Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Flood Operations in Central NSW Australia

440 views

Published on

Flood Operational Procedures for training dam staff

Published in: Technology
  • Be the first to comment

  • Be the first to like this

Flood Operations in Central NSW Australia

  1. 1. Flood Operations in Central Area of NSW Dr Muhammad Junaid Siddiqi State Water corporation Dubbo, NSW, Australia
  2. 2. Dam Locations
  3. 3. Burrendong Dam Asset Type Major Gated Dam Customer Service Area Central Valley Macquarie Name of Waterway Macquarie River Nearest Town Wellington When Commissioned 1967 GPS Latitude 32.41.136 GPS Longitude 149.07.986 Description of Dam Rockfill with clay core Storage Capacity 1,188,000 ML Catchment 13,900 km 2 Outlet Capacity 8,200 ML/day Spillway Type Gated concrete chute Power Station 19 MW Crest Length 1,113 metres Dam Height 76 metres Current Usage Water Conservation Town Water Supply Stock and Domestic Irrigation Environmental Flow Hydro-Power
  4. 4. Windamere Dam Asset Type Minor Ungated Dam Customer Service Area Central Valley Macquarie Name of Waterway Cudgegong River Nearest Town Mudgee When Commissioned 1984 GPS Latitude 32.45.396 GPS Longitude 149.47.058 Description of Dam Rockfill with clay core Storage Capacity 368,120 ML Catchment 1,060 km 2 Outlet Capacity 2,333 ML/day Spillway Type Uncontrolled unlined rock cutting Power Station Potential [2 MW] Crest Length 825 metres Dam Height 67 metres Current Usage Water Conservation Town Water Supply Stock and Domestic Irrigation
  5. 5. Wyangla Dam Asset Type Major Gated Dam Customer Service Area Central Valley Lachlan Name of Waterway Lachlan River Nearest Town Cowra When Commissioned 1968 (gates 1971) GPS Latitude 33.56.160 GPS Longitude 149.00.492 Description of Dam Rockfill with clay core Storage Capacity 1,220,000 ML Catchment 8,300 km 2 Outlet Capacity 6,700 ML/Day Spillway Type Gated concrete chute Power Station 18 MW Crest Length 1,372 metres (1.5 km incl spillway) Dam Height 85 metres Current Usage Water Conservation Town Water Supply Stock and Domestic Irrigation Environmental Flow Hydro-Power
  6. 6. Carcoar Dam Asset Type Minor Ungated Dam Customer Service Area Central Valley Lachlan Name of Waterway Belubula River Nearest Town Carcoar When Commissioned 1970 GPS Latitude 33.36.414 GPS Longitude 149.11.802 Description of Dam Concrete Arch Storage Capacity 35,800 ML Catchment 230 km 2 Outlet Capacity 1,470 ML/day Spillway Type Free overflow Power Station No Crest Length 269 metres Dam Height 52 metres Current Usage Water Conservation Town Water Supply Stock and Domestic Irrigation
  7. 7. Flood Warnings  Bureau of Meteorology responsibility – They hold specific indemnity – SWC does NOT issue flood warnings – Should NOT estimate river heights under flood conditions – it is NOT our role – We work with the flood forecast group of BOM in NSW – Also maintains close cooperation with State Emergency services
  8. 8. SCADA-Supervisory Control and Data Acquisition
  9. 9. BURRENDONG DAM  7 Radial gates - 16.76 m x 6.10 m  Full supply level - 1,190.060 GL (344.733 m)  Flood level - 1,679.720 GL (350.829 m)  Top of gates - 1,706.890 GL ( 351.134 m)  Gates Withdrawn - 2,274.330 GL (356.925 m)
  10. 10. BURRENDONG DAM  Irrigation Outlets - 3 x 60” Hollow Jet Valves at full capacity 5,850 ML/d  1 x 30” By-pass Valve (335 ML/d)  1 Hydro (at full capacity 3,500 ML/d)  Optimum release at full capacity = 5,850+3,500+335 = 9,685 ML/d
  11. 11. General Information  During Floods low level valves may kept open partially in order to flush out mud and other debris  Graph A helps to determine amount to be released  Graph B will tell you PI setting required to release previously determined amount
  12. 12. GATE OPERATION  Unlike Sector Gates which are lowered, Radial Gates are raised to release water  All 7 Radial gates are raised in unison  When operating, storage releases and gate openings are determined by using Nomographs found in the Flood Ops Manual
  13. 13.  To maintain the safety of the Dam at all times  Minimise the effect of the flood peak downstream of the Dam. This can be by either minimising the peak outflow or delaying releases to allow for D/S tributaries to subside (This may need to be reassessed in the future) DAMOPERATING PROCEDURE
  14. 14. Procedural Rules  Always maintain 0.3 mitres of freeboard  Never allow the storage level to exceed maximum permissible water level while gates are still raised  Rate of outflow never to exceed the rate of inflow until the flood has peaked
  15. 15. HOW PROCEDURES WORKS  It assumes inflow is at its peak at the time of reading.  Adds on an average recession derived from past floods  Works out how much Volume is in the recession  Works out the gate opening needed so that the expected future inflow can be stored exactly in the airspace(pondage) created by the raising of the gates  In these calculations it is assumed that the storage will reach the maximum permissible storage level at the time that ‘Inflow = Outflow’
  16. 16. CALCULATION OF INFLOWS  Estimated by calculating the apparent inflow at the dam wall.  This is done by calculating the volume of water that flowed into the dam in the last time period (say 1 hour).  Total Inflow = rVolume + Outflow
  17. 17. TYPES OF PROCEDURE Three Types of Procedures Forecast Procedure Aimed at achieving the maximum d/s mitigation while still ensuring the safety of the dam. Use forecast flows both u/s and d/s, rainfall information, info from a number of other sources. Emergency Procedure Primary aim is to ensure the safety of the dam. Provide some d/s mitigation. Crisis Procedure Only aim is to ensure the safety of the dam.
  18. 18. Airspace Operation Rules (d) each bay shall have different maximum rates of releases, and these releases which are above water orders, shall be equal to the inflow up to the maximum combined release, plus downstream tributary flow, and these releases shall be in accordance with the following: (i) bay 1—Burrendong Dam water storage between 100% and 120%, and releases to a maximum of 5,000 ML/day at Warren, which equates to approximately 5.5 metres at Warren town, Orders + 700 to 1 400 ML/d (ii) bay 2—Burrendong Dam water storage between 120% and 130%, and releases to a maximum of 12,000 ML/day at Gin Gin, which equates to approximately 6.5 metres at Warren town, and Orders + 1 400 ML/d Orders + 5 000 ML/d (if peak >131 %) (iii) bay 3—Burrendong Dam water storage between 130% and 142%, and releases to a maximum of 18,000 ML/day at Gin Gin, which equates to the minor flood level of 7.5 metres at Warren town, Orders + 5 000 ML/d 12 000 ML/d (if peak < 142 % & no flow @ Reddenville) 25 000 ML/d or D/S peak (if peak >142 % or flow @ Reddenville)
  19. 19. Airspace Operation Rules release rates lower or higher than those indicated in subclause (1) (d) for each FMZ bay may be made if: (i) the release rate specified in subclause (1) (d) will cause prolonged inundation of the floodplain and result in economic losses to agriculture, (ii) the release rates specified in subclause (1) (d) will restrict landholder access to their properties for extended periods, or (iii) the environment and community would benefit from lower or higher rates of release, and
  20. 20. Burrendong Nov 2000 0 50 000 100 000 150 000 200 000 250 000 16-Nov-00 17-Nov-00 18-Nov-00 19-Nov-00 20-Nov-00 21-Nov-00 22-Nov-00 23-Nov-00 24-Nov-00 25-Nov-00 26-Nov-00 27-Nov-00 28-Nov-00 29-Nov-00 30-Nov-00 01-Dec-00 02-Dec-00 03-Dec-00 04-Dec-00 05-Dec-00 06-Dec-00 ML/d 50% 60% 70% 80% 90% 100% 110% 120% 130% 140% 150% Inflow Release Storage
  21. 21. Macquarie River Nov 2000 0 20 000 40 000 60 000 80 000 100 000 120 000 16/11/000:00 17/11/000:00 18/11/000:00 19/11/000:00 20/11/000:00 21/11/000:00 22/11/000:00 23/11/000:00 24/11/000:00 25/11/000:00 26/11/000:00 27/11/000:00 28/11/000:00 29/11/000:00 30/11/000:00 1/12/000:00 2/12/000:00 3/12/000:00 4/12/000:00 5/12/000:00 6/12/000:00 7/12/000:00 Time at Burrendong (others lagged for travel time) ML/d Release Elong Elong Baroona
  22. 22. Burrendong Dam Capacity (%) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 110% 120% 130% 140% 150% Jul/95N ov/95M ar/96Jul/96N ov/96M ar/97Jul/97N ov/97M ar/98Jul/98N ov/98M ar/99Jul/99N ov/99M ar/00Jul/00N ov/00M ar/01Jul/01N ov/01M ar/02Jul/02N ov/02M ar/03Jul/03N ov/03M ar/04Jul/04N ov/04M ar/05Jul/05N ov/05M ar/06Jul/06N ov/06M ar/07Jul/07N ov/07M ar/08Jul/08N ov/08M ar/09Jul/09N ov/09M ar/10Jul/10 BurrendongStorage(%)
  23. 23. Flood Levels at Dubbo  Minor - 5.5 m = 57,000 ML/d  if conditions permit, try to maintain 57,000 ML/d or lower at Dubbo  Moderate - 7.9 m = 94,500 ML/d  Major - 11.0 m = 237,000 ML/d
  24. 24. Gate Operation  Graph A helps to determine amount to be released  Graph B will tell you PI setting required to release previously determined amount  During Floods only low level valves are kept partially open in order to flush out mud and other debris
  25. 25. WYANGALA DAM STRUCTURE  8 Radial gates - 14.63 m x 12.91 m  Full supply level - 1,217.670 GL (378.854 m)  Top of gates - 1028.35 GL ( 379.158 m)  Gates withdrawn - 1284.07 GL ( 380.073 m)
  26. 26. WYANGALA DAM  Irrigation Outlets - 2 Hollow Jet Valves & 1 FDC Valve – 1 x 30” Valve (640 ML/d) – 1 x 60” Valve (3,400 ML/d) – 1 x FDC Valve (3,100 ML/d)  Hydro A (at full capacity 2,600 ML/d)  Optimum release at full capacity = about 7,000 ML/d
  27. 27. GATE OPERATION  Unlike Sector Gates which are lowered, Radial Gates are raised to release water  All 8 Radial gates are raised in unison  When operating, storage releases and gate openings are determined by using Nomographs found in the Flood Ops Manual
  28. 28. Nomograph for Wyangala Radial Gates
  29. 29. Wyangla Dam Capacity (%) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Jun/01 O ct/01 Feb/02 Jun/02 O ct/02 Feb/03 Jun/03O ct/03 Feb/04 Jun/04 O ct/04 Feb/05 Jun/05O ct/05 Feb/06 Jun/06 O ct/06 Feb/07 Jun/07 O ct/07 Feb/08 Jun/08O ct/08 Feb/09 Jun/09 O ct/09 Feb/10 Jun/10O ct/10 Date WyanagalaStorage(%)
  30. 30. Flood Levels at Cowra  Minor - 8.5 m = 47,800 ML/d  if conditions permit, try to maintain 47,800 ML/d or lower at Cowra  Moderate - 10.7 m = 85,300 ML/d  Major - 13.4 m = 239,000 ML/d
  31. 31. EFFECTS OF SECTOR GATES •Unlike Radial Gates, Sector gates are lowered to release water
  32. 32. Inflow 40 GL/day Outflow 17 GL/day PI of 367 mm

×