CGE Training materials - VULNERABILITY AND ADAPTATION Assessment CHAPTER 6

1. CGE Training materials - VULNERABILITY AND ADAPTATION AssessmentCHAPTER 6 Water resources

2. Chapter Objectives and Expectations • Having read this presentation, in conjunction with the related handbook, the reader should: • Have an understanding of potential hydrological impacts of climate change on water resources and how to assess those impacts • Be able to identify the various stakeholders involved in the water sector and their potential influence on the water sector and water planning • Have gained an overview of methods, tools and data required for conducting impact assessment • Have gained knowledge on different adaptation options available for water resources • Be familiar with different inputs and outputs of the WEAP model using a hypothetical river basin, and how such outputs are used in impact assessments.

3. Outline • Hydrologic implications of climate change for water resources • Drivers and potential impacts • Methods, tools and data requirements to assess vulnerability in water resources • Adaptation responses by systems and sectors

4. Effective V&A Assessments • 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.

5. 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.

6. Effective V&A Assessments (continued) • To be valuable, the assessment process requires: • Relevancy • Credibility • Legitimacy • Consistent participation • It is 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.

7. Hydrologic Implications of Climate Change • Precipitation amount: • Global average increase • Marked regional differences • 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.

8. Hydrologic Implications of Climate Change (continued) • Changes in run-off • Despite global precipitation increases, areas of substantial run-off decrease • Coastal zones: • Saltwater intrusion into coastal aquifers • Severe storm-surge flooding • Water quality: • Lower flows could lead to higher contaminant concentrations • Higher flows could lead to greater leaching and sediment transport.

9. Hydrologic Implications of Climate Change (continued) Fifteen-model mean changes in (a) precipitation (%), (b) soil moisture content (%), (c) run-off (%), and (d) evaporation (%). To indicate consistency of sign of change, regions are stippled where at least 80% of models agree on the sign of the mean change. Changes are annual means for the scenario SRES A1B for the period 2080-2099 relative to 1980-1999. Soil moisture and run-off changes are shown at land points with valid data from at least ten models. Source: Bates et al. (2008)

10. Africa Example – ECHAM4/OPYC

11. Africa Example – GFDLR30

12. Impacts: Soil Moisture • Decreases in the sub-tropics and the Mediterranean region • Increases in East Africa, central Asia and some other regions with increased precipitation • Decreases also occurring at high latitudes, where snow cover diminishes.

13. Impacts: Run-off and Stream Flow • Significant regional variation in run-off and stream flow: • Run-off reduced in southern Europe • Run-off increased in south-east Asia • Stream flows in high-latitude rivers increase • Stream flows in the Middle East, Europe and Central American tend to decrease.

14. Impacts: Coastal Zones • Increased inundation and coastal flooding causing salinization of groundwater and estuaries • Changes in the time and volume of freshwater run-off affecting salinity, sediment and nutrient availability • Changes in water quality may come as a result of the impact of sea level rise on storm-water drainage operations and sewage disposal in coastal areas.

15. Impacts: Water Quality • Higher water temperatures may exacerbate many forms of pollution • Changes in flooding and droughts may affect water quality through sediments, nutrients, dissolved organic carbon, pathogens, pesticides and salts • Sea level rise is projected to extend areas of salinization of groundwater and estuaries.

16. Impacts: Groundwater • Surface water variability directly tied to groundwater variability in unconfined aquifers • Increased abstraction from population growth and reduced surface water availability will likely result in declining groundwater levels.

17. Impacts: Demand, Supply and Sanitation • Climate change will likely add further stress to water service issues including: supply, demand and governance.

18. Natural systems External pressure State of system Little control of processes Water Resources – A Critical V&A Sector • Often critical to 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

19. What Problems Are We Trying to Address? • Water planning (daily, weekly, monthly, annual): • Local and regional • Municipal and industrial • Ecosystems • Reservoir storage • Competing demand • Operation of infrastructure and hydraulics (daily and sub-daily): • Dam and reservoir operation • Canal control • Hydropower optimization • Flood and floodplain inundation.

20. The Water Resource Sector Water’s “Trade-Off” Landscape

21. Water Resources from a Services Perspective • Not just an evaluation of rainfall-run-off or streamflow • But an evaluation of the potential impacts of global warming on the goods and services provided by freshwater systems.

22. Freshwater Ecosystem Services Extractable; Direct Use; Indirect Use

23. Ideal Water Situation • Adequate quantity • Appropriate timing of its availability • Appropriate quality. What do we do to achieve this desired water situation?

24. A summary of Climate Change Impacts on Water Resources

25. Mismatch Between Water Demand and Supply • Attributes of the mismatch: • Adequate Quantity • Appropriate timing of its availability • Appropriate quality • Reasonable price • What impacts would these mismatches have on: • Environment • Economy • Society • Adaptation issues: • What are the most effective measures to reduce this mismatch.

26. Adaptation Responses by Systems and Sectors • Agriculture and food security, land use and forestry • Human health • Water supply and sanitation • Settlements and infrastructure • Economy: insurance, tourism, industry, transportation • Gender.

27. Water resource adaptation in agriculture • Adoption of varieties/species with increased resistance to heat shock and drought • Modification of irrigation techniques • Adoption of water efficient technologies to “harvest” water and conserve soil moisture • Modification of crop calendars, i.e. timing or location of cropping activities • Implementation of seasonal climate forecasting.

28. Water Resource Adaptation in Human Health • Malnutrition and water scarcity may be the most important health consequences of climate change • Health impact assessments often reveal the opportunities to embed the health effects of any adaptation strategy in the water sector, such as those in water supply and sanitation.

29. Water Supply and Sanitation Adaptation • Construction of new storage reservoirs • Using alternative water sources, such as groundwater or desalination • Rainwater harvesting as well as controlled reuse • Use of decentralized systems.

30. Adaptation in Settlements and Infrastructure • Adaptive responses are likely to be very expensive in built up areas. Adaptation should be carefully considered in the context of: • Settlements in high-risk locations, such as coastal and riverine areas, due to flood and storm damages and water quality degradation as a result of saline intrusion • Settlements whose economies are closely linked to a climate-sensitive water-dependent activity, such as irrigated agriculture water related tourism.

31. Examples of Adaptation – Water Supply • 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.

32. Examples of Adaptation – Water Supply (continued) • Adaptive management of existing water supply systems: • Change operating rules • Use conjunctive surface/groundwater supply • Physically integrate reservoir operation system • Coordinate supply/demand.

33. Water Supply Adaptation – Policy, Conservation, Technology • Domestic: • Municipal and in-home re-use • Leak repair • Rainwater collection for non-potable uses • Low flow appliances • Dual supply systems (potable and non-potable) • Agricultural: • Irrigation timing and efficiency • Lining of canals, closed conduits • 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.

34. Water Supply Adaptation – Policy, Conservation, Technology • Industrial: • 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.

35. Water Problem Solving Approach • Diagnosing: • Identifying entry point • Identifying lead agency • Stakeholder analysis • Establishing a coordination and facilitation committee • Situation analysis: Social including gender and poverty; economic; environmental including ecosystem approach. • Visioning: • Problem tree analysis: Cause and effects of root problem • Objective Tree Analysis: Main cause is converted into objective of strategy Identifying entry point.

36. Water Problem Solving Approach • Strategising: • Scenario development: • A selection of possible development options: Framework identification; content identification; strategy preparation. • Planning: • Plan preparation: • Action plan and budget • Responsibility matrix • Scheduling • Monitoring targets and indicators.

37. Water Problem Solving Approach • Implementing: • Preparation of workplans and budgets and general administrative and financial management • Capacity development • Institutional strengthening • Strengthening the enabling environment: Recalibrating policy and legal instruments for water resources management • Data collection. • Monitoring and Evaluation (M&E), and documentation: • M&E using indicators • Documentation of lessons learned and best practices.

38. Methods, Tools and Data Requirements

39. Key Elements of the Analysis Which policy makers, planners, investors, implementers, water users, affected stakeholders, researchers, civil societies should be involved?

40. The River System

41. Rivers, Watersheds and Aquifers

42. Water Use Sectors Issues What is the current water demand and supply situation? How might climate change development influence water demand and supply? How might socio-economic development influence water demand and supply? How might socio-economic and climate change development influence water demand and supply? Fishery Recreation Navigation

43. Linking Supply with Demand Issues What are the hydrologic linkages? What are the current and future implications of these linkages?

44. Tools in Water Resource V&A Studies • Hydrologic models (physical processes): • Simulate river basin hydrologic processes • Examples – water balance, rainfall –run-off, lake simulation, stream water quality models • Water resource models (physical and management): • Simulate current and future supply/demand of system • Operating rules and policies • Environmental impacts • Hydroelectric production • Decision support systems (DSS) for policy interaction.

45. Tools in Water Resource V&A Studies (continued) • Economic models: • Macroeconomic: • Multiple sectors of the economy • General equilibrium – all markets are in equilibrium • Sectoral level: • Single market or closely related markets (e.g., agriculture) • Company level • Farm-level model (linear programming approach) • Microsimulation

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

47. Referenced Water Models (continued) • Operational and hydraulic: • HEC • HEC-HMS – event-based rainfall-run-off (provides input to HEC-RAS for doing one-dimensional flood inundation “mapping”) • HEC-RAS – one-dimensional steady and unsteady flow • HEC-ResSim – reservoir operation modelling • WaterWare • RiverWare • MIKE11 • Delft3d.

48. Current Focus – Planning and Hydrologic Implications of Climate Change • Select models of interest (Deployed on PC; extensive documentation; ease of use): • WEAP21 • SWAT • HEC suite • Aquarius

49. Physical Hydrology and Water Management Models • AQUARIS advantage: Economic efficiency criterion requiring the reallocation of stream flows until the net marginal return in all water uses is equal • Cannot be climatically driven.

50. Physical Hydrology and Water Management Models (continued) SWATmanagement decisions on water, sediment, nutrient and pesticide yields with reasonable accuracy on ungauged river basins. Complex water quality constituents. • Rainfall –run-off, river routing on a daily time step.