Analysis of Floods

A comparison of circumstances leading to flooding at Bear Mead. Flooding occurs when the rate of flow down the River Stour exceeds about 80 cu metres/sec. This flow is produced by run-off from a catchment area of 1,300 km2. High run-off can occur if the water table is high with steady rain, or low with excessive rain, or combinations in between. An important factor is the height of the water table above the river height ,Z, caused by earlier rainfall. If Z is negative, the ground will absorb rain without runoff. If positive most of the rain will run straight into the river.

Floods since July 03: 2003 none | 2004 none | 2005 Dec 3 | 2006 Nov 26, Dec 31 | 2007 Mar 6 | 2008 Jan 16, Mar 17, Dec 15 | 2009 Feb 10, Nov 30, Dec 4, Dec 9 | 2010 none | 2011 none | 2012 Apr 27, May 01, May 02, Jul 08 Nov 21,23,25,26 2013 Jan 14, Jan 29

Eyemead UNFLOODED. 100 acres of floodplain between the River Stour and the A31, 2 kms West of Wimborne in Dorset. Looking South from Pamphill. Other degrees of Flood

Eyemead FLOODED. 100 acres of floodplain, flooded to a depth of about 40 cms (16,000 tons). Looking South from Pamphill. Other degrees of Flood

Floods since July 2003

Floods 17,18 14,29 Jan 2013 Z=+20, 28 mm rain in 4 days then 53 mm in 5 days.

123456789012345678901234567890123456 FLOOD-17

12345678901234 FLOOD-18

Flood 16 22-28 Nov 2012 Z=+30, 91mm rain in 7 days. [Note: Flooded for 7 days]

12 FLOOD-16

Flood 15 10 Jul 2012 Z=+20, 100 mm rain in 7 days.

123456789012 FLOOD-15

Floods 12,13,14 27 Apr - 02 May 2012 Z=+10, 140 mm rain in 17 days.

12345678901234567890123456789012 FLOOD-12 -13

-14

No Floods for 29 months

Floods 9,10,11 01-10 Dec 2009 Z=+60, 107mms rain in 11 days [Note: Watertable above 220 for 14 days]

FLOODS-9, 10, 11

Flood 8 10 Feb 2009 Z=+40, 39mms rain continuous [Note: previous melting snow drove water table to 220]

FLOOD-8

Flood 7 15 Dec 2008 Z=+40, 20mms rain in 1 day [Note: heavy rain & floods in W Dorset & E Devon]

FLOOD-7

Flood 6 17 Mar 2008 Z=+49, 24mms rain in 2 days

FLOOD-6

Flood 5 16 Jan 2008 Z=+30, 95 mms rain in 12 days

FLOOD-5

Flood 4 6 Mar 2007 Z=+30, 58 mms rain in 5 days

FLOOD-4

Flood 3 31 Dec 2006 Z=+30, 54 mms rain in 3 days

FLOOD-3

Flood 2 26 Nov 2006 Z=+10, 120 mms rain in 10 days

FLOOD-2

Flood 1 3 Dec 2005 Z=+10, 30 mms rain in 2 days

FLOOD-1

No Floods for over 29 months

Measured, compiled, hand-coded, and copyright © 2013, John Palmer, All Rights Reserved.