Chapter 15,17,18

G’ water Replinishment by infiltrated rain. Rainfall infiltrates downward to aquifer. Similar to drainage basins. May come from miles away beneath several surface watersheds for deeper ones. Wells are drilled into the zone of saturation, i.e., the aquifer. This may be a sand or gravel bed or perhaps a fracture zone in a crystalline (igneous or metamorphic) or sedimentary rock, or even saprolite, in some cases.
Hydritic Soil
Develops with long term water saturation. Soils in which the upper 12 inches is water saturated for more than 1/8th of the growing season.
High Velocity rough bottom
causes of turbulent stream flow. Mountain stream- high gradient down stream. 1.High energy 2. High oxygen 3. Low temp = low biodiversity.
Dendritic steam pattern
random treelike stream system
Stream Gradient
elevation change per unit distance (feet/mile) related to local topography & largely determines speed velocity. Limit to downward erosion. When base level rises upstream the gradient decreases= deposits sediment load. When base level drops downcutting occurs.
Meanders, natural levees, cutoffs
characteristics of low gradient rivers. Found in locations with low gradients with wide flood plains. Low gradient rivers.
flowing water eco systems. examples: Creeks, rivers
Wetland Hydrology
Can occur in upland areas with clay rich soils (like gpc campus).poorly drained, with retained sulfur and methane.Can occur on flood plains, hilltops on rare occasions when excessive clay will not allow drainage. On floodplain a wetland may not be next to a creek or river.
Roundness of stream pebbles
Is related to stream transport distance and mineral hardness. Sediment size is related to water energy. ex. angular/sub-rounded pebbles.
Mature Lake
contains large number of small ecosystems
standing water ecosystems. examples – ponds, lakes, swamps, marshes, various wetlands types
Braided Stream
“Over-silted” stream. Too much sand.
Rock breakage by faults, joints, fractures
facilitates erosion of streams/rivers. Joints and fractures can do the same thing.
Aquatic abiotic components
temperature dissolves oxygen, pH
Water depth
Water energy/gradient (Lotic only)
Water chemistry (dissolved O2, dissolved solids)
Water clarity
Water temperature
Bottom topography and type
Deep, narrow canyons
Evidence of a rapid base level drop/local uplift
Process of lake and land ecosystem change
1st Order stream
Small stream with local spring source
base level
vertical limit to downcutting
Topographic basin that catches rainfall
stream sediment sizes
related to water energy
youthful stream characteristics
High gradient v shaped valleys (slide 8)
Littoral ecosystem
shallow shelflike lake ecosystem with plants. Must be close to surface, protects smaller creatures against larger creatures and is a nursery area.
cutbank erosion
erosion on the outside of a meander bend
water table
top of underground water saturation zone. Is usually not flat. Is a subdued replica of a ground surface. Less recharge area on top of a hill and that means a higher chance of well drying out. As surface water streams have a gradient so does this. Ground water flows in a general direction as ground slow down stream.
short term rainfall and temp. events
el nino
periodic changes in pacific circulation. May be driven by Solar activity. Under normal conditions: NE and SE trade winds combine to form E to W moving winds along Inter-Tropical Convergence Zone across Pacific Ocean. Every 3 to 7 years, these winds weaken.
rain shadow effect
the primary cause of north american deserts. Opposite side of orographic
Diurnal temp. variation
difference between night and day temps. Greenhouse effect shields earth from excessive variations.
wispy high altitude clouds
most common atmospheric gas which is composed of 78%. Important atmospheric functions include shielding earths surface from UV, x-rays, cosmic rays from space while allowing visible and infrared wavelengths to penetrate atmosphere.
hadley cells
vertical atmospheric circulation driven by equatorial heating. Vertical air movement of cells lead to 1. a persistent low pressure zone at equator ( 0 degrees) 2. Persistent mid latitude high pressure zone at 30 degrees north (across Africa) 3. strong persistent polar high causes polar eastarly
creates monsoon conditions
Summertime heating of large continents. Generates intense convection that draws warm, moist air inland from Indian Ocean. Orographic lifting caused by Himalayan mtns. results in flooding of ganges river. Flooding issues.
30+ year average of atmospheric events. Sun provides the energy that drives the Earth’s climate.
Variations in Solar activity and the Earth’s orbit primarily affect this.
low pressure system
counter clockwise circulation rising air
orographic uplift
air mass uplift by encounter with mountains. opp. side rain shadow effect.
axial inclination
condition that causes earth’s seasons. Variations in earth’s surface temperatures and climate are due to earth’s axis in relation to the sun and unequal distribution of land vs. water and differential thermal characteristics of land and water. Seasonal changes happen largely because of this
release of water vapor from trees/plants
lowest layer of atmosphere. “Weather maker”. Turbulent, rich in water vapor/droplets.
layered clouds
contains atmospheric ozone, ozone shield. steady wind but little turbulence. Ozone not present as layer but prevalent 10 – 15 ft above earth’s surface. Ozone is more dense and effective but unstable. Thinning seems seasonal, greatest in September.
middle latitude high pressure zone
persistent falling air at 30 degrees latitude
equatorial low
tropical zone of low pressure convection
rossby regime
horizontal/ latitudinal wind belts. 0 to 30 degree North – Northeast Trade Winds
30 degree to 60 degree North – Westerlies Wind Belt – Jet Stream
60 degree to 90 degree North – Polar Easterlies
There is interaction between jet stream and polar easterlies.
recipe for rain
water vapor and condensation nuclei
air mass uplift by heat
Coriolis effect
N hemisphere, clockwise ocean circulation. Combined actions of horizontal wind belts and hadley cells and earths rotation leads to this. Clockwise rotation of ocean currents in n. hemisphere. ex. gulf stream carries heat from subtropics northward carries enough to warm NW coastline of north america.
Udder shaped clouds beneath “supercells”
High pressure system
clockwise circulation, falling air
Youthful Stream
No floodplains, high gradient, high energy, low diversity, v-shaped valleys, mature floodplains, moderate gradient, local meanders, greater diversity.
Old Age Stream
Wide floodplains, low gradient, meanders and related features.
Piedmont Stream
lower energy/moderate. Drought triggered drop in local base level causing downcutting.
How humans change base levels
Building dams. As lake fills, the local base level rises upstream. Gradient decreases = deposition.
Ground water (wells)
Usually “out of sight out of mind” unless our individual home or city depends on one or more wells for irrigation or water supply. Ground water furnishes 50% of US population’s drinking water and 25% of industry’s needs. Helps to store freshwater that sustains streamflow, after run off effects of the last rain end.
body of rock or sediment that can hold and transmit usable quantities of ground water.
impermeable zones or layers of rock or sediment that do not pass water easily. Also called “confining” bed.
Surface of Well
The importance of proper well completion – Apparent lack of near surface grouting and concrete surface pad = potential contamination of unconfined (shallow) aquifer. Coastal plain needs larger surface pad.
Unconfined Aquifer
Aquifer that is “open” to the un-saturated zone, i.e., it is not overlain by an aquitard. The water must be pumped to reach the surface. Is directly recharged by rainfall.
Confined Aquifer
Overlain by an aquitard and pressurized by “up-gradient” water. Wells into confined aquifer are called artesin wells.
Atmospheric Circulation
Reason why wind blows. Caused by earth’s rotation, uneven distribution of landmass. Properties of heat transfer between air/water/land. Solar energy
Low Pressure Zone
Air rising counter clockwise. Weather maker. Most favorable for rain/snow.
High Pressure Zone
Clockwise falling air, fewer clouds. Divergence at surface.
Hydrologic Cycle
dynamic move-ment of water through the atmosphere, over & below the land surface, through the life cycles of plants and animals, and to and from the oceans & other water bodies.
Climate Drivers
Solar heat Methane
Orbital eccentricity Ocean currents
Axial tilt Ocean heat
Axial wobble Plate Tectonics
Water vapor Continent locations
Water droplets Land elevations
Carbon dioxide Chemical weathering
Vulcanism Bolide impacts
All of these drivers are of differing impact and all are subject to change. Some are random events, some are susceptible to cycles, some are affected by both random events and cycles of activity.
Some climate drivers combine to produce a greater effect.
Some climate drivers cancel each other out.
Cloud formation
composed of minute water droplets and/or ice crystals. Components/Processes needed :
Moist air
Condensation nuclei
Uplift mechanism – Convection, Cyclonic, Weather Front, Orographic

localized flooding

high pressure