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.

Upper Mississippi River-Pool 9 Reno Bottoms Habitat Rehabilitation and Enhancement Project

Angly Ulschmid; Riley Mondloch; Mark Christenson

The Pool 9 Reno Bottoms Habitat Rehabilitation and Enhancement Project (HREP) is located at the top of Pool 9 of the Upper Mississippi River (UMR), the entire project area is a Special Designated Area within the Upper Mississippi River National Wildlife and Fish Refuge. The mixed ecosystem resembles what the Mississippi River looked like prior to Lock and Dam (LD) construction; the mix of marsh wetlands, floodplain forests, side channels, backwater lakes and flowing water areas provide vital habitat to a great number of terrestrial and aquatic species. The area is also a stop on the Mississippi River migratory flyway which is used by 40% of North America’s waterfowl and shorebirds, eagles and neotropical birds. The purpose of the project is the rehabilitation and enhancement of topographic diversity and establishment of forest cover over approximately 60 acres of islands. Construction of the LD8 and LD9 isolated Upper Reno Bottoms from the Mississippi river; the features are designed to address the degradation of habitat quality resulting from altered hydrologic connectivity due to impoundment, island loss, low diversity in riverbed depth and configuration, and unbalanced sediment transport processes. Increased flood duration and inundation of floodplain forest areas have increased vegetation mortality. Proposed features include elevation of existing islands with fine-grained material obtained from dredging of overwintering habitat features, a hydraulic partial closure structure and forest management plan. One-dimensional (HEC-RAS) and two-dimensional (ADH) models were developed to simulate the effects of embankment modifications and assess the impact of project features in achieving project objectives.

Reproducible Hydrologic Model Building for Recharge Assessment Across Nevada’s Hydrographic Basins

John Volk; Chris Garner; Philip Gardner; Justin Huntington; Kip Allander; Murphy Gardner; Sayantan Majumdar

Quantifying groundwater recharge in the Great Basin is challenging due to complex hydrogeology, strong elevation-driven gradients, and sparse observations, yet increasing demand for defensible water budgets across Nevada’s hydrographic basins requires spatially and temporally distributed recharge estimates. We present the Nevada Water Initiative (NWI) Recharge Modeling Toolkit, a Python framework that automates generation of Precipitation-Runoff Modeling System (PRMS) models, which are distributed and physically-based hydrologic models, for Nevada’s hydrographic basins. The workflow draws on the NWI's “Data Bin,” that includes standard layers for the Great Basin of elevation, STATSGO soils, and LANDFIRE vegetation. The toolkit also retrieves PRISM climate forcings. It performs DEM conditioning, watershed discretization, stream network and cascade delineation, and parameter estimation to produce all inputs for PRMS models. Built-in diagnostic tools and software design enable transparent and reproducible iteration on model building choices. The toolkit requires little coding experience for standard model building workflows via a command line interface and a simple configuration file; however, it also includes an object-oriented Python interface for extending components and performing custom analyses. In addition to automated model builds, the toolkit includes utilities for evaluating PRMS-simulated recharge and summarizing water-budget components for comparison across basins, periods, and alternative configurations. Select results are shown for to NWI demonstration basins: Railroad Valley, a closed hydrographic system, and Pine Valley.

Integrated Hydrological Modeling of an Urbanized Mountainous Karstic Terrain

Yaakov Anker; Vladimir Mirlas; Alexander Gimburg; Michael Zilberbrand

Urbanized karstic watersheds present unique hydrological challenges due to the complex interaction between anthropogenic modifications and inherent karst features, including subsurface conduits, sinkholes, and rapid inhomogeneous infiltration pathways. Traditional watershed modeling approaches often fail to adequately capture these complexities, necessitating innovative data acquisition methods. Aerial and satellite remote sensing technologies have emerged as powerful tools for characterizing and monitoring these dynamic systems. Over the last two decades, Israel's central mountain rim has undergone rapid human development, marked by the establishment of several new towns, the expansion of existing cities, and the alteration of natural areas mainly for agricultural use and road construction. To evaluate the rapid change to natural watersheds across the region, integration of remotely sensed data with Geographic Information Systems (GIS) and hydrological models was applied for flood prevention assessment in one model city and groundwater recharge estimation was done for several major watersheds, including a comparison between natural and urbanized watersheds. Time-series analysis of satellite imagery enabled quantification of land use change impacts on watershed hydrology and a MODFLOW model enabled identifying changes in surface-subsurface connectivity patterns. The urban area hydrological modeling involved a modified HEC-HMS model that utilized the ModClark Transform and SCS Curve Number methods platform for a nominal urban watershed sub-basin analysis procedure, which enabled detailed urban runoff modeling. This integrated karstic terrain modelling procedure for predicting runoff volume and discharge can be used in water-sensitive design to maintain groundwater recharge and mitigate the negative impacts of runoff intensification.