# Presentation: 472399

## How Science Can Inform CWA Jurisdiction and Policy After SWANCC:Hydrological Connectivity in Stream NetworksMark Cable Rains1 and Tracie-Lynn Nadeau21University of South Florida2U.S. Environmental Protection Agency

**How Science Can Inform CWA Jurisdiction and Policy After SWANCC:****Hydrological Connectivity in Stream Networks****Mark Cable Rains****1**** and Tracie-Lynn Nadeau****2****1****University of South Florida****2****U.S. Environmental Protection Agency**

## SWANCC(Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers)

- Key Issue – Can isolated waters be considered “waters of the United States” and thus be subject to Corps regulatory authority under CWA § 404 based solely on its use by migratory birds?
- Key Finding – No, the CWA is not intended to protect isolated, intrastate, non-navigable waters based solely on its use by migratory birds.
- Key Finding – Non-navigable, isolated, intrastate waters need a “significant nexus” to the physical, chemical, and biological integrity of navigable waters to be jurisdictional.

## Post-SWANCC Actions

- EPA and Corps decide against proposed rulemaking (December 2003)
- Corps Districts providing regional guidance without much national guidance
- Consultants providing guidance without much agency oversight
- Legislation (e.g., Federal Wetlands Jurisdiction Act of 2004)
- Litigation (e.g., *Rapanos *and *Carabell*)

## Special Session & Collection

- Special session at the American Water Resources Association 2005 Annual Meeting (November 2005)
- Special collection in the Journal of the American Water Resources Association (February 2007)

## Guiding Questions

- To what degree are headwater streams and downstream waters hydrologically connected?
- What roles do headwater streams play in maintaining the physical, chemical, and biological integrity of downstream waters and the larger stream networks?
- Over what spatial and temporal scales are processes relevant?
- What are some of the possible consequences of eliminating or otherwise impacting headwater stream resources?

## Special Collection

**Winter** - *The Role of Ground Water in Generating Streamflow in Headwater Areas and in Maintaining Baseflow*
**Izbicki** - *Physical and Temporal Isolation of Headwater Streams in the Western Mojave Desert, Southern California*
**Triska and others** - *Mississippi River Hypoxia: In the Beginning...*

## Special Collection

**Alexander and others** - *The Role of Headwater Streams in Downstream Water Quality*
**Wipfli and others** - *Ecological Linkages Between Headwaters and Downstream Ecosystems: Transport of Organic Matter, Invertebrates, and Wood Down Headwater Channels*
**Meyer and others** - *The Contribution of Headwater Streams to Biodiversity in River Networks*

## Special Collection

**Hauer and Stanford** - *Pattern and Process in Northern Rocky Mountain Headwaters: Ecological Linkages in the Headwaters of the Crown of the Continent*
**Freeman and others** - *Hydrologic Connectivity and the Contribution of Stream Headwaters to Ecological Integrity at Regional and Global Scales*
**Nadeau and Rains** - *Hydrological Connectivity Between Headwater Streams and Downstream Waters: How Science Can Inform Policy*

## Headwater Streams

## Headwater-Mainstem Continuum

- Hillslopes, headwater streams, and downstream waters are best described as individual elements of integrated hydrological systems
- No scientific evidence exists supporting the existence of a bright line separating headwater streams from downstream waters
- This implies that a “significant nexus” exists between headwater streams and navigable waters

## One size does not fit all....

**One size does not fit all....**

## Hydrologic Landscape Units

## Interacting and Cumulative Effects?

## Discussion....

**Discussion....**