Water SensitiveUrban Design

WATER FACTSHEET:

Can Weather Cause War ? Can Water Cause War ?

Saat ini sekitar 1.1 milyar penduduk dunia tidak memiliki akses air bersih, dan sebagian besar didominasi oleh wanita dan anak-anak (UNDP)

1 dari 5 orang di negara berkembang hidup dengan air kurang dari 20 liter per hari, sedangkan penduduk negara maju hidup dengan air 200-300 liter/hari. Bahkan penduduk Amerika lebih boros lagi 575liter/hari (UNDP)

Penduduk negara berkembang, seperti Indonesia, Philipina dan banyak negara di Amerika Selatan membayar air 5-10 kali LEBIH MAHAL dibandingkan penduduk negara kaya.

9. Banyak sungai besar di dunia, dalam jangka waktu 20 tahun akan surut, saking parahnya malah tidak akan bermuara lagi di laut. Termasuk diantaranya adalah Sungai Mekong, Sungai Kuning dan Sungai Colorado.

• Drain/fill land to allow development – pipe everything - ends up in rivers and ocean

• Construct trapezoidal drains (modify waterways) leading to sumps

• Separate systems for water supply, wastewater and stormwater

• Use potable water for everything

• Water issue – left too late in the planning process, for example: Puri Indah, Taman Palem

TRADITIONAL APPROACH IN WATER ENGINEERING DESIGN

WHAT IS WATER SENSITIVE URBAN DESIGN ?

Water Sensitive Urban Design (WSUD) is a philosophical approach to

urban planning and design that aims to minimize hydrological and water quality

impacts of urban development.

STORMWATER MANAGEMENT

sustainable urban water management.

“WATER SENSITIVE”– Sustainable solutions for managing water resources –

technical and nontechnical (governance)– Protecting aquatic ecosystems

“URBAN DESIGN”– Integrating total urban water cycle management into the

urban design andbuilt form – landscape architecture, building architecture

– Enhancing the landscape/recreation/habitat– Creating an “Urban Ecology”

Protect natural systems

protect and enhance natural water systems within urban developments. Promoting and protecting natural waterways as assets allows them to function more effectively and supports the ecosystems that rely on them.

Integrate stormwater treatment into the landscape

use stormwater in the landscape by incorporating multiple use corridors that maximise the visual and recreational amenity of developments. The natural stormwater drainage system can be utilised for its aesthetic qualities within parklands and walking paths, making use of natural topography such as creek lines and ponding areas.

PURPOSE

Protect water quality – improve the quality of water draining from urban developments into receiving environment. Through filtration and retention, water draining from urban developments can be treated to remove pollutants close to their source. This approach reduces the effect that polluted water can have upon the environment and protects the natural waterways.

Reduce runoff and peak flows – reduce peak flows from urban development by local detention measures and minimising impervious areas. Local detention and retention enables effective land use for flood mitigation by utilising numerous storage points in contrast to the current practice of utilisation of large retarding basins. This approach subsequently reduces the infrastructure required downstream to effectively drain urban developments during rainfall events.

Add value while minimising development costs – minimise the drainage infrastructure cost of the development. The reduction of downstream drainage infrastructure due to reduced peak flows and runoff minimises the development costs for drainage, whilst enhancing natural features such as rivers and lakes that add value to the properties of the area.

PURPOSE

A Water Sensitive City• Flexibility & Adaptability“Cities as water supply catchments”

– Diversity of water sources of water (ie. alternative sources including stormwater, sewer mining, recycled wastewater, desalinated water)

– Diversity of infrastructure (ie. centralised and decentralised systems promoting a fit-for-purpose framework for matching water usage to water quality)

“Like a share portfolio, flexible and cost effective access to the diverse water sources will be underpinned by a diversity of centralised and decentralised water infrastructure”

Summary of Singapore’s water supply strategy

[The four National Taps of Singapore]

1.NEWater – 4 high-grade reclaimed water factories – supplying 30% of Singapore’s waterdemand).

2. Desalination Plant – (10% of Singapore’s water demand) desalination plant commissioned in 2006.

3. Urban Stormwater harvesting – marina barrage – Singapore’s 15th reservoir– supplying approximately 30 mgd (10% of Singapore’s water demand); localcatchment supplies approximately 150 mgd or 680 ML/d

4. Water from Malaysia – traditionally supplies approximately 50% of Singapore’s water demand• Demand management – including “pricing water to reflect its scarcity”

Creating a Reservoir in the City

which will act as a tidal barrier to control flooding in low-lying areas in the city, create a new reservoir to augment Singapore's water supply and serve as a major lifestyle attraction in Singapore's downtown

A Water Sensitive City

• Flexibility & Adaptability“Cities as water supply catchments”

• Improved water quality and ecosystem health of urban aquatic environment

Amount of stormwater run-off Intensity of Development

Increased overland flow Increased natural pollutants

Stormwater drains City’s waterways

Site to “hold and use the rain where it falls”Objectives:

To integrate stormwater detention with the provision of open space and the urban landscapeTo minimize the effect of stormwater pollution on receiving waters, encourage water conservation and reduce stormwater runoff to minimize floodingTo encourage the re-use of rain and grey water

BASIC STORMWATER MANAGEMENT

STORMWATER MANAGEMENT=

BIORENTENTION

An engineered process to manage stormwater runoff, using the chemical, biologicaland physical properties afforded by a natural, terrestrial-based community of plants, microbes and soil.

Bioretention provides two important functions: (i) water quantity (flood) controls; and (ii) improve water quality through removal of pollutants and nutrients associated with runoff.

Developed by. Prince George’s County, Maryland (1990)

Early concepts

Ultra Urban AreasUltra urban areas are densely developed urban areas in which little pervious surface exists. Bioretention facilities are ideally suited to many ultra urban areas, such as parking lots. While they consume a fairly large amount of space (approximately 5% of the area that drains to them), they can fit into existing parking lot islands or other landscaped areas.

Stormwater HotspotsStormwater hotspots are areas where land use or activities generate highly contaminated runoff, with concentrations of pollutants in excess of those typically found in stormwater. A typical example is a gas station or convenience store parking lot. Bioretention areas can be used to treat stormwater hotspots as long as an impermeable liner is used at the bottom of the filter bed.

Stormwater RetrofitA stormwater retrofit is a stormwater management practice (usually structural) put into place after development has occurred, to improve water quality, protect downstream channels, reduce flooding, or meet other objectives.Bioretention can be used as a stormwater retrofit, by modifying existing landscaped areas, or if a parking lot is being resurfaced. In highly urban watersheds, they are one of the few retrofit options that can be employed.

However, it is very expensive to retrofit an entire watershed using bioretention areas since they treat small sites.

Where ???

Improve Stormwater Quality

to control sediment discharge

To remove coarse to medium sized sediments

SEDIMENT BASIN

TRADITIONAL SEDIMENTATION BASIN – CONCEPT LAYOUT

SEDIMENTATION BASIN – KEY ELEMENTS

A Water Sensitive City• Flexibility & Adaptability“Cities as water supply catchments”

• Improved water quality and ecosystem health of urban aquatic environment

• Building social capital (ie. community receptivity, professional capacity, institutional capacity)

HONGKONG WETLAND PARK

Major functions of wetlands are:

Store Wetlands absorb massive run-off and release water slowly, e.g. floodplain

Filter Wetlands can trap waste and break down pollutants, e.g. reed beds

Protect Wetlands protect our shore lines against storm waves, floods and erosions, e.g. mangroves

Provide Wetlands provide us food, medicines and natural materials, e.g. rice paddies

Shelter Wetlands are home to living organisms and support complex food web, e.g. coral reefs

VICTORIA PARK

The removal of storm water

Contaminated downstream-Alexandra canal

Carriageway towards to the center of east-west streets

Porous pipes

A system of weirs and inlets

Central parkA detention pond is a low lying area that is designed to temporarily hold a set amount of water while slowly draining to another location.

They are more or less around for flood control when large amounts of rain could cause flash flooding if not dealt with properly.

Sedimentation pond

Circulation and Access

• Networks• Vehicular• Pedestrian• Public Transport• Cycle• Landscape elements

Networks

Vehicular

Pedestrian

Public Transport

Cycle

Landscape elements

Stormwater drainage system - Performance criteria:

• ‘Fit’ as much as possible, within the hydrology of the natural system• Emphasize stormwater detention, vegetated overflow lines, sensitive

location of discharge points and quality of receiving waters• Minimize non-porous surfaces to reduce stormwater run-off• Store water for re-use• Retain existing trees• Excludes land needed for natural or modified drainage, floodplains,

remnant vegetation, environmental values• Stormwater drains designed to accept rainwater only excluding other

pollutants from the City’s waterways

Stormwater management by Development - Performance criteria:

• Minimize changes to the natural hydrology of the local area or region• Achieves water conservation• Protects water quality• Produces cost-effective development• Enhances local recreational opportunities by maximizing the dual use

of drainage system

Environmental Vs DevelopmentalSelf-reinforcing Strategies?

EnvironmentalEnvironmental DevelopmentalDevelopmental

11 Introducing sustainable water managementIntroducing sustainable water management Victoria Park as a model for development and Victoria Park as a model for development and transformation of Green Squaretransformation of Green Square

22 Integration of Stormwater Management with Integration of Stormwater Management with open spaceopen space

Broader network of public open space within Green Broader network of public open space within Green SquareSquare

33 Environmental infrastructure across the siteEnvironmental infrastructure across the site Circulation and movement across the siteCirculation and movement across the site

44 Bioretention Swale SystemBioretention Swale System StreetscapeStreetscape

Flexibility for future changeFlexibility for future change

55 Infrastructural support – Gross pollutant trapsInfrastructural support – Gross pollutant traps Supporting a highly urbanized landscapeSupporting a highly urbanized landscape

66 Water DetentionWater Detention Central ParkCentral Park

Public Domain for the communityPublic Domain for the community

77 ““Storm Waters” installationStorm Waters” installation Public ArtPublic Art

88 Sedimentation pondSedimentation pond IrrigationIrrigation

BiodiversityBiodiversity

RAIN GARDEN – FEDERATION SQUARE

RAIN WATER TANKS – RYDER OVAL PAVILION