CHAPTER 5: OPPORTUNITIES AND CONSTRAINTS Flashcards
What are some conditions and considerations that shape site constraints and opportunities?
Conditions include:
* Lot size and shape
* Historic structures and views
* Significant vegetation
* Hydrology
* Geology and soils
* Topography
* Climactic conditions
* Wildfires
* Wildlife habitat
* Noise and nuisances
These factors significantly influence site development decisions.
What might be a site constraint for constructing a 100,000 sf distribution center?
Constraints include:
* Steep slopes requiring excavation
* Lack of access to highways or rail
* Local opposition to construction
Site constraints often hinder development processes.
What is a watershed?
A watershed is a land area that contributes surface water to a location, defined by surface topography.
Watershed boundaries occur along ridges.
Define ‘time of concentration’ in hydrology.
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.
It is dependent on slope, surface, and channel characteristics.
What is evapotranspiration?
Evapotranspiration is the process where water is transferred from land and water surfaces to the atmosphere, with plants contributing to the process.
It can recycle up to 50% of precipitation back to the atmosphere.
Describe surface runoff.
Surface runoff is precipitation that flows off the land surface downhill.
It is influenced by precipitation, soil type, slope, and vegetation.
What does groundwater refer to?
Groundwater is subsurface water flow that discharges to streams, lakes, wetlands, or the ocean, known as ‘base flow’ under normal conditions.
Groundwater plays a crucial role in hydrology.
What is a riparian corridor?
A riparian corridor is the area that encompasses a river or stream and the adjacent land.
Erosion occurs on the outside bank, while sediment deposition occurs on the inside bank.
What is the significance of water table depth in development?
Water table depth can prevent site drainage, complicate excavation, and preclude the use of septic systems.
It also requires waterproofing for building foundations.
What is a floodplain?
A floodplain is an area of land adjoining a body of water that may be covered by floodwater.
Floodplains act as pressure relief valves for floodwaters.
What is a 100-year floodplain?
A 100-year floodplain has a 1% chance of flooding in any given year.
New developments can increase flood risks.
What are floodplain areas composed of?
Floodplain areas consist of:
* Channel
* Floodway
* Flood fringe
Each area serves a different function during flooding.
Define Base Flood Elevation (BFE).
Base Flood Elevation (BFE) is the elevation of the 100-year floodplain studied in detail, used to determine safe construction heights.
Freeboard is the height of floodwater above the BFE.
What are hard engineering structures in flood management?
Hard engineering structures include levees and riprap.
These can increase streambank erosion.
List methods to mitigate flood hazards.
Methods include:
* Expanding stormwater infiltration
* Minimizing impervious surfaces
* Decreasing runoff volume
* Restricting development in floodplains
* Using green infrastructure
Green infrastructure can slow water velocities.
What are the components of soil?
Soil is composed of:
* Sand
* Silt
* Clay
Soil composition affects its characteristics and suitability for development.
What is soil infiltration rate?
Soil infiltration rate is the speed at which water flows into soil through small pores.
It is crucial for stormwater management.
What risks are associated with expansive soils?
Risks include:
* Ground heave
* Liquefaction
* Differential subsidence
* Settlement
* Landslides
Expansive soils can cause significant structural issues.
What is differential subsidence?
Differential subsidence occurs when soil beneath a building sinks at different rates, leading to instability.
This can happen when structures cross different soil profiles.
What is the impact of bedrock on site development?
Presence of bedrock increases development costs and complicates excavation.
Excavation activities should avoid areas where bedrock is present.
What factors exacerbate earthquake damage?
Factors include:
* Building height
* Proximity to fault lines
* Hillside location
* Orientation of structures to seismic activity
Taller buildings are more susceptible to damage.
How does topography affect site planning?
Topography influences building location, road alignments, pedestrian circulation, and stormwater management.
Grading can cause significant site disturbances.
Define microclimates.
Microclimates are site variations due to changes in topography, vegetation, and orientation.
They can significantly affect climate conditions on a site.
What are design considerations for hot/arid sites?
Considerations include:
* Avoid heat-absorbing materials
* Create favorable microclimates with walls
* Deflect hot winds
* Use drought-tolerant plants
These help manage heat and water use.
What is the Urban Heat Island Effect?
The Urban Heat Island Effect occurs when natural land cover is replaced by surfaces that absorb heat.
It leads to increased air pollution and energy costs.
What contributes to the Urban Heat Island Effect?
Contributors include:
* Dark roofs
* Dark asphalt
* Lack of vegetation
* High density of buildings
Green roofs and tree canopies can mitigate this effect.
What defines the Urban-Wildland Interface?
The Urban-Wildland Interface is where human development meets undeveloped lands, increasing wildfire risk.
This area is vulnerable due to fire catalysts from urban settings.
Name the three protection zones in wildfire management.
Zones include:
* Building protection zone
* Building buffer zone
* Natural area fuel reduction zone
Each zone has specific management practices to reduce fire risk.
How does habitat quality relate to human development?
Human development impacts habitat quality and quantity, which is vital for biodiversity and recreational value.
Healthy habitats attract wildlife and support ecosystem functions.
What is the goal of the Natural Area Fuel Reduction Zone?
To reduce fuel load by removing debris, brush, and dead branches
What must be done to trees in the Natural Area Fuel Reduction Zone?
Trees shall be pruned to prevent ladder fuel formation
How does human development impact habitat?
It directly impacts the quantity and quality of habitat
Why are habitats critical?
They maintain biodiversity and support wildlife
What is an example of habitat attracting recreational value?
Healthy migratory bird populations attract bird watchers
Define Carrying Capacity.
Measure of development type and density supported without detrimental effects
What is Habitat Fragmentation?
Breaking up of a continuous habitat into smaller patches
List two effects of habitat fragmentation.
- Movement of organisms (migration)
- Altered ecosystem characteristics
What are patches in the context of fragmented habitats?
Fragmented habitats
Define Gaps in habitat fragmentation.
Areas between patches that are not connected by a corridor
What are Corridors in habitat fragmentation?
Connected patches
What does the General Habitat Fragmentation Rule state?
Patch size and distance between patches correlate to ecosystem impact
What should be avoided to preserve biodiversity?
Activities that cause habitat fragmentation
What priority should large, contiguous natural areas receive?
The highest priority for protection from development
What is the most effective way to restore habitat?
Addressing gaps in existing corridors
Why are wetlands important?
They are fragile ecosystems worthy of protection
What should never occur inside wetlands?
Construction
List three benefits of wetlands.
- Groundwater recharge and discharge
- Flood attenuation
- Wildlife habitat
What are the five major wetland types in the US Fish and Wildlife Wetland Classification System?
- Salt Marshes
- Marine
- Estuarine
- Riverine
- Lacustrine
- Palustrine
What causes Acidification in water?
Excessive carbon dioxide or sulfur and nitrogen compounds
What is Eutrophication?
Overabundance of nutrients leading to excessive plant growth
True or False: Noise travels by line of sight and dissipates over distance.
True
What should noise-sensitive uses be built away from?
The noise source
What three key items should a Landscape Architect record during a noise analysis?
- Source and type of noise
- Direction and distance from the source
- Duration and intensity of the noise
What can be used as a barrier to noise?
Grading, walls, and dense plantings
What is the first effectiveness factor of noise barriers?
Distance: barriers should be close to the noise source or receiver
What is the minimum height requirement for noise barriers?
To block the line of sight between source and receiver
Why is continuity important in noise barriers?
A single continuous barrier is more effective than multiple fragmented barriers
What is the recommended length of a noise barrier?
1-2 times the distance between the source and the barrier
What is significant about the mass of noise barriers?
Greater mass has a greater impact on noise mitigation
