umiam lake facing extinction!
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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
DAMStreambed
STAGE: II
Flood control space
Conservation Storage
Inactive Storage
Dead StorageOutlet
STAGE: III
Flood control space
Conservation Storage
Inactive Storage
Dead StorageOutlet
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 StorageDead 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.