Water always finds a way out. -Old proverb of Cameroon
In my earlier post I spoke about Blue Water. Blue Water is also called horizontal water because it is the water that we see flowing on earth in an almost horizontal direction. It is also the visible water. There is however an unseen part of water, unseen but moving in the vertical direction. This water is known as vertical water or Green Water.
Traditionally our approach towards freshwater resources remained centered only on specific aspects, aspects concerning the visible water while overlooking aspects that are equally or even more important for human development. For example when we talk about the quality of freshwater, we mostly find pollution as relevant. There is thus the invisibility of freshwater and related eco-system services that are quite important with respect to direct freshwater services. Entire pollution debate seems to be around how human health is going to be affected as if eco-systems can tolerate pollution indefinitely.
Green Water is the invisible part of water that keeps the soil moist, flows through the root systems of plants to make up cellulose and exists in the unseen evapo-traspiration of the plant world plus the constant evaporation of water from extensive water bodies like oceans, lakes, rivers, wetlands etc. If you refer to my post titled “Water Paradox: An approach to understand Water Crisis”, you may see that I have mentioned about 113,000 cubic kilometers of unseen Green Water contained in soil moisture and atmosphere. This part of the water balance does not popularly figure in our water discourses because we do not see this water or rather do not extract water from these reservoirs. There is, however, no reason why we should not bring this water into our active debate and consideration. Green Water is what sustains non-irrigated plants, including forests and woodlands, grasslands and rain-fed crops.
There is another very good reason for us to be concerned about the Green Water. A part of Green Water exists in the atmosphere as water vapor which is the largest green house gas so any large scale change in its absolute magnitude or distribution has a direct impact on warming/cooling of earth surface and ultimately related to Climate Change.
Green Water balance impacts humanity more globally and long term than Blue Water Balance. We can fight and survive draughts and floods, albeit with hardship. But if our actions interfere with the Green Water flow and balance, the resultant stress has the potential to get out of control or survival capacity. For example think about and try to imagine the impact in the following scenarios (all concerning disturbing Green Water flow or balance).
1. Deforestation. No evapo-transpiration and the soil moisture and water vapor tend to transfer to Blue Water reserve.
2. Large-scale black topping. No evaporation from soil and the soil moisture tend to transfer to ground water.
3. Over-irrigation. Abnormal evaporative surface and Blue Water tends to transfer to Green Water.
The hydrological cycle of earth is meant to store and maintain the water reservoirs in a specific way for the Global Weather and Climatic engine to function normally. If our actions disturb that balance we can never manage the Water Crisis effectively.
[Image Credit: Stan Kaufman]
[Feature Image Credit: otoinclus.com ]