Topography, Geology, Hydrology, Climate, Microclimate Flashcards
(4) Key attributes that may be derived from a topo survey / map
Elevation
Slope
Aspect
Drainage patterns
This feature of topography has greatest impact on site insolation; will also influence microclimate
Aspect
Part of every watershed; dry or semi-dry land area where water collects when it rains; typically found near rivers, lakes, coasts and depressions; provides temporary natural storage of runoff; serves as aquifer recharge; provides important natural habitats for animals and plants
Floodplains
On clear winter nights, air cools off and condenses, flowing downhill. Frost pockets may be created wherever the air is blocked as it flows downhill. These locations freeze first. Building siting: location buildings so that air drains away and early morning sun will warm sooner
A wind that blows from a higher elevation to a lower elevation
Air Drainage / Drainage wind
Sedimentation of stream channels
Aggradation
The study of the physical features of the earth’s surface
Physiography
Global-scale climate classification system. Its categories are based on the annual and monthly averages of temperature and precipitation.
Koppen Climate Classification
Slope Aspect and Microclimates
Western slopes are hottest in summer
Southern slopes receive the most sun in winter months
Southeastern slopes offer the most desirable microclimates
Northwestern slopes receive cold winter winds
Q = CIA
The “rational method equation,” used to determine the rate of runoff.
Q = peak discharge in cubic feet per second
C = the rational method runoff coefficient
I = rainfall intensity measured in inches per hour
A = drainage area measured in acres
A landscape underlain by limestone which has been eroded by dissolution, producing ridges, towers, fissures, sinkholes and other characteristic landforms.
Karst
The area between the high and low tide lines along coasts, estuaries, and bays; generally subject to wave action and periodic inundation
Littoral Zone
A type of geomorphic process; movement by gravitational forces
Mass Wasting
A mass of rocks and sediment carried down and deposited by a glacier, typically as ridges at its edges or extremity.
Moraine
A summary report of the exploration of the subsurface soils and how they are to be used as a construction material; generally concerned with construction characteristics, as opposed to a soil test report, which is concerned with planting;
Geotechnical Report
Processes that make or alter landforms
Geomorphic Processes
A type of igneous rock that cooled quickly when brought to the surface by volcanic eruption; tend to have FINE GRAINS; (ex: basalt & gabbro)
Extrusive Rock
Rock type transformed from other rock materials in response to pressure or temperature; classified based on composition and texture (foliated, non-foliated)
Metamorphic Rock
A confined aquifer containing groundwater under positive pressure. Water is trapped, surrounded by layers of impermeable rock or clay which apply positive pressure to the water contained within the aquifer. If a well were to be sunk into this aquifer type, water in the well-pipe would rise to a height corresponding to the point where hydrostatic equilibrium is reached.
Artesian Well
Rock type formed by sedimentation of material at the earth’s surface and within bodies of water; classified based on depositional mode (mechanical or chemical)
Sedimentary Rock
A type of geomorphic process; erosion, transportation, and deposition by wind
Eolian Process
Wave Action; movement of sand along a coastline due to wave and tidal action
Littoral drift
A type of geomorphic process; erosion, transportation, and sedimentation from rivers and streams
Fluvial Process
A type of igneous rock that cooled slowly within the earth; COARSE GRAINS easily seen with the naked eye (ex. granite, rhyolite)
Intrusive Rock
Rock type formed by the cooling of liquid magma; cooling rates affect composition and grain size; two sub-categories: extrusive and intrusive
Igneous Rock
A body of permeable rock which can contain or transmit groundwater.
Aquifer
Types of Erosion Caused by Water (4)
1) Splash erosion 2) Sheet erosion 3) Rill and gully erosion 4) Stream and channel erosion
Factors Influencing Soil Erosion (4)
1) Soil characteristics 2) Slope length and gradient 3) Erosive forces present (wind, rainfall, solar) 4) Vegetative cover
Soil Erodibility Affected By (8)
1) Average particle size 2) Gradation 3) Organic content (%) 4) Texture 5) Infiltration rates and permeability (i.e. sand = greater infiltration = less runoff than clay) 6) Vegetative cover 7) Topography 8) Climate
A type of landform; A steep slope or cliff that results from erosion or faulting and separates two relatively level areas of differing elevations
Escarpment
A type of landform: A low point or ridge between two summits
Saddle
Elements of topographic analysis (4)
1) Elevations 2) Aspect 3) Topographic and Slope Issues Impacting Land Use Planning and Constructions 4) Assessing Slope Instability
The branch of science concerned with the properties of the earth’s water, and especially its movement in relation to land
Hydrology
Elements of hydrologic inventory (6)
1) Drainage basins 2) Stream and wetland locations 3) Flow volumes 4) Floodplains 5) Lake levels and tides 6) Storm drain systems
Describes the continuous movement of water on, above and below the surface of the Earth Under normal conditions 50% of rainfall becomes groundwater and contributes to aquifer recharge, 10% evaporates, 30% is transpired by plants, and only 10% is runoff, directed to surface and streams (urbanization alters these percentages)
Hydrologic Cycle
Factors Influencing Watershed Response in Storm Event (5)
1) Topography (size of watershed and relative slopes) 2) Vegetation type and maturity 3) Soil type and depth of bedrock 4) % impervious / pervious surface 5) Change of surface type from previous to impervious (forest to lawn; lawn to asphalt)
Water moving within water table, via gravity, through the soil; supplies perennial streams
Baseflow
Stream Characteristics Upstream (3)
1) Steeper gradients 2) Channels tend to be rockier 3) Streams are more likely to erode their channels and “jump”
Stream Characteristics Downstream (4)
1) Deeper, wider, more sinuous 2) Channel gradient flattens 3) Substrate is finer 4) Sedimentation, not erosion, is the prevailing geomorphological process, contributing to land building where streams meet large water bodies
The Impact of Urbanization on Stream Dynamics (7)
1) Peak flows increases 2) Runoff volume increases 3) Baseflow levels decline 4) Time to peak flow decreases 5) Channel erosion increases 6) Flood frequency and high water level increases 7) Channel flow becomes more erratic
Principles of Stormwater Management (3)
1) Slow down water 2) Improve infiltration and percolation 3) Provide storage capacity to allow runoff to infiltrate at a slower rate
Stormwater Management In Practice (5)
1) Direct surface runoff to groundwater recharge areas 2) Detention measures (peak flow) 3) Retention measures (infiltration) 4) Biotechnical stream restoration (replanting as opposed to hard infrastructure) 5) Habitat restoration / enhancement in riparian systems and wetlands
The angle formed between the sun and the earth’s surface
Sun Angle
The angle formed between the sun and the earth’s surface; takes local topography into account
Ground-sun Angle
The density of light hitting the surface; amount of radiation per unit area (affected by atmospheric interference)
Incidence / Insolation
The angle between the sun’s rays and an imaginary line perpendicular to the collector’s surface; an angle of 0 means the sun’s rays are perpendicular to the collector surface = maximum solar gain achieved
Solar Incidence Angle
Solar energy absorbed by a surface
Solar Heating / Solar Gain
Orientation towards solar radiation; measured in N,S,E,W, and sub-increments; combined with slope data
Aspect of Slope
The ratio of total-reflected to incident radiation. It is a unitless measure indicative of a surface’s diffuse reflectivity. Expressed between 0-1. 0=100% absorbed (“low”; heat gain is high) 1=100% reflected (“high”; heat gain is low)
Albedo
Modern measure of a surface’s ability to reject solar heat; combines surface reflectivity and the material’s ability to shed heat / radiate / emittance; Used by both LEED and SITES to mitigate urban heat island effect high value = cooler low value = warmer 29 = min value for hardscape and roofing required as per LEED / SITES
Solar Reflectance Index (SRI)
Strategies for Ameliorating Urban Heat Island (4)
1) Roof: Light colors, solar panels, green roofs 2) Light colored paving materials 3) Shade hardscape and buildings 4) Surface water features
The study of processes and patterns in the natural environment
Physiography
Geographical areas within which climate, hydrology, plant communities, and wildlife populations are characteristic of the area. To a lesser extent, topography, geology, and soils and help distinguish them. 4 Levels: #1 = general, #4 = detailed Bailey Map (1976) Omernick Map (1982)
Ecoregions
Elements of microclimate Inventory (5)
1) Solar Radiation 2) Surface temperatures 3) Vegetation changes 4) Ventilation 5) Fog and frost frequency and location
Factors that influence vulnerability to fire (7)
1) Development % 2) Fuel load (type and condition of veg. cover) 3) Slope 4) Aspect 5) Access to responders 6) Proximity to assets at risk 7) History of fire
Types of landslides (5)
1) Falls (rocks) 2) Rock slump 3) Lateral spread (sheet-like) 4) Debris flow (material moves as liquid) 5) Soil Creep (slow, imperceptible)
Factors that contribute to landslide vulnerability (7)
1) Accelerated erosion 2) Undercutting (streams, road cuts) 3) Added weight 4) Uplift / tild (tectonic change) 5) Mechanical cut and fill 6) Deforestation 7) Improper construction siting
Loose, unconsolidated sediments that have been deposited at the base of hillslopes by either rainwash, sheetwash, slow continuous downslope creep, or a variable combination of these processes. Indicator of landslide vulnerability
Colluvium / Colluvial Soils
Landslide Prevention / Correction Measures
1) Excavation (remove unstable material, flatten slopes, bench slopes, lightweight fill)
2) Drainage
3) Restraining structures
4) Vegetation
Elements of physiographic inventory (4)
1) Region 2) Elevations 3) Slopes 4) Lithology (study of rocks)
The maximum rate of discharge during the period of runoff caused in a storm
Peak Flow
channel a river / stream / Water body and the immediately adjacent land that must remain free from obstruction so that a 100 y flood can be conveyed downstream
Floodway
The remaining portion of the floodplain outside of the food fringe; permitted to be developed by FEMA and state regulators given that certain standards are met (elevation, flood proofing, etc)
Flood Fringe
