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Droughts in Ohio: Shall We be Worried?

Droughts in Ohio: Shall We be Worried? . Tiao J. Chang Department of Civil Engineering Russ College of Engineering, Ohio University Athens, Ohio 45701 Prepared for the WMAO 2009 Fall Conference November 5, 2009. Precipitations in Ohio Geographic Distribution (World Book).

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Droughts in Ohio: Shall We be Worried?

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  1. Droughts in Ohio: Shall We be Worried? Tiao J. Chang Department of Civil Engineering Russ College of Engineering, Ohio University Athens, Ohio 45701 Prepared for the WMAO 2009 Fall Conference November 5, 2009

  2. Precipitations in OhioGeographic Distribution (World Book)

  3. Precipitations in OhioTemporal Distribution (ODNR)

  4. Streamflows in Ohio:Athens Gauging Station(USGS)

  5. Streamflows in Ohio:Delaware Gauging Station(USGS)

  6. Ohio - Blessed Land As far as water is concerned, it is promised.

  7. Streamflows in Ohio:Athens Gauging Station(USGS)

  8. 1988 Drought in the Midwest

  9. 1988 Drought in the Midwest (Athens Messenger, 6-10-1988)

  10. 1988 Drought in the Midwest (Athens Messenger, 6-9-1988)

  11. 1988 Drought in the Midwest (Athens Messenger, 6-20-1988)

  12. 1988 Drought in the Midwest (Athens Messenger, June 1988)

  13. How to Define Droughts(AWRA Journal, October 1990)

  14. A 100-year Drought?(AWRA Journal, October 1990)

  15. Truncation Level of Drought IndicatorsStreamflow, Precipitation, Reservoir Level

  16. Drought DefinitionTemperature and Groundwater Drawdown

  17. Levels of Drought Severity 70% Drought Severity 80% Drought Severity 90% Drought Severity 95% Drought Severity

  18. A Drought Monitoring Method Operable under existing conditions Palmer Drought Severity Index (Palmer, 1965) Technically effective Acceptable by all parties

  19. Drought Indicators Streamflow Precipitation Groundwater Level - drawdown Temperature - Reservoir Level -

  20. Scioto River Basin

  21. Streamflow Gauging Stations (18)

  22. Example of Truncation Levels: Daily Streamflow Olentangy River at Delaware Mean daily flow: 10.00 cms 70% Truncation Level: 0.911 cms 80% Truncation Level: 0.651 cms 90% Truncation Level: 0.453 cms 95% Truncation Level: 0.312 cms

  23. Precipitation Gauging Stations (21)

  24. Temperature Gauging Stations (13)

  25. Groundwater Wells (14) & Reservoirs (4)

  26. Precipitation Gauging Stations (21)

  27. Mean Drought Durations

  28. Conditional Probabilityfrom 70% to 80%

  29. Severity Levels of Streamflow Drought Based on daily flow monitoring, a drought event is between two levels of severity Duration of current event ≥ Mean drought duration Conditional probability ≥ 0.50 Levels of Severity Selection Gauging Stations Indicator: majority of gauging stations

  30. Gauging Stations in the Basin

  31. Basinwide Drought Severity Levels Streamflow drought plus at least one other indicator exceeding the severity level of streamflow drought - Level of streamflow drought is selected. Streamflow drought plus at least one other indicator reaching 70% but not exceeding that of streamflow drought – 70% is selected Streamflow not reaching 70% but at least two other indicators are – 70% is selected

  32. Test for April 1988

  33. Test for May 1988

  34. Test for June 1988

  35. Summary: The monitoring method Groundwater drawdown indicated the drought event at the earliest stage. Precipitation is the most sensitive drought indicator. Based on the definition as stated, streamflow becomes the most critical basinwide drought indicator?

  36. Flood vs. Drought Reservoirs operated for flood control only Can that be for drought management?

  37. Four Reservoirs in the Basin

  38. Requirements for the Optimization Model Minimum release is required for each reservoir. Minimum streamflow at control stations according to demands at a given drought severity level. Mass conservation of a reservoir. Minimum reservoir elevation for a reservoir.

  39. Assumptions for the Optimization Model Maximum Release - the amount enclosed between the specified reservoir elevation and the 70% truncation level of the reservoir. Area Factor- contribution of a reservoir to a downstream control station is proportional to the drainage area of a reservoir. Distance Factor - contribution of a reservoir to a downstream control station is inversely proportional to the distance of the reservoir from the control station.

  40. Expression of Area Factor

  41. Expression of Distance Factor

  42. Objective Function of the Optimization Model

  43. Constraints for Minimum Flows at Control Stations

  44. Constraints for Mass Conservation of Involved Reservoirs

  45. Constraints for Minimum Releases from Involved Reservoirs

  46. Example of Constraints for 70% Drought Severity

  47. Example for Deer Creek- April 1988

  48. Example for Deer Creek-May 1988

  49. Example for Deer Creek-June 1988

  50. Example for Paint Creek-May 1988

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