This paper presents SWAT-MODFLOW-RT3D, a model that couples the semi-distributed watershed model SWAT (Soil and Water Assessment Tool) with the groundwater flow model MODFLOW and the groundwater solute reactive transport model RT3D to simulate nitrate (NO₃) fate and transport in a watershed system. The model is based on a recently developed SWAT-MODFLOW model, with RT3D now called as a subroutine within the MODFLOW code to provide a single, stand-alone model code. RT3D uses NO₃ concentration of deep percolation water from SWAT and groundwater heads and flows from MODFLOW to simulate spatially-varying groundwater NO₃ concentration and NO₃ loading to/from streams, with the latter used by SWAT to route NO₃ mass through the network. Model use is demonstrated through an application to the Sprague River Watershed (4100 km²) in Oregon. Other chemical species of interest can be included in the RT3D reaction module in applications of the model to other watersheds.

本文介绍了SWAT-MODFLOW-RT3D模型，该模型将半分布式分水岭模型SWAT（土壤和水评估工具）与地下水流模型MODFLOW和地下水溶质反应性运输模型RT3D耦合在一起，以模拟硝酸盐（NO ₃）的去向和在分水岭系统中运输。该模型基于最近开发的SWAT-MODFLOW模型，RT3D现在被称为MODFLOW代码中的子例程，以提供单个独立的模型代码。RT3D使用NO ₃浓度的深层渗透水从SWAT和地下水头和从MODFLOW流到模拟空间上变化的地下水NO ₃浓度和NO ₃从流加载到/与使用SWAT路由NO后者₃通过网络进行大规模传播。通过在俄勒冈州的斯普拉格河流域（4100 km ²）上的应用演示了模型的使用。在将模型应用于其他流域时，其他感兴趣的化学物种可以包含在RT3D反应模块中。