Siting a 120-Bed Hospital on a 12% Slope

Start from the constraint that cannot be bought: the 10% road grade. The site falls 12% toward the sea, so a road running straight down the fall line is already illegal before you add the transition at the provincial road. The access must therefore climb across the slope - approach from the northeast boundary and run roughly along the contour, then turn. Show the profile; a road that looks fine in plan can still be 14% at the driveway apron.

Platform. The budget buys one retaining wall, so use it where it does the most work: cut into the uphill side and let the building sit on a bench, with the cut face retained uphill and the fill side carried on short columns or a graded slope. Cutting on one face and filling on the other balances earthworks, keeps the import/export bill down, and - critically - keeps the building out of the natural drainage line. Never place the platform across the low point of the site.

Siting rules to state explicitly:

• Building parallel to the contours, long axis roughly north–south, so patient rooms get morning and late-afternoon light without west glare on the operating side.
• Emergency department and ambulance drop-off at the road-level (upper) end, so an ambulance never climbs a wet ramp at speed.
• Do not cut the ridge line at the top of the site; that is what triggers slope failure and the neighbours' complaints.

Deliverable: a grading plan with existing and proposed contours, spot levels at the platform corners, and the cut/fill volumes stated. If the volumes do not roughly balance, the design is not finished.

Wind and fall line govern everything on a hospital site. Prevailing wind is from the southwest, so the seaward side is the dirty side and the northeast - toward the road and the neighbours - is the clean side. The fall line runs from northeast down to the sea, so anything that spills will travel west.

• STP: downwind and downhill from the building, on the seaward side, with the prevailing wind carrying odour away from wards and from the road boundary. Keep it out of the natural drainage swale and provide a buffer. It must be accessible to a vacuum truck without crossing the ambulance route.
• Generators: downwind, and never below the fresh-air intakes of the wards (exhaust rises and drifts). Locate on a level pad with the fuel day-tank bunded; noise matters more at night than in the day - check the setback to the nearest ward window with the actual dBA at the property line.
• Air intakes: on the windward (northeast) face, high level, clear of the loading dock and the generator plume. This is the single most common hospital siting error: the intake ends up on the same face as the exhaust because the mechanical room was placed first.
• LPG bulk tank: downwind, away from the emergency department and the ambulance route, with a fire-rated separation to the building, vehicle impact protection, and a clear approach for the fire truck. Confirm distances against R.A. 9514 and the supplier's installation standard - do not size the compound from habit.
• Ambulance route: covered canopy at the ED door, a turning circle the driver can make without reversing, and separation from the public parking.

Test the arrangement: sketch the wind rose and the fall line on the site plan and confirm that nothing that smells, smokes or burns sits upwind or uphill of a patient window.

The view is legitimate; the risk it creates is not. Putting the main glazed lobby on the downhill west face means the building sits in the path of every drop of water that lands uphill of it.

Required measures:

• Intercept the uphill water before it reaches the building. A lined interceptor drain with a gradient to a controlled discharge, set at least 1.5–2.0 m off the uphill wall, plus a graded swale. A drain hard against the wall silts, blocks and then leaks into the footing.
• Do not dam the natural drainage path. Water must leave the site where it entered, at the same or lower level - the Civil Code rules on natural drainage and the Water Code easements both point the same way, and the downstream neighbour will complain the first rainy season. Provide a defined outfall and show it on the plan.
• Keep the footing out of the wet zone. With 12% slope and cut on the uphill side, the footing on the fill side will be founded on disturbed ground unless the geotechnical engineer says otherwise. Get the recommendation in writing before the structural design is frozen.
• Protect the downhill glazing. Overhangs, a raised plinth and a positive step at the door to stop sheet flow entering the lobby, plus impact-resistant glazing if the site is exposed.

Then argue the design point: the sea view is best framed by a raised terrace and canopy that also do the weather protection. The client gets the view, the water gets a path around the building, and the geotechnical and civil engineers have signed off before the architecture is fixed.