Construction projects seem like an innocuous and everyday part of life. However, are they contributing to environmental problems? Do construction projects increase the rate of erosion?
Construction projects can increase the rate of erosion due to the process of grading – leveling the ground. As grading occurs, a lot of vegetation is uprooted from the spot. The roots of these tiny plants keep the soil and dirt in place, but after leveling, the ground is easily movable.
In this article, we’ll take a look at the definition of soil erosion, why it’s so harmful to the planet, and how construction projects inadvertently end up causing soil erosion. Keep reading!
How Do Construction Projects Cause Soil Erosion?
Construction necessitates the movement of the earth and soil to form buildings and other structures.
Construction projects cause soil erosion as they dig up the area and displace the natural ground. The natural process of erosion is slow, but construction disturbs the soil, speeding the process up. Construction projects often have anti-erosion measures, but these are usually not 100% effective.
Grading is the act of leveling the ground to form either a smooth base or slope to create the foundation for building roads, railway tracks, or buildings.
While soil can be moved with man-made equipment, it can also be moved by the wind and water, which results in further soil erosion.
Although construction only affects the topsoil of the area where something is being constructed, its effects are extremely environmentally negative.
What is Soil Erosion?
Soil erosion is the removal of topsoil, the most fertile layer of soil, usually caused by environmental factors like water or wind.
Although topsoil can regenerate, it does so slowly. According to a senior UN official, the regeneration of three cm (1.18 in) worth of topsoil takes up to 1000 years.
Why is Soil Erosion Bad?
Soil erosion has a lot of harmful effects on both the environment and human life in general, including:
- Hinders agricultural growth. As topsoil is the most fertile part of the soil, its loss results in decreased crop yield. Plant roots cannot receive an adequate amount of minerals like phosphorus, resulting in rotting and death.
- Disrupts aquatic biosystems. A study conducted by the USDA concluded that the introduction of soil in lakes generally decreased the survival rate of fishes. Besides this, the mineral-rich topsoil causes eutrophication, where moss and algae flourish on the water’s surface, killing aquatic plants and affecting the entire ecosystem.
- Causes more extreme flooding. Soil-laden water from streams and lakes can clog up riverbanks and canals, causing them to overflow. This has already caused floods in countries like Colombia.
- Results in desertification. As soil erosion occurs, fewer and fewer plants grow on the land as it is not fertile enough to support its growth. It also results in a decreased capability of the soil to hold water. Over the years, previously habitable land turns into arid land like that found in the desert.
Preventing Soil Erosion During Construction
There are several things construction workers can do to help prevent soil erosion during construction.
These include phasing, carefully scheduling excavations, covering disturbed soil, using revetment structures, controlling the amount of drainage at the site, and replanting destroyed vegetation.
- Phasing. Instead of clearing large swathes of land at once, contractors should engage in phasing. During phasing, only parts of the land are cleared as the project progresses.
- Scheduled excavations. Contractors should schedule excavations on days where there will be little or no rainfall. This ensures that soil is not exposed for an extended period, and water erosion cannot occur.
- Cover disturbed soil. It doesn’t need to be covered with a tarp, you can use surrounding vegetation or mulch. This reduces displacement.
- Use revetment structures. Revetment structures are specially designed to avoid displacing soil and contributing to soil erosion. One can use articulated concrete blocks or MSE walls for land and turbidity barriers for the water.
- Control drainage in the site. It is essential to ensure that the water flow to and from the construction site is controlled through the drainage system. Otherwise, water flow could bring soil and sediment with it to the streams and ocean.
- Replanting destroyed vegetation. Grass, trees, or any plants destroyed in the construction process should be re-planted. This can be done through seeding or taking mature plants from a greenhouse.
Why Should a Contractor Take Measures to Prevent Soil Erosion?
One might say that it is a moral imperative to prevent soil erosion, but contractors and corporations don’t think that way. They consider costs in terms of time, money, and legality. However, there are a few reasons why a contractor might be interested in reducing the rate of erosion.
Contractors should take measures to prevent soil erosion not just because it’s good for the environment, but also because doing so has advantages for them. Preventing soil erosion can lead to increased productivity, less clean-up, and fewer complaints from nearby residents and city officials.
- Increased productivity. If a construction site has measures to reduce soil erosion, workers and machines are protected from the increased run-off of water caused by the soil’s inability to retain water after the topsoil layer is removed. This means less time working in mud and less bogging down of machines.
- Less cleaning up. With few erosion problems on-site, less time and money will have to be dedicated to cleaning up culverts or desilting drains. This can reduce costs by thousands on big projects.
- Fewer complaints. Residential or agricultural areas can receive silt from a construction site through muddy streams or air blowing it over. This reduces the reputation of the company and results in additional clean-up work or fines.
Despite a contractor’s best efforts, some amount of sediment will still end up being displaced. As a result, it is the state’s responsibility to have measures in place that will minimize the adverse effects of soil erosion.
Failing to implement national laws properly is a common occurrence in many countries. This can lead to shoddy work by contractors on a construction project, leading them to abandon traditional anti-erosion measures for profit.
Therefore, as a whole, construction projects can be said to increase the rate of erosion.