Lectures 2 & 3 ES 657 Autumn 2024-25 PDF

Lectures 2 and 3 ES 657 Lectures prepared by Dr. Subhankar Karmakar Professor Environmental Science and Engineering Department IIT Bombay Powai, Mumbai 400 076, India  Types of Natural Resources …. is the stock that can be drawn from nature …. Natural resources a...

Lectures 2 and 3 ES 657 Lectures prepared by Dr. Subhankar Karmakar Professor Environmental Science and Engineering Department IIT Bombay Powai, Mumbai 400 076, India  Types of Natural Resources …. is the stock that can be drawn from nature …. Natural resources are the components of the environment that can be drawn upon for supporting life Earth is a store house of various resources such as: land, water, soil, minerals, vegetation, forests, fuel, solar energy, etc. Types of natural resources …. can be categorized on the basis of their – (1) Chemical Nature (2) Area of Occurrence (3) Availability or Abundance (4) Origin (5) Utility 2  Types of Natural Resources (1) On the basis of Chemical Nature I. Inorganic resources: air, water, mineral ores II. Organic resources: plants (forests), animals, microbes, fossil fuel (oil, coal, natural gas) III. Mixed resources: soil is the best example (2) On the basis of their Occurrence I. International resources: are available to all countries and have no boundaries (atmosphere with sunlight) II. Multinational resources: are shared by more than one country (Brahmaputra river-common to Tibet, India and Bangladesh) …. Migratory birds also form multinational resources III. National resources: are restricted to a particular country (physical features, geological structure) 3  Types of Natural Resources (3) On the basis of Availability and Abundance I. Inexhaustible resources: not likely to be exhausted by human consumption (solar energy, air, tidal energy) II. Exhaustible resources: likely to be depleted. May be Non-renewable or Renewable a) Non-renewable resources: lack ability of recycling and replacement (fossil fuel - natural, polythene – man made) b) Renewable resources: can be replenished, recycled and reproduced (water, forests, microorganisms) …. A judicious balance is required to be maintained between their exploitation and replenishment 4  Types of Natural Resources (4) On the basis of Origin I. Biotic resources: vegetation with variety of plants, wide variety of animals II. Abiotic resources: composed of non-living matter (land, water, minerals) (5) On the basis of Utility Forest resource Water resource Food resource Energy resource Land resource 5  Depletion of Natural Resources Reasons: People are extracting natural resources at a rate far greater than their capacity to regenerate Continued and careless use of natural resources Life time – is a period along time scale up to which its availability for human use is assured on a global basis Depletion time – is the period along the time scale when the availability of the resource will decrease to such an extent that it is not available to meet human requirements 6  Depletion of Natural Resources Rapid depletion time : policy of extract use and throw away Production Extended depletion time : proper management for waste reduction Indefinite depletion time : involve prevention of wastage and recycling Time 7  Water Resources Water is the only inorganic liquid that occurs naturally on this earth Sources 97% in Oceans 2% is locked in the form of ice 1% is available as fresh water Most of the ocean water is contained in Pacific ocean. Altantic ocean is roughly ½ of the size of the Pacific ocean In India, total surface flow per year is about 1,800 cu. km. About 9.86% of the total fresh water resources is in the form of ground water 0.3% of the total volume of water of hydrosphere is available for human use 8  Water Resources Management – An example of Optimal Water Allocation Source: Mujumdar et al. (2004) N different crops 2 seasons – Rabi & Kharif Reservoir Deterministic & known River supply of water Main Canal Distributary 2 1 3 Branch Canal N Crops An irrigation reservoir system 9  Water Resources Management – An example of Optimal Water Allocation Influencing factors : Crop Areas, Rainfall, Soil Moisture, Irrigation Supply, Time of the year, PET (Potential Evapotranspiration), Crop sensitivity to deficit supply, Competition among crops for water Objective: The objective is to deliver water to the farmers in such a manner, to ensure maximum agricultural production using optimal quantity of water which is delivered in a predetermined schedule fixed for each farmer 10 Water Resources Management – An example of Optimal Water Allocation Real time irrigation water scheduling 11  Water Resources Management – An example of Optimal Water Allocation Objective Function: Maximization of overall crop yield in the command area Soil Moisture Balance AET-PET Relationship Constraints Availability Constraint Minimum Allocation to Each Crop Non-negativity of all variables when linear 12 Water Resources Management – An example of Optimal Water Allocation Optimal Water Allocation for a particular Crop ‘P’ 13 Water Resources Management – An example of Optimal Water Allocation Optimal Water Allocation for a particular Crop ‘P’ (with area updation) 14  Water Resources – few interesting websites Ministry of Water Resources, GoI: http://wrmin.nic.in/ Water Quality Assessment Authority: http://wqaa.gov.in/ Central Water Commission: http://cwc.gov.in/ Central Ground Water Board: http://cgwb.gov.in/ Central Water and Power Research Station: http://cwprs.gov.in/ National Water Development Authority: http://nwda.gov.in/ 15 Hydrology and Hydrologic Cycle 16 Hydrology and Hydrologic Cycle Hydor + logos (Both are Greek words) “Hydor” means water and “logos” means study. Hydrology is a science which deals with the occurrence, circulation and distribution of water of the earth and earth’s atmosphere. Hydrological Cycle: It is also known as water cycle. The hydrologic cycle is a continuous process in which water is evaporated from water surfaces and the oceans, moves inland as moist air masses, and produces precipitation, if the correct vertical lifting conditions exist. 17 Hydroclimatology …. provides a systematic structure for analysing how the climate system causes time and space variations (both global and local) in the hydrologic cycle. …. Changes in the relationship between the climate system and the hydrologic cycle underlie floods, drought and possible future influences of global warming on water resources. 18 Hydrologic Cycle 19 (climateofindia.pbworks.com) The hydrologic cycle is a conceptual model that describes the storage and movement of water between the biosphere, atmosphere, lithosphere, and the hydrosphere. 20 Source: Wurbs and James, 2002 Stages of the Hydrologic cycle ❖ Precipitation ❖ Infiltration ❖ Interception ❖ Depression storage ❖ Run-off ❖ Evaporation ❖ Transpiration ❖ Groundwater 21 22 Precipitation Classification of Precipitation events  Based on the “mechanism” by which air is lifted. Frontal lifting: Warmer air is forced to go above cooler air in equilibrium with a cooler surface. Orographic lifting: Air is forced to go over mountains (and it’s the reason why windward slopes receive more precipitation). Convective Lifting: Warm air rises from a warm surface and progressively cools down. Cyclonic Lifting: A cyclonic storm is a large, low pressure system that forms when a warm air mass and a cold air mass collide. 23 Precipitation Forms of precipitation Rain Water drops that have a diameter of at least 0.5 mm. It can be classified based on intensity as, Light rain ➔ up to 2.5 mm/h Moderate rain ➔2.5 mm/h to 7.5 mm/h Heavy rain ➔ > 7.5 mm/h Snow Precipitation in the form of ice crystals which usually combine to form flakes, with an average density of 0.1 g/cm3. Drizzle Rain-droplets of size less than 0.5 mm and rain intensity of less than 1mm/h is known as drizzle. 24 Precipitation Forms of precipitation Contd… Glaze When rain or drizzle touches ground at 0oC, glaze or freezing rain is formed. Sleet It is frozen raindrops of transparent grains which form when rain falls through air at subfreezing temperature. Hail It is a showery precipitation in the form of irregular pellets or lumps of ice of size more than 8 mm. 25 Precipitation Presentation of rainfall data ❖ Hyetograph Plot of rainfall intensity against time, where rainfall intensity is depth of rainfall per unit time ❖ Mass curve of rainfall Plot of accumulated precipitation against time, plotted in chronological Rainfall Mass Curve order. ❖ Point rainfall It is also known as station rainfall. It refers to the rainfall data of a station 26 Precipitation Mean precipitation over an area The following methods are used to measure the average precipitation over an area: 1. Arithmetic mean method 2. Thiessen polygon method 3. Isohyetal method 4. Inverse distance weighting 1. Arithmetic Mean Method Simplest method for determining areal average P1 N 1 P= N P i =1 i P2 P3 where, Pi : rainfall at the ith raingauge station N : total no: of raingauge stations  Thank you [email protected] 37