conserving water mountain forests hold the key for saarc ...ku.edu.np/env/mrmce-2012/conserving...

Conserving Water: Mountain Forests ghold the Key for SAARC Region

Ajay Kumar Lalj y

30.05.2012aklal87@gmail comaklal87@gmail.com

WaterWater

Precious  and  vital  National  AssetPrime Natural ResourceEssential for existence of all Lives

Ch llChallenges

A il bilit    t S itAvailability  yet ScarcityRecharging yet  DepletionHuge  Investments  yet Diminishing  ResultsHuge  Investments  yet Diminishing  Results

SAARC REGION WATER AVAILABILITY

Country Renewable water 

Per Capita Agriculture Inputs water

Remarks

resourcesp

Km3 M3 M3/ha

Afghanistan NA NA NAg a staBangladeshBhutanIndia

1211951897

8232420351670

899925003289

MaldivesNepalPakistan

NA210223

NA74471353

NA40437407

Sri Lanka 50 2372 6283

World Average 8210 m3 per capitaWorld total Renewable Sources 54228 km3

Where  lies the  key ???

Not  in  dams/surface storages

but 

in  plantsin  plants

Hydrological Services by PlantsSurface Run Off Reduction

Water Table Change

Mitigating Floodsg g

Maintaining Rainfall Patterns

Reducing soil erosion

Scientifically established Facts through Research

Plantations/forests reduce run off by 28 to 30%.

Plantations / forests reduce peak discharge by as high as 72%.

Plantations / forests increase infiltration by almost 3 times.3

(FRI, India, Forest Influences Publication Series)

Rational Equation

Q=CIA/360

Infiltration:

Open 1.40 cm per hour - Cultivated land

5 30 h i d l t ti5.30 cm per hour - mixed plantation

3 0 cm per hour - grass land3.0 cm per hour grass land

Interception by plantations

(Stemflow) (throughfall) (interception)

P roxburgii 3 6% 74 3% 22 1%P. roxburgii 3.6% 74.3% 22.1%

T.grandis 6.0 % 73.2 % 20.8 %

S. robusta 7.2 % 54.6 % 38.2 %

A. Catechu 4.2 % 67.3 % 28.5 %

SAARC  REGION  AND  FORESTS      

Country Area (000sq 

Population ( million)

Forest Area(million ha)

% Forest Area

Remarks

km)

AfghanistanBangladesh

652.2147.6

26152

N A2.58

NA17.49g

BhutanIndiaMaldives

38.43287.20 298

0.6712150 29

17.59  69.09  0 001

72.521.13Maldives

NepalPakistanS i L k

0.298147.179665 6

0.2923.115319 4

0.0015.5 3.9 1 94

3375.128 2Sri Lanka 65.6 19.4 1.94 28.2

Water Table

Discharge reduction average 30%water saved = 120 x 0 55 x 0 3water saved = 120 x 0.55 x 0.3

= 19.75 cmF f 100 h 197500 3For an area of 100 ha = 197500 m3

If 20% is recharging the aquifer to be reusedDrinking water requirement fulfilled

= 0.2 X197500 / (0.05 x 365)= 2164 persons.

Small watershed afforestation reduces run off by 28% and peak by y p y73 %

( Study by Dr. H N Mathur CSWRI 1978)

GW Recharge ( An Illustration)

Indian Haryana state GW level depletion0.20 to 0.3 m per year

Plantations save 28% run off (average)

GW Recharge = 1.30 X 0.5 X 0.28 = 0.18 m every year

Automatic natural recharge

Irrigation Scenario (Indian Context)g ( )Irrigation potential addition

Average Cost of providing water to one ha of land during 7thAverage Cost of providing water to one ha of land during 7Plan = 4.24 lakh Rs.

(BB Bohra Irrigation of Nation Report Aug. 96)

Afforestation by same expenditure = 20 haVolume of water saved = 197500 x 20/100 = 39500 cu mVolume of water saved 197500 x 20/100 39500 cu m

If half can be reused for irrigationWater requirement of wheat = 0.4 x 100 x 100

= 4000 m3/haPaddy = 1.2 x 100 x 100

= 12000 m3/ha= 12000 m3/haSo, 1 ha, 2 crops potential created by spending 4.27 lakh Rs.

Reducing Soil Erosiong

Reduced by 38 5% (TERI G I di 2047)Reduced by 38.5% (TERI Green India 2047)

In Moderately eroded area ( erosion 7 t/ha/yr)In Moderately eroded area ( erosion 7 t/ha/yr)Erosion reduction = 0.38 x 7 = 2.6 t/ha/yrT t l t il d f 100 h 260 t /Total top soil saved for 100 ha =260 t / yearPrice = 57 000 Rs.

SedimentationSedimentation

A Case in PointA Case in PointBhakra Nangal

Catchments 56876 sq. kmq

Annual Rate of Siltation

Assumed 6 43 t/haAssumed 6.43 t/ha

Observed 9.21 t/ha

D i Lif d d f 99 t 61Design Life reduced from 99 years to 61 years

Th k YThank You