The River Mersey
The River Mersey narrows to 0.7 miles wide between the Liverpool landing stage on its east bank and the Woodside and Seacombe landing stages on its west bank. The River has the world’s fourth highest tidal range with up to 10 meter high spring tides and 7 meter high neap tides.
Due to the narrowing of the river from over 3 miles wide in parts and the size of the tides, speeds of water behind all three landing stages can regularly get up to 7 Knots (8MPH). This causes numerous under currents around all three of the landing stage areas and can sweep a person entering into the water away in a few seconds. Tidal Range = difference between Low Water and High Water Old Liverpool Landing Stage As can bee seen in the photo above there are many obstructions around the three stages that can often be hidden by the varying heights of the tide that can easily trap a person or drag them underneath.
Hydrology in the River Mersey is varied and dynamic due to different water pressures and meteorological effects through the tidal cycle. That is to say an area of relatively calm water can change within 30 minutes to two foot standing waves and boils. Further to this large items of flotsam and jetsom i.e. sofas, trees, gas bottles are in the river moving at up to 8mph with the tide.
Water temperature in UK waters is at its coldest in March at around 8’C and warmest in September at around 10’C. Casualties in the River Mersey can go sub surface after immersion in approximately 3-4 minutes due to cold water shock/exhaustion/entrapment/tidal effect.
Considerations
• State of tide
Flooding (incoming) or Ebbing (outgoing)
Speed of flow
Sea state (height of waves)
Depth of water / visibility ( unable to see 30cm sub surface on certain tides)
• Weather
Direction / strength of wind – onshore may be difficult for boat handling
Visibility/Fog
• Lighting
Low levels of ambient light at
Due to the narrowing of the river from over 3 miles wide in parts and the size of the tides, speeds of water behind all three landing stages can regularly get up to 7 Knots (8MPH). This causes numerous under currents around all three of the landing stage areas and can sweep a person entering into the water away in a few seconds. Tidal Range = difference between Low Water and High Water Old Liverpool Landing Stage As can bee seen in the photo above there are many obstructions around the three stages that can often be hidden by the varying heights of the tide that can easily trap a person or drag them underneath.
Hydrology in the River Mersey is varied and dynamic due to different water pressures and meteorological effects through the tidal cycle. That is to say an area of relatively calm water can change within 30 minutes to two foot standing waves and boils. Further to this large items of flotsam and jetsom i.e. sofas, trees, gas bottles are in the river moving at up to 8mph with the tide.
Water temperature in UK waters is at its coldest in March at around 8’C and warmest in September at around 10’C. Casualties in the River Mersey can go sub surface after immersion in approximately 3-4 minutes due to cold water shock/exhaustion/entrapment/tidal effect.
Considerations
• State of tide
Flooding (incoming) or Ebbing (outgoing)
Speed of flow
Sea state (height of waves)
Depth of water / visibility ( unable to see 30cm sub surface on certain tides)
• Weather
Direction / strength of wind – onshore may be difficult for boat handling
Visibility/Fog
• Lighting
Low levels of ambient light at