B08_ATTACHMENT_1_SOW.pdf

1.0 INTRODUCTION AND BACKGROUND

The U.S. Geological Survey, Water Mission Area, Observing Systems Division, Hydrologic

Remote Sensing Branch (HRSB) needs to procure a mobile, hand-carried, rapidly deployable, transient electromagnetic (TEM) system optimized for high data acquisition rates of several kilometers of profiles per day. New geophysical techniques are needed to help characterize the hydrogeologic properties controlling field-scale groundwater flow and transport in diverse geologic environments. Hydrogeophysical characterization of unconsolidated and fractured-rock aquifers, salt-water intrusion, contaminant mapping, and hydrologic processes are active research and investigation topics pursued at USGS Water Mission Area (WMA) and Water

Science Centers (WSC). Geophysical imaging methods with a small footprint and capable of rapid field setup and data collection are needed to efficiently assess and monitor aquifer systems. A small footprint transient electromagnetic profiling system (sTEM-Profiler) would have direct application to a wide range of groundwater, geotechnical and geohazard investigations associated with USGS WMA and WSC studies that require quantitative aquifer characterization, assessment of saturation, and estimation of water quality, for the development and calibration of groundwater flow and solute transport models and evaluation of hydrologic processes. This equipment fits a unique niche and provides data for a range of applications that we are not currently able to field with our existing equipment. The new TEM system would be used as part of WMA-OSD-HRSB and USGS Office of International Program collaborative research with the Environmental Protection Agency into the use of geophysical methods for subsurface characterization and monitoring and would be available for use by

USGS WSCs for program development and groundwater studies.

2.0 SCOPE

This SOW is for a mobile, hand-carried, rapidly deployable transient electromagnetic system with rigid carry-frame, and integrated transmitter and receiver electronics. The system must allow for wireless connectivity between the control unit and the transmit and receive electronics and to send data to the control unit. However, the system must not require access to the Internet to control the data collection or send data to the control unit. Additionally, the equipment must be able to perform real-time inversions, which would allow for field assessments of the data collections and coverage allowing the users to modify survey plans in real-time. The TEM system must use a fixed offset-configuration transmitter and receiver loop with handles for carrying in the loops in the field and physical dimensions not exceeding 3-meters length by 3-meters width and a 10-meter separation between the loops. Additionally, the transmitter loop must be comprised of at least 2-turns, for increased power and depth of investigation. The system must be sufficient to transmit peak output of 10-Amp current waveform to allow for depths of investigation to reach 100- to 125-meters. The mobile, hand-carried system must utilize removable/replaceable light-weight batteries to support long field days. Additionally, transmitter and receiver electronics must not be required to share battery power. The system must be contained within two shipping cases to facilitate portability in shipping and transport to and from field sites. Total system weight must not exceed 20-kilograms/45 pounds, facilitating a two person carry.

3.0 APPLICABLE DOCUMENTS

Please see technical requirements section.

4.0 TECHNICAL REQUIREMENTS

Transmitter and receiver rigid carry frames allow personnel to place transmitter and receiver loops on the ground and maintain a safe operating distance from the transmitted electromagnetic field and during measurement times.

Realtime inversion of data.

Low-moment transmitter turn-off time should be 4 microseconds, or faster. These turn-off times would allow for data representative of shallow depths (<10 meters).

High-moment transmitter turn-off time should be 8 microseconds, or faster.

Transmitter loop size – 3 meters x 3 meters. Transmitter area of at least 9 square meters.

Receiver loop size – 3 meters x 3 meters with at least 3-turns. Receiver area of at least 27 square meters.

Transmitter-Receiver loop separation should be 10 meters.

Transmitter-Receiver loops contained in rigid carrier with carry handles to support rapid field deployment, measurement, and profiling.

Depth of investigation – 100 to 130 meters.

Single sounding measurement time – 15 to 30 seconds.

Total system weight (including Tx/Rx loops, Tx/Rx electronics, and batteries) – Less than24-kilograms.

System allows for rapid set up and break down for easy mobilization, deployment, shipping, and storage.

5.0 DELIVERABLES

• A mobile, hand-carried, rapidly deployable, transient electromagnetic (TEM) system designed for data collection rates of several kilometers of profiles per day.

• Shipping cases for transmitter/receiver electronics and for the rigid transmitter/receiver loops.

• Power included with lightweight rechargeable batteries.

Delivery Address: U.S. Geological Survey, 11 Sherman Place, Unit-5015, Storrs-Mansfield, CT.

06269