Time-domain electromagnetic soundings collected in Dawson County, Nebraska, 2007-09

Payne, Jason D.; Teeple, Andrew P.

doi:10.3133/ds581

Cited by 3 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Data from each sounding were used to calculate apparent resistivity to depths of about 375-1,100 feet below land surface (Como and others, 2020). Generally, the largest possible loop size was used at any location to increase the likelihood of obtaining the deepest aquifer measurements (Payne and Teeple, 2011). A larger transmitter loop size increases the depth of measurement and increases resistance of the loop wire, which decreases the current.…”

Section: Time Domain Electromagnetic Soundingsmentioning

confidence: 99%

Use of time domain electromagnetic soundings and borehole electromagnetic induction logs to delineate the freshwater/saltwater interface on southwestern Long Island, New York, 2015–17

Stumm¹,

Como²,

Zuck³

2020

Open-File Report

View full text Add to dashboard Cite

The U.S. Geological Survey, in cooperation with the New York State Department of Environmental Conservation, used surface and borehole geophysical methods to delineate the freshwater/saltwater interface in coastal plain aquifers along the southwestern part of Long Island, New York. Over pumping of groundwater in the early 20th century combined with freshwater/saltwater interfaces at the coastline created saltwater intrusion in the upper glacial, Jameco, Magothy, and Lloyd aquifers. This study documents, for the first time, extensive saltwater intrusion of the Lloyd aquifer along the southwestern coast of Long Island, N.Y. Several public-supply wells in the southern parts of Nassau, Queens, and Kings Counties have been adversely affected by saltwater intrusion causing supply wells to be shutdown and abandoned. Due to the ongoing groundwater pumping in southern Nassau County, the freshwater/saltwater interface requires delineation and monitoring for any inland movement. In 2015-17, the U.S. Geological Survey collected time domain electromagnetic soundings at 12 locations and borehole electromagnetic induction conductivity logs at 9 wells within the study area to delineate several saltwater intrusion wedges. The upper glacial, Jameco, and Magothy aquifers were grouped into one aquifer complex within the study area to simplify interpretations. The coastal plain sediments increase in thickness from west to east and north to south because of their regional dip toward the southeast. Three separate wedges, shallow, intermediate, and deep, of saltwater intrusion were delineated in the upper glacial, Jameco, and Magothy aquifer complex. In addition, analysis of geophysical logs collected in an open borehole of a test well in southern Queens County in 1989 revealed the Lloyd aquifer was nearly completely intruded by saltwater with an estimated chloride concentration of 15,000 milligrams per liter. The geophysical logs from this well provides, for the first time, definitive proof of saltwater intrusion of the Lloyd aquifer on Long Island's south shore, suggesting the freshwater/saltwater interface was at the coastline and not miles offshore as theorized by previous studies.

show abstract

Section: Time Domain Electromagnetic Soundingsmentioning

confidence: 99%

Use of time domain electromagnetic soundings and borehole electromagnetic induction logs to delineate the freshwater/saltwater interface on southwestern Long Island, New York, 2015–17

Stumm¹,

Como²,

Zuck³

2020

Open-File Report

View full text Add to dashboard Cite

show abstract

“…The field data used for demonstration of the joint inversion methodologies originate from the Platte River Valley, Nebraska [ Irons et al ., ; Payne and Teeple , ]. The data set comprises TEM, MRS, and aquifer test measurements collected at a location named site 58 northwest of the town of Lexington [ Irons et al ., ].…”

Section: Field Applicationmentioning

confidence: 99%

“…TEM data were collected by the USGS in 2007/2008 using both the Protem 47 and Protem 57 equipment [ Payne and Teeple , ]. The data used in this study were collected using a 40 m square loop with three different moments for both the Protem 47 and the Protem 57 transmitters.…”

Section: Field Applicationmentioning

confidence: 99%

See 1 more Smart Citation

Joint inversion of aquifer test, MRS, and TEM data

et al. 2014

View full text Add to dashboard Cite

This paper presents two methods for joint inversion of aquifer test data, magnetic resonance sounding (MRS) data, and transient electromagnetic data acquired from a multilayer hydrogeological system. The link between the MRS model and the groundwater model is created by tying hydraulic conductivities (k) derived from MRS parameters to those of the groundwater model. Method 1 applies k estimated from MRS directly in the groundwater model, during the inversion. Method 2 on the other hand uses the petrophysical relation as a regularization constraint that only enforces k estimated for the groundwater model to be equal to MRS derived k to the extent that data can be fitted. Both methodologies can jointly calibrate parameters pertaining to the individual models as well as a parameter pertaining to the petrophysical relation. This allows the petrophysical relation to adapt to the local conditions during the inversion. The methods are tested using a synthetic data set as well as a field data set. In combination, the two case studies show that the joint methods can constrain the inversion to achieve estimates of k, decay times, and water contents for a leaky confined aquifer system. We show that the geophysical data can assist in determining otherwise insensitive k, and vice versa. Based on our experiments and results, we mainly advocate the future application of method 2 since this seems to produce the most reliable results, has a faster inversion runtime, and is applicable also for linking k of 3-D groundwater flow models to multiple MRS soundings.

show abstract

Hydrogeologic framework and extent of saltwater intrusion in Kings, Queens, and Nassau Counties, Long Island, New York

Stumm,

Finkelstein,

Williams

et al. 2024

Scientific Investigations Report

View full text Add to dashboard Cite

Time-domain electromagnetic soundings collected in Dawson County, Nebraska, 2007-09

Cited by 3 publications

References 4 publications

Use of time domain electromagnetic soundings and borehole electromagnetic induction logs to delineate the freshwater/saltwater interface on southwestern Long Island, New York, 2015–17

Use of time domain electromagnetic soundings and borehole electromagnetic induction logs to delineate the freshwater/saltwater interface on southwestern Long Island, New York, 2015–17

Joint inversion of aquifer test, MRS, and TEM data

Hydrogeologic framework and extent of saltwater intrusion in Kings, Queens, and Nassau Counties, Long Island, New York

Contact Info

Product

Resources

About