Week 12: Stormwater Harvesting Flashcards
What are the two components of SW as a harvestable resource?
- Identify the quantity of harvestable waster available
- Characterise WQ and matching treatment requirements to end uses
What are some drivers for SW harvesting?
- More efficient use of water on sit
- Reduced demand on potable water supplies
- Emergency WS
- Maintain natural watershed hydrology
- Health effects from drought & heat waves
- Health effects from floods
How do you quantify the available resource?
Mass balance of water
Flow in
- Rainfall frequency and magnitude
- Runoff efficiency from surface
Flow out
- Demand from potable and non-potable users
- Storage sizing and overflow frequency and magnitude
Daily capture = rainfall in - losses - water demand out + volume already stored
What are some non-potable potential reuses in NZ?
- Irrigation for gardens
- Irrigation for agriculture, orchards, etc.
- Fire-fighting
- Washing of vehicles, etc.
- Power station cooling
- Dust suppression
- Air-conditioning
- Environmental flows; stream replenishment and aquifer recharge
What potential pollutants may be present in roof runoff?
(And how could it be reused?)
Pathogens, heavy metals.
Reuse with:
- First flush diversion
- Non-potable
- Point-of-use treatment (including filtration and UV)
How could paved surface runoff be reused?
- Gross pollutants trap and litter removal
- Sediment settling and filtration
- Match treatment with end use requirements
What are the key themes for effective stormwater management?
- Effects of climate change on the stormwater system
- Stormwater as a resource instead of just a problem to be managed
- Stormwater as part of the urban water cycle
- Centrality of water and integrated catchment approach
- Nature-based solutions
- Effective flood management
- The need for WQ management
- Diverse drivers for SW management
- Acknowledging the wide array of benefits from SW management
