Table 2 Variations of main scenarios with probability and consequence parameters
Main scenario | Variations—consequence impact | Scenario specifics | Potential consequence | Building blocks |
|---|---|---|---|---|
1. Climate change | a. Positive impact b. Low negative impact c. Medium negative impact d. Major negative impact | Increase in precipitation intensity. | - Capacity reduction in combined sewers (WW) - More frequent basement flooding (WW) - Generally increased hydraulic strain (WW) | Climate change |
Frost and temperature patterns will change, including frosting and thawing cycles. | - Increase in blockages of pipes and reduced reliability (WW) - Reduced reliability (DW) - Change in failure rates (DW) | |||
Increased sedimentation and particle runoff to water sources (DW). | - Sedimentation problems in pipes (DW) | |||
Drought which causes ground movement due to lowered groundwater table | - Increase in blockages of pipes and reduced reliability (WW) - Reduced reliability (DW) - Change in failure rates (DW) | |||
2. Demographics Population change | a. Low growth b. Medium growth c. High growth d. Reduction | Increase in impervious areas and increased household wastewater discharge | - Increased hydraulic strain on networks (WW) | Demographics |
Population growth | - Need to increase hydraulic capacity (WW) | |||
Increased water demand | - Need to increase hydraulic capacity (DW) - Change in water quality and reduced corrosion problems (DW) | |||
Population reduction and water demand reduction | - Water quality problems and increased corrosion (DW) | |||
3. Delivered service | a. As today b. Higher in someareas c. Higher in all areas | Stricter regulations (WW). | - Less acceptance for pollution discharge (WW) - Less acceptance for water leakages (DW) - Less acceptance for failures (DW) | Governing and regulating aspects Service level delivered to end users Ambition of the water utilities |
Public awareness | - Less acceptance for basement flooding in residential housing (WW) - Less acceptance for storm water flooding in urban areas (WW) - Lower risk acceptance (WW/DW) - Less acceptance for discoloured water (DW) - Less acceptance for shut down of water supply (DW). | |||
4. Technologic and methodical development | a. As today b. Higher efficiency and more green solutions c. Higher efficiency, more green solutions, and more durable rehabilitation methods | More efficient and higher quality renovation methods | - Simplifying rehabilitation and improving lifetime expectancy of renovated pipes (DW/WW) | Technological and methodological development |
Higher quality pipe materials | - Improving lifetime expectancy of new pipes (DW/WW) - Rehabilitation methods with longer life spans (like replacement) will be more environmental friendly which facilitates its use (WW/DW) | |||
Higher share of green solutions in the rehabilitation market | - Reduced hydraulic strain on pipes (WW) | |||
Implementation of Low Impact Development (LID) solutions in storm water management | - Facilitates a higher degree of rehabilitation rates due to reduced costs (WW/DW) | |||
Higher degree of coordination between water, sewer and roads in rehabilitation | - Facilitates a higher degree of use of replacement with longer life span than renovation methods (WW/DW) | |||
5. Resource capacity | a. Severely reduced capacity b. Reduced capacity c. As today Higher capacity | Lack of personnel | - Lag in rehabilitation (WW/DW) | Economy Organizational capacity |
Lack of expert knowledge | - Lag in rehabilitation and/or poorly managed and executed rehabilitation (WW/DW) | |||
Insufficient financing in renewal | - Lag in rehabilitation (WW/DW) - Implementation of less than optimal, but low cost, solutions (WW/DW) | |||
High inflation | - Reduced capacity for investment in rehabilitation, which leads to lag in rehabilitation and/or implementation of less than optimal solutions (WW/DW) |