LIST OF TABLES

v

LIST OF FIGURES

vi

1.

INTRODUCTION AND OBJECTIVES

1

2.

WHAT IS MEANT BY DECISION SUPPORT SYSTEM?

4

3.

DSS DESIGNED TO SUPPORT THE SEA IN IMPLEMENTING THE NATIONAL WATER ACT (1998)

6

4.

INFORMATION ACQUISITION

7

5.

PROBLEM STRUCTURING

8

6.

DEFINING THE PROBLEM

9

7.

INFORMATION REQUIREMENTS

12

7.1

Information Required to Set Up a Catchment Management Strategy

12

7.2

Information Required to Assess Individual License Applications

15

7.3

Modelling Requirements

16

7.3.1

Generic modelling requirements needed to foster stakeholder interaction

17

7.3.2

Modelling requirements in the DSS designed to support the CMA

17

7.3.3

Modelling requirements to assist in compiling the CMS and associated allocation plan

17

7.3.4

Current water use in the catchments

19

7.3.5

Modelling projected water demands and developmental constraints

20

7.3.6

Modelling required for the assessment of individual license applications

21

7.3.7

Assessment of modelling methodologies currently used by DWAF

22

7.3.8

Assessment of models used by DWAF in terms of the DSS design

24

7.3.9

Selection of hydrological model to use in WMA DSS

33

7.4

Water Quality Considerations

36

7.4.1

Background in terms of the National Water Act (1998)

37

7.4.2

Data required to address water quality issues

38

7.4.3

Modelling water quality issues

39

7.4.4

Models currently used for water quality modelling

41

7.4.5

SWOT analysis of water quality modelling and monitoring in a WMA

43

7.5

Data Requirements for the SEA-DSS

44

7.5.1

Invariant data requirements

45

7.5.2

Variant data requirements

45

7.5.3

Ecological data requirements

46

7.5.4

Economic data requirements

47

7.6

Basis and Requirements for a Common Database

47

7.6.1

Temporal and spatial scale considerations

50

7.6.2

Database requirements for the DSS

50

8.

DEVELOPMENT OF AN INTERACTIVE, GENERIC, HYDROLOGICALLY FOCUSSED SCENARIO GENERATOR

54

8.1

Responsibilities and Challenges Faced by the DWAF SEA

54

8.2

A Generic, Hydrologically Focussed Scenario Generator

57

8.3

Delineating Water Use Activities

59

8.3.1

Delineating water use activities: Hydrological considerations

59

8.3.2

Delineating water use activities: The location of the water use activity

61

8.3.3

Delineating water use activities: Environmental considerations

62

8.3.4

Delineating water use activities: Social considerations

62

8.3.5

Delineating water use activities: Economic considerations

62

8.4

Water Demand and Supply Scenarios

65

8.4.1

Direct control of water demand via water use licenses and license conditions

65

8.5

Scenarios Relating to Engineering Structures and the Operating Rules Associated to Engineering Structures

66

8.6

Technical Challenges Faced by the Development of the SG: Stand-Alone and Linked Scenarios

67

8.7

The Use, Potential Limitations and Opportunities of the Scenario Generator

68

9.

EVALUATION OF ALTERNATIVES

70

10.

ANALYSIS OF DECISION SUPPORT SYSTEMS

73

10.1

Literature Review of the Different DSSs Used in South Africa

68

10.2

Analysis of DSSs Available

77

11.

DESIGN IMPLEMENTATION PLAN

79

11.1

Database Structure

79

11.2

Processing Component

82

11.2.1

Scenario generator and attribute builder implementation plan

83

11.2.2

Modelling tools required in the processing phase of the implementation plan

84

11.3

Visualisation Component

87

12.

CONCLUSIONS AND RECOMMENDATIONS

89

13.

REFERENCES

95

14.

REVIEW OF THE PROPOSED SEA-DSS IN THE LIGHT OF GÖRGENS (2001) GUIDELINES FOR WATER RESOURCES MODELLING PROCEDURES TO SUPPORT WATER MANAGEMENT INSTITUTIONS

98

Table 1

Summary table of the attributes of models used by DWAF

34

Table 2

Types of information required by a potential SEA client. The column on the right comments on how a scenario-generator developed in ArcView may be used to meet these information requirements

59

Table 3

Examples of water using activities and some important considerations

60

Table 4

An example of the division of water use into categories necessary for the scenario generator to permit specific scenarios to be generated which are consistent with the objectives of the National Water Act (1998)

63

Table 5

Summary table of attributes of the DSSs analysed in this document

77

Table 6

Review of the proposed SEA-DSS in comparison to the Görgens (2001) report

98

Figure 1

Schematic representation of the decision making process (adapted from Görgens and Jewitt, 2000 and Stewart et al., 2000)

5

Figure 2

The problem structuring phase of the decision support framework

8

Figure 3

Criteria to be considered for the assessment of water use licenses

9

Figure 4

Considerations and information requirements needed for the development of a catchment allocation plan

12

Figure 5

A complex approach to database management

49

Figure 6

A simple approach to database management

49

Figure 7

Major components of the DSS design

79

Figure 8

Some of the invariant and variant data requirements for the DSS

81

Figure 9

The processing component of the DSS

83

Figure 10

Economic modelling component of the DSS

85

Figure 11

The visualisation component of the DSS and the linkages to the database and processing components

87