The 100+ year old well at the Hyderabad Collective in Bodakonda, Telangana

Water, the life-giving element, holds more secrets than you might think. It is naturally available on landscapes in various forms. Be it in the form of underground water (a chief source in dry & arid regions like the Hyderabad Collective), or through rivers originating from high points such as mountain glaciers or high altitude natural reservoirs (such as the Shola grasslands in Southern India present in the Poomaale Collective in Coorg), water displays a wide array of colours that signal its health, purity and the kind of environment it has flown through. In this blog, we shall explore the colours of this apparent colourless element – from the deep blues of the ocean to the shimmering clarity of shallow streams.

Water – A Colourless Element?

Water is often described as a colourless element, and this is generally true in its purest form, which is, in the absence of impurities and suspended particles. However, when light comes to play, water seems to show more colours. When water contains impurities, dissolved substances, or suspended particles, it can take on various colours. The green-blue sea, the blue of pristine pools, and the golden brown hues during the sunset – all these are various colours that water displays during its interplay with light. 

Why Does Water Appear Blue?

The formation of colour is a wonderful phenomenon. The colours we see are results of the wavelengths that are reflected back to our eyes. It applies to all living matter, from the colours of leaves, to the colours of fruits & vegetables. Similarly, water appears to have a distinct blue colour due to its selective absorption and scattering of sunlight. Water molecules have a tendency to absorb longer wavelengths of light, particularly in the red and yellow parts of the visible spectrum. The shorter wavelengths of light, such as blue and green, are scattered less and are therefore more likely to be reflected back to our eyes. This scattering and reflection of blue and green light are what give water its blue colour. This phenomenon is what gives bodies of water like oceans, lakes, and rivers their serene hues.

The depth of water also plays a role in the perception of its colour. Deep water, such as that of oceans, looks blue because sunlight goes deep into the water and gets rid of the longer wavelength  colours. It keeps the blue and green colours. Shallow water, such as that of pools or smaller river streams, appears clear because there’s not as much water for sunlight to go through. You can see the bottom or any dirt in the water more easily. 

But, we do find murky or green waters in different ecological habitats. So what other colours can water embody, and what do various colours of water indicate?

Colours of Water – Clues for Building Ecosystem Knowledge

Naturally occurring water can display a range of colours other than blue, and these colours are often indicative of specific conditions or substances present in the water. Below are some of the other colours that water can display and what they may indicate.

Green

• Indicates the presence of algae which contains the green colour inducing chlorophyll. 
• Common in stagnant or nutrient-rich bodies of water and can be a sign of eutrophication, a process where excess nutrients lead to increased algal growth.

Brown or Yellow

• Typically due to the presence of organic matter or suspended particles. 
• Can be caused by decaying leaves, soil runoff, or pollution.

Red or Brownish-Red

• Can indicate the presence of iron or iron bacteria which can oxidise and form iron oxides, giving the water a rusty colour.

Cloudy or Turbid (Gray or White)

• Often a result of suspended sediments or fine particles in the water which can scatter and reflect light, making the water appear cloudy or milky. 
• High turbidity can be caused by erosion, construction activity, or the resuspension of sediment from the bottom of a water body.

Brown

• Can indicate the presence of organic matter.
• The murkiness can be caused due to soil erosion during the course water takes.

Black

• Typically an indication of high levels of dissolved organic material. 
• May also indicate polluted waters due to industrial discharges.

Pink or Reddish-Pink

• Can indicate the presence of certain types of bacteria or algae, producing pigments that colour the water. 
• Pink lakes, like Lake Hillier in Australia, are famous for their striking pink colour, which is attributed to a specific type of pink-coloured algae.

Blue-Green

• Besides the scattering of blue and green wavelengths, the blue-green colour can indicate the presence of cyanobacteria (blue-green algae). 
• These bacteria can produce various pigments, and their presence can be an indicator of water pollution and potential harm to aquatic life and human health due to the toxins they release.

It’s essential to note that the colour of water can change over time and can vary depending on environmental conditions, such as season, weather, and location. Additionally, human activities and pollution can significantly alter the natural colour of water and may lead to undesirable water quality issues. 

Why is the Knowledge of Colours of Water Important?

As Consumers, understanding the various colours of water in natural bodies is essential as it can indicate the health and safety of the environment. Different water colours can signify pollution, algal blooms, or the presence of harmful substances. Being aware of these changes can help individuals make informed decisions about recreational activities, drinking water sources, and environmental conservation efforts. It also empowers consumers to advocate for water quality and raise awareness of potential issues.

As landscape developers with focus on soil regeneration, water is our lifeblood. Working with natural bodies and landscapes, knowledge of water colours is vital for the responsible and sustainable development we have started to make. The colour of water and condition of water at our collectives is a reflection of its quality and suitability for particular functions. Being attuned to these changes enables us to make informed decisions about site selection, landscaping choices, and water management. It allows for the design of eco-friendly landscapes that harmonise with the natural environment and help maintain water quality, benefiting people as well as the Earth. Additionally, being aware of these colour shifts in water can help us detect and mitigate potential issues, ensuring the long-term success of our 100+ acre landscape regeneration projects.