Delaware Estuary Water Quality Monitoring Program
Introduction

Initiated in 1967, DRBC's Delaware Estuary Water Quality Monitoring Program (aka the Boat Run) is one of the longest running monitoring programs in the world.

Each year, DRBC contracts with the Delaware Dept. of Natural Resources and Environmental Control (DNREC) to collect surface water samples in the Delaware Estuary, from the head of tide at Trenton, N.J. to the mouth of the Delaware Bay.

Samples are collected at 22 stations to manage water quality and ensure that criteria are being met. Currently samples are collected from March - October.

This monitoring program provides accurate, precise and defensible estimates of the surface water quality of the Delaware Estuary and allows assessment of water quality criteria compliance. 

Sample analysis includes:

  • Dissolved Oxygen, pH, temperature, specific conductance, turbidity, secchi depth, PAR
  • Nutrients (ammonia, nitrate + nitrite, phosphorus)
  • Sodium, chloride, chlorophyll-a
  • Bacteria
  • Metals
  • 1,4-Dioxane

Bacterial sampling results for fecal coliform and enterrococcus are posted below.

Other data are inputted into the U.S. EPA's Water Quality Portal, which is available to the public.

Map of Sampling Locations

Map of the Monitoring Sites for the Delaware Estuary Boat Run.
Delaware Estuary Water Quality Monitoring Program: Bacterial Data

Typically, once monthly from March to October, bacteria samples are collected at the 22 stations. Fecal coliform and enterococcus bacterial data (unit of measurement is cfu/100mL) are used to determine compliance with the Commission's water quality standards for recreational use. Learn more.

DRBC's bacterial water quality criteria standards are based upon the average of several samples over a period of time. While individual samples taken on a single day such as those reported here may exceed the number listed under the standard column, the standard is not violated until the average of multiple samples within a Water Quality Management Zone exceeds the standard value. Bacterial data are highly variable, and individual sample exceedances commonly occur following rainfall events due to non-point source runoff and discharges from combined sewer overflows.

Most Recent Bacterial Sampling Data: October 2024

Sampling
Site
River
Mile

10/7/24 Enterococcus
Enterococcus
Std.

10/7/24
Fecal Coliform

Fecal
Coliform
Std.
Trenton
131.04
30
33
160
200
Florence
122.4
 15
33
51
200
Burlington
Bristol Br.
117.8
9
33
55
200
Torresdale
110.7
 14
33
110
200
Betsy Ross Br.
104.75
5
88
93
770
Benjamin
Franklin Br.
100.2
11
88
>600
770
Navy Yard
93.2
7
88
150
770
Paulsboro
87.9
6
88
58
770
Eddystone
84.0
10
88
120
770
Marcus Hook
78.1
6
35
150
200
Oldmans Pt.
74.9
17
35
100
200
Cherry Island
71
 52
35
93
200
New Castle
66.0
36
35
63
200
Pea Patch Is.
60.6
23
35
83
200
Reedy Island
54.9
10
35
 37
200
Liston Pt.
48.2
4
35
33
200
Smyrna River
44.0
5
35
28
200
Ship John Light
36.6
ND
35
3
200
Mahon River
31.0
ND
35
1
200
Elbow of
Crossledge
Shoal
22.75
ND
35
ND
200
South of Joe
Flogger
Shoal
16.5
ND
35
ND
200
South Brown
Shoal
6.5
1
35
ND
200

If results are flagged with the indicator "QC," the calculated precision between the analytical and duplicate results is outside the quality control limit for this test.

For additional details, contact John.Yagecic@drbc.gov.

n/a = data not available
ND = non-detect

2024 Data
Data Explorer

DRBC staff developed an interactive application that allows the user to explore water quality data collected from the DRBC Delaware Estuary Water Quality Monitoring Program (aka the Boat Run) since 1999.

Check out the Data Explorer