Role of Water Sensitive Urban Design in Urban Water ...cdn.cseindia.org/userfiles/Somnath Sen.pdfDr....

Dr. Somnath Sen, Department of Architecture and Regional Planning, IIT Kharagpur, INDIARegional Workshop on “ Urban Water Management”, Dec 20-21, 2013, at IHC, New Delhi

Role of Water Sensitive Urban Design

in

Urban Water Management

------sustainable options


Experts Comment

“ The 19th Century was a century of empires;the 20th century was a century of nationstates and the 21st century will be acentury of cities” ----

Wellington E. Webb, Former Mayor, Denver, Colorado, USA


Effect of Urbanisation

Mark Fletcher, (Nov. 2011) ,Water cities in Transition, International Conference, Amsterdam


Global Water Scarcity, Demand and Usage

Source: UN World Water Development Report


Effect of Urbanisation on Water

URBANISATION

POPULATION DENSITY INCREASES

BUILDING DENSITY INCREASES

GROUND WATERPOLLUTION

STORMWATER QUALITYDETERIORATES

GR.WATERRECHARGE REDUCES

RUNOFF VOLUMEINCREASES

RECEIVING WATER QLTY.DETERIORATES

BASE FLOW REDUCES

PEAK RUNOFF RATE INCREASES

WASTE DISPOSAL

WATERBORNEWASTE INCREASES

URBAN CLIMATECHANGES

IMPERVIOUS AREAINCREASES

WATER RESOURCES PROBLEMS

POLLUTION CONTROL PROBLEMS

FLOOD CONTROL PROBLEMS

DRAINAGE SYSTEM MODIFIED

FLOW VELOCITY INCREASES

LAG TIME & TIME BASED REDUCED

WATER DEMAND RISES


Link between population density and availability of Freshwater

Densely populated portion of India receives heavy rainfall causing Urban Flooding


There is a water crisis today. But the crisis isnot about having too little water to satisfy ourneeds. It is a crisis of managing water so badlythat billions of people—and the environment—suffer badly.

-- World Water Council

Points to Ponder


Water Related Impact


Climate Related Impact


The Urban Water related Crisis

Dynamic use of Water in Urban Centers.

Incapability of U.L.B. to respond to challenges.

Supply infrastructure not in pace with increasing consumption.

Gap between supply and demand.

Heavy Exploitation of ground water and surface resources.


Climate Change and Its Impact

Prediced Effects include :

Reduced Flow and levels in rivers posing problem of water intake

Declining ground water level inviting subsidence of settlements

High water surface temperature thereby increasing evaporation rate

Higher outside temperature with increased use of water and A/C

Lower quality of source of water resulting increase cost of treatment

Shift the Emphasis from water supply city to water-sensitive cities


Urban Water Management Transitions Framework– Brown,2009

Source: Wong and Brown,11th International Conference on Urban Drainage, Edinburgh, Scotland, UK, 2008


The Old Paradigm The Emerging Paradigm

Storm water is a nuisance.. Storm water is a resource.

Demand is a matter of quantity. Demand is multi-faceted.

One use. Water follows one-way path fromsupply, to a single use, to treatment anddisposal to the environment.

Reuse and reclamation. Water can be usedmultiple times, by cascading from higher to

lowerquality needs, and reclamation treatment forreturn to the supply side of infrastructure.

Gray infrastructure. Green infrastructure.

Bigger/centralized is better Small/decentralized is possible

Limit complexity and employ standard solutions.

Allow diverse solutions.

Integration by accident. Physical and institutional integration by design.

Characteristics of ‘old’ and ‘emerging’ paradigms of urban water systems:

Towards a new approach – Sustainable water management


What has not been looked into, so far?

To what extent rainwater available in an area could be effectivelyutilised with appropriate technology and environmental safeguard soas to partially meet the domestic as well as non-domestic waterdemand in local areas.

To what extent storm water could be appropriately utilised for aneffective flood control management under emergency situations.

To what extent ground water resources should be utilised so as not toexceed the recharging possibilities, and also to avoid the detrimentalenvironmental consequences of overexploitation of ground water.

To what extent the grey water , in absence of sewerage system, couldbe properly managed for non-domestic purposes, so that the untreatedwater do not pose serious health concerns.

How Urban Development might be planned and executed in a mannerso as to lower the hydrological impact of urbanisation and presentopportunities for improved water management.


What is meant by Water Sensitive Urban Design

• Rainwater• Stormwater• Potable mains drinking water• Greywater (water from the bathroom sinks, shower, and

laundry)• Blackwater (toilet and kitchen) (sewer)•Groundwater

WSUD marks a shift in thinking towards integrated water management where all water streams are considered a resource.

The integrated water management cycle considers:


WSUD Guiding Principles

Optimising the use of rain that falls on the city catchment

Reducing the storm water runoff and manage flooding

Prevent flash flood related damage

Reducing the amount of potable water demand for the city

Incorporating water related social and ecological objectives into our design (Mouritz, M. 2000)

WSUD Elements•Source Control, to retain the small frequent rainfall events at the individual lot level.•Conveyance Control, to detain the large events of rainfall at neighbourhood level.•Discharge Control, for conveying the extreme rainfall events at the watershed level.


Factors affecting strategies for WSUD

There are numerous ways to incorporate WSUD in a redevelopment project to meet water targets. Strategies depend on factors such as:

• Individual site conditions (e.g. location, geography)• Building function and occupancy (e.g. residential, commercial,

industrial)• Development or redevelopment scale• Water use and demand (e.g. garden irrigation demand,

industrial use)• Water sources available, including local climate (rainfall

seasonality)• On-site catchment area (roof and surface)• Urban landscape design (architectural and landscape).


Benefits of WSUD

• Increased water conservation• Improved storm water quality, therefore improved water

quality in waterways, bays and catchments• Increasing rainwater harvesting and ‘natural’ treatment

alternatives.• Providing an adoption measure to address climate change

impacts such as flooding and heat island effect.• Replacement of pipes with natural elements for drainage,

such as wetlands• Enhanced aesthetics through increased vegetation, aquatic

elements and landscaping• Flood mitigation by slowing down water movement

through urban areas to streams.


Technical Solutions Water Sensitive city

OBJECTIVE

Efficient Use of Water Supply

Water metering

Leak detection program

Pressure management

Adoption of water saving tips

Water pricing


OBJECTIVE

Maintain ground water supply

Reduce extraction

Increase urban recharge

Rain water harvesting

Increase vegetation cover

Impervious control in residential zone

Sustainable options


Domestic Water Use pattern in Medinipur Town,WB

Location ofStudy

Total Number of

Buildings

Number ofHouseholdsurveyed

Average Household

Size

Average Water Use

Lit./cap./day

Kitchen andBathing UseLit./cap/day

Toilet,WashAnd other

Lit./cap/day

Habibpur 64 49 4.27 70 34 36

Kamarara 57 50 6.02 81 39 42

Boxibazar 24 24 7.46 93 42 51

Patnabazar 70 70 5.47 88 40 48

MitraCompound

44 44 4.5 121 60 61

BidhanNagar

37 37 4.5 112 54 58


Rainfall Spectrum Analysis for Medinipur Town

Inferred Parameters

Very Wet

Wet Year Above Normal

Normal Below Normal

Dry Year

Annual Rainfall

2713.4

mm.

2219.5mm.

1854.8mm.

1493.5mm.

1304.3mm.

962.5mm.

No.of Rainy Days

84 97 95 77 65 70

Tier-A2.5-25 mm.

54(65%)

53(54%)

76(80%)

55(72%)

47(72%)

61(87%)

Tier-B25-55 mm.

15(18%)

40(42%)

18(19%)

18(23%)

13(20%)

8(11%)

Tier-C55-115 mm

11(13%)

3(3%)

1(1%)

3(4%)

5(8%)

1(2%)

Tier-D115 above

4(4%)

1(1%)

0(0%)

1(1%)

0(0%)

0(0%)


Reliability of Rainwater tank for water substitution


Impervious control in residential zones of Medinipur


OBJECTIVE Storm water management

Suggested Tools and Techniques


Water Sensitive Road Design

Conventional versus water sensitive road cross section

Verge design and management


Planning Tools for WSUD

Streetscape layouts


Networked public open space incorporated in development

Integration of housing with waterway corridor

Conventional versus water sensitive road layout

Neighbourhood Design


Sustainable options in Water Sensitive city

OBJECTIVE Facilitating Change

• Waste as a Resource, using waste water as fertilizer

• Demonstrate success by conducting tour to show case program giving benefits to society

• Undertake a water Challenge by comparing water bills regularly and seeing the savings

• Fewer standards, more rule of thumb to focus on outcomes


Ideas for adoption

OBJECTIVE Capacity Building

• Import Water Knowledge by setting up a centre, to help mitigating disaster management.

• Develop and maintain informal networks with like minded people for inspiring new ideas.

• Create a Water Charter to set the agenda for all future decision.

• Capacity building programs that train the trainer in creating water management expertise


Ideas for adoption

• Create a water mascot to capture public attention and support

• Open water treatment sites to the public to help understanding the actual treatment process

• Include social scientists and psychologists in projects for multi-disciplinary involvement.

• Improving community water literacy by targeting water education and marketing program

OBJECTIVE Community Engagement


Future Planning

Water planning beginswith land use planning


Who would adopt these ideas

• District Authority - for mandatory task of addressing the matters;

• Govt. Departments - for supplying all type of water related information;

• Volunteers - to assist in stuffing envelopes to collecting water samples;

• Business Owners - to readily sponsor publicity events;• Private Land Owners - for permitting implementation of best

management practice;• Teachers - to add a separate section on water

sensitivity in curriculum; • Private Individuals - to make cash and kind contribution

Variety of stakeholders


Developments to which WSUD applies

New residential villas, flats and townhouses greater than 1,000 m2 total site area.

All land subdivisions that results in 3 or more allotments and / or are greater than 2,000 m2 total site area, whichever is less.

All new commercial, retail, mixed use and industrial development greater than 1,500 m2 total site area.

All alterations and additions to existing commercial, retail, mixed use and industrial development with a total site area greater than 2,000 m2, which results in increase in building footprint or gross floor area of greater than 50%. WSUD is to be applied to the whole site.

Any development which involves the construction or designation of 10 or more additional car parking spaces, whether the spaces be covered or uncovered.


How to get WSUD to happen

Establishment of a wider network of automated weather stations andautomated rain gauge stations;

GIS mapping of catchments and surveying and assessing land usepatterns with emphasis on drainage, vegetation cover, silting,encroachment, flood prone zone, human activities and its impact oncatchments and water bodies;

Developing an inventory of water bodies and wetlands especially thosewith unique features;

Systems to track leakages in piped networks;

Identify new technologies for wastewater recycling-includingmembranes and filters;


Innovate local or on-site sewerage systems and technologies;

Mandating Rainwater harvesting and artificial recharge in relevanturban areas;

Develop models of urban storm water flows and estimating drainagecapacities for storm water;

Introducing small piped network for urban fringes and densely settledrural areas;

Set up Laboratories with simple water quality testing kits.



Inter-disciplinary planning and design process



Concluding Remarks

Developing a water sensitive city is a great challenge.

1. Collaboration and networking are essential.

2. It was proved that the local community be involved in all kind ofdevelopment, because our ideas needed initially to be seen within theexisting development framework.

3. A common philosophical base on how to integrate land and waterplanning and management in the urban context to achieve a multi-objective output in terms of an ecologically sustainable urbanenvironment, must be established.

4. There is a need for development of adequate information basesand evaluation techniques.

5. Adopting an education and public information flow in both directions.


Future Scope of Research

Reuse potential of urban storm water.

Design strategies for sullage and waste water network specially

to avoid contamination.

Urban drainage system under sustainable city concept.

Decision support matrix for roof top rain water management.

Economic and environmental benefits of source control

strategies in urban water cycle management.

Role of Water Sensitive Urban Design in Urban Water ...cdn.cseindia.org/userfiles/Somnath Sen.pdfDr....

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