The Flooding of Topsoil

Erosion

• Flood waters can be extremely damaging for farmers and landscapers when erosion occurs. Erosion results when excessive rainwater saturates soil, which often occurs in the flat areas of crop lands. Rainwater soaks soil to the point that it cannot absorb the rainwater fast enough. The result is a rushing flow of water that will diminish the topsoil if it is strong enough to pick up individual soil particles. The flood waters flow down a slope or across a plain, taking soil with it and causing erosion of topsoil.

Main Causes Of Topsoil Loss

• In its natural state, many landscapes are designed to absorb water, but urban environments tend to worsen flooding issues. Impervious pavement creates large amounts of storm water runoff that cannot soak into the ground. Instead, the water builds force enough to pick up soil particles. Bare swaths of land can create the same problem for the flooding of topsoil as tree and vegetation roots would otherwise help anchor it. Soil is carried away, leading to overflowing rivers and serious flood disasters.

Preventing Topsoil Loss

• An important approach to preventing topsoil erosion on farmland and in urban areas is to include waterways and drainage ditches in between fields and land plots. Avoid bare soil by planting vegetation such as trees in open areas and add mulching between plants. The mulch slows down the impact of rushing water and soil. Vegetation serves as a natural flood control and prevents erosion due to the anchoring effect of roots. With new approaches to urban planning, cities are designed with porous surfaces, which allows absorption of rainwater and prevents devastating storm water runoff.

Disasters

• Topsoil flooding accounts for devastating natural disasters that are perhaps made worse by urbanization and deforestation. In 2004, floods and mudslides in Haiti killed thousands of people after heavy rains hit a mountainous area and nearly wiped out a town. Satellite imagery from NASA revealed that the flood waters followed pre-existing river channels from previous floods, but also created new channels. Scientists believe the recent flooding was worse due to deforestation, which encouraged the movement of soil and rocks from the bare hills and prevented rainwater absorption.