Viability of Rainwater Harvesting Techniques for Johannesburg City Parks and Zoo

Transcription

1 Viability of Rainwater Harvesting Techniques for Johannesburg City Parks and Zoo 19 September 2018 R. Schmidt, R.P. Verger, K. Scott & H. Nemavhandu

2 Presentation Outline Introduction South African Guidelines Harvesting Techniques Case Studies 2

3 South African Water Context In South Africa water is a scarce commodity. Available water resources are under stress. Certain areas are frequently declared as drought areas by government. General pressure on water resources could result in future water restrictions. Irrigation of gardens and parks could be seen as a wasteful extravagance that cannot be afforded. 3

4 Project Introduction JCPZ wanted to investigate systems that use water sources such as rainfall and stormwater runoff as an asset rather than a problem. There were 27 JCPZ facilities across 7 regions: Depots Parks Zoo Nurseries Cemeteries 4

5 Project Introduction 5

6 Introduction to WSUD and SuDS Water Sensitive Urban Design - WSUD Focuses on the integration of surface water runoff/stormwater into the urban water cycle. Allows cities to become more resilient to the pressures on ageing and expensive water infrastructure Sustainable (Urban) Drainage Systems SuDS Practical affordable alternatives to stormwater management 6

7 South African Guidelines 7

8 The Urban Water Cycle Due to urbanisation, the urban water cycle has changed and there is an increase in the runoff generated from catchment areas. 8

9 JCPZ Project 9

10 Rooftop Rainwater Harvesting Rainwater harvesting is a process of capturing rainwater for re-use in a different system instead of letting the rainwater enter the stormwater system 10

11 In-Field Stormwater Harvesting In-field stormwater harvesting is used to slow down runoff to ensure maximum infiltration into the ground and recharge. 11

12 Stormwater Harvesting Techniques Underground stormwater harvesting captures stormwater runoff in underground tank that is stored for re-use 12

13 Case Studies Five (5) facilities were chosen to demonstrate the different techniques proposed throughout the project. A viability analysis for each proposed rooftop and underground stormwater harvesting technique was completed. Accumulative total cost over the life of the rooftop rainwater harvesting system was calculated and compared to the calculated accumulative water savings over life of system. 13

14 Example 1 14

15 Preliminary Cost Estimate and Viability Section Description Amount VAT 14% Total (Incl. VAT) A Section A: Springfield Depot R R R B Section B: Springfield Street Trees R R R C Section C: Pioneer Park R R R D Section D: Joubert Park R R R E Section E: Metro Park R R R Region F - Total R R

16 6 Storage Tanks Greenhouse Structure 16

17 Preliminary Cost Estimate and Viability Section Description Amount VAT 14% Total (Incl. VAT) A Section A: Marks Park Depot R R R B Section B: Zoo Lake Training Centre R R R C Section C: Johannesburg Zoo R R R D Section D: Westpark Cemetery R R R Region B - Total R R

18 1 Storage Tank Ablution Structure 18

19 Preliminary Cost Estimate and Viability Section Description Amount VAT 14% Total (Incl. VAT) A Section A: Klipspruit Depot R R R B Section B: Orlando West Park R R R C Section C: Petrus Molefe Prescient R R R D Section D: Thokoza Park R R R E Section E: Diepkloof Extreme Park R R R Region D - Total R R

20 20

21 Preliminary Cost Estimate and Viability Section Description Amount VAT 14% Total (Incl. VAT) A Section A: Johannesburg Zoo R R R Region B - Total R R

22 2 Underground Storage Tanks 22

23 Preliminary Cost Estimate and Viability Section Description Amount VAT 14% Total (Incl. VAT) A Section A: Huddle Park Nursery R R R Region E - Total R R

24 Conclusions Rooftop rainwater harvesting, stormwater harvesting and in-field harvesting was found to be viable interventions that JCPZ facilities could implement. These interventions promote conservation and reuse of water in the broader community. WSUD and SuDS provides an integrated approach that is moving away from the conventional stormwater management systems. 24

25 Recommendations Integration of rainwater harvesting and water conservation philosophies into city-wide Stormwater Runoff Control Plans. Techniques should be considered in future developments. 25

26 Thank You 26