Deforestation refers to the destruction of forests for purposes such as lumber production, agriculture (such as coffee or corn crops) or extraction (like mining oil and gas extraction). By cutting down forests for such purposes, deforestation removes trees that provide essential services like pulling carbon dioxide out of the atmosphere while contributing to water cycle regulation and helping the water cycle function properly.
Researchers studied satellite images, microsurvey data and population statistics to discover that every decade of deforestation in Malawi decreases access to clean drinking water by one percentage point – equivalent to having almost one tenth less rainfall!
Water Cycle
Forests play an essential role in maintaining global water supplies through an intricate water cycle, and play an indispensable role in managing their quality, quantity, cost and use by mitigating flooding risks and drought effects, controlling erosion rates and decreasing pollution entering lakes rivers and streams.
Deforestation alters this balance by decreasing rainfall and increasing runoff, potentially leading to floods, droughts, soil erosion and contamination with harmful heavy metals such as mercury, cadmium and lead contaminating water resources. This process also alters biodiversity.
Lack of rainfall and increased runoff lead to sand and silt flowing downstream, decreasing access to clean drinking water for households. According to one study, each one percent reduction in forest cover decreased access by 0.93 percentage points – thus impacting availability of clean drinking water for every household in America.
Deforestation increases water flows through surface channels by speeding evaporation; thus resulting in less available to drink through streamflows. Trees help slow the flow by absorbing rainwater into their roots, which reduces streamflow. Conversely, trees help slow the flow by soaking it up through their roots into their roots, thus decreasing streamflow. This creates an ironic result as less rainwater is available for consumption as a result of deforestation resulting in higher streamflow volumes than otherwise available through trees absorbing raindrops becoming available through surface channels due to faster evaporation rates which means less available water is available through streams reducing streamflow but ultimately less water is available as more people opt out to drink this source!
As forests are deforested, more sources of pollution arise downstream; for instance agribusinesses, mining companies and logging operations that operate in forests. Their activities pollute waters with chemicals and pathogens that can have serious health repercussions for those who consume their waters.
Loss of trees increases the risk of flooding and landslides, which in turn can pollute freshwater sources with harmful metals and chemicals that eroded soil will transport via rivers and streams into inland bodies of water. This pollutant could include toxic metals used for industry as well as other chemicals which pollute freshwater supplies such as lakes.
Pollutants found in water threaten human and environmental health, as well as cause higher costs for companies using polluted water in production processes, like Danone which lost EUR740,000 due to contamination at its Brazil facilities when river water entered their supply chains contaminated. As a result, companies such as Danone are taking measures such as protecting and restoring forests within their supply chains to preserve clean water sources while building resilience against climate change; their efforts are supported by investors like Norway’s largest sovereign wealth fund who have set a goal to disclose deforestation/water security policies by 2020 for all 4,600+ companies within their investment portfolios – both initiatives have goals set to keep these initiatives on track with regard to deforestation/security actions taken within each company in their supply chains.
Soil Erosion
Soil erosion is a natural process caused by wind, water currents and gravity pulling away soil particles, but can be hastened by human activities like clear-cutting. Not only does soil erosion devastate ecosystems but can also degrade water quality by polluting it with toxic chemicals contaminated soil particles which eventually find their way into rivers and waterways causing blockages or flooding.
Erosion also contributes to water contamination by increasing sediment and turbidity, decreasing water quality and making treatment for homes and businesses harder. Although exact numbers on how much soil erosion occurs globally are difficult to ascertain, most scientists believe human activities account for two-thirds of global erosion.
Studies have demonstrated that deforestation significantly decreases the amount of rainwater that infiltrates soil, increasing runoff and erosion that impacts rivers and streams, ultimately decreasing available water for human use and economic development. This can have negative repercussions for human health as well as economic growth.
Deforestation is one of the primary contributors to global soil erosion. It can result from both natural and human factors; for example, tree felling for timber production or expanding agricultural lands for oil palm cultivation are major sources of deforestation, while climate change can increase erosion by decreasing rainfall or increasing winds.
Hisahiro Naito and Annie Mwayi Mapulanga conducted a groundbreaking study that linked satellite data quantifying forest cover loss in Malawi with household drinking-water access statistics in Malawi. As a result, 0.93 percent fewer households would have safe drinking water for every percentage point loss in forests.
Soil erosion can be caused by several factors, including climate, terrain, aggregation and the type of crop grown. Erosion tends to occur more quickly during severe weather events or with machinery used for farming or conventional irrigation – both can dislodge soil quickly enough that floodwaters carry it away quickly – while overgrazing makes bare fields even more vulnerable.
Flooding
Deforestation directly impacts water resources of an area and can cause flooding disasters that kill many people and destroy homes and crops, as well as cost billions annually in financial losses. As this issue has become so serious, it has even been included within the 2030 Sustainable Development Goals.
Studies have linked deforestation and flooding together. Trees act to slow the flow of water by absorbing it; when they’re cut down, this process accelerates and floods are much more frequent; one study found that every 10% increase in deforestation raises flood risks by 28 percent.
Deforestation not only stymies the water flow, but it can also result in erosion that reduces soil quality and leads to the release of stored ground and aquifer water; consequently reducing available drinking water supplies.
Deforestation has another negative impact on clean water sources in that it alters the morphology of river basins, which can have particular ramifications in flood-prone flat areas. Furthermore, deforestation lowers hill and mountain elevations which makes it harder for water to move downhill preventing flooding events from taking place.
Deforestation also reduces precipitation levels; trees play a pivotal role in helping transform liquid into air through evaporation, with leaves and roots taking in ground water, storing it within their tissues before dissipating into the atmosphere through their leaves and roots. When trees are lost this process is disrupted and much needed moisture evaporates away into thin air – meaning we lose water as precipitation!
Recent research in Malawi demonstrated that just 10 years of deforestation could decrease access to clean water by an equivalent of 9 percent less rainfall, suggesting we need to preserve forests and reforest areas that had previously been deforested. This is an alarming realization and underscores why protecting and replanting areas that have previously been cleared is so vitally important.
Water Quality
Destruction of trees causes disruptions to the water cycle and erosion of soils, leading to increased sediment and turbidity levels in streams, rivers and lakes resulting in decreased drinking water quality as well as higher costs associated with treatment processes.
Deforestation leads to reduced rainfall levels in an area, which in turn affects its ability to provide clean drinking water to its inhabitants. This may lead to water shortages which threaten both their health and well-being in affected communities.
As previously discussed, trees are essential in maintaining high-quality water by soaking up rainwater through their roots and reducing runoff rates. Without trees, water flows more quickly through soil layers with reduced infiltration rates and an increase in runoff speeds that could cause flooding concerns as well as higher concentrations of pollutants being transported into nearby sources.
The TERENO study in Malawi discovered that when forest cover decreased by just 1 percent, access to piped water at public taps and use of unprotected wells as sources of drinking water decreased proportionately. Researchers also observed an increase of 0.59 percentage points for every increase in forest area/land area ratio.
Water quality can be defined as the concentration of organic and inorganic substances – such as metals, nutrients, hydrocarbons and others – present in a sample of water. Aesthetic characteristics like colour, odour, taste and turbidity also help determine its quality; recent studies have demonstrated this. Undisturbed forest waters often boast excellent water quality.
Numerous companies are taking steps to decrease their impact on forests around the world and protect and restore local clean water sources, setting an example for others that it is possible for businesses to be both socially responsible and financially sound by investing in protecting environmental resources; some are even committing to deforestation-free supply chains and reporting progress with CDP.
