How the Loddon catchment floods • A summary of our best information and an opportunity to share it with you all. • Reach agreement on what the challenges are. • Discuss ways of working that provide multiple benefits. • Provide a platform for working together on shared solutions. 1. Summary of Catchment Overview of the River Loddon and its tributaries Catchment characteristics: Area, River length Geology, Standard Percentage Runoff (SPR), Landuse and critical infrastructure Flood Alert and warning areas Catchment Response to Rainfall Historic flooding Past experiences The Loddon and it’s tributaries • The Loddon is approx. 45 km long. • It originates from the chalk of the Hampshire Downs at Basingstoke. • It is fed from Groundwater springs. • The major Loddon tributaries are The River Hart, Blackwater, Whitewater and Emm Brook. • It joins the Thames West of Wargrave, downstream of Shiplake Lock. • Flood storage at Cove Brook and some attenuation in the gravel pits in the Blackwater Valley which take runoff from new developments. Catchment Geology Standard % Run Off (SPR) Urban and Riparian Reading Wokingham Bracknell Crowthorne Sandhurst Camberley Frimley Farnborough Fleet Basingstoke Aldershot Critical Infrastructure Six Flood Alert Areas 15 Flood Warning Areas Rainfall needed to cross threshold for varying SMDs Alert criteria: 10-15mm on a wet catchment; 30mm + on a dry catchment Warning criteria: 20-60mm on a wet catchment; Rarely exceeds Flood Warning when catchment is dry Sources/types of flooding Groundwater – e.g. Basingstoke 2000/01 Surface Water – e.g. Winnersh, Wokingham 2007 Fluvial – e.g. Lower Loddon 2013/14 Types of events • July 2007 – Summer, high intensity storms, relatively short durations. • Winter 2013/14 – Long duration, conveyor belt of active weather systems caused saturated ground. Chineham Chineham, Basingstoke – Upper Loddon – July 2007 Chineham, Basingstoke – Upper Loddon – Winter 2013/14 Chineham, Basingstoke – Upper Loddon July 2007 level = 1.3 mASD, flow = 2.9 m³/s Dec 2013 level = 0.8 mASD, flow = 1.1 m³/s July 2007 event – 54mm in 15hrs Winter 2013/14 – 52mm in 19hrs • July 2007 was largest on record at this site. • Winter 2013/14 was 4th largest on record. Tongham Tongham, Aldershot – River Blackwater – July 2007 Tongham, Aldershot – River Blackwater – Winter 2013/14 Tongham, Aldershot – River Blackwater July 2007 level = 1.8mASD, flow = 2.5 m³/s Dec 2013 level = 1.6mASD, flow = 1.9 m³/s July 2007 event – 52mm in 14hrs Winter 2013/14 – 38mm in 20hrs There is a small difference in actual levels between bankfull and property flooding. Lodge Farm Lodge Farm, River Whitewater – July 2007 Lodge Farm, River Whitewater – Winter 2013/14 Lodge Farm, River Whitewater – Winter 2013/14 Lodge Farm, River Whitewater – July 2007 July 2007 level = 0.6mASD, flow = 3.3 m³/s Dec 2013 level = 0.5mASD, flow = 2.2 m³/s July 2007 event – 52mm in 14hrs Winter 2013/14 – approx 370mm over 6 weeks July 2007 highest on record Winter 2013/14 2nd and 3rd highest on record Lodge Farm, River Whitewater – July 2007 Levels at lodge farm are affected by a sluice gate just upstream, which is operated by the pub owner (used to be a mill). This can result in a surge of flow moving downstream. Basingstoke canal can heavily overtop into the river here at times of high flows Sindlesham Mill Sindlesham, Lower Loddon – July 2007 Sindlesham, Lower Loddon – Winter 2013/14 Sindlesham, Lower Loddon July 2007 level = 1.5mASD Feb 2014 level = 1.2mASD July 2007 event – 54mm in 15hrs Winter 2013/14 – 58mm in 46hrs July 2007 highest on record Winter 2013/14 8th highest on record Sindlesham Mill Loddon Bridge Park & Ride, Cinema Winnersh Garden Centre and the George Pub (DS) of Sindlesham Mill Wokingham, Emm Brook – July 2007 Wokingham, Emm Brook – Winter 2013/14 Wokingham, Emm Brook July 2007 level = 2.3mASD, flow = 11 m³/s Feb 2014 level = 1.6mASD, flow = 4 m³/s July 2007 event – 54mm in 15hrs Winter 2013/14 – 122mm over 2 weeks July 2007 highest on record Winter 2013/14 3rd highest on record Twyford Twyford, Lower Loddon – July 2007 Twyford, Lower Loddon – Winter 2013/14 Twyford, Lower Loddon July 2007 level = 2.8mASD, flow approx (50-70 m³/s) – some bypassing of the gauge at high flows causes uncertainty in estimates Feb 2014 level = 3.1mASD, flow approx (75+ m³/s) July 2007 event – 62mm in 8hrs Winter 2013/14 – approx 300mm over 6 weeks It is also common for high Thames levels to ‘back up’ the River Loddon, delaying its peak to produce even more protracted flood conditions in the lower reaches. Swallowfield – full record back to 1987, one of the longest records we have for the Loddon Historic Flooding Date Details of Flooding Winter 2013- 6 Reported 2014 July 2007 131 properties 2006 59 properties (10 Farnham, 34 Alderhot, 15 Ash Vale) January 2003 12 properties flooded in Loddon Drive November 2000 7 properties unsubstantiated October 2000 2 properties flooded 17 properties unsubstantiated December 1999 2 properties flooded 1998 2 properties flooded February 1990 3 properties flooded Gardens of 30 properties Wokingham Aldershot Whitewater road run off 2007 (top left) Blackwater Frimley 2007 (top right) Blackwater Eversley 2007 (bottom right) Arborfield 2007 (road photo 2011) 2007 flooding The Emm Brook flooded in July 2007 when approximately 90 properties flooded in Wokingham. A further 100 were surrounded by floodwater. The Blackwater and Cove Brook catchment also flooded in 2007 affecting the areas of Farnborough, Aldershot, Ash, Ash Vale and Cove. Winter 2013-2014 Early Jan 2014 Six reported properties:- -1 in Arborfield -1 at Twyford/Wargrave area, -1 at Aldershot, -1 at Farnborough -2 at Crookham. -The Winnersh park and ride site was closed for the majority of the flood event (Dec – Feb) -The Winnersh garden centre in the Lower River Loddon alert area flooded on several occasions. -Also looks like Twyford reached its highest recorded level in February! Progress – the story so far Owen Peat - 2007 event Lindsey Newton 2009 – legal context Angela Gunnel (QMUL) 2011 – woods in rivers QMUL 2014 – 2 MSc dissertations - Flood risk and work in Blackwater Valley (Farnham Quarry) - Managing fallen trees Ongoing & completed projects Water Framework Directive & Flood Risk: working together, making space for water, working with natural process Flood Risk Management Plans Flood/Hazard Map RBMP Costs and Benefits? Do we need change? Costs? Are we turning our backs on rivers and coasts? we still flood, the future cost?, 30% topsoil (national), draining land everywhere, >90% river length modified (Thames) and over 80% waters failing ecology, Thames salmon gone = restaurants, B&Bs, tackle shops closed, membership decline, upper Thames not good ecological state, many wildlife impacts, economic benefits of a healthy environment, community cohesion, fertiliser /maintenance costs, somewhere for children to play and visitors enjoy (future), culverting, accessible blue/green infrastructure, unsafe water… This may cost tax payers a very indicative £500k to £3.8million per catchment every few years (2014 Environment Agency national catchment event). Cost £9.5million to £72.2million in the Thames basin every few years. Can we afford not work together, is this estimate right? Whats to gain? Better soils, sustainable futures, solving problems not symptoms, bridging gap between poor and rich from up-skilling, employment and outreach, we are happier and work together.. Water for life and livelihoods; a better balance between using and protecting the environment. A sense of place toenjoy Do we want to turn our back on catchments, wetlands, rivers and coasts? (Mersey Basin Campaign following 1981 riots etc) flooding scenarios suggest not. Get in touch with River Basin Management Plans, Flood Risk Management Plans and catchment delivery to help solve these for you and our future generations in your catchment Flood risk management duties & obligations National Flood & Coastal Erosion Risk Strategy Avoid damaging the environment, wherever possible work with natural processes Always seek to provide environmental benefit, as required by Water Framework Directive England Biodiversity Strategy 2020 5000ha new habitat 95% SSSIs in favourable condition WFD FCRM works must not cause deterioration to the ecology of a water body FCRM should try to find opportunities to improve the ecology of water bodies What can we do? Collaborative advantage Adopt Catchment Based Approach Work with natural processes Develop & promote good practice Design projects early with multiple benefits Spatial planning and development solutions We are all the solution Right measures in precisely the right place Aiming for multiple benefits (Semi Natural) Gravel bed and earth banks Multi Benefit Aspirational Single Focus GEP Highly Modified Channel Culverted or channelised Practicing working with natural processes Working with natural processes restores habitats and improves flood risk management by design Thames river basin district: Significant water management issues Solutions: community action, flood management and wider interest turning this... WFD Directive 2000/60/EC – framework for community action in water policy… AND DELIVERY http://ec.europa.eu/environment/water/water- framework/index_en.html To this: better soils, reducing run off managing flood risk Cotswolds and Upper Thames Source: D Martyn from Upper Thames visit Managing Thame catchment run off and diffuse pollution Source: P. Nicolet January 2014 Thames RBD Liaison Panel presentation River of Life – Thames Shillingford Source: L