Opportunities and Constraints Flashcards
What location specific conditions might be included in an opps and constraints (10)
lot size and shape
historic structues and views to landmarks
significant veg
hyrdrology
gelogy and soils
topo
climatic conditions
widlfires
wildlife habitat
noise and other nuisances
what other steps in the design process to opps and constraints ID’d in site analysis inform?
programming - what compatible uses there are on site
may prevent development from proceeding altogether
What areas have the highest recharge rates?
areas with high permeability soils, minimal slope. and sparse vegetation
With regard to topo - what direction does water always flow
perpendicular to contour lines
What is groundwater? What is base flow?
groundwater is subsurface water flow that discharges to streams lakes wetalnds and the ocean.
under normal non storm events - this discharge is called base flow
What constraints can high water tables cause?
prevent adequate site drainage
preclude use of septic
complicate subsurface excavation
require water proofing for foundations // subsurface structures
What type of grounwater question will you likely get on the exam?
identify high water table as constraint, where only right answer for locating a structure with a subsurface feature will be outside an area with a high water table
What is a 100 year floodplain
The area that has a 1% chance to flood in a given year
Define permeability infiltration and percolation
Permeability - the rate water moves through soil
infiltration - the rate of speed at which water flows into soil through its pores
percolation - downward movement of water in soil
What are 5 soils related risks / site constraints
expansive soils
liquefaction
differential subsidence
settlement
landslides
Bedrock (technically not soil but a geology risk
earthquakes - also techncially not soil but geology
What are risks of expansive soils? how can this be remediated?
they swell up and cause ground heave
find a different site
what is liquefaction - what is the reltaionship between soil density and liquefaction risk?
liquefaction takes place when loosely pack water logged sidents near the ground surface lose their strength and make solid soils behave like liquids (in response to earthquakes
the greater the soil desity - the lower the risk of liquefaction - desne clay soils are low risk
What is subsidence - vs differential subsidence - how is diff subsidence related to soil profiles
subsidence is soil settling and sinking downward due to lack of soil stability
Differential subsidence is when rate or degree of settling is different between points.
a single structure built across two soil profiles can cause differential settling
What is settling
building heavy sink soil down
For purpose of LARE what should be noted about landslides / landslide risk
landslide risk is related to rainfall unstable soils, extreme topo. veg loss and development activity
roads and major circulation should never be places in areas prone to landslides and areas with highly erosive soils
What should be noted about earthquake risk
placing structures parlell to anticipated direction of seismic waves increases risk of damage
What is the most imporant factor in determining site design
topography
What is color coding for elevations map
cool colors - low elevs
warm colors - high elevs
When are RUN-RISE Vs RISE-RUN slopes used
run rise typically denotes a softer slope - 4:1 or 12:1
What is a military crest?
The point on a hill just below the top of the hill that offers to greatest visibility of the slope below
What microclimate aspects are associated with winds?
northwest - cold winter winds
southwest - cool summer breezes
What 5 factors impact the effectiveness of a boise barrier
distance, height, continuity, length and mass
at what distance should noise barriers be construced
EITHER AS CLOSSE AS POSSIBLE TO THE source or to the RECIVING LOCATION to max noise diffraction
what height should noise barriers be
at a minimum they should block line of sight between source and reciever
what level of continuity should a noise barrier have
single and continuous is more effective thatn gapped
what length should a noise barrier be
1 to 2 times the distnace between the source and reciever, to minimize diffraction that would travel around the barrier
what mass should a noise barrier have?
greater mass has greater noise mitigation
