Upper Mississippi River - Reno Bottoms Habitat Rehabilitation H&H Modeling

Angly Ulschmid; Riley Mondloch; Mark Christenson

The Reno Bottoms Habitat Rehabilitation and Enhancement Project (HREP) is located at the top of Pool 9 of the Upper Mississippi River (UMR), between Lock and Dams (LD) 8 and 9. Reno Bottoms is a Special Designated Area within the UMR National Wildlife and Fish Refuge. The area is a mix of marsh wetlands, floodplain forests, side channels, and backwater lakes that provide exceptional habitat and recreational opportunities and resembles what the UMR looked like prior to LD construction.

Water levels within Reno Bottoms are determined primarily by the stage discharge relationship at its downstream confluence with the main channel, the hydraulic gradient within Reno Bottoms is low due to the large conveyance area and is heavily influenced by the decrease in the stage-discharge relationship downstream of LD 8 & 9. This decrease was attributed to bed degradation downstream of the LD and an increase in the backwaters conveyance after inundation, which has resulted in habitat degradation, increased tree mortality and erosion of the islands located in the backwaters.

One-dimensional (HEC-RAS) and two-dimensional (ADH) modeling was done to simulate the effects of the proposed features. The ADH model was utilized to estimate velocity and shear stress to inform stabilization measures, design a hydraulic control structure to limit water movement through a fish overwintering habitat feature, and assess the potential for erosion driven by boat wakes. AdH offers several unique advantages over other models, which makes it an ideal tool for this complex project. This presentation covers the final restoration design and how it was informed by hydrologic and hydraulic assessments.

Predicting Ecological Uplift in Urban Stream Restorations Using Data-Driven Watershed Modeling

Wuhib Bayou; Zhuping Sheng

Ecological uplift remains difficult to achieve in stream restoration projects, particularly in urban and urbanizing watersheds where cumulative watershed-scale stressors often overwhelm localized channel interventions. This study presents a data-driven watershed modeling framework to predict ecological uplift potential using nonlinear stressor–response relationships derived from long-term biological monitoring data, with ecological condition represented by the Benthic Index of Biotic Integrity (BIBI). Machine-learning models were trained using watershed-scale predictors encompassing land use, habitat condition, and water-quality stressors to identify dominant controls, interaction effects, and threshold responses influencing biological outcomes. Results indicate that watershed-scale factors—especially impervious cover, riparian condition, and conductivity-related stressors—exert stronger control on ecological outcomes than individual in-stream restoration measures alone, limiting uplift under channel-focused interventions.

Designing Resilient Urban Rivers: Integrating Flood Control, Ecology, and Access

Ben Murphy; Greg Dorolek; Brian Stephens-Hotopp

Cities across the country are rethinking their relationship to urban rivers, moving beyond hardened channels and single-purpose flood control toward integrated, living systems that restore ecological function while supporting recreation, development, and climate resilience. Denver’s River Mile—currently the largest and most complex river restoration and redevelopment effort in the city’s history—illustrates both the opportunities and the challenges of this next generation of watershed-based design.

Led by Calibre Engineering in partnership with the Mile High Flood District, The River Mile transforms a heavily modified reach of the South Platte River into a connected riparian corridor that lowers flood risk, improves water quality, and expands public access and recreation opportunities.

The project is the first riverine system in the nation to earn WEDG (Waterfront Edge Design Guidelines) verification, reflecting its holistic approach to habitat restoration, stormwater management, and community interface. Key strategies include adaptive hydraulic modeling to reduce base flood elevations and remove more than 150 acres from FEMA flood zones; re-meandering and naturalization of channel geometry; integrated wetland and riparian plant communities; and a park and trail network that reconnects neighborhoods to the river.

This session will share lessons learned from planning through implementation, including permitting complexities, stakeholder coordination, balancing restoration goals with adjacent development pressures, and sequencing improvements to maintain river function during construction. Attendees will gain insight into how multidisciplinary, WEDG-based design approaches can create resilient, ecologically functional urban rivers that advance watershed health, long-term community value, and adaptive riverfront infrastructure.