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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