Drainage network development in low-relief landscapes

Continental glaciation tends to "reset" large areas of a landscape with low-relief hummocky topography characterized by little or no integration into a surface-water drainage network. Over time channels carve into these landscapes and connect previously-noncontributing areas into the drainage network, either by headward erosion of headwater channels and ravines or by scour during seasonal overflow of ephemeral wetlands. In other words, drainage networks could develop from the "bottom up" or the "top down", or some combination of the two. The rates and controls on these processes might be different, and could lead to distinct drainage morphologies.

Role of bed and bank erosion in fluvial sediment and nutrient budgets

Stream bed and bank erosion are thought to represent a significant contribution to sediment and nutrient loads Iowa’s streams, sometimes exacerbating downstream eutrophication and turbidity impairments. The size of these contributions are not well known in time or space, and may depend on many factors including watershed land use, stream channelization history and hydrological regime, soil composition and texture. While upland in-field and edge-of-field practices for soil loss and nutrient reduction have shown promise for reducing sediment and nutrient loads in streams, they have little or no impact on sediment and nutrients derived from within the stream corridors themselves.

Stream restoration science and practice in Iowa

Stream restoration is a growing field in the state of Iowa, and one that is sometimes motivated by different values or concerns than those that motivate restoration in salmon or timber country. Stream restoration in Iowa also faces somewhat different challenges, including diverse private property ownership, historic channelization and hydrological modification. As Iowa develops best practices for stream restoration efforts in the state, the Applied Geomorphology lab is seeking to understand how and when restoration practices can provide the most benefit given our particular geologic settings, management histories, and social/cultural dynamics.

ARCHIVE: Large wood and channel geometry in midwestern alluvial streams

THIS PROJECT IS NO LONGER ACTIVE.

While much of the midwest is prairie and cropland, forest has been historically widespread on steep valley slopes and in riparian areas. When trees are introduced into the channel through bank erosion, storm mortality, or beavers, many physical and biological aspects of streams can be affected. While large wood has been studied extensively in mountainous gravel and cobble-bed streams in the northwestern U.S., little is known about the impacts of large wood in low-gradient midwestern streams with sand and gravel beds and deciduous riparian trees. We are investigating the role of large wood in channel morphology, sediment transport and biotic integrity in wadeable streams of Iowa and neighboring states.

Contacts: Bridget Livers, Pete Moore, Dick Schultz

ARCHIVE: Landscape and water resource evolution in areas of debris-covered ice

THIS PROJECT IS NO LONGER ACTIVE.