Design constraints

Site conditions and design constraints

“What is known” describes the evidence. “Design response” identifies options for the redesign, not existing conditions or approved commitments.

In this section

Footprint and land use
River setback
Western parcel strip and levee
Southern connector / existing western trail
Flood level and grading
Clay and expansive soil
Very slow infiltration
Shallow groundwater
Stormwater treatment
Drainage, litter and sediment
Low-water design requirement
Cooling water is a separate system
Heat and outdoor comfort
Airspace and tall canopy
Utility corridors and roots
Building-edge trees
Regenerative perimeter + security
Fire and servicing
Electrical wildlife conflicts
Existing trees and retention
Tree impacts beyond the 18 removals
Bird-safe glass and lighting
Nesting and grassland management
Noise: name the source edges
Fuel and potentially contaminated soil
Parking and useful shade
Planted roof: engineering envelope
Nesting on buildings and roofs
Habitat next to an airport
Beaver coexistence at this reach
Orchard frontage / public right-of-way
Northern boundary and utility control
Optional public works / land dedication

Footprint and land use

What is known

The July 2025 application defines a ~22.24-acre Project Site and a completed northern lot-line adjustment. It includes buildings, parking, entrances, landscape and utilities. Off-site works are also drawn as part of the project; their inclusion does not transfer land ownership.

Design opening

Rework the campus landscape, parking and arrival as one concept. Use the civil PROPERTY LINE—not LIMIT OF WORK—as the land envelope. Filed plans show design intent, not recorded public-access rights; the current boundary/easement survey determines final usable geometry.

Civil sheet 4.0 · property line, limit of work, easements and sections are distinguished in the legend.

River setback

What is known

Policy 6-34 gives 100-ft general setbacks for buildings, parking and roads, measured from the outer riparian dripline or top of bank, whichever is greater. It treats public trails separately, including continuity along flood-control channels.

Design opening

Use the setback to reserve riparian-compatible campus ground; it is neither the property boundary nor the fence-to-boundary width. Preserve native planting on both sides of the fence where suitable. Any public trail or river-bank intervention needs its own land rights and agency acceptance.

Setback shown in the submitted site plan; use a current surveyed riparian line for layout.

Western parcel strip and levee

What is known

Section C labels 28–180 ft from the western property line to the proposed fence, plus 13–44 ft from fence to internal road. The existing Guadalupe River Trail/levee is farther west; the river lies beyond. These are printed drawing ranges, not net unobstructed planting widths.

Design opening

Use the printed 28–180-ft outer and 13–44-ft inner ranges as the filed sectional envelope, not a buildable-area calculation. Valley Water requests runoff away from the levee toe and trees at least 15 ft from it. Fit planting to utilities, slope and the current surveyed levee/setback line.

Section C · 2024-filed set, sheet dated Dec 2023; not to scale. Dimensions are printed, not measured from the image.

Southern connector / existing western trail

What is known

The existing Guadalupe trail runs along the west. Separately, §3.3.8 proposes an east–west path inside the southern parcel edge. Section B shows 20 ft property-to-fence, a 19-ft recreational easement, and a 10-ft path with 3-ft shoulders. The final levee link is off-property.

Design opening

Keep the proposed southern path outside facility security. Preserve the existing western trail; its final connection from the campus boundary lies on Valley Water land. Extra rest/planting space must be demonstrated beyond path, shoulder and inspection needs; an easement is not evidence of public ownership.

Section B · proposed southern connector, not the existing Guadalupe River Trail. Bioretention sits inside the fence.

Flood level and grading

What is known

Terracon reports FEMA Zone AH with base flood elevation 27 ft NAVD88 and design groundwater elevation +24 ft. The Lower Guadalupe capacity study proposes changes to levees and structures along this river corridor.

Design opening

Grade public routes and planted depressions with the flood model, not just a decorative contour plan. Preserve overflow paths and avoid berms that redirect floodwater to buildings or neighboring land. River-edge levels need to fit the district’s flood works.

Clay and expansive soil

What is known

Terracon describes near-surface clay with sand layers below, including roughly 15–30 ft of clay over 5–20 ft of sand before deeper clay. Its expansion testing warns of moisture-related movement near improvements. This is not a horticultural soil analysis.

Design opening

Favor clay-tolerant plants in broad unpaved ground. Use designed soil volumes under pavement and separate tree-root moisture from foundations. Post-grading soil chemistry, compaction and drainage determine amendment and irrigation choices; a clay label alone cannot specify them.

Very slow infiltration

What is known

Four field tests returned 0.24, 0, 0.01 and 0.02 inches/hour. Terracon recommends a minimum factor of safety of two for design and locating retention/detention at least 10 ft from structural improvements.

Design opening

Use underdrained treatment with a defined outlet where soils cannot absorb runoff. Do not promise meaningful groundwater recharge from these measured rates. Put wetter planting where the engineered water balance sustains it.

Shallow groundwater

What is known

Groundwater depths vary between investigations; the later tank-area work found water about 2–16 ft below ground. Terracon recommends design groundwater elevation +24 ft. A one-day borehole reading is not a dry-season irrigation supply.

Design opening

Explore seasonal depressions and, if the dry-season water balance supports it, a persistent wet refuge. Set levels against groundwater, foundations and overflow routes. Groundwater observed in a borehole is not automatically an available or clean supply.

Stormwater treatment

What is known

The July 2025 description provides approximately 31,000 sq ft of bioretention. The plans show treatment cells, underdrains and storm-drain connections. NOAA specifically raises pollutant-laden parking runoff and increasingly severe storms.

Design opening

Keep treatment area and hydraulic capacity while diversifying vegetation. Separate inlet sediment capture, wettest planted zones, dry shoulders and maintenance access. A functioning planted filter is the primary benefit; wetland habitat requires a suitable water regime.

Central treatment cell and planting layout, sheet 10.5.

Drainage, litter and sediment

What is known

The maintenance details address sediment, vegetation, underdrain clogging and drawdown. A basin full of standing water, sediment or blocked inlets will not perform like the intended planted filter.

Design opening

Keep inlets, cleanouts and overflow structures visible and reachable. Provide stable maintenance access and plant bands that tolerate both wet weather and summer drying. Retain useful leaf litter in habitat areas without obstructing stormwater structures.

Low-water design requirement

What is known

The filed landscape irrigation demand is about 10.2 acre-feet/year, using recycled water. It is not a legal maximum. Water conservation is a core redesign requirement; the applicable City/MWELO calculation determines the permitted budget.

Design opening

Minimize long-term irrigation with climate-fit hydrozones and drought-season character. Quantify establishment and mature demand separately, including roofs and wet features; target less than the filed landscape baseline. Check recycled-water salts, prevent leaks and keep dry oak crowns out of irrigated basins.

Irrigation layout, sheet 10.10; not a water-budget calculation.

Cooling water is a separate system

What is known

Roof-mounted hybrid fluid coolers operate wet or dry. The filed maximum recycled-water demand is about 680 acre-feet/year for cooling. Mineral-concentrated blowdown is routed to the sanitary system.

Design opening

Do not depict cooling blowdown as a clean supply for a pond or habitat wetland. Any reuse concept requires treatment and an engineered water-quality balance. Landscape water savings and cooling-water demand are separate quantities.

Illustrative visible plume at a fluid cooler; equipment reference from the plume memo.

Heat and outdoor comfort

What is known

The submitted cooling system rejects heat at roof level. The plume memo evaluates thermal/visible plumes for aviation; it does not provide a measured pedestrian-temperature map for the finished campus.

Design opening

Shade occupied routes and seating against solar heat, especially beside pavement. Locate resting spaces away from exhaust/service areas. Waste-heat reuse would need a defined engineering system and a nearby user; it is not part of the submitted landscape.

Airspace and tall canopy

What is known

The buildings are about 101 ft high at the roof and 136 ft at the parapet high point in the submitted description. Drawings show an avigation easement; the later footprint rotation responds to FAA airspace review.

Design opening

Keep proposed mature tree heights within the applicable airspace/easement envelope. Locate large native canopy where both root space and overhead clearance exist; low meadow/shrub structure is the opportunity under restrictive corridors.

SJC04 parcel in runway-approach context; airspace study Figure 2.

Utility corridors and roots

What is known

The drawings show water, sewer, electrical, jet-fuel and riparian easements plus overhead transmission lines. The landscape notes call for trees at least 10 ft from utilities; the description also lists service-specific separations.

Design opening

Lay out a composite utility-and-root plan before placing trees. Use low vegetation above service corridors and concentrate canopy in genuine soil corridors. An easement is not spare space for deep excavation, boulders or permanent structures.

Canopy/easement layout, sheet 10.12; the tree-height note refers to PG&E coordination.

Building-edge trees

What is known

Landscape general notes use offsets of 5 ft for small, 12 ft for medium and 20 ft for large trees from buildings. Terracon recommends no trees/large shrubs within 20 ft of improvements unless a root barrier limits roots near structures.

Design opening

Resolve the more protective combined root/foundation arrangement, not simply the smallest listed offset. Use low planting beside buildings and give larger native trees space outside those interfaces. Root barriers do not replace adequate soil volume.

Regenerative perimeter + security

What is known

The filed 8-ft security perimeter encloses both planted landscape and infrastructure. Sheet 10.5 shows trees, beds and bioretention inside it. The fence, property boundary and equipment-protection limits serve different purposes.

Design opening

Connect perimeter planting and internal gardens as a multi-species habitat corridor. Keep inspection access, sightlines and critical routes clear; position planting so it does not provide climbing access to the fence or reach energized equipment. Any passage through the secure boundary needs the security designer’s acceptance.

Sheet 10.5 · internal habitat opportunities are not removed by perimeter security.

Fire and servicing

What is known

The main campus entrance and ring road provide truck/fire access. Northern emergency access crosses a neighboring-property easement. The civil notes propose an emergency-vehicle-access easement for the main entrance and roads around/between buildings.

Design opening

Recompose entrance planting, paving and parking around verified turning/service envelopes. Preserve the emergency easement and hydrant/fuel access; it does not grant general public entry. Alterations beyond the parcel or within shared access rights require the affected owner/authority’s agreement.

Ring road and operational yards in the submitted arrangement.

Electrical wildlife conflicts

What is known

The “fireball squirrels” anecdote describes concern about animals damaging electrical systems across data-center projects. It is not an SJC04 rule. The real design issue is the interface between habitat, conductors, equipment enclosures and maintenance.

Design opening

Keep attractive habitat away from energized equipment; protect equipment against animal entry. Retain ecological function elsewhere instead of relying on blanket rodent poisoning or adding raptor perches near the electrical yard.

California ground squirrel species reference; not evidence of current burrows at SJC04.

Existing trees and retention

What is known

HMH inventories 65 on-/off-site trees, not 65 Microsoft-owned trees. The north/northwest group includes coast live oaks #49–51/#54–63 and cork oaks #52–53. Oak #59 is 51 inches in trunk diameter, rated Good for preservation in 2022.

Design opening

Protect viable existing canopy by adjusting on-parcel yard/road geometry and coordinating boundary-tree work. Put tree IDs, ownership and root protection on the same plan. The mitigation drawing lacks matching IDs and cannot alone establish #59’s proposed removal or retention.

Numbered north/northwest oak group from HMH Exhibit A; locate trunks before changing nearby earthworks.

Tree impacts beyond the 18 removals

What is known

The 2025 description proposes 18 on-site removals, plus 3 Orchard Parkway street trees for access. Another 10 street trees may be removed/replaced for sidewalk work. The replacement schedule says 66; BIO-4.1 says 71.

Design opening

Compare a retention-led alternative with the submitted road, gate, sidewalk and utility geometry. Mature canopy takes decades to replace. Keep street-tree impacts visible, and resolve the permit replacement total before fixing the planting schedule.

Submitted tree mitigation plan · crosses indicate removal; inventory IDs are not printed on these symbols.

Bird-safe glass and lighting

What is known

Filed measure BIO-2.1 limits façade-glazing reflectivity to 20% and untreated glazing to 10% of combined façade area from ground to 60 ft. It also requires shielded lighting directed away from the river and places bird-attracting vegetation/water away from glass.

Design opening

Treat glass at every new habitat interface, including a planted roof or nesting feature above the filed 60-ft treatment zone. Integrate sheltered nesting with collision-safe flight paths, shielded lights and maintenance access. Keep the river dark without creating unsafe public routes.

Nesting and grassland management

What is known

April 2025 pre-mowing surveys found no burrowing owls or suitable burrows in the surveyed campus/accessed buffer, but recorded an active red-winged blackbird nest in mustard. Earlier records and agency comments identify nearby owl use.

Design opening

Retain both short open patches and taller nesting cover rather than mowing every area uniformly. Time vegetation removal around active nests, with the project’s pre-activity survey measures. Planting change should replace useful habitat structure as weeds are removed.

Inactive ground-squirrel burrow photographed during the 2023 study, not the 2025 survey.

Noise: name the source edges

What is known

Generators occupy the north and south sides of both buildings; two more serve the northwest water-tank yard. Coolers are on both roofs. The older model gives the southwest boundary 57.3 dBA operational / 62.7 dBA with generators.

Design opening

Test resting/nesting locations against those north/south building faces, the northwest plant yard and roof discharge. The southwest river edge is not inherently quiet. Use updated noise contours to choose refuges; ordinary vegetation alone is not an acoustic barrier.

Fuel and potentially contaminated soil

What is known

The filed design includes underground diesel storage and tanker delivery, with spill-control procedures. HAZ-1.1 requires a soil-management plan where contaminated soils/groundwater are encountered; nearby cleanup sites do not prove this parcel is contaminated.

Design opening

Keep fuel containment separate from habitat drainage. Do not reuse excavated soil in public planting or edible landscapes without suitable test results. Deep basins and root trenches must fit both the geotechnical and contamination-management design.

Parking and useful shade

What is known

On-site parking is part of the redesign envelope, not public-street land. The 2025 proposal supplies ~145 spaces and says off-street parking is no longer required by the City. Sheet 10.12 projects 73.5% shade over parking alone; 30.8% including drive aisles.

Design opening

Test reduced nonessential parking and changed aisle geometry to create shared native rooting/habitat areas. Retain accessible parking, operational capacity and fire/utility access. Neighboring parking beyond the parcel is not available for this reallocation.

Actual canopy-shade tables, sheet 10.12 / PDF p38. These are projected, not existing, shade.

Planted roof: engineering envelope

What is known

SJC04’s roof carries a dense cooler platform, administrative HVAC and high screening parapets. The filed strategy specifies a reflective cool roof; the documents do not assign spare load capacity to vegetation.

Design opening

Test saturated substrate loads, waterproofing/root barrier, drainage/overflow, wind uplift, fire access and service/crane routes. Keep intake/exhaust paths clear. Compare a partial roof meadow, a lower canopy roof and the baseline cool roof for habitat, water and energy outcomes.

Figure 3.3-6 · submitted arrangement; the unshaded administrative strip still contains equipment and access.

Nesting on buildings and roofs

What is known

Birds differ in nesting needs; a generic box cannot serve every focal species. Cornell NestWatch provides species-specific box features. Burrowing owls use ground burrows and open foraging habitat; a safe roof breeding system is not established here.

Design opening

Test sheltered native cavity-nester modules on non-operational façades/canopies, with suitable temperature, predator protection, drainage and cleaning access. A roof-owl option must solve burrows, satellite refuges, prey access and unfledged-young safety before being treated as habitat.

Habitat next to an airport

What is known

The campus sits beside SJC’s approach environment. FAA guidance addresses water, landscaping and structures that attract hazardous wildlife; it calls for species- and site-specific risk assessment, not a blanket ban on biodiversity.

Design opening

Evaluate new nesting attractions, roofs, ponds and wildlife movement with SJC’s qualified wildlife specialist. Favor compatible habitat functions; avoid concentrating hazardous flocks or routing birds across flight paths. The assessment must shape which species are invited where.

Site and airport approach context from the project airspace study.

Beaver coexistence at this reach

What is known

Valley Water’s Guadalupe assessment identifies both ecological benefits and risks from tree cutting and dam-related flooding. The sources reviewed do not quantify beaver abundance or damage at SJC04. CDFW’s 2025 restoration report is not a census of this river reach.

Design opening

Borrow storage/complexity in on-parcel drainage without attracting animals to unsafe assets. Protect priority trees if actual activity warrants it. River dams, flow devices and levee interventions need a separate manager-led coexistence scheme; no releases, assumed overpopulation or default control.

Orchard frontage / public right-of-way

What is known

Section D shows 20-ft private-utility and 10-ft public-service easements in the landscape beside the right-of-way. Outside that line are an existing ~5-ft sidewalk/~7-ft parkstrip and a proposed 7-ft bike lane/3-ft median. It does not dimension a continuous outside-fence planting strip.

Design opening

Use campus frontage for compatible low-water planting; coordinate trees with easement access. Street, curb, crossing and sidewalk design is a City interface. Section D explicitly describes the bike lane as project-funded and Public Works-built—not privately owned landscape.

Section D · existing sidewalk/parkstrip and proposed public bike-lane improvement; printed dimensions only.

Northern boundary and utility control

What is known

Northern emergency access uses a neighboring-property easement. The northeast contains a Microsoft substation and a PG&E-owned/operated switching station within the Project Site. Neighboring parking and landscape shown on the plans are not campus redesign land.

Design opening

Sections A/G show 10 ft between the existing northern property line and proposed fence at those sections, not a uniform site-wide strip. Section E’s 2–27-ft neighboring landscape is outside the parcel. Retain utility/emergency rights; design only compatible campus planting around these envelopes.

Section E · neighboring landscape/parking is beyond the proposed property line; electrical compound has separate control.

Optional public works / land dedication

What is known

The filed scheme already proposes Microsoft-funded Orchard bike-lane and signal improvements. Valley Water identifies the river-trail link as being on its land. This supports a partnership design option—not an existing right to redesign the trail, levee or river.

Design opening

Separate the campus scheme from a Microsoft-funded public extension. The receiving owner must accept design, construction/access rights and maintenance. A City agreement alone cannot authorize work on Valley Water land; donating improvements does not change ownership. On-parcel public dedication is a separate choice.