Wetlands play an essential role in overland flow generation by retaining water and providing an environment for the hydrogeochemical functions of a watershed. Few studies have addressed the restoration of past wetlands using wetland-corrected land-use land-cover (LULC) datasets. We evaluated the impacts of wetlands on hydrology and nutrient (nitrogen) loading by comparing Present, Past, and Restored scenarios. A GIS-based data processing procedure was proposed for generating a wetland-corrected proxy LULC raster to mimic the past wetland distribution. This was subsequently incorporated in the Soil and Water Assessment Tool (SWAT) to simulate discharge and nitrogen loading. In addition, two models, with and without using the proxy LULC dataset, were developed to examine the impacts of the proxy LULC on the model performance. The effect of hydroclimatic variations was also assessed by comparing the simulated peak flows and nutrient loads in dry and wet years. The results demonstrated the necessity of using the wetland-corrected proxy LULC data in the water quantity and quality modeling, especially for wet years. Our modeling approach and wetland-oriented LULC correction procedure can be applied to other wetland-dominated watersheds to improve hydrologic and water quality modeling.

湿地通过保留水分并为流域的水文地球化学功能提供环境，在地表径流产生中发挥着重要作用。很少有研究利用湿地校正土地利用土地覆盖（LULC）数据集来解决过去湿地的恢复问题。我们通过比较现在、过去和恢复的情景，评估了湿地对水文和养分（氮）负荷的影响。提出了一种基于 GIS 的数据处理程序，用于生成湿地校正代理 LULC 栅格以模拟过去的湿地分布。随后将其纳入土壤和水评估工具（SWAT）中以模拟排放和氮负荷。此外，还开发了使用和不使用代理 LULC 数据集的两个模型，以检查代理 LULC 对模型性能的影响。还通过比较干旱和潮湿年份的模拟峰值流量和养分负荷来评估水文气候变化的影响。结果证明了在水量和水质建模中使用湿地校正的替代 LULC 数据的必要性，特别是在潮湿年份。我们的建模方法和面向湿地的 LULC 校正程序可应用于其他湿地为主的流域，以改进水文和水质建模。