Urban Drainage Chapter 1-3 Highlights Flashcards
Sewerage!
Combined sewer problems?
Backups and Flooding
Waste sewer problems?
illegal connections lead to exceedance
Storm sewer problems?
Urbanization,increased runoff, increased erosion, damaged ecosystem, rainfall isn’t clean (atmosphere scrubbing)
Current sewer problems?
Built at different times, residual problems, lots of different solutions needed
Four quality characteristics and effects?
- SS - block light, stops photosynthesis, kills life
- Oxygen demand - storm water can introduce life that increases this
- Nutrients - Promotes algae
- Heavy metals - toxic compound in urban runoff
Source control aim and pros?
To imporve quantity and quality
Are cost effective and site specific
Three types of collection system controls?
- Sewer Separation
- Sewer flushing
- In-system control
Sewer separation as a collection system control notes?
overflow/backup imporved
expensive
Whats is sewer flushing?
A collection system control
Summer flow leave a buildup that can be removed with flushing
What is In-system control
A collection system control
Diverts water from high to low capacity areas in real time
moderate cost for significant improvement
Five types of storage/treatment option?
- Outfall - combined
- Outfall - storm
- Interceptor capacity
- Offline storage
- Flow balancing system
What is Outfall - combined?
A storage/treatment option
needs of be small, treat lots of water quickly
unlikely to be solely used but can be used in conjunction
What is Outfall - storm?
A storage/treatment option
Detention ponds can recharge GW and remove contaminants
Can restrict outflow
Uses settlement
What is Interceptor capacity?
A storage/treatment option
Combines system for treatment to make the most of economies of scale
Larger pipe doesnt relate to reductions CSO reduction
(CSO - combined sewer overflow)
What is Offline storage?
A storage/treatment option
Diverting water to low capacity areas off the system to be pumped later