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

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

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

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

What should we be doing:-

• Provide systems that are safe and cheap to maintain

• Protect our Natural Environment for future generations

• They should be teaching aids for the local residents

• Get Residents of Oxfordshire involved!!