Project Number: 5020-12130-004-013-I
Project Type: Interagency Reimbursable Agreement
Start Date: Sep 1, 2021
End Date: Jul 30, 2026
The general objective of this two-phase project is to discern the potential contribution of legacy P sources to watershed P discharges/dynamics in the Lake Erie (West Lafayette, IN and Columbus, OH) watersheds. The focus will be on smaller watersheds where USDA-ARS or its partners have conducted, or are carrying out, research related to legacy P.
The project will take a two phased approach, informed by modeling but building off of empirical work that we initiate in phase 1, which will support well-documented watershed modeling in phase 2. This agreement covers work for Phase 1. Phase 1 – Characterize legacy P sources in research watersheds, with locally derived, and common, methods. This will involve sampling soils and sediments, hopefully around areas where there are experiments and monitoring (esp. nested). Some samples will be analyzed at a common lab using appropriate methods. We will also use existing models (SWAT, APEX, AnAgNPS, SPARROW, others) to inform our decisions on metrics so that they may be implemented later. The emphasis will be on P characterization, but sediment budgeting/sourcing will also be included. Phase 1 – Assess long-term (>5 yr) Edge-of-Field and small watershed data to assess contributions of new/recent/incidental vs. old/legacy/chronic sources. Legacy P partners and others (CEAP watershed collaborators) will contribute data. Data will be analyzed per routines associated with the Weighted Regressions on Time, Discharge, and Season model or by other methods. Phase 1 – Advance management recommendations to comprehensively address legacy P and nonlegacy P sources, including to be used as scenarios by watershed modelers.