12.3 Landscape Architecture & Site Development Elements
Key Takeaways
- The Philippine Green Building Code requires at least 50% of the required Unpaved Surface Area (USA) under Rule VII/VIII of the National Building Code to be vegetated with indigenous or adaptable species.
- Philippine park and open-space design guidance commonly targets retaining or absorbing roughly 80% of on-site rainfall through combined green infrastructure and permeable surfaces.
- Bioswales are shallow, vegetated channels that convey and filter stormwater while slowing its flow, distinct from retention ponds and detention basins.
- Finished grade should slope away from building foundations to prevent water from pooling and infiltrating, while accessible routes must still meet BP 344 slope and width requirements.
- Hardscape (paving, plazas, walkways) and softscape (planting) must be balanced together, since shade trees are a functional climate response in the Philippines, not decoration.
Landscape Architecture & Site Development Elements
Quick Answer: The ALE tests an architect's ability to integrate and coordinate landscape and site development elements, not to design them at full landscape-architecture depth. Expect questions on hardscape/softscape balance, tree placement for shade and microclimate, stormwater retention and permeable surfaces under Philippine green building guidance, site furniture and lighting coordination, and basic grading and drainage principles for a site plan.
Hardscape vs. Softscape
Hardscape refers to the non-living, constructed surfaces and elements of a site plan: paving, plazas, walkways, retaining walls, curbs, and site structures such as pergolas or trellises. Softscape refers to the living, planted elements: lawns, groundcover, shrubs, and trees. A well-coordinated site plan balances the two rather than treating landscape as decorative leftover space - hardscape defines and hardens circulation and gathering areas, while softscape provides shade, softens hard edges, improves microclimate, and helps manage stormwater. On the ALE, a design showing an unbroken hardscape plaza with no shade trees in a tropical climate is a design flaw, not a stylistic choice: Philippine outdoor comfort depends heavily on tree canopy and shade structures given year-round high heat and humidity.
Planting Design Basics and Tree Placement
Basic planting design at the architect's level of responsibility - not full landscape-architecture depth - covers:
- Canopy trees placed to shade west- and south-facing hardscape and building walls during the hottest parts of the day, reducing solar heat gain on both people and the building envelope
- Understory shrubs and groundcover used to define edges, screen service areas, and stabilize slopes against erosion
- Species selection favoring indigenous and climate-adaptable species that need minimal irrigation and suit Philippine soil and rainfall patterns
- Tree placement set back appropriately from foundations, utility lines, and pavement to avoid root damage, while still close enough to cast usable shade on walkways and gathering spaces
Under the Philippine Green Building Code (2015), a national referral code applied alongside the National Building Code, landscaped or green areas are treated as functional infrastructure rather than ornament: a minimum of 50% of the Unpaved Surface Area (USA) required under Rule VII and Rule VIII of the National Building Code must be vegetated with indigenous and adaptable species. This vegetated surface both cools the site's microclimate and allows rainwater to recharge groundwater instead of running off as stormwater.
Stormwater Management: Retention, Detention, and Permeable Surfaces
Stormwater management on a site plan aims to slow, absorb, or temporarily store rainfall so runoff leaving the site does not overwhelm downstream drainage or flooding-prone areas - a significant concern given the Philippines' monsoon and typhoon climate. Key concepts tested at the ALE's integration level include:
| Concept | Function | Example Site Element |
|---|---|---|
| Retention | Holds captured stormwater on-site, often for reuse or slow infiltration | Retention pond, rain garden |
| Detention | Temporarily holds runoff and releases it slowly to reduce peak flow downstream | Detention basin, underground storage |
| Permeable surfaces | Let rainwater infiltrate through the paving itself rather than sheet-flowing to a drain | Permeable pavers, porous concrete, grass pavers |
| Bioswales | Vegetated, shallow channels that convey and filter runoff while slowing its flow | Landscaped drainage swale along a parking edge |
Philippine park and open-space design guidance calls for a combined approach - green infrastructure such as bioswales together with absorptive surfaces like permeable paving and water-retaining landscaping - commonly citing a target of retaining or absorbing approximately 80% of on-site rainfall for park and recreational grounds, rather than routing all runoff directly to street drainage. An architect coordinating a site plan should treat stormwater controls as integrated with the softscape and grading design, not as a separate engineering add-on solved after the fact.
Site Furniture and Lighting
Site furniture - benches, bollards, trash receptacles, bike racks, planters, signage - and site lighting - pole lights, bollard lights, facade wash lighting, and pedestrian-scale fixtures - must be coordinated with the hardscape and planting layout so they reinforce rather than clutter the circulation pattern. Lighting placement should prioritize pedestrian paths, entrances, and vehicular drop-off/parking areas for safety, while avoiding light spill that disturbs neighboring properties or wastes energy on unused areas. Site furniture should sit at natural pause points - near entrances, along shaded walkways, at forecourts - rather than being scattered without relationship to how people actually move through the site.
Basic Grading and Drainage Concepts
Grading is the manipulation of a site's finished ground elevations to control how surface water moves, ensure accessible slopes at entrances and walkways, and provide positive drainage away from building foundations. The architect's core responsibility at the ALE level is to understand - not necessarily calculate in full civil-engineering detail - that:
- Finished grade must slope away from building foundations, commonly guided by roughly a 2% minimum slope for at least the first few meters, to prevent water pooling against the wall and infiltrating the foundation
- Site drainage should be directed toward designated catch basins, swales, or retention/detention features rather than allowed to sheet-flow uncontrolled across pedestrian paths or neighboring lots
- Accessible routes and ramps must meet BP 344 accessibility slope and width requirements even where surrounding grade is uneven, which often requires the architect to coordinate grading changes specifically to accommodate an accessible path
- Parking areas, being large paved surfaces, must be paved, lit, and provided with adequate drainage per the National Building Code so they do not become a stormwater ponding problem in heavy rain
Grading, drainage, planting, and stormwater controls are ultimately one coordinated system on a resolved site plan: the architect's job in the ALE's Architectural Design and Site Planning subject is to demonstrate that these elements work together, not that each was solved independently.
Which term describes a shallow, vegetated channel used to convey and filter stormwater runoff while slowing its flow across a site?
Under the Philippine Green Building Code, what minimum percentage of the required Unpaved Surface Area (USA) must be vegetated with indigenous or adaptable species?
Why should canopy trees be placed to shade west- and south-facing hardscape and building walls in a Philippine site plan?
In basic site grading, what is the primary purpose of sloping finished grade away from a building's foundation?