Geology Reports⌕ Search
Home/Archive/USGS

USGS · 70021295

A mini drivepoint sampler for measuring pore water solute concentrations in the hyporheic zone of sand-bottom streams

John H. Duff·Fred Murphy·Christopher C. Fuller·F. Triska·Judson W. Harvey·Alan P. Jackman
View original source ↗Export metadata ↓

Abstract

A new method for collecting pore-water samples in sand and gravel streambeds is presented. We developed a mini drivepoint solution sampling (MINIPOINT) technique to collect pore-water samples at 2.5-cm vertical resolution. The sampler consisted of six small-diameter stainless steel drivepoints arranged in a 10-cm-diameter circular array. In a simple procedure, the sampler was installed in the streambed to preset drivepoint depths of 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 cm. Sampler performance was evaluated in the Shingobee River, Minnesota, and Pinal Creek, Arizona, by measuring the vertical gradient of chloride concentration in pore water beneath the streambed that was established by the uninterrupted injection to the stream for 3 d. Pore-water samples were withdrawn from all drivepoints simultaneously. In the first evaluation, the vertical chloride gradient was unchanged at withdrawal rates between 0.3 and 4.0 ml min-1 but was disturbed at higher rates. In the second evaluation, up to 70 ml of pore water was withdrawn from each drivepoint at a withdrawal rate of 2.5 ml min-1 without disturbing the vertical chloride gradient. Background concentrations of other solutes were also determined with MINIPOINT sampling. Steep vertical gradients were present for biologically reactive solutes such as DO, NH4/+, NO3/-, and dissolved organic C in the top 20 cm of the streambed. These detailed solute profiles in the hyporheic zone could not have been determined without a method for close interval vertical sampling that does not disturb natural hydrologic mixing between stream water and groundwater.

Explore related subjects

Limnology and OceanographyArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

John H. Duff, Fred Murphy, Christopher C. Fuller, F. Triska, Judson W. Harvey, Alan P. Jackman. 1998. A mini drivepoint sampler for measuring pore water solute concentrations in the hyporheic zone of sand-bottom streams. https://pubs.usgs.gov/publication/70021295

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Increasing artificial light at night enhances salmonid predator foraging efficiency in an urbanized lake

Artificial light at night (ALAN) poses a threat to ecosystems globally. It includes both direct and indirect light, or skyglow, which occurs when ALAN scatters in the atmosphere, extending beyond its original source. We analyzed ALAN trends in Lake Washington, WA, from 2014 to 2023 using Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime light measurements, evaluated the relationship between in situ and satellite measurements, and modeled predator search volumes for a juvenile salmon predator, cutthroat trout ( Oncorhynchus clarki ), as a function of ambient light and turbidity conditions. Open water regions experienced significant increases in ALAN, while nearshore areas primarily showed no or negative trends, revealing the role of skyglow in shaping open water light environments. Using a visual foraging model for cutthroat trout, we found that juvenile salmon at the shallow southern pelagic site experienced light 28 times brighter, resulting in a 168% greater predation vulnerability than those at the northern site. In the Ship Canal, a narrow corridor for outmigrating salmon, predator search volumes were 249% higher than at the southern site. These contrasts in predation vulnerability demonstrate how local conditions influence predator–prey dynamics and provide critical insight for targeting mitigation of both nearshore and distant light sources.

Washington↗
USGS2026

Temperate lake heatwaves accelerate non-linearly as timing synchronizes across a diverse landscape

Temperate lakes are experiencing intensifying heatwaves, or prolonged periods of anomalously warm water, with potentially severe ecological consequences. Previous studies have predominantly used linear trend analyses to understand heatwave dynamics, potentially masking temporal acceleration patterns and shifts in variance. Here, we analyzed long-term, nonlinear trends in heatwave frequency, intensity, and timing across 4391 New York lakes using simulated daily surface water temperatures from an Entity-Aware Long Short-Term Memory deep learning model (validated root mean square error = 1.82°C; 1980–2020). We applied generalized additive mixed models to quantify complex temporal patterns while accounting for lake-specific effects and environmental characteristics (lake surface area, elevation, and latitude). All heatwave metrics demonstrated nonlinear and dynamic temporal trends. Heatwave frequency showed early increases in the number of events (0.05–1.32 events during the 1980s) followed by accelerated growth after 2000; other metrics exhibited more complex decadal patterns. Temporal variance increased significantly for both heatwave frequency ( τ = 0.73, p < 0.001) and intensity ( τ = 0.33, p = 0.003). Lake characteristics drove some heatwave dynamics; smaller lakes experienced higher intensities and complex elevation-latitude interactions varying by heatwave metric. Spatial patterns revealed increasing heterogeneity for heatwave intensity and frequency while heatwave timing homogenized to earlier dates across the landscape. Our findings reveal nonlinear heatwave dynamics with increasing variability, which may reduce predictability and intensify ecological vulnerabilities beyond current projections.

New York↗
USGS2025

Unique thermal mixing patterns in Lake Ontario revealed by novel year-round observations of thermal stratification

Year-round records of thermal stratification in the Great Lakes are rare, and there are few observations of thermal stratification during winter. In this paper, we analyze temperature data from 13 temperature logger chains and from over 130 benthic acoustic receivers that were deployed across Lake Ontario for 2 yr. The timing and duration of the fall overturn correlate with the local average water depth, and shallow sites (< 50 m depth) overturn up to a month before deep sites (> 100 m depths). Likewise, in spring, the shallow sites warm faster. Lake Ontario has partial ice cover, so wind-driven mixing stirs the water column throughout winter, and inverse thermal stratification is largely absent. The depth-averaged winter water temperatures vary between 0°C and 4°C, with the coldest temperatures (near 0.1°C) found in the shallow Kingston basin and warmest temperatures (near 4°C) at sites near the 244 m deep Rochester Basin. Lake Ontario appears to be a warm monomictic lake, rather than having a dimictic mixing pattern as previously described—there is no sustained ice cover or inverse stratification that inhibits vertical mixing in winter. Winter is a poorly understood season for many aquatic processes, including fish bioenergetics, fish distribution, biochemical processes, invertebrate distribution, and production. Moreover, the lack of knowledge of winter has hampered the use of correct initial conditions for running large lake hydrodynamic models.

Lake Ontario↗