Naba Bhattacharjee Threats to Umiam - India Water Portal

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21 Φεβ 2014 (πριν από 3 χρόνια και 5 μήνες)

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UMIAM LAKE



FACING EXTINCTION!

Umiam Lake
-

Snippets


Reservoir

of

Umiam

Hydel

Project



Stage

I
.


Commissioned

in

1965



Ist

Hydel

Project

of

NE
.


Area


10
.
27

sq

km
;

Area

of

catchment


220

sq

km


Engineering

marvel

with

life

span

till

2115

faces

extinction

within

2040

if

present

ecological

impingement

continues

unabated
.


Immense

tourism

potential

besides

power

generation

remains

to

be

harnessed
.


FACTORS ENDANGERING LIFE OF
LAKE.


Colossal flow of the following from catchments:


Sediment & Silt.


Sewage.


Solid Waste.


Multiple pollutants.


Rise of lake bed level due to enormous deposit of above materials
reducing volume of water holding capacity.




What causes such inflow into the lake:


Topographical location


valley; surrounded by hilly catchments.


Extensive ecological degradation including loss of forest cover in
catchments made soil totally vulnerable to erosion & displacement.


Multiple network of streams originating & flowing through
catchments discharge into Wah Umkhrah or Umshyrpi which join
with Wah Roro & finally drain into the lake.



What reveals the grim scenario!


Hydrographic survey


Water quality analysis


Situation analysis & assessment study of lake
catchments.


Sediment flow rate data.

Factors responsible for denigration of
catchments:


Hilly

terrain

with

deep

gorges

&

ravines
.


Extensive

loss

of

forest

cover

rendering

vast

stretches

into

“open”

land

exposed

to

severe

erosion

leading

to

destabilization

of

soil

profile

&

structure
.


Population

growth

and

human

activities

like

deforestation
;

diverse

land

use

pattern
;

faulty

cultivation
;

lack

of

soil

&

water

conservation
;

random

mining

&

quarrying
;

unplanned

development

of

road,

buildings

et

al
.



Is the situation beyond salvage?

Grim! But not yet if we act now.



Implement

tangible

remedial

&

preventive

measures

simultaneously
.


Multi

pronged

approach

both

short

&

long

term
.


Administrative

measures

&

enactment

of

relevant

prohibitive

Acts

&

invoking

existing

ones

with

diligence
.


People’s

participation

through

mass

awareness

&

sensitization

campaign
.

Interventions ~



Holistic Action Plan for reclamation & rehabilitation of
catchments: Massive afforestation programme


all other
measures incidental & essential with depletion of this cover.


Extensive soil conservation measures with focus to check
run
-
off & haphazard movement of water to the lake.


Stream management strategy to check silting of such
seasonal / perennial drainage channels; reducing flooding &
maintaining optimal capacity to canalize storm water.


Essence of rehabilitation need to be based on National River
Conservation Plan & National Lake Conservation Plan.


Regulate inflow into Lake.































A viable cyclic technology for treatment of sewage, effluent &
other pollutants and regulating sediment, plastic, paper et al
in waste water including tertiary treatment before transfer is
allowed into the lake.


An alternative route for sewage transfer avoiding the lake.


Dredging & Excavation


most effective mechanism to
remove huge silt and other contaminant deposit.


Plug possible seepage points evident in reservoir revealed
from down stream discharge study.


Engineering structures as ancillary preventive measures.


Remedial measures primarily desiltation techniques like
flushing, density current venting, sluicing et al is imperative.


CYCLIC ACTIVATED SLUDGE TECHNOLOGY

RESERVOIRS



Meant for ~


FLOOD CONTROL


IRRIGATION


DRINKING WATER


HYDROPOWER


INDUSTRIAL


Endangered by
Sedimentation


RESERVOIR SEDIMENTATION
PROBLEM


STORAGE CAPACITY LOSS



DECREASE OF LIFE TIME


SEDIMENTATION FACTORS


RESERVOIR SHAPE


SEDIMENT CHARACTERISTICS


RESERVOIR OPERATION


SEDIMENT/ RESERVOIR VOLUME RATIO


INFLOW CAPACITY

RELATIONSHIP


DEPOSIT AREA















Back
Water
Area

Delta
formation
Area

Bottom
Deposit
Area

Reservoir
Level

DAM

Streambed

STAGE: II









Flood control space

Conservation Storage

Inactive Storage

Dead Storage

Outlet

STAGE: III











Flood control space

Conservation Storage

Inactive Storage

Dead Storage

Outlet

STAGE: IV













Flood control space

Conservation Storage

Inactive Storage

Dead Storage

Outlet












STAGE: V

Flood control space

Conservation Storage

Inactive Storage

Dead Storage

Outlet

BACKWATER DEPOSIT
CHARACTERISTICS


COARSE SAND & GRAVEL


UPSTREAM DEPOSIT ABOVE RESERVOIR
LEVEL


DEPOSIT GROWS UPSTREAM & RESERVOIR


POSSIBLE EROSION DURING HIGH POOL
WATER LEVEL

BOTTOM DEPOSIT
CHARACTERISTICS


SILT & CLAY


TRANSPORTED BEYOND DELTA


SEDIMENTATION CLOSE TO DAM


RESERVOIR TURBIDITY


FLUSHING















Flood control space

Conservation Storage

Inactive Storage

Dead Storage

Outlet

SLUICE OPEN


RAINY SEASON

WATER &
SEDIMENT

HYDROSUCTION BYPASSING















Outlet

SEDIMENT
DIVERSION

BYPASS
PIPELINE

SEGMENTATION & DRY
EXCAVATION

























AREA CLOSED BY DYKES &
DRIED FOR EXCAVATION

DYKE CUM
ROAD FOR
MACHINERY

DREDGING



Material


Process


Dredger types


Disposal













.













Thank You.