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IAHR/IWA Joint Committee on Urban Drainage [Committee website]
Scope
Urban drainage systems are designed to convey stormwater
runoff and sewage flows of magnitudes varying from low dry-weather
flows to floods, control fluxes of pollutants resulting from human
activities, and contribute to the general well-being of the urban
population. Furthermore, such goals should be accomplished within
the framework of integrated management of urban waters, with minimal
impacts on receiving waters, in a cost-effective way, and under
conditions of steadily increasing populations of large cities. In
view of these high demands, urban drainage is becoming a key issue
in the management of urban water resources.
The main objective of the Joint IAHR/IAWQ (International Association
for Water Quality) Committee on Urban Storm Drainage is to promote
an ecosystem approach to the planning, design and operation of urban
storm drainage. This objective supports sustainable development
of urban areas, protects their natural environment, and requires
that hydrologic, hydraulic, water quality and ecological issues
of drainage design are properly considered in a cost-effective integrated
way. Computer modelling, operational research techniques and expert
systems are standard tools for the optimisation of drainage design,
operation and their associated costs.
Every urban area has its special characteristics depending on climate,
topography, development, engineering practices, institutional and
political framework, population and economy. Thus, there are no
universal solutions which could be recommended under all circumstances
and the state-of-the-art solutions have to be examined and promoted
with respect to the specific local conditions and drainage problems.
For example, drainage problems in developing countries as well as
in the newly established democracies in Eastern Europe need special
considerations. These countries are facing great difficulties in
dealing with environmental issues under adverse economic conditions,
strong competition among various sectors for limited available funds,
and the lack of effective institutional arrangements that can resolve
these problems.
The Joint Committee organises the triennial International Conferences
on Urban Storm Drainage, related workshops and training courses,
supports regional or specialty conferences, publishes technical
reports and a comprehensive annual newsletter, and initiates research
on important issues.
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Research
Agenda
Rainfall/Runoff Processes
and Modelling: The theoretical development
of rainfall/runoff models has reached maturity and further progress
will be incremental . Current research issues include adaptation
of models for use in the realm of hydroinformatics (i.e., in conjunction
with special databases), use of radar-measured rainfall data including
moving rainstorms, efficient routing of pressurised flow in a computing
environment with full graphical support, refinement of flow quality
modelling, consideration of management options (storage and treatment
facilities), interactive, dynamic control required in real-time
control studies, and realistic modelling of sediment transport and
flow quality.
Assessment of Stormwater and CSO
Quality and Its Impacts: The traditional
approach to stormwater and CSO (Combined Sewer Overflow) quality
focused on chemical characterisation with successive emphasis on
solids, biodegradable matter, nutrients, heavy metals, hydrocarbons,
and trace organic contaminants. These chemical protocols often fail
to distinguish between toxic and non-toxic contaminants, their bioavailability
or the synergistic effects of chemical cocktails. Hence, current
research focuses on the assessment of stormwater and CSO quality
by ecotoxicity measurements. Further development of methods for
the assessment of stormwater and CSO impacts is needed, using such
concepts as biotesting, biomonitoring and biological community assessment.
Some of these methods can be also used for monitoring impacts of
thermal enhancement of urban runoff. The methodology to be developed
needs to recognise the time-dependent nature of CSO and stormwater
impacts, and the associated acute and cumulative effects.
Role of Sewer Sediment:
Sewer sediments cause numerous problems in drainage operation, including
loss of hydraulic capacity, concentration and transport of pollutants,
septicity accompanied by gas and corrosive acidity production, and
a risk of washout into the receiving waters or overloading at the
wastewater treatment plant. Furthermore, many treatment or control
options applied to CSOs and stormwater result in sediment settling
and accumulation (e.g. in stormwater ponds, CSO tanks), and the
settled sediment causes problems similar to those caused by sewer
sediment, including impacts on water quality in the overlaying water
column. Progress has been made in mathematical description of transport
of sewer sediment, either as a suspended load, or bedload. Options
for sediment control have been developed, and generally include
combinations of management practices in urban catchments, including
source controls and improved maintenance of streets and catch basins,
and in-system improvements. New research should focus on the behaviour
of cohesive sediments, and the water quality impact of contaminated
sediments.
Stormwater Management:
Best management practices (BMPs) mitigate the impacts caused by
progressive urbanisation, including increased discharges and volumes
of runoff, and export of pollutants or heat from urban catchments.
Although individual BMPs vary due to differences in climate, stormwater
characteristics, local conditions, design procedures, and modes
of operation and maintenance, international experience with BMPs
can be summarised in the following four points: (1) No single BMP
offers a universal solution to stormwater pollution; (2) BMPs should
be considered as part of the treatment train, which starts in the
catchment, continues in the collection system and a series of complementary
BMPs, and ends with in-stream measures; (3) The sustainability of
BMPs has to be ensured through proper operation, design modifications
(where required to meet the original objectives) and maintenance;
and, (4) Even though well-designed BMPs provide stormwater quantity
and quality control, visual amenities, and wildlife habitat, they
must be recognised as wastewater treatment facilities that may impact
on wildlife and cause contaminant entry into the food chain. Further
research is required on new BMPs (e.g. biotreatment systems), advanced
knowledge of BMP performance in a treatment train and under special
conditions (sensitive receiving waters, urban redevelopment, cold
climate, tropical climate), their sustainability by proper maintenance,
and their role in sustainable urban development.
CSO Control:
Perhaps the greatest innovation in CSO control is the introduction
of the integrated management approach to CSOs, considering the catchment
drainage (including the collection system), wastewater treatment
plant (WTP) and the receiving waters. In fact, only this integrated
approach to pollution control offers a true assessment of the effectiveness
of individual system components and a basis for their optimal design.
In the analysis of CSO control, several components are considered
- source controls, storage (in-line and off-line), treatment (both
central and satellite), and in-stream measures. Source controls
address both reduced influx of stormwater (e.g. by such BMPs as
infiltration) and controls of dry weather flow or solids deposits
(storage prior-to storms, reduced pollutant fluxes through regular
maintenance etc.). Temporary in-system storage can be created by
oversized storage pipes, or off-line by special storage facilities.
Recognising that the methodology for CSO control by storage is well
developed, the current research focuses on treatment processes for
CSOs, including lamellar settling, degritting with a chemical stage
for pre-treatment and flotation reactor, chemically aided settling
with microsand, and UV disinfection for protection of recreational
uses of the receiving waters.
The complexity of sewer systems, and the dynamics of flow, storage,
loads and treatment processes, make it particularly desirable to
control the sewerage/treatment/receiving water systems in real time.
Real time control (RTC) was found particularly useful in systems
with operation problems varying in type, space and time, and with
some idle capacity. Further research continues on RTC of quality
of wastewater and receiving waters, and reliable hardware.
Hydroinformatics:
Functional, spatial and temporal integration required in comprehensive
drainage studies necessitates the use of computer models. The international
modelling practice continues to be dominated by a limited number
of well-supported and continuously updated modelling packages incorporating
some aspects of hydroinformatics and merging environmental modelling
with information technology. A wide range of options available in
some of these tools allows to address comprehensive drainage/environmental
systems, including the collection system, management and control
schemes, WTPs and receiving waters. Expert system supports and RTC
simulation modules are also available. Further refinement of such
tools through new research is desirable.
Regulatory Programs:
A successful implementation of stormwater management and CSO control
requires, as a prerequisite, supporting environmental programs,
regulations and laws. Surveys of regulatory tools from several countries
indicate great variations in regulatory stance among the leading
countries in this field, implying that regulatory aspects of stormwater
management and CSO control are rather uncertain, and in some cases,
may even impede effective environmental practices. Further research
is needed into pros and cons of such current regulatory trends as
attempts to regulate according to a comprehensive assessment including
impacts, according to discharge without regard to site specific
impacts, according to the available technology without regard to
its specific effectiveness, and with or without consideration of
economic means to implement these regulations.
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Committee Officers
Leadership Team
Chair
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Prof. Peter Steen Mikkelsen
Technical University of Denmark
Institute of Environment & Resources
Bygningstorvet, Building 115
DK-2800 Kgs. Lyngby
DENMARK
tel +45 4525 1605
fax +45 4593 2850
e-mail: psm@er.dtu.dk
Bio
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Secretary
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Dr. J. Marsalek
National Water Research Institute
867 Lakeshore Road, P.O. Box 5050
Burlington
Ont. L7R 4A6
Canada
Tel. +1 (905) 336 - 4899
Fax. +1 (905) 336 - 4420
e-mail: Jiri.Marsalek@ec.gc.ca |
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Publications
IAHR/IWA Joint Committee Newsletter
Other publications - Minutes of JCUD Edinburgh 2008
- Urban Drainage Committee 2007 Report
- 5th International Conference on Urban Storm
Drainage, July 23-27, 1990, Osaka, Japan. 3 volumes. Prof. T.
Sueishi, Secretary General for 5ICUSD, c/o Dept. of Environmental
Engineering, Osaka University, 2-1 Yamadaoka. Suita 565, Osaka,
Japan.
- 6th Int. Conference on Urban Storm Drainage,
Niagara Falls, Canada, September 12-17, 1993. From Seapoint Publishing,
2880 Seapoint Drive, Victoria, B.C. V8N 1S8, Canada, Fax +1 604-472
1057.
- 7th Int. Conference on Urban Storm Drainage,
Hannover, Germany, 9-13 September, 1996. From Prof..F. Sieker,
7th ICUSD, Institut für Wasserwirtschaft, Universität
Hannover, Appelstrasse 9a, D-30167 Hannover, Germany
- Novatech’92 - Published October 1992
565 pages - Price : 200 F.F.BP 2132 · 69603 Villeurbanne
cedex · FRANCE, tel: 33 4 72 43 83 68 · fax: 33
4 72 43 92 77, e-mail: graie@urgc-hu.insa-lyon.fr
- Novatech’95 - Published June 1995, 650 pages
- Price : 200 F.F., BP 2132 · 69603 Villeurbanne cedex
· FRANCE, tel: 33 4 72 43 83 68 · fax: 33 4 72 43
92 77, e-mail: graie@urgc-hu.insa-lyon.fr
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Reports
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