So you’ve decided to develop a piece of land – congratulations! Whether you want to build a house, an apartment complex, retail stores or industrial warehouses, the first step is getting the lay of the land. That’s where site surveys come in handy.
Site surveys, sometimes called topographic or land detail surveys, are professional maps of your property showing the location, dimensions, heights and contours of all the natural and constructed features. We’re talking about everything from boundary lines, buildings and roads to vegetation, drainage and utilities across the site.
You’re probably wondering – why do I need one of those complicated-looking survey maps with squiggly contour lines anyway? Can’t I just eyeball my property and figure things out? Well you could, but if you’re investing significant money in a development project on that land, it pays to reduce uncertainty. Relying on guesses instead of accurate data when planning your build could turn out to be an expensive mistake!
A quality site survey provides vital information you can depend on to analyse the property, design appropriately scaled structures in suitable places, and prepare proposals that comply with regulations. So whether you want to subdivide and build townhouses, put up a factory or add a pool cabana in your backyard, start by getting the definitive layout of the site. That’s the foundation that all your other plans will be built on!
I’ll run through the key elements every good site survey report should include to properly represent your land. We’ll also touch on factors like accuracy benchmarks, equipment used and computation methods. My aim is to give you confidence when reviewing the professional survey you commission, so there are no nasty surprises down the track. Let’s get into the details!
Boundaries and Markers
Now let’s talk boundaries and markers – the nitty gritty of defining land ownership. If you’ve ever watched a TV show where neighbours feud over whose fence or garage crosses into whose property, you’ll know boundary disputes can get messy! Avoid potential conflicts by getting clear parcel delineations upfront.
Your site survey should clearly depict all boundaries marking the perimeter of your lot, specifying dimensions in metres or feet. While general boundaries may be fine for reference, formal developments require defined boundaries that are legally binding – more on that later.
Looking at your site map, you’ll see markers represented by symbols like crosses, dots or squares plotted along the boundary lines. These represent actual survey markers or pegs physically embedded in the ground on site.
So what are they for? Well, survey markers form highly accurate points of reference that all other measurements are taken from. They allow the boundary lines and positions of other features to be accurately determined during surveys and precisely reinstated afterwards.
Permanent markers like concrete blocks in the ground are placed at corners, changes of direction or critical points. Site pegs hammered into the soil also serve as temporary position references but can shift over time. Your developer needs to know the exact locations of remaining permanent markers as they ensure constructions like fences or walls align with legal boundaries.
While we’re on boundaries, let’s talk title re-establishment surveys. If you plan construction works, confirming your boundaries are properly defined upfront avoids encroaching on your neighbour’s property! Licensed surveyors can mark boundaries with high accuracy (mostly within +/-20mm tolerance), provide official title re-establishment reports and even lodge updated plans with councils.
Well, that covers off the basics on boundaries and markers. Now let’s move on to visualising the ups and downs across your site…
Topography and Levels
Speaking of the lay of the land, a core part of site surveys is mapping changes in elevation or topography across your property. This allows appropriate grading, drainage and positioning of structures. Let’s explore what your survey report should show in terms of spot levels and contours.
On your site plan, you’ll see a series of thin contour lines that resemble the rings on a tree trunk. These join points that are at the same height value above a reference zero point. The spacing between contours reveals how sharply or gradually the land slopes. Sparse, widely spaced contours indicate a gentle gradient while contours bunched tightly together show steeper inclines.
To make it easier to visualise, index contour lines are made thicker and labelled with their elevation value like 100m or 49ft. Intermediate contours between index lines are shown as thinner unlabeled lines, say every 1 metre rise over a 10 metre horizontal distance for a 1 in 10 gradient. By reading values off various contours, you can gauge the relative change in height between different areas.
As well as contours, spot levels will be shown at critical datum points like boundary corners, pits, drains or retaining walls. These indicate an absolute elevation value for that precise placed as opposed to contours which are relative height estimations. Your surveyor takes levels by using a levelling instrument from a known benchmark to fix vertical elevations across the site with accuracy down to 25mm tolerance.
Why go to such trouble to map heights? Well with contour and spot level data, you can carefully position platforms, ramps or steps to suit the gradient while achieving drainage. You can also calculate cut-and-fill earthworks volumes for excavating building foundations. And your architect can generate 3D site models integrating the terrain. So it pays to have professional topo and level mapping upfront!
On that note, let’s explore documenting existing built structures on site…
Existing Structures
Speaking of structures, your survey must also map key details of any existing buildings, facilities or hardscaping found on the property. This provides your architect, designer and engineer vital spatial data to integrate or demolish existing elements.
The survey drawing will outline the position and footprint of permanent structures like houses, sheds, carports or pools, showing exterior dimensions. Details like the location of external doors, windows, meter boxes and vents should be included. Having services entry points marked allows for connections to new works.
For larger buildings, exterior elevations will indicate eave lines, roof pitches and ridge heights. Photographic surveys can supplement plan data with images of exterior facades. Floor levels may be noted if available, but often internal surveys are also needed.
Your surveyor can help identify load-bearing walls which is crucial intelligence for intended demolition or alterations. Sections of construction like materials used, footing types and framing can also be documented.
Outbuildings and fencing should have dimensions, materials and heights specified on plan. Note distance of setbacks from structures to boundaries which must comply with building codes based on zoning. Elements encroaching into easements may need removal.
If adjoining properties contain significant buildings or trees near the common boundary, your survey drawing should outline these with reduced detail. Photographic recording also helps document overshadowing or overlooking issues from neighbours that may affect planning approvals.
There’s lots involved in surveying existing elements! But comprehensively capturing hard structures provides critical spatial data to incorporate or demolish intelligently when developing your site.
So with the built form covered off, let’s explore mapping infrastructure and services on the property…
Infrastructure and Services
No property stands alone when it comes to utilities and infrastructure. Your site survey mapping must identify all services and easements crossing or bordering the land, whether overhead or underground. This allows proper connection into existing networks when developing.
Surveyors will locate and document the size, level and materials of drainage and sewerage infrastructure like pits, grates, manholes and pipelines traversing your site. Details like invert levels, flow directions and gradients will be captured to facilitate drainage integration.
The position, size and type of water pipes and meters, gas mains & valves, as well as electrical, data and telephone cables serving the lot should also be noted. Overhead power lines, conduit routes and pole structures will be highlighted along with clearance dimensions that impact building envelopes beneath.
Easements for authorities to access, maintain or expand adjacent infrastructure should be delineated and dimensioned on your site plan. Construction over council easements is often restricted so knowing the locations early is vital. Encroaching fences or minor structures may need relocating if found occupying easement zones without approval.
Details of stormwater connections, sewer junction points and water metre locations allows your designer to appropriately interface proposed works with existing networks. Having surveys capture all utilities and easements on and around the site provides vital planning intelligence to council authorities and your project team.
With the property’s hard infrastructure mapped out, let’s move on to documenting natural features…
Natural Features:
In addition to the built environment, a key part of site surveys is mapping natural elements like vegetation, watercourses and landforms. While man-made structures can be moved, natural features often pose valuable or protected assets that influence site layouts.
Your survey should outline the location, dimensions and types of significant trees and plants, whether preserved specimens, threatened species or weed infestations. Canopy extents, trunk positions and Tree Protection Zones will be delineated to guide building, excavations and landscaping around them.
Details like age, health, heritage classifications and nesting habits may also be captured for mature trees and vegetation precincts requiring protection during works. Recommended tree surgery like pruning or remedial treatments can be flagged if diseases or faults are noted.
Waterways like rivers, creeks or wetlands on or adjoining the property will be mapped including dimensions, banks, extents and buffered zones. Setbacks for building works may be required by authorities. Water sampling can also classify quality and habitats.
The survey will also highlight zones of environmental significance like heritage sites, erosion-prone areas or regions known to support endangered flora/fauna. Geotechnical hotspots can cover features like rock outcrops, unstable soils, mineshafts and landslip regions requiring further testing.
Capturing all valuable environmental assets early in planning stages allows appropriate site analysis by your design team. Refining placement of structures around natural elements avoids destroying important features or cost blowouts from unexpected discoveries later!
Finally, let’s cover documenting adjoining properties…
Adjoining Properties
Site surveys can’t just stop at the property boundary – they must document features of adjoining lots that could impact your development plans. This provides critical context on external influences like overshadowing, privacy or access issues that your project needs to accommodate.
The outlines, dimensions and uses of neighbouring buildings in proximity to shared boundaries will be shown on your survey plan, albeit in less detail than the principal structures on your actual site. However roof lines, exterior materials, window positions and overall height still need to be captured.
Sections of adjoining fences, walls or retaining structures along the perimeter should be depicted including height variations, materials used and condition. Encroaching elements like footings breaching the title boundary may affect demolition or digging works so are important to identify upfront.
Photos taken over fences can supplement drawings by revealing overlooked views enjoying vistas over your site. Alternately, intrusive sightlines down into private open spaces may demand screening solutions be incorporated in your design.
The position and height of existing trees near fences or boundaries should also be recorded as overhanging branches may require pruning if damaged during construction. Structural roots may likewise traverse underground across property lines requiring protection during excavations.
While the focus understandably rests on surveying assets within your site, adequately documenting external influences surrounding a property provides your team valuable context to make informed planning decisions from the outset.
Now that we’ve broadly covered what quality site surveys report, let’s examine some of the methods behind their precision…
The methodology
Behind every quality site survey is an array of sophisticated techniques and gear to precisely map your land’s features. But what goes into collecting reliable, benchmarked data you can count on? Let’s lift the veil on common survey methodology…
Licensed land surveyors use electronic total stations – essentially high-tech theodolites integrated with distance metres to track X,Y,Z coordinates in space. These tripod-mounted instruments employ mirrors, prisms and lasers to determine angles and distances to surveyed points accurate to within 3 mm tolerance.
Survey-grade GPS receivers can also classify locations to centimetre-level precision, helped by base stations transmitting local correction signals. Aerial drones may be used for supplementary top-down photography, helping map inaccessible spots while visualising height profiles.
Accurately determining relative vertical elevations relies on spirit levels and precise levelling procedures. Height differences are calculated from an established local datum point or Temporary Site Benchmark tied to the national coordinate system.
Land details are meticulously captured in specially coded field notebooks tracking coordinates, features, attributes and measurement methods adhering to strict survey standards. Reference marks are physically pegged on site allowing points to be accurately relocated later for setting out purposes.
Raw survey data is processed through specialised geospatial software suites to map boundaries, contours, infrastructure and land assets in 2D/3D as-built site plans. Modern robotic total stations and drones even support advanced reality capture, creating geo-referenced 3D site model flythroughs!
So while the tools have radically modernised, site survey principles continue following centuries-old measurement disciplines. Just don’t underestimate the technology and techniques delivering reliable site intelligence behind the scenes!
And that concludes our exploration of quality site survey essentials.