QUAL2K is a Microsoft Windows based application for river and stream water quality modeling. QUAL2K is an updated version of QUAL2E with improvements in model segmentation, forms of carbonaceous BOD evaluated, particulate organic matter simulation, anoxia and denitrification modeling, sediment-water dissolved oxygen and nutrient fluxes, explicit simulation of attached bottom algae, light extinction calculation, enhanced… Read More →

OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage. The… Read More →

OTIS is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. OTIS is often used with data from field-scale tracer experiments to quantify the hydro-logic parameters affecting solute transport. Additional applications include analyses of non-conservative solutes that are subject to sorption processes and/or first-order decay. The governing equation underlying the model… Read More →

LOAD ESTimator (LOADEST) is a FORTRAN program for estimating constituent loads in streams and rivers. Given a time series of stream-flow, additional data variables, and constituent concentration, LOADEST assists the user in developing a regression model for the estimation of constituent load (calibration). Explanatory variables within the regression model include various functions of stream-flow, decimal time, and additional user-specified data… Read More →