Science that should help find solutions: Hydrology and water resources

1. Science that should help find solutions: Hydrology and water resources Matthew McCartney

2. SRP-Basins • Entry points • Understand and consider resource variability in basin management • Invest in water infrastructure • Allocate and manage basin water and land to raise productivity, improve equity and safeguard ecosystem services • Introduce and consistently follow the principles of benefit sharing • Pay attention to the political economy of policy selection

3. 1. Understand and consider resource variability in basin management Needs: Data Basic understanding of hydrological processes

4. Characterize variability Seasonal variation Flow duration curves Flood frequency analyses Low flow analyses Assurance levels volumes of water that can be guaranteed with different degrees of certainty Rainfall, River flows and Groundwater

5. Trend analyses Not just total rainfall/flow but other significant variables (e.g. no. of rainy days; onset of rainy season) Regional significance not just individual stations India – significant rainfall trends (1951-2007) Ghana - For variables exhibiting regionally significant trends the number of individual stations with significant trends is less than 50% of total stations

6. Changes in demand • Changes in demand vary between years (particularly irrigation) and experience trends • Future development is inherently uncertain so must think about scenarios Olifants: Simulated changes in demand

7. Link to economics Evaluate the financial “cost” of failing to deliver water in different sectors Olifants – cost of failing to deliver water for different return periods and different development scenarios

8. 2. Invest in water infrastructure Must be able to evaluate range of storage options combined within a basin

9. Need and effectiveness Storage need Storage Effectiveness RRV criteria Reliability: the probability of the storage to meet demand Resilience: the speed of recovery of storage from failure Vulnerabilitya measure of the cumulative maximum extent of failure

10. Role of natural infrastructure Some ecosystems act like natural reservoirs and regulate flows: • decrease wet season flows • increase dry season flows Method whereby natural flow regulating impacts can be quantified and incorporated in decision-making Means that basins with both built and natural infrastructure can be considered in decision-making Monthly flow upstream and downstream of the Luswishi floodplain

11. 3. Allocate and manage basin water and land to raise productivity, improve equity and safeguard ecosystem services Ecosystem Services The Challenge To devise strategies that support human development (improve livelihoods) and simultaneously safeguard ecosystem services How to achieve wise use of basins in any specific social, economic and ecological setting?

12. Getting it wrong • Inappropriate agricultural practices…. not only destroy other ecosystem services (regulating, supporting and cultural) but also undermine agriculture Degraded landscapes in Ethiopia (photos by Adrian Wood)

13. Natural basin Intensively utilized basin Striking a balance Hydropower Hydropower Hydropower Provisioning services Regulatory services Cultural services Supporting services Crops Crops Crops Industrial Industrial Industrial Regulation of water balance Regulation of water balance Regulation of water balance Multifunctional “green” basin Recreation Recreation Recreation Erosion control Erosion control Erosion control Nutrient cycling Nutrient cycling Nutrient cycling Climate regulation Climate regulation Climate regulation Soil formation Soil formation Soil formation

14. Linking ecosystem services and water productivity Developing a framework to effectively compare parallel benefits is extremely difficult. One possible approach is expanding the water productivity concept

15. Environmental flows Many methods for estimating EFs – ranging from simple low confidence desktop approaches to complex resource intensive multi-disciplinary studies Need methods that are applicable to developing countries but for which we can be confident about the results and link to livelihoods Tis Issat Falls, Blue Nile

16. 4. Introduce and consistently follow the principles of benefit sharing Evaluating upstream-downstream interactions • Lake Tana • Impact of dam/irrigation development on lake levels and • Implications for: • Environment • Non-ag sectors (e.g. hydropower) • Livelihoods

17. Cumulative impacts Need to think about cumulative impacts in space and time Need methods where these can be quickly determined

18. 5. Pay attention to the political economy of policy selection Hydrological/Resource methods - identify the costs, benefits and risks (for whom and when) associated with particular courses of action. To be useful findings must be fed into decision-making processes. Must think about how results are presented and to whom and when.

19. Thank you

20. Finding solutions: think out of the box Harvest the floods: the subsurface solution • Chao Phraya Basin Desk Study • MAF = 12,248 Mm3y-1 • 3,300 Mm3y-1 discharge to sea harvestable • Cost <$1 billion • Additional 270,000 ha of irrigation • $150 My-1 income to smallholder farmers • No precidents. Technical studies; studies of institutional arrangements Current situation With managed aquifer recharge

21. Aim: maximizing productivity/benefits All change needs to be considered in relation ecosystem services and trade-offs