We’re committed to improving our ecosystems, quality of life, and communities for the better.
Our passion and commitment to the integration of innovative science and engineering drive us to exceed on behalf of every client.
Friends of Hopewell Valley Open Space (FoHVOS), in partnership with Princeton Hydro, has launched a groundbreaking initiative, “Monitoring Harmful Algal Blooms (HABs) in the Delaware River Watershed Using Drones and Spatial Analysis,” to improve understanding and forecasting of HABs throughout the Delaware River Watershed. Funded by the National Fish and Wildlife Foundation (NFWF), in partnership with the U.S. Fish & Wildlife Service, through the Delaware Watershed Conservation Fund (DWCF), the project leverages drone technology and advanced data modeling to identify environmental conditions that contribute to HAB formation and aims to develop tools and methodologies for early detection and management.
For this innovative research project, FoHVOS, a 501(c)3 and accredited Land Trust located in Hopewell Township, NJ, has teamed with Princeton Hydro. Princeton Hydro conceptualized and designed the initiative and is leading the technical implementation, including field survey design, drone operations, data analysis, and volunteer training.
“The Delaware River is central to Hopewell Valley’s identity. It shapes our way of life, supplies drinking water to 14.2 million people, shelters wildlife like the endangered Atlantic sturgeon, and offers abundant outdoor recreation,” said Jennifer Rogers, Executive Director of FoHVOS. “HABs were once confined to ponds and lakes, but since 2018, they’ve appeared in colder months and spread to streams and rivers. Though land trusts traditionally focus on land, HABs show how land use directly affects water. These blooms often stem from excess nitrogen and phosphorus washed into waterways during storms. Protecting water means restoring land. Our partnership with Princeton Hydro aligns perfectly with our mission. Together, we’re working to better understand and safeguard the Delaware River and its tributaries in both NJ and PA.”
HABs, caused by nuisance growth of cyanobacteria, can have detrimental effects on water quality and are a growing environmental concern nationwide. These blooms deplete oxygen levels, release toxins, and disrupt ecosystems, potentially posing serious risks to drinking water supplies and the health of wildlife, pets, humans, and local economies. Despite advances in environmental monitoring, predicting when and where HABs will occur remains a challenge due to the complex interplay of nutrient loading, temperature, and hydrologic conditions that can lead to rapid bloom proliferation.
To address these challenges, this newly launched initiative integrates drone-based remote sensing, field sampling, and spatial data analysis to collect and interpret detailed environmental data over a two-year period. The study spans multiple monitoring sites along a 73-mile stretch of the Delaware River in New Jersey and Pennsylvania, focusing on near-shore sections and 23 associated waterbodies. The first survey event began in August 2025.
Drones equipped with multispectral imaging systems capture high-resolution spatial data that is then integrated with digital platforms to link remote-sensing with the drone data and on-the-water collected data. The field-based water quality measurements are being collected by a team of trained community volunteers who are using phycocyanin fluorometer meters to measure concentrations of the photosynthetic pigment phycocyanin, which is produced primarily by cyanobacteria. Volunteers enter the data into a customized ArcGIS mobile-friendly survey. These combined datasets will be used to develop and validate predictive algorithms for both planktonic and benthic HABs under varying seasonal and hydrologic conditions.
The following photos depict the RGB (Visual) and corresponding Thermal image from the monitoring flights over Spring Lake in New Jersey:
“This research project represents a major step forward in how we study and manage harmful algal blooms at the watershed scale,” said Dr. Fred Lubnow, Project Lead and Senior Technical Director of Ecological Services at Princeton Hydro. “By integrating satellite data, drone imagery, and on-the-water sampling, we’re developing predictive tools that will enable us take a proactive approach to mitigate HABs, improve response time, and better support our ecosystem health.”
Project partners include New York City College of Technology – The City University of New York, which donated the drone and is supporting remote sensing and data integration; Trenton Water Works, Mercer County Park Commission, and The College of New Jersey which are providing monitoring sites and contributing volunteers for water quality data collection in New Jersey; Aqua-PA and the Philadelphia Water Department, which are providing monitoring sites and volunteers to collect watershed data in Pennsylvania; the Bucks County Conservation District, which is coordinating volunteer data collection; and Turner Designs, whose advanced phycocyanin sensors are being used to calibrate and validate drone-based monitoring data.
In the photos below, volunteers are being trained by Princeton Hydro staff on how to use phycocyanin fluorometers and Secchi disks to gather water quality data and log their findings.
This $1M project is funded through a $488,400 NFWF DWCF grant as part of the NFWF’s Research, Monitoring, & Evaluation Grant category and $513,700 in matching funds from project partners. This grant category aims to support high-performing science that is inclusive, adaptive, and innovative, with the potential to transform the Delaware River Watershed’s future through improved conservation, restoration, and public engagement.
Once complete, the project will produce a comprehensive report summarizing methods, analyses, and data-driven recommendations for practical, low-cost HAB monitoring and mitigation strategies that can be replicated across the Delaware River Watershed and beyond. Crucially, the report will identify tributaries and sources contributing to riverine HABs, enabling targeted restoration of the most affected lands and waters. Data collection will continue through Fall 2025, resume in Spring/Summer 2026, and culminate in a final report expected in 2027.
FoHVOS is a 501(c)3 nonprofit land trust dedicated to conserving the natural resources of the Hopewell Valley region and beyond. Through land preservation, ecological restoration, community engagement, and science-driven initiatives, FoHVOS works to protect and enhance open spaces for future generations. Learn more at www.fohvos.org.
Princeton Hydro is committed to improving our ecosystems, quality of life, and communities for the better. The firm was formed in 1998 with the specific mission of providing integrated ecological and engineering consulting services. Offering expertise in natural resource management, water resources engineering, geotechnical design and investigation, and regulatory compliance, their staff provide a full suite of environmental services throughout the Northeast for the public and private sectors. Project Lead, Dr. Fred Lubnow, is an expert in HAB management and has worked with dozens of lake associations and government agencies to restore lakes, manage watersheds, reduce pollutant loading, address invasive aquatic plants, and mitigate nuisance HABs. To learn more about Princeton Hydro’s work to mitigate harmful algal blooms, go here.
add comment
Δ
Your Full Name * Phone Number * Your Email * Organization Address Message *
By EmailBy Phone
Submit
Couldn’t find a match? Check back often as we post new positions throughout the year.
PRINCETON HYDRO
PRINCETON HYDRO