This document discusses the relationship between climate change, precipitation patterns, and water management infrastructure. It presents three key points: 1) Climate change is expected to change precipitation patterns and decrease water resources in some areas like the Mediterranean, exacerbating existing water variability and scarcity issues. 2) As climate variability increases, dam and reservoir dimensions may need to be increased to reliably capture more variable water resources over time. Optimization methods can help determine the most cost-effective infrastructure dimensions. 3) Case studies in Algeria and Greece model how dam storage capacity and operations may need to change to maintain reliable water supply under different climate models and scenarios of precipitation and demand changes. The optimal storage level increases with greater precipitation changes and

1. CIRED laboratory
HYPATIA NASSOPOULOS, PATRICE DUMAS, STEPHANE HALLEGATTE
CLIMATE CHANGE, PRECIPITATIONS AND WATER MANAGEMENT
INFRASTRUCTURES
Water in Africa:
Hydro-Pessimism or Hydro-Optimism?
CEAUP, 2-3 October, Porto Portugal
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2. Mediterranean r.+ CC + Water = ?
7% world’s population
3% world’s water resources,
temporal and spatial variability
Climate change: change in
precipitation patterns, decrease
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3. Climate change and Hydraulic infrastructures
Present: stationary climate without taking into consideration climate change
When variability increases, increasing dam and reservoir dimensions allows to
capture more inter-annual variability until all is captured
How to keep a satisfactory level of reliability by optimizing the available resources?
Small mountainous catchments in Algeria and Greece
Sensitivity analysis of climate model choice on the hydraulic infrastructure’s
Optimal Dimension
Cost Benefit Analysis of different dam heights under climate change optimal
storage capacity
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4. Simulation of dam operation
Simulate inflows under different constant precipitation and temperature
changes by using local run-off monthly coefficients
Simulate dam operations (monthly) using simple rules:
Serve fixed demand
Overflow when inflow exceeds storage capacity
If available water less than demand, consider that demand can not be
reliably satisfied
Compute demand at 95% reliability for different inflow changes
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5. Inflow and demand under climate change
IPCC models output under A2 scenario linear trends of
precipitation change
Hypothesis of demand adapting to the available resources
Each year the annual demand at 95% reliability for this inflow
change is used
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6. Investment decision, Cost Benefit Analysis
Cost: Rock fill dam, trapezoidal section, local height/volume geometry
Benefits:
Dt Demand at 95% reliability with climate change as computed previously
Water price per m3 p
Discount rate ρ
NPV= (∑(1/(1+ρ))t p Dt 0.95)-Cost
For each IPCC model, demand at a fixed level of reliability,water price
and discount rate, we find the storage capacity which maximises the NPV
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7. Results
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8. Results
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9. Results
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10. Results
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11. Conclusions
Optimal storage capacity increases with increasing
precipitations
Optimal storage capacity increases with increasing variability
For the 12 models precipitation and variability are correlated
Wide range of optimal storage capacity
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12. obrigada!
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