Hydrology Final Exam

ABAC Dr.Ray

Properties of water

cohesion, adhesion, and capillarity

Cohesion

affinity of water itself

adhesion

affinity of water for other materials/surfaces

Capillary Action

phenomenon by which liquid rises in a narrow space involving surface tension, cohesion, and adhesion

Layers of the atmosphere (in order)

exosphere, thermosphere, mesosphere, stratosphere, troposphere

Primary chemicals (in order)

nitrogen, oxygen, trace chemicals

Lithosphere

the Earth’s crust

Hydrosphere

consists of water in all forms

What does the hydrosphere encompass?

atmosphere and lithosphere

Biosphere

global sum of all ecosystems, integrating all living beings and their relationships

law of conservation of mass

matter cannot be created or destroyed

Steps of the water cycle

Evaporation, transpiration, condensation, precipitation

Sublimation

evaporation from snow and ice

Evapotranspiration

transpiration and evaporation from all water, soils, snow, ice, vegetation, and other surfaces

Carbon cycle process

carbon dioxide fixation from primary producers, turned into carbs, consumer organisms, respiration or decomposer organisms

Nitrogen cycle

nitrogen fixing bacteria, nitrifying bacteria, denitrifying bacteria, biological fixation

Different spheres

atmosphere, lithosphere, hydrosphere, biosphere

different cycles

water, carbon, nitrogen, phosphorus, methane

What cycle encircles all the cycles?

biogeochemical

Determinants of water discharge to streams

precipitation, infiltration, evaporation, transpiration, storage, human uses

HU

hydrologic units

Hydrologic units

Region, subregion, basin, subbasin, watershed, subwatershed

interception

precipitation captured by the forest canopy

Throughfall

when precipitation exceeds interception

stemflow

precipitation running down branches and main stem

evapotranspiration

composite term for the ‘loss’ of water vapor from intercepting surfaces and leaf stomata

How do you measure watershed discharge?

weir or flume

How are forests advantageous to hydrology?

regulate precipitation, reduce flooding, reduce erosion, filter pollutants, recharge groundwater

Q

discharge

annual runoff =

precipitation - evapotranspiration

evapotranspiration =

transpiration + interception evaporation

Determinants for infiltration rates in forests

O horizon layer thickness, soil texture, soil organic matter, soil moisture, compaction

Interception rate for hardwood forests

10-15%

Interception rate for conifer forests

15-25%

Riparian

area/zone adjacent to stream

Riparian functions

sediment and nutrient filtering, stream bank stabilization, wildlife habitat and corridors, wood and OM supply, stream temp, biodiversity

Geomorphology

study of physical features of the surface of the Earth and their relation to its geological structures; the study of the origin and evolution of topographic and bathymetric features generated by different processes at or near Earth’s surface

Dominant weathering processes

glacial, aeolian, fluvial

creep

slow process of soil movement downslope

landslides

rapid process, triggered by events like earthquakes

Different sediment transports

suspension, traction, solution, saltation

fluvial

of or pertaining to rivers

perennial

sustains year-round flow

intermittent

sustains flow for at least 1-mo/yr

ephemeral

flow absent most of the time

reach

section of stream/river with similar hydrologic conditions

Tributary

small channels that discharge into a main stem

Alluvium

sediment deposited by rivers in floodplain or deltas

Characteristics of upper course of river continuum

steep, v-shaped valley, narrow, shallow channel, high bedload

Features of upper course of river continuum

interlocking spurs, waterfalls, gorges, v-shaped channel

characteristics of middle course of river continuum

open, gentle sloping valley with floodplains, wider, deeper channel, more suspended sediment

features of middle course of river continuum

meanders, river cliffs, slip off slopes, u-shaped channel

characteristics of lower course of river continuum

open, gentle sloping valley with floodplains, fast and wide floodplain, wide open valley, deep channel

features of lower course of river continuum

ox-bow lakes, flood plains, levees, flat-shaped channel

sinuosity

degree of meandering

Thalweg

line drawn to join the lowest points along the length of a stream bed

Factors that Increase the Risk of Flash Floods

prolonged rainfall, impermeable, steep-sided valley, flat flood plain, deforestation, urbanization

Drainage Drivers

topography/gravity, soil texture, impermeably layers, antecedent conditions

Hortonian Overland Flow

tendency of water to flow horizontally across land surfaces when rainfall has exceeded infiltration capacity and depression storage capacity

Rills

water moving over ground in small channels

sheetflow

water moving over ground across the whole surface

Saturated Overland Flow

the soil is completely saturated causing runoff

variable source area

the area that is saturated and involved in SOF changes over time during a precipitation event

Wetland Delineation

hydrology, vegetation, soils

Classification of Wetlands (EPA)

marshes, swamps, bogs, fens

EPA

US Environmental Protection Agency

Classification of Wetlands (FWS)

marine, estuarine, lacustrine, palustrine, riverine

FWS

US Fish and Wildlife Service

National Wetlands Inventory (FWS)

landscape position, vegetation cover, hydrologic regime

Classification of Wetlands (The Corps)

riverine, slope, depressional, flat, fringe

The Corps

US Army Corps of Engineers

The Corps Identification method

precipitation, groundwater, surface water

Marshes

frequently or continually inundated, emergent soft-stemmed vegetation, prairie potholes, fresh or salt, neutral pH

What are the most prevalent and widely spread wetlands in North America?

non-tidal marshes

Tidal Marshes

buffer ocean storms, slow shoreline erosion and absorb excess nutrients

Swamps

woody plants, saturated soil during the growing season, floodplain forests, often drained and cleared for agriculture

2 types of swamps

forested swamps, shrub swamps

bogs

peat deposits, acidic waters, precipitation fed, low in nutrients, prevents flooding by absorbing precipitation

2 ways a bog forms

terretorialization, paludification

terrestrialization

sphagnum moss growing over a lake or pond and slowly fills it

Paludification

sphagnum moss blankets dry land and prevent water from leaving the surface

pocosin

southeast bog, evergreen shrub and tree dominated, peak abundance in NC, no standing water present, ombrotrophic

Northern Bogs

low temps and short growing seasons, form in old glacial lakes

acidophiles

flora and fauna that can grow and survive in acidic conditions

Fens

peat-forming wetlands, receive water through drainage and groundwater, higher nutrient levels, low temperature and short growing seasons, reduce floods

How does a fen turn into a bog?

peat builds up and separate the fen from its groundwater supply

Ombrotrophic

rain provides most of the water

Wetland Determinants

hydrology, soils, vegetation

autotrophic microbes

reduces iron and magnesium using electron in ATP

Heterotrophic microbes

oxidize OM using iron and magnesium as electron acceptors

Arenchyma

oxygen-transporting structures/tissues in stems and roots

Adaptations of Wetland Plants

protective barriers against excessive saline, prolonged seed viability, seed germination under low oxygen conditions, production of buoyant propagules

OBL

obligate wetland

FACW

facultative wetland

FAC

facultative

FACU

facultative upland

UPL

obligate upland

Indicators for Hydro Veg

1) Rapid Test 2) Dominance test 3) Prevalence Index

CWA

Clean Water Act

Role and Responsibilities of U.S. Army Corps of Engineers

day-to-day program, permit decisions, conducts or verifies jurisdictional determinations, develops policy and guidance, enforces Section 404 permit provisions