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NALMS 2026 Workshop: Sediment Phosphorus Inactivation in Lakes and Ponds

  • 3 Nov 2026
  • 8:00 AM - 5:00 PM
  • Delta Hotels Grand Okanagan Resort, Kelowna, British Columbia, Canada
  • 30

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Internal phosphorus (P) loading because of sediment P release is widely recognized as a critical source of P that must be reduced to meet water quality goals and reduce nuisance, and sometimes harmful, algae blooms in lakes and ponds. One of the more common approaches for controlling sediment P release is the application of metal salts to bind the sediment P, minimizing its recycling potential. Some of the more common metal salts include aluminum, lanthanum, iron and calcium which can be applied in many forms using various strategies to accomplish P reduction goals. The successful use of these inactivation agents requires a thorough knowledge of sediment chemistry and P release dynamics, dosing, and application strategies. However, all of these materials share similar data requirements and calculation approaches to develop an effective approach to minimize sediment P release. The purpose of this workshop is to develop an understanding of data requirements, diagnosis and quantifying internal P loading, dosing methods, and application strategies to develop a successful sediment P inactivation project. While the workshop will cover dosing and application strategies for the most commonly used sediment P activation agents, the use of aluminum sulfate will be the focus since it is historically the most widely used approach in the US.

This workshop provides a systematic overview of planning, diagnosis, monitoring, dosing and application technologies for using alum (and other inactivation agents) for P control. Application strategies for deep and shallow lakes include a) water column P stripping, b) P interception, c) maintenance dosing, d) sediment P inactivation and e) P control in ponds. We provide overviews of the history of sediment phosphorus inactivation, long-term efficacy, inactivation chemistry, diagnostic and modeling tools, methods for quantifying internal P load, dosing calculations, application technologies and monitoring requirements. While the use of aluminum is the focus of the workshop, we will also briefly cover other inactivation agents where possible. Numerous case studies will be presented, and participants are invited to present their lake’s concerns. The workshop is interactive and there is ample time for discussion.

Presenters

Shannon Brattebo is an environmental engineer and limnologist. Shannon’s work has focused on lake and reservoir water quality, restoration, and management both in the Pacific Northwest and across the nation. Shannon has been a member of NALMS since 2001, served as NALMS Region 10 Director and is currently the NALMS Treasurer. Joe Bischoff is a limnologist with Barr Engineering, Inc. whose work focuses on phosphorus cycling in deep and shallow lakes, reservoirs and ponds. Joe has completed over 30 successful sediment phosphorus inactivation projects and analyzed sediments from hundreds of lakes. Joe is currently President of the newly formed Minnesota Lake Management Association and the NALMS Region 5 Director. John Holz is a limnologist who leads SOLitude Lake Management’s nutrient remediation efforts, specializing in both small and large-scale alum applications. John is a longtime NALMS member and has served on the NALMS board of directors.

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