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The Projects - Coy Pond Gardens 2002-2004

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Flooding Issues at Coy Pond Gardens

On 13th October 2004 33.8mm of rain fell in a 24-hour period - that's more than the entire rainfall for the month of May (32.7mm) or June (28.3mm) that year. 

In fact there have been only 11 incidents of 30mm or more rain falling on the catchment in the last eight years [more local rainfall data]

13th October 2004

The pictures below illustrate the catastrophic effect that such heavy rain has where it issues from the 2.5km culverted section into Coy Pond Gardens; all were taken between 12:35 and 13:05 pm on 13.10.06:

Above: The control structure in the new bridge is operating at full capacity

Above: The new wooden footbridge in front of the culvert is completely underwater

Above (looking south) & below (looking north): The stream has filled the floodbasin, although there is still a narrow dry border thanks to the terracing created when the floodbasin was created.

Above & below: water levels fall off dramatically during less heavy rainfall (in about 10 minutes)

The gardens further downstream fared little better:

Above & below: both bridges downstream of Bourne Pools are completely impassable

Below: At the steps leading from Coy Pond Road 

Above and below: the lower end of Coy Pond Gardens underwater

It's rainfall events such as these that combine with a rising water table to give the almost permanently boggy ground in the lower reaches of Coy Pond Gardens.

28th June 2005 - it's believed that 14mm of rain fell in just one hour on a June afternoon bringing flash floods to Bournemouth & Poole, just four days after a night of tropical-style rain, thunder and lightning storm

The results were spectacular too see, and had wide-spread effects with local homes and commercial premises inundated by floodwater. 

The Bourne Stream burst its banks and stormwater swamped the public gardens from the railway embankment at Bourne Pools right through to the Lower Gardens in Bournemouth.

Bourne Pools (below) bursting at the seams

And (below) the footpath completely impassable

In September 2006 the Partnership started work on a project which could help to alleviate some of the flooding at Coy Pond Gardens. 

At Bourne Valley Park, some 2.5km upstream of the gardens, the stream has been released from its culvert and 3,500 cu.m. of stormwater storage created:

May 2007 - the latest SUDS scheme at Bourne Valley Park:

Photos below courtesy of local resident, Glynis Northwood-Long

Alderney Rec weir, May 2007

Above: the 2m deep stream channel beyond the bridge, filled with floodwater, acts as a 'detention basin'. 

When it reaches full capacity water flows through the weir and down the lower channel and a second detention basin (below).

Alderney Rec weir, May 2007

From Bourne Valley Park water flows in an underground culvert for 2.5km, discharging at Coy Pond Gardens.

SUDS - 4 Options • Ecological Surveys • Flooding Issues • Pollution Issues • Water Quality

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