Inventory and Analysis Flashcards
(249 cards)
1
Q
Perennial Stream
A
Year round flow, fed by shallow groundwater moving through soil
2
Q
Intermittent Stream
A
Flows part of the year
3
Q
Ephemeral Stream
A
Flows or during or after rainfall events
4
Q
Depth of groundwater analysis
A
- How deep wells must be drilled for water supply, impacts cost
- Determining feasibility of stormwater infiltration/retention
- Determining feasibility of siting septic system leaching fields
- Groundwater quality and contamination impacts it usefulness for water supply purposes
5
Q
Stormwater Controls
A
- Filtration through planted medium to remove sediments and pollutants before going into municipal stormwater systems
- Reduce downstream flashiness to protect streams
- Groundwater recharge
6
Q
Stormwater Mitigation
A
- Grassy filtration strip along drainage edge
- Vegetated swale with broad bottom to slow water
- Biofiltration basin with fast-draining soil and planted with species that can tolerate flooding, pipe at the bottom might collect clean water
7
Q
Stream Protection
A
Slow It, Spread It, Sink It:
• To hold back water, to slow it down with check dams
• To get runoff into the ground by enhancing infiltration and percolation.
• To provide storage capacity to allow more time for runoff to infiltrate or be released to the storm drainage system at a slower rate through the use of basins.
8
Q
Technological Stormwater Management Methods
A
- Direct surface runoff to recharge areas (to improve groundwater recharge)
- Detention measures (to reduce peak flows)
- Retention measures (to reduce runoff volume and peak flows)
- Biotechnical Stream Restoration (repair natural channels using “natural” technology in lieu of hard armoring)
- Habitat Restoration or Enhancement (Riparian systems, wetlands)
9
Q
Vegetation Analysis
A
Depends on scale of project • Plant Communities • Species Lists • Edge Profiles • Rare and Endangered Species • Fire History • Physionomic Profiles
10
Q
Remote Sensing for Vegetation Inventory
A
- Aerial Photographs or Satellite Imagery (vegetation associations, species identification, wetlands, patch/corridor mapping)
- Stereoscopic 9” x 9” (available from: U.S. Soil Conservation Service, U.S. Forest Service, and U.S. Bureau of Land Management) for topographic maps
- Non-photographic Sensors (electromagnetic)
- Infrared Radiation: meteorology and climatology, foliage health
- Light Detection and Ranging (LIDAR): Tree canopy heights, forest biomass
- Thermal Imaging: Heat stress in vegetation, surface water temperature, city energy audits, wildlife distribution and density.
11
Q
Sampling Vegetation - Quadrat Sampling
A
Site is subdivided into plots of a standard size, can be random, regularly distributed, or subjectively selected. Quadrats can be square, rectangular, or round. Contents of selected plots are inventoried.
12
Q
Sampling Vegetation - Transect Sampling
A
Samples are taken along a baseline. Points can be selected with a grid, randomly chosen coordinate pairs, or regular or random points along the line.
13
Q
Sampling Vegetation - Relevé Sampling
A
“Sample stand” community types are defined by a specialist. Several representative sample stands for each community are inventoried.
14
Q
Sampling Vegetation - Aerial Photography
A
Using large scale color or infrared photography can provide a basis for acceptable estimates of plant cover and soil surface conditions, though understory plants may be obscured in a forest setting.
15
Q
Sampling Vegetation - Windshield Survey
A
Commonly used in land-use surveys; enables rapid but not verifiable assessment of site. Note: Roadside planting is often not a good indicator of interior planting
16
Q
Vegetation Information/Classification Types
A
- Species Richness: How many species occupy the sample area.
- Frequency: How often a species occurs in a sample, or a proportion of the samples in which it occurs.
- Density: How many plants (of a species) per unit area.
- Cover: How much ground within the sample area is covered or shaded by a species.
- Total Biomass: The dry weight of plant material per sample unit.
17
Q
Physiognomy
A
The spatial/vertical structure of a plant community. It can include an inventory of the number of canopy layers, with the plant that dominates each layer.
18
Q
Factors Influencing Physiognomic Plant Distribution
A
- Duration of Growing Season (climatic zone)
- Point of Succession
- Ground Temperature
- Continuous Wind
- Soil Moisture
- Shallow Soils on Fractured Rocks
- Shallow Soil Without Subsoil Moisture Reserves
- Disturbance
- Wildlife populations and browse patterns
19
Q
Vegetation Physiognomic Types
A
• Forest • Woodland • Savanna • Scrub • Grassland • Tundra • Swamp* • Marsh* • Bog* * indicates wetland types
20
Q
Ecological Land Classification:
A
A process of delineating and classifying ecologically distinctive areas of the earth’s surface.
21
Q
Ecoregions
A
Geographical areas within which climate, hydrology, plant communities, and wildlife populations are characteristic of the area. To a lesser extent, topography, geology and soils also help distinguish ecoregions.
22
Q
Ecosystem
A
An interactive system including physical habitat as well as living organisms.
Land Use is also a factor in ecological classification as human activities impact both physical habitats as well as plant and animal populations.
23
Q
Biodiversity
A
A contraction of biological diversity. It is the variety within and between all species of plants, animals and micro-organisms and the ecosystems within which they live and interact.
24
Q
Ecological Mapping Systems of the United States
A
- Bailey Ecoregions Map (1976) (developed through USDA/US Forest Service)
- Omernik Ecoregions Maps (1982) (developed through the US Department of Interior, USGS and the Environmental Protection Agency)
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Agents of Environmental Change
* Climate Change
* Wildfire
* Invasive Species
* Development
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Vegetation Dynamics
* Seasonal (1 yr, i.e., spring to fall)
* Cyclical (20 yrs, i.e., fire cycle)
* Succession (1000 yrs, i.e., sand dune to forest)
* Geologic (20,000 yrs, i.e., ice age)
* Genetic (1,000,000 yrs, i.e., development of a new species)
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Succession
The observed process of change in the species structure of an ecological community over time. Typically a relatively bare site will begin with a few pioneer species of plants and over a long period of time develop into a climax community of plants and animals. A mature redwood forest would be a California Coast Range example of a climax community.
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Vegetation Analysis Factors
* More biodiverse habitats are generally considered to be healthier ecosystems within habitat types (forests, meadows, grasslands, tundra, etc.)
* Presence and predominance of invasive species is an indicator of less healthy or less mature habitat types.
* Development can destroy or fragment habitats. Smaller fragments are generally able to support lesser populations of wildlife or less diverse populations of wildlife.
* Removal of vegetation through logging, mining, or clearing for agricultural or other human uses can severely alter habitat suitability for both terrestrial and aquatic habitats.
* Wildfire and other catastrophic events can drastically alter ecosystems and return areas to pioneering stages in vegetation succession.
* Soil erosion severity can be impacted by removal of vegetation, winds, storm runoff, and slope steepness or slope instability.
* Pollution due to human uses can negatively impact soil health, surface and groundwater, and vegetation, wildlife, and human health.
* Rare and endangered species of plants and animals usually occupy fairly narrow ecological niches which is why they are rare and very sensitive to change in their environments.
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Landscape ecology
a broad, well established field of study that looks at regional ecosystem patterns and tries to set standards for maintaining ecological integrity. As human development fragments and degrades natural areas, they reach a point where they can no longer sustain a healthy, interdependent ecological web.
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Landscape
a heterogenous land area composed of interacting stable ecosystems
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Patch
an intact area of consistent ecological character that differs from its surroundings
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Matrix
the background ecological system of a landscape
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Connectivity
a measure of how easily plants, animals etc can access the resources they need, moving through patches, networks and corridors
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Fragmentation
is the breaking up of an ecosystem into isolated patches
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Classification of Wetlands
two approaches to classification:
• Geographically based systems (broad-based mapping similar to USDA soils maps)
• Site inventory/environmental characteristics as found on the ground (watershed position, existing habitats, vegetation based approaches, etc)
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Geographical Wetland Classification Schemes
US Fish and Wildlife maintains the National Wetlands Inventory (NWI) system, a collection of maps showing many wetlands identified using aerial photography.
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Cowardin Wetland Classification System (US Fish and Wildlife Service)
* Marine (open water and assoc. coastline)
* Tidal (influenced by tides, brackish or saline)
* Estuarine (tidal waters of coastal rivers and embayments, salty tidal marshes, mangrove swamps, and tidal flats)
* Riverine (rivers and streams)
* Lacustrine (lakes, reservoirs, and large ponds)
* Palustrine (marshes, wet meadow, fens (non-acidic bogs), playas, potholes, pocosins, bogs, swamps, and small shallow ponds)
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The Nature Conservancy Wetland Classification system
Based on vegetation associations; has been adopted as the Federal standard for habitat-based classification.
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Clean Water Act Wetland Classification System
The US Army Corps of Engineers and EPA generally define a wetland as a place where wetland vegetation occurs.
Wetlands must have the following three attributes:
1) at least periodically, the land supports predominately hydrophytes
2) the substrate is predominantly a hydric soil
3) the substrate is saturated with water or covered by shallow water at some time during the growing season of each year.)
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Hydrogeomorphic Wetland Classification (HGM) used by Army Corps of Engineers (7 classes)
Based on site’s geomorphic setting (topographical position and shape), dominant water source, and dominant hydrodynamics.
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Seven classes:
• Riverine (rivers and streams)
• Depressional (ie. vernal pools, pocosins, etc.)
• Slope (Artesian wells, seeps, other places where groundwater discharges to the surface but does not accumulate)
• Mineral Soil Flats (dry lakes, etc)
• Organic Soil Flats (peat bogs)
• Tidal Fringe (ocean edges)
• Lacustrine Fringe (lake edges)
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41
Topographical Analysis
* Temperature: vertical lapse rate (typically -3.5 degree F per 1000 ft. elevation gain)
* Orographic effects on precipitation: moist air pushed up a ridge will condense and turn to rain which results in different moisture regimes and vegetation types on either side of a ridge.
42
Aspect
Orientation of the face of a slope
• North side and south side of hills have different daily temperatures, night time temperatures are similar.
• Evaporative stress is greater on south-facing and west-facing slopes. It is less on east and north-facing slopes. This has implications for the types of vegetation that can grow there, soil moisture levels, organic matter levels in the soils, and wildlife habitats.
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Terms for Mapping and Measurement of Slopes (surveying)
• Degrees vs. Percent Slope: tanA=rise/run=S
• Typical angle of repose for different materials, by percent:
drained sand 33%, boulders 45%, loam 45%, well-compacted clay 65%
• Influence of vegetation
• Slope ordinances:
Cities or counties may restrict development on steep slopes for public safety
44
Soil Horizons
Soil horizons are the layers in a typical soil profile which have distinctly different physical, chemical and biological qualities.
• O = Organic Matter in a recognizable form, including leaves and partially decomposed matter.
• A = Heavy non-recognizable organic matter mixed with minerals
• B = Nutrients left by rain water leaching, hardpans & clay pans develop here.
• C = Partially weathered rock fragments
• D = Bedrock
• Subordinate designations are too specific for the exam. They can be found in Time Saver Standards.
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Soil Test Reports
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Test soil and tailor planting plan to be adapted to soils.
Typical Information in Soil Test Reports
• USDA Soil Classification
• pH
• Organic matter content
• Macro and Micronutrient content
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46
Geotechnical Reports
A geotechnical report is a summary report of the exploration of the subsurface soils and how they are to be used as construction materials.
• Boring Locations shown on a plan of the site:
• Summary of all subsurface exploration data, including subsurface soil profile, exploration logs, laboratory or in situ test results, and ground water information;
• Interpretation and analysis of the subsurface data;
• Specific engineering recommendations for design, especially thicknesses and reinforcing for pavements and footings;
• Discussion of conditions for solution of anticipated problems; and
• Recommended geotechnical special provisions.
• Permeability (for septic systems, stormwater filtration, etc – test for the percolation rate, or how many minutes per inch (MPI). Metric equivalents may be minutes per 25mm or minutes per liter. You can request permeability tests for undisturbed site soils or for fill soils.
47
Soil Bearing Capacity
the maximum average contact pressure between a structure and the soil surface on which it rests that the soil can support without failure.
Clay 1-2 tons/ sq. ft.
Silt 1.5-3 tons/sq. ft.
Sand (loose) 2-3 tons/ sq. ft.
Gravel (loose) 4 tons/ sq. ft.
Sand-gravel(compact) 6 tons/ sq. ft.
Well graded, well compacted 10 tons/ sq. ft.
clayey sand and gravel
Sedimentary rock 15 tons/ sq. ft.
Foliated rocks (layered metamorphic) 40 tons/ sq. ft.
Massive bedrock 100 tons/sq. ft.
48
Soil Texture
affects how well nutrients and water are retained in the soil. Clays and organic soils hold nutrients and water much better than sandy soils. As water drains from sandy soils, it often carries nutrients along with it. The technical term for this is leaching
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Sandy Soils (over 45% sand)
* Drains quickly
* Light weight
* Non-expansive
* Erodable
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Silty Soils (over 40% silt)
* Small grain size
* Moderate permeability
* Highly erodable
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Clayey Soil (over 35% clay)
* Low permeability or impermeable
* Heavy weight
* Expansive: heaves, shrinks (Swells when wet, shrinks when dry)
* Low water availability at low moisture content
* Colloidal content describes presence of clay particles in sample (Colloid: A suspension of finely divided particles in a dispersing medium; particles do not rapidly settle out of suspension and are not readily filtered.
* Erodable to highly erodable
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Loam (usually less than 40% clay with good particle size distribution)
* Blend of soil types. Also variations such as sandy loam, sandy clay loam, etc.
* Rated as highly valuable agricultural soil
* Very good drainage, moderately permeable, high water holding capability
* Slight erosion potential, 0-3% slope, no rocks
* Highly fertile
* Easily worked
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Soil Structure
Soil structure describes the arrangement of the solid parts of the soil and of the pore space located between them.
Soil structure is generally classified as one of the following:
Platy -flat and platelike, usually found in subsurface soils that have been subject to leaching or compaction
Blocky - structural units are blocklike or polyhedral
Prismatic - units are bounded by flat to rounded vertical faces
Granular - structural units are approximately spherical or polyhedral and are bounded by curved or very irregular faces that are not casts of adjoining peds. In other words, they look like cookie crumbs
Columnar - similar to prisms and are bounded by flat or slightly rounded vertical faces
Structureless - no units are observable in place or after the soil has been gently disturbed
54
Gypsum (calcium sulfate dihydrate)
is used as a soil amendment to improve soil structure. It also helps reduce salt toxicity in soils that are heavily irrigated. It also provides sulfur and calcium to the soil and often improves permeability. It does not significantly affect soil pH.
55
Soil Acidity (Ph) Acidic
Acidic
• Low pH 0-7
• Usually have a high percentage of organic matter
• Often associated with areas of higher rainfall
```
four major reasons for soils to become acidic:
rainfall and leaching,
acidic parent material,
organic matter decay,
and harvest of high-yielding crops.
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Macronutrients tend to be less available in soils with low pH.
Aluminum sulfate or Sulfur can be added to increase soil acidity.
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Soil Acidity (pH) akaline/basic
Alkaline/Basic
• High pH 7-14
• Heavy in salts and other solutes
• Usually associated with areas of lower rainfall
two primary ways that soils become basic.
- the soil is derived from a basic parent material such as limestone
- located in a climate where the alkaline elements are not leached out by rain.
Micronutrients tend to be less available in soils with high pH.
Lime can be added to the soil to make it less acidic and also supplies calcium and magnesium for plants to use.
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Hydric Soils
formed under conditions of saturation, flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part of the soil. This lack of oxygen in the soil can lead to the formation of a thick layer of non-decomposed organic matter in the upper horizon. While hydric soils usually have low pH (acidic), this is not always the case.
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Soil Macronutrients
- Nitrogen
- Phosphorus
- Potassium
- Calcium
- Magnesium
- Sulfur
availability of macronutrients is largely determined by three variables: the abundance of parent minerals present, the chemical conditions in the soil, particularly the pH, and the rate of movement of the nutrients that are in compounds available to plants within the soil media. Many micronutrients are almost immobile in soil, or react with organic matter and clays to form immobile compounds. This protects the micronutrients from being lost due to leaching.
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Soil Micronutrients
- Iron
- Manganese
- Zinc
- Copper
- Boron
- Molybdenum
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Nitrogen
Responsible for the vegetative growth of plants above ground. With good supply, plants grow sturdily and mature rapidly, with rich, dark green foliage. Nitrogen helps seed and fruit production and improves the quality of leaf and forage crops. Plants deficient in nitrogen tend to have a pale yellowish green color (chlorosis), have a stunted appearance, and develop thin, spindly stems. Lower leaves are more affected than upper ones. Natural sources include blood meal, alfalfa meal, feather meal, fish emulsion, and manure.
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Phosphorus
Healthy growth, strong roots, fruit and flower development, and greater resistance to disease. Enhances photosynthesis, nitrogen fixation, flowering, fruiting (including seed production), and maturation. Root growth, particularly development of lateral roots and fibrous rootlets, is encouraged by phosphorous. A phosphorous-deficient plant is usually stunted, thin-stemmed, and spindly. Its foliage (particularly lower leaves) is often red or purple. Natural sources include rock phosphate, guano, and bone meal.
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Potassium
Helps plants to resist diseases, protects them from the cold and protects during dry weather by preventing excessive water loss. Potassium is known to activate 80 different enzymes in plants. Potassium plays a critical role in reducing the loss of water from leaves and increases the ability of the roots to take up water from the soil. It also helps plants adapt to environmental stresses. Potassium deficiency causes the tips and edges of the oldest leaves begin to yellow (chlorosis) and die, so that the leaves appear to have been burned on the edges. Natural sources include potassium sulfate, granite dust, wood ash and kelp meal.
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Calcium
an essential part of plant cell wall structure, provides for normal transport and retention of other elements as well as strength in the plant. Deficiency symptoms: Deformed tips of leaves and little root growth.
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Magnesium
is essential for photosynthesis. It also activates many plant enzymes needed for growth. Deficiency symptoms: Yellowing of leaves, purple leaf margins.
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Sulfur
reduces soil pH. is essential for production of protein. Helps in chlorophyll formation.
Improves root growth and seed production. Helps with vigorous plant growth and resistance to cold. Deficiency symptoms: yellow and brown leaves.
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Iron
deficiency symptoms include chlorosis, death of leaf edges, and stunted growth.
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Chemical Fertilizers
classified by the three major nutrients (N-P-K) which are expressed as a total percentage of weight as packaged. High concentrations of nitrogen in fertilizers can chemically burn the delicate feeder roots of plants. Chemical fertilizers are water soluble, and are often over applied to force plant growth. Excess nutrients washing off of over fertilized lawns and gardens build up in natural drainage systems can throw off the balance between species in downstream aquatic habitats.
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Natural fertilizers
forest litter, compost and manure have much lower concentrations of nutrients, but add organic matter and other beneficial organisms to soil.
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New soil fertility model
Plants are one part of an intricate web of living things that are interrelated, and require dozens of other nutrients and elements that are essential to plant growth such as sulfur, hydrogen, oxygen, carbon, magnesium, and beneficial soil organisms. It is better to use plants adapted to local conditions of soil, drainage, and micro climate than to make extraordinary efforts to compensate for local conditions.
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Cation Exchange Capacity (CEC)
the cation exchange capacity (CEC) of a soil is an indicator of soil fertility. A higher CEC is generally an indicator that the soil is more “fertile” in that exchangeable ionic nutrients are more available to plants
In general, soils with higher clay content or good amounts of organic matter have high CEC. Soil CEC also generally increases as pH increases. Sandy soils typically have low CEC due to nutrient leaching.
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The exchangeable cations of most importance in soil are
• Calcium (Ca2+),
• Magnesium (Mg2+),
• Sodium (Na+),
• Potassium (K+),
• Ammonia (NH4+)
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Soil Amendments and Treatments
* Acid Soils: Add lime to neutralize, or calcium nitrate (a nitrogen fertilizer)
* Alkaline Soils: Add sulfur, or Calcium Sulfate to release alkaline compounds from soil so that they may leach out. Areas irrigated with reclaimed water have a tendency to become more alkaline.
* Nutrient Deficiency: Add commercial/organic fertilizer, manure, compost or leaf mold
* Humus Deficiency: Add organic fertilizer, manure, compost, leaf mold
* Heavy Soils: Add manure, compost, gypsum (for clay) or add a thick layer of deciduous tree and shrub chips.
* Gypsum: Gypsum can improve heavy clay soil structure and remove sodium from saline soils. Gypsum has no effect on soil fertility, structure, or pH of other soil types.
* Compaction: Loosen soil or aerate.
* Slow Drainage: Install drain lines, bore through hardpans. Poorly drained subsoils tend to be blue to gray in color which indicates low oxygen in the soil. Well drained soils are more oxidized and are red, to tan in color.
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Six principles to manage healthy soil.
* Enhance organic matter.
* Avoid excessive tillage.
* Manage pests and nutrients efficiently.
* Prevent soil compaction.
* Keep the ground covered with vegetation or mulch.:
* Increase plant species diversity or rotate crops.
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Types of Erosion Caused by Water
* Splash erosion (usually by rainfall)
* Sheet erosion
* Rill and gully erosion
* Stream and channel erosion
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Factors Influencing Erosion
* Soil Characteristics
* Slope Length and Gradient
* Erosive Forces Present (rainfall, wind, solar)
* Vegetative Cover
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Soil Erodibility
affected by:
• Average particle size
• Gradation
• Percentage organic content
• Textural classifications (see page on soil texture)
• Soil infiltration rates and permeability (i.e. a sand allows greater infiltration and therefore produces less runoff than a clay soil)
• Vegetative cover: holds soil, protects surface, slows runoff, maintains the soils capacity to absorb water
• Topography: slope length, gradient influence runoff velocity and volume
• Climate: frequency, duration and intensity of rainfall; wind effects; solar effects
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Universal Soil Loss Equation
used to predict long-term annual rates of erosion based on rainfall, soil type, topography, crop system, and management practices.
```
A = R x K x LS x C x P
A = estimated average soil loss in tons per acre per year R = rainfall-runoff erosivity factor K = soil erodibility factor L = slope length factor S = slope steepness factor C = cover-management factor P = support practice factor
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Landslide Prevention and Correction -Excavation
* Removal of unstable material
* Flattening of slopes
* Benching of slopes
* Lightweight fill
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Landslide Prevention and Correction -Drainage
* Slope treatment for faster runoff
* Surface ditches
* Sealing joints, planes, and fissures
* Subdrainage to relieve hydrostatic pressure
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Landslide Prevention and Correction -Restraining structures
* retaining walls
* buttresses
* rock fill
* reinforced earth
* shotcrete (gunite)
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Landslide Prevention and Correction -Flexible reinforcements
* using geotextiles and geogrids
* using soil nailing - This is a modern variation on dead men in retaining walls. Holes are bored into an unstable slope and filled with steel and concrete
* Pilings
* rock bolts: similar to soil nails, but embedded into fractured rock faces.
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Landslide Prevention and Correction -Vegetation
* hydroseeding
| * forestation
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Igneous Rocks
classified based on their mineral composition and grain-size, which is a result of the cooling rate of the parent magma. Igneous rocks fall into two sub-categories:
• Extrusive rocks cooled quickly when brought to the surface by volcanic eruption. The grains in the rocks tend to be fine. Common examples include Basalt and Gabbro.
• Intrusive rocks cooled more slowly within the earth. The rocks grains are coarse, easily seem with the naked eye. Common examples include Granite and Rhyolite.
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Sedimentary Rocks
classified based on their depositional mode.
• Mechanically eroded and precipitated rocks include Conglomerate, which has some particles that are gravel sized, Sandstone which has sand size particles, and Shale and Siltstone in which the particles are in the silt to clay size range.
• Chemically precipitated rocks include Limestone, which is primarily calcium carbonate, and Chert which contains quartz crystals and is harder than limestone.
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Metamorphic Rocks
classified based on composition and texture.
• Foliated metamorphic rocks exhibit a distinctive layering. Examples include Gneiss, Schist, and Slate.
• Non-foliated metamorphic rocks include Quartzite, which results from the deformation of sandstone and Marble, which results from the deformation of limestone.
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Geomorphic Processes
Processes that make or alter landforms.
• Tectonic
• Fluvial: erosion, transportation, and sedimentation from rivers and streams.
• Aeolian: erosion , transportation, and deposition by wind.
• Mass Wasting: movement by gravitational forces - landslide.
• Glacial
• Weathering
Mechanical: wind, frost
Chemical: oxidation, carbonation. hydrolysis, hydration
• Volcanic
• Biological: root penetration, litter deposition and biochemical action
• Wave Action
Littoral Drift (movement of sand along a coastline due to wave and tidal action)
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Aquifer
an underground reservoir that can be accessed with drilled wells
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Artesian Well
underground pressure forces water up to the surface of the ground through manmade well or a naturally occurring channel
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Karst
barren rocky ground with many sinkholes and underground streams
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Moraine
glacial landform created when ice retreats, leaving the soil it was pushing as a mound. Also called glacial till
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Strata
layers of soil and rock
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Vadose Zone
a layer under the surface where the soil pores contain a mixture of air and water.
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Littoral Zone
the area between the high and low tide lines along coasts, estuaries and bays. Generally subject to wave action and periodic inundation.
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Expansive Soils
soils that swell in volume when they are wetted and shrink when they dry out. Such soils may cause sidewalks to crack, foundations to crack or fail, basement walls to fail, and retaining walls to fail.
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Plasticity Index
widely used for assessing the shrink-swell potential of soil. Soils with a PI greater than 20 are considered expansive. Greater than 40 is considered highly expansive. The Plasticity Index is the difference between the Plastic Limit and the Liquid Limit of a soil. The plastic limit is the point where the soil is moist enough to deform under pressure without returning to its shape (like modeling clay). The liquid limit is where the soil behavior changes from plastic to liquid (like quicksand).
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Liquefaction
Soil liquefaction occurs when a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress such as shaking during an earthquake or other sudden change in stress condition, in which material that is ordinarily a solid behaves like a liquid.
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Soil Color
A blue or gray color in soil is usually due to poor drainage (lack of air in soil).
Yellows and reds indicate good drainage (plenty of air). These are usually caused by iron oxides.
Dark colors in surface layers are usually caused by the presence of organic matter.
Light colors in the upper soil layers are often due to nutrient and iron leaching due to high percolation rates. High levels of calcium carbonates also create light colors.
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Environmental Site Assessments
evaluations of risk for conditions of possible environmental contamination. Under federal law, a landowner is liable for environmental conditions on his property whether they had any knowledge of the contamination or not, or was involved in the contamination. Liability can include cost of cleanup and damages to third parties. Buyers or lending agents minimize this risk by engaging environmental professionals to conduct these ESAs in advance of purchasing property.
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Transaction Screen (or environmental screening)
1. Has the site been filled in the past?
2. Knowledge of hazardous materials or petroleum products in fill?
3. In area currently or historically used for industrial or commercial activities?
4. Zoned for commercial or industrial uses?
5. Adjacent properties zoned for commercial or industrial uses?
6. Evidence of present or past use or storage of hazardous materials?
7. Adjacent properties drain on to the site?
8. Reasons to suspect the quality of runoff from adjacent sites?
9. Presence of electrical transformers?
10. Is an on-site well used for the sites water supply?
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Phase 1 Environmental Assessment
more intensive level of assessment of contamination hazard and should be conducted by a qualified environmental professional.
1. Site condition
2. Applicable zoning regulations
3. Land development regulations
4. Utility access
5. Traffic
6. Topography
7. Soils/geology
8. Hydrology
9. Vegetation/Wildlife
10. Historic or cultural features
11. Existing public space
12. Environmental hazard concerns
13. Review of existing records
14. Sources used to determine the history of the site
15. On site walkthrough
16. Interviews
17. Conclusions and recommendations
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Phase II Environmental Assessment
involves the taking and analysis of samples to confirm contamination of a site that was suspected during the Phase I assessment.
Samples could include soil, suspect liquids found on site, or groundwater samples, among others.
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Environmental Impact Review
Generally applies to substantive projects such as planned unit developments (PUDs), shopping centers, large subdivisions, significant governmental projects, or projects which may impact sensitive natural habitats. Almost any project triggering a review by a federal agency (the Army Corps of Engineers, for example) would be required to file some sort of environmental impact report.
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Archeological Resources and Historic Properties Review
When archeological resources are discovered on the site
Regulated by State Archeological and Local Planning Staff
When Historic Properties are to be impacted
Historic Properties regulated by Local Planning Staff and Landmark Commissions
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Design Review/Planning Review
Virtually all buildings, especially commercial or industrial uses. Increasingly applied to single family houses. Regulated by Local Planning Staff and Planning Boards or Architectural/Design Review Boards, Early in the process and usually concerned with aesthetics and zoning code compliance
- Parking
- Fence height and location
- Signage
- Tree removal and replacement
- Architectural style (does it fit with surrounding neighborhood)
- Site emergency access and egress
- Stormwater filtration
- Confirms setbacks/easement/density requirements
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DU: Dwelling unit
DU/acre
In small towns and typical subdivisions in America the densities range from 4 to 5 dwelling units per acre for detached single family housing.
Duplexes and cluster housing achieves 6 to 8 units per acre.
In an urban zoning district, these numbers will be much higher – 30 DU/acre or more
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Floor area ratios (FAR)
a flexible way to regulate density. Build up instead of out
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Storm Water Pollution Prevention Plan
Required by Federal EPA (National Pollutant Discharage Elimination System).
In order to get a SWPPP permit, the team must submit the following and maintain during construction.
- Plan showing proposed BMPs (sedimentation/erosion control, Good Housekeeping measures like construction entry, tire cleaning/tool cleaning areas, spoils reservoir for leftover chemicals/paint)
- Permit binder with copies of all the project and permit documentation, including maintenance and inspection schedules and procedures
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Building Permits
For new building construction or renovation
Regulated by Local Building Officials
Issued after planning and development related reviews are completed
Issued just prior to the beginning of construction
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Occupancy Permits
Required to occupy Commercial, Industrial, or Multi-Family Residential structures
Regulated by Local Planning and Building Staff
Issued after all identified code issues have been resolved during the construction process
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Appeals
Made to a higher authority to seek to overturn a decision
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Accessibility Regulations and ADA: The Americans with Disabilities Act
Sets national standards for access to buildings, facilities, parks, etc. The act covers items such as for handicapped accessible parking spaces at facilities of all kinds; curb ramps on sidewalks; ramps, steps and handrails inside and outside buildings and in public open space; overhead clearance, cross slopes and slip resistance on public sidewalks, etc.
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ADA Technical Items Specific to Landscape Architecture
* Quantity, location and dimensions of accessible parking spaces in parking lots
* Accessible space markings and signage
* Allowable grades (including cross-slopes) on accessible paths of travel
* Curb ramp locations, geometry and slopes
* Warning devices, such as texture changes, contrasting colors, or audio signals
* Special operating devices for elevators, doors, or signal lights
* Minimum allowable widths and vertical clearances on accessible paths of travel
* Equivalent access and usage features for the disabled to public facilities
* Allowable slopes on ramps, maximum change of grade between landings
* Standards for landings at doorways, for ramps at the top, bottom and middle
* Allowable stair tread and riser dimensions
* Handrail grip surface dimensions, mounting heights, and clearance from walls
* Handrail projections at landings and at top and bottom of ramps and stairs
* Maximum threshold heights
* Door hardware dimensions, mounting and operational standards
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Agricultural and Rural Landscape Analysis -Economic Issues
* Competing uses for fertile undeveloped lands, long-term farming or conservation often cannot compete with short-term profits in developing rural landscapes
* Societal stake in protecting productive agricultural lands or undeveloped greenbelts
* Costs of extending civic services/infrastructure vs. changes to tax base
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Agricultural and Rural Landscape Analysis -Cultural Issues
* Preserving traditional/rural societies as a regional resource
* Use conflicts between housing and farming (smells, traffic, etc)
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Agricultural and Rural Landscape Analysis -Tools for Managing Rural Landscapes
* Agricultural or rural trusts, purchase or transfer of development rights
* Zoning and other Planning Codes
* Cluster Housing: Housing units are located in close proximity to each other and share common open space, which may include agricultural preservation areas.
* Urban Growth Boundary: A regional boundary, set in an attempt to control urban sprawl by mandating that the land inside the boundary be used for higher density urban development. Area outside the boundary is to be used for lower density development.
* Prime Agricultural Soils: Soils that are considered ideal for agricultural production which should remain in agricultural use.
* Agricultural Suitability: An assessment of the availability of water supply, favorably productive soil conditions, and climatic factors that combine to create conditions considered critical for highly productive agricultural (cropland) land.
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Greenfield
A previously undeveloped parcel currently in agricultural, forest, or natural state.
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Greyfield
A previously developed parcel that has no history of environmental contamination or minimal contamination. Development of greyfields is more sustainable than urbanization or suburbanization of previously undeveloped land. There would be less degradation of natural resources, reduced urban sprawl and increased urban density.
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Brownfield
A previously developed parcel that has a history of environmental contamination, where the presence or possible presence of a contaminant, pollutant or hazardous substance may complicate reuse. Some considerations when undertaking brownfield development include liability protection, cleanup standards, risk management, and mitigation strategies. The EPA administers a Brownfield Program in the US to encourage cleanup of these sites.
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Urban Landscape Analysis
Some purposes of this type of analysis include:
• Create maps of urban density or land uses
• Identify changed infrastructure requirements
• Determine location suitability for infill development
• Map boundaries of development/neighborhood types
• Identify development trends based on historical growth patterns
• Map urban heat islands and develop mitigation recommendations
• Create maps of general categories of land use (eg. buildings, pavement, landscaped, agricultural, undisturbed)
• Map microclimates
• Assess movement and circulation linkages
• Characterize open space and built form character
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Interpret Social Analysis
Based on what you have learned about demographics, likely user groups, and future trends, does the program need to be adjusted?
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Interpret Economic Analysis
Much of these types of analyses may be performed during site selection and/or program development of a conceptual program for a project.
• Pro Forma: financial forecast based on hypothetical, anticipated profits and losses
• Cost / Benefit Analysis
• Market Performance: demand, relationships of uses, absorption (rate of sale)
• Public Financing: roads, infrastructure, maintenance, insurance, financial return
• Legal Concerns: Spatial, Zoning, Deed Restrictions
• Land Development Costs: clearing, grading
• Demographic trends and anticipated future demand
• Cluster Analysis: diagram showing relationships and linkages. Note: this is different than Cluster Development! Cluster Analysis is similar to the kind of data sorting we discussed for GIS, except it is concerned with economic factors. ‘K-means’ refers to the method for sorting the data by an average value (a mean) that is determined to be the center of each cluster.
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Building Envelope Studies
diagramming showing political governmental restrictions such as setback and zoning regulations. The total space (volume) available for structure when all these factors are taken into account is sometimes known as the building envelope.
This is a spatial analysis tool, obviously, but it is also a financial analysis. For the given development budget, what will the cost per square foot be, and what will the anticipated ROI be (return on investment)?
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Analyze Contextual Data
What is happening around the site? Questions we might ask:
• Are there program elements that are incompatible with adjacent land uses?
• Are there program elements that should take advantage of topography and orientation for views out from the project?
• Which program elements need to be screened from others or from adjacent land uses?
• What existing features on the site impact the placement of program elements?
• Are some program elements incompatible or less compatible with other program elements?
• What program elements should be placed adjacent to one another?
• How does the arrangement of the program elements impact internal circulation?
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Analyze Stakeholder Feedback
Technical Committees: may include City staff, organizations that will be servicing the project like trash, public transit, social workers, docents.
Specialists and Advisors: Historians, local Chamber of Commerce, organized interest groups like bicycle advocacy, neighborhood watch, etc. provide advisory context. This group will need to be managed carefully so no one perspective dominates the project, but all have a chance to inform and participate in the process.
General Public: While a big part of outreach to the public is aimed at keeping them informed, for many projects you can gain valuable insight into activities and amenities that will be most valued. In extreme cases, if there is strong, organized public opposition to a project, the team should discuss finding ways to negotiate or reassure the public in order to avoid a long, drawn-out battle that may result in a failed project.
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INVENTORY
Inventory and data gathering is an essential step in determining a site's physical, biological, and cultural attributes (physical and non-physical). Area of investigation extends from the site to the surrounding landscape or context. The findings serve as a basis for analysis and ultimately for final site programming and design.
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Corporate Power
the authority to collect revenues (from bonds, fees, taxes, and assessments) and to spend these monies to provide services and facilities (such as roads, water and sewage facilities, parks, etc.).
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Police Power
the authority to regulate citizen behavior (including the use of private property) in order to promote the health, safety, and welfare of the public.
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Comprehensive Plans
A Comprehensive Plan has four Basic Characteristics:
• Physical: It is a guide to the physical development of the community.
• Long Range: It covers time periods of 5 years or longer.
• Comprehensive: It covers the entire city or county geographically.
• Statement of Policy: It assesses and describes community desires relating to land use and how they are to be achieved.
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Elements of Comprehensive Plans
* A Land Use Element which designates the proposed general distribution, location and extent of the uses of land.
* A Transportation Element describing existing and proposed major thoroughfares, transportation routes, terminals, and other local public utilities and facilities.
* A Community Facilities Element describing utilities and parks and open space
* A Housing Element.
* An Economic Development Element.
* A Critical and Sensitive Areas Element for the conservation, development, and utilization of natural resources including the reclamation of land and waters, water pollution control, erosion control, watershed protection, flood control, and the location, quantity and quality of rock, sand and gravel resources.
* A Natural Hazards Element for protection from unreasonable risks from earthquakes, tidal waves, dam failure, landslides, other geologic hazards, flooding, and wildland and urban fires.
* An Agricultural Lands Element.
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Regional and Neighborhood Plans
* Regional plans are large in scale and can include several cities and even cross state lines.
* Neighborhood plans are usually smaller in scale and relate to a part of a city. “Development at a scale greater than household size but smaller than a city”.
must include the following information:
• Distribution, location, and extent of land uses, including open space, within the plan area
• The proposed distribution, location, and intensity of major components of public and private transportation, sewage, water, drainage, waste disposal, and other essential facilities proposed within the area covered by the plan and needed to support the land uses described in the plan.
• Standards and criteria by which development will proceed, and standards for the conservation, development, and utilization of natural resources.
• A program of implementation measures including regulation, programs, public works projects, and financing measures.
• A statement of the relationship of the Regional or Neighborhood Plan to the adopted local Comprehensive Plans. The government’s authority to exercise police power must be clearly described and traced back to specific legislation.
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Zoning Ordinances
Zoning ordinances are intended to accomplish the following items:
• Regulate the use of buildings, structures, and land between industry, business, residences, open space, agriculture, recreation, scenic beauty, use of natural resources, and other purposes.
• Regulate signs and billboards.
• Regulate all of the following:
The location, height, bulk, number of stories, and size of buildings and fences.
The size and use of lots, yards, courts, and other open spaces.
The percentage of a lot which may be occupied by a building or structure.
The intensity of land use.
Establish requirements for off-street parking and loading.
Establish and maintain building setback lines.
Create civic districts around civic centers, public parks, public buildings, or public grounds, and establish regulations for those civic districts.
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Subdivision Regulations
Specific standards dictated by subdivision regulations may include:
• Lot shape and minimum lot size.
• Road rights-of-way dimensions, layout and construction standards.
• Types and widths of easements for utilities and access ways.
• Construction standards for the provision of water, sewerage, power, drainage systems, and other common infrastructure.
• Open space requirements, such as dedication of land for parks.
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Easements
Easements grant an affirmative right to use another person’s land for a specific purpose. Easements automatically continue to apply to a parcel of land even if the property changes ownership. The easement may restrict use of the land within the easement by the property owner if such use interferes with the use of the easement grantee.
Enforcement: By the party benefited by the easement.
Examples: Drainage easements, utility easements, access easements, conservation easements, view easements
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Covenants
Formal binding agreement. Covenants may be either restrictive or affirmative.
• A restrictive covenant is a restriction on the right to use land that applies to the owner of the property.
• An affirmative covenant is where the property owner agrees to take certain actions that benefit other parties (usually on adjacent parcels).
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Using Assessor’s Office Information as Inventory Data
Information contained on these maps includes:
• Lot line locations and dimensions
• Lot numbers
• Road and street rights of way
• Street names
• Utility and other easements
On site, you can look for clues:
• Stakes set by previous survey teams at property cornes
• Built elements that line up across properties, possibly showing where setbacks or property lines are approximately located
• Utility vaults or manholes that may indicate an easement running through the property
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Municipal Codes
* Building Code
* Plumbing Code
* Mechanical Code
* Electrical Code
* Fire Code
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Building Codes
apply to the construction, erection, enlargement, alteration, repair, moving, improvement, removing, conversion, demolition, and use and occupancy of all buildings and structures.
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For Landscape Architects, Building Codes typically set standards for the design and construction of:
* Walls and Steps
* Decks, Patios and Walkways
* Swimming Pools and Spas
* Fences, Arbors and Trellises
* Drainage Systems and Structures
* Fountains and Water Features
* Irrigation Systems
* Site Lighting
* Vehicular and Pedestrian Circulation Systems
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Appurtenance
Additional rights which goes with or pertains to the land, but is not necessarily a part of it. Examples include a right of way or a building. Appurtenances go with the land when it is sold.
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Affordable Housing
rental or owner-occupied housing that costs no more than 30 percent of a household’s total monthly income.
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Annexation
is the process in which an unincorporated area joins an adjacent city.
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Board of Adjustment
Considers variances to planning ordinances for specific developments.
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Buffer Zone
Land or water designated to separate one use from another. e.g., to shield or block noise, light or other nuisances.
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Cluster Development
The grouping of a particular development's residential structures on a portion of the available land, reserving a significant amount of the site as protected open space.
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Complete Streets
streets designed and operated to enable safe access for all users, including pedestrians, bicyclists, motor vehicle drivers and transit riders of all ages and abilities. Complete Streets make it easy to cross the street, walk to shops, and bicycle to work.
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Concurrency
the term that needed services be in place or planned for before new development is approved. Also referred to as Phased Development Controls.
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Eminent Domain
he taking (with due compensation) of private land by a government agency for the public good.
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Encroachment
An unauthorized invasion or intrusion of a fixture or other real property on another's property. Often permits are issued for temporary encroachments for construction purposes. For example, the use of City sidewalks and parking spaces on streets for site access, storage of materials, scaffolding, etc.
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Extractive Use
Land including accessory buildings and structures used for the removal, refinement and/or processing of sand, gravel, stone, mineral, or other aggregate resources. E.g., a soil borrow pit, a gravel pit and a stone quarry.
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FEMA
Federal Emergency Management Agency -- Maps and sets national standards for development in flood prone areas.
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Flag Lot
A lot which has a narrow access strip connected to a public street or right-of-way. The strip contains the driveway.
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Frontage
A linear measurement along the front of a property, that is, the portion facing a road, waterway, etc.
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Greenhouse Gas Emissions Plans (GHG plans)
Through planning and building requirements and outreach grants, these plans are aimed at reducing greenhouse gas emissions due to petroleum-burning vehicles, and lighting and building energy inefficiencies. These plans use a variety of tools to try to reduce car trips, like bicycle route and multi-modal transportation networks, urban greening through tree planting in underserved neighborhoods, and stricter standards for energy efficiency.
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Greenbelt
A band of countryside surrounding a town, development or neighborhood on which building is generally prohibited.
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Gross Floor Area
Total floor area contained within a building including the horizontal area of external walls.
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Inclusionary Zoning
refers to regulations that increase housing choice by establishing requirements and providing incentives for constructing a wide variety of housing types.
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Infill
means developing smaller vacant parcels of land in urban areas that have been passed over by previous development.
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Infrastructure
means the basic facilities serve a community, such as streets and highways, schools, and water, sewer, and storm drainage systems.
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NEPA - National Environmental Policy Act of 1970
Established policy for clean air, water, and the protection of natural resources.
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Net Floor Area
The total square footage of occupied area of a building.
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Non-Conforming Use
Any use which does not conform to the use regulations of the Zoning Ordinance for the zone in which it is located.
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Occupancy
As used in the Building Codes, occupancy refers to the type of use of the building. For example, a Residential Apartment Building vs a Medical Care Facility.
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Planned Unit Development
A development which contains a mix of land uses, various types of residential uses, commercial uses and institutional uses. Occasionally industrial uses are included.
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Ordinances
laws passed by a local government which support the General or Comprehensive Plan.
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Real Property
Land and its permanently affixed buildings or structures.
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Restrictive Covenant
An agreement restricting the use of real property which is attached to the conveyance (deed) and which is binding on subsequent purchasers of the property.
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Right-of-Way
a strip of land occupied or intended to be occupied by a street, crosswalk, railroad, electric transmission line, oil or gas pipeline, water main, sanitary or storm sewer main, shade trees, or other special use.
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Riparian Rights
The right of an owner to the use and enjoyment of water which flows across or along his land. It includes a right of an owner of land abutting a body of water to make use of the water area for piers, boat houses, for fishing, boating and navigation, and the right of access for such purposes. Note: Western states water use rights do not generally go with the land.
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Setback
a required minimum horizontal distance between a structure and the related front, side, or rear property line.
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Variance
A means to allow an applicant for a development permit to alleviate a hardship that is inherent in a piece of land.
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Collect Contextual Data
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Most of these are what we would have called Cultural Factors in the past.
• Adjacent Land Uses
• Public Infrastructure
• Typical Scale/Style/Density of surrounding buildings
• Historic Resources
• Archeological Resources
• Noise, Odors, and Visual Quality
• Potential Hazards
```
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Population Density and Distribution
* US Census Bureau: Census Tract Data
* Public Health Department
* State, county, and local planning agencies
* Utility companies
* Crime statistics
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Urban Form
Plat maps for entire assessor’s tracts
• Zoning maps (available online through the municipal planning department in urban areas)
• Satellite imagery or aerial photography (Google Earth began in 2001)
• City Map / Road Map
• Figure Ground Drawing: A map showing building vs open space. Roads are not shown
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Where to look for data on Streets, Highways, Traffic, Parking
* Police Department accident files
* Other Transportation Agencies
* Parking Counts
* Traffic Counts, Traffic Modeling (done by a traffic consultant)
* Public Transit maps – busses, subway, light rail, bicycle routes, Master Plans produced by cities (includes a current inventory and goals)
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Where to look for data on Infrastructure
* Local Department of Public Works databases
* Site Surveys
* Historical or Archeological Surveys
* Sanborn Insurance Maps- found at city libraries and archives, microfiche
* Historic USGS or other maps
* Utility Company and Utility Agency Mapping
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Where to look for data on Tax and Land Value
* Assessor’s public database, searchable by APN (Assessor’s Parcel Number)
* Lincoln Institute of Land Policy (price indexes for land and structures)
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Seismic Hazard Maps
Shows the potential for earthquakes in different areas.(USGS) – include some topo, but not adequate for design
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U.S. Geologic Survey (USGS) or City engineering maps
* Produced from aerial photos
* Control points set with ground surveying
* Not accurate enough for site work
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Site Survey
* Property lines with bearings and distances
* Easements
* Visible utility structures
* Benchmark
* Spot elevations at building corners and hardscape features
* Floor elevations
* Spot elevations at the base of large trees
* Tree diameters
* Fences, walls, and other constructed site features
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Field Survey
* Produced by surveyors on the ground using transits or digital theodolites
* Client instructs survey crew on critical elements to map and degree of accuracy required
* Common contour intervals from 1’ to 10’
* Elevations and horizontal measurements accurate to 1/100th of a foot (for hardscape elements)
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Aerial Survey
* Produced from orthophotographic pictures
* A few critical control points verified via ground survey
* Scale and contour interval can vary
* Accuracy not as good as a field survey
* Not as suitable for detailed site work as a field survey
* Site features that occur under tree canopies will not be mapped
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LIDAR Survey
* Produced by a ground crew using a pole-mounted or drone-mounted LIDAR sensor
* Does not require clear lines of sight
* Can pick up excellent ground contours, outlines of structures and major tree locations
* Will not pick up flat hardscape surfaces or pavements
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Angle Of Repose
The angle of repose is the maximum angle of a stable slope determined by friction, cohesion, and particle shape. It is described as the angle between a sloped surface and a hypothetical level plane below. A high angle of repose is steeper than a low angle of repose.
Typical soils, sands and gravels have angles of repose between 25-45 degrees. Wet clays however lose cohesion when saturated and the angle of repose can go as low as 15 degrees.
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Vegetation Survey
* Aerial Photos, especially infrared for forest studies
* Multispectral Scanning (visible and invisible electromagnetic)
* Published ecozone systems like Sunset, Perry
* USDA Hardiness Zones
* US Fish and Wildlife Service: National Wetlands Inventory
* Local Mapping, especially City street tree master plans if they exist
* Site Survey showing tree locations, diameter
* Field Verification
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Soil Survey
* Soil Fertility Report (Agricultural Suitability, soil texture and NPK etc numbers)
* Soil Microbiome Testing (levels of fungal, bacterial, and microorganisms in the soil)
* USDA Soil Survey maps
* Geotechnical Reports (site or project specific)
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Geological Survey
* Geologic Maps (USGS and State Geologists)
* National Park Service Geologic Mapping and Reports
* University Geologic Map Libraries
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Assessing Site Risks - Flooding
Consult historical records, FEMA maps, other topo surveys to establish areas prone to flooding. Walking the site will often also reveal evidence, including water damage on structures, earthform that has been shaped into benches, and the presence of special plants.
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Assessing Site Risks - Fire
based on natural and cultural features:
• Degree of development.
• Fuel loading (type and condition of vegetative cover, forest/understory structure)
• Seasonal weather patterns – rain, wind.
• Slope. Steep slopes are much higher risk due to wind acceleration and also much harder to access for fire crews.
• Aspect. Slopes that are dry, due to southern or western exposure, or that are exposed to heavy dry winds, are high risk, especially if assets are found upslope.
• Accessibility to fire protection assistance (i.e., response time, availability of helispots, proximity of air tanker attack bases, availability of woods workers, etc.).
• Proximity to communities or assets at risk.
• Historic fire data. State agencies keep detailed records of burn dates and areas.
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Types of Landslides
* Falls: Rocks falling or rolling off ledge or slope
* Rock Slump: concave surface, material moves along identifiable surface
* Lateral Spread: fractured masses move laterally
* Debris Flow: material moves as liquid, often saturated with water
* Soil Creep: slow imperceptible movements
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Factors that Contribute to Landslides
* Accelerated erosion
* Undercutting: streams, road cuts
* Surcharge of weight: water, snow, buildings, fill
* Uplifting and tilting: Earthquake, plate tectonics
* Mechanical cut and fill
* Deforestation
* Improper siting and construction
* Earthquakes
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Estimation of Landslide Hazards – clues to look for on site
* Angle of repose – has the hillside been cut back, or is it in its natural slope?
* Type of material: most hazardous is loose granular materials
* Angle of parent material (bedrock) to slope
* Seepage of water along hill
* Colluvial soils: indicates past history of slides
* History of slope activity (recent slides)
* Structural Damage – cracks in walls and foundations
* Hummocky Topography (characterized by small mounds and depressions)
* Scarps and Cracks
* Incongruent Vegetation: Patches of Younger, Very Different Vegetation
* Broken Trees (pistol handled, jackstrawed)
* Bedding Planes Dipping Down Slope
* Accumulation of Debris At Toe of Slope
* Light Tones Along Upper Edges of Stone Cliffs
* Changes in drainage patterns from upslope neighbors
* Undercutting (streams, highways)
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Cultural Hazards
* Toxic waste
* Air pollution
* Polluted ground water or surface water
* Unstable fill
* Flooding due to increased impervious area or restricted channels
* Brownfields - Previously developed or mined areas which may be contaminated with pollutants.
* Greyfields - Previously developed urban land
* Sanitary Landfill Sites
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Primary Data Collection
* Interviews
* Observation: windshield survey, transect, etc.
* Visit site and similar locations
* Other specialized field techniques
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Site Visit Data Collection
* Views
* Tree species identification and assessment of tree or vegetation health
* Identifying safe access points to the site
* Verifying the presence of unstable or poorly drained soils
* Identifying the presence of or rough limits of wetlands
* Evidence of shallow bedrock in some locations
* Individual details of hardscape conditions that may not show up on a survey
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Document Site Inventory
* Base Map (Existing Conditions Plan, Survey, usually site scale)
* GIS Data Sets (Usually more regional in scale, used for McHargian analysis)
* Various Technical Reports (you may have a Geotech report, a Chain of Title report, Traffic Studies, Historic Assessment Report or others.
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Base Maps
* Legal conditions: property lines, easements, other
* Topography: contour lines, significant spot elevations
* Existing buildings, other structures to remain
* Proposed structures
* Existing and proposed hardscape (sidewalks, driveways, etc.)
* Significant subsurface features – underground lines, common trenches
* Utility poles, boxes
* Existing trees to remain
* Other significant site features that should be protected – drainage swales, any areas to be off limits for wildlife, vegetation, or cultural protection
* If there is a common layout structure that provides coordination between the trades, that may be shown as well, ie. coordinate grid systems, station points or benchmarks.
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Site Analysis
a program driven assessment of a site’s physical, biological and cultural attributes. In a general sense, a site analysis involves the determination of the areas of the site that are suitable for placement of the various parts of the development program. This is done after accumulation of background data through the Inventory process.
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Site Constraints
* Inappropriate
* More complex to design and construct (physical constraints to implementing program)
* Difficult to gain necessary approvals (legal constraints)
* Difficult to maintain
* Health and safety concerns (fire, landslide hazards, etc.)
* Site access issues
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Site Opportunities
Assets that have social, economic, ecological and aesthetic value, or favorable adjacencies
• Unique rock outcrops
• Historic or culturally significant buildings
• Scenic overlooks and views
• Water features
• Vegetative communities
• Proximity to public transit
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Site Development Capacity
* Is the program compatible with long range community needs?
* Will the program fit on the site?
* Does sufficient infrastructure exist to support the proposed program?
* What are potential economic, social and environmental costs to the community?
* Is the program likely to encounter serious opposition from within the community?
* Should the site remain “undeveloped”?
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Suitability Analysis
the process of determining the fitness or appropriateness of a given tract of land for a specified use
* Identify optimal locations for specific site activities or function (site planning)
* Identify sites that are suitable for specific land uses that involve minimal additional inputs (site selection)
According to LaGro, a suitability analysis involves three steps:
• Identify suitability criteria for each anticipated land use
• Collect and map the relevant site attribute data
• Identify the site locations with attribute values that meet the suitability criteria for the programmed land uses.
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Circulation analysis
* Based on current inventory, is the available street network adequate to support the project?
* What are available mass transit options?
* What are likely bicycle and pedestrian needs?
* What is the impact on parking demand?
* Are existing circulation systems in good repair?
* What are the best access points to the site in terms of safety and impact on the adjacent streets?
* What impact do on site natural resources have to constrain potential access points due to reasons of economics, aesthetics or environmental impact?
* What are the expectations of site users for the internal circulation and access?
* Do the planned layouts for buildings and amenities allow enough room for fire and garbage access?
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Utility Analysis
* Are the available utility resources adequate to support the project?
* What upgrades may be needed? What are their costs?
* Do utility easements or corridors (existing or proposed) impact the site design?
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Visual Resource Analysis
Objectives
• Identify impacts on the existing visual resource
• Establish the relationship of those impacts to potential viewers of and from the project
• Describe measures to avoid, minimize or reduce adverse impacts
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USBLM Visual Resource Classes
Class I Objective: To preserve the existing character of the landscape. The level of change to the characteristic landscape should be very low and must not attract attention.
Class II Objective: To retain the existing character of the landscape. The level of change to the characteristic landscape should be low
Class III Objective: To partially retain the existing character of the landscape. The level of change to the characteristic landscape should be moderate.
Class IV Objective: To provide for management activities which require major modification of the existing character of the landscape. The level of change to the characteristic landscape can be high.
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Macroclimatic Factors
* Temperature range – annual extremes, especially frost
* Humidity
* Wind – direction, seasonality, velocity
* Annual rainfall and temporal distribution
* Snowfall – annual maximum depths and dates
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Microclimate Factors
Western Slopes hottest in summer
Southern Slopes receive most sun in winter
Southeastern slopes most desirable climate
Northwestern slopes receive cold winter wind
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Solar Radiation at the site scale
• Surface Temperatures
• Vegetation Changes seasonally
• Ventilation effects of wind
• Fog and Frost Frequency and Location
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Microclimates
smaller area within a general climate zone that has its own unique climate. An area as small as a yard or park can have several different microclimates depending on how much sunlight, shade, or exposure to the wind there is at a particular spot
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Site Analysis and Design Response to Modifying Microclimates
* On urban sites, do shadows from tall buildings affect solar access?
* In downtown areas, are there wind tunnel effects that impact the site?
* Are there areas on the site that are susceptible to frost?
* Is the site in a fog-prone area?
* Coastal sites are more frequently exposed to wind than inland sites.
* Coastal sites have salty air which can impact materials choices, particularly metals.
* Higher elevations tend to be cooler (see vertical lapse rate under topography)
* Humidity tends to buffer air temperature changes.
* Due to the normal direction of the jet stream, westerly slopes on higher ridges tend to receive more moisture than slopes further to the east.
* Providing shade and minimizing hardscapes will generally reduce actual and perceived air temperatures in outdoor use areas.
* Small water features may increase humidity.
* Windbreaks can be used to block seasonally hot or cold winds.
* Deciduous trees provide shade in summer but allow solar heating to occur in winter.
* At the site scale, soil chemistry and texture, soil moisture levels, and sun-shade conditions can dramatically affect planting design.
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Sun Angle
The angle formed between sun and the earth’s surface.
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Ground-sun angle
Takes local topography into account.
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Incidence/Insolation
The density of light hitting the surface; amount of radiation per unit area.
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Solar Incidence Angle
The Solar Incidence Angle is the angle between the Sun's rays and an imaginary line perpendicular to the collector's surface. An incidence angle of 0 means the Sun's rays are perpendicular to the collector surface.
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Solar Heating/Solar Gain
solar energy absorbed by a surface
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Albedo
defined as the ratio of total-reflected to incident electromagnetic radiation. It is a unitless measure indicative of a surface's diffuse reflectivity. High reflectivity = high albedo = lower heat gain
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Solar Reflectance Index (SRI)
The Solar Reflectance Index (SRI.) is a more modern measure of a surface’s ability to reject solar heat, as shown by a small temperature rise. It is a combination of surface reflectivity and the ability of a warm or hot material to shed heat in the form of infrared radiation.
low numbers are bad.
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Urban Heat Island Effect
Basic Strategies for Ameliorating Urban Heat Islands
• Light colored roofing materials, roof solar panels, or green roofs
• Use light colored paving materials
• Shade hardscape and buildings with trees, trellises and green walls
• Water has a high heat capacity, thus sizable surface water features act as heat buffers
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Permafrost
soil at or below the freezing point of water (0 °C or 32 °F) for two or more years. Building on permafrost is difficult due to the building (or pipeline) thawing the permafrost with its heat and then sinking.
This problem has three common solutions:
• Using foundations on wood piles, typically 50 feet or more deep as the soil temperature does not change seasonally at this depth.
• Building on a thick gravel pad (usually 3.5-6.5 feet thick)
• Using anhydrous ammonia heat pipes. The Trans-Alaska Pipeline System uses insulated heat pipes to prevent the pipeline from sinking.
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Hydrological Analysis
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Elements of Hydrologic Inventory
• Drainage Basins
• Stream and Wetland Locations
• Flow Volumes (Q, graphically measured in hydrographs)
• Floodplains
• Lake Levels and Tides
• Storm Drain Systems
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Factors that impact Watershed Response to storms
Watershed response to storms is impacted by several factors:
• Topography - the size of the watershed and its relative slope
• Vegetation - type and maturity. Root networks protect banks and slow flows
• Soil type and shallow bedrock
• Amount of impervious surfaces upstream - buildings and pavements are impervious
• Conversion of more pervious surfaces to less pervious ones (eg. forest to lawn)
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Peak Flows
Increase due to increased runoff
This makes downstream pipes and channels inadequate to carry streamflows
Volume of Runoff Increases due to increased runoff
Conversely, baseflow levels and groundwater/aquifer recharge levels decline
Time to Peak Decreases due to smoother watershed surfaces
Water moves through the watersheds at a faster rate
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Channel Erosion
Increases
The channel tries to widen and deepen itself in order to accommodate the additional runoff. To protect adjacent structures, it then becomes necessary to armor the banks and the bottom of the channel. This causes downstream sedimentation. The erosion products are dumped at or below these transition points, which may create the need to continue the "improvements" further downstream.
Channel erosion also causes riparian vegetation to be undermined and fall into the channel.
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Flood High Water Levels and Frequency of Flooding
Increase
Flooding occurs when too much water tries to pass through some bottleneck in the drainage system - a pipe that is too small, a bridge, or a partial blockage due to debris in the channel. Naturally as a watershed urbanizes and runoff peaks and quantity increases, the pre-existing drainage network will become progressively unable to handle the increasing flow rates, resulting in local flooding.
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Channel Flows
Become More Erratic
| Adverse impacts on habitat values and the stream’s reliability for water supply purposes.
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Depth of Groundwater Analysis
* how deep wells must be drilled for water supply - greatly impacts cost
* determining the feasibility of stormwater infiltration/retention measures
* determining the feasibility of siting septic system leaching fields
* Obviously groundwater quality and contamination impacts its usefulness for water supply purposes
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Egress Code
Code for how to exit a place - fire exits etc.
226
Regulatory Taking
A legal theory that a particular government regulation has so adversely affected the value of real property as to amount to a condemnation of the property, for which the owner is entitled to compensation.
227
Land Evaluation and Site Assessment System. LESA
developed by the USDA to protect prime, unique or locally important farmland from development.
228
COLOR CODING FOR LAND USES
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Yellow - residential
Brown - multi-family and high rise residential
Red - retail and commercial
Purple- industrial
Blue- institutional and public
Gray- industrial utilities
Green- recreation
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229
Plat Map
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Lot line locations and dimensions
Lot numbers
Road and street rights of way
Street names
Utility and other easements
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230
Soil structure
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Platy
Granular
Blocky
Columnar
Prismatic
Structureless
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231
Public Land Survey System (PLSS) section of land
a section is an area nominally one square mile, containing 640 acres, with 36 sections making up one survey township on a rectangular grid.
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ALTA Survey
An ALTA survey, otherwise known as the American Land Title Association survey, is a complete survey you can get for your land that is useful during the due diligence process and for meeting lender and insurer requirements.
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Boundaries
Land Improvements
Zoning Classifications
Roads
Property Features
Legal Access to Property
Easements and Encumbrances
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233
Soil Elasticity
Ability of soil to return to its original shape after being subjected to a load condition.
234
Aggradation (or alluviation)
term used in geology for the increase in land elevation, typically in a river system, due to the deposition of sediment.
235
Fasciation
also known as cresting, is a relatively rare condition of abnormal growth in vascular plants in which the apical meristem (growing tip), which normally is concentrated around a single point and produces approximately cylindrical tissue, instead becomes elongated perpendicularly to the direction of growth, thus producing flattened, ribbon-like, crested (or "cristate"), or elaborately contorted tissue.
236
chlorosis
Chlorosis is a yellowing of leaf tissue due to a lack of chlorophyll. Possible causes of chlorosis include poor drainage, damaged roots, compacted roots, high alkalinity, and nutrient deficiencies in the plant. The lack of iron is one of the more common nutrients associated with chlorosis.
237
drainage wind
wind that blows from a higher elevation to a lower elevation
238
Components of 100 year floodplain
Channel
Floodway
Flood Fringe
239
Time of concentration
amount of time needed for water to flow from most remote point in a watershed to the watershed outlet.
240
Bearing Capacity
the capacity of soil to support the loads applied to the ground. The bearing capacity of soil is the maximum average contact pressure between the foundation and the soil which should not produce shear failure in the soil
measure of a soil to decrease in volume under the pressure of a given weight.
241
Community resource inventory
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Wetlands
Archeological sites
Scenic views
Significant wildlife habitats
forests
floodplains
farmland
aquifers
historic structures
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242
Rate of runoff equation
Q=ciA
Q- peak discharge in cubic ft per second
c-runoff coefficient
i-rainfall intensity measured in inches/hour
A-drainage area in acres
243
Program Development aspects
Personal
political
Financial
Social
244
Hydrophobic Soils
exhibit water repellence
decreased infiltration
increased runoff
increased erosion
wildfires cause soils to become hydrophobic
245
Stadia measurement
is a technique of measuring distances with a telescopic instrument
distances are read by noting the interval on a graduated rod intercepted by two parallel cross hairs (stadia hairs, or stadia wires ) mounted in the telescope of a surveying instrument, the rod being placed at one end of the distance to be measured and the surveying instrument at the other.
246
Soil texture classes
largest to smallest
| Sand-silt-clay
247
Max cross slope on ADA walkway without rails
2%
248
Slope inventory and analysis maps
Light value = high elevations
| Dark value = low elevations
249
USGS quadrangle map
topographic map produced by the United States Geological Survey (USGS) covering the United States
A 7.5 minute quadrangle map covers an area of 49 to 70 square miles
including roads, hydrography, contours, boundaries, woodland cover, structures, geographic names, an aerial photo image, Federal land boundaries, and shaded relief.
