Hydraulics, Water resources, Irrigation Engineering

Hydraulics deals with mechanics of water (fluid) flow. 
Water resource engineering deals with identification & utilization of available water resources minimizing the loss. 
This also deals with ground water utilization, ground water recharge and rain water harvesting.
Irrigation engineering deals with water management for agriculture purpose. 

Source Of Water

Precipitation 

Precipitation  denotes all form of water that reaches the earth surface from the atmosphere. 

Types

Rainfall
Snow
Drizzle
Glaze
Sleet
Hail
Note: In India, rainfall data is collected everyday at 8:30 am and if the rainfall on a particular day is more than 2.5 mm then that day is called as rainy day.

Rainfall- This is the most dominant form of precipitation in India and it denotes the water droplets with size ranging from 0.5-6mm. On the basis of intensity rainfall is classified as:                 Intensity (mm/Hr)            

 Type

                                                     0-2.5                        Light
                                                     2.5-7.5                  Medium
                                                      >7.5                       Heavy
Snow- It denotes ice crystal having a density of 0.1 gm/cc.

Drizzle- These are fine droplets of water whose size is less than 0.5 mm and intensity is less than 1 mm/hr.

Glaze- When droplets of water comes in contact with cold ground surface(approx. at 0oC) then the droplet of water is converted into ice which is called as glaze. 

Sleet- These are frozen droplets of transparent nature.

Hail- These are lumps of ice whose size is more than 8mm.

Irrigation

Irrigation is the science of artificial application of water to the agricultural field in accordance with crop requirements throughout the period of growth for full maturity of crop.

Advantages:

 Increase in flood production.
 Insuring optimum growth or maximum yield.
 Elimination of mixed cropping.
 Generation of hydropower.
 Improving domestic water supply.

Disadvantages:

Over irrigation may cause water clogging which can reduce crop yield.
Irrigation may lead to creation of climatic condition which favorable for public health diseases.

Types

Surface Irrigation- In this method of irrigation the water directly wet the soil surface that is directly applied for the surface of agricultural field. It can be classified as:

Flow Irrigation: When the water is available at higher elevation and it is supplied to lower elevation by simple action of gravity then it is called as flow irrigation.

Lift Irrigation: If the water is lifted up by some mechanical or manual mean from ground water and then it is applied on the surface of agricultural field then it is called as lift irrigation.

Subsurface Irrigation- In this method, water is directly applied into the root zone of a given crop in agricultural fields so the runoff losses will be very less. That’s why this method is more efficient compare to surface irrigation. It can be classified as:

Natural Subsurface: Leakage water from channel etc. goes underground and during passage through the subsoil, it may irrigate crops on lower elevation. When underground irrigation is achieved by this simple natural process  then its called as natural process.

Artificial process: When a system of perforated pipes or drains is artificial laid below the surface so as to supply water directly into the root zone. Then it is called as artificial subsurface irrigation.