Title: Decision Tools to Evaluate Vulnerabilities and Adaptation Strategies to Climate Change - The Water Resource Sector - UNFCC Climate Change Impacts and Adaptations Maputo 18 April 2005
1Decision Tools to Evaluate Vulnerabilities and
Adaptation Strategies to Climate Change - The
Water Resource Sector -UNFCC Climate Change
Impacts and Adaptations Maputo18 April 2005
- Alyssa McCluskey, University of Colorado
- and David Yates, National Center for Atmospheric
Research
2Outline
- Vulnerability and Adaptation with respect to
water resources - Hydrologic implications of climate change for
water resources - Topics covered in a water resources assessment
- Viewing water resources from a services
perspective - Tools/Models
- WEAP Model Presentation
3Effective Vulnerability and Adaptation
Assessments
- Defining Vulnerability and Adaptation (VA)
Assessment - Often VA is Analysis not Assessment
- Why?? Because the focus is on biophysical impacts
- e.g. hydrologic response, crop yields, forests,
etc. - However, Assessment is an integrating process
- Requiring the Interface of physical and social
science and Public Policy
4Effective Vulnerability and Adaptation
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 - The assessment process requires
- 1. Value
- 2. Credibility
- 3. Legitimacy
- 4. Consistent Participation
5Effective Vulnerability and Adaptation
Assessments
- VA Assessments - 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
6Water Resources A Critical VA Sector
- Often Critical to both Managed and Natural
Systems - Human Activity Influences Both Systems
Managed Systems
External Pressure
Product, good or service Process Control
Example Agriculture
Example Wetlands
7Examples 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/Hydroplants/Delivery systems
- Raising dam wall height
- Increasing canal size
- Removing sediment from reservoirs for more
storage - Inter-basin water transfers
- Adaptive management of existing water supply
systems - Change operating rules
- Use conjunctive surface/groundwater supply
- Physically integrate reservoir operation system
- Co-ordinate supply/demand
8Examples of Adaptation Water Demand
- Policy, Conservation, Efficiency, and 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
9Examples of Adaptation Water Demand (continued)
- Policy, Conservation, Efficiency, and Technology
- Industrial
- Water Re-use and Recycling
- Closed cycle and/or air cooling
- More efficient hydropower turbines
- Cooling ponds, wet tower and dry towers
- Energy (hydro-power)
- Reservoir re-operation
- Co-generation (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
10Tools in Water Resource VA Studies
- Hydrologic Models (physical processes)
- Simulate river basin hydrologic processes
- Examples - Water Balance, Rainfall-Runoff, 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
11Hydrologic Implications of CC for Water
Resources
- Precipitation amount
- Global average increase
- Marked regional differences
- Precipitation frequency and intensity
- Less frequent, more intense (Trenberth et al.,
2002) - Evaporation and transpiration
- Increase total evaporation
- Regional complexities due to plant/atmosphere
interactions
12Hydrologic Implications of CC for Water
Resources (continued)
- Changes in runoff
- Despite global precipitation increases, areas of
substantial runoff decreases - 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
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14Africa Focus ECHAM4/OPYC
15Africa Focus GFDLR30
16What 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
17Water Resource PlanningWaters Trade-Off
Landscape
18Water Resources from a Services Perspective
- Not just an evaluation of rainfall-runoff or
streamflow - But an evaluation of the potential impacts of
global warming on the goods and services provide
by freshwater systems
19Freshwater Ecosystem Services
Extractable Direct Use Indirect Use
20Tools to use for the Assessment Referenced Water
Models
- Planning
- WEAP21 (also hydrology)
- Aquarius
- SWAT
- IRAS (Interactive River and Aquifer Simulation)
- RIBASIM
- MIKE BASIN
21Referenced Water Models (continued)
- 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
22Current Focus Planning and Hydrologic
Implications of CC
- Select models of interest and available at
workshop - Why??? Free deployed on PC extensive
documentation ease-of-use - WEAP21
- SWAT
- HEC suite
- Aquarius
23Physical 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
24Physical Hydrology and Water Management Models
(continued)
- SWAT management decisions on water, sediment,
nutrient and pesticide yields with reasonable
accuracy on ungaged river basins. Complex water
quality constituents. - Rainfall-runoff, river routing on a daily
timestep
25Physical Hydrology and Water Management Models
(continued)
- WEAP21 advantage Seamlessly integrating
watershed hydrologic processes with water
resources management - Can be climatically driven
26Physical Hydraulic Water Management Model
- HEC-HMS watershed scale, event based hydrologic
simulation, of rainfall-runoff processes - Sub-daily rainfall-runoff processes of small
catchments
27Overview 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
28Hydrology 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?
29Planning 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? - How will allocation, operations, and operating
constraints change if new management strategies
are introduced into the system?
30A Simple System with WEAP21
31An Infrastructure Constraint
32A Regulatory Constraint
33Different Priorities
- For example, the demands of large farmers (70
units) might be Priority 1 in one scenario while
the demands of smallholders (40 units) may be
Priority 1 in another
34Different Preferences
30
10
- For example, a center pivot operator may prefer
to take water from a tributary because of lower
pumping costs
0
90
35Example
- How much water will the site with 70 units of
demand receive?
36Example (continued)
- How much water will be flowing in the reach
between the Priority 2 diversion and the Priority
1 return flow?
37Example (continued)
- What could we do to ensure that this reach does
not go dry?
38What Are We Assuming?
- That we know how much water is flowing at the top
of each river - That no water is naturally flowing into or out of
the river as it moves downstream - That we know what the water demands are with
certainty - Basically, that this system has been removed from
its HYDROLOGIC context
39What Do We Do Now?
40Add Hydrology
41And this is the Climate Interface
42Integrated Hydrology/Water Management Analytical
Framework in WEAP21
43The WEAP 2-Bucket Hydrology Module
Surface Runoff f(Pe,z1,1/LAI)
Sw
Dw
44One 2-Bucket Model per Land Class
45Some Comments
- The number of parameters in the model are fairly
limited and are at least related to the
biophysical characteristics of the catchment - The irrigation routine includes an implicit
notion of field level irrigation efficiency - Seepage can only pass from the lower bucket to
the river, not the other way
46This Last Point Leads to a Stylized Groundwater
Representation
47Some Comments
- The geometry of the aquifers in question are
representative, not absolute - The stream stage is assumed to be invariant in
this module - While the water table can fluctuate, it ignores
all local fluctuations
48The WEAP21 Graphical User Interface
Languages Interface Only English French Chinese S
panish
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50WEAPs Temporal and Spatial Scale
- Time step Daily, weekly, monthly, etc.
- No routing, as all demands satisfied within the
current time step - Time step at least as long as the residence time
of period of lowest flow - Larger watersheds require longer times steps
(e.g., one month) - Smaller watersheds can apply shorter time steps
(e.g., 1-day, 5-day, 10-day)
51Some Ideas onCatchment Size
- Small lt100km2
- Medium 100 to 1000km2
- Large 1000 to 10,000km2
- Very Large 10,000 to 100,000km2
52Data Requirements
- Prescribed supply (riverflow given as fixed time
series) - Time series data of riverflows (headflows) cfs
- River network (connectivity)
- Alternative supply via physical hydrology
(watersheds generate riverflow) - Watershed attributes
- Area, land cover . . .
- Climate
- Precipitation, temperature, windspeed, and
relative humidity
53Data Requirements (continued)
- Water demand data
- Municipal and industrial demand
- Aggregated by sector (manufacturing, tourism,
etc.) - Disaggregated by population (e.g., use/capita,
use/socio-econ group) - Agricultural demands
- Aggregated by area ( hectares, annual
water-use/hectare) - Disaggregated by crop water requirements
- Ecosystem demands (in-stream flow requirements)
54Example Data Resources
- Climate
- http//www.mara.org.za/climatecd/info.htm
- Hydrology
- http//www.dwaf.gov.za/hydrology/
- GIS
- http//www.sahims.net/gis/
- General
- http//www.weap21.org (resources)
55Calibration and Validation
- Model evaluation criteria
- Flows along mainstem and tributaries
- Reservoir storage and release
- Water diversions from other basins
- Agricultural water demand and delivery
- Municipal and industrial water demands and
deliveries - Groundwater storage trends and levels
56Modeling Streamflow
57Reservoir Storage
58Looking at Results
59WEAP21 Developing Climate Change and Other
Scenarios
- The scenario editor readily accommodates scenario
analysis - Climate change scenarios and assumptions
- Future demand assumptions
- Future watershed development assumptions
- Etc.
60Licensing WEAP
- User Name UNFCCC, Mozambique WEAP
WorkshopRegistration Code 1031200517844License
Expires 10/31/2005 (after which saving data
will be disabled) - After 6 months you will need to go to
www.weap21.org and register for a new license
(free for government, university, and non-profit
organizations in developing countries) - Register WEAP under Help menu and select
Register WEAP
61WEAP Hands-On Training
- Two sets of exercises
- General WEAP without hydrology
- WEAP with hydrology/climate (LATEST AND GREATEST)
- We will be training on the latest version with
hydrology and climate. - Follow along or enter the data along with me!