Letter_Report_Fish_Barrier_Sparking_(2005-05-31)_report.pdf

ERDC/CERL LR-05-2 May 2005

ENGINEERING ANALYSIS OF THE CHICAGO SANITARY AND SHIP CANAL

ELECTRIC FISH BARRIER: ELECTRICAL EFFECTS ON BARGES AND TOW

VESSELS

Vincent Hock, Michael McInerney, James Bushman, Tarek Abdallah, Paul Nielsen, Thomas Lilly, Charles Shea, and Tad Britt

US Army Engineer Research and Development Center Construction Engineering Research Laboratory

PO Box 9005 Champaign, IL 61826-9005

ERDC/CERL Letter Report LR-05-2 May 2005

ENGINEERING ANALYSIS OF THE CHICAGO SANITARY AND SHIP CANAL

ELECTRIC FISH BARRIER: ELECTRICAL EFFECTS ON BARGES AND TOW

VESSELS

BACKGROUND

The US Army Corps of Engineers Chicago District is operating a temporary electric field-based fish barrier in the Chicago Sanitary and Ship Canal, Romeoville, Illinois. The barrier was constructed by Smith-Root Inc, sole licensees of the U.S. patent (Smith 1988), to prevent the encroachment of invasive species, such as the Asian Carp (Rasmussen 2001) into the Great Lakes. The barrier had been in operation for a little more than two years when, in May 2004, an electrical discharge-related incident in the vicinity of the barrier was reported. This incident involved tow assembly operations over or very near the barrier. During preliminary discussions between ERDC-CERL, the Coast Guard, and the Chicago District, it was emphasized that it is crucial to prove this type of barrier is safe for barge and boat operation.

The barrier consists of two electrode arrays (uninsulated metal conductors) perpendicular to the water flow and near to the bottom of the canal. A high voltage pulse applied between the electrodes creates an electric field in the water. Fish receive progressively higher voltage shocks as they approach and attempt to cross the electric field generated by the barrier, so they turn away from it. At the time of testing, the electrode arrays were configured to pulse simultaneously with a 4 ms (millisecond) pulse width, five times a second, with opposite polarities. The pulse width of 4 ms and ‘off’ duration of 196 ms results in a 2% duty cycle.

ERDC-CERL is grateful for the assistance of Illinois Marine Towing and Garvey Marine, who provided barges, towboats, and crews for the barge measurement exercises; and the assistance of the Chicago District, who provided the Boston Whaler and pilot for the field mapping exercises. Individual acknowledgements are listed the Acknowledgements section of this report.

OBJECTIVE

ERDC-CERL proposed to support the Chicago District by conducting electric field measurements to determine the magnitude of electrical potential buildup for various barge and hull configurations passing over the barrier. Separate measurements would be made to map the electric field downstream, within, and upstream from the barrier. The objective of these tests was to determine:

• The physical extent of the electric field generated by the fish barrier.

• The amount of polarization or voltage buildup on a boat or barge as the boat or barge passes over the barrier. These measurements were intended to identify and quantify any voltage buildups during normal barging operations.

• The possible potential or voltage differences within a barge tow and between a barge tow and earth ground in different configurations inside and outside the fish barrier perimeter. These measurements were intended to determine if the potential exists for static electrical discharge between barges and boats.

APPROACH

In order to address these objectives, ERDC-CERL, in conjunction with representatives of the Chicago District and the U.S. Coast Guard, developed the following tasks.

1. Map the electric field resulting from operation of the barrier (first objective).

2. Measure voltage potentials between the components of a tow passing through the barrier, for three typical tow configurations (third objective).

3. Measure voltage potentials between a tow passing a moored barge while in the barrier (third objective).

4. Measure voltage potentials between a tow and a moored barge, while the tow is approaching the moored barge over the barrier (third objective).

5. Measure voltage potentials between a tow and the barrier system ground while the tow is traversing the barrier (third objective).

6. Measure the voltage potentials between electrically isolated stationary barges while one is parked over the barrier (task added by Project Leader during testing).

7. Measure and quantify of the degree of barge and tow electrical potential buildup on the hull while traversing the barrier (second objective).

8. Measure the electrical continuity between the engine drive shaft and engine block of a typical towboat (task added by Coast Guard during testing).

The experiments were conducted in two periods, between 5 and 7 January 2005 and between 2 and 3 March 2005. Environmental data are listed in Table 1. The conductivity of the canal water (500 ppm TDS) during the experiments was only slightly higher than typical Midwest potable water.

The January tow measurements were made with the aid of the “Albert C” owned by Illinois Marine Towing. This boat was not available for the March measurements and the “Joe Avery” owned by Garvey Marine was used for parallel barge configuration measurements. Experiments were conducted along various routes in the canal (i.e. east bank, center, west bank, upstream, downstream) in order to completely survey the influence of the fish barrier. Barges were fully loaded to maximize hull exposure in the water.

The magnitude (absolute value) of the measured value is significant for this analysis. Except for task 7, the sign (positive or negative) of the measurement is unimportant. For these experiments, the sign was determined arbitrarily, based solely upon which lead was connected to the common (reference) terminal of the instrument. Instrument connections were selected for expediency and convenience, not for physical reasons. Instrumentation is described in more detail in Annex 1.

Task 1 - Map the electric field

Experimental Approach

To measure the extent of the fields generated by the barrier electrodes, an array of reference electrodes was attached to a “Boston Whaler” fiberglass boat supplied by the Chicago District. A small fiberglass boat was selected for the field strength measurements in order to minimize field perturbations that could be caused by a metal-hulled boat and to allow reasonable maneuverability. Neither would have been possible using a relatively large towboat. The system utilized highly accurate (±1 millivolt typical) reference electrodes (saturated Ag-AgCl electrodes) as sensors. The electrodes were mounted to a wood framework clamped to the fiberglass boat in a grid configuration (Figure 1). The array was both expedient and allowed for on-site construction that could be custom fit to the fiberglass boat hull. A wood-framed transparent polyethylene-covered instrumentation shelter was custom fabricated on-site because many of the measurements were gathered during inclement weather conditions, including both snow and sleet. Nine runs were made, three along each bank of the canal and three in the center.

As the boat traveled over the barrier, simultaneous measurements of the voltage between adjacent cells defined the static and transient electric field gradients in the canal at four depths. In addition to within the barrier itself, electric field measurements were taken several hundred feet both up and downstream from the barrier to determine the full extent of the field. These measurements were used to assess the likelihood of developing a great enough voltage difference both at the water surface and at several depths to cause a discharge between hulls or barges.

A diagram of the measurement system is shown in Figure 1. The horizontal electric field at four depths (1, 4, 7, and 15 feet) was measured by half-cells spaced 16-ft, 8-in. apart horizontally (determined by the length of the boat). The voltage between the half-cells divided by the separation distance gives the horizontal electric field in volts/inch.

The Agilent, with its multiple channel input capability, was used to simultaneously measure and record the peak values between each pair of reference electrodes separated 16-ft 8-in. (200-in.) apart and set at depths of 1, 4, 7, and 15 feet, while the Fluke 865 with its single channel capability was connected to the pair of electrodes set at the 7-ft depth. Annex 1 provides more details on the instrumentation.

Results

Figure 2, Figure 3, Figure 4, and Figure 5 show typical data of the horizontal electric field at selected depths in the canal. The location of the fish barrier electrode array is identified by the vertical “dashed” lines on each graph. At all depths, the peak electric field gradient within the barrier is 100 to 120 volts.

Because the fish barrier consists of two arrays, the fields generated by the arrays can add either constructively (positively) or destructively (negatively), thus resulting in a complex waveform.

The maximum fields occurred within the barrier region. The peak values at each depth were fairly consistent, confirming that the fish barrier operation was satisfactory. The voltages dropped below measurable values when the reference electrodes were more than 450 feet from the barrier in either direction.

Sparking can occur when there is a large electrical potential difference between objects. So to minimize the chance of sparking, the objects should be at nearly equal potentials. The measured electric fields became fairly uniform at 350 feet from the barrier, so the potential difference (and possibility for sparking) at this location and beyond is extremely small. Based on this data, ERDC-CERL recommends that ±350 feet from the center of the barrier be used as the minimum distance for the Coast Guard regulations (Annex 2) to apply.

Task 2a - Measure the voltage potentials between the components of a tow, barges in series connected with soft line (i.e., nylon or hemp rope)

Experimental Approach

To evaluate the possibility of sparking between two barges that were not adequately electrically connected, an experiment using the instrumented barge configuration shown in Figure 6 was performed with the barges connected with soft line and electrically isolated by a soft line. (A soft line was hung between the barges to maintain electrical isolation.) Voltages V1 and V2 were measured. Two runs across the barrier were conducted, one upstream and one downstream.

Results

As shown in Figure 7, while the barge separation was only 1 to 2 inches, the maximum voltages measured between the two barges approached 250 volts as the tow moved over the barrier. Note that this plot uses the position of the front of the tow as its reference. Therefore, the peak values are offset from the barrier by the length of the barge and towboat. The maximum negative value occurs when the front of the leading barge is about 200 feet downstream of the barrier, which is when the first barge is leaving and the second barge is entering the barrier.

Task 2b - Measure the voltage potentials between the components of a tow, barges in series connected with wire rope (i.e., steel cable)

Experimental Approach

These measurements were made using the instrumented barge configurations shown in Figure 6 and the barges were connected with wire rope. Voltages V1 and V2 were measured. Four runs across the barrier were conducted, two upstream and two downstream.

Results

Barge-to-barge (V1) and barge-to-towboat (V2) potentials were measured. Figure 8 was generated from data gathered between wire contact points on the end of the barge farthest from the towboat (two barges and towboat all in tandem) with the other contact point on the towboat (the barges and towboat were all cabled together with steel hawsers). Since this measurement included the maximum length of steel exposed during these runs, the voltages measured were the highest recorded for wire-roped tows.

Nevertheless, the measured values were all less than 0.15 volt.

Figure 9 shows the voltages measured from barge-to-barge contact points. Since this included a shorter metal path than that produced in Figure 8, the data also generated lower overall voltages and almost all of the peak pulses were less than 0.1 volt.

Note that these voltages are more than three orders of magnitude (1000 times) less than the peak voltage measured for the soft line configuration, 0.15 volt versus 250 volts. Therefore sparking is extremely unlikely for wire-rope in-line tows.

Task 2c - Measure the voltage potentials between the components of a tow, barges in parallel connected with wire rope (i.e., steel cable)

Experimental Approach

These measurements were made using the instrumented barge configurations shown in Figure 10. All barge and tow connections were made with wire rope. The experiments illustrated in these figures were used to determine the voltages V1 and V2. Three runs were made, two downstream and one upstream.

Results

Barge to towboat potentials were measured using the Agilent and the Tektronix. Figure 11 and Figure 12 show voltages resulting from the parallel barge tests. Note the similarity between the two plots. This is to be expected as the parallel barges are exposed to identical barrier voltages and they are electrically connected with steel cables. Although the maximum potentials are higher than for the series configuration, 3 volts versus 0.15 volt, they are still low enough to make sparking unlikely. Note also that the peak voltages are nearly two orders of magnitude (100 times) less than the peak voltage measured for the soft line in-line configuration. Therefore sparking is extremely unlikely for wire-rope parallel tows.

It was not possible to perform soft-line connected tests for the parallel configuration because the towboat must connect to the barges with wire rope.

Task 3 - Measure the voltage potentials between a tow passing a moored barge while in the barrier.

Experimental Approach

To determine the possibility of sparking between a stationary and moving barge one barge was moored approximately 40 feet downstream from the fish barrier. Electrical potential measurements were made between the fixed and moving barge, V1 in Figure 13, while the moving tow passed over the barrier.

Results

Figure 14 shows that the potential difference between a barge moored near the barrier and a barge approaching and then passing. The potential decreases from a maximum of over 300 volts to voltages near zero. This great reduction in voltage is not unexpected since both barges, when side by side, are at equal field potentials.

Task 4 - Measure the voltage potentials between a tow and a moored barge, while the tow is approaching the moored barge over the barrier.

Experimental Approach

To determine the possibility of sparking between a stationary and moving barge, one barge was moored approximately 40 feet downstream from the fish barrier. A second barge with tow was then maneuvered toward the moored barge from the opposite side of the barrier until it touched the fixed barge. Electrical potential measurements were made between the fixed and moving barge, V3 in Figure 15.

Results

As can be seen in Figure 16, the potential difference between two barges when one is approaching the other end-on-end decreases with decreasing distance, but not to zero. Instead, as the distance decreases to the point where they are virtually touching, the voltage still remains in excess of 40 volts. This represents a worst-case condition and a situation that almost assures sparking. The lower barrier limit is not shown on this plot because it is just outside (at 36 feet) the upper limit of the zoomed range of this plot.

Task 5 - Measure the voltage potentials between a tow and the barrier system ground while the tow is traversing the barrier.

Experimental Approach

To ascertain the voltage difference between a tow passing through the fish barrier and the earth ground adjacent to the canal (V3 in Figure 6), one test lead was connected to the barge and the second test lead was connected to the fish barrier earth grounding system through a custom-fabricated cable reel system with slip rings.

Results

As shown in Figure 17, the peak voltages between the barge and the earth grounding system exceeded 80 volts. Thus, if a barge were to stop and attempt to moor to an existing metallic bollard using a steel mooring cable, a significant risk of sparking could occur, and if a successful mooring was completed with no further observable incident, the stray currents generated by the fish barrier system while the barge was held in this fixed position could generate significant hull damage due to electrolytic corrosion.

These results definitely showed that large potentials can be developed between the barge and shore, so additional measurements for the parallel configuration were considered unnecessary.

Task 6. Measurement of voltage potentials between electrically isolated stationary barges while one is parked over the barrier.

Experimental Approach

Two barges were electrically isolated with soft lines to prevent electrical contact. One barge was moored just downstream from the barrier with the other barge located over the barrier. The voltage between the two barges was measured.

Results

While configuring the tow for the in-line experiments, sparking between barges was observed. One barge was moored slightly downstream of the barrier while the other barge and towboat were over the barrier.

Sparking was created when a metal tool used for connecting the barges was used to bridge the barges. As the tool was scraped across one of the barge surfaces, sparks were created. Large sparks were also observed when the hull corners of the roped together barges made contact.

Voltage measurements were made between the two barges while they were electrically separated by a soft line. The voltage waveform in Figure 18 was recorded using the Tektronix. This recording is not georeferenced since the barges were not in motion. The graph shows peak open circuit voltages of approximately 20 volts.

It is important to note the very low voltage at which the sparking occurred. This voltage is not great enough to break down the air and initiate an arc. Therefore, the sparking occurs because, when metal objects (e.g. barges or wire rope) touch while one is over or very near the barrier, current flows between them due to the differing potentials. The sparks occur when the current flow is interrupted, similar to opening a switch in an electrical circuit – current does not want to be interrupted and so continues to flow as the switch opens.

These observations support the conclusion that tows should not be made up within the vicinity (±350 feet) of the fish barrier. The operation of breaking tows involves separating barges. When the barges separate sparking will occur. During the operation of making tows as the barges bounce around and scrape together sparking will occur. Sparking may also occur when a wire rope is passed from one barge to the other.

Task 7. Measure and quantify barge and tow electrical potential buildup

Experimental Approach

In order to evaluate whether the fish barrier increased barge hull corrosion rates, hull voltage buildups were determined by measuring the electrical potential difference between reference electrodes mounted on the corners of the barges and the steel hull adjacent to the electrode (measurement V4 in Figure 6).

The measurements were made during several passes over the barrier by the tow.

Results

Figure 19 is a representative plot of hull-to-electrode potential while traversing the barrier. To mathematically assess the above visual observation, the average value measured during each run was calculated and then this average was divided by the total variation measured in each run which was expressed as a percentage of the total variation. These calculations indicate that the average for all hull-to-cell values was less than -0.057 volts referenced to a Ag-AgCl electrode.

The analysis confirms that the hull to electrode potentials have a nearly perfect “net zero” value, confirming that the fish barrier electrical signal results in effectively inducing an AC signal during the cycle of the vessel entering, passing over, and leaving the barrier. Thus, so long as it is the practice to enter, pass through, and continue beyond the barrier by at least several hundred feet at a relatively uniform rate, no long-term corrosion effects should be of concern for the vessels operating through the fish barrier.

Task 8. Measure electrical continuity between the engine drive shaft and engine block of a typical towboat

Experimental Approach

While the towboat was stationary over the barrier, the electrical resistance between the engine drive shaft and engine block was made with a Volt/Ohm meter. One engine was shut down and the measurements were made by contacting one lead to the drive shaft and the other to the engine block.

Results

The electrical resistance between the engine drive shaft and engine block was 0.2 ohm. This indicates that the engine block, transmission, and drive shaft are electrically continuous. Therefore, sparking between the drive shaft and engine block is unlikely.

CONCLUSIONS

Personnel from ERDC-CERL conducted a variety of measurements near and over the barrier that showed that simple adherence to existing regulations and common practices will ensure safe operation of conventional barging operations.

Task 1. Immediately outside the outermost electrodes on either side of the barrier, the field strength decays dramatically (Figure 2 through Figure 5). The pulses generated by the barrier system can be detected up to 450 feet away on either side of the array. Based on this data, the region 350 feet upstream and downstream from the center of the barrier (a total of 700 feet along the canal) has been designated as having an electric field strength strong enough to create sparking under certain circumstances.

Regulations prohibiting mooring, assembly and disassembly of tows, and passing of barges are to be enforced in this region. While pulses generated by the barrier can be detected up to 450 feet away from the outermost electrodes, the field strength is very low and changes very slowly. Therefore, sparking in this region is highly unlikely.

Task 2. Since the measured voltages were quite low, ERDC-CERL concludes that the possibility of sparking is remote for wire-roped tows. Wire rope is generally preferred over soft line for towing operations because it allows the elements of the tow to become more electrically common while traversing the barrier region. Tows with parallel-configured barges accumulate higher voltage when entering the barrier region because more hull area is exposed to the field. Sparking is still unlikely if these tows are tied using wire ropes. The very high voltages observed for soft lines indicates that sparking is more probable when soft lines are used to tie barge components.

Task 3. When parallel tows pass each other in the barrier region, the possibility of sparking remains low.

Should elements of two different tows somehow become electrically connected (e.g., a wire rope is tossed between them), the electric potential difference between the elements could be high enough to create a spark. In addition, should elements from separate tows scrape against each other in the barrier region, the possibility of sparking is substantial.

Task 4. The potential difference between two barges—one moored near the barrier, the other approaching over the barrier—decreases with decreasing distance but does not decrease to zero. Instead, as the distance decreases to the point where they are virtually touching, the voltage still remains in excess of 40 volts. This represents a worst-case condition and a situation which almost assures sparking. Regulations should be enforced prohibiting making or breaking of tows in the barrier region (approximately 350 feet upstream and downstream from the outermost electrodes).

Task 5. If a barge were to stop and attempt to moor to an existing metallic bollard using a steel mooring cable, a significant risk of sparking could occur. If a successful mooring was completed with no observable incident, the stray currents generated by the fish barrier system while the barge tow was held in this fixed position could generate significant hull damage due to electrolytic corrosion.

Task 6. Peak voltages of approximately 20 volts were measured between a moored barge and barge parked over the barrier. Sparking was observed when electrical contact between the barges was broken.

Sparking can occur between elements of a tow or between a wire rope and barge when these elements are not at the same electrical potential because of their positions within the fish barrier. Although the voltage difference is not enough to initiate arcing, as these elements separate, the current flow tends to continue across the ionized air separating the elements (creating sparks). While these elements were in physical contact current, generated by the fish barrier, flowed between them. This phenomenon can be compared to an electric switch that is opened while current is flowing through it. Electrical contact between barges and towboats should not be broken or made (i.e. tows should not be made or broken) within the vicinity of the fish barrier.

Task 7. Analysis confirms that the hull-to-electrode potentials have a nearly perfect “net zero” value confirming that the fish barrier electrical signal results in effectively inducing an AC signal during the cycle of the vessel entering, passing over, and leaving the barrier. Thus, so long as it is the practice to enter, pass through, and continue beyond the barrier by at least several hundred feet at a relatively uniform rate, no long-term corrosion effects should be of concern for the vessels operating through the fish barrier.

Task 8. The engine block, transmission, and drive shaft of a typical towboat are electrically continuous.

Therefore, sparking between the drive shaft and engine block is unlikely.

The overall conclusions of this part of the study are:

• The extent of the barrier's influence is about 700 feet (350 feet up- and downstream)

• Wire rope connections on tows are preferred, soft line connections are bad

• No passing in vicinity of barrier

• No making/breaking tows in vicinity of barrier

• No mooring in vicinity of barrier

• Corrosion of barges and towboats not a problem in passage

• Sparking within towboat between propeller shaft and engine block not a problem

RECOMMENDATIONS

The U.S. Coast Guard based their temporary rules and regulations for tows operating in the vicinity of the electric fish barrier (Annex 2) on ERDC-CERL’s preliminary observations and analyses. We now recommend that the Coast Guard make these rules permanent.

REFERENCES

Rasmussen, J.L. 2001, The Cal-Sag and Chicago Sanitary and Ship Canal: A Perspective on the Spread and Control of Selected Aquatic Nuisance Fish Species, U.S. Fish and Wildlife Service, 4469 - 48th Avenue Court, Rock Island, IL 61201, 26 pp.

Smith; David V., Fish repelling apparatus using a plurality of series connected pulse generators to produce an optimized electric field, United States Patent 4,750,451 June 14, 1988.

ACKNOWLEDEMENTS

Chicago District Corps of Engineers Charles Shea, Project Manager Whaler (23 November 2005) Sinko Higgins Whaler (5 January 2005) Melvin McLaurin

Illinois Marine Towing, Lemont Illinois M/V Albert C towboat (6 – 7 January 2005) Capt Bill Russell Pilot Richard Robertson Crew David Jones

Garvey Marine Towing, Lemont Illinois Joe Avery towboat (3 March 2005) Captain James Janes Crew Manuel Santos and Matt Cupples

FIGURES

FIGURE 1. Electric field gradient measurement technique.

Voltage Difference of Half-Cells Immersed at 15 Feet, Horizontal whaler traveling upstream in center of canal

-20

-10

-450 -350 -250 -150 -50 50 150 250 350 450 550

Distance of Center of Whaler from Center of Barrier (feet)

Vo lta ge D iff er en ce

(v ol ts

Agilent

B ar rie r

2005/01/05 Field Mapping, run 9

FIGURE 2. Horizontal electric field measured at a 15-foot depth.

Voltage Difference of Half-Cells Immersed at 7 Feet, Horizontal

-20

-10

-450 -350 -250 -150 -50 50 150 250 350 450 550

Distance of Center of Barrier from Center of Barrier (feet)

Vo lta ge D iff er en ce

(v ol ts

Agilent Scaled Fluke 865

2005/01/05 run 9, Field Mapping

B ar rie

FIGURE 3. Horizontal electric field measured at a 7-foot depth.

Voltage Difference of Half-Cells Immersed at 4 Feet, Horizontal

-20

-10

-450 -350 -250 -150 -50 50 150 250 350 450 550

Distance of Center of Whaler from Center of Barrier (feet)

Vo lta ge D iff er en ce

(v ol ts

Agilent

2005/01/05 run 9, Field MappingB ar

FIGURE 4. Horizontal electric field measured at a 4-foot depth.

Voltage Difference of Half-Cells Immersed at 1 Foot, Horizontal whaler traveling upstream in center of canal

-20

-10

-450 -350 -250 -150 -50 50 150 250 350 450 550

Distance of Center of Whaler from Center of Barrier (feet)

Vo lta ge D iff er en ce

(v ol ts

Agilent

2005/01/05 run 9, Field MappingB ar

FIGURE 5. Horizontal electric field measured at a 1-foot depth.

FIGURE 6. Tow in two-barge series (in-line) configuration.

Potential (voltage) Difference between Barges soft line connection tow traveling downstream (towboat pushing)

-300

-250

-200

-150

-100

-50

-750 -650 -550 -450 -350 -250 -150 -50 50 150 250 350 450 550

Distance of Front Barge Bow from Center of Barrier (feet)

Po te nt ia l D iff er en ce (v ol ts

Agilent

2005/01/07 run 2, In-line Barges

B ar

FIGURE 7. Potential difference between two barges, in-line configuration, while traversing the barrier (V1 in FIGURE

6).

Potential (voltage) Difference between Barge and Tow wire cable connections tow traveling downstream (towboat pushing)

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

-900-800-700-600-500-400-300-200-1000100200300

Distance of Front Barge Bow from Center of Barrier (feet)

Po te nt ia l D iff er en ce (v ol ts

Agilent

B ar rie

2005/01/06 run 3, In-line Barges

FIGURE 8. Potential difference between barge and towboat while traversing the barrier (V2 in FIGURE 6).

wire cable connections tow traveling downstream (towboat pushing)

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

-900-800-700-600-500-400-300-200-1000100200300

Distance of Front Barge Bow from Center of Barrier (feet)

Po te nt ia l D iff er en ce (v ol ts

Agilent

B ar rie

2005/01/06 run3, In-line Barges

FIGURE 9. Potential difference between two barges, in-line configuration, while traversing the barrier (V1 in FIGURE

6).

FIGURE 10. Tow in two-barge parallel configuration.

Potential (voltage) Difference between Port Barge and Tow tow traveling downstream (towboat pushing)

-5

-4

-3

-2

-1

-600-500-400-300-200-1000100200300400

Distance of barge bow from center of barrier (feet)

Po te nt ia l D iff er en ce (v ol ts

Agilent

2005/03/03 run3, Parallel Barges

B ar

FIGURE 11. Potential difference between port barge and towboat while traversing the barrier (V1 in FIGURE 10).

Potential (voltage) Difference between Starboard Barge and Tow tow traveling downstream (towboat pushing)

-5

-4

-3

-2

-1

-600-500-400-300-200-1000100200300400

Distance of barge bow from center of barrier (feet)

Po te nt ia l D iff er en ce (v ol ts

Agilent

2005/03/03 run 3, Parallel Barges

B ar

FIGURE 12. Potential difference between starboard barge and towboat while traversing the barrier (V2 in FIGURE 10).

FIGURE 13. A tow consisting of a single barge and towboat passing a barge parked near the barrier.

Potential (voltage) Difference between Passing Barge and Moored Barge tow traveling downstream (towboat pushing)

-350

-300

-250

-200

-150

-100

-50

-40.00-20.000.0020.0040.0060.0080.00100.00

Distance between bows of barges (feet)

Po te nt ia l ( vo lts

Agilent Fluke 105B

2005/01/07 run 3, Barges PassingBarrier

FIGURE 14. Potential difference between barges while passing over the barrier (V1 in FIGURE 13).

FIGURE 15. A tow consisting of a single barge and towboat approaching a parked barge adjacent to the barrier.

Potential (voltage) Difference between Docking Barge and Moored Barge tow traveling downstream over barrier (towboat pushing)

-400

-350

-300

-250

-200

-150

-100

-50

051015202530

Distance between barges (feet)

Po te nt ia l ( vo lts

Agilent Fluke 105B

2005/01/07 run 4, Barges Docking

FIGURE 16. Potential difference between two barges when approaching each other, one over the barrier (V3 in FIGURE

15).

Potential (voltage) Difference between Barge and Shore wire cable connections tow traveling upstream (towboat pulling)

-100

-80

-60

-40

-20

-400 -200 0 200 400 600 800

Distance of Tow boat stern from barrier (feet)

Po te nt ia l ( vo lts

Agilent

Fluke 105B

2005/01/07 run5, Barge-to-Shore Potential

B ar

FIGURE 17. Potential between the barge and shore (earth ground) while passing over the barrier (V3 in FIGURE 6).

soft-line connection barges stationary, one parked over barrier

-5

13 14 15 16 17 18 19

Time (seconds)

Po te nt ia l D iff er en ce (v ol ts

Tektronix

2005/01/07 run 0, Stationary Barges

FIGURE 18. Barge to barge voltage; stationary barges, rope connections (V1 in FIGURE 6).

Barge Hull Potential, Starboard Side wire cable connections tow traveling upstream (towboat pulling)

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

-500 -400 -300 -200 -100 0 100 200 300

Distance of Stern of Tow from Center of Barrier (feet)

H ul l P ot en tia l ( vo lts

Fluke 865

2005/01/06 run 4, In-line Barges

B ar

FIGURE 19. Variation in barge hull potential while traversing the barrier (V4 in FIGURE 6).

TABLES

TABLE 1. ENVIRONMENTAL CONDITIONS DURING FIELD TESTING

Date Mean

Temperature (°F)

Maximum Temperature

(°F)

Average Humidity

Precipitation (in)

Wind Speed (mph)

Water Conductivity (ppm TDS [µS/cm])

5 January 2005 30 32 92 .03 Snow 20 500 (780) 6 January 2005 22 30 89 .03 Snow 12 500 (780) 7 January 2005 19 28 89 .00 6 500 (780) 2 March 2005 20 28 65 .00 7 500 (780) 3 March 2005 26 37 67 .00 4 500 (780)

ANNEX 1 - INSTRUMENTATION

Various models of multimeters, digital storage oscilloscopes and data acquisition units were used to record the electrical measurements.

1) Agilent 34970A Multiplexing Data Acquisition System with up to 20 analog to digital DC voltage input channels.

2) Tektronix 5104 Digital Phosphor Oscilloscope

3) Fluke 105B Digital Scopemeter with 100 MHz Bandwidth

4) Fluke Model 865 Graphical Volt/Ohm meter

5) Hewlett Packard E2373A Volt/Ohm meter

6) Garmin N-17 GPS receivers with TDS Recon Hand-held computers

7) ARMS enhanced ike 300

The Agilent Data Acquisition System was used throughout the experiments to continuously measure and record the voltage differentials. The Agilent was chosen because of its multiple independent channel capabilities (up to six for these experiments) and its virtually limitless storage. (When used in conjunction with a personal computer (PC) data is immediately transferred to the PC for storage.) The disadvantage of using the Agilent was not being able to synchronize measurements with the fish barrier pulses. Since the instrument was free running there was no guarantee that every pulse or even that a complete pulse was captured. This is why the magnitudes of the peaks do not change monotonically.

Fortunately because of the high sample rate and long scan times, complete pulses were frequently obtained. When interpreting the Agilent data, the envelope (overall trend of the peak values) of the waveform should be considered.

The Flukes and the Tektronix were used as backups in case of failure of the Agilent and as a secondary confirmation of the measurement. The Agilent, Fluke 105B and Tektronix are direct reading and recording systems. The Fluke Model 865 is a direct reading and average recording instrument. Since the Fluke Model 865 collects and averages the measurements over a 1 second time period, it would average the single 4 ms “pulse peak” values with the “off” voltage values, resulting in an under recording of the peak values. Because the barrier pulses have a 2% duty cycle, the average value of the Fluke 865 must be scaled by factor of 50 (1/.02) to convert to peak value.

Throughout the project all moving electrical measurements were collected and referenced with geospatial coordinates to aid in mapping and determining the extent and nature of the electrical field. Two Global Positioning Systems (GPS) were used to record the data. These were typically placed on the bow and stern of the “Boston Whaler” as well as the barge configuration. GPS location was recorded at 0.2-ft to 20-ft intervals, depending on the measurement system, as the reference cell array passed over the electrodes of the electric fish barrier.

The GPS recorded its position every two or three seconds. Because the data acquisition instruments recorded voltages at millisecond intervals, in order to georeference the electrical data a linear interpolation of the GPS data was required. The electrical measurements were georeferenced by using the barrier array as a marker. Because the maximum electrical measurement values occur over the barrier, the time values of the measurement files were georeferenced by synchronizing the time of the maximum values with the time of the location of the barrier arrays in the GPS files.

ANNEX 2 – U.S. COAST GUARD REGULATED NAVIGATION BROADCAST FOR BARGE

OPERATIONS IN THE VICINITY OF THE ELECTRIC FISH BARRIER

Federal Register / Vol. 70, No. 16 / Wednesday, January 26, 2005 / Rules and Regulations /

§ 165.T09—001 Temporary Regulated Navigation Area between mile markers 296.1 and

296.7 of the Chicago Sanitary and Ship Canal located near Romeoville, IL.

(a) Location. The following is a Regulated Navigation Area: All waters of the Chicago Sanitary and Ship Canal, Romeoville, IL beginning at the north side of Romeo Road Bridge Mile Marker 296.1, and ending at the south side of the Aerial Pipeline Mile Marker 296.7.

(b) Effective Period: This rule is effective from 3 p.m. (CST) January 13, 2005 until 12 p.m. (CST) June 30, 2005.

(c) Regulations

(1) The general regulations contained in 33 CFR 165.13 apply.

(2) All vessels are prohibited from loitering in the vicinity of the electrical dispersal barrier. ‘‘Vicinity’’ of the electrical dispersal barrier is defined as the Chicago Sanitary and Ship Canal from the north side of the Romeo Highway Bridge at Mile Marker 296.1 to the aerial pipeline arch located at Mile Marker

296.7. Vessels may enter this section of the waterway with the sole purpose of transiting to the other side, and must maintain headway throughout the transit. All personnel on open decks must wear a Coast Guard approved Type I personal flotation device while in the ‘‘vicinity’’ until subsequent field testing determines the waters in this area do not pose significant risk to human life. Vessels may not moor or lay up on the right or left descending banks. Towboats may not make or break tows. Vessels may not pass (meet or overtake) in the ‘‘vicinity’’ and must make a SECURITE call when approaching the barrier to announce intentions and work out passing arrangements on either side. Commercial tows transiting the barrier must be made up with wire rope to ensure electrical connectivity between all segments of the tow.

(3) All persons and vessels shall comply with this rule and any additional instructions of the Ninth Coast Guard District Commander, or his designated representative.

Dated: January 13, 2005.

R.J. Papp, Rear Admiral, U.S. Coast Guard, Commander, Ninth Coast Guard District.

[FR Doc. 05–1425 Filed 1–25–05; 8:45 am]

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