NWDTW 2026

This session will highlight some general best practices when flagging, surveying, and computing indirect measurements of peak discharge, as well as identifying some common (and uncommon) mistakes.

Hurricane Helene severely impacted the Asheville Field Area. This presentation looks at impacts from the storm as well as recovery efforts that were undertaken by Asheville Field Office staff as well as assistance from many outside sources. This (hopefully) once in a lifetime storm event led to significant damage and loss of data. Significant effort was put into restoring the network, assigning peak gage heights, and conducting indirect measurements to compute discharge data through the event.

Submersible pressure transducers such as Onset HOBO and Van Essen Diver data loggers can provide valuable stage data when compensated with barometric pressure readings. However, when submersible transducers are deployed in the air, they often prove unreliable as verification for stage records within set uncertainty limits. This unreliability comes from overlapping uncertainties of air pressure readings made by both the absolute and barometric pressure sensors. This talk proposes implementing a new computational method and tool during the compensation process involving the average misalignment between air readings made by both pressure sensors and adjusting all readings within a file by that misalignment. Preliminary results have been promising with most of the affected data aligning closer to verification stage records. This method will enable air-deployment of submersible pressure transducers to be more reliable as a method for peak-stage verification as well as increase the accuracy of air-deployed submersible pressure transducers without secondary data sources, such as tidal records and temporary gage deployments. To streamline the processing of data collected by submersible pressure transducers, we have developed a shiny app that implements this proposed new method automatically when processing air deployments in addition to allowing the processing of submersible pressure transducers via existing methods. This application is intended to produce more accurate data records by using a consistent compensation method between different sensor models while reducing the workload of the user processing the data.

Since 2021, the USGS Real-time Flood Impact Map has evolved through the Next Generation Water Observing System (NGWOS) into an increasingly operational capability that delivers actionable flood impact intelligence.

This hands-on workshop will train participants to enter and document flood impacts within the system. Attendees are encouraged to bring their own flood impact scenarios; alternatively, examples may be selected from National Weather Service flood impact statements. These scenarios will be used for guided, step-by-step instruction on data entry, standards, and quality assurance.

The session will include: (1) an overview of the Real-time Flood Impact Map, (2) criteria for defining and selecting flood impacts, (3) hands-on data entry exercises, and (4) best practices for ensuring consistency and accuracy. The map currently includes more than 6,000 documented flood impacts nationwide and continues to expand in operational use.

Participants will leave prepared to independently contribute high-quality flood impact data and support broader adoption across cooperators and stakeholders.

After the devastation of the 1997 flood, there was agreement in the Fargo-Moorhead community that something needed to be done to prevent a repeat of the catastrophic damages. Planning began for what would become the FM Area Diversion. The process has included studies, permits, Congressional action and hard work from many key entities, including the USGS. Now, the community is on track to have permanent, reliable flood protection by 2027. This presentation will outline the project and USGS's involvement leading up to, during, and post project development.

As site loads increase and resources stay tight, many technicians are being asked to manage more than ever before.

This session looks at how modern gaging technology—cameras, remote communications, enhanced power systems, and smarter backend tools—can help ease that burden by reducing unnecessary trips and highlighting what actually needs attention.

Cableways are essential facilities for obtaining streamflow measurements and water quality samples at many USGS streamgages. This presentation will give an overview of the primary components of cableways and discuss best practices for cableway maintenance and safe operation.

As of Jan 5, 2026, 1,185 of the 9,004 USGS streamgages were ice-affected - approximately 13.2% of our assets that lack the capacity to deliver real-time discharge. Existing USGS under-ice methods require hours to complete, are cost prohibitive, lack the capacity to deliver continuous discharge time series, and place hydrographers at risk. ICE-Edge computes real-time under ice discharge on the “edge” (think by the riverbank) by integrating a RaspberryPi (RPi) computer, python code, uplooking Acoustic Doppler Velocity Meter (u-ADVM), FirstNet modem, and leveraging the probability concept discharge algorithm.

Annual peak streamflow data from USGS streamgages are a critical dataset engineers and hydrologists use for flood frequency analyses that inform bridge designs, floodplain maps, and other projects in and along rivers. Updated Federal guidelines for flood-frequency analysis (Bulletin 17C) were released in 2019, which allow for better use of information published by the USGS, such as censored (greater than or less than) data, and data sources outside of streamgage records, such as historic peaks. In this workshop, attendees will learn how annual peak-flow data are used, what peak flow qualification codes mean and when to use them, what flood information should be included in station descriptions and manuscripts in SIMS, the proper application of “highest since” notes to annual peaks, proper treatment of peak flows at crest-stage gages, and lots of other flood-related facts. An example streamgage will be analyzed with the PeakFQ software to demonstrate application of USGS data to a real-world flood-frequency problem.

This session will cover a few tools for assessing drought, with examples from the record statewide Texas drought of 2011.

The salt dilution method is a technique for measuring streamflow by injecting a trace pulse of sodium chloride (NaCl) into a stream, allowing it to fully mix, and tracking the downstream dilution through changes in specific conductance. Because salt dilution performs well in turbulent or irregular flow conditions where velocity–area methods often fail, it is a practical option for difficult‑to‑measure sites. This presentation introduces the salt dilution method, including how to identify suitable site conditions, the core field procedures for making salt dilution measurements, and the principles behind salt dilution discharge calculations.

A presentation on the application of salt dilution tracer discrete discharge measurements in under ice conditions. An overview of the method and workflow is discussed. Results of under ice measurements will be reviewed emphasizing the successes, technical challenges, and the lessons learned. Including a further discussion on improving accuracy and repeatability of the method in the future.

Standard streamgaging methods to compute discharge rely on placing equipment and personnel in water and integrating velocities and depths at multiple verticals at a channel cross section (25 to 30 to hundreds of hydroacoustic ensembles). However, a paradigm change has occurred with the advent of non-contact platforms such as fixed‑mount and portable velocity radars and drone‑based cameras. The benefits of coupling these platforms and novel algorithms are clear – enhanced safety and increased efficiency.

USGS peak-flow data is one of the most important datasets used to assess flood risk in the United States. This presentation will discuss tools for visualizing USGS peak-flow data and indirect discharge measurements to improve accessibility of USGS flood data. These tools can be used to easily find what USGS peak-flow data are available in an area to inform operations during and after floods events and identify data for use in flood frequency studies.

AreaComp3 was primarily developed to assist with development of Stage-Area ratings for index velocity sites. The program has several other improvements that can assist with the computation of Indirect measurements, specifically Contracted Opening and Critical Depth measurements. This brief presentation will discuss the use of the AreaComp3 tool with X,Y,Z data, and how you can use that output to assist with the computation of Indirect Measurements. This presentation is geared towards users that collect cross section data post flood and need to compute hydrologic properties with that data. It is also oriented towards technicians/hydrologists that work with Indirect Measurements of Discharge and should be familiar with those methods.

Developing reliable upper-end extensions of stage-discharge rating curves is often challenging due to limited high-flow measurements. This presentation outlines a clear hierarchy of preferred approaches—starting with direct flow measurements, followed by indirect methods—and then focuses on practical in-office techniques that can be performed without field work. Methods include estimating peak flows using areal regression (Q vs. drainage area), transferring peak discharges from upstream or downstream gages, and leveraging the StreamStats cross-section cutting tool along with the AreaComp3 software program to generate control and channel geometry. These desk-based strategies allow hydrologists to effectively vet rating descriptor pairs, assess curve shape, and confidently extend ratings to higher stages.