Water stress is most vivid in\" megacities\", do you agree or disagree with this
ID: 117158 • Letter: W
Question
Water stress is most vivid in" megacities", do you agree or disagree with this statement. Why do you say this? Explain the ways in which they contribute or not to the stress. Your explanation should be coupled with at least one real world example such as Mexico City, Mumbai, Tokyo, Lagos, etc.
Irrigation is on an ecologist's hit list. Why? Discuss pros and cons for irrigation of an agricultural land. In your opinion what can be done in the future in this sector of water resources management (give at least 3 suggestions). At least one real world example (irrigated land) should be part of your discussion.
Explanation / Answer
In this modern world, water demand is at its all time high !! It is a vital resource for all living lives in this planet. However we know that less than 1% of the total water volume is potable (in froms of rivers, lakes and groundwater etc). If we compare the volume of potable water in comparison to lakes, rivers and groundwater, the groundwater is the largest reservoir of potable water in the world. Due to population growth especially in megacities like Mumbai, India, potable water is becoming scarcer to feed its population of 21 million people. As a coastal city, Mumbai has an additional hazard, known as Salt water intrusion. This takes place when the hyraulic head of the aquifer becomes lesser than that of sea water. The hydraulic head decreases due to over exploitation of the aquifer, hence the "potable" becomes salty. Mumbai's rapid expansion has lead to the disappearance of lakes and rivers have become polluted due to improper waste disposal. Yes, Mumbai's aquifers gets recharged during the South West Monsoon, but that it is not enough to feed its entire population. Hence a mega city like Mumbai do suffer water stress and could become harder and harder for its population to depend on its freshwater reservoirs.
The main reason for irrigation to be on an ecologist's hitlist is that the process consumes groundwater at an alarming rate and if the land becomes saline due to sea water intrusion, no further activities can take place on that piece of land.
The pros of irrigation include
The cons of irrigation include
In the Indian Province of Uttar Pradesh, irrigation is the main profession for the majority of the population. The province has a population of 200 million, hence water stress is even higher if you also consider the seasonal rainfall and the flow of mighty river such as the Ganges and the Yamuna. The water requirements for the irrigation is very high. Hence there are some projects which check the water intake for irrigation.
Comparatively larger net rainfed areas exist in thehills (mostly Uttaranchal and Bundelkhand) because of the sheer impracticability of irrigating higher lands, much above the valley floor, either on hill slopes or on plateaus. Even in the Eastern region, the south of the Ganga area in Sone and Tons sub-basins is somewhat similar in topography to Bundelkhand, and hence a larger net rainfed area is projected. Hence these areas will have a more net irrigated area than the other parts of the province. Hence this type of planning is dependent squarely on the rainfall the province receives.
The net irrigated area is getting limited, Significant area will remain under the long duration sugarcane crop, hot weather crops between rabi and kharif are unlikely to grow in a large way, both due to social factors and non availability of water in this lean season.These will make larger irrigated area impracticable. These steps are taking intom consideration of different types of crops which would grow in different parts of the region.
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