Download Impact of urbanisation on water flow regimes and quality

Impact of urbanisation on water flow
regimes and quality
Dr. M. Hutchins and Dr. T. A. Warnaars
contributions from James Miller, Scott McGrane and Xiaowei Liu
NERC Centre for Ecology & Hydrology
The UK Centre of
excellence for research
in the terrestrial &
freshwater environments
and their interactions
with the atmosphere
Our goal is to deliver solutions for
environmental problems to achieve
sustainability
Our Science Strategy
• Over 350 Scientists and support staff
• UK National monitoring
schemes including
– Environmental Change
– Greenhouse Gases
– Water Flood/Flow
– Air Quality
– National Land use
• POLLCURB investigates
how water pollution
relates to change in urban
areas, in particular that
brought about by
population growth.
Results will provide
predictions of future water
resources to help inform
decision-making.
• Focus on Thames basin
Collaborators:
POLL-CURB PROJECT
• 3-year £900k project funded by the UK NERC
Changing Water Cycle programme (May 2013 start)
• Changes in Urbanisation and its Effects on Water
Quantity and Quality from Local to Regional Scale
• UK population will increase by 16% in next 20 years.
Compare 2050 Thames water quality to present day?
Wallingford
50
Increase in number of days per year
in days per year
Increaseconditions
having undesirable
45
1. Climate model
(Had-RM3)
40
35
2. Rainfall-runoff
model
(Future Flows)
30
25
20
15
An increase in number of days per year
having undesirable water quality by 2050
(due to drier, sunnier, warmer summers)
•
Moreover, this assumes no change in
population. Urban growth will put greater
stress on water resources…
•
The projections will be refined in POLLCURB
0
DO
BOD
Temp
3. Water quality
model
(QUESTOR)
•
10
5
Models linked together in
sequence to evaluate
effects of climate change
chl-a
-5
Case studies: towns of Swindon and Bracknell
S
S
S
S
Treated sewage effluent
Environmental data acquisition
a) 1975*
b) 1990
c) 2007
d) 2011
• Remote sensing imagery captures land-use change.
• Water flows (since 1960s) and quality (since 1980s)
• 2 years monitoring of: (i) logged hydroclimatology
(15-min rainfall and discharge) and (ii) telemetric
hourly water quality (YSI multi-parameter sonde).
• Water quality: pH, turbidity, temperature,
conductivity, ammonium and dissolved oxygen. Also,
sonde used for monthly water quality surveys at 16
other sites
Research approaches
• Monitoring urban streams
in 2 rapidly growing towns.
• Satellite land-cover data
and Ordnance Survey maps
will train cellular automata
land-use change models.
• Water flow and water
quality data will train biophysical models (rainfallrunoff, urban water
management, suspended
sediments, channel
hydraulics/water quality).
Part of
Swindon
From land cover change, a metric of
fractional impervious cover drives a
rainfall-runoff model to quantify
changes in hydrological regime
Urban water management modelling
•
•
•
Water demand
Urban drainage,
water supply and
water quality
(SWMM)
Wastewater
treatment,
discharges to
rivers (SSDIM –
has been tested
in small Chinese
urban basins e.g.
Shenzhen River)
Research questions and model development
1. Has long-term urbanisation significantly altered the flow regime?
2. Can urban river pollution be determined by land cover data,
measures of infiltration capacity and rainfall patterns readily
available from national-level datasets?
3. How do water temperature, residence time and channel hydraulics
influence the fate of pollutants downstream of urban areas?
• Simplified upscaling to whole Thames basin.
• At basin scale future scenarios will be defined by projections of
population growth, urban development, water demand
management, water treatment and climate inputs.
• Future scenarios assessed using the meta-model and QUESTOR.
Model representation of River Thames (QUESTOR)
Model drivers: (1) Flow,
temperature and quality data
in (a) tributaries (b) effluents
from sewage works,
(2) Solar radiation (3) Weirs
(4) Abstractions
Upstream QUESTOR boundary
CEH weekly water quality (2009 - )
Major urban areas outside London
2
Simulates
flow routing,
and pollution
retention
and release
in short river
reaches (c. 3
km) on a
daily basis.
1
3
4
SWINDON
LONDON
7
5 6
8
9
BRACKNELL
Tidal limit
20 km
Other acknowledgements
OTHER CONTRIBUTORS
Thomas Kjeldsen (Bath)
Soon-Thiam Khu (Surrey)
Simon Dadson (Oxford)
Clare Rowland, Iwona Cisowska, Luisa Doughty, Yan
Weigang (CEH)
June Jones, Matt Loewenthal (EA)
Steven Loiselle, Charlotte Hall, Richard Sylvester
(Earthwatch)
Banyu Putro (Royal Holloway)
Contributing to Water Quality Legislation - WFD
examined how multiple effects
impact on managing
freshwater ecosystems
Integrated project on adaptive
strategies to mitigate impacts of
climate change on European
freshwater ecosystems
Restoring river ecosystems in Europe:
the REFORM project will provide
tools to support cost-effective
implementation of restoration
measures and monitoring
WATCH: A Global Project
•To integrate modelling of the
water cycle into global and
regional climate models
•evaluate how the global water
cycle and its extremes respond to
future drivers of global change
•develop a modelling and data
framework to assess the future
vulnerability of water as a
resource
Estrogen prediction in Yellow River using CEH GWAVA model
• What are the likely impacts of
increased urbanisation on river
estrogen concentrations?
• Currently ~50% of population STP
connection
• Natural flows successfully
simulated in 1950s. More recent
simulations highlight need to
refine representation of water
demand.
Lijin
Lanzhou
Tongguan
TONGGUAN
Estimated flow
1800
1400
5.22%
27.1% 26.7%
1600
Flow (m3 /s)
• Gwava: 50x50 km grid resolution. 9 flow gauges
for model testing. Estrogen concentrations in
2008
• Estrogen loads based on: (i) Chinese effluent
observations, or, (ii) excretion and removal
rates based on UK data
2.14%
RSD: 20.9%
4.6%
12.2%
1200
Measured flow
10.6%
18.3%
1000
800
600
400
200
0
1952
1953
1954
1955
1956
Year
1957
1958
1959
1960
Thank You