CARRYING CAPACITY 2/ /9/2011 DR. RAJIB BHATTACHARJYA

Transcription

1 CARRYING CAPACITY 2/ /9/ DR. RAJIB BHATTACHARJYA

2 EASTER ISLAND Located 3500 kilometers off the coast of Chile It is the world s remotest inhabited island. Most advanced d society with great cultural heritage. 2

3 2/9/2011 Easter Island Statue, built around 700 AD 3

4 EASTER ISLAND Discovered by Polynesians ~ A.D Population grew to several thousands Used trees for canoes to hunt dolphins Used wood for cooking Also ate birds, eggs, vegetables Resources (trees) depleted No canoes, no dolphins Warfare over land, food resources Population fell to 100 when visited by a Dutch in

5 BASICS ABOUT POPULATION GROWTH The environment has a carrying capacity for every organism based on the available resources If resources are abundant and readily available, then a population will show exponential growth 5

6 2/9/2011 During exponential growth the increase in population size varies with the number of individuals present Increase is gradual at first, but rises sharply as more individuals become part of the population Unlimited resources allow everyone e to 6 reproduce!

7 ENVIRONMENTAL RESISTANCE FACTORS Populations will continue to grow exponentially until they come up against limiting factors or resistance factors Resource limitations Food, nutrients, water, sunlight Shelter, space Competition from other species Predation Waste accumulation 7

8 LOGISTIC GROWTH 2/9/2011 In the real world resources are often limiting The first part of the growth resembles exponential growth But over time, the population size levels off in logistic growth at a point called the carrying capacity 8

9 The carrying capacity of the environment represents the maximum number of individuals of a particular species that an area can support indefinitely without degrading CARRYING CAPACITY 9

10 CARRYING CAPACITY 2/9/2011 Natural populations seldom approach carrying capacity smoothly Or stay at the carrying capacity once reached They usually fluctuate around the carrying capacity Overshooting it or falling below depending on resources 10

11 ENVIRONMENTAL CARRYING CAPACITY A population gradually increase to the maximum size that available resources will support the environment s carrying capacity. Thereafter, the population fluctuates around this size with good and bad cycles e.g. rainfall. What happens if something drastically reduces this population? Popula ation size Carrying Capacity = 10, What could 0 do that?? Time (years) 11

12 RECOVERY VS. REDUCED CAPACITY If the population is reduced because of a time catastrophe e.g a 8000 long drought then over time it will recover 2000 back to its former size. 0 But if the overall environment is reduced e.g. half the forest is cut down 8000 then the population 6000 adjusts to a new, lower 4000 carrying capacity Population size Population size Recovery to Carrying Capacity = 10, Time (years) Carrying Capacity reduced to 5, Time (years)

13 CARRYING CAPACITY human population recovered after the Black Death in fact the global human p population p has not yet reached carrying capacity. Salmon S l fish fi h population l ti increases, then had their habitat reduced by y dams and pollution. The population had to adjust to a much lower carrying capacity. 2/9/ So 13

14 What is The Limit 2/9/

15 URBAN CARRYING CAPACITY CONCEPT Carrying capacity can be defined as the number of individuals that 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. 15

16 SUSTAINABILITY Resource harvest sustainability refers to the quantity of the resource that is harvestable indefinitely. Ecosystem sustainability refers to maintaining an ecosystem s essential functions and properties while harvesting an ecosystem resource. Sustainable economy maintains its level of activity over time. Sustainable development requires the integration of economic and social growth and environmental protection. 16

17 FACTORS EFFECTING URBAN CARRYING CAPACITY Environmental and ecological Urban facilities Carrying Capacity Institutional Public perception p 2/9/

18 ENVIRONMENTAL CARRYING CAPACITY Determining factors for environmental carrying capacity of an urban area are soil, slope, vegetation, wetlands, scenic resources, natural hazards, air and water quality, and energy availability, etc. 18

19 URBAN FACILITY CARRYING CAPACITY Housing, water supply, sewage, waste treatment, road network, railway networks, health care, educational facilities, employment facilities, etc. are some of the factors that measure the carrying capacity of urban area. 19

20 PUBLIC PERPETUAL CARRYING CAPACITY The level of public awareness, which generally includes human attitudes, values, behavior, habits etc. 20

21 INSTITUTIONAL CARRYING CAPACITY The institutional carrying capacity will be governed by the governmental structure, financial stability, economy and cultural limits on environmental decision making, etc. 21

22 FRAMEWORK FOR CARRYING CAPACITY CALCULATION FOR HILLY AREA Step1: Delineation of hilly area From the Master Plan Step2: Demarcation of non developable areas based on analysis of physical characteristics of the urban hilly area and provision of different statute Step3: Determination of area required for different infrastructure 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 be calculated iteratively 22

23 FRAMEWORK FOR CARRYING CAPACITY CALCULATION FOR HILLY AREA Step4: From the above calculation net area available for residential development will be calculated 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, amount of daily solid waste generated, market demands, cultural activities and climate in the area 23

24 Step6: Based on above calculations carrying capacity of the study area may be calculated l as stated t below: CC = (AH (A NDA + AIF CC ) x FAR/S 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) 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 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 24

25 GIS APPLICATION 2/9/2011 Waterways Natural Depression Rocky land High Slope Land Total Watershed Area 25

26 2/9/2011 Total Developable area of the Watershed Non developable area of the Watershed 26

27 DETERMINATION OF CARRYING CAPACITY BASED ON HYDROLOGICAL CAPACITY OF THE WATERSHED Determination of net density : Carrying Capacity (in persons) Suitable Residential Area Check for adequacy of drainage system, sewerage system etc which were not explicitly considered during carrying capacity calculation 27

28 EXAMPLE FOR DRAINAGE ADEQUACY Waste water generation from the proposed carrying capacity Strom water + generation from the watershed Check adequacy of drainage system If inadequate Application of EMPs to reduce storm water release Reevaluate the carrying capacity 28

29 2/9/