Water scarcity is the lack of sufficient available water resources to meet water needs within a region. It affects every continent and around 2.8 billion people around the world at least one month out of every year. More than 1.2 billion people lack access to clean drinking water.
Water scarcity involves water shortage, water stress or deficits, and water crisis. The relatively new concept of water stress is difficulty in obtaining sources of fresh water for use during a period of time; it may result in further depletion and deterioration of available water resources.Water shortages may be caused by climate change, such as altered weather-patterns (including droughts or floods), increased pollution, and increased human demand and overuse of water.The term water crisis labels a situation where the available potable, unpolluted water within a region is less than that region's demand.Two converging phenomena drive water scarcity: growing freshwater use and depletion of usable freshwater resources.
Physical water scarcity results from inadequate natural water resources to supply a region's demand, and economic water scarcity results from poor management of the sufficient available water resources. According to the United Nations Development Programme, the latter is found more often to be the cause of countries or regions experiencing water scarcity, as most countries or regions have enough water to meet household, industrial, agricultural, and environmental needs, but lack the means to provide it in an accessible manner.
Many countries and governments aim to reduce water scarcity. The UN recognizes the importance of reducing the number of people without sustainable access to clean water and sanitation. The Millennium Development Goals within the United Nations Millennium Declaration aimed by 2015 to "halve the proportion of people who are unable to reach or to afford safe drinking water.
The acute water shortage prevailing in the forest areas of Tamil Nadu's districts of Madurai and Dindigul has led to the deaths of Indian gaurs found in the forest of the region, as they come in search of water are killed falling into the wells.
With support from government and UNICEF, villagers in Palve Budruk, located in the drought-prone Parner Block in Ahmednagar district of Maharashtra, developed a catchment plan covering 1,400 hectors – over 80% of the land available. The system has three check dams, 20 canal bunds, two small percolation tanks linked to the main tank and 19 village ponds. Water stored in the percolation tank, is strictly meant for domestic use only. Piped water is supplied for an hour a day in the morning, during which time families fill up water for drinking and cooking.
SIS Seoul International School is Fundraising to bring water to India, and can be found in South Korea, or siskorea.They have also started building a strong community for the water crisis in india.
Water Resources Projects are planned for various purpose like irrigation, Hydro Power Generation, Water Supply for Drinking and industrial purpose, Flood control, navigation etc. Projects which serves more then one purpose are called as Multipurpose projects. Generally majority of multipurpose projects are combination of irrigation and Hydro-power.
A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions.
The word dam can be traced back to Middle English, and before that, from Middle Dutch, as seen in the names of many old cities.The first known appearance of dam occurs in 1165. However, there is one village, Obdam, that is already mentioned in 1120. The word seems to be related to the Greek word taphos, meaning "grave" or "grave hill". So the word should be understood as "dike from dug out earth". The names of more than 40 places (with minor changes) from the Middle Dutch era (1150–1500 CE) such as Amsterdam (founded as 'Amstelredam' in the late 12th century) and Rotterdam, also bear testimony to the use of the word in Middle Dutch at that time.
Rainwater harvesting is the accumulation and storage of rainwater for reuse on-site, rather than allowing it to run off. Rainwater can be collected from rivers or roofs, and in many places, the water collected is redirected to a deep pit (well, shaft, or borehole), a reservoir with percolation, or collected from dew or fog with nets or other tools. Its uses include water for gardens, livestock, irrigation, domestic use with proper treatment, indoor heating for houses, etc. The harvested water can also be used as drinking water, longer-term storage, and for other purposes such as groundwater recharge. Johads, one of the oldest systems used to conserve and recharge ground water, are small earthen check dams that capture and store rainwater.Constructed in an area with naturally high elevation on three sides, a storage pit is made by excavating the area, and excavated soil is used to create a wall on the fourth side. Sometimes, several johads are interconnected through deep channels, with a single outlet opening into a river or stream nearby. This prevents structural damage to the water pits that are also called madakas in Karnataka and pemghara in Odisha.
Rainwater harvesting is one of the simplest and oldest methods of self-supply of water for households usually financed by the user.Rainwater harvesting provides an independent water supply during regional water restrictions, and in developed countries, is often used to supplement the main supply. It provides water when a drought occurs, can help mitigate flooding of low-lying areas, and reduces demand on wells which may enable groundwater levels to be sustained. It also helps in the availability of potable water, as rainwater is substantially free of salinity and other salts. Application of rainwater harvesting in urban water system provides a substantial benefit for both water supply and wastewater subsystems by reducing the need for clean water in water distribution system, less generated stormwater in sewer system,and a reduction in stormwater runoff polluting freshwater bodies.
A large body of work has focused on the development of lifecycle assessment and lifecycle costing methodologies to assess the level of environmental impacts and money that can be saved by implementing rainwater harvesting systems.
Rainwater Harvesting in India:-
1.Khadins and Johads:-
Khadins are ingenious constructions designed to harvest surface runoff water for agriculture. The main feature of a khadin, also called dhora, is a long earthen embankment that is built across the hill slopes of gravelly uplands. Sluices and spillways allow the excess water to drain off and the water-saturated land is then used for crop production. First designed by the Paliwal Brahmins of Jaisalmer in the 15th century, this system is very similar to the irrigation methods of the people of ancient.
Johads, one of the oldest systems used to conserve and recharge ground water, are small earthen check dams that capture and store rainwater.Constructed in an area with naturally high elevation on three sides, a storage pit is made by excavating the area, and excavated soil is used to create a wall on the fourth side. Sometimes, several johads are interconnected through deep channels, with a single outlet opening into a river or stream nearby. This prevents structural damage to the water pits that are also called madakas in Karnataka and pemghara in Odisha.
It is practice in arid and semiarid regions of rajasthan and gujrat.
1.Rainwater falling on the roof is collected through PVC pipes.
2.The collected water filtered by passing it through a layer of sand and bricks.
3.The filtered water then collected in sump or where water is collected.
4.Excess water in the sump is then collected in the well that get recharge with fresh water.