Geology, Rocks and Landforms

Considerations of Site Analysis

• Site analysis involves studying a site based on ecological, cultural, and aesthetic factors.

Ecological Factors

• Geology studies the Earth's structure, materials, processes, and history
• It focuses on rocks, minerals, soil composition, and the physical/chemical processes shaping Earth over time.

Kinds of Rocks

• Igneous rocks form from cooled and solidified molten rock (magma or lava).
• Sedimentary rocks are a result of accumulation, compaction, and cementation of sediments.
• Metamorphic rocks form when existing rocks change due to high temperature, pressure, or chemically active fluids.

Geomorphology

• It studies landforms and processes that shape the Earth's surface.
• Geomorphology understands the formation and development of natural landscapes.
• Physiography describes and classifies Earth's surface features (landforms) and their arrangement.
• It involves mapping and categorizing landforms by their characteristics.

Landforms

• Irregularities exist on the earth’s surface
• These are derived from volcanic, glacial or erosional processes.

Types of Landforms

• Valley
• Plains
• Mountains
• Hills
• Plateau
• Volcano

Basic Geomorphologic Information

• Soil Properties related to composition and texture should be studied
• Drainage of the land
• Topography, including slopes
• Degree of soil erosion

Soil Properties

• Composition refers to the materials making up soil such as, mineral particles, organic matter, water and air
• Mineral particles comprise 50-80% of soil volume, forming the skeletal structure
• Sand and gravel particles provide high stability and bearing capacity.

Composition continued

• Organic Matter: varies drastically in soils, limiting building structure suitability; important for soil fertility, moisture retention, and landscaping.
• Water content varies with particle sizes, drainage, topography, and climate; it occupies spaces between particles, with organic soils absorbing measurable amounts.
• Air occupies the remaining space not taken up by water; absence of air indicated in groundwater layers formed by gravity water in the subsoil.

Soil Texture

• The term used to describe the composite sizes of particles in a soil sample.
• Loam is an ideal soil texture, having 40% silt, 40% sand and 20% clay.
• Soil Texture aids moisture retention and proper drainage and is easy to cultivate.

Drainage

• Good Drainage: Soil's ability to transfer gravity water downward through infiltration, permeability and percolation

Good Drainage elements

• Infiltration is the rate at which water penetrates the soil surface, measured in cm or inches per hour.
• Permeability is the rate at which water moves within the soil, measured in cm or inches per hour.
• Percolation is the rate at which water is taken up by the soil in a pit or pipe, typically measured in inches per hour and predominantly used in wastewater absorption tests.

Poor Drainage

• Gravity water is not readily transmitted in the soil
• Soil remains frequently or permanently saturated, leading to water standing on the surface
• This is caused by local water accumulation, high groundwater levels, and small particle sizes obstructing infiltration of water

Topography and Slopes

• Slope Analysis requires understanding local geologic, soil, hydrologic, and vegetative conditions.
• Slope Form is expressed graphically as a slope profile of a slope drawn to known proportions with distance on the horizontal axis and elevation on the vertical axis.

Slope Gradients

• Angle of Repose: the maximum angle at which a soil can incline safely without failure.
• Slope Gradient: the land surface's inclination relative to the horizontal plane
• Slope Gradient is referred to as "slope percent" or "slope" and is determined at a point along a line oriented up and down slope.

Methods of Expressing Slope

• Percentage of Slope
• Ratio of Slope
• Angle of Slope

Slope Patterns

• Slope patterns for elementary and high school campuses range from generally flat to harsh, steep slopes, affecting buildability from highly buildable to unbuildable based on the degree of slope.
• Topography of proposed sites for National Housing Authority(NHA) housing should not exceed 15% maximum gradient for buildable slopes
• for above 300-600 units per hectare slope should be below 5%, and for projects with density of 300 units or below per hectare, slope should be 5% to 15%.

Topographic Map

• Represents earth's surface shape with slope patterns for visual expression.
• Contours are imaginary lines connecting points of equal elevation above or below a reference surface (mean sea level).
• A Slope Map prepares and visually expresses slope patterns on the topographic map.

Soil Erosion

• Soil erosion transpires when rocks break down (weathered) into small fragments that are carried by wind, water, ice and gravity.
• Energy for soil erosion is solar and gravitational.
• Factors to consider in forecasting erosion rates include vegetation, soil type, rainfall frequency and intensity, and slope size and inclination.

Soil Erosion Prevention

• Grading modifies landform for new structures, parking, circulation, and drainage.

Grading Techniques

• Balanced Grading
• Cut and Fill
• Sloped Grading
• Stepped Grading

Importance of Site Grading

• Proper Drainage protects structures from water accumulation.
• Foundation Stability ensures a solid base, reducing settlement or shifting risks.
• Erosion Control directs water runoff to protect vulnerable areas.
• Accessibility and Safety ensures level, smooth, and accessible paths and entrances.
• Aesthetic Appeal enhances landscaping for pleasing contours and integration with architecture.

Hydrology

• This is the natural science that studies the waters of the Earth and their properties, distribution, circulation, and their reaction to the living environment
• Hydrologic Cycle is the the movement of water from the oceans to the atmosphere to the continents and back to the sea

Water Table

• Is the upper boundary of the zone of groundwater, which is the top of unconfined aquifer

Aquifer

• It's a permeable geological stratum which stores and transmits groundwater in significant quantities.

Watershed

• A geographic area of land bounded by topographic features that captures precipitation, filters, stores and draains water to a shared destination.

Importance of Hydrology in Site Analysis

• Flood Risk Management which aids in flood control and prevents property damage
• Stormwater Management which aids in the design of the drainage system and maintaining Water Quality
• Infrastructure Design is responsible for the structural integrity and traffic flow and safety

Vegetation

• Vegetation serves as a good indicator of soil and microclimate.

Forms of Plants

• Trees are woody perennial plants with a single stem/trunk, growing tall with lateral branches.
• Shrubs are woody plants smaller than trees, with multiple stems arising near the ground surface.
• Groundcover includes low-growing, spreading plants that help prevent weeds from growing
• Vines are climbing/trailing woody-stemmed plants related to grapevines.

Plant Classification Based on Habitat

• Terrestrial plants live or survive on land (e.g. mango, rose).
• Aerial plants live on trees or hang in the air (e.g. orchids).
• Aquatic plants live in water (e.g. lotus).

Uses of Plants

• Engineering Use includes control of solar radiation and glare, wind control, air cleaning, noise absorption, and erosion minimization
• Architectural & Aesthetic Use encompasses space definition, provision of enclosure and privacy, view control, mood setting, and landscape color/texture.

Wildlife

• Refers to various species of animals, plants, and other organisms inhabiting an area of an ecosystem.
• Site analysis considers wildlife by assessing the natural environment, identifying species, and determining potential development impacts.

Habitat Elements

• Openland Wildlife includes birds and mammals commonly associated with crop fields, meadows, pastures, and non-forested lands such as grain and seed crops, grasses and legumes as well as Wild herbaceous and Hardwood woody plants

Woodland Wildlife

• Woodland Wildlife requires various combinations of grasses, legumes, wild herbaceous upland plants, hardwood woody plants and cone-bearing shrubs such as pines

Wetland Wildlife

• Wetland Wildlife includes birds/mammals needing habitats such as Wetland food plants or wild herbaceous plants of moist/wet sites, not submerged or floating aquatic species, shallow water not deeper than 5 ft., excavated ponds with ample water supply of one acre and average 6ft depth.

Key Aspects of Wildlife in Site Analysis

• Biodiversity Assessment: Identify species present.
• Habitats and Ecosystem Mapping: Analyze habitat types and map locations of endangered or protected species.
• Impact of Development: Evaluate effects on wildlife and habitats (destruction, fragmentation).
• Ecological Connectivity: Identify wildlife corridors
• Sustainable and Conservation Measures: Implement conservation efforts (preserve habitats, create buffer zones/green spaces).
• Legal and Regulatory Considerations: Ensure compliance with environmental laws protecting endangered species.

Importance of Wildlife Habitats in Site Planning

• Conservation of Biodiversity: ensures development plans do not negatively impact endangered species or vital ecosystems.
• Ecosystem Services: Considers the wildlife's role in ecosystem services which supports pollination, water purification, soil regeneration, and carbon sequestration.
• Sustainable Development: incorporates wildlife site analysis to promotes sustainable development practices to minimize harm to the environment while promoting responsible land use.

Importance of Wildlife Habitats in Site Planning continued

• Public Awareness and Value: Areas rich in wildlife offer recreational and educational value, contributing to ecotourism, outdoor activities, and environmental education to the value and appeal of the area.
• Risk Mitigation: Aims to avoid conflicts with conservation laws and helps to mitigate the risks of environmental degradation to reduce project delays or legal challenges.