Rain Water Harvesting Interview Questions & Answers

Rain Water Harvesting Interview Questions

Are you a person willing to work in rain water harvesting programs? Are you a person with a degree in Civil engineering or Environmental engineering then logon to www.wisdomjobs.com. Rain water harvesting is a technique used for collecting, storing and using rainwater for landscape, irrigation and other uses. Rain water is collected from various hard surfaces such as roof tops and other man-made above ground surfaces . This practice is growing in popularity due to interest in reducing the consumption of potable water and the inherent qualities of rainwater. It is water conservation option. Water is collected from the roof tops of buildings and stored in rainwater tanks. So trace yourself as Site engineer, Design engineer, Associate Manager, Organic Harvesting Operator Farm Operator , Hand Harvester by looking into Rainwater harvesting job interview question and answers given.

Rain Water Harvesting Interview Questions And Answers

Rain Water Harvesting Interview Questions
    1. Question 1. What Is Rain Water Harvesting?

      Answer :

      Rain water harvesting means collecting and storing rain fall (precipitation) at or near the location where it falls.

    2. Question 2. What Is The Purpose Of Rain Water Harvesting?

      Answer :

      The purpose of rain water harvesting is to use rainfall as a source of water.

    3. Question 3. Where Is The Water Stored?

      Answer :

      Water is stored either in specially constructed tanks or in a subsoil/Aquifer or at both the places.

    4. Question 4. What Does It Cost To Store Rain Water?

      Answer :

      The cost of collecting rain water in a storage tank depends on the type of structure, location, capacity and other parameters. generally, the cost varies from Re.0.50/- to Rs. 10.00/- per a liter.

    5. Question 5. What Are The Different Structures Used For Rain Water Harvesting??

      Answer :

      Following are the various types of structures used for storing rainfall:

      • Stone work tank
      • Brick work tank.
      • R.C.C. Tank
      • Ferro cement tank.
      • Pond.
      • Polyethylene sheet lined pond.
      • Coconut fiber cement tank.
      • Loose Stone bandhare.
      • Soil bandhare
      • R.C.C./Stone Bandhare

      Following are the options / methods for collecting / storing rainfall in subsoil / aquifer :

      • Percolation trench.
      • Percolation pit.
      • Percolation trench with bore.
      • Percolation pit with bore.
      • Percolation pond.
      • Vanarai bandhara.
      • Loose stone bandhara
      • Soil bandhara..
      • Dugout sunken pond
      • Subsurface dam.
      • Structures developed with the help of methods / options from(f) to (j) store water for few days to few months. Hence they areused both for storage and for recharge.

    6. Question 6. Is Rain Water Safe For Drinking?

      Answer :

      • Properly stored "Roof Top Rain Water" can be used for drinking provided the following care is taken.
      • Rain water stored should not be exposed to sun.
      • No exposure to atmosphere.
      • Ferro cement tank.
      • It is also advisable that water be disinfected through chlorination before using it for drinking.

    7. Question 7. How Can Rain Water Harvesting Be Useful For Agriculture?

      Answer :

      A portion of agricultural land (farm land) is used for storing water, will depend upon quantity of water required for farming / horticulture etc.

    8. Question 8. Is It Possible To Use Rain Water For Industrial Purpose?

      Answer :

      It is possible to use rooftop rainwater for industrial purpose after proper filtration (treatment). Run off rain water can also be collected in pond and then can be used for industrial purpose after proper treatment.

    9. Question 9. Can Rain Water Replace Water Supply For Public Utility?

      Answer :

      Rain Water can replace water Supply in City, but to what extent will depend on the following. (at the least, it can meet a part of the water requirement of a city):

      • Annual average rain fall.
      • Density of population.
      • Ferro cement tank.
      • Geology and hydro geology of that area and many other factors.

    10. Question 10. How Much Spaces Is Required To Collect Rain Water?

      Answer :

      It depends on the extent to which you desire to use rain water.Assuming normal conditions, around 5% to 10 % area is Sufficient to utilize most of the rain fall during the monsoon period or through the whole year.

    11. Question 11. Who Can Practice Rwh?

      Answer :

      You, me and everybody! It will not only provide you with water in times of acute water shortage, but will also recharge the groundwater and increase its level.

    12. Question 12. Why Should I Implement Rwh?

      Answer :

      Rainwater is the ultimate source of all the fresh water that we use. In India, rainfall occurs in short periods of high intensity, allowing the rain falling on the surface to flow away fast. This leaves little scope for recharging the groundwater, which results in water scarcity in most parts of the country. Through RWH, this erratic rainfall can be conserved, stored & used as per convenience, either directly or for recharging groundwater.

    13. Question 13. Where Can Rwh Be Implemented?

      Answer :

      RWH can be done in homes, apartments, societies, schools, institutions, commercial premises and any other space as long as there is a catchment area in the form of a roof or open space to capture the rain.

      Domestic rainwater harvesting is a relatively simpler affair, where even a rain barrel can serve as a storage unit for rooftop RWH. Individual homes have successfully implemented this easy and eco-friendly method of augmenting household-level water availability. Farmers also have implemented RWH to transform a barren piece of land into a self sustainable, lush green farm.

    14. Question 14. Is Rwh Only Feasible For New Buildings?

      Answer :

      No, existing buildings can also implement RWH by modifying the existing plumbing and making additions, if necessary.

    15. Question 15. What Quantity Of Rainwater Can Be Collected?

      Answer :

      The rainwater harvested depends upon the catchment area, the rainfall pattern in the area and the drianage/ collection system used. 

      To understand the potential for rainwater harvesting, lets take the example of a house in Delhi with a terrace area of 100 sqm. Taking the average annual rainfall in Delhi as 600 mm, and assuming 70% harvesting efficiency (as some rainwater will be lost due to evaporation, collection etc.),

      we can calculate the amount of water harvested thus:

      Volume of water harvested = 100 x 0.6 x 0.7=42,000litres

      This volume is more than twice the annual drinking water requirement of a 5-member family, whose average daily drinking water requirement is 10 lpcd.

    16. Question 16. What Is The Cost Involved?

      Answer :

      The cost will vary depending upon the catchment area and the conveyance/ storage structures finalised. RWH can be installed at a very low cost in large plots where public buildings, schools & colleges are located, and this cost is negligible to the total construction cost, if integrated with the building design.

      If planned in an existing building, the cost is higher due to extra plumbing involved, but the returns are rich in terms of recurring benefits. 

    17. Question 17. What Types Of Filters Are Needed For Rwh? Which Type Is Needed If The Rainwater Is To Be Used For Flushing Toilets?

      Answer :

      Various kinds of filters are used in RWH. If the rainwater is to be used for flushing toilets alone, there is no need for any filter but the roof needs to be kept reasonably clean. If necessary, a grating can be fixed at the inlet point to the loft from the roof.

    18. Question 18. Can The Stored Rainwater In Storage Tanks Be Used For Cooking And Drinking?

      Answer :

      The rainwater that falls on the roof is pure, but since it comes in contact with various surfaces on its way to the storage units, some dust and leaves may get carried away with it. This can be reduced if the terrace is swept before the rains. However, even if some dust or leaves go into the sump, they do not cause any harm as long as the water is boiled before consumption.

      Various filters can be utilised to remove such suspended pollutants from the rainwater collected to make it safer for consumption.

    19. Question 19. What Are The Various Types Of Rwh?

      Answer :

      Rainwater harvesting can broadly be divided into 3 categories based on the types of usage, the area in which harvesting is carried out and the people involved.

      Storage or recharge: Based on the type of usage, structures can either be used to store the collected water for direct use or to recharge groundwater.

      Urban-rural difference: Urbanization has resulted in the shrinking of open spaces as well as unpaved areas. This has resulted not only in flooding of cities but has also caused water scarcity due to groundwater depletion in general and saline water intrusion in coastal cities. While rural harvesting is mostly traditional and is carried out in surface storage bodies like rivers, tanks, ponds, lakes etc., urban harvesting, due to lack of open space for capturing the runoff, is mostly in sub-soil storage as groundwater recharge.

      Rooftop & driveway harvesting: When we say rainwater harvesting, the first thing that comes to our mind is the terrace. This greatly restricts the scope of rainwater harvesting as a considerable amount of water that falls around the built-up area is let out of the building as run-off. Driveway run-off water should not be led into a sump for immediate use or to a source well, but it can very well be directed into recharge wells.

    20. Question 20. What Are The Basic Components Of A Rwh And Conservation System?

      Answer :

      1. Catchment areas that include roofs of buildings and open spaces.
      2. Storage units that can be a barrel, a tank or even a sump.
      3. Conveyance mechanism which transports the water falling on the catchment area to the storage unit.

    21. Question 21. What Are The Characteristics Of A Good Rwh System?

      Answer :

      The RWH system must ensure that not a drop of rainwater falling within the premises is let into the sewerage or wasted as runoff.

      This can be achieved only if the method adopted within the premises satisfies the following criteria:

      Completeness: Both rooftop and driveway runoff water must be harvested.

      Apportioning of water: To avoid overload of any one system, leading to overflow and loss.

      Proper design: Volume of water likely to flow through and the nature of the soil in the area should be considered.

      Maintainability: Design should incorporate features allowing for periodic maintenance of the structure.

    22. Question 22. Can Existing Structures Be Used For Rwh?

      Answer :

      Existing unused structures like dried open wells, sumps etc can be used for RWH as also defunct borewells, instead of constructing recharge structures. This will also reduce the total cost.

    23. Question 23. What Does Artificial Recharge To Groundwater Mean?

      Answer :

      It is a process by which the groundwater is augmented at a rate exceeding that obtained under natural conditions of replenishment. Any man made scheme or facility that adds water to an aquifer may be considered to be an artificial recharge system.

    24. Question 24. What Are The Various Types Of Recharge Structures ?

      Answer :

      Recharge structures are constructed to allow rainwater to replenish groundwater.

      The various ways in which recharge can be done is through:

      • Abandoned dugwell
      • Handpump
      • Recharge pit
      • Recharge trench
      • Gravity head recharge tubewell
      • Recharge shaft

    25. Question 25. What Is A Recharge Pit? Is It The Same As A Recharge Well?

      Answer :

      A recharge pit is a hole dug in the ground, usually filled with gravel or jelly to give it structural strength. However, a recharge well is not filled with gravel, but needs concrete rings installed in it to stabilise its walls.

    26. Question 26. What Should Be The Depth Of A Recharge Well/pit?

      Answer :

      For effective recharge in Bangalore like conditions, a 15-20 feet depth is needed. (Provided you do not hit rock before that depth). If you hit water while digging the pit, you need to ask the workers to be careful while they continue digging. The diameter of the pit you choose depends on two things: space available and the quantity of water you will send in.  A 3 feet dia X 20 feet pit will ‘hold’ around 4000 litres (for recharging the ground). A 5 feet x 30 feet structure can hold 16000 litres.

    27. Question 27. What Are The Legal Guidelines And Their Implication For Recharge Pit Sizes?

      Answer :

      As per the law, you need to store or recharge 20 litres for for every sq.m of roof area and 10 litres for every sq.m of non-roof (ground surfaces such as parking, backyard) area. This is for plot sizes of 40x60 sq.m or more.  For e.g. if your home has about 100 sq.m of roof area, and about 50 sq.m of non-roof area, then you will need to create capacity for at least 2500 litres of  water. If you are using a 1000 litre tank to store rainwater for immediate use, you can connect the overflow to a 4000 litre (3 feet x 20 feet) recharge well.

    28. Question 28. How Much Do Recharge Pits Cost?

      Answer :

      The cost of digging a 3 feet diameter well, which is 20 feet deep, is approximately Rs 20,000.

    29. Question 29. What Are The Basic Steps To Begin The Process Of Rwh?

      Answer :

      3 steps to begin RWH:

      Step 1:  Ask yourself: Why Rainwater Harvesting

      In many cases RWH is implemented to achieve all three of these objectives. 

      • Is it a source of supplemental water (thus reducing demand from your existing sources)
      • Is it to recharge ground water sources as you are dependent on borewells/open wells
      • Is it also as a flood control measure

      Step 2: 

      • Understand the strategy for your layout.
      • Consider the land use pattern
      • Choose domestic RWH system with storage tank or use an existing sump as storage
      • Need for investing in recharge wells
      • Engagement with people, discussion with other residents as water managers
      • Step 3:  Talk to an expert 

    30. Question 30. What Are The Benefits Of Rwh ?

      Answer :

      Flood mitigation: Appropriately designed recharge structures in open public spaces, will help keep the roads from flooding. When water is not allowed to leave the premises, the chances of it choking up the roads are minimal.

      Increasing groundwater levels: Marked improvement of both the quantity as well as the quality of the groundwater in areas which have implemented rainwater harvesting

      Greater water availablity: Rainwater collected in storage tanks is available as and when needed

      Prevents soil erosion and flooding especially in urban areas

    31. Question 31. Is Rwh A New Trend?

      Answer :

      RWH can be traced back to thousands of years in India. Our ancestors traditionally harvested rainwater through tankas, johads, madakas and many such local innovative structures that can be seen even today, across the country. 

    32. Question 32. Which Of The States Have Taken Action To Promote Rainwater Harvesting ?

      Answer :

      In compliance to CGWA (Central Ground Water Authority) directions, steps have been taken by states/UTs to promote and to make rainwater harvesting mandatory. Andhra Pradesh, Gujarat, Haryana, Himachal Pradesh, Kerala, Madhya Pradesh, Maharashtra, Tamil Nadu, Ranchi Regional Development Authority, Bombay Municipal Corporation and Pimpri – Chinchwad Municipal Corporation, Municipal Corporation of Ludhiana, Improvement Trust, Jalandhar, Jaipur Municipal Corporation, Mussorie Dehradun Development Authority, and Union Territories of Delhi, Daman & Diu and Puducherry have made necessary provisions in their building bye-laws to make installation of rain water harvesting systems mandatory.

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