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CARRYING CAPACITY

/9/2011

1 DR. RAJIB BHATTACHARJYA

EASTER ISLAND

• Located 3500

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kilometers off the coast of Chile

• It is the world’s

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It is the world s remotest inhabited island.

M t d d• Most advanced society with great cultural heritage.

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Easter Island Statue, built around 700 AD

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EAS IS AEASTER ISLANDDiscovered by Polynesians ~ A.D. 1000

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Population grew to several thousandsUsed trees for canoes to hunt dolphins

d d f ki

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Used wood for cookingAlso ate birds, eggs, vegetables

Resources (trees) depletedResources (trees) depletedNo canoes, no dolphinsWarfare over land, food resources

Population fell to 100 when visited by a Dutch in 1722.

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BASICS ABOUT POPULATION GROWTH 2/9/20

The environment has a carrying capacity for every organism based on the available resources

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organism based on the available resources

If resources are abundant and readily available then a If resources are abundant and readily available, then a population will show exponential growth

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During exponential growth the increase in During exponential growth the increase in population size varies with the number of individuals presentIncrease is gradual at first, but rises sharply Increase is gradual at first, but rises sharply as more individuals become part of the populationUnlimited resources allow everyone to U e eso ces a ow eve yo e o reproduce! 6

ENVIRONMENTAL RESISTANCEFFACTORS

Populations will continue to grow exponentially

2/9/20p g p yuntil they come up against limiting factors or resistance factors

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Resource limitationsFood, nutrients, water, sunlightSh l Shelter, space

Competition from other speciesp pPredationWaste accumulation

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LOGISTIC GROWTH2/9/20011

In the real world resources are often limitingThe first part of the growth resembles

ti l thexponential growthBut over time, the population size levels off in logistic growth at a point called the carrying g g p y gcapacity 8

CARRYINGCARRYINGCAPACITY 2/9/20

The carrying capacityof the environment

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represents the maximum number of individuals of a particular species that an area can support indefinitely support indefinitely without degrading

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CARRYINGCARRYINGCAPACITY 2/9/20011

Natural populations seldom approach carrying capacity smoothlycapac ty s oot yOr stay at the carrying capacity once reachedThey usually fluctuate around the carrying

itcapacityOvershooting it or falling below depending on resources

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ENVIRONMENTAL CARRYING CAPACITY

A population gradually increase to the maximum size that available resources will support—the environment’s carrying capacity

2/9/20environment s carrying capacity.Thereafter, the population fluctuates around this size with good and bad cycles—e.g. rainfall.

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g y g

12000

Carrying Capacity = 10,000• What happens if

6000

8000

10000

atio

n si

ze

happens if something drastically reduces this

2000

4000Popu

lareduces this population?

What could 00 100 200 300 400 500 600 700 800 900 1000

Time (years)

• What could do that??

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RECOVERY VS. REDUCED CAPACITY

If the population is reduced because of a 1-time catastrophe—e g a

Recovery to Carrying Capacity = 10,000

10000

12000

time catastrophe—e.g a long drought—then over time it will recover b k i f i

4000

6000

8000

Pop

ulat

ion

size

back to its former size.But if the overall environment is

0

2000

0 100 200 300 400 500 600 700 800 900 1000

Time (years)

environment is reduced—e.g. half the forest is cut down—

Carrying Capacity reduced to 5,000

10000

12000

then the population adjusts to a new, lower carrying capacity

4000

6000

8000

Pop

ulat

ion

size

carrying capacity.0

2000

0 100 200 300 400 500 600 700 800 900 1000

Time (years)

CARRYING CAPACITY

So human population recovered after the Black

2/9/20recovered after the Black Death—in fact the global human population has not

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p pyet reached carrying capacity.S l fi h l ti Salmon fish population increases, then had their habitat reduced by dams yand pollution. The population had to adjust to a much lower carrying a much lower carrying capacity.

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What is The Limit

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U C C CURBAN CARRYING CAPACITY CONCEPT

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Carrying capacity can be defined as the number of individuals that

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can be supported in a given area without degrading the natural, social, cultural and economical environment of the area for the present and future generation.

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SUSTAINABILITYSUSTAINABILITYResource harvest sustainability refers

2/9/20yto the quantity of the resource that is harvestable indefinitely.Ecosystem sustainability refers to

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Ecosystem sustainability refers to maintaining an ecosystem’s essential functions and properties while harvesting an ecosystem resourcean ecosystem resource.Sustainable economy maintains its level of activity over time.Sustainable development requires the integration of economic and social growth and environmental protection.and environmental protection.

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FACTORS EFFECTING URBAN CARRYINGC PCAPACITY

Environmental and ecological

U b f iliti

g

CarryingUrban facilities InstitutionalCarrying Capacity

Public perceptionp p

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ENVIRONMENTAL CARRYINGCAPACITY

Determining factors for

2/9/20Determining factors for environmental carrying capacity f b il l

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of an urban area are soil, slope, vegetation, wetlands, scenic resources, natural hazards, air and water quality, and energy q y, gyavailability, etc.

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URBAN FACILITY CARRYINGCAPACITY

Housing water supply sewage

2/9/20Housing, water supply, sewage, waste treatment, road network,

il t k h lth

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railway networks, health care, educational facilities, employment facilities, etc. are some of the factors that measure the carrying capacity of urban area area.

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PUBLIC PERPETUAL CARRYINGCAPACITY

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The level of public awareness which

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The level of public awareness, which generally includes human attitudes,

l b h i h bit tvalues, behavior, habits etc.

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INSTITUTIONAL CARRYINGCAPACITY

The institutional carrying capacity

2/9/20The institutional carrying capacity will be governed by the governmental structure financial

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governmental structure, financial stability, economy and cultural limits on environmental decision limits on environmental decision making, etc.

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FRAMEWORK FOR CARRYING CAPACITYCALCULATION FOR HILLY AREA

Step1: Delineation of hilly area From the Master Plan 2/9/20

Step2: Demarcation of non developable areas based on analysis of physical characteristics of the urban hilly area and provision of different statute

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and provision of different statute

Step3: Determination of area required for different infrastructure and facilities like drainage networkinfrastructure and facilities like drainage network provisions, water supply plants, sewerage and waste treatment plants. This area requirement for infrastructure will be a function of carrying capacity and will bewill be a function of carrying capacity and will be calculated iteratively

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FRAMEWORK FOR CARRYING CAPACITYCALCULATION FOR HILLY AREA

Step4: From the above calculation net area available for

2/9/20Step4: From the above calculation net area available for residential development will be calculated

Step5: Determination of floor area required for each

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Step5: Determination of floor area required for each person based on socio-economic status of the prospective residents of the developable hilly area, habit, daily water requirement and waste water generation,daily water requirement and waste water generation, amount of daily solid waste generated, market demands, cultural activities and climate in the area

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Step6: Based on above calculations carrying capacity of the study area may b l l t d t t d b lbe calculated as stated below:

CC = (AH – (ANDA + AIFCC) x FAR/S 2/9/20

Where, AH = Hilly area (as per step 1)ANDA = Non developable area (as per step 2)AIF= Area required for infrastructure and facilities (as per step 3)

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AIF Area required for infrastructure and facilities (as per step 3)FAR = Floor area ratio as prescribed in Master Plan, Building Bye-law

etc.S = Floor area per person (as per step -5)

Step7: Based on the population calculated in step 6 requirement of areas for different infrastructure facilities may be calculated using the set spacefor different infrastructure, facilities may be calculated using the set space norms and adequacy of institutional frame work may be checked. Thus, considering infrastructure, facilities and adequacy of institutional framework final carrying capacity may be decided with time

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GIS APPLICATION2/9/20011

Waterways

Natural Depression

Rocky land

High Slope Land

Total Watershed Area 25

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Total Developable area of the Watershed

Non developable area of the Watershed26

DETERMINATION OF CARRYING CAPACITYBASED ON HYDROLOGICAL CAPACITY OF THEWATERSHED

Determination of net density :

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persons)(inCapacityCarrying

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Area lResidentia Suitablepersons)(in Capacity Carrying

Check for adequacy of drainage system, sewerage system etc which were not explicitly sewerage system etc which were not explicitly considered during carrying capacity calculation

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EXAMPLE FOR DRAINAGE ADEQUACY

Waste water i

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generation from the proposed carrying

+Strom water generation from the

watershed

Check adequacy of drainage

system

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ca y g capacity

watershed

If inadequate

• Application of EMPs to reduce storm water release• Reevaluate the carrying capacityReevaluate the carrying capacity

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