Category: flood
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A River Runs Through It. Proposed Gatwick Northern Runway expansion and impacts on the River Mole
(Note: this was written by me in October 2023) ABSTRACT Overall, the Gatwick Northern Runway Project has schemes that could improve on existing flood risk mitigation and water quality management. Several schemes seek to improve the local river environment and access to it. Examples of welcome improvements include the Museum Field FCA, the de-culverting of…
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Levelling up? Uneven patterns of recent rainfall highlight characteristic river response and signpost future management strategy in the River Mole catchment.
Thunderstorms tracked across the Lower Mole basin in the early hours of 29 June 2023 but they largely missed the Upper Mole. The storms were much heavier over the Lower Mole to the north of the catchment over places like Molesey and Esher. In contrast the Upper Mole catchment to the south of Dorking received…
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From deluge to drought… building resilience in the River Mole catchment by “spongifying” the landscape!
In this post, I review flood management in the Mole catchment as it is now, including other nature based schemes; I also look at the benefits of Natural Flood Management and how they can contribute to flood control, reduction of pollution and increase resilience to drought; I also review NFM techniques, including benefits and potential…
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Rainfall intensity rules River Mole runoff, to a point.
Bit of a cryptic title but this follows my previous post on how our flashy local river responds to rain. Two recent contrasting rainfall events occurred at the tail end of this wet November and it struck me how the Mole responded quite differently to these. So in this post I have drawn up hydrographs…
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River Mole: flashy by nature?
The River Mole is a flashy river! This means levels rise quickly after rain falls over the catchment. The hydrograph below shows the River Mole discharge at Gatwick gauging station rising quickly after a heavy squall line passed over the catchment, dropping 11mm in less than 1 hour. This is not outside normal rainfall but…
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A video following the Mole downstream from source to Thames!
I’ve made a video to celebrate our local river by following it downstream from source to the confluence with the Thames. It highlights the challenges our river faces and picks up some of the key places and features (obviously not all… and slightly skewed to where I know best which is the upper mole). I…
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The 1968 Mole Flood
The worst recorded flooding in the River Mole was in 1968 when a rare 1:200 year storm caused rainfall to exceed 100mm in 24 hours and a staggering discharge over 240 cumecs in the Lower Mole (see extract below). For comparison, the average discharge of the River Thames in London is 65 cumecs and the average September…
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2013 Flooding on the River Mole: causes, impacts and management
The River Mole is a modest lowland river in SE England that rises near Rusper in the wooded hilly heartland of the Surrey / Sussex Weald, near Crawley and Horsham. The Mole and its tributaries flow broadly north, through Crawley, around and under Gatwick airport, before meandering through mostly rural countryside to Dorking. The Mole…
The Mole Story 