Question 1

Do you use exclusively ultrasonic sensors or do you use other technologies, too?

Accepted Answer

Hohonu uses sensors of all types, including ultrasonic and radar. It has performed testing in partnership with NOAA at multiple sites throughout the US to verify accuracy of its monitoring system.

Hohonu has been built and deployed water level instruments comprised of temperature-compensated ultrasonic sensors (MaxBotix MB7388)(https://maxbotix.com/products/mb7388), traditional radar sensors (Hydromet OTT RLS)(https://my.hach.com/ott-rls-radar-level-sensor/product?id=59429665932#:~:text=The%20OTT%20RLS%20is%20a,easily%20connects%20to%20most%20dataloggers.), emerging radar sensors (Vega C22)(https://www.vega.com/en-us/products/product-catalog/level/radar/vegapuls-c-22), depending on the specific site, application, and customer budget. Full technical specifications are available for each following the links provided.

Hohonu adds on-board power & data management, telemetry to the cloud, automated Quality Assurance & Quality Control following NOAA QARTOD (https://cdn.ioos.noaa.gov/media/2021/04/QARTOD_WaterLevelManual_Update_V2.1_Final.pdf)standards, public access of custom visualizations via a web data portal and iOS app, and custom, site-specific predictive analytics that outperform federal forecast models. Hohonu’s fully documented onboarding procedures for new customers are freely available here.(https://hohonu.notion.site/Welcome-to-Hohonu-Onboarding-1b610dc3c8d54652abea15bed47dc8ec)

Question 2

Do you only deploy sensors for tidal purposes?

Accepted Answer

Absolutely not! We use the same technology to deploy inundation sensors that can detect flooding for low-lying infrastructure such as roads. You can learn more about our work in Boston by clicking here.(https://stonelivinglab.org/news-article/field-observations-real-time-data-from-the-january-13-2024-storm-and-flooding-in-boston/)

Question 3

Why use Hohonu if I can just work with a local research group? Isn't the hardware easy to make?

Accepted Answer

Hohonu was born out of the University of Hawai'i because there was demand it could not meet within the walls of a research lab. Its founding team all has research and academic backgrounds.

When working with a local research team to deploy sensors, we believe it is prudent to ask the below questions:
 • How will data telemetry, integration, and management be developed?
 • How will data be visualized and accessed? Can data be easily shared and understood by the general public? Will there be API documentation?
 • Will the resulting data management system be able to handle calculation of tidal datum's and sensor replacements? Will it adhere to NOAA standards for metadata management? 
 • What is the longevity of support? Does the team have other funded, competing projects that needs to be managed in addition to deploying these sensors?
 • How many sensors are needed? Does the team have the capacity to meet that volume while keeping quality and consistency high?

Question 4

In what ways can I access the data?

Accepted Answer

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: https://dashboard.hohonu.io/(https://dashboard.hohonu.io/)
    • TideCast iOS Mobile App : https://apps.apple.com/us/app/tidecast-by-hohonu/id6447706980
    • 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: https://hohonu.readme.io/reference/authentication(https://hohonu.readme.io/reference/authentication)

• 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

Question 5

How do you manipulate raw sensor data?

Accepted Answer

Hohonu strives for "no black boxes." Data at each step of the pipeline can be accessed via our dashboard and APIs, and our methodologies for data manipulation are well-documented and in accordance to NOAA standards (where applicable).

• Raw data
    • 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: Revised Hohonu QARTOD documentation(https://www.hohonu.io/_files/ugd/fb3fef_0e550ee3bb4e4dc88cf2e03c9788229f.pdf)
 • Reference systems / datums
    • D2W data converted to:
       • NAVD88 (if a survey was conducted)
       • MLLW / MHHW
          • Requires 35 days of installation data
 • 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 
 • Additional features
    • Custom high water thresholds
       • Each site can have high water thresholds assigned, with a text description of what each threshold means (e.g. top of bulkhead)
    • Text Alerting
       • Users can sign up for text alerts when water levels reach the custom high water threshold

Question 6

What options exist for outright buying vs subscription?

Accepted Answer

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.

Question 7

How is installation and maintenance done?

Accepted Answer

Field installation and maintenance typically takes place in 2 ways:
 • Customer installs and maintains the sensor themselves
 • A contractor is hired to perform installation and maintenance

What the process looks like
 • Ship device to 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 is needed or included?
 • Monitoring device is included
 • Mounting materials are not included but we do provide standard recommendations on our onboarding manual: https://hohonu.notion.site/Device-Setup-c1233842cfb54769806140509a91f50d
 • RTK GPS and related toolkits are not included, can be arranged by Hohonu
Who is expected to do this?
 • 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: https://hohonu.notion.site/Device-Setup-c1233842cfb54769806140509a91f50d(https://hohonu.notion.site/Device-Setup-c1233842cfb54769806140509a91f50d)
       • 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

Question 8

How are vertical control standards verified and maintained?

Accepted Answer

We collaborate directly with NOAA scientists on best practices for surveying. Link to our surveying best practices documentation is here: https://hohonu.notion.site/Field-Installation-cd29d2fbc9b549bba238aef410403cf8(https://hohonu.notion.site/Field-Installation-cd29d2fbc9b549bba238aef410403cf8)

The documentation includes multiple standard operating procedures that were developed through a collaborative, multi-institutional hyperlocal water level project led by SECOORA.

Question 9

What is real-world performance like?

Accepted Answer

Hohonu has deployed in over 130 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.

Data uptime and quality will vary by site. On a typical day, our newest-generation ultrasonic sensors capture data 98% of the time with 99% passing of QARTOD tests.

Question 10

What are the costs for your instrumentation and services?

Accepted Answer

$3000/year per sensor base price (for lowest-cost ultrasonic sensor based model).

Question 11

I'm applying for a grant and want to list Hohonu as a line item. Can you provide a paragraph about Hohonu I can include?

Accepted Answer

Absolutely! You can copy and paste the below text.

Hohonu provides actionable data and insights to protect communities from future flooding. Hohonu has helped resilient communities across 15 states and 130 locations capture 2 million hours of water level data.

You can see all of their active stations on their dashboard (https://dashboard.hohonu.io/)as well as their TideCast iOS app (https://apps.apple.com/us/app/tidecast-by-hohonu/id6447706980).

What Makes Hohonu Different
With Hohonu, communities don't need to be technical experts to capture, access, understand, and share real-time water level data.

They 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. More below.
    • Funding from Senator Schatz's office as part of a grassroots effort to restore Hawaiian fishponds across the state
    • Army Corps for dredging-related monitoring
 • 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, Moffatt & Nichol, Integral Consulting
 • Nonprofits
    • American Shore and Beach Preservation Association
    • Gulf of Maine Research Institute

Frequently Asked Questions