The Origin Of Water: Sources And Mystery

Water is a precious natural resource, covering nearly two-thirds of the Earth's surface. All living organisms, including humans, animals, and plants, need water to survive. Water is used for drinking, cooking, washing, and industrial purposes. The primary sources of water are surface water and groundwater, with surface water being the main form, including rivers, streams, lakes, and ponds. Groundwater is located below the surface of the Earth in spaces between rocks and soil. These water sources are vulnerable to contamination, and protection efforts are essential to maintaining water quality and quantity for communities. Rainwater collection is another essential water source, although on a smaller scale.

Groundwater

The area where water fills the aquifer is called the saturated zone (or saturation zone). The top of this zone is called the water table, which may be located only a foot below the ground’s surface or it can sit hundreds of feet down. The speed at which groundwater flows depends on the size of the spaces in the soil or rock and how well the spaces are connected. Groundwater is typically recharged from the surface through precipitation and seepage from surface water. However, recharge can also be done intentionally by diverting water to engineered infiltration ponds, spreading basins, flooding of agricultural lands, and injection wells.

Surface water

There are three primary types of surface water. Firstly, permanent (perennial) surface waters are present year-round and include lakes, rivers, and wetlands (marshes and swamps). Secondly, semi-permanent (ephemeral) surface water refers to bodies of water that are only present at certain times of the year, such as seasonally dry channels, creeks, lagoons, and waterholes. Lastly, human-made surface water is created by human-assembled infrastructure, such as dammed artificial lakes, canals, and artificial ponds or swamps.

To address the challenges posed by water quality and availability, organisations like the US Environmental Protection Agency (EPA) and the US Geological Survey (USGS) implement various programs and research activities. For instance, the EPA's Source Water Protection (SWP) program aims to prevent the contamination of drinking water sources, while the USGS's California Water Science Center monitors surface water and studies water quality and aquatic habitats. These efforts are crucial for maintaining sustainable aquatic life and ensuring safe drinking water for communities.

Rainwater

While rainwater is a valuable resource, it can be affected by air contamination, which can cause it to become acidic and cloudy, and introduce heavy metals such as lead (Pb). Lead exposure has been linked to various adverse health effects, including kidney disease, cancer, and cognitive impairment. Therefore, it is essential to test rainwater for germs and chemicals regularly to ensure it is safe for consumption.

To address the issue of lead contamination in rainwater, treatment methods such as filtration and absorption have been developed. For example, a study in West Kalimantan utilized mollusk sand and activated carbon to effectively filter polluted rainwater, making it safe for drinking.

Overall, rainwater is a valuable water source, especially in regions with limited access to other water resources. By implementing effective collection and treatment methods, communities can utilize rainwater as a sustainable and safe source of water.

Water treatment and purification

Water Treatment Processes

Water treatment plants employ various methods to purify and improve water quality, including:

• Coagulation: Chemicals are added to the water to help bind together dirt and other small particles, making them easier to remove.
• Flocculation: The water is gently mixed to form larger, heavier particles called flocs, which can then be separated through sedimentation or filtration.
• Sedimentation: This process allows solids and suspended particles to settle out of the water by gravity, leaving clearer water on top.
• Filtration: The clear water is passed through filters made of materials like sand, gravel, or charcoal to remove germs, parasites, bacteria, viruses, and dissolved particles such as dust and chemicals.
• Disinfection: Chemical disinfectants, ultraviolet (UV) light, or ozone are used to kill any remaining germs, ensuring the water is safe for human consumption.
• PH Adjustment: The pH of the water is adjusted to improve taste, reduce pipe corrosion, and enhance the effectiveness of chemical disinfectants.

Water Reuse and Sustainability

Water treatment plays a critical role in sustainable resource management. By enabling water reclamation and reuse, treatment processes reduce the strain on limited freshwater sources, especially in water-stressed regions. Treated wastewater, also known as reclaimed water, is an important artificial source of freshwater. Additionally, water treatment plants can produce energy through methane generation from sludge treatment and create natural fertilizers from biodegradable materials in wastewater.

Protecting Water Sources

Protecting water sources, such as rivers, streams, lakes, reservoirs, springs, and groundwater, is crucial to reducing contamination risks and treatment costs. The US Environmental Protection Agency (EPA) works with various stakeholders to implement programs that maintain drinking water quality and protect source water from natural and human-made threats. The Safe Drinking Water Act (SDWA) is a key component of these efforts, promoting a "multi-barrier approach" to safeguard drinking water sources and public health.

Water scarcity

Agricultural practices contribute significantly to water scarcity. Agriculture accounts for 72% of all water withdrawals, and inefficient irrigation systems, application methods, and water-intensive crop choices result in significant water waste. Pesticides and fertilizers also contaminate water sources, rendering them unfit for human use.

Addressing water scarcity requires an integrated and inclusive approach that considers the specific contexts and needs of different communities. UNICEF, for example, works at multiple levels to introduce context-specific technologies that increase access to safe water. This includes improving water efficiency, planning for urban scarcity, expanding climate-resilient water sources, advancing water storage, and promoting behavioural changes that emphasize the value and protection of water.

Frequently asked questions