Table 7 Summary of model assumptions and simplifications on model outputs
From: A model to assess tephra clean-up requirements in urban environments
| Assumption/simplification | Implication for model output | ||
|---|---|---|---|
| Under estimation | Over estimation | Negligible | |
| Removal volumes | |||
| No other waste streams (e.g., construction/demolition) | x | ||
| No clean-up within 500 m of vent due to level of destruction | x | ||
| Remobilisation of deposits not considered | x | ||
| Potential for deposits to infiltrate storm water system not considered | x | ||
| 100% of tephra on surfaces removed | x | ||
| Asset sub-categories not considered (e.g., building/road typologies) | x | ||
| Long lasting eruption/multiple fallout events | x | x | |
| Clean-up duration | |||
| Clean-up vehicles can operate on tephra covered roads | x | ||
| Traffic not considered | x | ||
| Time moving tephra from properties to pick-up points not considered | x | ||
| Potential restrictions on truck routes to disposal sites not considered | x | ||
| Worker breaks and vehicle maintenance not considered | x | ||
| Shortest trip duration to contingency plan disposal sites must be used | x | ||
| Duration for scoping and planning not considered | x | ||
| Disposal site operational capacity not considered | x | ||
| Street sweeper travel inefficiencies (e.g., moving around parked cars) | x | ||
| Assume rational operators within system | x | ||
| Heavy machinery quantity scaled for truck fleet requirements | x | ||
| Experience level of clean-up managers not considered | x | ||
| Remobilisation not considered | x | ||
| Rainfall not considered | x | x | |
| Time it takes material to accumulate not considered | x | ||
| Clean-up cost | |||
| Existing solid waste and disaster waste contracts | x | x | x |
| Coordination and volunteerism costs | x | ||
| Business disruption costs | x | ||
| No post-disaster price escalation | x | ||