LA Landscape cheat sheet

Contract types: lump sum (fixed price for defined scope), unit price (paid per measured quantity, used when quantities are uncertain), cost-plus-fee (owner bears cost risk; used for undefined or fast-track work), and time-and-materials.

Standard AIA-style roles: owner, architect/landscape architect, contractor, and construction manager. In design-bid-build the LA administers the contract but does not supervise means and methods, which belong to the contractor.

Bid package essentials: drawings, specifications, bid form, instructions to bidders, general and supplementary conditions, addenda, and alternates. Addenda issued during bidding become part of the contract.

Pay applications are certified by the contractor, reviewed by the LA for percentage of work in place, and typically retain 5-10% retainage until substantial completion.

Substantial completion triggers warranty start, owner occupancy, and release of some retainage; final completion follows punch-list closeout and release of final payment.

Change order vs. construction change directive: a change order is signed by all parties; a CCD directs work before price agreement is reached and is later converted to a change order.

Critical-path schedule logic: float is the slack in a non-critical activity; delaying an activity beyond its total float delays the project and may support a time extension claim.

Submittal review stamps: approved, approved as noted, revise and resubmit, rejected, and submit specified item. The LA's review does not relieve the contractor of responsibility for compliance.

Site inventory covers physical (topography, soils, hydrology, vegetation, climate), biological, cultural (land use, circulation, views), and legal/regulatory data; analysis interprets constraints and opportunities from that data.

Slope classes: 0-3% generally buildable and accessible; 3-8% buildable with grading; 8-15% requires terracing and careful erosion control; over 15-25% is severely limited and often protected.

USDA soil textural triangle: sand, loamy sand, sandy loam, loam, silt loam, clay loam, silty clay, and clay. Loam (roughly 40% sand, 40% silt, 20% clay) is the agronomic ideal.

Site carrying capacity and suitability analysis use overlay mapping (McHarg method) to combine factor layers such as slope, soils, floodplain, and vegetation into a composite suitability map.

Sun and shadow study: solar altitude and azimuth vary with latitude and season; winter sun angles are low and shadows long; summer angles are high and shadows short.

Drainage patterns: dendritic (branching, uniform soils), radial (conical peaks), trellised (folded strata), and deranged (glaciated, poorly integrated).

Viewshed analysis maps the area visible from a point or route; it combines elevation data with observer height and screening vegetation or structures.

Data sources: USGS topographic quadrangles, NRCS soil surveys and Web Soil Survey, FEMA flood insurance rate maps, LiDAR-derived DEMs, and aerial/satellite imagery.

Drawing set order: cover and index, general notes and legends, demolition, site layout and grading, utility and drainage plans, planting plans, irrigation, details, and schedules.

Scale conventions: site plans 1"=20' to 1"=50'; grading and utility plans 1"=10' to 1"=20'; details 1"=1' or larger; planting plans commonly 1"=10' to 1"=20'.

Plan symbols: spot elevations as decimal feet (e.g., 102.50), contour intervals typically 1' or 2' for site work, flow arrows, and benchmark references tied to a known datum.

Specification format follows CSI MasterFormat divisions; site work falls in Division 31 (earthwork), 32 (exterior improvements), and 33 (utilities), with landscape planting in Division 32.

Plant schedule fields: symbol, botanical name (genus, species, cultivar), common name, size (caliper or height/spread), root condition (B&B, container, bare root), quantity, and remarks.

Construction documents must be coordinated across disciplines; conflicts between architectural, civil, and landscape sheets are resolved before bid, with the most stringent requirement governing.

Shop drawings and samples are contractor-prepared documents showing fabrication details; they are reviewed for design intent, not for dimensional or field verification.

Record drawings (as-builts) document actual installed conditions and are prepared from contractor markups for the owner's facility records.

Slope formula: S (%) = (rise/run) x 100. A 2% slope drops 2 feet per 100 feet; 1% = 1/8 inch per foot; 2% = 1/4 inch per foot.

Minimum grades: 1-2% for paved walks and plazas for positive drainage; 0.5% minimum for swales and pipes; 4.76% is the maximum ADA ramp slope, with 8.33% maximum cross slope on accessible routes being 2%.

Rational method: Q = CiA, where Q is peak flow (cfs), C is runoff coefficient, i is rainfall intensity (in/hr), and A is area (acres).

Runoff coefficients: lawn 0.15-0.35, gravel 0.35, asphalt 0.85-0.95, concrete 0.90, roofs 0.90-0.95, undeveloped woodland 0.05-0.25.

Manning's equation for open channels and pipes: Q = (1.486/n) A R^(2/3) S^(1/2), where n is roughness, R is hydraulic radius, and S is slope.

Stormwater volume control: detention holds runoff temporarily and releases it slowly; retention holds water permanently (ponds, basins); infiltration practices include bioretention, permeable pavement, and dry wells.

Grading rules: slope away from buildings at minimum 2% for the first 10 feet; never drain toward foundations; use swales and berms to direct flow to inlets or infiltration areas.

Cut and fill balance minimizes haul: average end area method computes volume as V = (A1 + A2)/2 x L for each segment; shrinkage and swell factors adjust for soil compaction.

Soil profile horizons: O (organic), A (topsoil), E (eluviated), B (accumulation), C (parent material), R (bedrock). Topsoil depth of 6 inches is a common minimum for planting beds.

Soil pH ranges: most landscape plants tolerate 6.0-7.0; acid-lovers (rhododendron, blueberry, azalea) need 4.5-5.5; alkaline-tolerant species include juniper and lavender.

CEC (cation exchange capacity) measures a soil's ability to hold nutrients; high clay and organic matter raise CEC; sandy soils leach nutrients readily.

Irrigation: evapotranspiration (ET) drives scheduling; drip irrigation is 90%+ efficient, sprinklers 60-80%, and overhead flooding less. Apply water to the root zone depth, not the surface.

Macronutrients N-P-K (nitrogen, phosphorus, potassium); nitrogen drives vegetative growth, phosphorus supports roots and flowers, potassium supports stress tolerance and fruiting.

Planting specifications: root ball diameter is roughly 10-12 inches per inch of trunk caliper; planting hole should be 2-3 times the root ball width and no deeper than the root ball.

Native and adapted plant selection reduces irrigation and maintenance; invasive species (e.g., kudzu, English ivy, Japanese knotweed) displace natives and are regulated in many jurisdictions.

Tree protection: critical root zone (CRZ) is often defined as 1 foot of radius per inch of trunk diameter; fencing is required before demolition and grading begins.

Concrete: 4-inch minimum for pedestrian walks, 6 inches for vehicular drives, with 4,000 psi typical; control joints at 1-1.5 times slab thickness in feet (e.g., 10-15 feet for a 4-inch slab).

Pavers: flexible (sand-set) vs. rigid (mortar-set) systems; base depth of 4-6 inches compacted aggregate for pedestrian, 8-12 inches for vehicular; edge restraint is required.

Wood decay resistance: naturally durable species (cedar, black locust, ipe) vs. pressure-treated (ACQ, copper azole); fasteners must be stainless or hot-dip galvanized to avoid corrosion.

Retaining walls: gravity walls rely on mass; cantilever walls use a footing and stem; segmental block walls need geogrid reinforcement above certain heights (often 4 feet).

Drainage details: weep holes and drainage gravel behind retaining walls, footing drains with filter fabric, and subgrade drains under paving to prevent frost heave and saturation.

Pond and water feature details: liner (EPDM, PVC, or bentonite), underlayment, edge treatment (coping, boulder, or shelf), and aeration or circulation to prevent stagnation.

Fencing and site furnishings: post embedment depth typically 1/3 of post height plus 6 inches; concrete footings sized to frost depth in cold climates.

Erosion control: silt fence, straw wattles, inlet protection, and temporary seeding; BMPs must be installed before grading and maintained until stabilization.

Zoning regulates use, density, floor area ratio (FAR), lot coverage, setbacks, height, and parking; FAR = gross floor area / lot area.

Parking demand: typical ratios are 1 space per 250-350 sf of office, 1 per 100-200 sf of retail, and 1 per dwelling unit; shared parking can reduce total demand.

Accessible routes must connect site arrival points to building entrances; maximum running slope 1:20 (5%), maximum cross slope 1:48 (2%), and clear width 36 inches minimum.

Accessible parking: 96-inch-wide spaces with 60-inch access aisles; van-accessible spaces are 132 inches wide (or 96 inches plus an access aisle) and must be signed.

Transit-oriented and mixed-use planning reduce vehicle trips; walkability measures include intersection density, block length, and sidewalk continuity.

Floodplain management: the 100-year floodplain (1% annual chance) is regulated; the base flood elevation (BFE) and freeboard requirements control lowest floor elevation.

Watershed and buffer requirements: riparian buffers of 25-100 feet are common; impervious cover limits (e.g., 10-30%) are used to protect stream health.

Site circulation: pedestrian and vehicular routes should cross as few times as possible; sight triangles at driveways keep views clear of obstructions.

ADA Standards: accessible route slope maximum 1:20 running and 1:48 cross; ramps over 1:20 require handrails, landings, and edge protection.

OSHA construction standards: excavation slopes and shoring required for trenches 5 feet or deeper; competent person inspections daily and after rain.

Professional licensure: LAs are licensed by state boards; practice across state lines requires licensure in that state or a reciprocal agreement; stamping unqualified work is a violation.

Standard of care: the LA owes the client the skill and care ordinarily provided by professionals under similar circumstances, not a guarantee of perfection.

Contracts: scope, fee, schedule, and limitation of liability clauses; indemnification and insurance (general liability, professional liability) are standard provisions.

Environmental review: NEPA applies to federal actions; state-level equivalents (e.g., CEQA in California) apply to state and local projects; Section 106 of the National Historic Preservation Act protects historic properties.

Wetlands and waters: Section 404 of the Clean Water Act regulates discharge of dredged or fill material into waters of the US; a Section 404 permit may be required.

Permits and approvals: grading, building, stormwater (NPDES), floodplain, and tree removal permits; approval timelines should be built into the schedule.

Meeting minutes should record date, attendees, decisions, action items with responsible parties, and deadlines; distribute within a defined period (often 48-72 hours).

RFI (request for information) process: contractor submits a question, LA responds in writing, and the response becomes part of the contract documents if it changes the design.

Transmittals document the exchange of documents, including date sent, recipient, purpose, and action required; they create a chain of custody.

Daily reports record weather, labor, equipment, visitors, and work performed; they are essential evidence for delay and change claims.

Punch lists identify incomplete or defective work; the contractor completes items, the LA verifies, and final payment follows.

Photo documentation should be dated, located, and captioned; it supports as-built records and dispute resolution.

Written notice requirements: most contracts require notice of changed conditions or claims within a specified period (e.g., 14-21 days) or the claim may be waived.

Public participation: charrettes, open houses, and comment periods gather input; documentation should record how comments were addressed.

Wetlands are identified by hydric soils, hydrophytic vegetation, and wetland hydrology; delineation follows the US Army Corps of Engineers manual and jurisdictional determination.

Endangered species: the federal Endangered Species Act prohibits take; Section 7 consultation applies to federal actions; state lists may add protection.

Historic preservation: Section 106 of the NHPA requires review of federal undertakings for effects on historic properties; the National Register of Historic Places lists significant sites.

Cultural landscapes include designed landscapes, vernacular landscapes, and ethnographic landscapes; treatment options are preservation, rehabilitation, restoration, and reconstruction.

Stormwater and water quality: low-impact development (LID) and green infrastructure (bioretention, green roofs, permeable pavement) manage runoff at the source.

Brownfield remediation: Phase I environmental site assessment reviews records; Phase II involves sampling; cleanup standards vary by jurisdiction and intended use.

Tree and habitat protection: ordinances may protect heritage trees, require tree surveys, and mandate replacement planting ratios.

Climate and microclimate: vegetation shading reduces heat island effect; windbreaks reduce heating loads; urban tree canopy targets of 30-40% are common.