2 Sep 2026

Riparian Model Evaluation in Beargrass Creek, Kentucky

Purpose: With the growing demand for ecological restoration and accompanying use of ecological models to inform decision-making, there is a pressing need for efficient and effective model evaluation procedures in restoration planning. Ecological complexity and diverse modeling frameworks (e.g., quantitative habitat models versus semiquantitative assessments versus qualitative professional judgment) each create challenges for the verification and validation of ecological forecasting tools. This study evaluates the effectiveness of a semiquantitative riparian assessment model, the Simple Model for Urban Riparian Function (SMURF), relative to herbaceous vegetation community data collected from Beargrass Creek in Louisville, Kentucky. Vegetation community metrics were collected at 15 sites, including species richness, diversity, and native versus invasive species composition. These metrics were compared to multiple SMURF outputs to evaluate model accuracy and reliability. Findings indicate that SMURF metrics are minimally predictive of the empirical vegetation metrics examined here (i.e., 5 of 32 models met criteria for statistical significance). However, vegetation-oriented components of the SMURF model more directly aligned with empirical observations, potentially indicating that the aggregation of many metrics in SMURF makes comparisons with empirical data inappropriate. This study demonstrates the challenges in evaluation of broad-scoped, multimetric indices like SMURF relative to empirical metrics for a particular taxonomic group. These findings also provide insight into the potential limits of commonly used semiquantitative methods for ecosystem assessment.

2 Sep 2026

A Web Application for Riparian Models (WARM)

Purpose: Riparian ecological models are widely used to support restoration planning, impact assessment, and mitigation, but many existing tools remain difficult to locate, interpret, and execute. This technical note documents the development of the Web Application for Riparian Models (WARM), a browser-based platform that compiles and executes nine previously developed riparian models in a standardized interface. WARM provides two primary capabilities: a model comparison tool that helps users identify appropriate models based on project characteristics and a suite of calculators that automate model execution with built-in error checking. All source code is maintained in publicly accessible repositories to support version control, transparency, and future expansion. This technical note describes the model selection process, software architecture, and evaluation procedures used to verify numerical accuracy and assess usability. By reducing technical barriers and centralizing access to riparian modeling tools, WARM improves the practicality and long-term shareability of ecological models for US Army Corps of Engineers (USACE) projects and other restoration applications.

2 Sep 2026

Updating Ecological Modeling Within the US Army Corps of Engineers (USACE): Exploring Innovative Approaches and Implementation Strategies

Abstract: The US Army Corps of Engineers (USACE) engages in the planning, de-sign, construction, monitoring, and adaptive management of aquatic eco-system restoration projects. Like many organizations, USACE uses ecological models to inform decisions regarding ecosystem restoration and management. Most ecological modeling to support ecosystem restoration is conducted using habitat and other index models. However, these approaches have changed little in decades, while the field of ecology has seen the rapid growth of new modeling techniques with an array of applications. More advanced ecological models have the potential to align more closely with aquatic ecosystem restoration project objectives, provide more accurate predictions, and improve the communication of restoration benefits. This overview of modern ecological modeling approaches highlights promising ways to increase the use of advanced ecological models to sup-port ecosystem restoration. We describe the characteristics, benefits, and constraints of five ecological modeling families—agent-based models, population models, community models, connectivity/network models, and machine learning methods—and their applicability to ecosystem restoration projects. We also outline important considerations for selecting eco-logical models for a given scenario. Finally, we highlight promising avenues for increasing the use of contemporary modeling approaches, including the value of conducting targeted case studies, in light of project planning constraints.

29 Aug 2025

Developing Conceptual Ecological Models for Hydraulic Analysis

Purpose: Technological advances, coupled with increased availability of spatial and monitoring data for hydraulic analysis, environmental flows analysis, and remote sensing, present opportunities for novel investigations of the structure and function of ecological systems. To leverage these capabilities in ecological analysis, it is necessary to develop a framework that links engineering model capacities with ecological principles. It is well known that riverine ecosystems are complex systems at the intersection of channel form, stream flow volume, and biology. However, because of differences in technical language and analytical philosophy, there are practical challenges associated with cross-walking multidiscipline riverine studies into interdisciplinary efforts that comprehend both engineering and ecological principles. Challenges associated with cross-discipline communication and framing the scope of ecohydraulic analysis are inherent barriers that limit the traction of research crossing disciplinary boundaries.

11 Jul 2025

Lower Mississippi River Resource Assessment: Library of Aquatic Habitat Models

Abstract: Six ecosystem models were developed to evaluate restoration measures for the Lower Mississippi River Resource Assessment that considered connectivity between river and floodplain, substrate quality in riverine habitats, and targeted species of special interest including Paddlefish and wetland fish assemblages. A total of 85 restoration measures in the Hatchie to Loosahatchie reach were identified by the Project Delivery Team that had different modeling requirements. Field data collected by the Engineer Research and Development Center–Environmental Laboratory in the Lower Mississippi River and floodplain identified ecological guilds of fish and aquatic invertebrates representative of different fluvial habitats. Regression and frequency bar chart models developed from this database predicts a biotic response as a function of habitat quality. Six models applicable to either riverine (unidirectional flow) or floodplain (bidirectional flow) environments were used to evaluate measures for enhancing benthic substrates, reestablishing woody debris, and formation of eddies to diversify habitat. Outputs were normalized as a Habitat Suitability Index on a 0–1 scale and a spreadsheet developed to calculate and annualize Habitat Units for selected restoration measures. Models were certified by US Army Corps of Engineers National Ecosystem Restoration Planning Center of Expertise for regional use in the Lower Mississippi River.

4 Jun 2025

Comprehensive Marsh Model Demonstration—Seven Mile Island Innovation Laboratory: Integrating Hydrodynamic, Morphodynamic, and Vegetation Modeling Components Using the Landlab Toolkit

Abstract: Marshes are highly dynamic landscapes that are shaped through feedbacks between hydrodynamic, morphodynamic, and ecological processes. Future marsh resilience is therefore dependent on the interaction between these different drivers rather than any individual piece. Marshes face a variety of threats, both natural and anthropogenic, resulting in a need for restoration actions that increase survivability. Because many of these threats are unprecedented or acting at unprecedented rates, statistical models do not adequately represent future conditions and require process-based models to better capture the complex interactions between both physical and ecological processes. This report demonstrates how to develop a comprehensive marsh model that integrates tidal flow, morphodynamics, and vegetation growth using the Python based Landlab toolkit. The model was applied to a site within the Seven Mile Island Innovation Laboratory complex in coastal New Jersey.

29 May 2024

Comparing Ecological Models for Assessing Rio Grande Silvery Minnow Response to Environmental Flows

Abstract: The proliferation of continuous streamflow monitoring and spatial data suitable for hydraulic modeling is increasing opportunities to use hydraulic habitat analysis to inform ecological models. However, species population and streamflow data exhibit high variability, making it challenging to identify hydrologic and hydraulic metrics that effectively correlate with ecological outcomes. Metric selection presents a challenge for informing environmental flow decisions and adaptive management of water infrastructure. This study applies models to characterize environmental flows with in-creasing model complexity, including the use of hydraulic models to estimate suitable habitat areas at a given flow. The results are compared to field-measured fish outcomes over the same period using functional data analysis. The variance in model correlation with ecological outcomes aids in identifying the most effective environmental flow parameters while also indicating potential pitfalls from increasing model complexity. This analysis demonstrates techniques that synthesize environmental flows with available habitat analysis and validates the approach. The case study is based on the Rio Grande silvery minnow (Hybognathus amarus, minnow), an endangered fish species in the Middle Rio Grande. Analysis focused on different methods to quantify spring runoff coinciding with the inundation of floodplain nursery habitat necessary for the minnow’s larval and juvenile life stages.

28 Feb 2024

Ecological Model to Evaluate Borrow Areas in the Lower Mississippi River

Abstract: An aquatic analysis of constructing borrow areas adjacent to the main line levees in the Lower Mississippi River was conducted as part of an Environmental Impact Statement for upgrading the levee system. A Habitat Suitability Index (HSI) regression model based on field collections was developed to predict fish species richness as a function of the morphometry and water quality of borrow areas. The HSI score was multiplied by acres of borrow areas created during construction to obtain habitat units (HUs) for each alternative indicating a substantial gain of fishery habitat in the floodplain. Environmental features identified by the model to increase fish species richness and overall habitat heterogeneity include the shape of the pit (e.g., bowl-shaped with deep water rather than long rectangular with shallower water), the availability of littoral areas for fish spawning and rearing, using best management practices such as tree screens and bank stabilization to lower turbidity, adding islands, and creating sinuous shorelines. The project results in an overall gain in aquatic habitat by creating permanent or semi-permanent water bodies on the floodplain that our research indicates may be occupied by at least 75 species of fish contributing to the overall biodiversity of the lower Mississippi River.

22 Jan 2024

Considerations for Integrating Ecological and Hydrogeomorphic Models: Developing a Comprehensive Marsh Vegetation Model

PURPOSE: Predictive models for salt marsh management require a systems perspective that recognizes the dynamic interactions between physical and ecological processes. It is critical to link physical process and landscape evolution models to quantify hydro-eco-geomorphic feedbacks in marsh environments. A framework that explicitly defines how to integrate these disparate models is a necessary step towards developing a comprehensive marsh model. This technical note (TN) proposes an approach to integrate existing hydrodynamic and geomorphic models with a mechanistic vegetation model into a coupled framework to better simulate salt marsh evolution.

5 Oct 2023

Review of Riparian Models for Assessing Ecological Impacts and Benefits

BACKGROUND: Riparian zones are key transitional ecosystems between upland and aquatic zones, and these systems are often degraded due to both land use change and stream processes (e.g., deforestation and water impoundments and/or diversions). These important ecosystems require restoration because of the many benefits they provide ranging from providing habitat for diverse species to promoting water quality. Restoration practitioners, regulators, and researchers require riparian assessment methods and models to efficiently guide mitigation and restoration planning. This technical note (TN) compiles a subset of existing riparian tools and evaluates them relative to model objectives, modeling approach, and input variables. Findings are synthesized into a gap analysis of these models to inform future riparian model development and improve riparian assessment.