Post on 15-Dec-2015
Management of Surface Water in Severe Weather Conditions
from the Highway
GORDON HUNT
COUNTY DRAINAGE ENGINEER
for
OXFORDSHIRE COUNTY COUNCIL
Can the Existing Systems Cope
• In the intense storms we are experiencing
• NO
• The old drainage systems can not cope
Problems we are experiencing due to the intense storms
• Blocked Gullies
• Silted pipes
• Silted soak away’s
• Blocked bore holes
• Overgrown and blocked ditches
• These are expensive to maintain
• So they don’t get done regulary
What can Oxfordshire do about it
• Find more money – Where ?
• Encourage – self help
• Residents to rake leaves off gullies outside their propertys
• Encourage local Flood Groups – to check,:-
• local problems, walk ditches, identify problems early
• Give support to these Groups
What can the Highway Authority do to help
• Think outside to box!!
• Change the type of drainage we are installing
• Design systems that are cheap to maintain
• Or require minimum maintenance
• Be creative
Porous Pavements - is one way
• All new estate roads, but not on Bus Routes
• It stores water in storms – reducing flows down stream
• Have chambers built into water storage so Contractors can pump water up to maintain Developments Planting Scheme in drought conditions
Severe Weather
• Yes – severe weather can mean drought conditions as well
• We need water to water all the trees and plants that are planted every year on road schemes, developments, schools etc.
Swales and Grips• Over the edge drainage – cheap to maintain• Grips with kerb droppers – safe and cheap• Wide swales – so cars can drive through them –
safe• Have filter drains under the grass – linking
swales • Construct check damns to slow the water flows
down• Swales hold more water than pipes
Ponds
• Good water storage
• Looks good on developments
• Flat side slopes – safe
• No fencing or hard concrete headwalls
• Use natural materials
• Vegetation grows quick – no need to plant
• Cheaper to maintain than Box Culverts