presentation on environmental impacts of water resource projects and transpiration

8/2/2019 Presentation on Environmental Impacts of Water Resource Projects and Transpiration

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Presentation on environmentalimpacts of water resource

projects and transpiration


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Introduction

76%of total water is used by agriculture, 6.2%by power generation, 5.7% by the industries.

Impacts of W.R.P. on the environment are quite

diverse. The diversity may be due to varieties of

resources and associated transformation ofthese resources.

These impacts may be political, social,economical and environmental.


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Environmental impacts

Impacts caused by dams and reservoirs.

Down stream effects caused by alternationin hydraulic regime.

Regional effects in terms of overallaspects including resources use and socio-economic impacts.


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Impacts by the dams

Effects on Floating debris, fish, boats

Effects on Sediment load

Effects on Sedimentation

Effects on Nutrient transport

Effects on Retention of water from smalland moderate floods

Effects on Tidal barriers and barrages

Effects on sea


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Effects on Floating debris fish, boats

A dam is obstacle to the passage of trees,ice, wildlife, fish and boats.

Overflow spillways also permit thepassage of debris.


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Effects on sediment load

A dam can completely blocks the passageof the sediments conveyed by river.

Blocked bed load may disturb the balanceof delta areas.

Due to reduction in suspended solid loadmay deprive arable sand of silt.


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Effects on sedimentation

The settled sediments reduce the storagecapacity of the reservoir.

When desedimented water released fromreservoir into river then it tends toreacquire its sediment load and erodesthe bank of the canal.

This erosion reduces the stability of thecanal


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Effects on nutrient transport

Decomposition of suspended nutrients inreservoir may have consequence foraquatic biota downstream.

It also responsible for smaller sardinecatches in delta


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Action on retention of water fromsmall and moderate floods

Small floods provides ready access tospawning and renew the water in them.

They prevent the river banks becomingovergrown with trees.

They brings nutrients into lake and ponds.


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Effects on tidal barriers andbarrages

These barriers and barrages are effectedof preventing some upstream tidal flow.

Coastal protection works need to be raisedagainst this effect.


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Effects on sea

Large number of dams affect the foodweb structure of sea.

Bio-geo-chemical cycling of materials ofcoastal seas are also affected.


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Effect of flooding on fauna

Many animals die due to new reservoir.

Some animals migrate to new areas.

A few animals accommodate to the newenvironment.

Birds such as water-fowl and waders move

into new water habitat.


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Effect on climate

Change in temperature

Formation of fog

Formation of a new microclimate Change in rainfall pattern


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Effects on reservoir water

Water temperature:-in deep reservoir, there isdifference occurs b/w the temperature of upper layerand inflow.

Dissolved gas content:-it depends upon fourfactors

1)the extent of thermal layering in the reservoir

2)the depth of the intake under the water surface.

3)the amount of organic material present.4)the amount of decomposition product in th reservoir


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Nitrogen and oxygen supersaturation:-it will decrease with thedepth of water.

Eutrophication:-taste and odourproblem can develop in drinking water.

* water treatment process itself can also

become more expensive.* large masses of dead algae can

accumulate on beach with negative

effects.* excessive algal densities can interfere

significantly with swimming.


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Dissolved solid content:-A complexeffect can be occur here by suchmechanism, as oxidation, reduction, andion exchange.

*Area can vulnerable to water loggingand salinization


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Effect on Health:-Main disease spread

that is malaria, bilharziasis caused byblood flukes.

Malaria is transmitted by the bite of a

small fly of the simuliidae family. Bilharziasis is caused by transmitted

trough a snail.


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Action on water other than in thereservoir

Drying up of water

Change in water table

Catchment management landside


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Induced earthquakes

Earthquakes are due to release of pre-existing stresses

These are shallow, generally less than10km deep

There is a possibility of load influenceseismicity can be reduced


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Transpiration

Transpiration is the loss of water from a plant byevaporation

Water can only evaporate from the plant if thewater potential is lower in theairsurrounding the plant

Most transpiration occurs via the leaves

Most of this transpiration is via the stomata.


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Importance

Transpiration is not simply a hazard ofplant life. It is the "engine" that pullswater up from the roots to:

supply photosynthesis (1%-2% of the total)

bring minerals from the roots for biosynthesiswithin the leaf

cool the leaf


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leaves

The exchange of oxygen and carbondioxide in the leaf (as well as the loss ofwater vapor in transpiration) occurs

through pores called stomata(singular = stoma).

Normally stomata open when the light

strikes the leaf in the morning and closeduring thenight.

H T i ti i


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How Transpiration isMeasured

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The rate of water lossfrom the shoot can bemeasured under different

environmental conditions

volume of water taken upin given timeLimitations

measures water uptake

cutting plant shoot may damage plant

plant has no roots so no resistance to water being pulled up

Water is pulled up

through the plant


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Rate of transpiration

Time Osmotic Pressure,lb/in2

7 A.M. 21211 A.M. 4565 P.M. 272

12 midnight 191

6 E i t l F t


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6 Environmental FactorsAffecting Transpiration

1. Relative humidity:- air inside leaf is saturated (RH=100%).The lower the relative humidity outside the leaf the faster therate of transpiration as the gradient is steeper

2. Air Movement:- increase air movement increases the rate oftranspiration as it moves the saturated air from around theleaf so the gradient is steeper.

3. Temperature:- increase in temperature increases the rate oftranspiration as higher temperature

Provides the latent heat of vaporisation

Increases the kinetic energy so faster diffusion

Warms the air so lowers the of the air, so gradient is steeper


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4.Atmospheric pressure:- decrease in atmosphericpressure increases the rate of transpiration.

5. Water supply:- transpiration rate is lower if there is littlewater available as transpiration depends on the mesophyllcell walls being wet (dry cell walls have a lower ).When cells are flaccid the stomata close.

6. Light intensity :- greater light intensity increases the rateof transpiration because it causes the stomata to open, soincreasing evaporation through the stomata.


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The Effect of Wind Speed on theRate of Transpiration

Stomata diameter/m

10 20

Stomataltranspiration rate

/ gcm-2s-1 In still air closing thestomata is less effective incontrolling thetranspiration rate

moving air

still air

Moving Air Removes the Boundary Layer of


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Moving Air Removes the Boundary Layer ofWater Vapour From the Leaf

Boundary layer

Saturated air accumulates around leaf

Still air Moving air

Lower

Water vapour is removed from theleaf surface

the gradient is increased,so faster rate of waterevaporation via the stomata

cross section through a leaf

Refrences


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Refrences

1. Gopal, B. and K.P. Sharma, 1981. Water-Hyacinth (Eichhornia crassipes)the most troublesome

weed of the world. Hindasia Publ., pp: 128.

2. Ludang, Y. and S. Mangkoedihardjo, 2009. Leaf Area Based TranspirationFactor for Phytopumping of High Organic Matter Concentration. Journal of Applied

Sciences Research, 5(10): 1416-1420. 3. Little, E.C.S., 1967. Progress report on transpiration of some tropical

water weeds. PANS., 13: 127-132. 4. Dunigan, E.P., Z.H. Shamsuddin and R.A. Phelan, 1975. Can water-

hyacinth eat pollution?. Compost Sci., 16(2): 11. 5. Mangkoedihardjo, S., 2007. Leaf Area for Phytopumping of Wastewater.

Applied Ecology and Environmental Research, 5(1): 37-42 7. Wooteh, T.W. and J.D. Dodd, 1976. Growth of water hyacinth in treated

sewage effluent. Econ.Bot., 30: 29-37.


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presentation on environmental impacts of water resource projects and transpiration

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