This page contains links to the Middle Potomac River Watershed Assessment project’s reports, workshop materials, and webinars. Products are listed chronologically, starting with most recent.

Final Report with USACE modifications (April 2014) — Middle Potomac River Watershed Assessment: Potomac River Sustainable Flow and Water Resources Analysis

The MPRWA report was modified in April 2014 to accommodate edits requested by Army Corps of Engineers headquarters. A large section (5.2) of the original 2013 report was removed and put in a new Appendix (D). Summary text from several of the original appendices was copied into the report. Minor edits were made in a few places to clarify. The overall content of the two reports is essentially the same. The final, eleven appendices are now available for download*:

Appendix A — Large River Environmental Flow Needs Report
Appendix B — Water Withdrawals and Consumptive Use in the Potomac River Report
Appendix C — Compilation of Measured Stream Data (data sets available on request)
Appendix D — Application of ELOHA
Appendix E — Development and Refinement of Hydrologic Model
Appendix F — Flow Metric Testing
Appendix G — Stream Classification
Appendix H — Basin-Wide Hydrologic Alteration Assessment (Excel file with data)
Appendix I — Development of Stream Flow Alteration – Ecological Relationships
– Data for Generating Flow Alteration  (Excel)
– Conditional Probability Flow Alteration – Ecology Plots (PDF)
– Scatter Plots of Biometric Value Versus % Flow Metric Alteration (PDF)
– Pearson Correlations (Excel)
– Quantile Regression (Excel)
Appendix J — Stakeholder Engagement
Appendix K — Implementation Options
– Potomac Basin Comprehensive Water Resources Plan Concept Paper (PDF)
– Case Studies (Excel)

*For additional materials, please use the “Search” feature on our Publications page. Feel free to contact us if you need documents not found on our website.

Journal Publication (December 2013) — “A test of The Ecological Limits of Hydrologic Alteration (ELOHA) method for determining environmental flows in the Potomac River basin, U.S.A.” published in the Journal of Freshwater Biology, vol. 58, pp. 2632-2647. Contact ICPRB for an electronic copy.

Final Report (April 2014) — Middle Potomac River Watershed Assessment: Potomac River Sustainable Flow and Water Resources Analysis (10.4 MB)
The assessment consists of five distinct components: (1) a large river environmental flow needs assessment, (2) a projection of future water uses, (3) a stream and wadeable rivers environmental flow needs assessment using the Ecological Limits of Hydrologic Alteration (ELOHA) method, (4) a stakeholder engagement process, and (5) development of a concept or scope for a strategic comprehensive plan for watershed management.

Webinar (Jun. 21, 2012) – Findings and Lessons Learned
This webinar summarizes findings of the project’s multiple components and discusses the difficulties encountered in accomplishing the project objectives (lessons learned). A series of next steps are recommended.

Webinar (Feb. 23, 2012) – Modeling Future Streamflows
This webinar explores how land development and climate change might be expected to impact stream biota in five future scenarios. Maps show where flow impacts are most likely to occur in the river basin.

Workshop materials (Nov. 29-30, 2011) – Presentations and handouts for the Streams and Wadeable Rivers Environmental Flows Workshop. Available by request by contacting ICPRB.

Webinar (Oct. 27, 2011) – From Science to Management Applications
This webinar began with a quick review of flow alteration – ecological response relationships being developed for this project and then reviewed how similar relationships were developed and applied to water resources management in Michigan and Massachusetts. The examples from these two states provide some context with which to begin considering how flow alteration-ecological response relationships might be used for management in the Potomac basin.

Webinar (Sept. 8, 2011) – Quantitative Flow-Ecology Relationships, Part 2
The webinar reviewed key points about sources and methods used to develop component data for flow alteration-ecology relationship plots, showed results of tests done to verify flow model performance, showed how flow alteration-ecology plots are generated, and showed an example interpretation.

Webinar (July 15, 2011) – Quantitative Flow-Ecology Relationships, Part 1
The webinar focused on the variables and data sets being assembled to create flow alteration-ecological response relationships and the methodologies to be used to test those relationships.

Webinar (June 16, 2011) – Modeling Streamflows
The webinar focused on the project’s methodology for selecting subwatersheds and generating synthetic daily flow time series, from which flow alteration-biological health relationships will be derived.

Large River Report (May 13, 2011) – Potomac Basin Large River Environmental Flow Needs (10.5 MB)
The hydrologic needs of key flow-dependent species and communities in four segments of the mainstem Potomac River and two selected large tributaries are identified using a modification of the Ecologically Sustainable Water Management (ESWM) approach. Draft findings were presented at a September, 2010, workshop and this final report incorporates input provided by workshop participants. Included in the report also are recommendations for additional research, monitoring, and analysis to fill current information gaps and better define acceptable thresholds of hydrologic alteration from current conditions. The report’s Executive Summary only (0.2 MB) also is available.

Webinar (May 10, 2011) – Human uses of water: current and future demands and impacts on flows
This webinar provided estimates of future (to 2030) human demand for water in the Potomac basin and describes how the project team made those estimates. Those demand projections will be used later in this project to estimate changes to stream flow under various scenarios for future conditions.

Webinar (April 12, 2011) – Middle Potomac Watershed Assessment: Sustainable Flow and Water Resource Analysis
This is the first webinar in the six part series providing an introduction to the methodology being used for all steps in the project. An audio recording of the webinar, on CD, is available upon request.

Webinar (March 15, 2011) – Middle Potomac Watershed Assessment: Applications for Jurisdiction Water use Decision Making (audio available upon request)
This webinar provides a project introduction as well as a conceptual framework for how the results of this project can be applied to basin-wide water resources management. An audio recording of the webinar, on CD, is available upon request.

Fact Sheet (February 25, 2011) – Middle Potomac River Watershed Assessment Factsheet
A brief description of the Middle Potomac River Watershed Assessment project.

Workshop materials (September 22-23, 2010) – Large River Environmental Flow Needs workshop
At this two-day workshop, river experts discussed the environmental flow needs of the mainstem Potomac River below Harper’s Ferry, the mainstem Monocacy River and Opequon Creek, and the freshwater portion of the tidal Potomac. Participants worked to establish a hydrological baseline for the Potomac allowing for ecological considerations to be built into long-term water and land use planning decisions.

Webinar (September 9, 2010) – Potomac Basin Large River Environmental Flow Needs: Introductory webinar for workshop participants
This webinar introduced the 22-23 September workshop to workshop participants and announced a draft version of the Potomac Basin Large River Environmental Flow Needs report.

Webinar (September 29, 2009) – Middle Potomac River Watershed Assessment: Defining Environmentally Sustainable Flows
This kick-off webinar started a series of webinar presentations made about the Middle Potomac River Watershed Assessment project over the following two years.