The short answer
Start by defining the change you care about, then pick one repeatable method and measure on a fixed schedule: drive reference stakes or pins, run an Emery-style beach profile with two graduated poles, take framed repeat photos from a photopoint, or pull shoreline positions from free satellite imagery. Log every reading with date, tide, and conditions, and compare month to month and after storms. Consistency beats precision.
Key takeaways
- Match the method to the signal: stakes for edge retreat, Emery profiling for seasonal sand change, repeat photos for communicating change, satellite data for regional trends over decades.
- Every method needs one fixed reference monument landward of the active zone, surveyed and photographed once, so later readings stay comparable year after year.
- Measure on a fixed schedule (monthly at low tide for beaches; quarterly plus after storms for bluffs) and record date, tide, weather, and storm events on every field sheet.
- Photos from fixed CoastSnap-style cradles or Pix Stix posts build a qualitative timeline that non-specialists understand and managers treat as a trustworthy record.
- Satellite shorelines (CoastSat, USGS series) are suited to decadal, multi-metre trends with roughly ten metres of accuracy, but cannot resolve fine local change.
- Draw conclusions only after several seasons or years, and label storm readings separately so a single event is not mistaken for a long-term trend.
Decide what change you actually need to see
Erosion monitoring starts with a question, not equipment. You might own a bluff property losing centimetres each year to retreat, manage a sandy beach that gains and loses sand seasonally, or represent a community that needs to know whether the high-water line is creeping landward over decades. These are different problems with different resolutions and time scales, and picking the wrong tool wastes effort.
As a rough rule, the slower and larger the signal you want to track, the longer and lower-tech the method can be. Long-term retreat of a metre or more per year is captured with stakes and photographs. Seasonal sand-level changes of tens of centimetres need a beach profile run regularly. If you only need to know whether erosion is accelerating at your site and roughly how fast, a single consistent method beats a precise but abandoned one.
Also decide who will use the data. Private notes can take any form, but if results go to a municipality, a coastal program, or a grant report, you will need documented protocols, tied-down reference points, and a tidy log. Established volunteer programs such as the Alaska coastal effort deliberately structured their methodology to a quality-assurance standard so that community-collected data would be accepted in official work plans.
Build the measuring site so readings stay comparable
Every method rests on one principle: measurements must come back to the same fixed frame each time. Choose a reference line or monument set well landward of where waves and storms reach — a buried post, a rebar pin, or a permanent survey marker — so the zero point does not itself move. Then lay out one or more transects running straight toward the water, perpendicular to the shore.
New Hampshire's volunteer program and Alaska's Stakes for Stakeholders follow this pattern: researchers install permanent markers and accurately survey them in once, tying position and elevation to a datum, after which volunteers only repeat the simple measurement. In Bristol Bay, tribal staff keep the stakes, add a time-lapse camera, and, where there is a beachfront, run Emery-style profiles. Because the monuments are georeferenced at installation, later data remain comparable year to year.
Practical tips: place markers where they will not be walked over, protect them from storm surge or snow removal, and record GPS coordinates and a photo so a lost marker can be re-established. You also need landowner permission to access and cross ground, as these programs emphasize.
Measure retreat with stakes and a tape
For bluff, cliff, or shoreline-edge retreat — the line where erosion advances inland — the cheapest method is a fixed stake plus a tape measure. Place a reference stake a known distance landward of the eroding edge, then periodically measure the distance from that stake to the current edge along the same bearing. As the edge moves closer to the stake, you have quantified retreat.
Set two markers on the same line so you can detect whether a single stake was disturbed, and measure in the same place and direction each time. Record the date, the measured distance, and whether a storm occurred since the last reading. Alaska's coastal-community program found this stake-and-photo combination cheap enough to spread from three to ten communities, and structured under an approved quality-assurance plan so results could feed formal monitoring workplans.
The limitation is that a stake gives a point measurement at one spot, not the shape of the whole shore. Erosion is rarely uniform, so spread several transects along the section you care about. Space them closely enough to catch localized slumping but not so tightly that the effort outweighs the value, and where a bank is already defended or heavily used, several transects will show where erosion is worst.
Profile the beach to see sand gain and loss
When the question is about sand volume — did a storm strip the beach, and is it recovering — a simple Emery profile gives a cross-section of the beach from dune or backshore to the water. Two graduated staffs and a sighting method let two people map elevation changes along a fixed transect without a surveyor's level or laser instruments.
The method works because an observer sights across the top of one rod to the horizon and reads the matching graduation on the other rod, walking the pair down the beach at a regular interval of a few metres. New Hampshire's Volunteer Beach Profiling Monitoring Program has used it on roughly a dozen to fifteen sites since 2017, with volunteers going out about monthly at the lowest low tides plus after storms. Repeated profiles across seasons reveal which beaches lose sand fastest and recover slowest, and ultimately indicate where beach nourishment would be most needed.
What you get from profiles is elevation along the transect and, when combined across the section, an estimate of sand gained or lost. That is more informative for sandy beaches than a single edge distance, but it demands steady hands and the discipline to repeat exactly the same line and horizontal spacing each visit. All profiles are tied to a surveyed monument and datum so they can be compared with one another and across years.
Let repeat photography do the watching
Photography is the fastest way to start and often the most compelling. A fixed photopoint — a post, bracket, or phone cradle bolted in a stable spot — forces every repeat image to be taken from the same place, in landscape orientation, at roughly the same time. Programs such as CoastSnap install stainless-steel cradles overlooking beaches and ask visitors to drop a phone in, shoot, and upload; others, like South Australia's Pix Stix, use a simple rest with an example photo so volunteers align each shot.
The value is a visual timeline: images show dunes losing or gaining vegetation, sand banks moving, a scarp cutting into the foredune after a storm, and slow recovery afterward. Taken at a fixed interval and matched to dates, the stack of images becomes a time-lapse that even a non-specialist can interpret and that managers trust as a record.
The limitations are real: a photo is qualitative, and the apparent shoreline in an image depends on tide and wave conditions that day. Record the date, time, and approximate tide, and always shoot from the exact same framing. Some councils combine photopoints with an automated fixed camera — for example, BeachStat on the Australian coast — to collect frequent, consistent imagery that software turns into shoreline position and beach width.
Scale up with satellite shorelines when you need the long view
For large or regional questions — whether a whole coastline is receding, or where along many kilometres the shoreline is changing fastest — free satellite imagery and open-source tools remove most of the field effort. The CoastSat toolkit downloads Landsat and Sentinel imagery through Google Earth Engine and extracts shoreline positions at sub-pixel accuracy; the U.S. Geological Survey has published shoreline series for entire states derived this way, back to the 1980s.
Be realistic about precision. CoastSat shoreline products commonly carry on the order of ten metres of root-mean-square error, and accuracy is worse near river mouths, inlets, spits, and other dynamic spots. That is excellent for detecting a multi-metre-per-year, decadal retreat trend and inadequate for catching a thirty-centimetre change at your property line. Satellite results should be seen as a regional layer to complement — not replace — on-the-ground stakes and profiles.
Practically, you register for a free Google Earth Engine account, define your region and date range, and let the tool return shoreline points per transect that you plot in GIS or a spreadsheet. If that feels technical, check whether your state geological survey or university already publishes satellite-derived shoreline layers you can simply download.
Put it into practice
One-sheet monitoring plan: method matrix plus field checklist
Build a monitoring plan that matches your budget and your question. Use the matrix to choose a primary method, then take the checklist to the field on every visit so readings stay comparable from season to season.
- Goal — edge retreat: choose stakes; seasonal sand change: choose an Emery profile; many kilometres: choose satellite data; communicating change: choose photopoints.
- Install one fixed reference monument landward of the active zone and record its coordinates and a photo.
- If the section is longer than your reach, lay out two to three transects perpendicular to the shore and note their bearings.
- Keep one schedule: monthly at low tide for beaches; quarterly plus after storms for bluffs.
- Each visit record: date, time, tide state, weather, date of last storm, and observer name.
- For stake sites: measure the distance from the fixed stake to the eroding edge along the same bearing and check a second stake has not moved.
- For Emery profiles: two graduated rods, a fixed transect, consistent spacing (for example, every 3 m), re-tied to the surveyed monument.
- For photopoints: landscape orientation, phone flat in the cradle, match the example photo, note date and tide, and upload with location.
- Keep one field log and one photo folder per site and back them up quarterly.
- Re-measure after any notable storm or flood and label that reading clearly.
- Once a year, compare readings to the first year and plot change to spot acceleration.
- If using satellite data, download your transects and remember that accuracy is about 10 m, so only decadal-scale trends are reliable.
Questions people ask
How often should I measure shoreline erosion?
For bluffs and eroding edges, quarterly readings plus a measurement right after any storm that visibly undercuts the bank will catch acceleration; monthly readings add little for a slowly retreating edge. For sandy beaches that gain and lose sand with the seasons, profile monthly at low tide, because a single reading per season can miss storm scouring or miss a fast recovery. Whatever cadence you choose, keep it achievable for a full year, because a useful long-term trend only appears after you cover at least a couple of seasons or years.
What is the cheapest way to start monitoring?
Fixed photopoints are essentially free: pick a stable post or tree, mark the exact camera spot, and photograph the same framing in landscape each visit, logging the date and tide. If you want numbers, a single reference stake plus a measuring tape gives a repeatable retreat distance for the price of a stake. Beach profiling needs two simple graduated rods (which programs such as New Hampshire's supply or volunteers build) and no surveying equipment. Only the satellite route is genuinely free of fieldwork, but it is a download-and-learn task rather than a hardware cost.
Do I need to worry about tides when I measure?
Yes. The apparent shoreline and the water edge move metres with every tidal stage, so readings taken at different tides cannot be compared as if they showed real erosion. Schedule measurements near the same tidal stage — low tide is the practical choice for beaches because the profile extends furthest — and record the tide state on the field sheet. The Emery-profiling program in New Hampshire schedules monthly visits at the lowest low tides for this reason. For bluff-edge distance, tide matters less, but the water line should still be noted.
How accurate are satellite-derived shorelines?
Satellite shoreline products such as the U.S. Geological Survey's CoastSat-derived series typically carry on the order of ten metres of root-mean-square error, and uncertainty grows near inlets, river mouths, capes, and spit ends. That accuracy is fine for detecting a regional trend of metres of retreat per year over decades and not fine for catching tens of centimetres of change at a single property. Use satellite data as a regional check, and keep stakes or profiles on the ground for anything that must guide an individual decision.
How do I tell a real trend from one bad storm?
A single storm can strip a beach or notch a bluff in a way that looks dramatic but may partly recover within months. Avoid drawing conclusions from one before-and-after pair. Keep measuring on your fixed schedule after the storm and through the next season, then compare the post-storm readings with the same period in earlier years. A genuine erosion trend appears as the baseline shifting persistently in one direction over repeated seasons; an isolated event shows up as a spike that later returns toward the earlier range. Log storm dates so you can label and interpret these excursions correctly.
Sources and further reading
Sources were checked when this page was generated. Confirm changing dates, rules and prices with the original publisher.
- New Hampshire Volunteer Beach Profile Monitoring Program (VBPMP): Implementation, Field Methods, and Data ProcessingNOAA Institutional Repository / New Hampshire Sea Grant
- CoastSnap beach monitoringNSW National Parks and Wildlife Service
- Monitoring our Coastlines (CoastSnap and BeachStat)Shellharbour City Council
- Erosion Monitoring in Bristol BayUniversity of Alaska Fairbanks, Adapt Alaska
- Pix Stix: A community photo-monitoring project tracking change along Yorke Peninsula's coastLandscape South Australia - Northern and Yorke
- Shifting Sands: Tracking the Changing Shape of Our Shore (Time and Tide Podcast)New Hampshire Sea Grant / University of New Hampshire
- Satellite-derived shorelines for the U.S. states of Oregon and Washington for the period 1984-2023, obtained using CoastSatU.S. Geological Survey, Pacific Coastal and Marine Science Center