FLOODING FROM RIVERS, SEA AND SUFACE WATER
High means that each year, this area has a chance of flooding of greater than 1 in 30 (3.3%).
Low means that each year, this area has a chance of flooding of between 1 in 1000 (0.1%) and 1 in 100 (1%).
Medium means that each year, this area has a chance of flooding of between 1 in 100 (1%) and 1 in 30 (3.3%).
Very low means that each year, this area has a chance of flooding of less than 1 in 1000 (0.1%).
FLOOD ZONE
Flood Zone 2 - land assessed as having between a 1 in 100 and 1 in 1,000
annual probability of river flooding (1% – 0.1%), or between a 1 in 200 and 1 in
1,000 annual probability of sea flooding (0.5% – 0.1%) in any year.
Flood Zone 3 - land assessed as having a 1 in 100 or greater annual probability
of river flooding (>1%), or a 1 in 200 or greater annual probability of flooding
from the sea (>0.5%) in any year.
This map is for land-use planning. If you are planning a development, you will need to undertake a more detailed flood risk assessment to show how the flood risk to the site, or elsewhere as a result of proposed changes to the site, can be managed as part of your development proposal.
GROUNDWATER ZONES
Inner zone (Zone 1): minimum radius of 50 metres
Outer zone (Zone 2): minimum radius of 250 or 500 metres
Outer zone - subsurface activity only (Zone 2c)
Total catchment (Zone 3): Defined as the area around a source within
which all groundwater recharge is presumed to be discharged at the
source
WATERSHED
River Weaver formerly joined the River Mersey at Weston Marsh, but since the construction of the Manchester Ship Canal, begun in 1887, it has flowed into the canal, from where surplus water enters the
Mersey by the Weaver sluices, just upstream of the junction.