Hydrology 1 Exam

Exam is on February 10th; ** look through book for conservation of mass and other physical laws of hydrology; Water's Properties, GHC, (fluxes and reservoirs residence time), Climate and the GHC, Precipitation, Evaporation and evapotranspiration (rates and mechanisms), infiltration, Chapters 1-4???

What makes the state of water unique?

It can take the form of a solid, liquid, or gas

Density of water

dependent on salinity, temperature, and pressure

Compressibility of water

Nearly incompressible

The dissolving ability of water?

Very high dissolving ability

Heat capacity of water

The highest of all liquids and solids EXCEPT NH3

Surface tension of water

highest of any liquid

heat conduction of water

highest of any liquid

the boiling and freezing temperatures of water

anomalously high

Describe Water’s Molecular Structure

H2O - two hydrogen and one oxygen; covalent bonding

Describe ionic bonding

elements of opposite ends of the periodic table generally form ionic bonds

tendency to lose/gain electrons

forms a neutral compound

generally weak bonds

transfer of electrons from donor to acceptor

describe covalent bonding

form between atoms with partially filled outer orbitals

sharing of valence electrons

VERY STRONG BONDS

The definition of HYDROLOGY

The geoscience that describes and predicts the occurrence, circulation, and distribution of the water of the earth and its atmosphere

What is the Global Hydrologic Cycle?

The distribution and spatial and temporal variations of water in the global water system

What is Heat?

the measure of how many molecules in body are vibrating and how rapidly they are vibrating

What is Temperature?

the measure of how rapidly the molecules in a body are vibrating

Describe sensible heat

associated with temperature change

Describe latent heat

associated with change in state

What is heat capacity?

the temperature response of a body to the addition or loss of heat

The role of heat in hydrogen bonds

Heat breaks the hydrogen bonds and causes molecules to move (increasing temperature)

What is Fick’s Law of Diffusion?

• describes the movement from high concentration to low concentration

• rate of movement is proportional to the concentration gradient

describe the Global Energy Budget

• a balance of inputs and outputs

• input of solar shortwave energy

• output of infrared and longwave (heat) radiation

Darcy’s Law (will not be applied to problems in exam 1)

determines how quickly water is flowing

What is the latitudinal effect on light penetration

• the higher the latitude, the higher the incident angle

• greater surface area affected

• greater volume of atmosphere

• more reflection

What are the factors affecting infiltration?

• water input rate

• surface ponding depth (potential for puddle formation)

• surface hydraulic conductivity

• saturation of surface pore spaces

• surface slope and roughness

• chemistry of soils

warm air is more or less dense than cold air

LESS DENSE

humid air is more or less dense than dry air

LESS DENSE

Warmer air can hold (more/less) water vapor than cold air

More water vapor

How is Coriolis force affected by latitude?

Coriolis force increases with latitude

The relationship between Coriolis force and velocity

No velocity = no Coriolis force

Describe the term “Monsoon”

Any seasonal reversing of wind direction

Summer monsoon causes

significant rainfall in most of Indian subcontinent and SE Asia

Winter Monsoon affects what?

Australia and SE Asia

What causes precipitation?

• cooling

• condensation

• droplet growth

• importation of water vapor

Describe Adiabatic Cooling!

as air pressure decreases on an air parcel, it expands, rises, and cools (without the addition or loss of heat)

What is dew point?

the temperature at which a parcel of air reaches saturation with respect to water vapor

Condensation is caused by…

the coalescence of water molecules

• a process catalyzed by cloud condensation nuclei

Droplet growth needs..

• high concentration of water droplets

• aid by presence of template catalysts

Which processes induce adiabatic cooling?

• convergence of air masses

• thermal convection

• orography

What is Orographic Uplift?

as an air mass rises above a mountain or landmass, it cools and expands;

What is Thermal Convection?

land mass is heated, air mass above land mass rises and cools at dry adiabatic rate, attains dew point, cools at wet adiabatic rate

(due to this instability, this is linked to thunderstorms)

ITCZ

• the intertropical convergence zone

• seasonal migration due to equatorial tilt and land/sea interactions

Define Interception

the segment of gross precipitation input that wets and adheres to aboveground objects until it is returned to the atmosphere through evaporation

Define Interception Loss

intercepted water that evaporates

Different types of interception loss?

• canopy interception loss

• litter interception loss

• total interception loss

The amount of water intercepted is a function of:

• rainfall intensity

• the species, age, and density of prevailing plants and trees

• the season of the year

Net rainfall can be described as

the loss via depression storage

• loss to evaporation

• infiltration to groundwater

Rate of Evaporation depends on:

• relative vapor pressure in air and at evaporative surface

• wind speed

• degree of turbulent mixing

What is required before liquid water can change to vapor?

The breaking of hydrogen bonds

The energy required to break hydrogen bonds is called???

Latent heat of vaporization

• equal and opposite to energy released during condensation

Define Transpiration

A physical process where water vapor escapes through open stoma (on the undersides of leaves)

Guard cells in plants are affected by:

• light intensity

• humidity

• water content of leaf cells

• leaf-air vapor pressure difference

• ambient CO2

Hydraulic zones in soils

• root zone

• vadose zone

• capillary fringe

• saturated (phreatic) zone

Subsurface Geology Factors In Hydrology

• porosity

• water content

• permeability

• hydraulic conductivity

• hydraulic pressure

What is Baseflow?

• records the groundwater contribution to surface water flow

• varies temporarily in response to precipitation, infiltration

The Rate of Evaporation is dependent on

• relative vapor pressure in the air

• wind speed

• degree of turbulent mixing

subsurface geology factors

• porosity

• water content

• permeability

• hydraulic conductivity

• hydraulic pressure

Types of stream gages

• staff gage

• wire weight gage

• open pipe gage

• gage house

What is gage height?

height of a stream surface relative to a reference datum

Why measure the gage height?

determines the volume of water moving in a stream

and determines the depth at which stream velocity is measured

What is stream discharge?

volume of water flowing through a stream channel

What is the fuel for streamflow?

Runoff

Runoff is the precipitation that remains

AFTER interception, infiltration, and depression storage

Overland flow

conveys water to stream channels

What are the streamflow components?

• baseflow

• interflow

• channel precipitation

• direct surface runoff

What is the purpose of a hydrograph?

it records the temporal and spatial integration of these contributors

Describe baseflow measurements

records the groundwater contribution to surface water flow;

varies temporarily in response to precipitation, infiltration