## Water: Ecoregions

The U.S. is divided into 14 distinct eco-regions.

I: Willamette and Central Valleys• II: Western Forested Mountains• III: Xeric West• IV: Great Plains Grass and Shrublands• V: South Central Cultivated Great Plains• VI: Corn Belt And Northern Great Plains• VII: Mostly Glaciated Dairy Region• VIII: Nutrient Poor Largely Glaciated Upper Midwest and Northeast• IX: Southeastern Temperate Forested Plains and Hills• X: Texas-Louisiana Coastal and Mississippi Alluvial Plains• XI: The Central and Eastern Forested Uplands• XII: Southeastern Coastal Plain• XIII: Southern Florida Coastal Plain• XIV: Eastern Coastal Plain (PDF)• You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more. You are here: Water Science & Technology Surface Water Standards & Guidance Water Quality Standards Water Quality Criteria Nutrients Ecoregional Criteria 

# Ecoregional Criteria

We publish recommended water quality criteria to reduce problems associated with excess nutrients in waterbodies in specific areas of the country. We work with states and tribes to adopt regional-specific and locally appropriate water quality criteria for nutrients in lakes, reservoirs, rivers, streams, and wetlands in fourteen ecoregions.


# Criteria Documents

Criteria Documents for Lakes & Reservoirs •

Criteria Documents for Rivers & Streams •

Ecoregional Criteria Document for Wetlands (PDF) (236 K) •
Summary Table for the Nutrient Criteria Documents (PDF) (68 K) July 2002 These tables present the recommended criteria for each of the aggregate nutrient ecoregions for the following parameters: Total Phosphorus, Total Nitrogen, Chlorophyll a, and Turbidity or Secchi. Criteria are presented for both Lakes & Reservoirs and Rivers & Streams. • 

## Page 1 of2 Ecoregional Criteria | Ecoregions | US EPA

2/13/2012 http://water.epa.gov/scitech/swguidance/standards/criteria/nutrients/ecoregions/index.cfmLast updated on Thursday, September 29, 2011 http://water.epa.gov/scitech/swguidance/standards/criteria/nutrients/ecoregions/index.cfm 

# History

We finalized nine water quality criteria documents for lakes and reservoirs, and rivers and streams. See below for documents and peer review comments.

Fact Sheet (PDF) (28 K) • Federal RegisterNotice (January 6, 2003) • Correction of significant figures for Aggregate Ecoregion I, X and XIII Nutrient Criteria Recommendations (PDF) (14 K) ◦
EPA Response to Peer Review Comments for Lakes and Reservoirs (PDF) (48 K) • EPA Response to Peer Review Comments for Rivers and Streams (PDF) (48 K) • Public Comments (PDF) (47 K) •
We solicited submissions of significant scientific information on nine nutrient water quality criteria documents for lakes and reservoirs, and rivers and streams.

Fact Sheet (PDF) (81 K) • Federal RegisterNotice (February 28, 2002) •
We published 17 ecoregional nutrient criteria documents for lakes and reservoirs, rivers and streams, and wetlands. See below for documents.

Fact Sheet • Federal RegisterNotice (January 9, 2001) • External Expert Peer Review Comments (PDF) (57 K) (June 2001) • Public Comments (PDF) (37 K) (June 2001) • 

## Page 2 of2 Ecoregional Criteria | Ecoregions | US EPA

2/13/2012 http://water.epa.gov/scitech/swguidance/standards/criteria/nutrients/ecoregions/index.cfm