Beta Streamflow Duration Assessment Methods for the Northeast and Southeast
The beta Streamflow Duration Assessment Methods (SDAMs) for the Northeast and Southeast are scientific tools to provide a rapid assessment framework to distinguish between ephemeral, intermittent, and perennial stream flow at the reach scale for the for the Northeast and for the Southeast regions (not including the Caribbean). The User Manual provides instructions for implementing the beta SDAMs for the Northeast and Southeast to generate a streamflow classification, which requires entering data into an online tool.
The agencies are making these beta SDAMs available for a one-year preliminary implementation period to inform the refinement of the final SDAMs for the Northeast and Southeast. We welcome user comments during the preliminary implementation period.
On this page:
- What are the methods used for?
- How were the methods developed?
- Additional information on how to apply the methods
- Training opportunities
- Contacts
- Documents and tools
What are the Methods Used For?
Long-term hydrologic data to assess streamflow duration is often limited, especially for streams that do not flow year-round. SDAMs are rapid field assessment methods that use hydrological, geomorphological, and/or biological indicators, observable in a single site visit, to classify streamflow duration as perennial, intermittent, or ephemeral at the reach scale. Regulators and water resource managers can use rapid, reach-scale methods to determine streamflow duration classifications (i.e., perennial, intermittent, ephemeral) and to help implement many federal, state, and local programs.
For instance, this information could help determine whether a stream reach may be subject to jurisdiction under the Clean Water Act, although use of these methods are not a requirement for determining jurisdiction.
These methods are also useful where knowledge of streamflow duration improves ecological assessment, management, and decision-making.
While use of these methods may inform a more robust stream assessment, they were specifically developed to determine streamflow duration class and do not provide a stand-alone assessment of stream function or condition.
These methods do not alter or change the definition of Waters of the United States under the Clean Water Act.
How Were the Methods Developed?
Learn more about the development of streamflow duration assessment methods for nationwide coverage, including the steps for developing a regional method.
The beta SDAMs for the Northeast and Southeast result from a multi-year study conducted at 336 stream reaches across the Northeast and Southeast following the process put forward by Fritz et al. (2020). Forty candidate indicators expected to control or respond to streamflow duration were tested at sites of known flow duration class. Through statistical analyses, the agencies identified the subset of indicators with the highest diagnostic accuracy of flow duration classification and constructed the current data-driven beta methods. In October 2023 an error was found in the coding of the beta SDAM calculation of “at least intermittent” classifications. This error has now been corrected in the web application and in the November 2023 updates to the User Manual and supporting documents. Users of beta SDAMs that have received “at least intermittent” classification results prior to these updates should use the updated web application to correct possible errors in their classification results.
A supplemental document describing the data analyses as well as study data are available in the Documents and Tools section below.
Additional Information on How to Apply the Methods
The information below is intended to clarify how to apply certain elements of these methods. If you have other questions, feel free to share inquiries with contacts listed below.
1. How is the assessment reach defined for:
1.1 Unconstrained settings:
Assessments should be made over the length of a stream reach, rather than at one point. The assessment reach chosen should be representative of the stream and should have a length equivalent to 40 channel widths. For narrow streams, the length of the assessment reach should be a minimum of 40 meters. The agencies recommend walking the stream prior to choosing an assessment reach.
1.2 Constrained settings (e.g., within highway right-of-way or a single tax lot):
If it is not possible to assess a reach that is 40 channel widths in length, then apply the method for the entire length of stream that you can access. Make a note of your assessment reach length and constraints on the data sheet. If possible, inspect upstream and downstream sections of the stream and make a note of your observations.
2. Are the results from using these methods the same as a jurisdictional determination?
No. The regulatory agencies make jurisdictional determinations based on federal law and current guidance and policy, and method outputs are not a jurisdictional determination. Instead, these methods provide information that may be useful for the agencies to make timely decisions because they help determine streamflow duration.
3. Can these methods be applied to created or altered channels?
Yes, these methods can be used, in combination with best professional judgment, to assess the flow duration of created channels or stream reaches that have been highly modified. The agencies have observed that some hydrologic and biologic indicators tend to persist (wetland plants, for instance, may occur on the margins of the channel) even with frequent maintenance of the created or altered channels. When applying these methods in created channels or modified streams, note that the site is a “disturbed site/difficult situation” and describe it in the “notes.”
4. What part of the stream do I assess when working in a braided stream system?
Identify the lateral extent of the channels, based on the outer limits of the ordinary high water marks, and apply the selected method to that area as a whole. Some indicators may be present or more apparent in the main channel versus the side channels; note those differences on the field assessment form.
5. Are the methods applicable when a stream goes subsurface in a portion of the assessment reach?
Streams observed flowing subsurface during the assessment visit may flow on the surface during wetter times of the year; therefore, it is important to check the entire reach for indicators of streamflow. In addition, the accuracy of an assessment can be improved by conducting a follow-up visit during a wetter time of the year. Assessment reach placement should maximize the homogeneity of drivers of streamflow duration (e.g., valley morphology), and should not consider the presence or absence of surface water.
Training Opportunities
Contacts
User comments are welcome during the preliminary implementation period. Detailed instructions on how to provide comments are available in the Joint Public Notice of Availability.
EPA:
- (Region 1) Ray Putnam (putnam.raymond@epa.gov), 617-918-1523.
- (Region 2) Stephanie Andreescu (andreescu.stephanie@epa.gov), 212-637-3818.
- (Region 3) Christine Mazzarella (mazzarella.christine@epa.gov), 215-814-5756.
- (Region 4) Eric Somerville (somerville.eric@epa.gov), 706-355-8514.
- (Region 4) Kacy Sable (sable.kacy@epa.gov), 404-562-9346.
- (Region 5) Melanie Burdick (burdick.melanie@epa.gov), 312-886-2255.
- (Region 6) Chelsey Sherwood (sherwood.chelsey@epa.gov), 214-665-6452.
- (Region 7) Justin Kensinger (kensinger.justin.R@epa.gov), 913-551-7318.
Army Corps of Engineers:
- (Baltimore District) Matthew Gilbert, (Matthew.C.Gilbert@usace.army.mil) 412-295-2381.
- (Buffalo District) Peter Krakowiak (Peter.J.Krakowiak@usace.army.mil), 716-879-4363.
- (Charleston District) Jeremy Kinney (Jeremy.M.Kinney@usace.army.mil), 843-714-4649.
- (Chicago District) Andrew Blackburn (Andrew.J.Blackburn@usace.army.mil), 312-846-5543.
- (Detroit District), Sabrina Miller (Sabrina.M.Miller@usace.army.mil), 313-226-7495.
- (Fort Worth District) Joseph Shelnutt (Joseph.L.Shelnutt@usace.army.mil), 817-886-1738.
- (Galveston District) Mark Pattillo (Mark.E.Pattillo@usace.army.mil), 361-814-5847.
- (Huntington District) Wes Barnett (Wes.Barnett@usace.army.mil), 304-399-6905.
- (Jacksonville District) Jessica Cordwell (Jessica.L.Cordwell@usace.army.mil), 813-769-7067.
- (Kansas City District), Ryan Langer (Ryan.W.Langer@usace.army.mil), 816-389-3834.
- (Little Rock District) David Rupe (David.M.Rupe@usace.army.mil), 501-340-1386.
- (Louisville District) Patricia Grace-Jarrett (Patti.G.Jarrett@usace.army.mil), 502-919-0315.
- (Louisville District) Russell Retherford (Russell.L.Retherford@usace.army.mil), 812-853-0472.
- (Memphis District) Roger Allan (Roger.S.Allan@usace.army.mil), 901-544-3682.
- (Mobile District) Mike Moxey (Michael.B.Moxey@usace.army.mil), 251-694-3771.
- (Nashville District) Aric Payne (Aric.J.Payne@usace.army.mil), 423-394-5102.
- (New England District) Taylor Bell (Taylor.M.Bell@usace.army.mil), 978-318-8952.
- (New Orleans District) Jon Barmore (Jonathan.G.Barmore@usace.army.mil), 504-862-1704.
- (New York District) Tom Bruno (William.Bruno@usace.army.mil), 917-790-8516.
- (Norfolk District) Jeanne Richardson (Jeanne.C.Richardson@usace.army.mil), 434-384-0182.
- (Philadelphia District) Mike Leggiero (Michael.P.Leggiero@usace.army.mil), 570-842-1046.
- (Pittsburgh District) Alyssa Barkley (Alyssa.B.Barkley@usace.army.mil), 412-395-7209.
- (Savannah District) Justin Hammonds (Justin.A.Hammonds@usace.army.mil), 678-804-5227.
- (St. Louis District) Chad Lamontagne (Chad.M.Lamontagne@usace.army.mil), 314-331-8044.
- (Tulsa District) Rob Hoffman (Robert.B.Hoffman@usace.army.mil), 918-669-7481.
- (Vicksburg District) Bryton Hixson (Bryton.K.Hixson@usace.army.mil), 601-634-7550.
- (Wilmington District) Tyler Crumbley (Tyler.A.Crumbley2@usace.army.mil), 901-251-4170.
Documents and Tools
- Updated User Manual for a Beta Streamflow Duration Assessment Methods for the Northeast and Southeast of the United States (pdf)
- Updated Development and Evaluation of the Beta Streamflow Duration Assessment Methods for the Northeast and Southeast (pdf)
- Updated Online Web Application – an electronic application to obtain a streamflow duration classification based on user-submitted data; also provides users the option to generate a report of their results.
- Data used to develop the beta SDAMs for the Northeast and Southeast.
- Joint Public Notice announcing availability of the beta SDAM for the Northeast and Southeast (pdf)
- Review of Flow Duration Methods and Indicators of Flow Duration in the Scientific Literature: Northeast and Southeast of the United States (pdf)