R. Dittmann 1 , F. Froehlich 2 , R. Pohl 1 , M. Ostrowski 2

1. A MANAGEMENT SYSTEM FOR OPTIMIZING OPERATING RULES OF MULTIPURPOSE RESERVOIRS ALLOWING FOR BOTH EXTREME FLOODS AND ECOLOGICAL PERFORMANCE R. Dittmann1, F. Froehlich2, R. Pohl1, M. Ostrowski2 1 Institute of Hydraulic Engineering and Hydromechanics, Dresden University of Technology, Germany 2 Institute of Hydraulic and Water Resources Engineering, Technical University Darmstadt, Germany

2. OUTLINES • INTRODUCTION • HOW CAN WE ASSES THE DIFFERENT PURPOSES? • METHODS • CASE STUDY • OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES • CONCLUSIONS AND OUTLOOK INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

3. INTRODUCTION flood protection dam safety normal storage level CONFLICT OPTIMUM TRADE-OFF ecological releases downstream variability normal storage level water supply hydropower recreation INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

4. HOW TO ASSES THE DIFFERENT PURPOSES? Flood protection damage by inundation Dam safety required freeboard to avoid overtopping Water supply  water supply capacity Ecological performance  maintain the ecological variability (Hydropower) INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

5. Figure: example of ystem plan of river basin model. sub catchment reservoir river section ASSESSMENT SYSTEM: DAMAGE BY INUNDATION for each river section … 1D/2D - dynamic water level calculations Intersection of water level with digital elevation data. The flooded area is intersected with land use data and damage functions depending on inundation depth and land use applied Figure: HEC-RAS model. INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

6. Reference point dam Sector Wind direction Figure: shape and location of water surface area ASSESSMENT SYSTEM: EVALUATING DAM SAFETY Input: - wind data - reservoir specific data - shape of water surface  determining freeboard The wave run up and the wind set up is calculated according to German ATV-DVWK standard. Figure: parameter of wave run up. INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

7. ASSESSMENT SYSTEM: WATER SUPPLY We use the water supply capacity with future deficit probability of 1 %of status quo as target. ECOLOGICAL PERFORMANCE OBJECTIVE: Maintain as much as possible of the natural flow variability. The hydrologic alteration is calculated using the Indicators of Hydrologic Alteration (IHA) method (Richter et al. 1997). The IHA method uses 32 biologically relevant hydrologic attributes based upon five fundamental characteristics of hydrologic regimes: magnitude, timing, frequency, duration and rate of change. INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

8. ASSESMENT SYSTEM - SUMMARY Flood protection  f = min(Damagetotal) Dam safety f = min(Hmax) Water supply  f = min(Qext,target - Qext) Ecological performance  f = min(IHA) INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

9. X2 f2 Λ mapped by simulation Ω X1 X2 X1 f1 Objective (solution) space Λ Search (decision) space Ω MULTI-OBJECTIVE OPTIMIZATION How can we find an optimal solution with various conflicting objectives? minimize fm(x), m = 1,2,…,M subject to gj(x), j = 1,2,…,J li ≤ xi ≤ ui i = 1,2,…,N Front of non-nominated solutions which are the most effective trade-offs (Pareto-Front) INTRODUCTION ASSESMENT SYSTEM METHODSCASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

10. MULTI-OBJECTIVE OPTIMIZATION Evolutionary algorithms (EAs) use the principle of natural selection to evolve a set of solutions toward an optimum solution. Until termination criteria Initialize population P(g) INTRODUCTION ASSESMENT SYSTEM METHODSCASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

11. sub catchment reservoir river section SIMULATION TOOL Conceptual river basin management model BlueM used modules rainfall-runoff model channel routing reservoirs Complex formulation of operating rules releases can be function of Storage, time or system status releases can be scaled by system states or balances system states can be combined by +,-,*,/ or <, > or if … then .. INTRODUCTION ASSESMENT SYSTEM METHODSCASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

12. CASE STUDY Elbe river City of Dresden Reservoir Malter - flood protection - recreation - hydropower Reservoir Klingenberg - flood protection - water supply Weißeritz basin 384 km² Hmax = 905 mNN Hmin = 105 mNN Reservoir Lehnmuehle - flood protection - water supply INTRODUCTION ASSESMENT SYSTEM METHODSCASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

13. Inflow Lehnmuehle Inflow Klingenberg water supply (Qext) release OPTIMIZATION OF LONG-TERM OPERATING RULES • Objective functions • f1,2 = min(Starget- Sext) • f3 = min(Qext,target- Qext) • f4 = min(IHA) • Simulation settings • 1980 - 2002 • dt = 1d INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

14. status quo dynamic operating rule Smax Qin Qin × F(S), F(S) ≥ 1 Flood Retention Storage Starget Qmin,const Qin × F(S), F(S) < 1 Operation Storage Smin Qin Qin Dead Storage OPTIMIZATION OF LONG-TERM OPERATING RULES F(S) = decision variable INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

15. status quo Qext,target-Qext OPTIMIZATION OF LONG-TERM OPERATING RULES INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

16. OPTIMIZATION OF LONG-TERM OPERATING RULES INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

17. Figure: system plan of river basin model. OPTIMIZATION OF SHORT-TERM OPERATING RULES Applying optimization system to real time operation using precipitation and wind forecast Method: Optimization of releases through the bottom outlet • objective function space: • f1 = min(Damagetotal) • f2,3,4 = min(Hmax,reservoir) INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

18. status quo target values Pareto-optimal solution OPTIMIZATION OF SHORT-TERM OPERATING RULES no solution is valid thus target values decreased fLehnmuehle = -0.09m fKlingenberg = -0.21 m INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

19. OPTIMIZATION OF SHORT-TERM OPERATING RULES status quo target values Pareto-optimal solution valid solution INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

20. OPTIMIZATION OF SHORT-TERM OPERATING RULES status quo - 11 % target values Pareto-optimal solution valid solution • Solution 619 • damage decreased • freeboard increased - 0.38 m - 0.26 m INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

21. OPTIMIZATION OF SHORT-TERM OPERATING RULES status quo target values Pareto-optimal solution valid solution INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

22. OUTLOOK AND CONCLUSIONS • Conclusions • most effective trade offs found • help to understand the complex management • the operator can try different solutions (trade offs) a posterior • Outlook • coupling the long-term optimization with stochastic discharge model • applying Monte-Carlo-Simulation for different flood scenarios to optimize generalized short-term operating rules INTRODUCTION ASSESMENT SYSTEM METHODS CASE STUDY OPTIMIZATION OF LONG- AND SHORT-TERM OPERATING RULES CONCLUSIONS AND OUTLOOK

23. A MANAGEMENT SYSTEM FOR OPTIMIZING OPERATING RULES OF MULTIPURPOSE RESERVOIRS ALLOWING FOR BOTH EXTREME FLOODS AND ECOLOGICAL PERFORMANCE R. Dittmann1, F. Froehlich2, R. Pohl1, M. Ostrowski2 1 Institute of Hydraulic Engineering and Hydromechanics, Dresden University of Technology, Germany 2 Institute of Hydraulic and Water Resources Engineering, Technical University Darmstadt, Germany