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Nutrients

Overview

Nutrients are chemicals that plants and animals need to grow and survive. When too many nutrients make their way into local rivers, streams and the Bay, they can create conditions that are harmful for blue crabs, bay grasses and other underwater life. Excess amounts of nitrogen and phosphorus, two types of nutrients, are the main cause of the Bay's poor health.

Where do excess nutrients come from?

Virtually all people and industries in the Bay's seven-jurisdiction watershed — and even some beyond the watershed — contribute nutrients to the Bay and its tributaries. In general, excess nutrients reach the Bay from three major sources: specific, identifiable entry pipes; runoff from the land; and air pollution.

  • Wastewater treatment plants contribute the majority of nutrients that enter the Bay through specific, identifiable entry pipes. Wastewater plants release treated water — often still containing large amounts of nutrients — into local streams and rivers, which eventually flow to the Bay.
  • Nutrients that run off the land — including farmland and urban and suburban areas — come from a number of sources, including fertilizers, septic systems, boat discharges and farm animal manure.
  • Air pollution from vehicles, industries, gas-powered lawn tools and other emitting sources contribute nearly one-third of the total nitrogen load to the Chesapeake's waterways. Airborne nitrogen is contributed to the Bay region from an enormous 570,000-square-mile airshed that stretches north to Canada, west to Ohio and south to South Carolina.

Nutrients also come from a number of natural sources, including soil, plant material, wild animal waste and the atmosphere.

Nutrients have always been a part of the Bay ecosystem, but not at the excessive levels found today. Prior to significant human activity in the region, most nutrients were absorbed or held in place by natural forest and wetland vegetation. As forests and wetlands were replaced by farms, cities and suburbs to accommodate a growing population, nutrient pollution to the Bay has vastly increased.

How are excess nutrients a pressure on the Bay?

Excess nutrients fuel the growth of dense algae blooms that:

  • Block sunlight that underwater bay grasses need to grow. Bay grasses provide food for waterfowl and shelter for blue crabs and juvenile fish.
  • Rob the water of oxygen, which crabs, oysters and other bottom-dwelling species need to survive.

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Chesapeake Bay News

In The Headlines


Nitrogen Loads and River Flow to the Bay

Approximately 269 million pounds of nitrogen reached the Bay during the 2012 water year, which is below the 1990-2012 average load of 343 million pounds. The 2012 load is 218 million pounds less than the 2011 load. The 2011 load of 487 million pounds was the third highest load during the 1990-2012 period.

Annual average river flow to the Bay during the 2012 water year was 51.7 billion gallons per day (BGD), which is below the 1990-2012 mean flow of 53.5 BGD. The 2012 flow is 21.3 BGD less than the 2011 flow. The 2011 flow of 73 BGD was the fourth highest flow during the 1990-2012 period.


Phosphorus Loads and River Flow to the Bay

Approximately 13.1 million pounds of phosphorus reached the Bay during the 2012 water year, which is below the 1990-2012 average load of 21.2 million pounds. The 2012 load is 50.2 million pounds less than the 2011 load. The 2011 load of 63.3 million pounds was the highest load during the 1990-2012 period.

Annual average river flow to the Bay during the 2012 water year was 51.7 billion gallons per day (BGD), which is below the 1990-2012 mean flow of 53.5 BGD. The 2012 flow is 21.3 BGD less than the 2011 flow. The 2011 flow of 73 BGD was the fourth highest flow during the 1990-2012 period.

 

Publications

Estimates of County-Level Nitrogen and Phosphorus Date for Use in Modeling Pollutant Reduction

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…

2011 Milestones to Reduce Nitrogen and Phosphorus

Publication date: May 12, 2009 | Type of document: Report | Download: Electronic Version

2011 Milestones to Reduce Nitrogen and Phosphorus

NPDES Permitting Approach for Discharges of Nutrients in the Chesapeake Bay Watershed

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…

Setting and Allocating the Chesapeake Bay Basin Nutrient and Sediment Loads: The Collaborative Process, Technical Tools and Innovative Approaches

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…

Economic Analyses of Nutrients and Sediment Reduction Actions To Restore Chesapeake Bay Water Quality

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…

Recommendations for Coordinating Phosphorus Based Nutrient Management Policies in the Chesapeake Bay Region

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…

Benchmarks for Nitrogen, Phosphorus, Chlorophyll and Suspended Sediments in Chesapeake Bay

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…

Effects of Atmospheric Nitrogen Deposition on Algal Assemblages in Chesapeake Bay

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.

The Phosphorus Detergent Ban

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…

Status Yields and Trends of Nutrients and Sediment and Methods of Analysis for the Nontidal Data-Collection Programs, Chesapeake Bay Basin

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

Nitrogen Oxides: Impact on Public Health and the Environment

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…

Atmospheric Nitrogen Deposition Loadings to the Chesapeake Bay: An Initial Analysis of the Cost Effectiveness of Control Options

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…

Managing Nutrients to Prevent Pollution

Publication date: September 01, 1996 | Type of document: Report | Download: Electronic Version

Nine action recommendations derived from a 1996 nutrient conference are addressed.

Airsheds and Watersheds - The Role of Atmospheric Nitrogen Deposition

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…

The advantages of Measures of Particulate Carbon, Nitrogen and Phosphorous by Direct Analysis.

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…

DRAFT- Nitrogen Outputs from Forested Watersheds in the Chesapeake Bay Drainage Basin

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…

Trends in Nitrogen in the Chesapeake Bay, 1984-1990

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.
 

Adjusting Helix Kjeldahl Nitrogen Results: Maryland Chesapeake Bay Mainstem Water Quality Monitoring Program

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.

Biological Nitrogen and Phosphorus Removal in Oxidation Ditches and High Nitrate Recycle Systems

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…

Nitrogen and Phosphorous Determinations in Estuarine Waters: A Comparison of Methods Used in Chesapeake Bay Monitoring.

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.




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From Around the Web

Bay FAQs

  • Why do scientists monitor phytoplankton?
  • What causes poor water clarity?

 

Bay Terms

  • Airshed
  • Algae bloom
  • Nutrients

 

Bay-Friendly Tips

  • Test Your Soil
  • Test your soil to determine how much fertilizer your lawn needs (if any at all) and the best time to apply it.
  • Reduce Emissions
  • When possible, walk, bike or take public transportation to reduce vehicle emissions that can pollute our air and water.
  • Reduce Emissions
  • Avoid letting your car idle. Idling for even 10 seconds can waste fuel, damage your engine and pollute our air and water.
  • Don’t Overapply Fertilizer
  • Use only the amount of lawn fertilizer you need. Twice the product won't make your lawn twice as green!
  • Reduce Polluted Runoff
  • Wash your car on grass or gravel rather than pavement so soapy, grimy wash water won't run off your property.
  • Pick Up Pet Waste
  • Pick up after your pet. Pet waste contains nutrients and bacteria that can wash into local waterways if left on the ground.
  • Fertilize in the Fall
  • If you need to fertilize your lawn, do it in the fall. Spring rains wash fertilizer off lawns and into local waters.

 

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