HYDROLOGY
CENG 80B
ENGR.ALVIN DELIRO
Course Description:
The course deals with the topics on water resources and losses; infiltration effects
on evaporation stream and flow; hydrographs; precipitation, flood frequency,
reservoirs, protection, water conservation, flood water supply management and
recent technologies. The course describes the details in designing ground water
wells and irrigation systems.
Introduction to Hydrology
Hydrology -It is the science that deals with the occurrence, circulation and distribution of
water of the earth and earth’s atmosphere. - The science of water
The History of Hydrology
Ven Te Chow Classifies the history of hydrology into eight periods as:
1. Period of Speculation-Prior to AD 1400
2. Period of Observation- 1400-1600
3000
BCground
water
3. Period of Measurement- 1600-1700
development
through
wells
was
4. Period of Experimentation- 1700-1800
known to people of Indus Valley
5. Period of Modernization- 1800-1900
4000 BC- A dam was built across
6. Period of Empiricism- 1900-1930
the Nile river
7. Period of Rationalization- 1930-1950
8. Period of Theorization- 1950-to-date
Application/ Uses of Hydrology
1. Hydrology is used to find out maximum probable flood at proposed sites e.g. Dams.
2.The variation of water production from catchments can be calculated and described by
hydrology.
3.Engineering hydrology enables us to find out the relationship between a catchment's
surface water and groundwater resource
4.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
5. Determining the water balance of a region.
6. Determining the agricultural water balance.
7.Mitigating and predicting flood, landslide and drought risk.
8. Real-time flood forecasting and flood warning.
9. In Designing irrigation schemes and managing agricultural productivity.
Designing riparian restoration projects relating to wetlands adjacent to rivers and streams.
Part of the hazard module in catastrophe modeling
10. Designing Bridges
11. Designing sewers and urban drainage system.
12. Providing drinking water.
13.Analyzing the impacts of antecedent moisture on sanitary sewer systems.
14. Predicting geomorphologic changes, such as erosion or sedimentation.
15.Assessing the impacts of natural and anthropogenic environmental change on water
resources.
16.Assessing contaminant transport risk and establishing environmental policy guideline
In Engineering Hydrology we apply scientific knowledge and mathematical principles to
solve water-related problems in society: problems of quantity, quality and availability.
Mathematical models of all Hydrological phenomena are made.
Hydrologic Cycle
Describes the continuous movement of water on, above and below the surface of the
Earth. The water moves from one reservoir to another. The water cycle involves the
exchange of energy, which leads to temperature changes. The evaporative phase of the
cycle purifies water which then replenishes the land with freshwater
The Process of Hydrological Cycle
Physical Processes
1. Evaporation
- The transformation of water from liquid
to gas phases as it moves from the ground
or bodies of water into the overlying
atmosphere.
Evapotranspiration- is the sum of
evaporation and plant transpiration from
the Earth's land and ocean surface to the
atmosphere.
2. Condensation
- The transformation of water vapor to liquid water droplets in the air, creating
clouds and fog.
3. Precipitation
– Condensed water vapor that falls tothe Earth’s surface. Rain, snow, hail,
fog, drip etc.
4. Transpiration
- The release of water vapor from plantsand soil into the air. Water vapor is a gasthat
cannot be seen.
5. Infiltration
- The flow of water from the ground surface into the ground.
6. Run-off
- It is the water flowing over the land making its way towards rivers, lakes, oceans etc. as
surface or subsurface flow.
CATCHMENT AREA
-It is the area of the land draining into a stream or a water course at a given location
-Drainage area or drainage basin; watershed
WATER BUDGET EQUATION
EQUA
TION
OF
RAINFALLRUNOFF
RELATIONSHIP