CHAPTER 4: ABIOTIC SYSTEMS Flashcards
What is a soil series?
Group of soils originating from the same parent material with similar soil horizons, differing primarily in soil texture.
Each soil series is named for a nearby geographic feature, such as a town name, and can be divided into phases based on texture differences.
Define soil horizon.
A layer parallel to the soil surface with differing physical, chemical, and biological characteristics from layers above and below.
Horizons are defined by physical features like color and texture.
What is a soil profile?
A vertical section of soil through all its horizons extending into the parent material.
What are the three types of soil textures?
- Sand: 0.05 to 2.0 mm in diameter
- Silt: 0.05 to 0.002 mm in diameter
- Clay: smaller than 0.002 mm in diameter
What is soil porosity?
The measure of void spaces in soil and how soil particles are distributed.
Define well-graded soil.
A soil with a wide range and even distribution of particle sizes where smaller particles fill voids created by larger grains.
What is permeability in soil?
The rate at which water moves through soil.
True or False: Hydric soils are characterized by prolonged saturation with water.
True
What is bearing capacity?
A measure of soil’s ability to decrease in volume under pressure from a given weight.
Define angle of repose.
The maximum slope at which loose material can be piled while remaining stable.
What is soil elasticity?
The ability of soil to return to its original shape after being subjected to a load.
What are the effects on erosion?
- Precipitation patterns
- Topography
- Soil disturbance
- Site location
- Natural disasters
How can erosion be reduced?
- Preserve existing vegetation
- Reduce land disturbance
- Stabilize excavated areas
- Minimize disturbance to steep slopes
- Schedule clearing during dry season
- Introduce erosion control measures
What is gully erosion?
Widening, deepening, and head cutting of small channels due to erosion.
What are the components of soil fertility in the context of LARE?
- Nitrogen (N)
- Phosphorous (P)
- Potassium (K)
What is the pH measurement range?
0-14
What are alkaline soils characterized by?
High pH level and high amounts of calcium, magnesium, and sodium.
To treat overly alkaline soil, _______ should be added.
sulfur
What defines acidic soils?
Soils with a pH of less than 5.5, often resulting from fertilizers.
To treat overly acidic soil, _______ should be added.
lime
Define topography.
The physical features of a surface area, including elevations and the position of features.
What does slope analysis help identify?
Steep and unbuildable slopes as well as potential locations for building sites.
What is the aspect of a slope?
The direction the slope faces relative to the sun.
What are the three types of streams based on flow?
- Ephemeral: flows only in response to precipitation
- Intermittent: flows part of the time
- Perennial: flows continuously
What is a 100-year floodplain?
An area with a 1% chance of flooding in any given year.
What is the purpose of FEMA maps?
To document floodplains and special hazard areas throughout the US.
What are point sources of pollution?
Single identifiable sources of pollution from which pollutants are discharged.
What is sedimentation?
The process by which soil particles are carried by water and deposited in rivers.
Define aggradation.
A geological process where sediment builds up in a river, causing the riverbed to rise.
What is the time of concentration in surface drainage?
The time needed for water to flow from the most remote point in a watershed to the outlet.
What is the Rational Equation for peak discharge?
Q = ciA
What are the benefits of a riparian zone?
- Groundwater recharge
- Sediment stabilization
- Flood attenuation
- Water quality maintenance
- Wildlife habitat
What is freeboard in floodplain terminology?
Any portion of the flood in excess of the base flood elevation.
What is biological growth in the context of environmental impact?
Increased turbidity, decreased flow capacity in streams/rivers, flooding in areas that never or rarely flooded in the past
Examples include algal blooms.
What is sedimentation?
The process by which soil particles are carried by flowing water and deposited in rivers, impacting water quality, river ecosystems, and navigation.
Define aggradation.
A geological process when sediment builds up in a river, causing the riverbed to rise; also called alluviation.
What characterizes a high water table?
Considered ‘shallow,’ contributes to storm surges and flooding, increases excavation costs due to waterproofing needs.
What are the impacts of a high water table?
Affects on-site stormwater infiltration and the provision of septic systems.
What is the consequence of excessive pumping of aquifer systems?
Can result in land subsidence and related ground failures.
What are aquifer recharge areas?
Important locations to identify and protect from development.
List the variables that compose climate.
- Temperature
- Humidity
- Wind
- Precipitation (rain/snow)
- Solar radiation
What is the purpose of the USDA Plant Hardiness Zone Map?
Landscape architects consult the map to determine how climate interfaces with plant selection.
What does Zone 1 represent on the USDA Plant Hardiness Zone Map?
The coldest zone.
What does Zone 13 represent on the USDA Plant Hardiness Zone Map?
The hottest zone.
Define albedo.
A measurement of an object’s reflectivity, measuring the fraction of solar energy reflected from a surface back into space.
What is the range of albedo values?
Albedo varies between 0 and 1.
What does a low albedo indicate?
It means the surface absorbs more solar energy.
What is the angle of incidence?
The angle at which a ray of light (usually the sun) hits a surface.
What is azimuth?
The direction of a celestial object from the observer, expressed as the angular distance from the north or south point of the horizon.
What is drainage wind?
A wind that blows from a higher elevation to a lower elevation.
Define microclimate.
Differences in weather-related phenomena such as humidity, temperature, rainfall, and wind over a relatively small geographical area.
How can winter winds be mitigated in landscape design?
By using windbreaks, such as trees.
What can be done to reduce energy consumption for heating and cooling?
Through passive and active solar designs.
What is the importance of sun/shade analysis in site design?
To mitigate solar radiation on a site design.
In northern climates, how should outdoor spaces be designed in winter?
To receive sun for thermal comfort and prevent ice formation on pedestrian surfaces.
What design strategies are suggested for desert regions?
Maximizing shade to protect users from heat.
How can vertical elements influence site microclimate?
They can cast shadows.
What role do fountains play in arid environments?
They can cool the air.
What effect do dark colored paving materials have on temperature?
They absorb solar radiation and raise air temperature.
What is a significant drawback of metal surfaces in landscape design?
They have temperature fluctuations and can become too hot or too cold.
What is the benefit of large trees in landscape design?
They intercept solar radiation.
How do plants influence air temperature?
They cool air temperatures through evapotranspiration.
What is one way plants can improve air quality?
By removing chemical pollutants or capturing dust pollution.
