Sonoma State University

Evaluation of Proposed Water Quality Credit Generating Locations in the Laguna de Santa Rosa

Laguna de Santa Rosa water quality

Funded by WATERS Collaborative

Abstract

The North Coast Regional Water Quality Control Board determined that absolutely no phosphorus may enter the Laguna de Santa Rosa as a point source pollutant. This is problematic for sewage treatment facilities in Santa Rosa and Windsor that are unable to completely remove phosphorus during the wastewater treatment process. They have no choice but to discharge effluent containing phosphorus into the Laguna de Santa Rosa during high rain events. To offset the negative ecological impact of this phosphorus discharge, a Water Quality Trading Credit system was created. This system was first used in 2019 when Sonoma Water generated Water Quality Trading Credits by removing 11,104 cubic yards (1,388 truckloads) of sediment containing 15,000 pounds of phosphorus from the Laguna 1 region of the Laguna de Santa Rosa. There is now a need to generate additional phosphorus Water Quality Trading Credits. The goal of this study was to test phosphorus levels from three potential new sediment removal sites to determine which site would yield the highest number of Water Quality Trading Credits. Results were compared with phosphorus data collected between 2018 and 2022.

Results

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Evaluation of Proposed Water Quality Credit Generating Locations in the Laguna de Santa Rosa

poster

 

Powerpoint slideshow

 

Guilford Phosphorus Poster April 2026.pdf (32.38 MB)
Cole Carignan, Daniela Ceja, Isaac De La Cruz, Antonio Fernandez, Gabriela Galan Manuel Garcia, Julian Goldberg, Laila Guerra, Star Kirkwood, Chloe Madison Knights, Tim Miller, Cecelia Oberts, Yanin Rivera, Jacob Rosas, Robert St. Jacques

 

Key Terms: water, water quality, phosphorous, Water Quality Trading Credit, Copeland Creek, Laguna de Santa Rosa Watershed

Project Date: Spring 2026
 

Faculty:

  • Jackie Guilford

 

Departments:

  • Geography Environment and Planning

 

Partners:

  • Sonoma Water
  • SSU Center for Environment Inquiry

 

Students:

  • Cole Carignan
  • Daniela Ceja
  • Isaac De La Cruz
  • Antonio Fernandez
  • Gabriela Galan
  • Manuel Garcia
  • Julian Goldberg
  • Laila Guerra
  • Star Kirkwood
  • Chloe Madison Knights
  • Tim Miller
  • Cecelia Oberts
  • Yanin Rivera
  • Jacob Rosas
  • Robert St. Jacques

 

Locations:

  • Sonoma County
  • Copeland Creek
  • Sonoma State University

 

Project Topics:

  • Water
  • Water Quality
  • Phosphorous
  • Laguna de Santa Rosa Watershed
  • Water Quality Trading Credit

 

Funding Sources:

  • WATERS Collaborative
  • Koret Foundation

 

Sonoma State University acknowledges the Coast Miwok, Central and Southern Pomo, and the Wappo as the traditional stewards of our preserved lands. Let it be acknowledged that the Sonoma State University campus is located within the traditional homelands of the Federated Indians of Graton Rancheria. Sonoma State offers deep gratitude to the original stewards of this land and recognizes its immense historical, spiritual, and personal significance to the Native nations and peoples of this region.

Sonoma State University reconoce a los Miwok de la costa (Coast Miwok), los Pomo del centro y del sur (Central and Southern Pomo), y los Wappo como los guardianes tradicionales de nuestros terrenos preservados. Cabe destacar que el campus de Sonoma State University está ubicado dentro de las tierras tradicionales de los Indios Federados de Graton Rancheria (Federated Indians of Graton Rancheria). Sonoma State expresa su profunda gratitud a los guardianes originales de esta tierra y reconoce el inmenso significado histórico, espiritual, y personal a las naciones y pueblos indígenas de esta región.