LARE Section 2_2 Flashcards
Bearing capacity
the measure of a soil to decrease in volume under the pressure of a given weigh
Angle of repose
the maximum slope at which a loose material can be piled while remaining stable
What type of natural disaster results in hydrophobic soils?
wildfire
What is aggradation
the filling in of stream channel with sediment
What are some ways to reduce soil erosion?
- Preserve existing vegetation
- Reduce the total area of land
- Stabilize excavated areas with seeding, sodding, matting or mulching and divert runoff from these areas
- Minimize disturbance to steep slopes
- Schedule clearing and grading activities during the dry season and suspend them prior to and during precipitation events
- Introduce erosion control fencing , blankets, and stabilize drainage channels with erosion-resistant materials
-Locate non-point pollution sources (e.g. construction access roads) in areas that do not drain directly into water bodies
Gully erosion
the widening, deepening, and head cutting of small channels and waterways due to erosion
Rill erosion
the removal of soil by running water with formation of shallow channels
Sheet erosion
the removal of a fairly uniform layer of soil or materials from the land surface by rainfall or runoff
Geomorphology
the study of the physical features of the surface of the earth and their relation to its geological structures
What data does a geologic map generally include?
the age and distribution of rock layers and the attributes of these rock layers. Map data will also identify locations that are susceptible to earthquakes and landslides, and they will identify seismic fault lines
Karst
landscape underlain by limestone which has been eroded by dissolution, producing ridges, towers, fissures, sinkholes, and other characteristic landforms
Glacial erratic
a glacially deposited rock (often a large boulder) differing from the type of rock native to the area which it rests
Moraine:
a mass of rocks and sediment carried down and deposited by a glacier typically as ridges at its edges or extremity
Channelization
turning hydrological resources into highly engineered, enclosed and impervious storm drain systems
Time of concentration
refers to the amount of time needed for water to flow from the most remote point in a watershed to the watershed outlet.
Does infiltration increase or decrease with slope?
Infiltration is reduced as slope increases regardless of whether the surface of that slope is impervious or not
What does the Rational Equation Calculation determine?
the rate of runoff
What does Q=ciA refer determine?
the rate of runoff
What does Q stand for in Q=ciA?
the peak discharge measured as cubic feet per second
What does c stand for in Q=ciA?
the runoff coefficient (between 0 and 1). A measure of how permeable a surface is, with this number being higher value for areas with low infiltration, and lower value for areas with high infiltration
What does i stand for in Q=ciA?
rainfall intensity as inches per hour
What does A stand for in Q=ciA?
drainage area in acres
What is a riparian zone?
A riparian zone or riparian is the interface between land and a river or steam
What are some benefits provided by riparian zones?
Groundwater recharge and discharge
Sediment stabilization
Flood attenuation
Water quality maintenance
Wildlife Habitat
Climate moderation
Shoreline protection
What are first order streams?
primary drainange ways at the beginning of a hydrological system
What are second-order streams?
streams formed by the confluence of two first-order streams (naming continues until additional streams come together in a hydrological system)
What is an ephemeral stream?
a stream that flows only in response to precipitation
What is an intermittent stream?
A stream that flows only part of the time or through only part of its reach
What is a perennial stream?
a stream that flows continuously
What is a floodplain?
an area of land adjoining a body of water that has been or may be covered by flood water.
What does a 100-year floodplain mean?
an area of land that has a 1% chance to flood in any given area or will flood once every century on average
What three components are floodplains composed of?
Channel, floodway, and flood fringe
What is a channel?
the portion of the floodplain where a stream/river flows under normal conditions
What is a floodway?
the portion of the floodplain that is used to convey floodwaters during a 100-year flood
What is a flood-fringe?
the portion of the floodplain outside the floodway that doesn’t not convey floodwaters and usually contains standing or slow-moving water.
What is base flood elevation (BFE)
whole-foot elevations of the 100 year floodplain that have been studied in detail at selected intervals. In areas where building has occurred within the 100 year floodplain, BFE calcs are often used to determine the heigh to which living spaces must be constructed to be safe from a 100 year flood.
Freeboard
any portion of the flood in excess of the base elevation
What types of maps commonly document floodplains?
FEMA Flood Insurance Maps
How can flood hazards be mitigated?
-expanding opportunities for stormwater infiltration
-minimizing the uses of impervious surfaces
- decreasing the volume of runoff during storm events
-restricting development to areas outside the floodplain
What is point-source pollution?
any single identifiable source of pollution from which pollutants are discharged (e.g. factory smokestack)
What is non-point source pollution?
pollution caused by rainfall or snowmelt moving over and through the ground, during which it absorbs and/or assimilates natural and human-made pollutants and deposits them into lakes, rivers, wetland, groundwater and ocean.
What are some negatives of sedimentation in waterways?
Decline in water quality
Negative impacts to aquatic vegetation and animals
Negative impacts to aquatic recreation
Unwanted biological growth
Increased turbidity
Decreased flow capacity in streams/rivers
Flooding in areas that never or rarely flooded in the past
What is sedimentation/aggradation?
can be thought of as the opposite of erosion- sediment is deposited. Especially in the inner radius of the river banks as water flows.
What are some factors that can cause groundwater levels to fall?
When water demand exceeds aquifer recharge rates
Groundwater pumping
What are some results of excessive pumping of aquifer systems?
Land subsidence and related ground failures
What is the mapping resource landscape architects often consult to determine how climate interfaces with plant selection?
USDA Plant Hardiness Zone Map
Albedo
the measurement of an object’s reflectivity, it measures the fraction of solar energy reflected from the surface back into space
How is albedo measured?
between 0-1, with 1 being white and 0 being black (measuring the whiteness of a surface)
Angle of incidence
the angle at which a ray of light hits a surface
azimuth
the direction of a celestial object from the observer, expressed as the angular distance from the north or south point of the horizon to the point at which a vertical circle passing through the object intersects with the horizon
Drainage wind?
a wind that blows from a higher elevation to a lower elevation
What can a drainage wind cause?
Can cause dryer climates
Can lower temperatures- destroy crops
Lower air temperature
Worse air quality
Which orientation receives the most sun in winter months?
southeastern
Carrying capacity
a measure of the type and density of development that can be supported without detrimental effects to society, the economy, or the environment and without decreasing the capacity of the environment to sustain these uses into the future.
Ecological footprint
is the impact of a person/community or use on the environment, expressed as the amount of land required to sustain their use of natural resources.
xerophytes
plants that require little moisture to survive and are often referred to as “drought tolerant”.
Mesophytes
plants that are adapted to neither dry nor wet environments and grow best with a moderate use of water.
Hydrophytes
plants that are adapted to living in aquatic or in wetland conditions with a surplus of available water.
What are the benefits of native plants?
-pre-adapted to respective climate
-often less resource intensive to grow than exotic plants
-tend to provide outstanding wildlife benefits
-greater sense of place
What are some of the benefits of wetlands?
Groundwater discharge
Sediment stabilization
Flood attenuation
Water quality maintenance
Wildlife habitat
Climate moderation
Shoreline protection
What are the 5 major types of wetlands?
marine: open ocean and associated coastline
estuarine: tidal water of coastal rivers, salty tidal marshes, mangrove swamps, and tidal flats
riverine: rivers and streams
lacustrine: lakes, reservoirs, and large ponds
palustrine: marshes, wet meadows, fens, bogs, swamps
What are the characteristics of a bog?
found in northern climates
acidic soils
rich deposits of organic materials (such as peat)
a diversity of vegetation types
fed by rainwater or snow
peat moss is dominant
What are the characteristics of a fen?
found in northern climates
acidic soils (but less than bogs)
rich deposits of organic materials (such as peat)
a diversity of vegetation types
fed by groundwater
sedges are dominant
Estuary
semi-enclosed coastal body of water connected with the open sea
strongly affected by tidal action and contain brackish water (seawater + fresh water)
Marsh
type of wetland characterized by vegetation no taller than 6’
they can flood and dry out
rich in nutrients
overgrown with leafy vegetation
Swamp
wetland dominated by woody vegetation
are like wooded marshes
They are soggy landscapes with waterlogged trees and other plants
Black spot
the fungal disease that causes black, round spots that form on the upper side of leaves, particularly on roses (as well as other highly ornamental plants). Black spot is a problem during extended periods of wet weather or when leavers are wet for 6 hours or more
Canker
often identified by an open wound that has been infected by fungal or bacterial pathogens. Canker occurs primarily on woody landscape plants and trees.
Chlorosis
is a condition typically caused by iron deficiency and is manifested by yellowed leaves with green veins. This iron deficiency can be produced by overly alkaline soils (high pH), overwatering and lack of soil aeration
Fasciation
is a genetic mutation of a plant’s growing tip, and it affects the stem, flowers, or fruits by inducing malformed growth.
Powdery mildew
is a fungal disease in which infected plants will display a white powdery that is most visible on upper leaf surfaces. This fungus thrives during low soil moisture conditions combined with high humidity levels on the upper parts of the plant surface
What are the street classifications?
arterial (minor and principal), local, and collector
What factors influence the landscape architect’s scope of work for site inventory and analysis?
size of the project
environmental features on site
existing site constraints
proposed project scope
What is the purpose of an as-built survey?
to document a final built work and ensure that a project was consturctred according to site plans
Who can adopt Zoning Ordinances?
several scales of government including towns, cities, and counties
how many acres are in a section?
640
“Microclimate” refers to?
differences in humidity, temperature, rainfall and wind over a small area
What are some methods to reduce forest fire hazards?
reduce available fuel load
maintain defensible space around structures
Rank the factors that are most important to determining the type of vegetation found on an undisturbed site (in order)?
Available moisture
temperature extremes
composition of soils
“Frequency Seen” Map
characterizes the visibility of locations from two or more viewing points
how visible is it to see into the site from multiple point
“Visibility Map”/”Viewshed Map”
shows the locations that can be seen from an individual viewing point
View corridor plan
plan used to protect or otherwise control the view shed of a specific area
How many townships are in a quadrangle?
16
Which slopes are hottest in the summer?
western
which slopes receive the most sun in the winter months?
southern
Which slopes offer the most desirable microclimates?
southeastern
Which slopes receive cold winter winds?
northwestern
What information does a USGS quadrangle map show?
Town, range, and section information
New construction since the last printing
Wetlands
Topography
What is the composition of loam?
Equal parts silt and sand, less clay. Example: 30% sand, 40% silt, 30% clay or 20% clay, 40% silt, 40% sand
Friable soil
large clumps are easily broken apart by hand, but cannot be easily broken apart into small particles
Porosity
describes void space
has direct relationship with porosity
allow them to drain very quickly
Well-graded
a soil that contains various particle sizes
Uniformly graded soil
consists of a single range of particle size
Karst
landscape underlain with limestone which has been eroded by dissolution, producing ridges, towers, fissures, sinkholes and other characteristic landforms
Glacial erratic
a glacially deposited rock differing from the native type of rock deposited by glacial movement
Moraine
a mass of rocks and sediment carried down and deposited by a glacier typically as ridges at its edges
Time of concentration
the amount of time needed for water to flow from the most remote point in a watershed to the watershed outlet
what factors effect time of concentration
topography (steeper slopes have slower infiltration), material
How many people are in a focus group
7-10
How should a successful focus group be conducted?
Invitations to focus group participants
Transportation to the meeting site
Audio and video recording equipment
Facilitator with script and core themes
Presentation materials/visual aids
Refreshments
Release forms
Transcript of focus group discussion (produced after the event concludes)
What is a visual preference survey?
useful tool in helping communities and the general public determine how they would like their neighborhood/city to look in the future, and they are typically conducted by showing precedent imagery to a person/group of people and asking for their feedback on that image.
What do visual preference surveys address?
Buildings scales, massing and placement
Building articulation
Streetscapes
Open space/parks
Parking and mass transit
what is the difference between a focus group vs. a charrette?
charrettes can engage neighborhood groups, members of the design team or a group of public officials. Whereas focus groups emphasize data- particularly related to poinions-charrettes are often more interactive and projective, and they typically require participants to translate their opinions into discrete preferences or even elements of a proposed design through a process of collaboration. As such, charrettes are particularly relevant to a project as it transitions from analysis into the concept design phase, and charrettes may be used to present stakeholders with a series of concept plans that are based on the outcomes of the site inventory and analysis process.
What are the four key elements of a charrette?
- Identification of a specific community problem to study, understand, and hopefully resolve
- Participation of interested citizens, particularly those experiencing the problem, who are willing to be involved in the decision-making process.
- Involvement of professional experts from within and outside the community; initially these experts listen and learn as citizens express concerns
- Commitment from the relevant power structure to put into effect the plans and recommendations of the charette. Representatives of the power structure are to be present to hear the concerns expressed by the citizens.
What makes a successful survey?
They have preceded by pre-notification
Contain clear, non-technical language
Have well-delineated purpose clearly stated in an introduction
Are concise and make use of graphics as needed
Are not overly difficult or time-consuming for the participant
Sanborn Maps
are detailed maps of U.S. cities and towns in the 19th and 20th centuries. Originally published by The Sanborn Map Company (Sanborn), the maps were created to allow fire insurance companies to assess their total liability in urbanized areas of the United States. Since they contain detailed information about properties and individual buildings in approximately 12,000 U.S. cities and towns, Sanborn maps are valuable for documenting changes in the built environment of American cities over many decades.
Comprehensive plan
are a planning document that establishes a government’s policy for the long-term future development of the land under their control. Usually over a twenty to thirty year period.
bring together all the major determinants of growth and development (housing, transportation, utilities, natural and cultural resources, community demographics and economic development) into a single planning document, and they establish a series of non-binding policy goals
How is intensity of use controlled in zoning?
minimum lot sizes or dwelling units per acre for residential or FAR for non-residential
What are height and other dimensional standards in zoning?
These standards define the portion of the parcel that can be occupied by buildings and may establish a maximum percentage of the site to be covered by a new building, the building’s FAR, and/or the building’s height. Dimensional standards are also enforced by minimum lot sizes and through required building setbacks from property lines
Zoning overlay
special districts established within the zoning code that offer additional protections to specific resources. Example: prime farmland, historic neighborhoods, environmentally sensitive areas
Zoning commision
regulatory body of public officials that governs planning and development-related issues
Variance
allow certain restricted forms of development to be permitted due to extenuating circumstances, specifically if compliance with the zoning regulations would pose a hardship to the landowner. Variances can affect or change minimum set-back requirements, building height and FAR limits, as well as similar dimensional issues. However, a variance cannot be used to alter the essential character of the zoning district in which the land is located, including allowing a nonconforming use.
Conditional-Use
allow for a property owner to request an exception to a zoning ordinance subject to approval by a zoning board/zoning commission. However, conditional use permits allow for nonconforming uses to be permitted within a specific zone, whereas variances do not (given that they generally address dimensional and density-related issues). Conditional use permits are generally granted when the non-permitted use would benefit the general welfare of the community and if the change would be consistent with objectives outline in the jurisdiction’s comprehensive plan.
FAR
Cluster Development
do not increase development density on a site. Rather, cluster developments take the total number of development units allowed on a site and group these units into clusters of greater density, thereby preserving open space.
What are the benefits of cluster developments?
Preservation of open space and site character
Protection of critical natural and cultural historic/resources on a site
Reduction of impervious surfaces across the site
Lowered construction costs for streets, utilities, and other infrastructure
Reduction in site disturbance/grading
Reduced visual impact of existing communities
Mixed-use development
combine residential and commercial uses
What are the benefits of a mixed-use development?
Provide a distinct sense of place
Encourage sustainability via efficient, high-density development
Mixed uses cater to a diverse public
Density encourages pedestrian activity and use of public transit
Creative active public spaces
Greater public safety due to increase in site usage
Conducive to urban in-fill redevelopment and reuse of historic structures
What is a PUD?
often framed as a variation of traditional zoning practices or “rezoned” special districts. PUDs are a tract of land that is controlled by one entity and planned and developed as a single development (at once or in stages) over a relatively long period of time (generally 5-15 years). PUDs allow the consolidation of multiple parcels into a single master-planned project, often for mixed-use development. PUDs provide greater flexibility in meeting the density and land use requirements for the site as a whole and- as such- allow for the protection of environmentally sensitive areas and the creation of walkable neighborhoods, among other benefits.
What is a TOD?
Transit-oriented development (TOD) encourages mixed-use, high-density development in areas surrounding multi-modal transportation hubs. TOD principles state that developments should be located within ⅛ mile of transit hubs in downtown areas, and ½ mile radius around mass transit stations in all other conditions.
What principles guide TODs?
Encourage high-density development
Mitigate urban sprawl
Mix commercial/office and residential uses
Provide housing for all price ranges
Reduce parking requirements
Encourage use of public transit
Create walkable communities and active public spaces.
Capital Improvement Program
outlines city services that are to be repaired, expanded or otherwise upgraded. It is a short-range plan (usually addressing a four to ten-year period), and it provides a planning schedule and identifies options for financing capital improvements. Essentially, the capital improvement program is the link between the government and its available resources (i.e. budget) and the content outlined in a comprehensive/strategic plan.
Citizens’ Advisory Committee:
formed to represent the local community (or special interests from within the local community). They provide feedback to decision makers, including a planning commission, city council, public agency, or private development interests.
Design Guidelines
establish standards for architecture and landscape architecture features of new development- often in master planned communities and planned unit developments. Design guidelines promote aesthetic continuity and outline a vision of what- precisely-comprises acceptable development in a given community. When voluntary, the applicable standards are usually referred to as “design guidelines”, and mandatory review standards are called “design controls”.
Task Force
ad hoc citizens’ committee formed or supported by a public agency with a well-defined objective related to a single problem or subject.
Technical Advisory Committee
are groups that represent technical or scientific interests or information relevant to the work conducted by a planning commission, city council, public agency, or private development interests.
Purchase of Development Rights (PDR)
is a mechanism used to control development on a given property. Through entering into an agreement for the purchase of development rights, a property owner is essentially selling their development potential (but not the property/land itself) to another party.
What are Purchase of Development Rights (PDR) often used for?
to encourage agricultural, open space, or environmental uses on a site that might otherwise be developed for housing or another “high value” use. Public entities and non-profits often purchase development rights and hold them in a trust, thereby withdrawing them from use, and PDRs are often used in situations where zoning controls or voluntary agreements like covenants are limited either through inappropriateness or by lack of authority/control.
Transfer of Development Rights (TDR)
However, TDRs allow development rights to be used in another location, rather than to be retired outright. Development rights are often sold in a “sending “ or “preservation” zone to be used in a “receiving” or “development” zone. Although TDRs are sold on the private market, a local government may establish a “TDR bank” to buy and sell development rights toward the same goal as PDRs, that is, encouraging agricultural, open space, and environmental uses.
Access Easement
allows physical access across a site to an adjacent property.
Utility Easement
provides physical access to a utility company to install, replace and otherwise maintain utility infrastructure crossing a property (e.g. power lines, sewer lines)
Conservation easement:
restricts development for the purpose of preserving important environmental features and protecting outdoor recreational uses (e.g. hiking trails)
Scenic Easement
restricts development in areas that would block or otherwise degrade a scenic view
Solar Easement
protects solar access to an adjacent property.
Covenants
also known as deed restrictions, are consensual agreements that restrict what can be done with private property. Covenants place additional rules or restrictions on the use of land that supplements any regulations established in a zoning code, subdivision regulations, or building codes
Covenants are usually introduced during real estate transactions, at which time this voluntary agreement is drafted into the new deed. Although private parties (rather than governments) impose covenants, they constitute a valid contract and are thus legally enforceable.
What are the three road classifications?
- arterial (interstates and expressways, roads that carry most traffic entering and leaving urban areas)
- collector (carry trips to and rom arterials into residential, commercial, and industrial)
- local (local roads include most residential and other side streets and are the road type with the lowest traffic volume)
Sight Distance Study
used to determine the location of vehicular access points and take into account visibility, location of the proposed access point, its relationship to other existing access points and the speed and volume of traffic flowing along the proposed point access
Environmental Impact Studies
generally address the extent of a site and its environmental resources. They will also provide recommendations for site monitoring and suggest strategies for mitigation
EIS is often required only for those projects that are expected to have significant (negative) environmental impacts and are thus intended to inform decision makers (such as plan reviewers or other public agency staff) and the public of the impacts of a proposed development and describe to them any reasonable alternatives that would avoid or minimize adverse impacts or enhance the quality of the human environment.
What does an EIS include:
A description (including maps) of the area(s) to be affected by a proposed development
An inventory and analysis of the site’s resources
Detailed studies of the environmental consequences of development. Note that this forms the basis for comparisons to any proposed development alternatives and/or mitigation
Description of development alternatives an/or mitigation, including the impacts of those alternatives and/or mitigation
Environmental Site Assessment (ESA)
a report prepared for a real estate holding that identifies potential or existing environmental contamination liabilities on a site, and it often entails historical research to determine if past site uses would have caused a release of hazardous substances and determine if any environmental issues (e.g. soil contamination) still exist on site
On-Site Determinants:
Physical conditions (e.g. site size and shape, steep slopes, microclimatic factors such as wind direction and sun/shade patterns)
Regulations and standards (e.g. zoning codes, building codes, and design guidelines)
Open space (to protect natural resources and/or buffer developed areas from hazards such as floods and landslides)
Boundary interface with off-site properties and public infrastructure
Off-Site Determinants:
Neighborhood, community and regional character
Nuisances (e.g. adjacent highway that produces noise, odors, and undesirable views)
Number and location of site entrances (adjacent street or transit stops suggest preferred locations for providing access to the site)
Presence of significant view
functional use diagram
a drawing that illustrates the relationship between project elements (often site program) without being drawn to scale or in relationship to the site
sometimes referred to as “spatial relationship diagrams”
Concept plan
organize the project’s proposed elements approximately where they are to be located on the site, and they tend to identify three key site elements:
- Open space
- Circulation
- Development pods/activity zones
What elements appear on all concept plans?
Open space: active and passive recreation areas, conservation areas
Buildings
Landmarks (including specimen trees)
Vehicle Circulation: streets and site entrances, passenger drop-off areas), parking, loading/service areas
Pedestrian Circulation: walkways, crosswalks, site and building entrances, meeting areas/nodes
Other Circulation: bike paths, public transit stations, lines and stops
Utilities (including easements)
Views: prominent views to and from the site
Five factors that should be considered when communicating project information with graphics?
- Message
- Medium
- Audience
- Setting
- Time
