USGS Raleigh Stream Bank Erosion Study

The City of Raleigh is partnering with the US Geological Survey (USGS), in coordination with a companion study conducted by NC State University, to complete the Comprehensive Assessment of Streambank Erosion Hotspots in Raleigh, NC project.

This project aims to predict streambank erosion potential using remotely detected datasets. Results will provide the City of Raleigh with a city-wide dataset of streambank erosion hotspots that can be used to identify areas with severe erosion problems, as well as areas with stable streambanks. This information will allow the City to efficiently deploy staff for field investigations and prioritize need and opportunities for stream restoration and stabilization projects. This study will also inform future watershed assessment strategies and help support the creation of a framework for the City's developing Stream and Riparian Program.

Project Details

Type:: Stormwater
Budget:: $394,100
Project Lead:: Stormwater Management
Contractors:: Partnered with USGS

Schedule

DATE	ACTIVITY
2021-2022	GIS Analysis
Fall 2021-Spring 2022	Field Analysis
Fall 2022-Summer 2023	Statistical Analysis
Early 2023-Early 2024	Reporting

The Problem

The City of Raleigh recognizes the prevalence of streambank erosion within the City’s planning jurisdiction. However, current approaches used to locate eroding streambanks, such as stream walks or citizen complaints, are inefficient and inconsistent. Because streambank erosion is highly variable in space and time, it is difficult to scale the magnitude and rate of streambank erosion from individual point-scale measurements to an entire stream network. New tools are needed to remotely identify streambank erosion hotspots throughout the City’s stream network. Multi-temporal high resolution lidar data provide opportunities to track topographic changes, such as erosion and deposition, over time. Models relating field conditions to lidar-derived topographic data allow for the scaling of site-specific measurements of streambank erosion to the larger stream network (Hopkins et al. 2018).

A comprehensive assessment of streambank erosion hotspots throughout the City’s stream network will support the City’s efforts to prioritize future stream mitigation projects, important for ensuring that resources will be used to maximize benefits to stream health, protection of property, and human well-being.

Raleigh Erosion Study Area Map (USGS)

Project Objectives

Generate raster datasets that describe elevation, streambank characteristics, and changes to elevation and streambank characteristics using remotely detected lidar data.
Assess streambank erosion potential in select stream reaches throughout the City of Raleigh using rapid field methods.
Predict streambank erosion potential throughout the Area of Interest (or extent of 2022 lidar collection) using statistical models that relate lidar-derived datasets (Objective 1) to field-based streambank erosion ratings (Objective 2).