Lake Huron Phosphorous Efflux | W81EWF 23 SOI 0002

Opportunity Information: Apply for W81EWF 23 SOI 0002

The "Lake Huron Phosphorous Efflux" opportunity is a U.S. Army Corps of Engineers, Engineer Research and Development Center (ERDC) cooperative agreement focused on improving how phosphorus (P) loading is measured and understood as water moves from Lake Huron into the St. Clair River and, ultimately, toward Lake Erie. The core motivation is that several recent studies have converged on the same conclusion: the amount of phosphorus leaving Lake Huron and entering the St. Clair River has likely been underestimated for decades, potentially by a factor of three or more. That underestimation matters because phosphorus is a primary driver of harmful algal blooms and broader nutrient-related water quality problems downstream, especially in Lake Erie, so getting the upstream load right is essential for credible modeling, forecasting, and management decisions.

The grant is rooted in a shift in scientific understanding about how phosphorus behaves in this system. Older approaches treated offshore Lake Huron concentrations as the best representation of the load and discounted river measurements on the assumption that much of the river phosphorus was sediment-bound and therefore not biologically available to algae. More recent work challenges that assumption, showing that at least part of this particulate or sediment-associated phosphorus can be biologically available, meaning it can still contribute to algal growth and ecosystem impacts downstream. The newer, higher load estimates are supported by more frequent direct measurements in Canadian waters and by methods that combine daily turbidity monitoring with statistical relationships (turbidity-P regressions) to estimate phosphorus on days when bottle samples are not collected. A key hypothesis emerging from this newer literature is that the elevated loads are not steady and uniform, but instead are heavily influenced by episodic events, especially wind-driven resuspension of nearshore Lake Huron sediments that can inject pulses of particulate phosphorus into the outflow and river.

A major scientific question the opportunity targets is how phosphorus concentrations and forms change as water travels downstream in the St. Clair River. Prior findings reported substantially higher phosphorus concentrations near the river bottom downstream near Port Lambton than at upstream locations near Point Edward. One explanation proposed in the cited work is that short-lived, high-phosphorus resuspension events may be missed by limited sampling upstream, then become mixed through the water column during transport and are later detected downstream. The opportunity explicitly calls for additional sampling designed to better capture these resuspension-driven pulses so researchers can determine whether episodic events are the missing piece behind the higher downstream loads.

The opportunity also highlights a puzzling discrepancy between two downstream monitoring locations that are geographically close but differ in sampling depth. Loads calculated using phosphorus measurements from Port Lambton have been higher than those based on samples taken across the river at Algonac, even though the sites are only about half a kilometer apart. The notable difference is that Algonac sampling is typically near-surface (roughly 0.5 to 1.0 meters below the surface), while Port Lambton sampling is near-bottom (about 1 meter off the bottom). This creates a strong suspicion that near-bottom samples may be capturing resuspended bed material, bed load influence, or near-bed particulate enrichment that is not well represented by surface grabs. Supporting evidence comes from the observation that conservative dissolved constituents like chloride appear to behave as expected (moving downstream without major transformation), while particulate phosphorus does not. The particulate fraction is much higher at Port Lambton, and related indicators like suspended solids and organic carbon show similar patterns. The grant aims to resolve whether these differences are real features of river transport and vertical structure, or artifacts of sampling approach and depth.

In terms of what the award will actually fund and produce, the project is built around coordinated field sampling and laboratory analysis paired with spatial and statistical interpretation. The U.S. Army Corps of Engineers will collect whole-water samples from the St. Clair River and deliver them to a laboratory for nutrient analysis, with the detailed sampling plan developed collaboratively among ERDC, the grant recipient, and the lab. The recipient is expected to use the laboratory results to conduct spatial analyses that clarify fate and transport of phosphorus, including how concentrations and phosphorus forms vary from upstream to downstream and potentially from surface to near-bottom depending on the sampling design. Another explicit deliverable is linking the discrete sample results to an existing binational sensor network maintained by U.S. and Canadian federal agencies, which suggests the project will not only interpret bottle-sample concentrations but also help translate or calibrate continuous sensor data (for example, using turbidity and other signals to better estimate phosphorus during un-sampled periods and during short-lived resuspension events).

This effort is meant to slot into a larger body of ongoing nutrient work in the St. Clair-Detroit River system, aligning with and extending prior studies cited in the opportunity (including multiple Burniston and Scavia publications and related regional assessments). The broader practical goal is to tighten the science behind phosphorus load estimates leaving Lake Huron, explain why downstream measurements appear higher than upstream ones, determine the role of episodic resuspension and vertical variability, and ultimately improve the accuracy of nutrient inputs used to understand and manage downstream impacts in Lake Erie.

Key administrative details are straightforward. The opportunity is a discretionary Department of Defense program administered by ERDC, offered as a cooperative agreement (indicating substantial federal involvement during the project). The funding opportunity number is W81EWF 23 SOI 0002 under CFDA 12.630, with one expected award and an award ceiling of $170,000. The original posting date was March 9, 2023 with an original closing date of May 9, 2023. Eligibility is listed broadly as "Others," with additional clarification expected in the official eligibility notes for the announcement.

• The Department of Defense, Engineer Research and Development Center in the science and technology and other research and development sector is offering a public funding opportunity titled "Lake Huron Phosphorous Efflux" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 12.630.
• This funding opportunity was created on Mar 09, 2023.
• Applicants must submit their applications by May 09, 2023. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Each selected applicant is eligible to receive up to $170,000.00 in funding.
• The number of recipients for this funding is limited to 1 candidate(s).
• Eligible applicants include: Others (see text field entitled Additional Information on Eligibility for clarification).

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