i. (a) Water is an elixir of life, a very important natural resource. Your Science teacher wants you to prepare a plan for a formative assessment activity, “How to save water, the vital natural resource”. Write any two ways that you will suggest to bring awareness in your neighbourhood, on ‘how to save water.’

(b) Name and explain any one way by which the underground water table does not go down further.

ii. Explain two main advantages associated with water harvesting at the community level.

a. As with all of Nature it is a symbiotic factor in a greater whole, and an element all life depends on. As we degrade our soils, poison our land and remove the natural catchments for runoff through deforestation and removal of trees; as we fill in our waterways and natural filtering systems in the name of development and progress; as we dam up rivers destroying natural eco-systems, we completely upset the natural scheme of things that water needs to flow and filter clean water for us all.

Two ways of creating awareness are:

• Door to door campaigning.

• Nukkad natak/any other methods.

• Check for leaking pipes and faulty taps in your neighbourhood.

• Introduce rainwater harvesting systems.

• Work as a community with social groups and NGO’s.

b. Groundwater is the water present beneath Earth's surface in soil pore spaces and in the fractures of rock formations.

Water scarcity, including depleting levels of ground water is a subset of problems associated with climate change and unfortunately both of them are global man-made disasters. To overcome this problem, huge investments in infrastructure as well as institutions are required. As serious as it may sound, there still is time to repair the damage done.

These are some ways in which we can maintain underground water table:

• Water in flood hit areas or areas with water adequacy can be channelized underground using some form of innovative designs to replenish aquifers. This water can be used up during dry seasons using the age old tube well mechanism.

• Rain water harvesting should be extensively adopted wherever possible.

• Remote sensing should be incorporated across multiple platforms. It has become easier to predict now, where and up to what extent flood or drought will strike. Using remote sensing data, the levels of underground water can also be judged remotely. This data can be transmitted to local bodies and farmers so that the use of water can be better planned. Mobile applications can play a key role here in transmitting data. If farmers already know that they are going to get less water for a particular harvest cycle, they can sow crops which require less water like oil seeds or pulses. The entire process is not high on investment and is easy to incorporate.

• Drip irrigation requires 35-40% less water than flood irrigationonly with a small investment. Government plans to boost drip irrigation will help lower water scarcity.

• Reduction of unnecessary water usage on the industrial scale needs to be monitored. The release of effluents and toxic chemicals in water is being monitored well, but a mechanism to check the usage of water in the first place needs to be re-looked.

• Processes that turn salt water to fresh water such as Desalination and Per-vaporization are high on energy demands and hence cost making them unfeasible. Some innovation in the plant design or energy savings such that these processes can become feasible will help boost the production of fresh water.

• And most importantly: awareness about using water judicially needs to be there. Awareness leads to curiosity which further leads to science.

ii. Water harvesting is the collection of runoff for productive purposes. Instead of runoff being left to cause erosion, it is harvested and utilized. In the semi-arid drought-prone areas where it is already practised, water harvesting is a directly productive form of soil and water conservation.

Advantages of water harvesting at the community level are as below

• Water harvesting improves the quality of ground water. There stored water provides moisture and helps in improving vegetation in and around the area. It also prevents soil erosion, floods.

• Water harvesting in rural areas not only increases the agricultural production but also increases the life of downstream dams and reservoirs.

• Ground water generally does not get polluted, if it is away (at least 20 mtr.) from the sanitary works. The water gets filtered while percolating through sand & stones. Therefore groundwater remains pure and clean.

• Since bore well is closed, no risk of getting contaminated.

• Since it is closed no danger of children or animals falling into it.

• Temperature of deep water remains stable. It feels cool in summer and warm in winter.

• Since bore are deep, chances of water remaining available in summer are more.