Outline

1. Decision Tools to Evaluate Vulnerabilities and Adaptation Strategies to Climate ChangeWater Resources Sector Sebastián VicuñaUniversity of California, Berkeley/SEICGE Hands-on Training Workshop on V&A Assessments for the Latin America and the Caribbean RegionAsunción, Paraguay, 14-18 August 2006

2. Outline • Vulnerability and adaptation with respect to water resources • Hydrologic implications of climate change for water resources • Tools/models • WEAP model presentation • Role for Multi-Criteria Analysis (MCA)

3. Effective V&A Assessments • Defining V&A assessment • Often V&A in the water sector focuses on analysis over assessment • Why? Because the focus is on biophysical impacts, e.g., hydrologic response, crop yields, land use, etc. • Assessment is an integrating process requiring the interface of physical and social science and public policy

4. Effective V&A Assessments (continued) • General questions • What is the assessment trying to influence? • How can the science/policy interface be most effective? • How can the participants be most effective in the process? • General problems • Participants bring differing objectives/ expertise • These differences often lead to dissention/ differing opinions – this is where MCA can help in prioritization

5. Effective V&A Assessments (continued) • To be valuable, the assessment process requires • Relevancy • Credibility • Legitimacy • Consistent participation • An interdisciplinary process • The assessment process often requires a tool • The tool is usually a model or suite of models • These models serve as the interface • This interface is a bridge for dialogue between scientists and policy makers

6. The Water Resource SectorWater’s “Trade-Off” Landscape

7. Natural Systems External Pressure State of System Little Control of processes Water Resources – A Critical V&A Sector • Must consider both managed and natural systems • Human activity influences both systems Managed Systems External Pressure Product, good or service Process Control services Example: Agriculture Example: Wetlands

8. Outline • Vulnerability and adaptation with respect to water resources • Hydrologic implications of climate change for water resources • Tools/models • WEAP model presentation • Role for Multi-Criteria Analysis (MCA)

9. Hydrologic ‘External Pressures’ related to Climate Change • Precipitation amount • Global average increase • Marked regional differences • Temperature increase • Change in timing of streamflows • Glacier retreat • Precipitation frequency and intensity • Less frequent, more intense (Trenberth et al., 2003) • Evaporation and transpiration • Increase total evaporation • Regional complexities due to plant/atmosphere interactions

10. Specific Pressures: Annual Runoff Change in annual runoff (A2 scenario) Arnell., 2003

11. Specific Pressures: Annual Runoff Change in annual runoff (A2 scenario) Arnell., 2003

12. Specific Pressures: Annual Runoff Change in annual runoff (A2 scenario)

13. Specific Pressures: Runoff timing, analogy to North American West Stewart et al., 2004

14. Analogy with Western North America Temperature Snow cover Topography http://plasma.nationalgeographic.com/mapmachine/index.html

15. Analogy with Western North America Snow cover Topography Temperature http://plasma.nationalgeographic.com/mapmachine/index.html

16. Refill lost Inflow spilled Specific Pressures: Runoff timing, analogy to North American West

17. Specific Pressures: Retreating glaciers Evolución del glaciar Chacaltaya (Bolivia) Retroceso del glaciar Broggi Glaciar en 1979 y 1997 Fluctuación del frente de 4 glaciares en Perú Comunicación Nacional del Perú a la UNFCCC Francou et al., 2000

18. Specific Pressures: Retreating glaciers • Meltwaters are depended upon during dry season to sustain low flow periods • Probable diminished volume and earlier timing of flows • Has implications for hydropower production, agricultural demands, and river and riparian quality and ecosystem needs

19. Specific Pressures: Extreme weather • Climate variability (El Nino/Nina Southern Oscillation) impact water availability and all economic sectors en several countries in the region (e.g. Peru, Ecuador, Central America) (IPCC 2001). • Some climate models indicate more El Nino-like climate with increased greenhouse gases concentrations (Meehl and Washington 1996; Trenberth and Hoar, 1997)

20. Specific Pressures: Extreme weather Change in extremes by the 2050s, under HadCM3 Arnell., 2003

21. Specific Pressures: Extreme weather Change in extremes by the 2050s, under HadCM3 Arnell., 1999

22. Examples of Adaptation in Water Resources • Construction/modification of physical infrastructure • Canal linings • Closed conduits instead of open channels • Integrating separate reservoirs into a single system • Reservoirs/hydro-plants/delivery systems • Raising dam wall height • Increasing canal size • Removing sediment from reservoirs for more storage • Inter-basin water transfers

23. Examples of Adaptation in Water Resources(continued) • Adaptive management of existing water supply systems • Change operating rules for reservoirs • Use conjunctive surface/groundwater supply • Physically integrate reservoir operation system • Coordinate supply/demand • Indigenous options

24. Examples of Adaptation in Water Resources (continued) • Policy, conservation, efficiency, and technology • Domestic • Municipal and in-home re-use of water • Leak repair • Rainwater collection for non-potable uses • Low-flow appliances • Dual-supply systems (potable and nonpotable) • Agriculture • Irrigation timing and efficiency • Drainage re-use, use of wastewater effluent • High value/low water use crops • Drip, micro-spray, low-energy, precision application irrigation systems • Salt-tolerant crops that can use drain water

25. Examples of Adaptation – Water Supply (continued) • Policy, conservation, efficiency, and technology (continued) • Industry • Water re-use and recycling • Closed cycle and/or air cooling • More efficient hydropower turbines • Cooling ponds, wet towers and dry towers • Energy (hydropower) • Reservoir re-operation • Cogeneration (beneficial use of waste heat) • Additional reservoirs and hydropower stations • Low head run of the river hydropower • Market/price-driven transfers to other activities • Using water price to shift water use between sectors

26. Outline • Vulnerability and adaptation with respect to water resources • Hydrologic implications of climate change for water resources • Tools/models • WEAP model presentation • Role for Multi-Criteria Analysis (MCA)

27. Tools in Water Resource V&A Studies • What tools are available to understand both water resource vulnerabilities and evaluate possible adaptation strategies? • How can stakeholders be engaged in these processes?

28. Types of Water Resources Models • Hydraulic: biophysical process models describing streamflow, flooding • Hydrology: rainfall/runoff processes • Planning: water resource systems models Which model?... What questions are you trying to answer?

29. Hydraulic Model • Critical questions • How fast, deep is river flowing (flooding effects) • How do changes to flow and channel morphology impact sediment transport and services provided (fish habitats, recreation, etc).

30. Hydrology Model • Critical questions • How does rainfall on a catchment translate into flow in a river? • What pathways does water follow as it moves through a catchment? • How does movement along these pathways impact the magnitude, timing, duration, and frequency of river flows, as well as water quality?

31. Planning Model • Critical questions • How should water be allocated to various uses in time of shortage? • How can these operations be constrained to protect the services provided by the river? • How should infrastructure in the system (e.g., dams, diversion works) be operated to achieve maximum benefit (economic, social, ecological)? • How will allocation, operations, and operating constraints change if new management strategies are introduced into the system?

32. Tools to Use for the Assessment: Referenced Water Models Operational and hydraulic • HEC • HEC-HMS – event-based rainfall-runoff (provides input to HEC-RAS for doing 1-d flood inundation “mapping”) • HEC-RAS – one-dimensional steady and unsteady flow • HEC-ResSim – reservoir operation modeling • WaterWare • RiverWare • MIKE11 • Delft3d

33. Hydraulic Water Management Model • HEC-HMS watershed scale, event based hydrologic simulation, of rainfall-runoff processes • Sub-daily rainfall-runoff processes of small catchments • Free, download from web

34. Tools to Use for the Assessment: Referenced Water Models (continued) • Planning/ hydrology • WEAP21 • Aquarius • SWAT • IRAS (Interactive River and Aquifer Simulation) • RIBASIM • MIKE 21 and BASIN

35. Current Focus – Planning and Hydrologic Implications of Climate Change • Selected planning/hydrology models: can be deployed on PC, extensive documentation, ease of use, free (or free to developing nations)… • Aquarius • SWAT (Soil Water Assessment Tool) • WEAP21 (Water Evaluation and Planning)

36. Physical Hydrology and Water Management Models • AQUARIUS advantage: Has economic efficiency criterion requiring the reallocation of stream flows until the net marginal return in all water uses is equal • Cannot be climatically driven – flows prescribed by user • Economic focus

37. Physical Hydrology and Water Management Models (continued) • SWAT advantage: Can predict effect of management decisions on water, sediment, nutrient and pesticide yields on ungauged river basins. Considers complex water quality constituents. • Rainfall-runoff, river routing on a daily timestep • Focuses on supply side of water balance

38. Physical Hydrology and Water Management Models (continued) • WEAP21 advantage: Seamlessly integrates watershed hydrologic processes with water resources management • Can be climatically driven • Based on holistic approach of integrated water resources management (IWRM) – supply and demand

39. Outline • Vulnerability and adaptation with respect to water resources • Hydrologic implications of climate change for water resources • Tools/models • WEAP model presentation • Role for Multi-Criteria Analysis (MCA)

40. Overview WEAP21 • Hydrology and planning • Planning (water distribution) examples and exercises • Adding hydrology to the model • User interface • Scale • Data requirements and resources • Calibration and validation • Results • Scenarios • Licensing and registration

41. WEAP and Planning • Provides a common framework for transparently organizing water resource data at any scale desired – local watershed, regional or transboundary river basin • Scenarios can be easily developed to explore possible water futures • Implications of various policies can be evaluated

42. Uses of WEAP • Policy Research • Alternative Allocations • Climate Change • Land Use Change • Infrastructure Planning • Capacity Building • Negotiation • Stakeholder Engagement

43. Can do High level planning at local and regional scales Demand management Water allocation Infrastructure evaluation WEAP Capabilities Cannot do • Sub-daily operations • Optimization of supply and demand (e.g. cost minimizations or social welfare maximization)

44. 40 60 A Simple System with WEAP21

45. 10 Unmet 30 70 An Infrastructure Constraint

46. 10 Unmet 30 70 IFR Met A Regulatory Constraint

47. 40 60 0 10 unmet Different Priorities • For example, the demands of large farmers (70 units) might be Priority 1 in one scenario whereas the demands of smallholders (40 units) may be Priority 1 in another

48. Different Preferences • For example, a center pivot operator may prefer to take water from a tributary because of lower pumping costs 30 10 0 90

49. WEAP is Scenario-driven • The scenario editor readily accommodates analysis of: • Climate change scenarios and assumptions • Future demand assumptions • Future watershed development assumptions

50. Futures and Scenarios: Why? • Scenarios: a systematic way of thinking about the future • To gain a better understanding of the possible implications of decisions (or non-decisions across scales and time • To support decision-making