BRANCH :civil-2

TOPIC :WATER RESOURCE ENGINEERING

Rajesh Goswami

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waterResources engineering

•Contents•Introduction•Hydrology•Water cycle• Watershed Development• Integrated Watershed Management• Water Conservation & Harvesting•Basic introduction of hydraulic structures.• conclusion•references

What is Water Resources Engr./Manag.?

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What is Hydrology?Hydrology is the study of the movement, distribution, and quality of water throughout the Earth, including the hydrologic cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of either earth or environmental science, physical geography, geology or civil and environmental engineering.

Water covers 70% of the Earth's surface

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Ancient Hydrologic History

WATERSECURITYAbundance

Security

Happiness

Suffering

Hunger

Disaster

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But hydrology is a young science….

Major Reservoirs of Water

Water Cycle

Floods are the first cause of fatalities and economic losses among natural disasters worldwide

Temporal evolution of natural catastrophes from 1980 to 2012

Source: MunichRE, NatCatSERVICE

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Floods

Floods cause extensive damage: “during 1991-1995, flood related damage totaled more than US$200 billion globally, representing close to 40% of all economic damage attributed to natural disasters in the period -- (Pielke Jr. and Downton, 2000, citing IFRCRCS, 1997). In the United States, annual flood damage runs in the billions of dollars (Pielke Jr. and Downton, 2000). Improved prediction of floods could reduce these costs substantially, in addition to reducing flood-induced loss of life.

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Droughts

Water Availability is Decreasing

The Future?By the year 2025 nearly 2 billion people will live in regions or countries with absolute water scarcity, even allowing for high levels of irrigation efficiency.

YearWorld

Population (billions)

2010 6.8

2020 7.6

2030 8.2

2040 8.7

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Water Scarcity Index Rws

Rws

Total Water Withdrawal – Desalinated Water

Renewable Freshwater ResourcesRws =

Typical Domestic Water Use

• 100-600L/person/day (high-income countries)• 50-100L/person/day (low-income)• 10-40L/person/day (water scarce)

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Human Usage

Water Stress• Based on human consumption and linked to

population growth• Domestic requirement:

– 100L/person/day = 40m3/person/year– 600L/person/day = 240m3/person/year

• Associated agricultural, industrial & energy need:– 20 x 40m3/person/year = 800m3/person/year

• Total need:– 840m3/person/year– 1040m3/person/year

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Water Stress [m3/person/year]

• Water scarcity: <1000 m3 /person/year– chronic and widespread freshwater problems

• Water stress: <1700 m3 /person/year– intermittent, localised shortages of freshwater

• Relative sufficiency: >1700 m3 /person/year

The Lake Aral disaster

Integrated Water Resources

Integration of -

- River basin resources- surface and ground.

- Demands - consumptive and non-consumptive, and supplies.

- Facilities - mega to micro.

- Human and eco-systems.

- engineering with social, economic, synergic needs.

INDIA’S LAND RESOURCE, IRRIGATION AND FOOD PRODUCTION• India has 2% of world’s land, 4% of freshwater, 16% of population, and 10% of its cattle.• Geographical area = 329 Mha of which 47% (142 Mha) is cultivated, 23% forested, 7% under non-agri use, 23% waste. • Per capita availability of land 50 years ago was 0.9 ha, could be only 0. 14 ha in 2050.• Out of cultivated area, 37% is irrigated which produces 55% food; 63% is rain-fed producing 45% of 200 M t of food. • In 50 years (ultimate), proportion could be 50:50 producing 75:25 of 500 M t of required food.

WITHDRAWAL OF WATER- 2050, AVAILABILITY

India’s Yearly Requirement in 2050 (Km3 = Billon cubic meter)• For growing food and feed at 420 to 500 million tonnes = 628 to 807 BCM• Drinking water plus domestic and municipal use for rural population at 150 lpcd and for urban population at 220 lpcd = 90 to 110 BCM•Hydropower and other energy generation = 63 to 70 BCM•Industrial use = 81 to 103 BCM•Navigational use = 15 BCM•Loss of water by evaporation from reservoirs = 76 BCM•Environment and ecology = 20 BCMTotal 970 to 1200 BCMAvailability 1100 to 1400 BCM

Where does the water come from? •New dams - •Groundwater - underdeveloped•Demand Management•Water savings - increase in efficiency, reduce evaporation.•Water productivity - increases in crop per drop•Trade (virtual water), import food.

Water Conservation & Harvesting

Total water management for

sustainable development?.

Water Conservation• Important step for solutions to issues of water and

environmental conservation is to change people's attitudes and habits .

• Conserve water because it is right thing to do!.• What you can do to conserve water?• Use only as much water as you require. Close the taps well

after use. While brushing or other use, do not leave the tap running, open it only when you require it. See that there are no leaking taps.

• Use a washing machine that does not consume too much water. Do not leave the taps running while washing dishes and clothes.

Water Conservation…• Install small shower heads to reduce the flow of

the water. Water in which the vegetables & fruits have been washed - use to water the flowers & plants.

• At the end of the day if you have water left in your water bottle do not throw it away, pour it over some plants.

• Re-use water as much as possible• Change in attitude & habits for water

conservation• Every drop counts!!!

Rain Water Harvesting?. • Rain Water Harvesting RWH- process of collecting, conveying & storing water from rainfall in an area – for beneficial use. • Storage – in tanks, reservoirs, underground storage- groundwater• Hydrological Cycle

Rain Water Harvesting?. • RWH - yield copious amounts of water. For an average rainfall of 1,000mm, approximately four million litre of rainwater can be collected in a year in an acre of land (4,047 m2), post-evaporation. •As RWH - neither energy-intensive nor labour-intensive.•It can be a cost-effective alternative to other water-accruing methods. • With the water table falling rapidly, & concrete surfaces and landfill dumps taking the place of water bodies, RWH is the most reliable solution for augmenting groundwater level to attain self-sufficiency.

• Roof Rain Water Harvesting• Land based Rain Water Harvesting• Watershed based Rain Water harvesting• For Urban & Industrial Environment –

• Roof & Land based RWH • Public, Private, Office & Industrial buildings• Pavements, Lawns, Gardens & other open

spaces

RWH – Methodologies

Rain Water Harvesting– Advantages 1.Provides self-sufficiency to water supply 2.Reduces the cost for pumping of ground water 3.Provides high quality water, soft and low in minerals4.Improves the quality of ground water through dilution when recharged5.Reduces soil erosion & flooding in urban areas6.The rooftop rain water harvesting is less expensive & easy to construct, operate and maintain

7. In desert, RWH only relief 8. In saline or coastal areas & Islands, rain water provides good quality water

Yearly rainfall departure from the mean for rainfall station guina

Seasonal rainfall departure are extremely variable.

Resources mapping: Surface water storageRe

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Total number of reservoirs = 144

Storage capacity = 81.3 x 106 m3

Appropriate Technology

Water conservation and groundwater recharge techniques

Water harvesting cum supplementary irrigation

Water ConservationWater conservation interventions includes contour trenches, gully plugging, vegetative and field bunding, percolation tanks. Overall land treatment against potential area is varying between 40-60%.

45%

30%

25%

Private land Fallow land Forest land

Type of land ownership for soil and water conservation measures

A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by utilizing the weight of the material alone to resist the horizontal pressure of water pushing against it. Gravity dams are designed so that each section of the dam is stable, independent of any other dam section.

DAMSGravity dam

What is earthen dam?

• Earth fill dam, also called Earth Dam, or Embankment Dam.

• Dam built up by compacting successive layers of earth, using the most impervious materials to form a core and placing more permeable substances on the upstream and downstream sides.

• A dam built of soil materials (sand, loam, clay, and so on), with a trapezoidal or nearly trapezoidal cross section.

Rock fill damRock-fill dams are embankments of compacted free-draining granular earth with an impervious zone.

The earth utilized often contains a high percentage of large particles hence the term rock-fill.

A concrete-face rock-fill dam (CFRD) is a rock-fill dam with concrete slabs on its upstream face.

Rock fill dam

Concluding RemarksThe integrated watershed management approach have the following major components:

• Promote sustainable economic development through optimum utilisation of natural resources and local capacity building. • Restore ecological balance through community participation and cost affordable technologies for easy acceptance.

• Improving living conditions of the poorer through more equitable resources distribution and greater access to income generating activities.

Concluding Remarks

•Efficient utilisation of funds as only 10-15% of the total budget spent on non-project costs.

• The benefits of water harvesting and water conservation not only for drinking water security but also for agriculture definitely reached.

• About 2-4 meter water level increase is observed in selected wells.

• Watershed management can easily cope with climate change impacts.

ReferencesGoogle.comWikipedia.orgwww.eoearth.org/wiki/Water_resourcesiwrs.org.in/iwr.htmwww.greenfacts.org/en/water-resourceshttps://www.youtube.com/?gl=IN