Choose an Excellent Monitoring Site

A 6-point evaluation for reliable, trustworthy flood data

The data your flood and weather monitoring network produces is only as good as the sites you choose. A well-sited sensor delivers consistent, accurate readings you can act on with confidence — during everyday operations and during the critical moments when your data matters most.

Site selection is one of the highest-leverage decisions you make in a monitoring deployment, so invest the time up front to get it right. The right location sets your equipment up to perform at its best across every season, for years to come. Our 6-Point Site Evaluation gives you a structured way to assess any candidate location before you commit — so you can choose sites you'll be proud of.

  1. Sensor: best conditions for accurate readings

  2. Solar: keep sensor powered all day, all night and through storms

  3. Signal: reliable communications for reliable data flow

  4. Structure: sturdy structure for stability and accurate reporting

  5. Safety: safety above all for installation and maintenance

  6. Shelter: prevent damage

Sensor

Accurate data starts with picking a site that allows the sensor to measure environmental conditions without obstruction. Secondly, you want to pick the right range sensor for the site. Get these two things right, and you get higher confidence that sensor data reflects real conditions instead of distortions — giving you data you can trust for flood alerts, trend analysis, and reporting.

Different types of sensors require different operating conditions:

Water level sensors - non-contact

Non-contact sensors - both ultrasonic and radar — thrive when mounted directly above an open section of water. That’s because they send a pulse to the water’s surface and measure the amount of time for the pulse to be reflected back. Look for a location with a clean vertical sightline from a perpendicularly suspended sensor to the water straight below. Look out for obstructions like vegetation obscuring the water, rocks or debris, protruding parts of a bridge or dock structure, anything that may interfere in the sensor's conical beam.  Consider vegetation, debris or other obstacles that may appear under the sensor suddenly or over time. More powerful sensors can handle some interference, but the lower you go in price, the more you need a smooth unobstructed water surface to bounce a signal off of.

Height matters

Measure the distance from your planned mounting point to the water surface at both normal stage and expected low water stage. Water level sensors have different distance ranges. Use the distance from the mounting point to the water surface to select the model that covers the range you need to measure. 

Turbulence

What if your site has swirling currents, lots of waves, strong wind? Like a swift stream or an open bay or ocean? A radar sensor costs more, but it will give you more accurate and smoother data in these conditions than an ultrasonic sensor.

Dry land

What about measuring flood spots that are dry most of the time, like an intersection?  Both ultrasonic and radar can do the job here - as long as they can measure a flat surface,  like level ground or concrete or even a maintained lawn. Watch out for slopes, uneven surfaces, or tall/thick vegetation. And of course, anything that walks, drives, or gets parked under the sensor will be “seen” by the sensor - so pick a monitoring spot where that’s unlikely to happen.

Water level sensors - submersible

Submersible sensors, including pressure transducers, measure the volume of water above the sensor to gauge depth. They operate best in clean, clear, fresh water, the stiller the better. An advantage of submersible sensors is that they are unperturbed by vegetation or debris growing over the surface of the water. A big tradeoff is the cleaning and calibration required (the dirtier/saltier the water, the more frequently you’ll have to do this), and the risk of getting swept away during a flood.

Precipitation and weather stations

If you want to know how hard it’s raining or how hard the wind is blowing, you want to site your sensor in an open sky location where it won’t be sheltered from the full force of the rain or wind by obstructions like buildings or trees. A well-chosen open site captures true precipitation totals and representative wind/gust data without the distortions that nearby structures can create.

Solar

A monitoring station that never runs out of power is a monitoring station you can count on. Choosing a site with excellent solar exposure means your sensor keeps transmitting through cloudy stretches, short winter days, and peak summer heat — no gaps in your data record.

The best solar sites share a few characteristics worth actively seeking out:

  • An unobstructed southern exposure is the gold standard. Look for a site where the panel can face south with open sky from roughly 9 a.m. to 3 p.m. — that window reliably delivers the six or more hours of effective charging your system needs each day.

  • Evaluate the site across all four seasons, not just the day you visit. A location that's sunny and open in summer may be shaded by low winter sun angles competing with buildings or hills. A wooded location that seems sunny in winter can get shady when the spring leaves grow in. The best sites stay well-lit year-round.

  • Even when the structure's orientation isn't ideal, you may still be able to get enough sun with an east or west-facing solar panel.

Signal

Now that we have the sensor and power sorted, how will we transmit the data so we can use it? A site with strong, consistent connectivity ensures every reading arrives on time, every time, so your team always has a current picture of conditions.

Cellular communication

Cellular networks are popular because they are widespread, affordable, and flexible. Verify signal strength and quality from all three major carriers — AT&T, T-Mobile, and Verizon — directly at the candidate site. Green Stream devices use LTE Cat-M1 frequency, and will connect automatically to whichever carrier is strongest in the area. A location with good coverage from at least one of these carriers is all you need.

Cellular communication relies on line of site to a cell tower that has LTE Cat-M1 service (different frequency than your phone). 

The most reliable way to measure coverage? Take a reading on-site with a signal tracker. Less reliable: cellular coverage maps, or looking at the bars on your phone.

Satellite communication

Remote or low-signal locations are still excellent candidates for satellite connectivity. Identifying the need for satellite early in the evaluation process means you can select the right equipment and budget accordingly — turning a connectivity challenge into a solved problem. The best condition for satellite transmission is a clear sky view. Light tree canopy is okay. Heavy canopy works but may cause some spottiness in communication.

Structure

When your sensor equipment is anchored securely, above foreseeable flood levels, and on properly permitted infrastructure, you get years of reliable data from a single installation.

The best mounting situations combine stability, longevity, and clear permissions:

  • Solid, vibration-free infrastructure is your foundation. A solid structure that holds equipment secure and still keeps your sensor aimed exactly where it should be — reading after reading, year after year. Bridges, culverts, bulkheads and many docks/piers are great for positioning water level sensors over open, unobstructed water. Some utility posts may be suitable. Walls, fenceposts, flat roofs, or solid ground are best for precip/weather stations. Avoid structures that wobble or vibrate, are weak/rickety, or uneven. You can create infrastructure by setting a pole or post solidly in the ground/substrate.

  • Confirm ownership and permitting early! Many excellent monitoring locations — bridges, public waterways, highway right-of-ways — are accessible with the right permissions in place. Starting the permit process early, with the appropriate agency (DOT, Army Corps of Engineers, local government), keeps your deployment timeline on track.

  • Review 100-year and 500-year flood elevation data early. This helps you plan how high to position the equipment vertically. Mounting your sensor and enclosure well above projected flood levels means your system stays operational exactly when conditions are most extreme — and the data is most critical.

  • Think about long-term access. A mount that's easy to reach for routine maintenance keeps your monitoring program running smoothly without unplanned complications.

Safety

A monitoring site that's safe to access is a site your team can maintain confidently and consistently — ensuring your network stays in top condition.

Safe sites are key to sustainable monitoring:

  • Look for sites where technicians can work at a comfortable, stable position — solid footing, manageable heights, no unusual hazards. No leaning out, precarious balancing.

  • If wading is involved, favor shallow clear water with a sandy or pebbly bottom - not muck, branches, big rocks or hidden sharp objects.

  • Survey the natural environment as part of your evaluation. Ensure the area is clear of known wildlife hazards — whether mammal, reptile, insect, or plant.

  • On bridges and roadsides, favor slower traffic and wide workspace.  Carefully obey traffic safety regulations and plan traffic control service ahead of time if needed. This may be the most important safety observation.

  • Document site-specific safety notes so every team member who visits — not just the original installer — arrives prepared. Good documentation makes every visit safer and faster.

Shelter

By Shelter, we mean choosing a site that naturally shields your equipment from environmental damage — overgrowth, wildlife infestation, human interference or vehicle strikes. Protect your investment!  Look for sites that naturally work in your favor.

Open, maintained sites — mowed rights-of-way, cleared streambanks, paved areas — are excellent choices for deterring plant overgrowth.  When evaluating a site, picture it at the height of the growing season. 

How not to be a target of vandalism: Pick sites with low foot traffic, natural concealment, or where you can position the sensor out of easy reach (but still accessible for maintenance). If the sensor is to be installed in plain view/easy pedestrian access, consider signage that explains what the sensor is for and why it is there to protect the community.

Remember: Great Sites Produce Great Data

When a site scores well across all six dimensions, you have found something genuinely valuable: a location where your sensor can perform at its best, your team can work with confidence, and your data record can grow without interruption for years to come.

The investment you make in a careful site evaluation pays dividends every day your network is running — in data you trust, alerts you can act on, and a monitoring program your stakeholders can depend on.

Have a candidate site you'd like to talk through? The Green Stream team is glad to help you evaluate it. Reach out anytime — we love helping partners build monitoring networks they're proud of.