CE 116 Finals

Watershed Demands

Fishery, Farming, Tourism, Water Supply, Hydropower, Biodiversity

Water Stressors

Rapid population growth, Domestic/Agri/Industrial Waste Disposals, Watershed Degradation, Climate Change,

Water Stress

low per capita availability due to increasing population demands

Countries vulnerable to water stress

Consumptions exceeds more than 20% available renewable supply

Dublin Principles

Freshwater is a finite and vulnerable resource, Woman play a central role in the provision (etc) of water, Water has economic value, Water development and management should be on a participatory approach

Challenges to WRS

Urbanization, Droughts, Climate Change, Flooding, Human Induced Factors

Major Impacts of Increased Runoff

Increased Streamflow, Decline in runoff quality, Higher Runoff with higher pollutant, Diminished GW recharge, Flooding, Sewer overflow, Damage to stream and Aquatic Life, Destyoed habitats

Factors affecting Urban Flood Management

No Planning Development, High Population concentration, Lack of storm and sewage water facilities, Polluted air and water, Difficulty of water supply against population, Bad public transpo

Why are hydraulic components importart?

Planning, Flood Risk reduction, Design, Environmental Impact, Restoration

Benefits of Dams

Cheap electricity, Flood Control, Year-round water source, Recreation and fishing in reservoir

Disadvantages of Dams

Large water loss via evaporation, fish movement disrupted, Reservoir displaces upstream land and peiple, Downstream estuaries deprived of silt

Groundwater Benefits

Cheap to extract, Little water loss via evaporation, Reliable water to extract

Disadvantages of groundwater

Lower Water table, Depletion, Subsidence, Saltwater Intrusion, Chem Contamination, Reduced Streamflow

Percentage of Agriculture usage

70%

Percentage of Industrial Use

22%

Percentage of Domestic Use

8%

Industrialized Countries

Use more water for industrial use

Food source consuming the most water

Meat

Percentage of Water from leaks

2/3

Effects of Reformed Water Levels

Higher Water Prices, Encourage Conservation, Incentives for Conservation, Penalties for Polluters

Percentage of Irrigation water NOT reaching crops

60%

More efficient Irrigation methods

Center Pivot Sprinklers, Time-controlled Irrigation, Soil Moisture detectors, Drip Irrigation

Purposes of Water Distribution Network

Supply system users with amount of water, Supply with adequate pressure at various loading conditions

Components of WDS

Pumping System, Distribution Storage, Distribution Piping

Main Distribution Links

Pipe Sections

Nodes

Either end of the pipe

Control Valves

Regulate flow/pressure

Pressure-Regulating Valve

Most common type of control valve

Isolation Valves

shuts down a section of the WDS

Distribution System Storage

Needed to equalize pump discharge

One advantage of the Hazen-Williams equation

C is not a function of the Reynold's number but only viable for water

Kinds of Pipe Networks

Series, Parallel, Branching

Equivalent Pipes

Simplification of a pipe network

Hydraulic Transients/Water Hammer

Occurs when water changes from one steady-state flow to another steady-state flow

Water Hammers can Cause

Rupture, Pipe Collapse, Vibrations, Pipe Displacements, Vapor Cavity

Causes of Water Hammers

Opening Closing of Valves, Flow Demand Changes, Controlled Pump Shutdown, Pump Failure, Pump start-up, Air-venting, Failure of flow on pressure regulation, Rupture

Ep (pipe modulus of elasticity)

incremental stress over increment deformation

Methods to control transients

Pump-control valves, Air chambers, Surge tanks, Valves, High-pressure-rated equipment

Embankment/Broad-fill Conditions

portion of the weight of teh adjacent prisms of fill transferred to central prism by shear

Forces at Bends and Changes in Cross-section

change in direction or magnitude of velocity causes change in momentum

Temperature Stress

causes by large changes in temps

Pump head-characteristic Curve

Graphical representation of the total dynamic head vs discharge pump can supply

Single Main Distribution

One main serves both street sides

410 kPa

recommended fire pressure

Price Elasticity of Demand

Willingness of consumers to give up water due to rising prices

Factors that influence water demand

Climate, Source Substitution, Water using equipment, Water supply system, Demographics and Land Use

Factors on Water Availability and Use

Water quantity and quality, Water Demands, Water Law, Regulations, Economic Factors, Water Works Infra

Allocations for east and west zones

40% for east, 60% for west

Pump

adds energy to a fluid, increasing pressure

Turbine

Extracts energy from water

Three Basic Elements for Power Generation

Means to create Head, Conduit to convey Water, Power Plant

Draft Tubes

convey water from discharge side to tailrace

Tailrace

maintains minimum tailwater elevation below power plant and keeps draft tube submerged

Forebay

Regulating reservoir that store water

Forebay facilitates

Low approach velocity to intake, surge reduction, sediment removal, storage

Impulse Turbine/Tangential Water-wheel/Pelton Wheel

free jet of water impinges on tge revolving element

Reaction Turbine/Francis Turbines

flow takes place in closed chamber

Fixed-blade Propeller Turbines

Water passes propeller axially

Kapalan Turbines

adjustable pitch blades

Tubular Turbines

guide vane assembly in line

Bulb turbines

Horizontal axial flow

Cavitation in turbines \___

causes pitting, mechanical vibration, loss of efficiency

Cavitation Index

Susceptibility to cavitation

True or False: susceptibility to cavitation changes with speed of impeller

true, greater speed means greater relative velocities

Trend of Hydraulic Turbine design is towards \___

Higher specific speed and smaller machines for the same design requirements and output

True or False: two turbines of identical geometric shape but of differing size will have the same efficiency

True, if phi values are the same

Positive-displacement Machines

Closed volume to squeeze or suck fluid (heart)

Dynamic (centrifugal Machines)

No closed volumes, rotating blades extract energy

Fans

low pressure gradient, high volume flow

Blower

Medium pressure gradient and flow rate

Compressor

High pressure gradient but low volume flow rate

3 Types of Dynamic Pumps

Radial, Axial, Mixed-Flow

Dynamic Pumps have the following types\____

Centrifugal, Mixed-Flow, Axial

Multistage Pumps

Have more than one impeller stage

Total Dynamic Head

Head against which a pump must operate

Cavitation

when absolute pressure at pump inlet decreases below vapor pressure of fluid

Net Positive Suction Head

absolute dynamic head

Pump Head-characteristic Head

Total dynamic head vs discharge pump can supply

Shutoff Head

head output at zero discharge

Normal Discharge/Rated Capacity

Q or H where pump is operating at most efficient

For pumps in parallel, curves are added\___

horizontally

For pumps in series, curves are added\___

vertically

Economic Justification

comparing plant with equivalent plant using other resources

True or False: HEP can stand alone

False

Load for the peak day of the year\___

determines required generating capacity

Load Factor

ratio of average load to peak load

Higher load factors means prices \____

are cheaper

Gross Head

total difference in elevation between water surface in the stream at diversion and water surface in stream

Net or Effective Head

head available for energy production after losses

Hydraulic Efficiency

ratio of net head to gross head

Capacity

maximum power which can be developed at normal head with full flow

Firm Power

100% expected power delivery

Design Head

head at maximum efficiency

Rated Head

head at which rated power is obtained when the wicker gates are fully open

Rated Discharge

Discharge when wicket gates fully open

Power rule curve

Defined as a curve or family of curves how a reservoir is to be operated under specific conditions

Which Island Group has highest System Capacity?

Luzon

Highest Plant Type portion in Luzon

Coal

Highest Plant Type Portion in Visayas

Geothermal

Highest Plant Type Portion in Mindanao

Hydro