Drainage and Flood Risk - New Development | South Norfolk Council

Drainage and Flood Risk - New Development

You can find advice relating to flood risk and drainage matters below.

These factors and guidance should be considered with any new developments, and addressed in any planning application. 

Just click on the green arrows for more information

Minor Development – Flood Risk

The National Planning Policy Framework and its Technical Guidance require that the Local Planning Authority only considers development in flood risk areas where informed by a site-specific Flood Risk Assessment that identifies all sources of flooding and demonstrates how these risks will be managed

Advisory Note 1 - Minor Development Flood Risk

Standing Advice

You need to follow the Environment Agency’s standing advice if you’re carrying out a flood risk assessment for a development classed as vulnerable in flood zone 2.

Advisory Note 7 - Minor Development Standing Advice

Householder and Minor Extensions – Flood Risk

The National Planning Policy Framework and its Technical Guidance require that the Local Planning Authority only considers development in flood risk areas when informed by a site-specific Flood Risk Assessment or follow the Flood Risk Standing Advice and demonstrates how those risks will be managed. 

Advisory Note 2 - Householder and Minor Extensions

Standing Advice

You need to follow the Environment Agency’s standing advice if you’re carrying out a flood risk assessment for a development classed as a minor extension in flood zones 2 & 3.

Advisory Note 6 - Householder and Minor Extension Standing Advice

Major Development – Surface Water Drainage

Norfolk County Council in its role as Lead Local Flood Authority (LLFA) is the statutory consultee for all major development. 

Advisory Note 4 - Major Development Surface Water Drainage

Minor Development – Surface Water Drainage

It is important to make sure that the most sustainable method of surface water drainage is implemented in line with the National Planning Policy Framework and Building Regulations.  The surface water drainage hierarchy should be followed with all available options being considered and the most sustainable techniques used wherever appropriate. 

Advisory Note 3 - Minor Development Surface Water Drainage

Non-Mains Foul Drainage

The first option should always be connection to a public sewer.  Only when connection to the public sewer is demonstrated not to be feasible (in terms of cost and/or practicality), should a package treatment plant incorporating a combination of treatment processes be considered.  If this is also shown not to be feasible, then you should refer to the general planning guidance on the hierarchy of drainage solutions.

Advisory Note 5 - Minor Development Foul Drainage

Land Drainage

If you own or are developing land bordering an ordinary watercourse (stream, ditch, culvert,) you may be a riparian owner or joint riparian owner.  Riparian owners have certain rights and responsibilities established in common law over many years.

Advisory Note 8 - Land Drainage

Dirty Water & Vehicle Wash-Down Water

If your proposal generates dirty water or polluted run-off as part of its operations you must not allow this to directly drain into surface waters or groundwater. 

Advisory Note 10 - Dirty Water and Wash Down Water

Poringland & Framingham Earl

The Poringland and Framingham Earl areas have been identified as having a predominantly clay geology, with pockets of sands and gravels.  When combined with a high or perched water table, this can lead to many areas being unable to dispense with surface water via soakaways.

Advisory Note 9 - Poringland and Framingham Earl