sideways. River channel in the middle course is wider and deeper. And it has bigger volume.
Lower Course
The lower course has the gentlest slopes. The land is almost flat, and it is known as floodplain. It has the deepest channel and the largest volume of water, and the slowest speed. It transports things like rocks. The river’s gradient is usually very slight and the
river has an increasing tendency to curve or meander the closer it gets to the coast
The Source
It is the original point in which the river flows. It may be a lake, a spring, or a pond-like.
Mouth
The place when river flows into the sea is called the mouth of the river.
There is a term called hydrological cycle. It begins with the evaporation from the surface of the ocean. When it is cool, it condenses and turns into a cloud. The moisture is transported around and it returns to the surface as precipitation. Some of the water may evaporate back to the atmosphere, or it may become the groundwater. Groundwater flows into the river, ocean, or it evaporates back.
Hydrological Cycle diagram
LOCATION OF THE AREA OF STUDY
www.map.freegk.com
Indonesia is located in South-East Asia.
www.cureblindness.org
www.radioaustralia.net.au
Bali is located between Java and Lombok
www.bewishbali-tour.com
Our project is located in Balian River, Tabanan, Bali.
METHODS AND TECHNIQUES
We measured the length, depth, speed, and the width of the river, both at the source and the mouth. We took samples from the estuary and the source. And we measured the temperature in the source and mouth.
We did the measurements per groups. There are five groups, each groups had to stick a pole in different sections besides the river banks. To measure the length, one person from each groups had to cross the river to the other side of the river banks with a measuring tape and the other person reads the measurements from the other side.
After we finished measuring the length, we started to measure the depth. At least two person from each groups has to stand in the river with a stick and a ruler. We stick the pole stick into the river bottom and measure it from above the water, we did this in every one meter or two of the river.
We measured the speed of the river with a stick. We throe the stick to the river, as the stick flows from the first point to the fifth point we record the time with a stopwatch. We did this several times to get the average speed.
We measured the temperature with thermometer. And the teacher took some samples of the water.
RESULTS
These are the measurement results. :
First Field Trip
Source
Mouth
Second Field Trip
Source
Mouth
ANALYSIS
First Field Trip.
Source
The location of the source on the first trip is on the mountains. The weather was good. The sky was clear. And the air was fresh
Large rocks are found in the source. Lots of trees, or maybe even woods, surrounding the source. The trees are quite tall. Beside the source there is a bridge and a roadway. Next to it laid a rice field.
The water in the source was quite clear. We found trashes in it, and the surroundings. There is a pipe, clear fresh water flows through it.
Mouth
The mouth located down the mountains, besides the beach. The sand is quite white. There is a residence beside it. A lot of palm and coconut trees and other plants can be found around the area. The water in the mouth is clear. There were rocks in the bottom, with some sand.
Second Field Trip
Source
The weather in the watershed area is quite good. It rained in the past 24 hours. It was a bit cloudy, but sunny. We found that the water was clearer than before. And we can see the bottom clearly. It seems that there are more rocks than before.
There were two women washing some clothes with the water in the source. It seems like the water is really fresh. We also found that there is less trash in the source.
There were small black fishes and tadpoles.
Compared to the first field trip, the depth of the mouth on the second field trip is deeper. The second trip is in the raining season. This means that because of the raining season the water level is increasing.
The trees and plants around the watershed proved that my hypothesis is true. And also the rocks are carried down by the river. There are large rocks at the source, it located in the mountains and the speed is not very fast,. There are steep slopes and we found that the land erodes because of the river.
Because of the raining season, the mouth gets bigger and the volume increases, it affects the flow of the river, it gets faster.
Mouth
It seems like the estuary is bigger. The flow is faster than before.
CONCLUSION
I found out that the river volume will increases during the raining season. Because of the increased volume the flow of the river is faster. And it erodes rapidly.
The river affects the surrounding. Because of the flow the land erodes. The water in the river are mostly fresh, especially at the source, we can use it to wash clothes. But it can make a water pollution in the river because of the trashes and stuff.
Small rocks are formed because of the erosion from the large rocks. The water breaks down the large rocks into smaller rocks. The river affects human, plants, and animals. We can not live without it
Note : I didn’t take photos during the fieldtrip
