CASE STUDY 11 : FLOODING (LOCAL SCALE) CASE STUDY - HOE STREAM Flashcards
LOCATION
WESTFIELD AREA, TRIBUTARY OF RIVER WEY
SOUTH WOKING, SURREY
SOUTH EAST ENGLAND
, NORTH EAST OF MAYFORD
CAUSES - 4 POINTS
URBANISATION
DEFORESTATION
GLOBAL CLIMATE CHANGE
RAINFALL INTENSITY AND DURATION
STRATEGIES - HARD ENGINEERNG
BUNDS/EMBANKMENT TERRACES - BLEND WITH ENVIRONMENT, BUILT UP THE FLOOD PLAIN AND STRENGHTENED THE SIDES OF THE CHANNEL AND PROVIDE EXTRA CAPACITY FOR FLOOD WATER. GRASS NEEDS CUTTING.
FLOOD WALLS - DEVELOPED BY SPECIALIST PROTECTS 200 PROPERTIES IN THE BARNSBURY ESTATE FROM FLOODING BY BEING A BARRIER. EXPENSIVE TO BUILD BUT VERY EFFECTIVE.
DATES
COMPLETED IN 2012
REASONS FOR SCHEME
PUT IN TO PROVIDE FLOOD DEFENCES FOR UP AT 1 IN 100 YEAR FLOOD EVENT.
COST
£44 MILLION
WHOLE AREA REGENERATED AS WELL AS THE FLOOD DEFENCE PUT IN.
REGENERATION OF THE AREA
NEW COMMUNITY FACILITIES NEW PARKLAND AREAS AND RECREATION GROUND FOOTPATHS CLEARING UP OF THE TOXIC TIP SITE CREATION OF NEW WILDLIFE HABITATS WIDENED ROAD AND NEW BRIDGE (HIGHER SO ROAD DOES NOT GET FLOODED)
STRATEGIES - SOFT ENGINEERNG
AFFORESTATION - CHEAP AND ATTRACTIVE HOWEVER, NOT AS EFFECTIVE AND TAKE LONG TIME TO GROW.
OVERSPILL PONDS - ARTIFICIAL PONDS - PROVIDE EXTRA CAPACITY FOR FLOOD WATERS AND ARE ATTRACTIVE HABITAT FOR ANIMALS
STAKEHOLDERS
LOCAL COMMUNITY GROUPS eg 7TH WOKING SCOUTS
NEW SECONDARY SCHOOL BUILT TOO
COMMUTERS - LOTS OF TRAFFIC DISRUPTION DURING BUILDING OF THE NEW BRIDGE
BARNSBURY RESIDENTS -
LOCAL ENVIRONMENT GROUPS - NEW TREES WERE PLANTED AND THE OVERSPILL PONDS ATTRACT WILDLIFE
CAUSES OF FLOOD - URBANISATION
- WOKING BECOMING A BUILT UP AREA OF LONDON AND NOT COUNTRYSIDE. INCREASING NEED FOR HOUSING WHICH IS MORE IMPERBMEABLE SURFACES = MORE SURFACE RUN OFF. QUICKER SURFACE RUN OFF = LESS WATER INFILTRATING SOIL.
CAUSES OF FLOOD - DEFORESTATON
- 15 YEAR PLAN TO REMOVE 100ACRES OF WOODLAND AND HENCE WOKING PARK AREA HAS BEEN DEFORESTED DESPITE ARGUEMENTS FROM COUNCILLOR. TREES SLOW DOWN THE COURSE OF WATER GETTING TO RIVER. VEGETATION INTERCEPTS RAINFALL AND REDUCED SURFACE RUN OFF
CAUSES OF FLOOD - RAINFALL INTENSITY AND DURATION
AFFECTS RIVER’S DISCHARGE AS THE AMOUNT OF RAINFALL WILL AFFECT WHETHER THE SOIL IS SATURATED AND IF NO INFILTRATION AND MORE SURFACE RUN OFF . IN 2014 SOUTH EAST ENGLAND SAW IT’S WETEST WINTER SINCE 1910
CAUSES OF FLOOD - GLOBAL CLIMATE CHANGE
- INCREASES IN GLOBAL MEAN TEMPERATURES ARE CHANGING WEATHER PATTERNS AND FOR UK LEADING TO HIGHER RAINFALL INTENSITY AND HIGHER VOLUME = SURGE IN AMOUNT OF DISCHARGE AND SURFACE RUN OFF