General Knowledge Flashcards
Fasciation
Disorder that causes a single stem to appear as if it were several stems fused together. Fasciation is caused by frost, insect, or physical damage to a stem early in its development.
Capital improvements program
Provides information on which city services are to be upgraded, repaired, or constructed
Site survey
Generally contain:
- Contour lines
- High and low points
- All water boundaries (including floodplains)
- Property lines with bearings and distances
Attributes for producing a solar radiation map
- Slope
- Slope aspect
- Vegetation
4 basic types of roadways
- Freeway = most rapid; largest traffic volume. Between urban areas. Limited access and grade separated intersections (expressways and parkways)
- Major arterial = through traffic system across and between urban areas. Control of entrances and exits
- Collector street = traffic control and curb use provided by signals and stop signs
- Local street = stop signs, local traffic movement
Traversing
Survey technique that describes an area of land by means of a series of connected lines
- May be open or closed depending on what is being surveyed
Roads = open traverse
Property boundaries = closed traverse
Palustrine wetland
Wetlands associated with inland sites that are not dependent on stream, lake, or oceanic water
Section
Contains 640 acres
Site inventory
Focused process of collecting and mapping essential attribute data for the site and its context
Beneficial in wetland mapping
- Wetland inventory
- Soils maps
- Aerial photography
- On-site field assessments
Infiltration capacity
The rate that water penetrates the soil surfaces (usually measured in cm or inches per hour)
Permeability
The rate that water within the soil moves through a given volume of material
Percolation
The rate that water in a soil pit or pipe within the soil is taken up by the soil (used mainly in wastewater absorption tests)
Recorded plat (survey plan)
- Legal document that indicates new property lines on a subdivided lot
- When searching for a client’s current property lines and/or boundaries, this map is needed to determine any changes in the property line
Soil texture
The term used to describe the composite sizes of particles in a soil sample, usually by using several representative handfuls
Site assessment
Completed to determine if a site is appropriate for the intended development and what the associated costs will be. A site assessment generally does not include a site plan
Lot
A parcel, tract, or area of land established by a plat or otherwise as permitted by law
Oxbow
A crescent-shaped lake or pond in a river valley formed in an abandoned segment of channel
Riffle
A short segment of stream channel characterized by rapid and often rough flow
Development density
A measure of intensity of development or land use; defined, for example, on the basis of area covered by dwelling units, impervious surfaces, or building floor area
Ephemeral stream
A stream without base flow; one that flows only during or after a rainstorm or snowmelt
Mitigation banking (wetland banking)
In wetland mitigation planning, the practice of building surplus acreage of compensation credits through replacement, enhancement, restoration, and/or preservation of wetland
Degradation
Scouring and downcutting of a stream channel, usually associated with high discharges
Environmental assessment
A preliminary study or review of a proposed action (projection) and the influence it could have on the environment; often conducted to determine the need for more detailed environmental impact analysis
Environmental impact statement
A study required by U.S. federal law for projects (proposed) involving federal funds to determine types of magnitudes of impacts that would be expected in the natural and human environment and the alternative courses of action, including no action
Alluvium
Any material deposited by running water; the soil material of floodplains and alluvial fans
Concentration time
The time taken for a drop of rain falling on the perimeter of a drainage basin to go through the basin to the outlet
Nitrogen (fertilizers)
- One of primary nutrients
- Symptoms of nitrogen deficiency in plants = slow or stunted growth, yellow green color with green veins (chlorosis), firing leaf tips
Potassium (fertilizer)
- One of primary nutrients
- Stimulates root growth, aids in disease resistance, improves flower/fruit production
- Should be applied near the roots
- Symptoms of deficiency = marginal burn on mature leaves, weak stalks, poor flower or fruit development, slow growth
Phosphorus (fertilizer)
- One of primary nutrients
- Stimulates early root growth, plant maturity, and promotes flower and fruit production
- Insoluble, applied near roots
- Symptoms of deficiency = slower or stunted growth, delayed maturity, poor flower/fruit
Acres in a square mile or section
640 acres
Calcium, magnesium, sulfur (fertilizer)
- Secondary nutrients
- Generally abundant in most soils
- Calcium = essential part of cell formation and structure
- Magnesium = essential for photosynthesis
- Sulfur = used in protein synthesis
Soil amendments
Three classifications, all used to improve soil structure, pH, and/or fertility
- Chemical = gypsym, lime, sulfur
- Mineral = perlite, vermiculite, sand
- Organic = humus, peat moss, manure
Humus
Decomposed organic matter which can aid in flocculating clay soils and help increase water-holding capacity and fertility of sandy soils
Colluvium
Any material made up of a mixture of runoff and mass wasting deposits
Aggradation
Filling in of a stream channel with sediment, usually associated with low discharges and/or heavy sediment loads
Locustrine wetland
Wetland associated with standing waterbodies such as ponds, lakes, and reservoirs
Information provided by aerial photograph
- Soil type
- Vegetative cover
- Topography
Proctor test
Performed to determine the maximum density of a soil needed for a project
Friable
When a soil is moist and crushes easily from the gentle pressure between the thumb and forefinger; easily broken into smaller pieces
Compressive strength of soil
The soil’s ability to withstand compressive forces from directly opposite sides
Shear strength
The ability of a soil to withstand the pressure from a downhill force. It is affected by the soil composition, its structure, and loading condition
Convex slope
Tends to bow outwards and be less stable than a concave slope, which bows inward
Strong cold wind
The strong cold winds that come in the winter time generally come from the northwest direction
Sand cone test
Used to determine the density of natural or compacted soil and is used mainly for stability analysis
ALTA / ACSM survey
A surveying standard jointly proposed by the American Land Title Association (ALTA) and the American Congress on Surveying and Mapping (ACSM) that incorporates elements of the boundary survey, mortgage survey, and topographic survey. Often required in real estate transactions
As-built survey
- Conducted 2-3 times during the building of the house; once after the foundation has been poured, once after walls, & at completion
- A survey conducted several times during a construction project to verify for local and state boards that the work authorized was completed to the specifications set on the plot plan or site plan.
- Usually entails a complete survey of the site to confirm that elements were built in the proper location
Subdivision plan
A plot or map based on a survey of a parcel of land. Boundary lines are drawn inside the larger parcel to indicate the creation of new boundary lines and roads.
In some jurisdictions, the re-ordering or filing of a subdivision plat is highly regulated
Townships and ranges
Measure north-south first
- Townships are measured north and south of the baseline
- Ranges are measured east and west of the baseline
____|_____baseline
|
|
| meridian
Leveling
Act of determining the elevations of certain points
Typically done to determine the topography of a site
Alluvial fan
A fan shaped deposit of sediment laid down by a stream at the foot of a slope.
Common in dry regions, where streams deposit their sediment load as they discharge downstream
US Wetland Classification System
US National Wetlands Survey
- Level 1 = ocean, riparian, ponds, and exclusive wetlands
- Level 2 = consistency
- Level 3 = based on ecosystems/vegetation
Chaining
Process for taking vertical measurements and is typically used on extremely hilly sites
Cadastral land survey
Normally to re-establish and mark the corners of original land boundaries. The first stage is to research relevant records such as land titles (deeds), easements, survey monumentation (marks on the ground), and any public or private records that provide relevant data. Typically conducted by the Federal government, specifically through the Cadastral Surveys branch of the Bureau of Land Management (BLM)
Groundwater basin
A group of aquifers linked together in a large flow system
Sight triangles
Term used to describe the area of oncoming traffic on an intersecting roadway that should be clearly visible to a driver stopped at the intersection
Soil forming factors
- Climate
- Parent material
- Vegetation
- Topography
- Drainage
Intersection distances
125’ CL to CL for low-volume collector
350’ CL to CL for high-volume collector
Cul-de-sac
50’ typical radius
38’ minimum radius
Linetypes on survey
____ _ __________ _ ________ ridge/watershed
_______ _ _ __________ _ _ ___ property line
________ _ _ _ ______________ swale/drainage
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ easement/trail
Liquid limit (soil)
The minimum moisture content at which a soil will flow under its own weight
Land uses/areas commonly connected with higher volume of bicycle traffic
- Schools
- Parks and recreation facilities
- Community activity centers
- Employment concentrations
- Shopping & community centers
- Average bicyclist covers 3-6 miles
- Class I bikeways are min. 8’ wide
Backsight
A surveying sight on a previously established survey point
Quadrangle
An area that can be subdivided into 16 townships, and has limits generally measuring 24 miles on each side. They are generally named after local geographic features
Marshes
- Marshes are dominated by herbaceous material (cattails, reeds, rushes, etc.)
- Often have the look of a grassland or meadow
- Rich soils with high pH, which has made marshes attractive to agriculture
Lacustrine wetland
System found in a depression, has low salinity level, and has a plant cover of less than 30%
Bearings
- Horizontal angle between the direction of the line and a line pointing to true north
- Bearings are always measured form either north or south
Acid soil
Soils with a pH less than 7
Most common in areas with high rainfall and are often high in organic matter
Emergent wetland
Wetland dominated by herbaceous vegetation growing in shallow water
Baseflow
The portion of streamflow contributed by groundwater, it is a steady flow that is slow to change even during rainless periods
Stadia measurements
A way of determining a distanced based on the height observation of a 6’H object
Hydric soils
Soils that are sufficiently wet in the upper part to develop anaerobic conditions during the growing season
Phase 1 Environmental Site Assessment
- Historical review
- Local environmental oversight, agency interviews
- Government environmental database review
- Conclusions regarding the presence or potential presence of environmental liabilities at the subject property
Loam
Approximately equal parts and and silt plus up to 25% clay. Often found in flood plains, good farm lad. Perfect for plants
Archaeological survey
Used to accurately assess the relationship of archaeological sites in a landscape or to accurately record finds on an archaeological site. A special type of field survey is the rescue survey, used when an area of possible archaeological importance is under threat. This is usually connected to construction work, and is undertaken to decide whether an excavation is necessary or not before work can commence on site
Tape survey
This type of survey is the most basic and inexpensive type of land survey. While accurate for distance, these surveys lack substantially in their accuracy of measuring angle and bearing. No longer acceptable for any substantial construction work by local, state, or federal committees
Wetlands delineation and location survey
A survey that is completed when construction work is to be done on or near a site containing defined wetlands. Spending on your local, state, or federal regulations, wetlands are usually classified as areas that are completely inundated with water more than two (2) weeks during the growing season. The boundary of wetlands is determined by observing the soil colors, vegetation, erosion patterns or scour marks, hydrology, and morphology. Typically blue or pink colored flags are then placed in key locations to denote the boundary of the wetlands. A survey is done to collect the data on the locations of the placed flags and plan is drawn to referent the boundary of the wetlands against the boundary of the surrounding plots or parcels of land and the construction work proposed within.
Who is in charge of benchmarks?
- The National Geodetic Survey (NGS)
- The United States Geological Survey (USGS)
State Plane Coordinate System (SPCS)
Each state has at least one zone. By subdividing the country, the systems can ignore the curvature of the earth and still be accurate. Depending on whether the state is longer east-west or north-south, they use different projection techniques
Swamps
Swamps are dominated by trees and shrubs. There are many varieties of swamps across different climactic areas
Bogs
Bogs are northern wetlands containing a wide diversity of vegetation. They are characterized by deep organic deposits, typically peat and tend to be acidic. Bogs often form in ones or small lakes where the vegetation is organized in concentric bands ranging from trees in the outer band to emergent and floating vegetation near the middle.
Wetland mapping
Three primary factors: vegetation (most common), soils (hydric-muck, pat), hydrology
Protection established in Section 404 of the US Clean Water Act
Fen
Like a bog, only fed by groundwater so not so acidic. It is a stage in filling in a lake
Soil group: cohesive soil
Have the smallest particles. Includes clay, which is used in embankment fills and retaining pond beds. Includes silt.
Plastic when wet (readily deformed by moderate pressure but can be pressed into a lump; will form a “wire” when rolled between thumb and forefinger)
Can be molded, but become very hard when dry
Usually require a force such as impact or pressure
Soil group: granular soil
Range in particle size from clay to gravel
Known for their water-draining properties
Obtain maximum density in either a fully dry or saturated state
Soil group: organic
Not suitable for compaction
Soil consistency (soil's response to stress): cemented
hard, little affected by moistening
Soil consistency (soil's response to stress): firm
when moist, crushes under moderate pressure between thumb and forefinger, but resistance is distinctly noticeable
Soil consistency (soil's response to stress): friable
When moist, crushes easily under gentle pressure between thumb and forefinger and can be pressed together into a lump
Soil consistency (soil's response to stress): hard
When dry, moderately resistant to pressure; can be broken with difficulty between thumb and forefinger
Soil consistency (soil's response to stress): loose
Noncoherent when dry or moist; does not hold together in a mass
Soil consistency (soil's response to stress): plastic
When wet, readily deformed by moderate pressure but can be pressed into a lump; will form a “wire” when rolled between thumb and forefinger
Soil consistency (soil's response to stress): sticky
When wet, adheres to other material and tends to stretch somewhat and pull apart rather than to pull free from other material
Soil consistency (soil's response to stress): soft
When dry, breaks into powder or single grains under very slight pressure
Hydrologic Soil Group A
- Sand, loamy sand, or sandy loam types of soil
- Low runoff potential and high infiltration rates even when thoroughly wetted
Hydrologic Soil Group B
- Silt loam or loam
- Moderate infiltration rate when thoroughly wetted
Hydrologic Soil Group C
- Sandy clay loam
- Low infiltration rates when thoroughly wetted
Hydrologic Soil Group D
- Clay loam, silty clay loam, sandy clay, silty clay, or clay
- Highest runoff potential
Aerobic
The ability of organisms or tissues to function only with the presence of free oxygen
Anaerobic Soil
Soil that is devoid of interstitial oxygen. In wetlands this condition most normally occurs because of the sustained presence of water, which limits contact with the atmosphere
Angle of repose
The angle between the horizontal and the maximum slope that a soil assumes through natural processes
Bearing capacity (soil capacity)
A measure of the load per unit area that a material can withstand before failure. Important feature when determining the sizing of a footing
Compressive strength
Resistance to a crushing or buckling force, the maximum compressive load a specimen sustains divided by its original cross-sectional area
Mineral soil
Having properties determined predominantly by mineral matter. Usually contains less than 20% organic matter
Shear strength
The ability of soil to hold together under pressure from a downhill force
Simple slope
- Has a smooth appearance with surfaces extending in one or perhaps two directions.
- Greater than 1% should only be irrigated with sprinkler and drip systems
Complex slope
- Have short slopes which extend in several directions
- Consist of convex and concave slopes
Erosion factor K
Indicates the susceptibility of a soil to sheet and rill erosion by water
Values of K range from 0.05 to 0.69
The higher the value, the more susceptible the soil is to erosion by water
Erosion factor T
An estimate of the maximum average annual rate of soil erosion by wind or water that can occur without affecting productivity over a sustained period
The rate is in tons per acre per year
Erodibility index (EI)
A numerical expression of the potential of a soil to erode
The higher the index, the greater the risk for erosion
EI scores of 8 or above are equated with highly erodible land
Erodibility factors
- soil texture (content of sand, silt, and clay)
- organic matter content
- soil structure
- soil permeability (the rate at which water can move through the soil)
Atterberg limits
Describe the soil changes from solid to semi-solid to plastic to liquid as water is added to a dry soil
Atterberg limit: Plastic limit
- Moisture content in the soil at the threshold between semi-solid and plastic
- Determined by rolling a thread of soil at the threshold between semi-solid and plastic
Atterberg limit: Liquid limit
- Moisture content in the soil at the threshold between plastic and liquid
- Large liquid limit indicates high compressibility and high shrink-swell tendencies
Atterberg limit: Shrinkage limit
- Water content, expressed as a percentage of the weight of the oven-dried soil, at which further loss of moisture will not cause a decrease in its volume
Unified Soil Classification System (USCS)
- Classifies soils according to properties that affect their use as construction material
- Classified according to: grain size distribution, plasticity index, liquid limit, organic matter content
- Assumptions: course material is better than fines, low liquid limit is better than high, narrow range from the plastic limit to the liquid limit is better than a wide range, well-graded material is better than poorly-graded material (well-graded = lots of sizes mixed together, smaller particles filling in gaps between larger particles, more dense)
USCS soil classifications
G - gravel
S - sand
M - silt
C - clay
O - organic
PT - peat
W - well-graded
P - poorly-graded
L - low liquid limit compressibility; lean (clay)
low liquid limit (silts); plasticity
H - high liquid limit compressibility; fat (clay)
high liquid limit, elastic (silts)AASHTO classification system
American Association of State Highway Officials classification system identifies soils based on their suitability for highway sub grade use
AASHTO Group A soil
- Has a high infiltration rate (low runoff potential) when thoroughly wet
- Consists mainly of deep, well-drained to excessively drained sands or gravelly sands
AASHTO Group B soil
- Has a moderate infiltration rate when thoroughly wet
- Consists chiefly of moderately deep or deep, moderately well-drained or well-drained soils that have moderately fine texture to moderately course texture
AASHTO Group C soil
- Has a slow infiltration rate when thoroughly wet
- Consists chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture to fine texture
AASHTO Group D soil
- Has a very slow infiltration rate (high runoff potential) when thoroughly wet
- Consists chiefly of: clays that have a high shrink-swell potential; soils that have a permanent high water table; soils that have a clay pan or clay layer at or near the surface; soils that are shallow over nearly impervious material
Soil compaction
- The method of mechanically increasing the density of soil by reducing the total pore space in a soil (used in almost all types of construction projects)
Purpose:
- Increases load-bearing capacity
- Prevents soil settlement and frost damage
- Provides stability
- Reduces water seepage, swelling, and contraction
- Reduces settling of soil
Static compaction force
- Deadweight of the machine, applying downward force on the soil surface, compressing the soil particles
- May be changed by adding or subtracting the weight of the machine
- Confined to upper soil layers
Vibratory compaction force
- Uses a mechanism, usually engine-driven, to create a downward force in addition to the machine’s static weight
- Use a certain amount of fore to overcome the cohesive nature of particular particles
Proctor test (soils)
- Determines the maximum density of a soil needed for a specific job site
- Tests the effects of moisture on soil density
- Expresses value as a percentage of density which is determined before any compaction takes place to develop the compaction specifications
Compressive stress
A force that tends to compress the surface
Tensional stress
- The opposite of compressive stress; occurs when one part moves away from another parter that does not move
Strain
The response to stress
Yield point
Point at which a material fails (deformability and firmness of a soil)
Metapopulations
Groups of subpopulations of species in same areas
Tree design functions
- Provide shade
- Screen undesirable views
- Serve as windbreaks
- Aesthetic value –provide focal point or visual amenity, spatial enclosure
Economic value of trees (calculation method)
Calculated by considering
- tree size
- tree species (hardy, well adapted = worth most)
- tree condition or health (e.g. roots, trunks, etc.)
- tree location (functional and aesthetic value)
Sources of nonpoint pollution (EPA categories)
- Agricultural runoff
- Urban runoff
- Forestry runoff
- Marinas
- Hydromodification
Access easement
Ensures physical access to and from a site across adjacent properties
Utility easement
Provides physical access to install, replace, and maintain utility system infrastructure
Conservation easement
Restricts development potential and is often used to protect hiking trails and other recreational areas and to maintain important ecosystem functions (e.g. groundwater recharge)
Scenic easement
Protect vistas and view sheds by preventing development that blocks or degrades those views
Solar easement
Protect solar access to adjacent property
5 elements of cognitive mapping (Kevin Lynch, “The Image of the City”)
- Edges (e.g. shorelines, roads, hedgerows)
- Paths (e.g. streets and walkways)
- Districts (e.g. neighborhoods)
- Nodes (e.g. entrances, plazas, street/walkway intersections)
- Landmarks (e.g. unique buildings, structures, natural features)
Neighborhood character
Influenced by street and walkway arrangements; mix of land uses; size, placement, and design of outdoor spaces; use of indigenous materials; native and naturalized vegetation
5 elements of cognitive mapping (edges, paths, districts, nodes, landmarks) helpful in assessing character and function of the built environment and site context
Visual resource assessment
Type of site assessment
Concerned with both visibility (view sheds to and from site) and visual quality (uniqueness and aesthetics of view sheds).
Site inventory vs. site analysis
Site inventory provides the physical, biological, and cultural data (attributes) needed for program-driven analysis.
Site analysis is a diagnostic process that identifies the opportunities and constraints for a specific land use program.
Site analysis = program + existing conditions => site suitability (constraints and opportunities)
- Program: goals and objectives, land uses and activities, phasing
- Existing conditions: physical, biological, and cultural attributes
Site carrying capacity
Sustainable development does not jeopardize the ability of future generations to meet their needs. Therefore, sustainable development protects and celebrates each site’s ecological integrity and cultural heritage
Design around a site’s features, integrating them instead of simply designing around them
Environmental determinism (Ian McHarg)
Allowing the analysis of biophysical conditions to drive land use allocation decision
Suitability analysis
Suitability analysis is the process of determining the appropriateness, or fitness, of a given tract of land for a specified use. It is spatially-explicit and program-dependent.
- ) Identify the suitability criteria for each anticipated land use
- ) Collect and map the relevant site attribute data
- ) Identify and map the site locations with attribute values that meet the suitability criteria for the targeted land uses
USDA’s Land Evaluation and Site Assessment (LESA) system
Helps local and state governments protect prime, unique, or locally important farmland from development.
- Used to determine boundaries of agricultural zoning districts, identify farms eligible for purchase of development rights (PDR) or transfer of development rights (TDR), and other land policy objectives
- Critique: Groups together agricultural productivity and potential for development, instead of evaluating separately. Also prone to data redundancy
Utility survey
For existing utilities:
- subsurface or surface?
- location
- location and width/depth of any easements
- requirements for new or altered connections
- existing capacity
Where there are no utilities:
- location of nearest/most accessible line
- for septic tanks, study soil suitability
- consider topography to identify or decrease costs of extension
Soils for septic systems
In general, you want sandy loam that is not too coarse, well-drained soil, and naturally undisturbed soils to absorb the effluent. When the soil is too coarse (e.g. too sandy), wastewater passes too quickly to receive sufficient treatment.
Soil that has a high clay content is also undesirable as clay holds water for too long causing it to drain too slowly. Clay particles can also swell and block soil passages slowing down the effluent’s movement even further. When the passage of wastewater is completely blocked, drainfield failure follows. This condition is known as hardpan.
Code Review (pre-design phase)
a. ) Identify relevant laws, codes, rules, and regulations governing the site and proposed uses
b. ) Graphically summarize applicable zoning requirements and development ordinances
c. ) Deed restrictions
d. ) Building and construction regulations
e. ) Barrier-free requirements
f. ) Site coverage requirements
g. ) Open-space requirements
h. ) Landscape/planting requirements
i. ) Building and parking setbacks
j. ) Parking requirements
k. ) Buffers
l. ) Easements
m. ) Rights of way
n. ) Sign ordinances
o. ) Fire-lane requirements
p. ) Lighting codes that govern max. energy use and min. illumination levels
Policy
- A specific system of principles to guide decisions and achieve rational outcomes
- A statement of intent, and is implemented as a procedure or protocol with goals and objectives
- Has goals that describe the range of of desired outcomes or what is to be achieved by implementing the policy
- Objectives are measurable
Performance metrics
- A measure of the performance, progress, effectiveness, or quality with which landscape solutions fulfill their intended purpose and contribute to sustainability. Quantifying post construction project performance is essential to building a knowledge base for sustainable landscape strategies
- Metrics must be measurable (or able to be determined by other measurements)
- Metrics must have a clear definition, including boundaries of the measurements
- Metrics indicate progress toward a performance goal
- Metrics answer specific questions about the performance
- Measure performance in a way that is meaningful to assessing the goals of the project
Landscape performance metrics
Use data to estimate:
- The positive effects of design elements
- To ensure a landscape performs to the anticipated standards
- Data allows the quantifying of the benefits of the designed landscape
- Provides hard evidence for a client trying to balance a project’s budget, schedule, and demands
Using performance metrics enables designers to show a design’s value and make the case for sustainable design solutions
Examples:
- Compare actual performance to design intent
- Compare performance with other similar examples
- User satisfaction
- Maintenance analysis of the efficiency strategies
- Long-term performance records for maintenance personnel to monitor efficiency
Physical attributes
Analysis based on the physical attributes of the site
- Topography, hydrology, soils, geology, microclimate
Biological attributes
Analysis based on the biological attributes of the site
- Ecological communities, vegetation (flora), wildlife (fauna)
Cultural attributes
Analysis based on the cultural attributes of the site
- Land use, open space, regulations, property, sensory perception, infrastructure, people
Circulation analysis
Depends on the context and location of the site and its intended use
- Looks at pedestrian access, vehicular access, bicycle access, service vehicle access
- Consider public transportation and external traffic and how it impacts site circulation
- Access and where is it located (conflicts, visibility, sight triangle, etc.)
Factors that affect the rate of stormwater runoff
- Length/duration of storm (determines total amount of water for infiltration or runoff)
- Overall size of watershed
- Amount of vegetation in the watershed (more vegetation, less runoff)
- Topography affects rate, direction, and velocity of runoff
Time of concentration
The amount of time needed for water to flow from the most remote point in a watershed to the watershed outlet
Factors that affect the amount of stormwater runoff
- Watershed boundary (overall size)
- Surface type – pervious, impervious
- Amount of rainfall, length/duration of the storm
- Topography can affect total volume of runoff given that infiltration is reduced as slope increases
