Plants and animals need nutrients to survive. But when too many nutrients enter rivers, streams and the Chesapeake Bay, they fuel the growth of algae blooms and create conditions that are harmful for fish, shellfish and other underwater life. In fact, excess nutrients are the main cause of the Bay’s poor health.
While nutrients are a natural part of the Chesapeake Bay ecosystem, nutrients have never been so abundant in the environment. Before humans built roads, homes and farm fields, most nutrients were trapped and absorbed by forest and wetland plants. As these habitats were removed to accommodate a growing population, nutrient pollution to the Bay increased.
Almost all people and industries in the watershed—and even some outside of the watershed—send nutrients into the Bay and its tributaries. Nitrogen and phosphorous are the two nutrients of concern in the area. In general, these nutrients reach the Bay from three sources: wastewater treatment plants; urban, suburban and agricultural runoff; and air pollution.
Nutrients can also come from natural sources, like soil, plant material and wild animal waste.
Excess nutrients fuel the growth of harmful algae blooms, which:
Each year, the Susquehanna River provides the Chesapeake Bay with about 41 percent of its nitrogen loads and 25 percent of its phosphorous loads. For decades, three large reservoirs that sit behind dams located along the lower portion of the river have held back some of the nutrient pollution that would have otherwise entered the Bay. But recent studies have drawn attention to these reservoirs’ changing effectiveness as “pollution gates,” with special attention paid to the reservoir behind the Conowingo Hydroelectric Generating Station, or Conowingo Dam.
In 2012, the U.S. Geological Survey (USGS) reported that the reservoir behind the Conowingo Dam had lost its ability to trap sediment and attached nutrients over the long term.
In 2014, the Lower Susquehanna River Watershed Assessment (LSRWA) team released the results of its evaluation of sediment management options at the Conowingo Dam. It found:
While the sediment that can scour from behind the dam doesn’t take long to settle to the bottom of waterways, the nutrients that are attached to this sediment are released back up into the water column in dissolved form. Because nutrient pollution has a lingering effect on water quality, lowering both nutrient and sediment pollution upstream of the Conowingo Dam would benefit Bay health.
To learn more, visit Learn the Issues: Conowingo Dam.
For Chesapeake Bay restoration to be a success, we all must do our part. Our everyday actions can have a big impact on the Bay. By making simple changes in our lives, each one of us can take part in restoring the Bay and its rivers for future generations to enjoy.
To lower nutrient pollution in the Bay watershed, consider reducing the amount of pollution that can run off your property: install a green roof, rain garden or rain barrel to capture and absorb rainfall; use porous surfaces like gravel or pavers in place of asphalt or concrete; and redirect home downspouts onto grass or gravel rather than paved driveways or sidewalks. If you have a lawn to take care of, use fertilizers properly: do not use more than needed, and do not apply to dormant lawns or frozen ground. You can also reduce air pollution by walking, biking or taking public transportation, or using electric or manual lawn mowers and yard tools instead of gas-powered machines.
Humans have dramatically increased nitrogen in the estuary since the early 19th century, study finds
A family farm far from the Chesapeake keeps water clean for its community
Improving water quality and bringing back quail populations is a win-win with the Natural Lands Project
Sam Owings combined his experience as a farmer and developer to address agriculture runoff
Data show significant drop in nutrient and sediment loads
During the 2015 water year (October 2014 to September 2015), approximately 217 million pounds of nitrogen reached the Chesapeake Bay. This is below the long-term average of 335 million pounds per year. River flow averaged 41 billion gallons per day during this time, which is below the long-term average of 51 billion gallons per day.
During the 2015 water year (October 2014 to September 2015), approximately 9.8 million pounds of phosphorus reached the Chesapeake Bay. This is below the long-term average of 20 million pounds per year. River flow averaged 41 billion gallons per day during this time, which is below the long-term average of 51 billion gallons per day.
Computer simulations show that pollution controls put in place in the Chesapeake Bay watershed between 2009 and 2015 lowered nitrogen loads eight percent, from 283 million pounds in 2009 to 259 million pounds in 2015. Excess nitrogen is one of the leading causes of the Bay’s poor health, and reducing nutrient pollution will be critical to achieving our clean water goals.
These pollution loads were simulated using the Chesapeake Bay Program’s Watershed Model (Phase 5.3.2) and wastewater discharge data reported by watershed jurisdictions. These simulations were calibrated using monitoring data.
Computer simulations show that pollution controls put in place in the Chesapeake Bay watershed between 2009 and 2015 lowered phosphorus loads 20 percent, from 19.2 million pounds in 2009 to 15.4 million pounds in 2015. Excess phosphorus is one of the leading causes of the Bay’s poor health, and reducing nutrient pollution will be critical to achieving our clean water goals.
These loads were simulated using the Chesapeake Bay Program’s Watershed Model (Phase 5.3.2) and wastewater discharge data reported by watershed jurisdictions. These simulations were calibrated using monitoring data.
What is an algae bloom and how does it form? Charlie Poukish from the Maryland Department of the Environment explains what fuels algae blooms and how they can spell trouble for underwater life.
Decomposing algae blooms can suck oxygen out of the water, suffocating marine life and causing fish kills. In this follow-up to Bay 101: Algae Blooms, Charlie Poukish from the Maryland Department of the Environment documents a fish kill and explains how actions on land can affect life in the water.
Clear water is critical to underwater life. Bay grasses need sunlight to grow, and fish need sunlight to see. But what factors cause water clarity to fluctuate? Adam Davis from the Chesapeake Research Consortium explains, and uses a secchi disc to measure water clarity in Spa Creek.
Scientists from Maryland Department of Natural Resources and University of Maryland’s Chesapeake Biological Laboratory show us key methods for tracking nutrient levels and determining the health of the Chesapeake Bay.
Closed Captions: http://www.youtube.com/watch?v=U1prV3zpeZA
Publication date: June 01, 2009 | Type of document: Report | Download: Electronic Version
This report documents the calculations and procedures for the preparation of the input data to the Watershed Model - HSPF Phase 5. These calculations are used for creating the calibration data as well as scenario data. They form the basis…
Publication date: December 29, 2004 | Type of document: Report | Download: Electronic Version
In accordance with the requirements of the Clean Water Act (CWA) and the goals of the Chesapeake 2000 agreement, this paper describes an approach that the US Environmental Protection Agency Regions II and III (EPA) and Chesapeake Bay…
Publication date: December 01, 2003 | Type of document: Report | Download: Electronic Version
The Chesapeake 2000 agreement has been guiding Maryland, Pennsylvania, Virginia and the District of Columbia, the Chesapeake Bay Commission and the U.S. Environmental Protection Agency (EPA) in their combined efforts to restore and protect…
Publication date: June 01, 2003 | Type of document: Report | Download: Electronic Version
In developing revised water quality standards for the Chesapeake Bay and its Tidal tributaries, states may conduct use attainability analyses. This document provides economic analyses performed by the CBP related controls to meet revised…
Publication date: September 01, 2002 | Type of document: Report
Phosphorus plays a major role in nonpoint source pollution. It has become evident that agriculture is experiencing over-application of phosphorus, which has resulted in phosphorus enriched soils in certain locations. The Agricultural…
Publication date: April 10, 2002 | Type of document: Report
One of the Tidal monitoring and Analysis Workgroup's primary responsibilities is assessing and reporting the status and trends of nutrients and other parameters monitored within the scope of the Chesapeake Bay Program water quality and…
Publication date: August 01, 2001 | Type of document: Report
The report describes results from five sampling periods and examine the effects of atmospheric nitrogen deposition on changes in algal biomass, as well as major algal classes.
Publication date: June 19, 2000 | Type of document: Report | Download: Electronic Version
The phosphorus detergent ban was implemented in the Bay signatory jurisdictions in the mid to late eighties. After the ban's implementation, it became clear that the ban resulted in a significant reduction of discharge in phosphorus from…
Publication date: December 31, 1997 | Type of document: Report | Download: Electronic Version
This is a report on the status yields and trends of nutrients and sediment and methods of analysis for the nontidal data-collection programs in the Chesapeake Bay Basin
Publication date: January 01, 1997 | Type of document: Report
This report examines the cost effectiveness of control options which reduce nitrate deposition to the Chesapeake watershed and the tidal Bay. The object of the analysis is to determine the sources of atmospheric nitrate deposited to the…
Publication date: November 01, 1996 | Type of document: Report
Eutrophication -- low dissolved oxygen -- caused by excess nutrients, is the most significant water quality problem facing the Bay. The Chesapeake Bay Program jurisdictions have committed to reduce nitrogen and phosphorus pollution reaching…
Publication date: October 11, 1995 | Type of document: Report
This report summarizes the workshop proceedings which focused on atmospheric nitrogen compounds. Scientists in key policy and regulatory officials explored mechanisms by which air and water pollution control programs worked together to…
Publication date: June 01, 1993 | Type of document: Report | Download: Electronic Version
This document is intended to address the inconsistency between parts of the CBP in the sampling and analytical methodology for the determination of particulate concentrations, and offer alternative sampling and analytical procedures to be…
Publication date: January 01, 1993 | Type of document: Report | Download: Electronic Version
This report focuses on the identified need of the Chesapeake bay Program to better simulate nitrogen outputs from the forested portions of the Bay drainage and a short-term desire to the US EPA to be able to build off of the existing HSPF…
Publication date: June 01, 1992 | Type of document: Report
The primary purpose of this analysis is to determine whether selected lateral and mid-Bay stations in the Chesapeake Bay mainstem have the same overall levels of certain water quality parameters.
Publication date: February 01, 1992 | Type of document: Report
In this report, a comparison data set with helix and block results for the same samples was analyzed to estimate the magnitude of the low bias of the helix method compared to the block method.
Publication date: August 01, 1990 | Type of document: Report | Download: Electronic Version
As part of the Chesapeake Bay Agreement to which the State of Maryland is a signatory, several plants in Maryland will be required to reduce the nitrogen and phosphorus levels in their affluent. To examine the feasibility of biological…
Publication date: August 01, 1987 | Type of document: Report | Download: Electronic Version
This study was performed to compare standard EPA techniques for determining nitrogen and phosphorus concentrations in natural waters with oceanographic techniques typically employed by estuarine and marine scientists.