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Frequently Asked Questions

Hohonu blends scientific rigor with community value and access


Read the most common questions in building water monitoring programs for a

single town and/or at a national scale

  • Do you have a mobile app?
    Yes! TideCast by Hohonu is the only iOS app with live tidal data from 400 Hohonu and NOAA locations and predictions from over 1,500 NOAA locations. How to Download TideCast by Hohonu: Search "Tidecast" or "Hohonu" in the iOS app store From your iPhone, click on this link: Android coming soon
  • What customers has Hohonu worked with?
    With Hohonu, communities don't need to be technical experts to capture, access, understand, and share real-time water level data. We make large-scale deployments possible by making it easy for sensors to be deployed, maintaining scientific rigor for the data to be trusted, and offering different ways for the data to be accessed. Federal Multiple offices within and adjacent to NOAA, including IOOS, Sea Grant, NERRS. We are working with the Southeast office of IOOS to deploy 50+ sensors in communities from Florida to North Carolina. Funding from Senator Schatz's office as part of a grassroots effort to restore Hawaiian fishponds across the state Municipal Municipalities from states that include Florida, South Carolina, Massachusetts, Maine, Washington, California, and more Emergency management, resilience offices, town planners, town administrators Environmental Consulting Firms Woods Hole Group and others Nonprofits American Shore and Beach Preservation Association Gulf of Maine Research Institute
  • Where have Hohonu instruments been deployed?
    Hohonu has deployed in over 100 locations in 15 states, from Alaska to Florida, and from Hawaii to Maine, in coastal marine, as well as inland lakes, streams, rivers, and reservoirs. Visit our deployments page to see all the places we've deployed.
  • Do you exclusively use ultrasonic sensors or do you use other technologies, too?
    Hohonu has been building & deploying water level instruments comprised of temperature-compensated ultrasonic sensors (MaxBotix MB7388), traditional radar sensors (Hydromet OTT RLS), emerging radar sensors (Vega C22), depending on the specific site, application, and customer budget. Full technical specifications are available for each following the links provided. Hohonu buys these off-the-shelf raw sensors, then adds on-board power & data management, telemetry to the cloud, automated Quality Assurance & Quality Control following NOAA QARTOD standards, public access of custom visualizations via a web data portal and soon-to-be-released iOS app, and custom, site-specific predictive analytics that outperform federal forecast models. Hohonu’s fully documented onboarding procedures for new customers is freely available here.
  • Do we need to pay a subscription or can we just buy?
    Hohonu offers environmental data as a service and does not sell hardware outright, but we are flexible in how invoices can be generated for multi-year projects that may have difficulty budgeting or accounting for annual subscription services. For our lowest-cost ultrasonic sensor, standard pricing is $3,000 / year / sensor. This includes all the sensor(s), software, data technologies that are required to capture and share water level data with your entire community. - Hardware leasing, free upgrades and replacements - Real-time data communications - Cloud storage - Online portal that is free for your entire community to use (if you choose), which includes text alerting - Quality-Assurance Quality-Control data filtering, built to NOAA standards - Tidal Analysis Datum calculators, built to NOAA standards - Water level predictions up to 5 days in advanced - API access
  • How do I access the data?
    Hohonu has developed multiple methods for accessing data, depending on the use-case and end-user experience level. Each method was developed with ease-of-use and accessibility in mind: For general and quick public access to real-time data: Web-Based Dashboard: iOS Mobile App (Android coming soon) HTML Widgets 2 lines of HTML code can be copy/pasted to generate a real-time water level graph on any website For advanced public users: CSV Downloads CSV reports can be downloaded directly from the web-based dashboard API Access Fully-documented API: For internal stakeholders to monitor hardware and network performance: Diagnostics viewer For validation of hardware performance before installation occurs Raw “Distance to water”, battery voltage, cell strength, standard deviation, and other parameters Status page For monitoring of network performance across each node Merging of operational metadata with ongoing performance on a site-by-site basis that is updated hourly Permissioned user access to display exclusively the stations that each partner cares most about - while protecting sensitive operational data Up-to-date operational plans for each station
  • Is the raw sensor data processed in any way? Do you provide access to both raw and processed data?
    Our standard ultrasonic sensors record "distance to water" samples at a 1Hz frequency. Data is packaged together over a defined time interval that is anywhere from 30 seconds - 6 minutes depending on battery level. Any data points outside of 3-sigma are thrown out and an "average" and "standard deviation" are transmitted to our servers. We offer customers complete access to both "raw" and "cleaned" data at every step of our pipeline via our API Raw data "Distance to water" (D2W) Standard deviation Other parameters such as battery voltage, cell strength and signal Processed QA/QC data “Cleaned” data following QARTOD methodologies, implemented over four years of collaboration with SECOORA, Axiom Data Science, and NOAA CO-OPS Complete documentation coming soon Reference systems / datum’s D2W data converted to: NAVD88 (if a survey was conducted) MLLW / MHHW Requires 35 days of installation data Consistent with NOAA's Tidal Analysis Datum calculator Complete documentation coming soon Near-Term Water Level Predictions 4-day water level forecasts, updated every 6 hours Adaptive analytics allow for increasing frequency of forecast updates during approaching storms or flood events
  • How is installation and maintenance properly handled if you don’t have someone on-site doing it yourselves?
    Support through an installation typically looks like: Hohonu ships a sensor to a customer Remotely assist with entire installation process Verify device performance before installation Review site selection options based on defined criteria Closely monitor performance directly after installation On a daily basis, review network performance and flag problematic stations with station owners Actively outreach to station owner, recommending initial troubleshooting and debugging methods based on received data Continue to troubleshoot and debug until the station is working again If needed, ship a replacement device At no extra charge What materials are included? Sensor is included Mounting materials are not included but we do provide standard recommendations on our onboarding manual: RTK GPS and related toolkits are not included, but can be arranged by Hohonu Who is expected to do the install? The identified Local Point of Contact is expected to: Install the device Physically receive the device and place it outside in the sun to charge Verify performance before it is installed Choose a site that satisfies selection criteria outlined on our manual: Install the device using our recommended procedures If surveying: To use approved equipment or approved vendors to perform the GPS survey, according to IOOS-approved methodology Register the device with Hohonu so that the data can be publicly displayed Be available for ongoing maintenance events Have access to the installation site in case troubleshooting or replacements are needed At what point does the company not provide support any more? Hohonu does not provide further support if: The customer is unresponsive for a non-functioning sensor for a period of 60 days There are no sites in the local area that provide data that meet Hohonu’s data standards In this case, the customer can be refunded
  • How are vertical control standards verified and maintained?
    Link to our surveying best practices documentation The documentation includes multiple standard operating procedures that were developed through a collaborative, multi-institutional hyperlocal water level project led by SECOORA.
  • Where can I see pictures of installations?
    Installation pictures can be found HERE and on our documentation page.
  • Do you offer your services anywhere in the United States?
    Yes, we offer our services in all 50 states. For international inquiries please inquire using our Contact page.
  • How does the sensor transmit data?
    95% of our devices leverage a trusted IoT platform that uses cell networks to transmit data in real-time. We also have experience with other protocols such as Xbee, LoraWAN, and satellite. Please contact via our Contact page if you'd like to learn more.
  • Do I need external power at the installation site?
    No. Our devices are completely solar-powered and do not require external power - other than the sun.
  • What has the real-world performance of your sensors been like?
    As of October 30, 2023: Total Number of Active Stations: 87 stations Total Hours Monitored Since 2021: 1,338,554 hours Last 30-Day Median Active Uptime: 94.40%
  • Do you offer discounts?
    Yes. Our most common discounts are for bulk orders, multi-year contracts, and nonprofits. Please contact us for more information.
  • What are the limitations to the instruments or locations deployed and are there adaptations to overcome these?
    There is a continuum of pros and cons between a NOAA NWLON station that can approach $500k to install and a high school robotics team DIY water level sensor that may cost a few hundred dollars in parts to assemble. Hohonu engages early with clients to discuss and implement the best fit between specific sensor selection and desired application, based on community needs, and decades of expertise in experimental design and ocean observing technology. Generally, for open-ocean exposed sites, or storm-hardened applications, radar sensors are recommended, whereas for many (most) applications, the lower cost temperature-compensated sensors are entirely appropriate, and often allow for a greater density of sensors to be deployed, providing actionable insight to flooding spatial variability questions that are emerging as top priorities for coastal communities as effects from climate change accelerate in frequency and intensity.
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