NCERT Book Class 9 EVS Precipitation and soil erosion in the

4. Precipitation and soil erosion in the mountain ecosystem

Background soil erosion.

There are many natural and manmade factors which are responsible for soil erosion. Precipitation – rainfall and snow-fall – is one of the prime factors for such erosion. Soil as a resource supports human survival in so many ways. When erosion takes place it leaches away the valuable top soil of the area. The eroded materials that fall into rivers make the water turbid. Silting results in floods and even changes the course of the river.

Methodology

1. Go to a nearby river site and collect samples of water in transparent bottles from the river before rains, during the rains and after the rains.

2. Make sure that the sample of water collected each time is collected in similar containers and the volume of the sample is also the same.

3. Keep the samples undisturbed and find out the time the solid particles take to settle down in each case.

4. Decant the water after the solid particles settle down and compare the amount of sediments for each sample.

Conclusion

Prepare a report on your study giving possible reasons for variation in the amount of sediments in different samples.

Follow-up

Find out the various measures by which soil erosion can be checked.

Please refer to attached file for NCERT Class 9 EVS Precipitation and soil erosion in the