Hydrologic Hazards

The Issue: Most of the Lower Duwamish River Valley in Seattle, Washington, is less than 20 feet above sea level; consequently, the river valley is prone to flooding during high tides, extreme rainfall, and high streamflow. In addition, groundwater inundation—localized coastal flooding due to a rise of the groundwater table with global sea-level rise—may compound flooding issues in the area. The...

The Issue: Wildfires can negatively impact reservoirs and water supply. On August 4th, 2021, a lightning strike started the Muckamuck fire in Okanagan County, Washington. The fire burned approximately 13,297 acres (~21 square miles) of forest and shrubland before it was contained. The burn engulfed a large portion of the area which drains into the Conconully Reservoir, a popular location for...

The issue: National interests in water information are important but challenging to incorporate into planning and operation of a monitoring network driven by local information needs. These interests include an understanding of the spatial variability in water availability across the United States, anthro-physical factors including climate and land use that affect water availability, and federal...

The issue: In the summer of 2020, the Pilchuck Dam will be removed, allowing salmon access to the upper third of the Pilchuck River watershed for the first time in over a century. This removal will be associated with a short period increased sediment delivery, as the river re-works material trapped behind the dam. While the volume of impounded sediment is small and major changes in the downstream...

In the immediate aftermath of the SR530 Landslide, the USGS supported first responders and decision-makers as a key member of the collaborative effort to monitor the stability of the landslide deposit and the associated impoundment of the North Fork Stillaguamish River during rescue operations. With the initial disaster response now over, longer-term questions have arisen regarding the stability...

The Issue: Large, in-channel wood that helps to create and maintain healthy aquatic habitat in rivers throughout the Pacific Northwest was removed from many rivers in the past. In 2009, King County put wood back into the river to restore the Raging River watershed. To guide the county's restoration of the Raging River watershed, managers need to know the effect of restoration actions on in-stream...

The Issue: Since 1952 water diverted from the Columbia River has been used to irrigate parts of the Pasco basin in eastern Washington. As a result of the surface-water irrigation, groundwater levels generally have risen in the area. The increases in groundwater fluxes and groundwater in storage have created a need to better understand the flow system before and after the start of irrigation to...

The Issue: Significant flooding occurred throughout western Washington on January 7 and 8, 2009. As part of its Hazard Mitigation effort, the Federal Emergency Management Agency (FEMA) Region X needs documentation on the extent of flooding for verifying Preliminary Digital Flood Insurance Rate Maps (DFIRMs) and corresponding Flood Insurance Studies (FIS) that have been recently completed, or are...

9722-DRE00 - FEMA Technical Support, Pre-Declaration, January 2009 Floods - Completed FY2009 A wide plume of warm moist air streaming in from west of Hawaii caused widespread rainfall throughout western Washington in early January 2009. National Weather Service flood stages were exceeded in many different basins, most of which drain from the west side of the Cascade Range. Flows at four long-term...

Nationally, the USGS monitors and assesses geologic and hydrologic natural hazards. In the Puget Sound Basin, common hazards that also can cause damage include earthquakes and floods. Other hazards in the region that cause less damage or happen less frequently include landslides, debris flows, tsunamis, and volcanic eruptions. Although much is known about these natural hazards, mitigation and...

Honduras is currently (2001) rebuilding its housing and infrastructure that was destroyed by Hurricane Mitch. To plan responsibly and minimize damage during future floods, the Honduran government needs reliable maps of the areas and depth of inundation by the 50-year flood, the design flood chosen for this project. A systematic method for defining areas and depths of inundation is needed that can...

The Puyallup River Basin lies mostly within Pierce County, Washington, and contains 972 square miles of land ranging in elevation from zero at its mouth in Puget Sound to 14,408 feet at the top of Mount Rainier. The cities of Tacoma, Puyallup, Sumner, and Orting are some of the population centers located in the basin. To protect lives and property in the basin, Pierce County needs accurate...