midtems

Question 1

This type of precipitation happens in varying intensities. The areal extent of ____________________ is small in the range of less than 10km in diameter.

Answer 1

Convective Precipitation

Question 2

It occurs when warm, moist air is drawn into a low-pressure cold front. The warm air rises as it is drawn into the low-pressure zone and is subjected to adiabatic cooling.

Answer 2

Cyclonic Precipitation

Question 3

Precipitation which is caused by hills or mountain ranges deflecting the moisture-laden air masses upward, causing them to cool and precipitate their moisture.

Answer 3

Orographic Precipitation

Question 4

This term is used generally when the water droplets are of size 0.5-6 mm.

Answer 4

Rain

Question 5

It consists of ice crystals which is combined form of ice flakes. Initially these flakes
have density in the range of 0.06-0.15 g/cc (avg of 0.1 g/cc).

Answer 5

Snowfall

Question 6

When water droplets are of size lesser than 0.5 mm. Its intensity should be less than 1 mm/hr. In this case, particles are of such range that they can be seen floating into the air.

Answer 6

Drizzle

Question 7

When rain or drizzle comes in contact with cold ground at around 0°C, the water is
converted into ice coating termed as _______.

Answer 7

Glaze

Question 8

It is frozen rain drop which is formed when rain falls through air at sub-atmospheric
temperature or sub-freezing temperature.

Answer 8

Sleet

Question 9

consisting of balls or lumps of ice, called hailstones, that form during thunderstorms.
size > 8 mm

Answer 9

Hail

Question 10

-Total rainfall over a specific area
- Rain gauges (in mm)

Answer 10

Rainfall Depth

Question 11

-Length of time rainfall occurs
- Start to end of rainfall event

Answer 11

Rainfall Duration

Question 12

rate of rainfall (mm/hr)

Answer 12

Rainfall Intensity

Question 13

a graphical representation of rainfall intensity over time

Answer 13

HYETOGRAPH

Question 14

refers to the quantification of precipitation at a specific
location using instruments like rain gauges. This method captures the amount of rain that falls over a fixed area, providing data that can be used for hydrological studies, weather forecasting,
and agricultural planning.

Answer 14

Point rainfall measurement

Question 15

Example of Point Rainfall Measurement Instruments:

Answer 15

1. Standard Rain Gauge
2. Tipping Bucket Rain Gauge
3. Weighing Rain Gauge

Question 16

is an instrument used to measure the amount of precipitation, typically rain,
over a specific period. It usually consists of a cylindrical container with a funnel at the top that directs rainwater into a graduated measuring tube. The amount of water collected in the tube is then measured, usually in millimeters or inches, to determine the total rainfall.

Answer 16

rain gauge

Question 17

Design: A simple cylindrical container with a funnel leading to a graduated measuring tube.

Usage: Measures the total rainfall over a period. The user manually checks and records the measurement.

Answer 17

Standard Rain Gauge (Non-Recording Rain Gauge)

Question 18

Design: Contains a small bucket that tips and empties when it fills with a predetermined amount of water (often 0.2 mm or 0.01 inch). Each tip is recorded electronically.

Usage: Provides continuous, real-time measurements of rainfall, making it useful for automatic weather stations.

Advantages: Records both the amount and intensity of rainfall.

Answer 18

Tipping Bucket Rain Gauge

Question 19

Design: Collects rain in a container placed on a scale. The weight of the water is measured and converted into a depth of rainfall.

Usage: Used in environments where snow or ice might accumulate, as it can weigh precipitation
in all forms.

Advantages: Highly accurate and can measure all types of precipitation (rain, snow, sleet).

Answer 19

Weighing Rain Gauge

Question 20

Design: Uses laser or infrared beams to detect raindrops as they pass through a sensing area.

Usage: Commonly used in automated weather stations and aviation, where precise, real-time data is essential.

Advantages: Can measure the size and velocity of raindrops, which helps in calculating rainfall intensity.

Answer 20

Optical Rain Gauge

Question 21

Design: Measures the sound of raindrops hitting a surface, typically used underwater to detect rainfall on the water’s surface.

Usage: Used in marine environments to monitor rainfall over oceans and large bodies of water.

Advantages: Can measure rain over a large area without direct contact.

Answer 21

Acoustic Rain Gauge

Question 22

Design: Rainwater is collected in a large container with a float inside. The rise of the float
indicates the amount of rainfall, which is then recorded.

Usage: Used in hydrological studies, particularly in areas prone to heavy rainfall.

Advantages: Can handle large volumes of water, making it suitable for areas with intense
rainfall.

Answer 22

Float-Type Rain Gauge

Question 23

refers to the amount of rainfall measured at a specific location, typically using a rain gauge.

Answer 23

Point rainfall

Question 24

This method involves taking the simple average of rainfall measurements from multiple
points within the area of interest.

Answer 24

Arithmetic Average

Question 25

This method assigns weights to each rain gauge based on the area it represent

Answer 25

Thiessen Polygon Method

Question 26

This method involves drawing contour lines (isohyets) of equal rainfall on a map. The area between these lines is then used to calculate the average rainfall.

Answer 26

Isohyetal Method

Question 27

Converting point rainfall to aerial rainfall is crucial for designing and managing water resources projects, such as dams, drainage systems, and flood control measures.

Answer 27

Areal Reduction Factors (ARF)

Question 28

Is a graphical method used to check the consistency of precipitation data over time.

Answer 28

DOUBLE MASS ANALYSIS

Question 29

is the process where water on the ground surface enters the soil. It happens naturally when rain, irrigation, or any water source moves through the soil, filling gaps and spaces between particles.

Answer 29

Infiltration

Question 30

Essential for sustaining water supplies and ecosystems, especially during dry periods.

Answer 30

Groundwater Recharge

Question 31

Helps prevent flooding and erosion by reducing the volume of water that flows over land.

Answer 31

Reduction of Surface Runoff

Question 32

Improves water quality by filtering contaminants as water moves through the soil.

Answer 32

Pollutant Filtration

Question 33

Factors affecting infiltration

Answer 33

Precipitation Level, Soil Characteristics, Vegetative Cover, Slope of the Land, Soil Saturation, Evapotranspiration Level, Human Activities

Question 34

can either increase or decrease infiltration.

Answer 34

Vegetative cover

Question 35

refer to the assessment of how much water seeps into the soil from precipitation, irrigation, or other sources.

Answer 35

Infiltration Measurements

Question 36

is a simple instrument that is used to determine the rate of infiltration of water into the soil. The rate of infiltration is determined as the amount of water per surface area and time unit, that penetrates the soil.

Answer 36

Double Ring Infiltrometer

Question 36

a ring is driven into the ground and water is either continuously supplied or provided at a falling head condition.

Answer 36

Single Ring Infiltrometer

Question 37

which apply water over a circular portion of the soil surface and measure the flow rate of water drawn into the soil, are widely used instruments for measuring the hydraulic conductivity of soil in the field.

Answer 37

Tension Infiltrometers

Question 38

The ______________ is a significant empirical framework in hydrology, developed by Robert E. Horton in the early 1930s. It describes how the infiltration capacity of soil decreases over time during a rainfall event.

Answer 38

Horton Model

Question 39

the model is not directly linked to measurable physical properties of the soil

Answer 39

Parameter Measurement

Question 40

best suited for short-duration, high-intensity rainfall events and may not perform well under continuous or prolonged rainfall conditions

Answer 40

Limited Applicability

Question 41

provides a reliable method for estimating how quickly water can infiltrate into soil

Answer 41

Estimation of Infiltration Rates

Question 42

model captures the decrease in infiltration capacity over time

Answer 42

Dynamic Modeling

Question 43

aids in designing effective stormwater management systems

Answer 43

Applications in Urban Planning

Question 44

Horton's work has laid the groundwork for subsequent advancements

Answer 44

Foundation for Further Research

Question 45

The __________________________ is used to describe water infiltration into soils. It was developed by J.R. Philip in 1957 and is commonly applied to model unsteady infiltration of water into soil.

Answer 45

Philip’s Equation (or Philip's infiltration equation)

Question 46

The ______________________is an approximate model utilizing Darcy’s law. The model is developed with the assumption that water is ponded on the ground surface. Consider a vertical column of soil of unit horizontal cross-sectional area and let a control volume be defined around the wet soil between the surface and depth L.

Answer 46

Green-Ampt model

Question 47

The Green-Ampt model was developed by ____________ and ______________ in the early 1900s, estimates downward infiltration when water ponds on the soil surface. It builds on earlier research in soil physics, particularly Edgar Buckingham's work on unsaturated soil flow.

Answer 47

Heber Green & G.A. Ampt

Question 48

helps explain why infiltration rates decrease over time, as the hydraulic gradient driving infiltration diminishes. Despite its assumptions, it remains a valuable tool for understanding and predicting infiltration dynamics.

Answer 48

The Green-Ampt model

Question 49

___________ in hydrology refers to the period during which water accumulates on the surface of the ground or in depressions, such as ponds or fields, before it begins to infiltrate into the soil or runoff into nearby water bodies. It is a key factor in surface water dynamics, especially in areas with low infiltration rates or impervious surfaces, such as urban settings.

Answer 49

Ponding time

Question 50

is the time interval between the onset of rainfall and when water starts to pool or accumulate on the ground surface due to the ground’s inability to absorb all the rainfall immediately.

Answer 50

Ponding time