Sustainable development through River Restoration

Techniques of Sustainable Development

Submitted by-

Shraddha Bahirat2012MUD005

Before

After

River Restoration

Introduction

One of the most pre-dominant factors for selection of site for establishing permanent settlements since ages

It has been a source of

Water

Food

Transport

To dispose wasteHydropower

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• It has acted as major part ofpeople’s social and cultural life,thus making it an integral part oftheir lifestyle.

• And habitat sustaining greencorridors in the city, thusmaintaining the ecology andtemperatures around it.

• However the river channels havebeen harnessed and modified tosuit the requirements of thegrowing settlements.

• Rivers have been straightened andculverted to provide floodprotection and to make maximumuse of land for housing, industryand agricultural use.

“Disturbed the ecological balance and disrupted the riverine systems and their functions ”

Aim and Objective

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Aim:

The study endeavours to analyse through case studies and examples of riverrestoration the impact of restoration on the social, economic and ecologicallife and development of the city.

Objectives:

• To understand the ecology and basic concepts related to the river• To study the need for river restoration• To examine the types and techniques of river restoration• To understand the relation between sustainability and river restoration

Understanding Rivers, Water shed and

stream orders

• A watershed is the land area drained bya particular stream or river.

• Small streams join to form largerstreams in a branching pattern thatforms a drainage network.

• Therefore, larger watersheds are madeup of a joining of smaller watersheds.

• The different channels draining thesewatersheds can be designated by howmany tributaries they have or by order.

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A cross section of a river corridor

• First order stream channel has no tributaries, whentwo first order streams join; they create a second-order stream.

• When two second order streams join they create athird order stream and so on.

• One can designate a stream by its order to get theconcept of the size of the drainage area concerned.

• Stream drainages follow the lowest topography andform valleys and become separated from eachother by ridges or divides.

Two types of floodplains:

• Hydrologic floodplain, the land adjacent to the baseflow channel residing below bankfull elevation. It is inundated about two years out of three. Not every stream corridor has a hydrologic floodplain.

• Topographic floodplain, the land adjacent to the channel including the hydrologic floodplain and other lands up to an elevation based on the elevation reached by a flood peak of a given frequency (for example, the 100-year floodplain).

• 100- year and 500-year floodplains are commonly used in the development of planning and regulation standards.

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The need for River Restoration

• Urbanisation has affected The physical process of river growth Modified stream structure Influenced the function of the river systems

• More than 60% of the rivers in the world haveexperienced high level of human modification

• Urbanization causes river degradation due to theamount of impervious surface area which causes Increased erosion, Channel destabilization and Widening of stream

• Leading to loss of Habitat from channelizationExcessive sedimentation Increases in temperature andReduction in large woody debris causing more

homogeneous in stream habitats.

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• Urbanization of watersheds isalmost invariably accompanied byloss and alteration of aquatichabitats, two of the mostfrequently mentioned causes forlosses of aquatic biota.

• Rapid urbanisation has resulted ina clear decline of drainagedensity and an obvious ecologicaldegradation in river ecosystem.

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• Geographically, there is a shifting of urban land, and the extent ofdrainage density decreases from the core of towns to the outskirts.

• Outward expansion of the urban land and the decrease/disappearance of the wetland and water bodies are found to beamong the most important driving forces explaining the ecologicaldegradation in river ecosystems.

• The impact of urbanisation on the water body/ river can be studiedunder four categories: Hydrology Geomorphology Water Quality Habitat

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Hydrology• The impact of urbanisation on hydrology is evident from the following facts:

1. Disruption of natural water balance2. Increased flood peaks3. Increased stromwater runoff4. More frequent flooding5. Increased bankfull flows6. Lower dry weather flow

• The bankfull flooding (or the condition of the flow that fills up the channel) occurs much morefrequently in highly urbanized areas and has the potential to be extremely erosive anddamaging to the natural morphology of the stream.

The Stream and its floodplain before and after development

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Geomorphology

• The impact of urbanisation on geomorphology of the river is as follows:1. Stream widening & erosion2. Reduced fish passage3. Degradation of habitat structure4. Decreased channel stability5. Loss of pool-riffle structure6. Fragmentation of riparian tree canopy7. Decreased substrate quality

• In watershed with less than 5% impervious coverstream are:1. Stable and persitine,2. Maintaining good pool and riffle structure3. A large wetted perimeter during low flow with

a good riparian canopy coverage.

• 8- 10 % impervious cover the stream is:1. Relatively stable however erosion are more

apparent and include loss of the wettedperimeter

2. More eroded material in the bank and debris.

• 10% impervious cover the stream is:• Tree roots are exposed and the pool riffle

structure seen in sensitive streams is lost.• 20% impervious cover with decreased

substrate quality due to more materialflushing through the system. Active erosionbecomes much more evident

• The stream having a surrounding area ofapproximately 30% impervious cover. Thelarge amount of impervious cover increasesthe size of the stream by a factor of five toten.

• In many highly urbanised areas, naturalstreams have been channelized to speedrunoff along, but these fail to provide anyhabitat value.

Impervious Cover and Surface runoff relationship

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Water Quality• The impact of urbanisation on the stream

water quality is evident through the following:1. Increased stream temperature2. Increased pollutants3. Increased risk of shellfish bed/ beach clouser

• Once urban development moved into thefloodplain, rivers were heavily modified toallow maximum land take and to providethe subsequent flood protection that thesenew developments required.

• Hence there is a urgent need to check thesituation for the overall sustainabledevelopment of city.

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What is Restoration? Types of restoration

• River restoration describes a set of activities that help improve the environmental health ofa river or stream.

• On a larger scale, a restoration project might include the entire floodplain, removing paststructures and restoring more natural processes and channel forms to the watercourse.

• On a smaller scale, restoration might be simply removing the hard banks and replacingthese with more natural features.

• Even using systems such as green roofs can contribute to restoration by enhancingsustainable drainage and biodiversity.

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Relation between river restoration and sustainable development

The major benefits of river restoration can beclassified under three major heads:• Environmental benefits• Social benefits• Economic benefits

Environmental Social

Economic Environmental benefits

Restoring the river’s original form allows the naturalprocesses of erosion and deposition which cansustain a rich variety of aquatic life.• Improving the river corridor• Improving flood storage capacity• Addressing water quality by:

1. Promoting sustainable urban drainage systems innew developments.

2. Creating green river corridors and buffer zonesthrough urban centres.

3. Promoting less-intensive agricultural practices.4. Prosecuting polluters.5. Improving sewage treatment works.

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Social benefits1.Re-establishing natural channel processes2.Improving wellbeing3.Balancing community access and the needs of wildlife4.Providing sustainable transport5.Educating the community

Economic benefits1.Generating sustainable development and attracting business

Thus the major benefits of river restoration in Urban areas includes:1.Improved quality of housing and landscape2.Improved sustainable transport - footpaths and cycleway, jogging tracks3.Climate change adaptation and reduction in flood risk4.Improving the river corridor and green space networks5.Improving biodiversity6.Addressing water quality and land drainage

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Case Study: 1

Cheonggyecheon Restoration, Seoul, South Korea

• Flows through the heart of the city passing through the CBD and connectsthe Han river in south

• Cuts the city in two distinct parts

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Early 20th Century

The stream was an integral part of the life of the citizens

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• Development of Slums• City faced problems of sanitation• The stream started getting polluted

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• The solution was to cover the stream in1958-77

• Further with rapid urbanization andneed for transportation Cheonggyecheonhighway was constructed on the stream .

• Followed by construction of flyovers inthe area over the stream in 1999.

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• Building: over 6,000• over 100,000 small shops• Nation’s biggest commercial area• CBD redevelopment stopped where the• Cheonggye Expressway started• Population and employment reduced Population:

40,000Employment: 80,000 in 10 years• Business headquarters moved to Gangnam (new

sub-center)• Industries in CBD lost competitiveness• Maintenance of the highway and flyover

increased

By 2002

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• Restoration Project was announced on 1st

July 2001• Total length: 5.84 km• Restoration of upper reaches of CGC on a

long term basis• Divided into 3 sections to reduce the

construction schedule• Covered structure and highway: 5.4 km• Waste (concrete+asphalt): 872,400ton

(96% recycled)

The Restoration Process

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Design Criteria

• Secure the stream capacity for 200 years frequency rainfall (118mm/hr)• Access to Water: Install sidewalks along the lower level of the bank• Basic design: secure flood capacity for 200 years frequency rainfall and

introduce lower terrace to enhance easy access to water

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Sewer System

• Combined sewer system for rainfall and wastewater• Capacity : 3 times of estimated wastewater

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Concepts• New green belt with waterfront: West to East• Gradual transformation from urban landscape to natural environment• Create ecological biotop and environment• Thematic places: waterfall and fountains

Challenges

Cheonggye road & highway• Urban backbone corridor• 170,000 vehicles/day• Traffic disaster warned• Media, interest group• Traffic simulation• Project delay

• Transportation• Neighboring Merchants

Challenge 1: Transportation

• Discourage driving cars in the city centre: Leave cars at home one out of 10 days

• Improve traffic flow systemOne-way streets

• Improve public transport: Bus-only lanesDowntown shuttle buses

Solution for transportation

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• Stimulate business activityReduce parking feeImprove parking system for loading & unloadingPromote Cheong Gye Cheon stores

• Financial support and subsidiesLow-interest loansGrants for the market remodeling

• Special arrangement for street vendors

Solutions to merchants

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• Business declineAccess difficulty: traffic congestionWorse environment: noise & dust due to construction

Challenge 2: Neighboring Merchants

Restoration Progress and Process

Stage 1: Scaffolding (July 2003)

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Stage 2: Highway Demolition (Aug 2003)

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Stage 3: Covered Road demolition (Jan 2004)

Stage 4: Sewer, road and bridge construction (Sep 2004)

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Stage 5: Landscaping of the recovered area (May2005)

Final Finishes and opening on Oct 2005

May2005 to 1 Oct 2005

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Monitor the changes due to the project from Jan 2003~May 2006 (before, during andafter the project)Monitoring areas• Land use• Industry• Environment• Ecology• Traffic• Public opinion• Ripple effect

• Speed in CBD15.5 to 3.6 km/hr (-12.3%)– Morning peak: 17 km/hr– Evening peak: 12 km/hr

• Car in/out flow1.56M to 1.27M (-18.6%)

• Public transport rider-shipBus: + 6~10 %Subway: + 6~9 %

Monitoring

Traffic

• Air: NO₂: 69.7 to 46.0 ppb (-34%)

• Water quality: BOD: 100~250 to 1~2 ppm

• Noise level reduced• Heat island effect relieved• Wind corrider created

Environment

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Thermal Image 27 July, 2005

Reduction of 3 degrees in temperature

Public Survey by government for environmental improvement

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Changes in Ecology

6 to 25 species

6 to 36 species

15 to 125 species

Insects

Birds

Fishes

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Enhanced Public life

Case Study: 2

Osho Ecological Park- Osho Teerth, Pune

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• Famously called the nala park• An example of how wastelands

could be aestheticallytransformed into parks andcould prove a boon for our townand cities.

• Tastefully laid out Japanese-stylegarden

• The site was a piece of barren land.• A nala ran through it carrying black sludge.• Used oils was also being disposed into it by the nearby railway yard.• Human waste from a nearby slum also flowed into it.• Putrid wastes emitted foul smell.

The need to restore and revitalize

The process of restoration

• The Ashram management took it over in 1989 torevitalise the area.

• The nala flowed from north to south, discharging 500gallons of water a minute at a particular point.

• First a barricade was raised to keep off the cattle.

• It was then meshed off with iron grills to catch thefloating solid garbage once it entered the proposedpark.

• The stream was then made to course like a serpentover the land to allow maximum oxygenation of water.

• It was planted with water hyacinth and stocked withfish such as gambusia and silver carp which eatpollutants and mosquito larvae.

• It was then passed through a sand filter.

• The oxygenation and filtering made the water almost90 per cent pure, perfectly okay for irrigation and fishculture.

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• Local contractors were invited to dump their debris tocreate hills and dales.

• Trees and shrubs that already existed on the site werepruned.

• Helped by Pune’s climate, the foliage blossomed intoa thick vegetative cover.

• With fine hedges and pools and fountains, the OshoPark serves as an inspiration for creating anenvironmental project.

• The key element in the planning was slowing downthe water stream in order to allow the naturalcleaning process to be re-established.

• The polluted water was purified naturally, usingholding ponds with selected plants and stone.

• The purified water is distributed throughout thegarden with underground irrigation.

• The sparkling stream flows throughout the length ofthe ashram.

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The revitalisation of the stream and creation of the park has greatly improvedthe ecology and the quality of life of the surrounding areas.

Sabarmati River Front Development

Case Study: 3

Ahmedabad was established on Sabarmati in 1411

Sabarmati has been an important river for Ahmedabad:• As a source for drinking water• As a place for recreation• As a place for the poor to build their hutments• Place for washing and drying clothes• A place for holding the traditional ‘Sunday Market’• A place for farming

Traditional Sunday Market and as space for recreation For Framing

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For daily activities

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Growth of Ahmedabad along Sabarmati

Source: Sabarmati Riverfront Development, Integrated Environmental Improvement and Urban Revitalization, India Urban Conference, Mysore, November 2011

The city initially grew along the eastern coast of the river and the development gradually spread across the river on the western side with the river playing a major part in the development of the city

• Encroachments reduced the river’s flood carrying capacity

• Sewage from the slums flowed directly into the river• A few nalas brought sewage into the river

Storm water drains spewed untreated sewage into the riverIt became a place to dump garbage

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Haphazard and dull development came up along the riverfront

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• The city turned its back to the river

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• The river becameinsignificant in the lifeof the city

The river became inaccessible to the public

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• In order to reconnect the city with theriver the first known proposal fordeveloping the riverfront was given in1961 by prominent Ahmedabad citizensand the French architect Bernard Kohn.

• A 9 km stretch of the riverfront extendingfrom Subhash bridge to Vasna barragewas identified and it was proposed toreclaim 162 hectares (400 acres) of theriverbed.

• The Ahmedabad Municipal Corporation(AMC) set up the Sabarmati RiverfrontDevelopment Corporation Ltd (SRFDCL) inMay 1997.

• SRFDCL planned to sell or lease out a partof it to finance the project. In 2003, itextended the project to cover a 20 kmstretch from the Narmada main canal toVasna barrage.

Main features are the following:

• The reduction of the riverbedfrom a variable width of 600-300m to a fix width of 275 m, thusreclaiming 185 ha of land.

• The construction of RCCdiaphragm walls (10-20 m depth)and anchor slabs (10 m) toprevent the riverbanks fromerosion. After the finishing theanchor slab is turned in the so-called lower promenade.

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Reduction of river bed

Diaphragm wall and anchor slab

• The construction of RCC retaining walls(2.5 - 9 m) to protect the city fromflooding. The height of the walls isdetermined by the 100-year flood level.An upper promenade is created on topof the retaining walls.

• The dredging of the river bed in orderto provide soil for the filling of the spacebehind the RCC retaining walls. At least67.500 cubic meters are required for thefilling.

River RestorationConstruction of retaining wall

• The construction of interceptorsewers on both the riverbanksable to prevent the waste waterto flow directly into the river anddiverting it to the two sewagetreatment plants of Vasna andPirana.

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• The relocation of slum dwellers and theprovision of better living conditions to them.The first proposal was to relocate them inthree sites along the riverbanks, but the planhas changed afterwards and the relocationsites are now far from the river.

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The entire length of Sabarmati is returned back to public

Renewed the surrounding areas

The use of the reclaimed land for private residential and commercialdevelopments with a view on water to be sold to finance the project(the percentage has decreased from 20 to 15% because of the highincrease of the land value), two major roads, one on each riverbank(30%), gardens (26%), promenades (6%), informal market (3,6%) andthe rest for other public facilities

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Stitched east and west Ahmedabad

Facilitated the improvement ofthe surrounding residentialneighborhoods

Potential for new formal and informal commercial development

Potential for organizing trade fairs etc. Created a mile of cultural institutes, museums and hospital facilities

Potential for new recreational spaces like parks, promenade, open air theaters etc.

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Restoration of Sabarmati river and by developing itsriver front, the thus project achieves the following goalswhich it aimed at the conception of the riverfrontdevelopment idea:

• Elimination of the danger of floods in the currentcontext of climate change.

• Establishment of better hygienic conditions through anew sewerage system.

• Increase the ground water recharge through thestorage of water within the river bed.

• Improvement of the living conditions of the slumdwellers.

• Renewal of the surrounding areas to cater the futuredevelopment of the city.

The case of the Sabarmati river shows therefore the “politics of scale” (Smith, 1984)around which a large debate has risen in the last two decades. Questioning one of the coreissues of the Sabarmati River Front Development Project - the origin of water - a wholerange of new issues come into the picture.

Criticism for the project

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Conclusion

River restoration takes into consideration all the aspects of sustainability like• Ecology and Environment• Economy,• Social life of the citizens,• History and culture of the city• Addresses the growth trends and urbanization

• The river restoration in any city not only improves the quality of river and its ecology but also affectsthe other sphere of sustainability i.e social and economic life of the city and its citizens.

• Helps to return the valuable land for public use, recreation and general activities of the citizens;

• It creates opportunities to give respect to the heritage and ecology of the city as it considerablyimprove the air quality, water quality and the surrounding environment

• It helps to orient development of the city in integration with river.

• It regenerates and renews all the precinct around it as it enhance the quality of life , provides economicboost to the surrounding areas , gives an impetus to improve the general economy of the city in largercontext and saves the ecology by curbing the further deterioration of the river.

Hence river restoration and appropriate measure to revitalize the surroundings in the citieshaving degenerated streams can assist to enhance sustainable development of the city.

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Reference:

• (n.d.). Retrieved September Fourth, 2013, fromhttp://sustainabilitywriter.wordpress.com/2012/07/04/the-cheonggyecheon-river-restoration-project-seoul-south-korea/

• Association, D. o. (March, 2004). Ecological River Front Design. Wasington DC: AmericanPlanning Association.

• centre, T. r. (January, 2009). London Rivers Action Plan. London.• Habitat, U. (n.d.). Urban patterns for a green economy, working with nature. Kenya: UN

Habitat.• J. L. Cassin & L. Tear, R. F. (n.d.). Sustainable river restoration in urban streams - using

biological indicators to establish environmental flow targets in the Pacific Northwest.• Khorshed Alam, D. M. (2006). Sustainibility and river restoration. 35 th AustralianConference of economist (ACE), (pp. 1-21). Perth.

• Paukert, J. L. (2009). Urbanization in great plains river: Effects on fishes and food webs.Wiley inter science, 1-12.

• Redondo, M. D. (2003). Social Impact assesment for river restoration: A more sustainableperspective. Thesis.

• Yuan Wen, P. J. (2006). Impact of urbanisation on structure and function of river system-Case Study of Shanghai,China. Chinese Geographical Science.

• http://link.springer.com/content/pdf/10.1007/s11769-006-0002-9.pdf• http://onlinelibrary.wiley.com/doi/10.1111/1467-9493.00117/abstract

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