Background
Flooding Issues within Yahara River
Dane County is currently undergoing a project that will remove large amounts of sediment from the Yahara River in an attempt to address flooding issues. In 2018, there was widespread flooding in the Yahara River watershed in the Madison area which caused over $154 million in damages. This was an especially worrying flood as it was considered a 1000-year flooding event. Floods of increasingly rare magnitude have been happening with higher frequency and the intensifying of storms can be attributed to global warming. As global warming changes the climate to bring larger storm events, flooding within the Yahara River watershed is happening at higher magnitudes and with increasing frequency. Currently, water flows into the Yahara lakes faster than it is leaving. This contributes to the flooding seen in the lake systems in the previous years. Sediment buildup contributes to the slow water movement of the water through the lakes. This buildup has been increased due to human activity such as urban development and winter sand operations.
Dane County Sediment Removal Project
The goal of the Yahara River Sediment Removal Project is to improve water flow. Two inches of rain currently takes two weeks to travel through the Yahara Lakes system and the goal of the project is for it to take only one week. The overall project will take place in five separate phases. We will be looking at the first phase which is the section between Lake Monona and Waubesa. We chose to model Phase 1 as it was the first phase completed and we want to know the hydraulic effects of the first phase of the project. Phase 1 involves the removal of 40,000 cubic yards of sediment and will be removed by suctioning sediment from the river bottom and into a dewatering basin. The sediment will then be dried and used for other projects.
