Re-establishment of wetlands has been promoted by various groups to control future floods in the Red River of the North Basin in North Dakota and Minnesota. Therefore, a study was conducted to simulate runoff and wetland storage in the Hamden and Lonetree watershed sites in the Red River of the North Basin. Data from geographic information system analyses, collected weather data, additional historic weather data, and geomorphology were used in a wetlands hydrologic model to simulate precipitation accumulation, snowmelt, evapotranspiration, soil infiltration, seepage to ground water, surface runoff, and streamflow. Simulated daily mean water volumes for the soil and wetlands in the Hamden and Lonetree watershed sites showed that the soils of the two sites stored as much water as the wetlands throughout most of the simulation period. Total simulated runoff for the Hamden watershed site for the period of record was reduced about 38 percent by increasing the Bisson Lake spillage threshold from 0.009 to 0.60. The additional simulated storage at the larger spillage threshold led to reductions in simulated runoff. Simulated daily mean streamflows for the Hamden watershed site at a Bisson Lake spillage threshold of 0.60 were less than those simulated for the same day at a Bisson Lake spillage threshold of 0.009. However, the peak streamflows simulated for June 2000 and April 2001 at a spillage threshold of 0.60 were about the same as those simulated at a spillage threshold of 0.009. Simulated runoff during flood conditions in April and June 2000 and March and April 2001 was reduced 1 to 6 percent for an increased spillage threshold. Total runoff for the period of record was reduced about 31 percent for the increased spillage threshold. Simulation results indicate total streamflow from a flood event may be reduced by wetland storage, but peak streamflows during a flood event may not be affected substantially.