URBAN HYDROLOGY

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URBAN HYDROLOGY Powered By Docstoc
					URBAN HYDROLOGY
 URBAN FABRIC

RUNOFF PROCESSES AND
 DRAINAGE CHANNELS
Hardened surface promotes rapid surface runoff
Runoff channeled along roadside flows rapidly downhill
Many streams in urban areas are at least partially channelised
The Kuils River on the Cape Flats is typical of urban channels
URBAN STRUCTURE

RUNOFF SURFACES AND
DRAINAGE NETWORKS
Panorama of Grahamstown:
 note proportion of hardened v. vegetated surfaces and
degree of connectivity between runoff surfaces
and the main stream channel.
How does the hydrological response change in different
areas of the town?
Riparian zone of Blaukrantz river;
how connected is the river to the build up area?
Upper catchment of small urban stream
POLLUTION SOURCES
Litter in an urban stream; pollution derived from the catchment
surface
Sewage works below King Willliamstown and Zwelitscha:
Note Buffalo River in trees to the left of the sewage ponds.
Saline outflow from the Da Gama textile factory
DOWNSTREAM IMPACTS
Algal growth in Laing Dam
Water hyacinth in Laing Dam
  FLOOD PLAIN
TRANSFORMATION
The modern flood plain of the Ebro River, northern Spain
Zaragoza town in early days:
impact on river channel and flood plain is localised
Modern Zaragoza: impacts now extensive
Flood walls protect urban development
REGIONAL IMPACTS
Gareip dam: source of water for Port Elizabeth and Grahamstown
WATER SUPPLY TO
 GRAHAMSTOWN

				
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posted:9/23/2011
language:English
pages:27