Water Quality Monitoring

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Tools to track progress towards improving water quality in the Severn River!

The Severn River gets pounded year round by a polluted mix of stormwater runoff that floods the river with nitrogen, phosphorus and sediment contaminants that combine to create algae blooms which then decompose and dilute the river of oxygen.

To track how our river responds to this pollution insult, volunteer citizen scientists have joined our fabled Water Quality Crew to create a 41-station network of monitoring stations.

Each week (May-October), our WQ Crew and Boat Captains create profiles of the water column in our river and creeks. They track dissolved oxygen, pH, temperature, salinity and clarity.

SRA is a Tier 2 data monitor with our partner, the Chesapeake Monitoring Cooperative.

You can view all this data on the Chesapeake Data Explorer. Click here to view our WQ data. (Note: You do have to drill down a bit to get to the Severn River monitoring stations.

During the summer of 2019, our WQ Crew started noticing very low oxygen levels in the Severn River, and this phenomenon was echoed inside many creeks. Good healthy levels of oxygen should normally be 5 mg/L or greater to keep our fish, crabs and oysters happy.

But we started finding oxygen levels well below this 5 mg/L level. Oxygen was falling to less than 2 mg/L in large areas of the river.

These low levels of oxygen create a dead zone – water with  little to no oxygen content. This can be fatal to fish, crabs and oysters. Some years, this dead zone area is limited to Round Bay. But in 2019, this dead zone extended from the Narrows to the foot of the Rt. 50 Bridge. It was a bit over 5 square miles, roughly the size of Denton, Md.

You can read SRA’s Mid-Summer Report, Tracking The Severn River’s Dead Zone by clicking here.

Add to this mix, fecal bacteria from pets, septic systems and wildlife, mud floods of sediment from uncontrolled construction sites, rapid development, loss of vegetation and tree cover and severe weather events that flood our waters with enormous levels of sediment and nutrient pollution.

The river faces a constant challenge from human activities and we’re already feeling the impacts of climate change, rising sea levels, and increased frequency and intensity of storms.

As rural areas turned suburban and then urban, the Severn lost its ability to bound back from these challenges. Instead, the river suffers from algae blooms, bacterial infestations, sediment and nutrient overloading during every rain event.

The picture at left is of silt plume in Luce Creek just after a heavy rain the night before. Culprit: A dirt-bike recreational area that lacks any best management practices to control stormwater runoff.

These factors that have created permanent, oxygen-depleted conditions in our river. Without oxygen, the fishery dies.

Fish and crabs swim and sidle away and leave our river. Oysters can’t swim away, so without oxygen, they suffocate in these conditions.

Result: The Environmental Protection Agency declared the Severn River an “impaired” waterway and imposed a “pollution diet” to reduce the flood of pollutants, primarily nitrogen, phosphorous and sediment.

How do we track progress? With a team of volunteer citizen scientists who help monitor 41 stations throughout the entire Severn River watershed. We visit these stations every week from May through October.


Track real data of actual conditions in the Severn River.

Computer modeling can only get to a best-guess of what conditions are like in a waterway.

The only way to really know whether we’re making any progress towards improving water quality – especially reducing the scale of the dead zones – is to collect water quality monitoring data from the river itself.

This is why the Severn River Association collects weekly data readings to paint a portrait of the water column at 41 locations along the 14-mile Severn River and its 39 creeks and coves.

The SRA water quality program was first created under the guidance of Prof. Andrew Muller in 2018. Prof. Muller, an Associate Professor of Oceanography at the U. S. Naval Academy, provided the initial training to a small team of citizen scientist volunteers who collected data from 8 stations in the top of the river.

Since then, SRA’s volunteers, dubbed the WQ Crew, have greatly expanded the initial program. They now visit 41 stations every week, from May through October throughout the entire river system.

The program collects basic water profile information: dissolved oxygen levels, salinity, pH, temperature and clarity.

Above is WQ Crew Team leader, Mackenzie, recording the data collected at our Marylanders Grow Oysters restoration reef at the foot of the Rt. 50 Bridge.

The photo at left is one of our volunteers, Steve from Annapolis, using a Seechi disk to measure clarity in Lake Ogleton.

SRA partners with the Chesapeake Monitoring Cooperative (CMC) to provide technical expertise, ensure quality assurance and collection control procedures for our water quality program and to provide a vehicle for sharing the data collected to the scientific community.

All the data collected by our WQ Crew is shared with the scientific community via CMC’s Data Explorer program that tracks water quality for the entire Chesapeake Bay watershed.

You can track all this work at the CMC’s Data Explorer website. Click here to view the data.


Severn River Association, Chesapeake Monitoring Cooperative, Operation Clearwater, Spa Creek Conservancy, Back Creek Conservancy, Anne Arundel Community College, Chesapeake Conservation Corps, Chesapeake Bay Trust and our volunteer boat captains and water quality crew.


Program Goal

Collect water quality monitoring data that tracks actual conditions in the Severn River water column

Program Outcomes

  • Collect high-quality data that reveals actual conditions in the Severn River water column
  • Raise public awareness about the condition of water quality in the river
  • Use data to support regulatory, policy and legal decisions designed to reduce pollution levels in the river and improve water quality
  • Support enforcement actions based on collection of top-quality water quality data
  • Create long-term record of water conditions
  • Produce annual report cards on the State Of The Severn River as a means of educating the public about progress towards restoring the river to fishable and swimmable goals of the Clean Water Act.

It’s easy to get involved with the water quality monitoring project. Volunteers are needed from May through October for weekly tours of the river.

For more information, email: