Quick Review
Rivers and Groundwater
April 2001 Copyright by Dr. Isiorho
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Surface Water

The Hydrologic Cycle
 Take a look at St. Joseph or Ste. Mary’s
river in Ft. Wayne and relate that to the
quotation below
 “All the rivers run into the sea, yet the sea is
not full. To the place from which the rivers
come, there they return” Ecle. 1:7
April 2001 Copyright by Dr. Isiorho
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Earth’s Water
How much water is there? Approx. 1.36 billion km3 (326
million mile 3) and this amount is fairly constant
 The continuous circulation of water through the ocean,
land and the atmosphere is the process called hydrologic
cycle
 Distribution of Earth’s water
 ~97 % in ocean; ~2.35% ice/glacier; ~0.65% Lakes,
Streams, Groundwater, Atmosphere
 The largest amount of fresh available to humansgroundwater
 Glacier and Ice – largest amount of fresh water

April 2001 Copyright by Dr. Isiorho
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Things you need to know about
Streams

A stream is a surface water flow confined to a channel
Floodplain- flat land immediately surrounding a stream which may
be submerged if a river overflows its bank


Drainage Basin- land areas that supply surface water to the river
Drainage Divide- topographic highland that separates two adjacent
drainage basins

Tributaries- streams that contribute water to main (trunk) stream
 Distributaries- main river splits into small channels
 Graded Stream- state of temporary equilibrium
 Base level- lowest point to which a river can erode
 Discharge- the amount of water that flows through a given area

(Q=V*A)
Types of Rivers- Effluent, Influent, Exotic, Perennials, Intermittent,
April 2001 Copyright by Dr. Isiorho
Ephemeral
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Stream Erosions

Graded Streams Aggregation- too much sediments
 Degradation- occurs when there is less sediments
 Gradient- know how to calculate this

Stream Erosion
 Abrasion
 Hydraulic lifting
 Dissolution
April 2001 Copyright by Dr. Isiorho
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*Drainage Patterns
Streams erode their networks of tributary valleys and distinctive
drainage patterns. A drainage pattern is a reflection of the underlying
rock material or structure.

Drainage Types (Patterns)
 Dendritic
 Radial
 Rectangular
 Trellis
 Annular
 Parallel
 Deranged


Stream Piracy
Channel patterns- straight, braided or meandering, oxbow
lake
April 2001 Copyright by Dr. Isiorho
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Stream Transport

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Velocity of sediment transport is controlled by its
discharge
Stream Capacity or carrying Capacity is the total volume
of sediments (load) it can carry and it is controlled by its
discharge
Competence- the maximum size of sediments (load) a
stream can carry and it is controlled by its velocity
Sediments are transported in the following format
 Suspended load
 Bed load
 Dissolved load
April 2001 Copyright by Dr. Isiorho
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Stream Deposition
Alluvium- sediment materials that settle from
water
 Point bar- sediments deposited within the channel
 Flood plain Deposits
 Levees
 Backswamp- deposits that make a flood plain’s wetland

Alluvial fans- formed where stream valley widens
 Delta- formed by the deposition of sediments in
standing water where the main stream breaks into
smaller channels
April 2001 Copyright by Dr. Isiorho
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Flood Control
Floods occur when water flow exceeds a river’s
channel capacity. The 1982 Flood in Ft. Wayne
 Management
 Forecast and Prediction

Flood Control Structures
 Levees and Flood walls

Alteration of Channels- channelization
 Flood way zone- structural development
restriction
April 2001 Copyright by Dr. Isiorho
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Groundwater

Types of groundwater– hygroscopic water (not available to
plants), capillary water, and gravity water.
 Porosity is the ratio of the voids to sediment (rock) volume
 The surface water will percolate downwards until it
reaches a zone where all the pore spaces are saturated with
water
 The line that separates the saturated from unsaturated zone
is the Water Table
 A geologic material that is porous, permeable, saturated
and will yield enough water when a well is drilled into it is
called an AQUIFER
April 2001 Copyright by Dr. Isiorho
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Groundwater Movement

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For groundwater to flow- need porous and permeable
materials
Porosity is the percent of pore spaces in relation to the total
soil/rock/sediment volume
Permeability is a measure of the ability of rock/sediment to
transmit fluid
Groundwater flow occurs when there is a hydraulic
gradient
Hydraulic conductivity is the ability to transmit
groundwater. Typical groundwater flow is slow ~0.5 – 1.5
cm/day (0.2 - 0.6 in/day). The slow movement stores the
water making it available to humans.
April 2001 Copyright by Dr. Isiorho
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



Tapping Groundwater
Reservoir
Groundwater depth is a reflection of local topography and
prevailing climate
Aquifers are permeable water-bearing bodies of geologic
materials
 Unconfined and Confined aquifers
Aquiclude and Aquitard
Artesian flow- water flows to the surface from wells
without pumping
 Potentiometric surface
 Natural Springs
 Geysers- intermittent surface emission of hot
water/steam
April 2001 Copyright by Dr. Isiorho
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Groundwater Pumping

Features Associated with Pumping
 Cone of depression- local depression in water around pumping
well
 Subsidence- compressed land due to aquifer depletion
 Salt water intrusion- due to over pumping along coast line



Greater demand for water- leads to groundwater depletion
and introduction of pollutant
Excessive withdrawal of groundwater from aquifer may
result in…land subsidence, change in groundwater flow
pattern, cause drawdown, depletion of aquifer
Solutions- enhance recharge, water transfer, conservation,
desalinization, and use of iceberg
April 2001 Copyright by Dr. Isiorho
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Groundwater
Contaminants/Purification

Natural occurring solutes- Chlorine, Arsenic, Mercury,
and Selenium

Manufacturing contaminants- from household
products:

cans of paint, solvent, cleanser etc.
Natural Groundwater Purification
 Filtration- adhere to clay particles
 Decomposition- some decompose completely by
oxidation
 Bacteria action- organic solids consumed by
microorganis
April 2001 Copyright by Dr. Isiorho
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Products of Groundwater

Karsts
 Water reacts with carbon dioxide to form weak carbonic
acid which then attacks limestone
++ HCO –
 H2O + CO2 => H2CO3 + CaCO3 => Ca
3
 Caves- natural underground cavities and most common
geological product of limestone dissolution
 Cave deposits- spelotherms are deposits on cave surfaces
in a variety of forms: travertine, Stalactite, Stalagmite,
banded draperies or drip curtains

Growth of spelotherm- depends on the solution and
porosity of surface material, climate, topography, and
vegetation
April 2001 Copyright by Dr. Isiorho
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Karsts Topography
Surface expression of the geology of dissolved limestone
and work of near surface water
 Cave and Karsts landscapes are extremely sensitive- so
need to be protected
 Landform
 Sinkholes-circular surface depression
 Disappearing Streams- flow through sinkholes may emerge as
spring several kilometers away
 Natural Bridge- series of neighboring sinkholes expand and join
together
April 2001 Copyright by Dr. Isiorho
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