OPTIMA: Optimisation   for Sustainable
Water Resources Management

OPTIMA: optimisation strategy

The optimisation of the WRM water resources model scenarios is a central component in OPTIMA.

The start point is defined by

  • the set of ISSUES identified by/with/from the stakeholders
  • its implementation in the baseline scenario of WRM.

The baseline scenario is extended to include a very basic economic evaluation of costs and benefits of water supply and demands met.

The basic WRM model has been extended with tools and functions for a basic economic assessment in terms of distributed:

  • costs of water supply (capital investment, operations)
  • benefits of water use (added value by demands met),
  • indirect costs (penalties for shortfalls),
  • indirect benefits (benefits for compliance),
  • flooding damages (non linear).

The economic criteria are part of the overall scenario results, and a detailed economic summary provides a sectoral assessment. This basic economic assessment provides the basis for Optimization: given a set of objectives and constraints, as well as instruments (policy measures, management alternatives, or structural, technological change) the optimization model will find the most efficient combination of measure or instruments to meet the constrain ts and further the objectives.

A multi-stage, multi-objective, multi-criteria optimization approach is used, based on the full node by node daily resolution of the dynamic simulation model, implemented as a combination of heuristics, local gradient search, a genetic programming framework, a discrete mult-criteria method combining a satisficing screening level to generate feasible and non-dominated pareto efficient solutions for a subsequent interactive discrete multi-criteria (reference point) approach to identify effcient compromise solutions.

A similar hybrid approach is under development for the STREAM water quality model.

The baseline scenario should be presented to, and discussed with, the stakeholders for each case study to incorporate their comments and suggestions as an important step towards acceptance of the eventual results.

The baseline scenario is now extended for optimisation by

  1. defining the OBJECTIVES in terms of a set of CONSTRAINTS to be met;
    (defined a hyper-region in model performance space).
  2. defining the possible measures, strategies, policies in terms of INSTRUMENTS;
    (defined a hyper-region in decision space).
For both CONSTRAINTS and INSTRUMENTS a simple questionnaire has been prepared to compile the data in a structured, consistent format:
    DRAFT questionnaire: CONSTRAINTS
    DRAFT questionnaire: INSTRUMENTS

For INSTRUMENTS, there is an on-line Water Technologies Data Base that includes both generic and location specific instruments from which initial and default values can be extracted when editing an optimization scenario:

The procedure

  1. Select a baselines scenario including economic assessment

  2. Define/edit a corresponding optimisation scenario in terms of CONSTRAINTS and INSTRUMENTS Please note that in the first level implementation, we only support NODE SPECIFIC INSTRUMENTS for DEMAND NODES.
    Use the questionnaires to compile and structure the information, refer to the manual page on Optimisation Scenarios for implementation details.

  3. Identify a set of feasible alternatives by running the optimization model, iteratively relaxing and tightening the CONSTRAINTS

  4. Eliminate dominated alternatives (from larger sets) to identify a Pareto optimal set

  5. Use the DISCRETE MULTI-CRITERIA TOOL to (interactively, possibly as a group exercise involving the stakeholders or proxies) identify and select an efficient (optimal) multi-criteria solution
OPTIMIZATION documentation and reports:
  1. Optimization Strategy
  2. Economic Evaluation
  3. Optimization Scenarios
  4. DRAFT Questionnaire: CONSTRAINTS
  5. DRAFT Questionnaire: INSTRUMENTS
  6. Water Technologies Data Base

    WaterWare Manual Pages

  7. Optimization Scenarios
  8. Discrete Multi-Criteria
  9. Constraints
  10. Instruments
  11. Water Technologies

  12. D03.1 Water Resources Modelling Tools
  13. D03.2 Basic Optimization Model
  14. D03.3 Discrete Multi-Criteria Optimization

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