1993

floodwalls act as a bottleneck for rising waters

STL

surface layer of water

moves down steepest slope

erodes substrate

creates rill channels

rills coalesce, deepen, and downcut into channels[image]

Drainage Network

Catchments

Watersheds

Bed Load (10%)

Suspended Load (90%)

Dissolved Load

Measuring maximum size of the sediments transported

by river

The amt of water flowing in a channel

volume of water passing a point per unit of time

=water velocity * channel width * channel depth

cubic feet per second

cubic meters per second

Q=W x D x V

Stream Velocity

Longitudinal Profile of a River

Towards the mouth (end)

Gradient flattens

Discharge increases

Grain sizes smaller

Channels describe broad meander belts

lowest point to which a stream can erode

streams cannot erode below sea level

lake serves as a local (or temp) base lvl

Abrasion

River Erosion

sediment grains in flow sandblast rocks

-bedrock exposed in channels polished smooth

-potholes

Dissolution

River Erosion

Scouring

River Erosion

Breaking and Lifting

River Erosion

River Erosion Location

Downcutting

River Erosion Location

Lateral

River Erosion Location

Headward Erosion

Deposition on inside

erosion on outside[image]

River Sediment Deposition Features

Natural River Levees

River Sediment Deposition Features

Point Bar Deposits

River Sediment Deposition Features

Island Bars/Braided Streams

River Sediment Deposition Features

Alluvial Fan

build at base of mtn front

sediment rapidly dropped near stream source- carried to mouth

River Sediment Deposition Features

Deltas

stream enters standing water

sediment drops out

Effects of Land Use Changes

Forest-> farmland

increases soil eroision

stream deposition

gradient & velocity

river channel erosion

increases impervious cover

 inc. lower magnitude flood frequency

reduces lag time of flooding

Flooding

Stage

Flooding

Hydrograph

Flooding

Recurrance Interval

R= (N+1)/M

N= number of years of record

M= rank of individual flow within the recorded years

Types of Flooding

Upstream Flood

land use changes

frequency and magnitude

lag time and duration

sediment load

effectiveness of forecasting

runoff has effects on sediment transport and surface erosion

geologic factors (type and structure of soils and rocks)

topographic factors (relief and slope gradient)

climatic factors (type, intensity, duration, dist)

vegetation factors (type, size, dist)

land use practice factors

The Water Table

Vadose

unsaturated zone

moisture sticks to grain surfaces

air pockets remain

saturated zone

all pore space filled

not flat

mimics land surface- high where land is high, low where land is low.

mimic artesian aquifers

elevation creates artificial potentiometric surface

pressure drives water through the distribution system

originally formed with the material 

vesicles in basalt

May decrease with:

burial compaction

cementation

Crystalline rocks have very little primary porosity

develops later

fracturing

faulting

dissolution

flows slowly under the influence of gravity

in unsaturated zone, it is straight downward

in saturated zone, it's governed by gravity and pressure

Ocean current=3km/hr

Steep river channel=30km/hr

Groundwater=.00002 km/hr

develop when groundwater dissolves limestone

GW is weakly acidic (CO2)

-formed from precipitation of dripstone

-develop when GW entering a cave degasses CO2

-CaCO3 is precipitated from this water on interior surfaces 

-over time CaCO3 coatings grow into stalagmites, tites, and columns

removal or diversion from its SW or GW sources temporarily, e.g. irrigation, thermoelectric, industrial use

hardness

dissolved iron, manganese, and hydrogen sulfide gas

dissolved arsenic

dissolution of carbonates add Ca2+ and Mg2+

reduce the effectiveness of soap

mitigated by ion exchange

dissolved and pure organic and inorganic compounds

dissolved metals

pathogenic microbes

pump and treat

volatilize and vaporize

steam clean

bioremediation utilizes bacteria to clean groundwater

Dead organic matter decomposed by bacteria, an oxygen demanding process

Biochemical Oxygen Demand (BOD): high BOD assoc with a high level of decaying org material in h20, reducing dissolved O for other healthy organisms

Sources of oxygen demanding waste: natural processes, ag applications, urban sewage, and runoff

Cultural eutrophication- algae bloom, triggering BOD production

Fertilizer, feedlots, and discharge from wastewater treatment plants

-temp increases

-hot water discharge from industrial operations, power plants, abnormal ocean, currents, urban runoff

Discrete, confined, and readily identifiable

Sources: landfills, discharge from industries, power plants, storm water runoff, etc...

-diffused, intermittent and hard to specifically identif

-causes often regional, compound, and cumulative

-Influenced by land use, climate, hydrology, topography and geology

-Common sources: urban runoff, ag, mining

Secondary Maximum Contaminant Levels

-color/odor