Civil Engineering Orientation Module 5 : Water Resources Engineering Flashcards
is a specialty dealing with the use of water in support of modern living, including the agricultural, industrial, domestic, recreational, and environmental needs.
Water Resources Engineering
The process where water is conserved and neither created nor destroyed
Hydrologic Cycle
occurs when atmospheric moisture becomes too great to remain suspended in the clouds.
Precipitation
greatest source of precipitation, about 90%
Ocean Evaporation
predominant form of precipitation and its distribution over the world or within a country.
Rainfall
is the water that flows across the land surface after a storm event.
Runoff
Portion of the precipitation falling on land surface which does not flow as runoff gets stored as either water bodies like Lakes, Reservoirs and Wetlands or as sub-surface water body, called groundwater.
Storage
sub-surface water body.
Groundwater
water infiltrating through the soil cover of a land surface and travelling further to reach the huge body of water underground.
Groundwater Storage
Large, naturally occurring inland body of water.
Lakes
Artificial or natural inland body of water used to store water to meet demands.
Reservoirs
Natural or artificial areas of shallow water or saturated soils that contain or could support.
Wet Lands
Combination of evaporation and transpiration. It includes all evaporation from water and land surfaces, as well as transpiration from plants.
Evapotranspiration
Recuperation of groundwater to increase table elevation.
Groundwater Recharge
Deals with the design of artificial waterways and manage water movement
Hydraulic Engineering
a term that describes both liquid and gas.
Fluid
Results from different molecular bonding condition at the free surface compared to bonds within the liquid.
Surface Tension
enables water to resist tensile stress.
Cohesion
enables water to adhere to another body.
Adhesion
property of liquids that results from surface tension in which the liquid rises up or is depressed down a thin tube.
Capillarity
weight per unit volume
Specific Weight
mass per unit volume.
Density
Liquid is the ratio of its specific weight to that of pure water at a standard temperature and should not be confused with specific weight.
Specific Gravity
Study of water at rest.
Hydrostatics
A simple tube connected to a body of water with its other end open to the atmosphere.
Piezometer
Measures high pressure by a heavy liquid such as mercury.
Manometer
Uplifting force exerted by water on a submerged solid object.
Buoyancy
Study of water in motion.
Hydrodynamics or Hydrokinetics
The rate of change of position of the water particles.
Velocity
The average speed of all the particles crossing an imaginary plane perpendicular to the direction of motion at a particular location along the conduit.
Velocity of Flow
Describes the amount of water passing through an plane per unit time.
Discharge
Smooth flow of water with relatively low velocity.
Laminar Flow
Rougher flow with pulsating crosscurrents within the conduit.
Turbulent Flow
Discharge is unchanged over time.
Steady Flow
Relatively rapid change of discharge.
Unsteady Flow
Cross-sectional area of the conduit remains constant.
Uniform Flow
Change in pipe size and flow.
Nonuniform Flow
Used to describe the energy of water in solving hydraulic problems.
Energy Head
Described as potential energy head and has length units.
Potential Energy
Described as kinetic energy, called velocity head, and also has units of length
Kinetic Energy
Recuperation of groundwater to increase table elevation.
Groundwater Recharge
Potential energy per unit weight of a mass of water due to the height of the water above some datum.
Position Head
Potential energy per unit weight of a mass of water due to the pressure exerted from above.
Pressure Head
Kinetic energy per unit weight of a mass of water due to kinetic energy resulting from its motion.
Velocity Head
Loss of energy per unit weight of a mass of water due to friction and turbulence.
Head Loss
Structures that use hydraulic principles to control the flow of water.
Hydraulic Devices
Hole in the wall of a container through which water may flow.
Orifice
Point where flow lines are parallel and closest together
Vena Contracta
Regulates the flow of water out of an impoundment or reservoir.
Weir
Study of the mechanics of water flowing in open conduits.
Open Channel Hydraulics
This is the major cause of flooding extensive areas as a result of heavy rains in the catchment areas as well as local areas thereby increasing the river levels.
River Flooding
This result due to heavy rains in hilly areas which cause local rivers and small streams to rise to dangerous levels within a short period of time say 6 to 12 hours. Heavy and continuous rains in local areas can cause flash floods.
Flash Floods
Local heavy rains up to 100 mm or more in a day over the city and larger towns can cause damaging and disruptive flooding due to poor or choked drainage and rapid runoff.
Urban Flooding
This result mostly due to tropical disturbances, developing to cyclones and crossing surrounding coastlines. Cyclone induced storm surges have devastating consequences in coastal areas and such surge induced floods may extend many kilometers inland.
Storm Surge or Tidal Flooding
Due to poor maintenance and due to exceptionally high precipitation a severe flood may result causing failure of the dam. This causes a surging water front travelling with high velocity causing destruction of properties and loss of life.
Floods Arising due to Failure of Dam
Can be classified into short-term and long-term measures depending on the nature and extent of flooding and local conditions
Flood Management Measures
Adopted for giving quick results when immediate relief to some pockets or locations is felt necessary.
Short-term Measures
The effectiveness of short-term effects are dependent on these.
Long-term Measures
Keep water away from the potential damage areas.
Modify Flooding by Structural Means
Keep people away from inundated areas
Flood Forecasting
Regulations are framed to avoid undesirable or unwise rise of food plains.
Modify Susceptibility to Flood Damage
Provided in storage dams for safe disposal of the excess water flowing into the reservoir after it has filled up.
Spillways
Permit controlled release of surplus water in excess of the reservoir capacity.
Controlled Crest Spillway
Come into action immediately after the water level reaches the crest of the spillway.
Uncontrolled or Automatic Crest Spillway
Act as orifices under partial control of gates and as open crest weirs when full gate openings are made.
Overfall Spillways
Commonly adopted for Earth dams.
Chute Spillways
Most suitable for narrow canyons.
Side Channel and Shaft Spillways
Usually used to provide approximately constant headwater flow under varying flow.
Siphon Spillways
Auxiliary spillway provided to take care of the possibility of having a flood geater than the spillway design flood.
Emergency Spillway
Used in farming to enable plants to grow when there is not enough rain, particularly in arid areas.
Irrigation-
the total required water for crop growth is not uniformly distributed over its entire life span.
Crop Period
the watering stops same time before harvest and the time duration from the first irrigation during sowing up to the last before harvest.
Base Period
sometimes, in the initial stages before the crop is sown, the land is very dry. In such cases, the soil is moistened with water as to helps in sowing the crops.
Paleo Irrigation
is used to describe the watering given to a crop when the plants are still young. It is usually the maximum single watering required, and other watering are done at usual intervals.
Kor watering
the total depth of water required to raise a crop over a unit area of land.
Delta
