Module 1: Natural Land Assessment Flashcards
To gain a better understanding of a larger area for development, which 3 broad fields of study must be considered?
Analyze the land’s shape, structure, characteristics and existing use; each is linked together. Goal is to utlize it to our needs
Topography
Geology
Hydrology
Describe topography in context of gaining understanding of a large area for development
Most important form of mapping available to the planner in understanding existing land
The shape of the land (described by contours and elevations)
Topographic map includes contours and elevations, surface water, roads, buildings, railroads, etc
Shows the impact of structures in terms of roads, buildings, schools and churches
Our need for transportation by railroad and siting of airports together with industrial development will be shown
Scales are like 1:20,000, 1:250,000, 1: 2,000,000
Rock forms, land shapes
Some geological information
Describe geology in context of gaining understanding of a large area for development
What is happening 10-12m below the surface
Do not want to build over valuable deposits
More complex than topographic maps
Portrays depth and strata, folds and lifts of crust, structure of subsurface layers
Describe hydrology in context of gaining understanding of a large area for development
Occupancy of water on and below surface
Gauge water supply
Flood prone zones
aquifers , effects of pumping, fluctuation in ground water tables, saltwater intrusion
How do the 3 broad fields of study affect development?
Affects decisions regarding suitability, impact of development, different uses
Make their use efficient for humans and nature
Ownership, current and future land use
Immediate applications of topographic map
Ownership, current land use and future land use
Produce slope plans by direct interpretation of the contour information
Considerations in geology. Gathered by?
Valuable deposits
Soil characteristics
Size, shape, positions of rock masses, minerals, fluids, openings
Oil?
Hazards? Ex: fault lines
Water?
Gathered by boreholes, miner workins, caves, geophysical measurements
Geologic maps are more complex than topographic
What makes geological maps more complex?
Depth and strata; land masses move, erode, the curst folds, lifts, separates over time
Hydrological maps useful for monitoring what?
Effects of pumping
Fluctuation in ground water tables
Salt water intrusion
ground water contamination by sewage, industrial uses
What is land use? What does urbanization reflect?
Covers a wide range of applications
Urban
Residential, industrial, commercial land use; schools, hospitals, etc
agri,
range land,
forest land,
water,
Barren
Urbanization
Reflects the need to accommodate residential housing, which in turn requires or generates industrial/commercial land use
Population growth then requires educational and healthcare facilities
Types of urban land use? Which 3 dominate land use in urban area?
Residential
They have maximum flexibility for compatibility with natural characteristics
Commercial
Industrial
Recreational
Parks, open spaces
Incorporated with natural environment assets that are to be preserved
Institutional
Schools, hospitals
Require specific consideration for location in community
Topographic considerations for planning?
Not too steep
Orientation of slopes
Good access by vehicles and walking
Why does the orientation of slopes matter?
Southerly slopes favour exposure of houses to winter sun
Sun penetration, prevailing winds
Maximize light, solar energy, limit exposure to cold winds in winter, limit heat in summer
10 to 20 degrees east of magnetic south
Orient residential streets east-west direction
Parks and schools with southern aspect
Buildings on north-south streets can have staggered setbacks to provide sunny outdoor area for each unit
Windows on south and east sides
Cold winter winds should be blocked by land masses, vegetation
Geologic considerations for planning?
Limit bluffs, precipices, open pits, hazardous shorelines
LIMIT BODILY HARM
Avoid sites likely to move alot in an earthquake
Landslides?
Subsoils should be able to be excavated
Soils should be suitable bearing capacity (soil foundation support)
Does it have much, peat, poorly compacted fill, shifting sand?
Hydrological considerations for planning?
Water table must be low enough to protect buildings against basement flooding, interference with sewage
Water table is below basement, even when not used
No swamps or marshes
Sufficient slope to allow surface drainage
During rainfall
Groundwater observation may take years
Free from flooding by streams, lakes, tides
Basically, no developing on land that has a record of flooding
What are the topographical, geological, hydrological concerns of
Residential
Commercial
Industrial
Agricultural
see https://docs.google.com/document/d/129uoYV7AptzuSGVuV7OydVx0GydhA0RZ8zoV9aNXFlk/edit
topographical concerns for all 4 are slope
residential: site stability and bearing stability, flooding and drainage control
commercial: site stability and bearing stability, drainage control
industrial: site stability and bearing stability, water supply, pollution and drainage control
agri: soil type to support crops, irrigation supply, flood control and soil erosion
How else can flooding occur not from local conditions?
From present and future drainage from adjacent areas
3 broad categories for area assessment due for appropriate land use in consideration to natural characteristics of land?
Capability
Is the land able to be used
Suitability
Is the land appropriate to meet the neds of the use proposed
Feasibility
Is it reasonable to use the land
What else, besides natural land characteristics, is also taken into consideration at the basic level?
Providing services to the area
4 basic servicing requirements
Access
Road grades
Not too steep
Extent of cut and fill and bearing capacity of subsoil
Must provide traffic circulation and access to individual lots
Water supply
Provision of enough safe drinking water
Important when outside of municipal services especially
This may be the only deciding factor!!
Sewage disposal
Equally as important as water
If building on site disposal, must think long term
Stand alone sewage treatment plants for isolated developments are rare
Must examine long term effects of sewage disposal, well water supply and fluctuating water tables
NO CONTAMINATION
Drainage control
Most cost effective sewage collective system?
Uses gravity, to a central sewage disposal plant
What is important in drainage control?
Control and collection of surface runoff; storm water management
Most economical drainage control system?
Gravity storm sewer systems
Pumping is last resort
Need watercourses, trunk sewers, retention and water recharging
Where is flooding especially paramount? Why?
Valleys with natural watercourses
Long term development will increase peak flow
What type of topography is detrimental to all residential?
lowland/floodplains
What existing land use is detrimental to all new developments?
commercial
Which urban and subdivision development or land use are most dependent on topography and why?
Institutional facilities (schools, hospitals) require specific consideration for their location in the community
Assessing for subdivision purposes and had to rely on only one type of mapping, which would you choose? Topographical, geological, hrdological, and why?
Topographical
It would show slope, location of existing buildings and infrastructure, bodies of water
