title: Investigation of river eutrophication as part of a low dissolved oxygen total maximum daily load implementation.
abstract: In the United States, environmentally impaired rivers are subject to regulation under total maximum daily load (TMDL) regulations that specify watershed wide water quality standards. In California, the setting of TMDL standards is accompanied by the development of scientific and management plans directed at achieving specific water quality objectives. The San Joaquin River (SJR) in the Central Valley of California now has a TMDL for dissolved oxygen (DO). Low DO conditions in the SJR are caused in part by excessive phytoplankton growth (eutrophication) in the shallow, upstream portion of the river that create oxygen demand in the deeper estuary. This paper reports on scientific studies that were conducted to develop a mass balance on nutrients and phytoplankton in the SJR. A mass balance model was developed using WARMF, a model specifically designed for use in TMDL management applications. It was demonstrated that phytoplankton biomass accumulates rapidly in a 88 km reach where plankton from small, slow moving tributaries are diluted and combined with fresh nutrient inputs in faster moving water. The SJR-WARMF model was demonstrated to accurately predict phytoplankton growth in the SJR. Model results suggest that modest reductions in nutrients alone will not limit algal biomass accumulation, but that combined strategies of nutrient reduction and algal control in tributaries may have benefit. The SJR-WARMF model provides stakeholders a practical, scientific tool for setting remediation priorities on a watershed scale.
authors.affiliation: Environmental Engineering Research Program, University of the Pacific, School of Engineering & Computer Sciences, Sears Hall, 3601 Pacific Ave, Stockton, CA 95211, USA. wstringfellow@lbl.gov
authors.forename: William
authors.initials: W
authors.lastname: Stringfellow
authors.forename: Joel
authors.initials: J
authors.lastname: Herr
authors.forename: Gary
authors.initials: G
authors.lastname: Litton
authors.forename: Mark
authors.initials: M
authors.lastname: Brunell
authors.forename: Sharon
authors.initials: S
authors.lastname: Borglin
authors.forename: Jeremy
authors.initials: J
authors.lastname: Hanlon
authors.forename: Carl
authors.initials: C
authors.lastname: Chen
authors.forename: Justin
authors.initials: J
authors.lastname: Graham
authors.forename: Remie
authors.initials: R
authors.lastname: Burks
authors.forename: Randy
authors.initials: R
authors.lastname: Dahlgren
authors.forename: Carol
authors.initials: C
authors.lastname: Kendall
authors.forename: Russ
authors.initials: R
authors.lastname: Brown
authors.forename: Nigel
authors.initials: N
authors.lastname: Quinn
mesh_terms: D000818:Animals; D018533:Biomass; D002140:California; D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism; D000077194:Chlorophyll A; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation; D005068:Eutrophication; D005843:Geography; D008954:Models, Biological; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism; D010839:Phytoplankton / Q000254:growth & development; D045483:Rivers
chemical_list: D002734:Chlorophyll; D010100:Oxygen; D000077194:Chlorophyll A