Lake classification and Morphometry.pptx

To study about classification of lakes and Morphometry

1. FS-115 LIMNOLOGY M.BOOBALAN 1 ST YEAR BFSc Dr.M.G.R FC&RI , Thalainayeru Classification of Lakes and morphometry

2. TEMPERATURE Most important factor Diurnal and seasonal variations are very much common Diurnal variation range of 4.8 to 5oC has been recorded in a tropical pond

3. CLASSIFICATION Tropical lakes : In which surfac temperature are always above 4 o C Temperate lakes : In which surface temperature vary above and below 4 o C Polar lakes : In which surface temperature never goes above 4 o C

4. Source of heat for evaporation Sun Water Surroundings

5. Rate of evaporation Temperature Relative amount of free surface area of the water Vapour pressure Barometric pressure Amount of wind action Quality of water ie . fresh or salt Convection Thermal Conductivity

6. Thermal stratification in lakes Different layers develop in a large lake, due to temperature changes with depth

7. Summer stratification Epilimnion a) It is upper layer of water. b) It is warmer layer. c) The temperature of this layer fluctuates with the temperature of the atmosphere. It will be about 27°C to 21°C.  Hypolimnion a) It is the bottom layer of water. b) At this layer, water will be cool. c) The temp is between 5°C and 7°C.  d) It is a stagnant column of water.  Thermocline ( metalimnion ) a) It is the middle layer. b) The temperature is in between the temp of the upper layer and that of the lower layer. c) It is characterized by a gradation of temperature from top to bottom. d) It is also called transition zone.

8. Morphometry The study that deals with measurement of morphological features of the basin of a body of water and its included water mass is known as morphometry . Because may fundamental ecological relations are directly dependent upon structural relations of water it is necessary to make measurements of various morphological features. Following general and morphometric information should be generated before studying structural and functional attributes of the system

9. General information Type: The type of body of water viz. lake, pond, marsh, swamp, well, spring, stream, river, estuary, should be noted. Location: The locality, latitude, longitude and altitude at which the study area is situated should be noted from authentic maps.

10. Historical background : Collect the information pertaining to geological history of the basin and surroundings of natural waters. For artificial bodies the construction or excavation details are of importance. General physiography: Salient physiographical features related to basin, bank and catchment area of the body of water should be noted. This includes the features of bed-rock, coarse gravel, fine gravel, debris, mud, marl, peat, sand, silt, clay, marshy, swampy etc. Continued…

11. Area : The surface area for water-spread can be calculated from a shore – line map of the body of water. Bathymetry : A bathymetric or contour map is one which denotes the depth at different points in the body of water. Maximum length: It is the length of line connecting two most remote extremities of the body of the water

12. Maximum length: It is the length of line connecting two most remote extremities of the body of the water. Maximum effective length: It is the length of line connecting two most remote extremities of the body of water along which wind and wave actions occur without any kind of interruption. Maximum length and maximum effective length may be the same in most cases.

13. Maximum width: It is the length of straight line connecting most remote transverse extremities of a body of water. Maximum effective width : It is the length of straight line connecting more remote transverse extremities of a body of water along which wind and wave actions occur without any kind of land interruption. Mean width or Mean breadth ( b ) : It is equal to the area divided by maximum length ( b ) = a/l

14. Depth: It is the vertical distance between the surface and the underlying bottom. Maximum depth: It is the depth measured at the deepest point. Mean depth: It is calculated by dividing the volume of the body of water by its surface area. ( z ) = v/a = Volume / area. Outline map: Representing the outline structure of a lake in a plane surface is called outline map.

15. Topographical map: Representing various layers of lake basin on a flat surface is called topographical map. Instruments Platometer or Planimeter  is an instrument used in surveying to compute the area of any given plan. Rotometer A hand-held measuring device incorporating a small wheel that can be rolled over a map or plan, the revolutions of the wheel giving the notional distance travelled on the ground.