Reports

The U.S. Geological Survey evaluated the stability of water-sample chemical analysis of nutrient, alkalinity, and acid-neutralizing capacity constituents with respect to the duration between sample collection and laboratory analysis, also known as the sample holding time. A study began in the spring of 2023 to evaluate the sample stability, between 2 and 180 days after sample collection...

The Shoshone-Paiute (Sho-Pai) Tribes of the Duck Valley Reservation, Nevada, manage reservoirs that support commercial and recreational activities, including robust Oncorhynchus mykiss (rainbow trout) fisheries that attract anglers year-round. Reservoirs are common environments for methylation and bioaccumulation of mercury, which is a potent neurotoxin when elevated levels are consumed...

Flood-frequency analysis is based on records of annual maximum instantaneous flows observed at long-term streamgages with 10 years or more of operation. Since the last flood-frequency analysis in Nebraska, an additional 30 years of annual peak-flow data have become available, and new flood-frequency analysis techniques have been developed. Moreover, the Elkhorn River Basin in north...

This study compared the efficacy of a benthic mat alone with carbon dioxide infusion under a mat for killing Dreissena polymorpha (Pallas, 1771) (zebra mussel). Three sites were selected in Loon Lake, Sleeping Bear Dunes National Lakeshore, Benzie County, Michigan, for replication of reference, benthic mat, and carbon dioxide mat treatments. Within a site, three 4-meter (m) x 4-m plots...

Magnetic surveys are an important tool used to augment geologic mapping in distributed volcanic fields. Using magnetic anomalies, it is possible to model the geometry of shallowly buried volcanic features, such as conduits, sills, and lava flows. This subsurface mapping is important for understanding eruption dynamics and emplacement of lava flows, and it sometimes reveals buried...

Introduction In 1921, the U.S. Geological Survey (USGS) established a streamgage on the Colorado River at Lees Ferry, Arizona, to monitor the river’s flow and level as it enters Grand Canyon. The following year, the seven States encompassing the Colorado River Basin (Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming) negotiated the 1922 Colorado River Compact to...

The U.S. Geological Survey monitors a suite of intertidal black abalone (Haliotis cracherodii) sites at San Nicolas Island, California, in cooperation with the U.S. Navy, which owns the island. The nine rocky intertidal sites were established in 1980 to study the potential effect of translocated sea otters on the intertidal black abalone population at the island. The sites were monitored...

The grasslands in the North Central region are managed by a diverse group of Federal, State, and Tribal agencies; nongovernmental organizations; partnerships; and private landowners. This chapter highlights these various grassland management entities, provides background information on their mission and organizational structure, and describes some of their key grassland management...

The Critical Minerals in Ores - Mineral Chemistry (CMiO-MIN) database (Hawkins et al., 2026) is designed to capture ore and ore-related mineral compositional data from critical mineral-bearing deposits across the globe. Samples included within this database must be well-characterised and come from localities that have been sufficiently studied to have a reasonable constraint on their...

No abstract available.

Montana Fish, Wildlife and Parks (MFWP) uses the integrated Patch Occupancy Model (iPOM) to estimate statewide and regional wolf abundance. During the early years of recovery, wolf abundance was tracked using minimum counts. As the population increased, limitations of this method became apparent, motivating development of a model-based approach for estimating abundance. iPOM development...

In 2024, the Alaska Volcano Observatory responded to eruptions, volcanic unrest or suspected unrest, increased seismicity, and other significant activity at 10 volcanic centers in Alaska and the Northern Mariana Islands. Eruptive activity in Alaska consisted of the eruption of a thick lava flow within the summit crater at Great Sitkin Volcano throughout the entire year and a small...