Modeling nutrient behavior in Wetlands

Abstract

A simple mathematical model os developed which permites dynamic simulation of wetland hydrology and of nutrient-driven interactions between wastewater and the wetland ecosystem. Spatial variations due to surface water flow are described, and material balance calculations carried out for phosphorus, nitrogen, and chloride. A hydrology model, described elsewhere, predicts overland flow. Ecosystem phenomena are represented, using a one-dimensional, spatially distributed compartmental model. Compartments representing active parts of the ecosystem include soil, surface water, interstitial soil water, and various types of live biomass, standing dead and litter. Solutions to the partial differential equations which comprise these spatial models are demostrated using finite-difference methods. Computer simulations are compared with operating data from the Porter Ranch wastewater treatment facility at Houghton Lake, Michigan. They accurately predict solute concentrations in surface water, biomass growth patters, changes in the litter pool, and soil accretion rates.