Hydrograph

·         Hydrograph represent the relation between instantaneous discharge and time at a given point on the stream.

·         It shows integrated effect of physiographic and meteorological condition on runoff (discharge) from a catchment.

           Components of Hydrograph

·     

·         Uses of Hydrograph

§  In flood damage mitigation by structural and non-structural measures.

§  In flood forecasting.

§  In design of hydraulic structures like dam, spillway, water convey structure etc.

 Hydrograph depends:

·         Meteorological factors :-

§  Rainfall intensity and pattern

§  Areal distribution or rainfall over the basin

§  Size and duration of the storm event

·         Physiographic or watershed factors :-

§  Size and shape of the drainage area

§  Slope of the land surface and channel

§  Channel morphology and drainage type

§  Soil types and distribution

§  Storage detention in the watershed

§  land use and land cover

Factor affecting shape of hydrograph

·         The Drainage Basin

·         Shape of the drainage basin

·         It influences the time taken by water to reach the outlet from farthest point and hence affect the time after which peak discharge attained.

·         Basin A will yield peak discharge early because most of the point are near to the basin outlet.

·         Basin B will have late peak discharge, because point are far away from outlet of basin.

·         Basin C will have two peak discharge, also called complex hydrograph.

·         For a circular drainage basin, the river’s hydrograph have a steep rising limb, symmetrical and high peak discharge.

·         Reason- in this type of basin all point in drainage basin are at equal distance from river or stream so water can take equal travel time to reach the river.

·         Some other factor based on shape are as follows:

1.    Form factor: it is the ratio of average width of the basin to the axial length.

2.    Compactness Coefficient: it is the ratio of perimeter of the basin to the perimeter of a circle, whose area is same as that of the basin.

                               Compactness Coefficient:             P/(2*pie) 

                                 For circular basin value =1

·         Stream density

·         This is defined as the no. of streams per unit area of the catchment area. If value of stream density is more peak discharge will happen early.

·         Drainage density

·         This is defined as the total length of stream per unit area of the catchment. If value of stream density is more peak discharge will happen early.

·         The size of the drainage basin

·         Large size basin catch more water compare to small size basin so hydrograph resulting from large size basin have high peak compare to small size basin.

·         Hydrograph resulting from small size basin have shorter leg time compare to large size basin.

Reason- in small size basin water can take less time to reach river or basin.

Q_P= k. Aⁿ 

K= constant,     A= Area of catchment, Q_P= Peak discharge

·         Basins slopes

·         Basin having Steep slope give high peak discharge and a short lag time hydrograph.

Reason- water take less travel time on steep steep slope.

·         Soil & Rock Type

·         Non-porous and impervious rocks responsible for high peak discharge and shorter lag time.

·         Porous and permeable rocks/ soil results in low peak discharge and greater lag period.

·         Rainfall intensity

·         More rainwater results in more water in the river or in other word higher discharge. So higher intensity storm or rainfall responsible for higher peak discharge and shorter lag time

·         Effect of wind

·         Direction of wind’

·         Soil moisture condition

·         Land use and land cover

Test For Cement

Laboratory test:

      1. Chemical Composition test

•  Lime saturation Factor (LSF): This is the ratio of Lime% to % of Silica, Alumina and Iron oxide. This value should be in between 1.02-0.66.

                 Cao - 0.7SO3                         

  ( 2.8SiO2+1.2Al2O3+0.65Fe2O3)

• Ratio of % Alumina (Al2O3) to Iron oxide (Fe2O3) shall not be less than 0.66

• Wt. of Insoluble residue shall not be more than 4%

• Wt. of Magnesia (MgO) shall not be more than 6%

• Shall not more than 5% loss on ignition.

2. Normal Consistency Test

• 500 gm of cement @27 0C 90% Humidity   mix  with water( 23-24% wt of cement).

• Fill paste in the mould  having dimension 80 mm dia , 40 mm depth

Types of Precipitation

Precipitation means all forms of water , that reaches the earth surface from the atmosphere.
There are following types of precipitation occurs as per Hydrology engineering in India.

1. Rain
2. Snow
3. Drizzle
4. Glaze
5. Sleet
6. Hail

1. Rain

This is the principle mode of precipitation in India. This denotes water droplets with size varying from 0.5 mm to 6 mm. On the basis of intensity , Rainfall is classified as follows;

Sprinkler Irrigation System

    Image: Sprinkler Irrigation System.

Water is a key factor in increasing agricultural production. About 78% of India's water resources are used for agriculture out of this only 50% is actually used by plants and the remaining water resources are wasted either as deep percolation or as evaporation. Excess irrigation not only reduces crop production and damages soil fertility but also causes ecological hazards like water logging and salinity. With competitive use of water and its increasing scarcity, it has become imperative to economize water use for optimum productivity. This is possible only through improved water management and adopting techniques of irrigation. One such method of modern irrigation is sprinkler irrigation system and is popular among the farmers across the country.

Bogues Compounds Cement

Bogues Compounds: when water is added to cement it react with the ingredients of the cement chemically & results in the formation of complex chemical compounds terms as BOGUES compounds. which are not for simultaneously.

1. Tri-Calcium Aluminate (3CaO.Al2O3 or C3A) -------------------------8-12%

2. Tetra Calcium Alumino Ferrate (4CaO.Al2O3.Fe2O3 or C4AF)----6-10%

3. Tri-Calcium Silicate (3CaO.SiO2 or C3S)---------------------------------30-50%

4. Di-Calcium Silicate (2CaO.SiO2 or C2S)----------------------------------20-45%