CELE Hydraulics & Fluid Mechanics — Hydrology and Water SupplyConcept Map

Concept

The Hydrologic Cycle

Sub Concepts

• Precipitation
• Interception
• Infiltration
• Surface Runoff
• Streamflow
• Evaporation
• Transpiration
• Evapotranspiration

Relationship To Central

Foundation for understanding water movement in the environment and how precipitation becomes runoff

Concept

Runoff and Peak Discharge

Sub Concepts

• Rational Method (Q = CiA/360)
• Runoff Coefficient (C)
• Rainfall Intensity (i)
• Catchment Area (A)
• Time of Concentration (tc)
• Peak Discharge Calculation
• Design Storm Duration

Relationship To Central

Core quantification method for designing drainage and conveyance systems

Concept

Rainfall Intensity-Duration-Frequency (IDF)

Sub Concepts

• IDF Curves
• Return Period (T)
• Design Duration
• Intensity Variation
• Frequency Analysis
• Local Rainfall Data

Relationship To Central

Provides design rainfall data tied to return periods and local climate

Concept

Runoff Volume

Sub Concepts

• Volume Calculation (V = CPA)
• Precipitation Depth (P)
• Runoff Coefficient (C)
• Catchment Area (A)
• Unit Conversions
• Cumulative Yield

Relationship To Central

Quantifies total water yield from a storm for storage and conservation planning

Concept

Water Supply Fundamentals

Sub Concepts

• Population and Per-Capita Consumption
• Average Daily Demand
• Maximum Day Demand
• Peak Hour Demand
• Demand Factors
• Storage Requirements

Relationship To Central

Demand estimation and source selection for safe and reliable supply

Concept

Water Supply Sources

Sub Concepts

• Surface Water Sources
• Reservoirs
• Rivers and Streams
• Groundwater Sources
• Wells
• Spring Sources
• Rainwater Harvesting

Relationship To Central

Selection and sizing of intake and storage facilities

Concept

Well Hydraulics

Sub Concepts

• Well Yield
• Drawdown
• Aquifer Properties
• Specific Capacity
• Pump Selection
• Well Spacing

Relationship To Central

Design and operation of groundwater extraction systems

Concept

Reservoir Analysis and Sizing

Sub Concepts

• Mass Balance
• Inflow vs Demand
• Seasonal Variation
• Draft and Yield
• Capacity Curves
• Reliability Analysis

Relationship To Central

Determination of storage volume to meet annual demand and variability

Concept

Unit Conversions and Practical Calculations

Sub Concepts

• mm/hr to m³/s conversion
• Hectares to m² conversion
• mm depth to m³ volume
• L/day to m³/s conversion
• Per-capita demand scaling

Relationship To Central

Critical for correct application of SI-based rational method in field practice

Concept

Common Board-Exam Errors and Pitfalls

Sub Concepts

• The 360 conversion factor
• Duration-intensity relationship
• Unit inconsistencies
• Peak vs average demand confusion
• Runoff coefficient misapplication

Relationship To Central

Awareness of frequent mistakes ensures accurate licensure-exam performance

To

Runoff and Peak Discharge

From

The Hydrologic Cycle

Strength

strong

Relationship

The hydrologic cycle defines how precipitation becomes runoff; the rational method quantifies peak discharge from that runoff

To

Rainfall Intensity-Duration-Frequency (IDF)

From

Runoff and Peak Discharge

Strength

strong

Relationship

The rational method requires design rainfall intensity from IDF curves, selected at the time of concentration

To

Runoff Volume

From

Runoff and Peak Discharge

Strength

strong

Relationship

Both use the runoff coefficient C and catchment area A; peak discharge is instantaneous rate, volume is cumulative over storm duration

To

Water Supply Sources

From

Water Supply Fundamentals

Strength

strong

Relationship

Estimated demand determines the capacity and type of source infrastructure needed

To

Well Hydraulics

From

Water Supply Sources

Strength

moderate

Relationship

For groundwater sources, well equations predict yield and drawdown under pumping

To

Reservoir Analysis and Sizing

From

Water Supply Sources

Strength

moderate

Relationship

For surface sources, mass-balance analysis determines required storage volume to meet variable demand

To

Runoff Volume

From

Rainfall Intensity-Duration-Frequency (IDF)

Strength

moderate

Relationship

IDF data provides the precipitation depth P used in the runoff-volume formula V = CPA

To

Runoff and Peak Discharge

From

Runoff Coefficient

Strength

strong

Relationship

C is a critical parameter in Q = CiA/360, varying from 0.1 (lawns) to 0.95 (pavement)

To

Rainfall Intensity-Duration-Frequency (IDF)

From

Time of Concentration

Strength

strong

Relationship

Design duration in IDF lookup equals time of concentration; correct pairing ensures proper intensity selection

To

Runoff and Peak Discharge

From

Unit Conversions and Practical Calculations

Strength

strong

Relationship

The 360 conversion factor is essential when using Q = CiA/360 with intensity in mm/hr and area in hectares

To

Runoff Volume

From

Unit Conversions and Practical Calculations

Strength

strong

Relationship

Correct unit consistency is critical: mm depth + ha area gives m³; m depth + m² area also gives m³

To

Unit Conversions and Practical Calculations

From

Water Supply Fundamentals

Strength

moderate

Relationship

Per-capita demand (L/person/day) must be scaled to population and converted to m³/day for system sizing

To

Runoff and Peak Discharge

From

Common Board-Exam Errors and Pitfalls

Strength

moderate

Relationship

Awareness of the 360 factor, intensity-duration pairing, and peak vs. average demand prevents frequent calculation errors

To

Water Supply Fundamentals

From

Common Board-Exam Errors and Pitfalls

Strength

moderate

Relationship

Understanding the distinction between average, max-day, and peak-hour demand is critical for correct system design and exam success

To

Runoff and Peak Discharge

From

Catchment Area

Strength

strong

Relationship

Area A is a direct input to Q = CiA/360; errors in area unit conversion lead to incorrect discharge

To

Water Supply Fundamentals

From

Demand Factors

Strength

strong

Relationship

Multipliers (1.5× for max-day, 2–3× for peak-hour) transform average demand into design-point demand

To

Well Hydraulics

From

Well Yield

Strength

strong

Relationship

Yield is the sustainable pumping rate; determined by aquifer properties, well design, and drawdown limits

To

Reservoir Analysis and Sizing

From

Mass Balance

Strength

strong

Relationship

Inflow (from hydrologic analysis) versus demand (from consumption) determines required storage capacity

To

Runoff Volume

From

Precipitation Depth

Strength

strong

Relationship

Rainfall depth P from IDF or observed storms is multiplied by C and A to compute total runoff volume

To

Water Supply Fundamentals

From

Per-Capita Consumption

Strength

strong

Relationship

Population × per-capita consumption (L/person/day) is the foundation for all demand estimates