Biomonitoring Program
About DRBC's Biomonitoring Program
DRBC staff perform biological monitoring of the Delaware River. Photo by DRBC. 
DRBC staff perform biological monitoring of the
Delaware River. 
Photo by DRBC. 

The DRBC's non-tidal Delaware River Biomonitoring Program surveys sediment, rocks, algae, aquatic insects and water chemistry at 25 sites throughout the non-tidal 200 miles of the Delaware River from Hancock, N.Y. to Trenton, N.J.

Data from this program provide a complete overview of the diversity and health of the aquatic life community and overall water quality of this stretch of river, which is protected by DRBC's Special Protection Waters (SPW) regulations.

Learn more about SPW

Samples are collected every three to five years, typically during August and September, targeting the richest habitat areas of riffles, runs or island margins.

At each site, a variety of biological parameters are assessed:

•  Diversity and health of the benthic (bottom-dwelling) aquatic life community, including macroinvertebrates (aquatic insects) and periphyton (algae);

•  Habitat characteristics;

•  Nutrients and Water chemistry (e.g., dissolved oxygen, temperature, pH and chlorophyll-a);

•  Diversity and health of fisheries, aquatic plants and freshwater mussels; and

•  Occurrence of invasive species, both aquatic and riparian plants and animals.

Monitoring SIte Locations for DRBC's Biomonitoring Program. Map by DRBC.
Monitoring Site Locations for DRBC's Biomonitoring Program. Map by DRBC.
View larger map (pdf)

Samples are analyzed by the Academy of Natural Sciences of Drexel University in Philadelphia, Pa.

Data assessed are included in the Delaware River Water Quality Assessment Report that DRBC develops every other year for the U.S. EPA.

Macroinvertebrates are collected from the Delaware River on a net and are identified and counted by DRBC staff. Photo by DRBC. DRBC staff collect a periphyton sample as part of its biomonitoring program. Photo by DRBC. DRBC staff collects a flow sample from the Delaware River as part of its biomonitoring program. Photo by DRBC.
Macroinvertebrates are collected from
the Delaware River on a net and are
then identified and counted by DRBC
staff.
Photo by DRBC.
DRBC staff collect a periphyton sample
as part of its biomonitoring program.
Photo by DRBC.
DRBC staff collects a flow sample from
the Delaware River as part of its
biomonitoring program.
Photo by DRBC.

In 2021, weather and high flows in the later summer prevented DRBC from completing its data collection; only the Lower Delaware sites were completed.

In 2022, the remaining 17 sites in the Delaware Water Gap and Upper Delaware will be assessed, weather and flows permitting.

Macroinvertebrates
DRBC staff collect and examine a macroinvertebrate sample from the Delaware River. Photo by DRBC. 
DRBC staff examine a macroinvertebrate sample collected
from 
the Delaware River. Photo by DRBC. 

Good Bugs Mean Healthy Rivers

Benthic macroinvertebrates are the main biological annual indicator assemblage monitored by DRBC and most other regulatory agencies. 

As stated above, benthic means bottom-dwelling. Macro means you can see with the naked eye (no microscope needed). Invertbrates are creatures without backbones.

Examples of benthic macroinvertebrates include aquatic insects, worms, crayfish, clams and snails. 

Analysis of macroinvertebrate communities to determine water quality is reliable and commonly used because:

•  They are abundant in most streams and are relatively easy and inexpensive to sample;

•  They are sensitive to environmental impacts;

•  They are less mobile than fish, and thus cannot avoid discharges, spills, etc.;

•  They are also able to detect non-chemical impacts to the habitat, such as siltation or thermal changes; and

•  They bioaccumulate many contaminants, so that analysis of their tissues is a good monitor of toxic substances in the aquatic food chain.

Because of these reasons, studying macroinvertebrates helps provide an overall picture of water quality at a particular site.

Finding species that are sensitive to pollution is an indicator of good water quality.

The DRBC plans to develop and initiate a long term, basin-wide tributary macroinvertebrate monitoring program in order to monitor trends in macroinvertebrate community composition on a basin-wide scale.

Currently, the DRBC monitors the mainstem Delaware River and uses data collected by the basin states for the tributaries. These data are analyzed using varying methodologies, which can be difficult to compare.

Learn More:

Periphyton
DRBC staff collect periphyton data. Photo by DRBC. 
DRBC staff collect a periphyton sample. Photo by DRBC. 

Algae that Tells a Story

Because the Delaware River is generally wide, shallow, clear and exposed to full sunlight, benthic periphyton are the river's dominant source of primary production.

Periphyton are sampled and monitored as an additional biological monitoring assemblage.

Examples of periphyton include diatoms and soft algae growing on rocks.

Periphyton are excellent indicators of short-term water quality changes, capable of providing biological signals for numerous pollution and habitat impacts; for example, eutrophication, salinity, ions, pH and sedimentation. 

DRBC began surveying Delaware River benthic periphyton in a 2005 pilot study, launching full-scale periphyton monitoring in 2006. 

Samples are co-located with the 25 benthic macroinvertebrate river survey sites and numerous special study sites on larger tributaries to the Delaware River. 

Methods can be found in the 2014 QAPP, linked above. 

These data will help assess general short-term Delaware River water quality and nutrient pollution impacts upon aquatic life.

 

Learn More:

•  Pilot Study: Implementation of a Periphyton Monitoring Network for the Non-Tidal Delaware River (pdf 1.7 MB; 2007)

•  Nutrient Enrichment Study Data from the Upper, Middle, and Lower Sections of the Non-Tidal Delaware River – 2009 (link to USGS site for report)

Related Resources

State of the Basin 2019:

Biomonitoring Program Specifics:

See the DRBC Biomonitoring Team in Action:

Other DRBC Biological Studies:

Invasive Species: