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UMIAM LAKE FACING EXTINCTION!

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

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UMIAM LAKE FACING EXTINCTION!

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  1. UMIAM LAKEFACING EXTINCTION!

  2. 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.

  3. 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.

  4. What reveals the grim scenario! • Hydrographic survey • Water quality analysis • Situation analysis & assessment study of lake catchments. • Sediment flow rate data.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. CYCLIC ACTIVATED SLUDGE TECHNOLOGY

  10. RESERVOIRS – Meant for ~ • FLOOD CONTROL • IRRIGATION • DRINKING WATER • HYDROPOWER • INDUSTRIAL Endangered by Sedimentation

  11. RESERVOIR SEDIMENTATION PROBLEM • STORAGE CAPACITY LOSS • DECREASE OF LIFE TIME

  12. SEDIMENTATION FACTORS • RESERVOIR SHAPE • SEDIMENT CHARACTERISTICS • RESERVOIR OPERATION • SEDIMENT/ RESERVOIR VOLUME RATIO • INFLOW CAPACITYRELATIONSHIP

  13. Reservoir Level DAM Streambed Delta formation Area Bottom Deposit Area Back Water Area DEPOSIT AREA

  14. Flood control space Conservation Storage Inactive Storage Dead Storage Outlet STAGE: II

  15. Flood control space Conservation Storage Inactive Storage Dead Storage Outlet STAGE: III

  16. Flood control space Conservation Storage Inactive Storage Dead Storage Outlet STAGE: IV

  17. STAGE: V Flood control space Conservation Storage Inactive Storage Dead Storage Outlet

  18. BACKWATER DEPOSIT CHARACTERISTICS • COARSE SAND & GRAVEL • UPSTREAM DEPOSIT ABOVE RESERVOIR LEVEL • DEPOSIT GROWS UPSTREAM & RESERVOIR • POSSIBLE EROSION DURING HIGH POOL WATER LEVEL

  19. BOTTOM DEPOSIT CHARACTERISTICS • SILT & CLAY • TRANSPORTED BEYOND DELTA • SEDIMENTATION CLOSE TO DAM • RESERVOIR TURBIDITY

  20. Flood control space Conservation Storage WATER & SEDIMENT Inactive Storage Dead Storage Outlet SLUICE OPEN – RAINY SEASON FLUSHING

  21. SEDIMENT DIVERSION BYPASS PIPELINE Outlet HYDROSUCTION BYPASSING

  22. DYKE CUM ROAD FOR MACHINERY AREA CLOSED BY DYKES & DRIED FOR EXCAVATION SEGMENTATION & DRY EXCAVATION

  23. DREDGING • Material • Process • Dredger types • Disposal

  24. . Thank You.

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