Water Conservation & Indian Monsoon rain

PPT on Monsoon

1. Monsoon: Mechanism, Impact, and Prediction Understanding the Role of Monsoon in India

2. Forms of Precipitation Formound Description Rain 6mm >Water droplets >0.5mm Intensity(mm/h) Type Trace to 2.5 Light Rain 2.5-7.5 Medium Rain Greater than 7.5 Heavy Rain Snow Ppt in the form of Ice crystal Occurs in Himalaya region

3. Forms of Precipitation Form Description Drizzle Fine sprinkle of Water drops of size < 0.55mm & Intensity < 1mm/ hr Glaze Drizzle or rain coming in contact with ground at 0 deg Celsius

4. Forms of Precipitation Form Description Sleets Ice pellets of size 1mm-4mm Formed due to freezing of falling rain Hail Balls Or irregular lumps of ice pellets 5mm -8mm Occurs during violent thunderstorm

5. Forms of Precipitation Form Description Snow flakes Fused ice crystals Dew Formed on earth surface as a result of cool surface in night

6. Forms of Precipitation Form Description Fog Thin cloud of Varying size (Morning) Mist Frost Thin Fog having numerous water droplets Feathering deposits of ice on surface

7. Seasons in India South West Monsoon-[June to Sept]- Orographic Precipitation Post Monsoon- [Oct-Nov] -Tropical Cyclone Cold Weather, Winter Monsoon [Dec-Feb]- Extra-Tropical Cyclone Summer, Pre Monsoon [Mar-May]- Convective Precipitation

8. Orographic precipitation Orographic precipitation ,  rain , snow, or other precipitation  produced when moist air is lifted as it moves over a mountain range. As the air rises and cools,  orographic  clouds form and serve as the source of the  precipitation , most of which falls upwind of the mountain ridge South West Monsoon-[June to Sept]- Orographic Precipitation

9. Tropical Cyclone Post Monsoon- [Oct-Nov] -Tropical Cyclone

10. Extra-Tropical Cyclone Frontal rain happens when cooler air and warmer, humid air meet in a weather front. The less dense warm air rises and condenses forming clouds. These clouds grow and eventually create rain. Cold Weather, Winter Monsoon [Dec-Feb]- Extra-Tropical Cyclone

11. Convective Rainfall                                      Convectional rainfall. When the land warms up, it heats the air above it. This causes the air to expand and rise. As the air rises it cools and condenses. If this process continues then rain will fall Summer, Pre Monsoon [Mar-May]- Convective Precipitation

12. Factors Influencing South-West Monsoon - Differential heating of land & water - Inter Tropical Convergence Zone ( ITCZ ) shift - High-pressure zone over Indian Ocean - Tibetan Plateau heating - Jet streams influence - Southern Oscillation & El Niño

13. Mechanism of Monsoon 1. Onset in June-July: ITCZ moves north, moist winds bring rain 2. Two branches: - Arabian Sea (Heavy rain over Western Ghats) - Bay of Bengal (Rain in NE & central India) 3. Breaks in Monsoon: Dry spells due to trough movement 4. Retreating Monsoon (Oct-Nov): Skies clear, temperature rises, cyclones form

14. Types of Monsoons in India: Southwest Monsoon (June-Sept) – Brings 75% of India's annual rainfall. Northeast Monsoon (Oct-Dec) – Affects eastern coast with post-monsoon rainfall. Impact on Water Availability: Southwest Monsoon – Fills rivers, reservoirs, groundwater. Northeast Monsoon – Supports Tamil Nadu & Andhra Pradesh. Variability – Deficits cause droughts; excess rains cause floods.

15. Monsoon Low and Its Influence on the Monsoon What is a Monsoon Low? - A low-pressure system that forms over land due to intense heating. - Drives moisture-laden winds from the ocean towards the land. - Typically found over the Bay of Bengal and central India. How Does It Influence the Monsoon? Enhances rainfall by strengthening monsoon currents. Pulls in moist air, intensifying the monsoon system. Affects regional variability with wet and dry spells. Westward movement increases rainfall; weakening causes dry conditions .

16. Significance of Dry Spells and Wet Spells What are Dry and Wet Spells? Dry Spells – Periods of little to no rainfall. Wet Spells – Continuous days of rainfall. Why are They Important? Agriculture – Dry spells impact crops; wet spells cause flooding. Water Management – Helps in irrigation and storage planning. Climate Studies – Key for predicting droughts and floods.

17. Key Indicators of Monsoon Withdrawal How Do We Know the Monsoon is Retreating? Decrease in rainfall. Wind pattern shifts from moist to dry winds. Drop in humidity. Clear skies & temperature rise. Why is This Important? Helps in water resource management. Affects agriculture planning. Important for weather forecasting and disaster preparedness.

18. Withdrawal of SW Monsoon a) Withdrawal from extreme north-western parts of the country is not attempted before 1st September. b) After 1 st  September: The following major synoptic features are considered for the first withdrawal from the western parts of NW India. i ) Cessation of rainfall activity over the area for continuous 5 days. ii) Establishment of anticyclone in the lower troposphere (850 hPa and below) iii) Considerable reduction in moisture content as inferred from satellite water vapour imageries Further Withdrawal from the Country i ) Further withdrawal from the country is declared, keeping the spatial continuity, reduction in moisture as seen in the water vapour imageries and prevalence of dry weather for 5 days. ii) Withdrawal of SW monsoon is from the southern peninsula and hence from the entire country only after 1st October, when the circulation pattern indicates a change over from the southwesterly wind regime.

19. Impact of Monsoons on Life in India Positive: - Supports agriculture (64% population depends on it) - Hydro power & reservoirs fill - Supports diverse crops & culture Negative: - Droughts & floods disrupt life - Soil erosion & landslides damage infrastructure - Economic & social instability

20. Monsoon Prediction in India - Traditional: Snow cover method Modern: - Statistical & Numerical models - Weather monitoring (IMD, satellites, radars) - Indo-US expedition for better forecasting Lower snow cover increases land heating, strengthens winds, and results in stronger monsoon rains . Higher snow cover cools the land, weakens monsoon winds, and leads to weaker rainfall .

21. Global Warming & Future Challenges - Climate Change = More extreme rainfall & unpredictability - Solutions: Invest in AI & supercomputers for forecasting Improve water management Stronger climate policies

22. Water Resources in Karnataka A Discussion on Surface Water, Distribution, Challenges, and Solutions

23. Major Sources of Surface Water in Karnataka - Rivers : Krishna, Cauvery, Godavari, Tungabhadra - Lakes and Reservoirs : Almatti , Kabini , Harangi - Tanks and Ponds : Used for irrigation and drinking water - Rainwater : Seasonal source for agriculture - Groundwater Recharge : Dependent on surface water availability

24. India’s WATER SECURITY ? ANNUAL RAINFALL Min. = 100 mm : Western Desert Max. =11000 mm : North-Eastern Region A vg. = 1 170 mm : All India WATER RESOURCES ON INDIA (In BCM) Total Precipitation : 4000 T otal W ater A vailabili t y : 1869 Total Utilisable Water S urface W ater - 690 Ground Water- 433 = 1123 CAN INDIA ENSURE WATER SECURITY? India has only 2.4% of the world’s total land area (328 Mha) 1 8 % of the world’s population 4% of the total available fresh water Per capita water availability is expected to decrease to 662 m 3 by 2050

25. Consequences of Reduced Surface Water Flow - Decline in aquatic biodiversity - Habitat loss for fish and other species - Increased water temperature affecting ecosystems - Reduced water availability for agriculture and drinking - Higher salinity and pollution concentration

26. CONJUNCTIVE USE: WHAT DOES IT MEAN ? India can tackle food & water security along with the associated issues in a canal command through ‘Conjunctive Use of Water’ . Conjunctive use of water refers to optimal allocation of groundwater along with surface water in any irrigation system (FAO). Mixed for productive use SURFACE WATER GROUNDWATER Management of surface water and groundwater resources in a coordinated manner such that the total yield of such a system over a period of years exceeds the sum of the yields of the separate components of the system resulting from an uncoordinated operation .

27. Reclamation of waterlogged saline soils : A case study of Kagadhal village of Malaprabha basin Soil salinity is a major problem in canal command areas. The village of Kagadal , located in Parasgad taluka of Belagavi district in Karnataka, has faced a major challenge of soil salinity and waterlogging for 25–30 years. Approximately 70% of the cultivable area of the village was affected by soil salinity, and the land, which was once highly productive, was partially cultivated or left barren for many years. The use of salt-tolerant crops, land leveling, and drainage systems are only a few of the strategies that have been created to address these issues. Parameter Expected Observed Remarks Electrical Conductivity Non-saline soil: EC < 2 dS /m > 4 ds/m Soil is saline. High salinity can affect plant growth by making it harder for plants to absorb water, leading to stress and reduced yields pH Slightly acidic to neutral: pH 6.5 - 7.5 8.76 Soil is highly alkaline. High alkalinity can lead to nutrient deficiencies because certain nutrients become less available to plants in alkaline conditions. Sodium Non-sodic soil: ESP < 6% > 15% High sodium levels can deteriorate soil structure, reducing permeability and aeration, and can be toxic to plants.

28. Necessity of irrigation Uneven distribution of rainfall Uncertentity of Rainfall Irregularity of rainfall Seasonality of rainfall Multiplicity of crops Specialty of crops Commercialized crops Nature of soil

29. Key Factors Contributing to Uneven Water Distribution Varied Rainfall Patterns : Western Ghats receive heavy rain, interior regions are dry Topography : Rivers originate in highlands, limiting uniform distribution Human Activities : Excessive groundwater extraction and irrigation practices Climate Change : Increasing unpredictability in monsoon patterns

30. Factors Influencing Rainfall Variation in Karnataka Monsoon Influence : Southwest monsoon affects coastal areas more Orographic Effect : Western Ghats block rain, leading to rain shadow regions Latitude and Wind Patterns : Impact seasonal variations Urbanization and Deforestation : Affect local weather and rainfall patterns

31. Challenges Related to Water Quality in Karnataka - Industrial Pollution : Chemicals and heavy metals contaminating rivers - Agricultural Runoff : Pesticides and fertilizers polluting water bodies - Sewage and Waste Disposal : Untreated wastewater affecting urban water sources - Groundwater Contamination : Fluoride and nitrate levels exceeding limits

32. Measures to Improve Water Quality - Strengthening wastewater treatment and sewage systems - Promoting sustainable agricultural practices - Implementing strict pollution control laws - Encouraging rainwater harvesting and groundwater recharge - Public awareness and community participation in water conservation