A zero degree of freedom total phosphorus model: 1. Development for Onondaga Lake, New York

Abstract

A seasonal, two-layer, variable volume, mass balance model for total phosphorus in a stratifying eutrophic lake is developed and tested for a single spring to fall interval. The model recognizes settling, sediment release, and vertical mass transport as key in-lake processes mediating phosphorus dynamics. The application presented is termed a “zero degree of freedom” model, as all inputs are determined independently through field and laboratory studies conducted on a test system. The model is considered validated for the test system because simulation results closely match field observations with no calibration (adjustment of model coefficients). Loading reductions at an adjoining wastewater treatment plant, the lake's major phosphorus source, provided an opportunity for model verification. The model framework has utility for other eutrophic stratifying lakes and the “zero degree of freedom” approach will find application where opportunities for both calibration and verification do not exist. © 1997 Taylor & Francis Group, LLC.