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1. INTRODUCTION

2. CONTENT 2 8/29/2024 Add a footer

3. Definition of Hydrometeoroly Hydrometeorology is a branch of meteorology and hydrology that studies the transfer of water and energy between the land surface and the lower atmosphere. Meteorology is the science that studies atmospheric phenomena and weather. It is responsible for predicting and understanding the changes in temperature, humidity, atmospheric pressure, and precipitation, among other factors. Meteorologists use instruments and techniques to collect data, analyze it, and make predictions about weather conditions. 3 8/29/2024 Add a footer

4. Definition of Hydrology Hydro means water, and logy means study. Therefore, in a broad sense hydrology can be defined as a study of water. A more practical definition is given below: Hydrology can be defined as the science that deals with the spacetime characteristics of the quantity and quality of the waters of the earth, encompassing their occurrence, movement, distribution, circulation, storage, exploration, development, and management. These characteristics are determined by the relation of water to the earth. 4 8/29/2024 Add a footer

5. Hydrology was originally practised by many different disciplines, e.g. geology , civil engineering and agriculture . Sciences emphasizing hydrology often use the prefix hydro (hydrogeology, hydrobiology, hydrometeorology, etc.). Other allied sciences are for example soil science, fluid mechanics, economy, chemistry, physics and statistics. 5 8/29/2024 Add a footer

6. Classification of hydrology according to its association with other branches of science. (Source: Singh, 1994) 6 8/29/2024 Add a footer 6 8/29/2024

7. Classification of hydrology according to methods of solution. (Source: Singh, 1994) 7 8/29/2024 Add a footer

8. Scope of Hydrology Water is one the most valuable natural resources essential for human and animal life, industry and agriculture. It is also used for Power generation, navigation and fisheries. Tremendous importance is given to the hydrology all over the world in the development and management of water resources for irrigation, water supply, flood control, water-logging and salinity control, Hydro power and navigation 8 8/29/2024 Add a footer

9. Uses of Hydrology in Engineering Engineering Hydrology Helps in the following ways: Hydrology is used to find out maximum probable flood at proposed sites e.g.. Dams. The variation of water production from catchments can be calculated and described by hydrology. Engineering hydrology enables us to find out the relationship between a catchment’s surface water and groundwater resources 9 8/29/2024 Add a footer

10. Uses of Hydrology in Engineering The expected flood flows over a spillway, at a highway Culvert, or in an urban storm drainage system can be known by this very subject. It helps us to know the required reservoir capacity to assure adequate water for irrigation or municipal water supply in droughts condition. It tells us what hydro-logic hardware (e.g.. rain gages, stream gauges etc ) and software (computer models) are needed for real-time flood forecasting 10 8/29/2024 Add a footer

11. HYDROLOGIC CYCLE

12. What is Hydrologic Cycle Hydrologic cycle is the process of transfer of moisture from the atmosphere to the earth in the form of precipitation, conveyance of precipitated water by streams and rivers to ocean and lakes etc., and evaporation of water back to the atmosphere. 12 8/29/2024 Add a footer

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14. Hydrological Processes Precipitation Evaporation Transpiration Infiltration 14 8/29/2024 Add a footer Overland flow Surface Runoff Groundwater outflow

15. The water holding elements of the hydrological cycle are: Atmosphere Vegetation Snow packs Land surface 15 8/29/2024 Add a footer Soil Streams, lakes and rivers Aquifers Oceans

16. Precipitation is all forms of moisture falling to the ground, i.e. rainfall, snow, hail, etc. Runoff is that part of precipitation that appears as stream flow. Types of Run-off a. Surface run-off - A run-off that which travels over the ground surface and through the channels to reach the basin outlet. b. Interflow/Subsurface run-off- A run-off which infiltrates into the soil surface and moves laterally through the upper soil horizons towards streams as perched groundwater above major groundwater level. c. Base Flow – When the water after precipitation infiltrated into the soil and merges with the water table and flows into the stream then it is known as base runoff. The movement of water in this is very slow. 16 8/29/2024 Add a footer

17. Evaporation – is a process by which precipitation is returned to the atmosphere as vapor . Transpiration – is a process by which plants dissipate water into the atmosphere from leaves and other surfaces. Evapotranspifration – is the combination of evaporation of water from wet plant and soil surfaces and the transpiration of water in plants. Interception – is that part of precipitation at the beginning of a storm that is stored in vegetal cover and does not contribute to run-off. Infiltration – is the movement of water through the soil surface into the soil profile. Percolation – is the movement of water through the soil profile. 17 8/29/2024 Add a footer

18. COMMON HYDROLOGIC TERMS

19. Common Hydrologic Terms Watershed (w/s) – The area contained within a divide above a specified point on a stream. It can also be called drainage area, subarea, basin or catchment area. Time of concentration (T c ) – The time it takes water to move from the hydraulically most distant point in a watershed to a watershed outlet, usually expressed in hours. It is used to estimate peak discharge or to develop a hydrograph. Hydrograph – A graph showing the discharge, velocity, or other property of water with respect to time. Usually we work with discharge hydrographs, where the points on the hydrograph are expressed in cfs . 19 8/29/2024 Add a footer

20. Common Hydrologic Terms Peak discharge ( q p ) – the maximum discharge rate for a given hydrograph or flood event, usually expressed in cfs . Run-off (Q) – That portion of precipitation which appears as streamflow, usually expressed in inches. Velocity (V) – The distance traveled divided by the time required to travel that distance, usually expressed in feet per second (ft/s). Initial abstraction ( I a ) – The portion of precipitation occurring before surface run-off begins, usually expressed in inches. It consists mainly of interception, infiltration, and depression storage. 20 8/29/2024 Add a footer

21. Common Hydrologic Terms Frequency – An expression or measure of how often a hydrologic event of given size or magnitude should, on the average, be equaled or exceeded. It is usually expressed in years. For example A 50-year frequency flood will be equaled or exceeded in size, on the average, once in 50 years. 21 8/29/2024 Add a footer

22. HYDROLOGICAL DATA

23. Hydrological Data Weather and Climate records: Data about temperature, humidity, radiation, wind etc , since these directly hydrological parameters. Precipitation data : The study of precipitation forms a major portion of the subject of hydro-meteorology. The precipitation data helps in predicting run-off volume and its peak. Stream flow data: This helps in the planning of reservoirs, design of spillways, bridges, culverts, levees, and water power development and installation. The data is utilized for determination of maximum (peak) flood, flood magnitude, flood frequency, reservoirs elevations, water budget etc. 23 8/29/2024 Add a footer

24. Hydrological Data Evaporation and Transpiration data: This data is required for determining ( i ) water budget for the river basin; (ii) reservoir capacity for water resources development ; and (iii) evaporation suppression technique Infiltration characteristics of the area : This data is required for determining rainfall excess and run-off computation. Ground water characteristics: This helps in estimation and location of groundwater reservoir , for ground water development. 24 8/29/2024 Add a footer

25. Thank You 