SlideServe
Télécharger Obtenir Pro
Menu
Accueil Pro
Préférences
ApparenceLight Aide et commentaires
© SlideServe · v2026

Analysis of Raleigh's Drought Triggers and Response Plan

jeroen avatar
jeroen
30 diapositives · 402 Views · Aug 20, 2014

Evaluate frequency and effectiveness of Raleigh's current drought plan, proposing revisions based on historical data and modeling parameters. Consider climate change impact and drawdown-refill cycles in water supply management.

#analysis of raleigh's drought triggers and response plan #analysis of raleigh's drought triggers and response plan ppt #powerpoint #presentation
Analysis of Raleigh's Drought Triggers and Response Plan - slide 1
01 / 30Analysis of Raleigh's Drought Triggers and Response Plan
1 / 17

Télécharger la présentation

Analysis of Raleigh's Drought Triggers and Response Plan
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation

Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement. Téléchargez la présentation en cliquant sur ce lien. Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.

F I N

Plus de contenu associé

Transcription de la présentation

  1. Analysis of Raleigh’s Drought Triggers May 8, 2013 and

  2. Background • Previous assessments of current drought plan showed high frequency (as much as 1 out of every 3 years) of plan activation at current demands. Drought plan often triggered at times when it’s implementation is unnecessary and ineffective. • Modeling parameters of previous assessments were more conservative; lower Swift WD, steeper demand pattern, higher triggers

  3. Previous Drought Plan • Stage 1 • Activation : Falls Water Supply Storage Account <= 50% • Lift restrictions at 90% WS Storage • Primary restriction is limiting spray irrigation to 1 day/week • Stage 2 • Activation : Falls Water Supply Storage Account <= 30% • Lift restrictions at 70% WS Storage • Residential spray irrigation prohibited. Golf course 50% reduction, carwashes only on weekends, some indoor reduction expected. • Stage 3 • Activation : Falls Water Supply Storage Account <= 10% • Lift restrictions at 50% WS Storage • Many non-essential uses banned and almost all outdoor use is banned. Numerous indoor/commercial reductions mandated.

  4. Frequency of Trigger Activation with Current Drought Plan, Last 30 Years of Record 1 in 3 yrs 1 in 4 yrs 1 in 8 yrs

  5. Questions to Consider • Are you comfortable with the frequency of drought plan activation? • What is the appropriate waiting period between stages? • Is a more rigorous climate change analysis warranted?

  6. Drawdown-Refill Cycles • Falls Lake Water Supply has regular refill / drawdown cycle Drawdown Phase Refill Phase

  7. Water Shortage Response Plan Response by Stage Estimate contained in WSRP is a flat reduction, but in reality reductions will be greater during the irrigation season and lesser during winter months. 7

  8. Seasonal Reductions in Drought Stages • Based on Hazen & Sawyer’s analysis of 2010 demand trends (indoor, outdoor, etc.)

  9. Water Shortage Response Plan Annual Average Response by Stage Draft * - Response dependent on season. Estimate presented here is simply an average of the estimates made for each of the 12 months. 9

  10. Modeling Assumptions – All Scenarios • Use 2010 monthly demand pattern • Total Average Annual Daily Demand = 60 mgd • Benton plant operations • 8 mgd constant withdrawal • Increase to 9.5 mgd when entering Stage 1 of drought plan • Never drop EMJ/Falls WD below 36 mgd • Assume 30 day waiting period between triggers

  11. Seasonal Drought Plan • Each stage’s storage trigger varies by month • Rescission triggers at same levels as current drought plan • Assume same demand reductions as current drought plan

  12. Seasonal Drought Plan, Option 2 • Higher Stage 1 & 2 spring triggers • Rescission triggers at same levels as current drought plan • Assume same demand reductions as current drought plan

  13. Frequency of Alert Trigger Activation, Last 30 Years of Record 1 in 3 yrs 1 in 5 yrs 1 in 6 yrs

  14. Effect of Maximizing Swift Creek Withdrawals • Maximum Swift withdrawal • 14 mgd when Benson/Wheeler storage >= 60% • 12.6 mgd when Benson/Wheeler storage >= 30% • 11.2 mgd when Benson/Wheeler storage < 30% • Never drop EMJ/Falls WD below 36 mgd

  15. Max Swift Creek Scenarios, Last 30 Years of Record 1 in 4 yrs 1 in 8 yrs 1 in 10 yrs

  16. Max vs. 8 mgd Swift Creek Scenarios, Last 30 Years of Record 1 in 3 yrs 1 in 4 yrs 1 in 5 yrs 1 in 6 yrs 1 in 8 yrs 1 in 10 yrs

  17. Days in Drought Restrictions, Current Plan,60 mgd total demand, 8 mgd Swift WD Statistics for last 30 years Median Start Date = Oct. 2 Median End Date = Feb. 10 Median Duration = 130 days Max Duration = 210 days

  18. Days in Drought Restrictions, Seasonal Plan,60 mgd total demand, 8 mgd Swift WD Statistics for last 30 years Median Start Date = Oct. 10 Median End Date = Feb. 25 Median Duration = 119 days Max Duration = 196 days

  19. Days in Drought Restrictions, Seasonal Plan 2,60 mgd total demand, 8 mgd Swift WD Statistics for last 30 years Median Start Date = Oct. 20 Median End Date = Mar. 17 Median Duration = 122 days Max Duration = 196 days

  20. Days in Drought Restrictions, Current Plan,60 mgd total demand, Max Swift WD Statistics for last 30 years Median Start Date = Oct. 23 Median End Date = Jan. 30 Median Duration = 82 days Max Duration = 195 days

  21. Days in Drought Restrictions, Seasonal Plan,60 mgd total demand, Max Swift WD Statistics for last 30 years Median Start Date = Oct. 14 Median End Date = Feb. 1 Median Duration = 101 days Max Duration = 175 days

  22. Days in Drought Restrictions, Seasonal Plan 2,60 mgd total demand, Max Swift WD Statistics for last 30 years Median Start Date = Oct. 18 Median End Date = Mar. 4 Median Duration = 82 days Max Duration = 175 days

  23. ‘Worst Case’ Drought Scenario • Start in April at 80% WS Storage • 249.7 ft starting elevation for Falls/Beaverdam • Use 2002 hydrology for April & May • Use 2007-2008 hydrology for rest of the trace • 60 mgd total demand • 8 mg withdrawal from Swift • 9.5 mgd when in drought plan • No less than 36 mgd from Falls/EMJ

  24. No Drought Plan

  25. No Drought Plan – Falls Lake Elevation Bottom of Conservation Pool Sedimentation Pool Note: For this run demand / min. releases are allowed to be met even when WS/WQ accounts are depleted.

  26. Current Drought Plan

  27. Seasonal Drought Plan

  28. Seasonal Drought Plan Option 2

  29. Water Not Sold During Mandatory Conservation60 MGD demand scenario, 8 mgd Swift WD * - Mandatory conservation triggered, but no reduction in consumption expected