12/14/2017 Advanced Technology Used to Monitor Ground Water in a Restricted Access Area of Fort Riley, Kansas

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USGS Fact Sheet 015-98

March 1998

Advanced Technology Used to Monitor

Ground Water in a Restricted Access Area

of Fort Riley, Kansas

--J.D. Breedlove, P.J. Finnegan, and N.C. Myers

The purpose of this fact sheet is to describe how advanced communication technology is being used

to overcome difficulties in collecting reliable ground-water data in areas with restricted access, such

as at Fort Riley in northeast Kansas.

Table of Contents

Problem

Solution

Equipment

Data Transmission and Storage

Preliminary Data

Problem

Volatile organic compounds (VOCs) were identified in ground water from monitoring wells and in

water from an intermittent spring in the Open Burn/Open Demolition (OB/OD) area at Fort Riley,

Kansas. In 1997, Fort Riley requested that the U.S. Geological Survey (USGS) monitor ground-water

levels and precipitation in an effort to determine the directions of ground-water flow and the hydraulic

response of ground water and streamflow to precipitation. The area contains a complex hydrologic

system where it is difficult to determine ground-water flow direction, if groundwater-bearing zones

are interconnected, and where ground-water discharge points are located. The data collected will be

used to help evaluate the fate and transport of VOCs in the OB/OD area.
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The OB/OD area lies within a "buffer" area on the edge of artillery and mortar ranges at the post. The

OB/OD area is used by Army personnel to destroy unserviceable ordnance. During detonation, some

ordnance may be cast into the surrounding area where it poses a potential explosive hazard to

personnel entering the area. This hazard is mitigated by having qualified ordnance personnel inspect

and clear the OB/OD work areas prior to access by USGS and other personnel.

It is difficult to service traditional hydrologic data-collection instruments in a timely manner at

restricted access areas. Traditional instruments, such as chart recorders or nontransmitting electronic

data loggers, need to be serviced at regular intervals to collect recorded data and to ensure that the

equipment is working properly and the data collected is of the highest quality.

Solution

Hydrologic data-collection platforms (DCPs) equipped with satellite telemetry and cellular-phone

technology (fig. 1) are currently (March 1998) in use at the OB/OD area located at Fort Riley. During

1997, piezometers and monitoring wells were equipped with DCPs to measure and transmit groundwater-level data. Each piezometer was set to a different depth (nested, fig. 2) to allow monitoring of

five or six water-bearing zones. The use of these technologies allow USGS personnel to overcome the

difficulties inherent in collecting data at restricted access areas.

Figure 1. Hydrologic data-collection platform (DCP) using satellite telemetry and

cellular-phone technology allow remote data collection in restricted access areas.

Figure 2. Nested piezometers.

Another benefit of using this advanced technology is the near-real-time availability of data. This

availability allows surface- and ground-water sampling at the OB/OD area to be closely coordinated

with changing hydrologic conditions.

Equipment

Equipment was selected on the basis of compatibility with the monitoring needs and restricted access

conditions. Monitoring and data-transmission challenges included: finding sensors small enough to fit

inside small-diameter piezometer casings; facilitating communication between the sensors and the

data logger; and programming the data logger for satellite communication and cellular-phone

capabilities. The equipment is housed in a 36-inch x 30-inch x 12-inch aluminum shelter (fig. 1).

Precipitation data are collected with a tipping-bucket rain gage near one of the piezometer nests.

Because of the small (0.75-inch) inside diameter of the piezometers, a sensor that was smaller than

0.75 inch was required to measure ground-water levels. The only sensors available that were small

enough to fit in the piezometers were those that send an analog signal. These sensors send a

continuous direct current, the amperage of which varies according to the water pressure at the sensor's

measurement port. The sensors' analog signals are converted to digital signals using a small converter

wired between each sensor and the data logger.

The data logger used to record measurement values from the sensors can communicate with several

analog-to-digital sensors over a single wire using Standard Device Interface (SDI-12) communication
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protocol. The SDI-12 communication protocol assigns individual addresses to each submersible

sensor, simplifying the retrieval and storage of data.

Versatility was a primary requirement in selecting the data logger. It was necessary that the data

logger collect and store data from several sensors, have the capability to be programmed and to

transmit data over the cellular-phone connection, and transmit stored data once a day by GOES

(Geostationary Orbiting Environmental Satellite) transmitter. The data logger was programmed to

store data values hourly and transmit the data daily.

Data Transmission and Storage

USGS personnel can query and retrieve data from the data logger using the cellular telephone.

Programming instructions and data corrections can also be sent by telephone. Without this capability

and because of restricted access to the OB/OD area, the quality of the data could be less than

satisfactory.

The U.S. Army at Ft. Riley limits transmissions at the OB/OD area so that there are no unexpected

radio transmissions that could interfere with the demolition of ordnance. For this reason, a timer

activates the cellular telephone for troubleshooting, reprogramming, or data retrieval between

midnight and 1:00 a.m. The timer and cellular telephone are powered independently of the DCP so

that the DCP can be programmed even if it stops functioning properly.

The DCP transmits hourly data once a day during a 2-minute window around midnight. The data are

received by a USGS ground station and transmitted to the USGS office in Lawrence.

Preliminary Data

Currently (March 1998), data are being collected from piezometers and monitoring wells at the

OB/OD area. Data collection at two piezometers began in September 1997. Collection at the third

piezometer and the three monitoring wells began in December 1997.

Preliminary ground-water measurements from a piezometer are shown in figure 3. The observed

ground-water-level fluctuations in the piezometer may be related to changes in barometric pressure

and to flucutations of the water level in the aquifer. An increase in barometric pressure causes water

levels in the piezometer to decline, whereas a decrease in barometric pressure has the opposite effect

(fig. 3). This is typical of ground-water response in confined aquifers.

Figure 3. Hourly ground-water levels measured in a piezometer and mean daily

barometric pressure measured at the Manhattan, Kansas Municipal Airport, September-December

1997. Ground-water-level data on file with U.S. Geological Survey, Lawrence, Kansas. Barometric

pressure obtained from the National Climatic Data Center, Asheville, North Carolina.

For more information please contact:

District Chief 

U.S. Geological Survey 

4821 Quail Crest Place 

Lawrence, Kansas 66049-3839 
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(785) 842-9909 

email: waucott@usgs.gov