1. Rivers and Groundwater
Quick Review
Rivers and Groundwater
April 2001 Copyright by Dr. Isiorho

2. April 2001 Copyright by Dr. Isiorho
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

3. April 2001 Copyright by Dr. Isiorho
Earth’s Water
How much water is there? Approx 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 humans- groundwater
Glacier and Ice – largest amount of fresh water
April 2001 Copyright by Dr. Isiorho

4. 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, Ephemeral
April 2001 Copyright by Dr. Isiorho

5. April 2001 Copyright by Dr. Isiorho
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

6. April 2001 Copyright by Dr. Isiorho
*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

7. April 2001 Copyright by Dr. Isiorho
Stream Transport
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

8. April 2001 Copyright by Dr. Isiorho
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

9. April 2001 Copyright by Dr. Isiorho
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

10. April 2001 Copyright by Dr. Isiorho
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

11. April 2001 Copyright by Dr. Isiorho
Groundwater Movement
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 ( in/day). The slow movement stores the water making it available to humans.
April 2001 Copyright by Dr. Isiorho

12. 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

13. April 2001 Copyright by Dr. Isiorho
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

14. 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

15. Products of Groundwater
Karsts
Water reacts with carbon dioxide to form weak carbonic acid which then attacks limestone
H2O + CO2 => H2CO3 + CaCO3 => Ca++ HCO3 –
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

16. April 2001 Copyright by Dr. Isiorho
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