Chickamauga DamNavigation Lock Project

TENNESSEE VALLEY AUTHORITY

Chickamauga Dam--Navigation Lock Project

AGENCY: Tennessee Valley Authority.

ACTION: Issuance of record of decision.

-----------------------------------------------------------------------

SUMMARY: This notice is provided in accordance with the Council on

Environmental Quality's regulations and with TVA's procedures

implementing the National Environmental Policy Act. TVA has decided to

adopt the preferred alternative identified in TVA's final environmental

impact statement (EIS) made available to the public on March 26, 1996.

A Notice of Availability of the final EIS was published in the Federal

Register on April 5, 1996 (61 FR 15252). The preferred alternative is

to construct a new 110 x 600 foot lock to replace the existing lock at

Chickamauga Dam. Because of structural problems and safety concerns

caused by concrete growth, the existing lock at Chickamauga Dam has a

limited life expectancy, at most 10 years. TVA will continue to monitor

the existing lock and make the necessary repairs to keep the lock in

operation until the new lock is available for service. Design and

construction of the new lock, subject to available funding, are

expected to begin five years prior to closure of the existing lock.

This will allow the new lock to be operational before the existing lock

is closed, thereby maintaining navigation on the upper Tennessee River.

FOR FURTHER INFORMATION CONTACT:

W. Gary Brock, Manager, Water Resources Projects and Planning,

Tennessee Valley Authority, West Tower 10C-432, Knoxville, Tennessee

37902, or by calling (423) 632-8877.

SUPPLEMENTARY INFORMATION: The Tennessee River is formed at the

confluence of the Holston and French Bread Rivers near Knoxville in

eastern Tennessee. From this confluence, the river flows 652 miles

through Tennessee, northern Alabama, northeastern Mississippi, and

western Kentucky to enter the Ohio River near Paducah, Kentucky. Along

most of its counsel, the river falls gradually for a total of 515 feet

except in the Muscle Shoals, Alabama, area where a drop of 100 feet

occurs in less than 20 miles.

The existing navigation system on the Tennessee River consists of

nine multipurpose dams and lock projects with a total of 13 navigation

locks. The system creates a series of navigation pools that provide a

nine foot navigable channel along the entire length of the river except

for a three mile stretch at Knoxville where, in periods of low water,

the depth diminishes to seven feet and the channel width diminishes to

about 200 feet. Navigation locks on the Tennessee River range in size

from 110 x 1000 foot lock at Pickwick Dam to 60 x 300 foot double lift

auxiliary lock at Wilson Dam.

The upper Tennessee River navigation system begins at Chickamauga

Dam, river mile 471, and extends 181 upstream to the confluence of the

Holston and French Broad Rivers. The system consists of four navigation

locks located at Chickamauga, Watts Bar, Fort Loudoun, and Melton Hill

dams. The four locks were constructed in 1937, 1941, 1942 and 1963

respectively. The predominant commodities trafficked on the upper

Tennessee River system are asphalt, grains, ores and minerals, and

forest products.

TVA's Chickamauga Dam and Navigation Lock Project is located in

Hamilton County, Tennessee, approximately 13 miles northeast of

downtown Chattanooga, Tennessee. Chickamauga Lock currently has a

traffic level of about 2.1 million tons per year.

TVA and the United States Army Corps of Engineers (USACE) began

studying navigation problems on the upper Tennessee River in 1987. The

study results were published in 1988 by the Nashville District of the

USACE in a report entitled, Commodity Traffic and Benefit Study for

Navigation Improvements on the Upper Tennessee River. Both agencies

agreed that the small and aging locks on the upper Tennessee River--

Chickamauga, Watts Bar, Fort Loudoun--were constraints to navigation

and that concrete growth at Chickamauga lock threatened its continued

operation. Concrete growth was not a problem at Watts Bar and Fort

Loudoun because of the type of cement and aggregate used to construct

the projects.

The 1988 study examined the feasibility of increasing the existing

locks to 110 x 600 feet size in order to bring the upper Tennessee

navigation locks into conformance with locks below Chickamauga on the

lower Tennessee River. The study concluded, however, that the benefits

would not justify the cost of three new locks on the upper Tennessee

River, and that TVA transportation planners should concentrate on

improvements at Chickamauga and Watts Bar Locks.

The results of the study of lock improvement benefits at

Chickamauga and Watts Bar Dams were presented in a USACE report

entitled Upper Tennessee River Navigation Improvement Study Navigation

System Analysis (1993) which was produced under contract for TVA. The

focus of this study was to estimate benefits that would accrue from a

new 110 x 600 foot lock at Chickamauga which would be constructed

before the existing lock was closed for an 18 month rehabilitation. At

that time, engineering data indicated that the lock could be

rehabilitated to function as an auxiliary lock. The study concluded

that if any capacity constraints occurred at Watts Bar Lock,

nonstructural measures could be used to

[[Page 25728]]

control the situation. TVA will continue to evaluate Watts Bar and Fort

Loudoun projects. However, TVA has no planned upgrades of these

facilities in the foreseeable future.

Because of structural problems and safety concerns TVA continued to

perform engineering analyses of the Chickamauga Lock and Dam using new

methodology referred to as finite element analysis. The finite element

analysis completed in 1995, revealed that because of concrete growth

the lock could not be rehabilitated and that, at best, could function

for another ten years. At some point, the lock would have to be closed

to form a permanent water barrier at the dam. To close the lock, a

concrete plug would be poured into the lock chamber to form a permanent

water barrier.

Extensive structural repairs and maintenance activities to

alleviate problems resulting from concrete continue to be made at

Chickamauga Lock. Instrumentation was installed to monitor structural

movements and internal stresses.

In its evaluation of alternatives to replace the existing lock at

Chickamauga Dam, plugging the lock was defined as TVA's no action

alternative. At this time, the alternative of taking absolutely no

action is not acceptable because of the deteriorating nature of the

lock and potential consequences of dam safety and navigation.

TVA issued a draft EIS on May 10, 1995, that considered the

alternative of continued operation of the existing lock. The final EIS

does not consider the alternative of rehabilitating the lock because of

information described above that became available after release of the

draft EIS.

Alternatives Considered

The following four alternatives were considered by TVA in its final

EIS in attempting to address the structural problems and safety

concerns caused by concrete growth at the Chickamauga Lock.

Alternative 1. Construct a new 110 x 600 foot lock (preferred

alternative).

Alternative 2. Permanently close existing lock (no action

alternative).

Alternative 3. Construct new 60 x 360 foot lock (replacement in-

kind).

Alternative 4. Construct new 75 x 400 foot lock.

The environmental impacts of these alternatives were evaluated in

the final EIS. Because of the structural problems and safety concerns,

all construction alternatives include plugging the existing lock after

the new lock is completed.

Under the no action alternative, the existing lock would have been

plugged and no replacement lock built in its place. This would have

eliminated navigation through Chickamauga Dam. Upstream industries

dependent upon barge transportation would be forced to shift to truck

or rail transport of commodities, and recreational boaters and

commercial tour operator would not be able to move between Chickamauga

and Nickajack Reservoirs. Plugging the existing lock at a cost of $6.8

million to form a permanent water barrier at the dam would have been

the least cost alternative for solving the structural problems at the

lock.

The 110 x 600 foot lock represents the general standard for locks

on the lower Tennessee River and thus, is well suited for barges in

general use today. Lock capacity for the 110 x 600 foot lock has been

rated at 35.7 million tons. Construction of the 110 x 600 foot lock is

estimated to cost $225 million. Total cost of the new lock, including

$6.8 million for closure of the existing lock, is $231.8 million in

1995 dollars. Construction of the 60 x 360 and 75 x 400 foot locks

would have cost $135 million and $160 million respectively.

Basis for the Decision

TVA decided to adopt Alternative 1, that is, construct a new 110 x

600 foot lock, to address the structural problems at Chickamauga Lock

based on environmental, social, economic, recreational, and engineering

and public safety considerations. Alternative 1 was chosen as the

preferred alternative because it would maintain navigation on the upper

Tennessee River and represents the general standard for locks on the

lower Tennessee River and, thus is well suited for barges in general

use today.

Overall benefits include (1) economies related to a more efficient

lock at Chickamauga, (2) a cheaper competitive barge alternative to

overland transportation, and (3) construction of a reliable lock at

Chickamauga.

Among the three lock sizes considered in this EIS, the benefit cost

ratio (4.3) for the 110 x 600 foot lock is higher than the benefit cost

ratio (2.5) for the other two locks. The environmental impacts from the

construction and operation of the smaller 60 x 360 and 75 x 400 foot

locks would be similar to the impacts associated with the preferred 110

x 600 foot lock.

A new 110 x 600 foot lock is expected to generate 467 new jobs and

$16.7 million in new income annually in the Hamilton County area over

its five-year construction period. Of the 467 jobs, 267 would be

directly created while 200 mostly commercial sector positions would be

indirectly created. The $9.8 million directly generated income would

also result in an additional $6.87 million in indirect monetary gain.

While the bulk of these employment and income benefits would accrue to

Hamilton County, the project would also have a positive impact on seven

other counties identified in the project area.

Under alternative 2, plugging the lock would result in the

abandonment of 297 miles of navigable inland waterway and the public's

investment in three navigation locks (Watts Bar, Fort Loudoun, and

Melton Hill) above Chickamauga. The loss of commercial traffic on the

upper Tennessee River is estimated to cost the nation $25 million

annually. Additionally, having a lock in place at Chickamauga Dam

provides shippers in east Tennessee, North Carolina, Virginia, and

South Carolina a competitive alternative to overland transportation

modes and a low cost source of certain commodities. For these reasons,

the no action alternative is unacceptable to TVA.

TVA also considered the use of portage facilities around

Chickamauga Dam to support upstream barge use without the construction

of a new lock. However, because this alternative was not economically

feasible, it was not evaluated in detail.

Construction of a new lock would result in the loss of some

specimen of the endangered pink mucket during dredging for channel

improvements. Other potential adverse environmental impacts from

construction of a new lock can be substantially avoided or minimized

through mitigation measures. By comparison, the no action alternative

of plugging the lock without replacing it would stop navigation between

Chickamauaga and Nickajack reservoirs, isolate the upper from the lower

Tennessee River, and block the potential upstream movement of spawning

migratory species such as sauger and buffalo. TVA has therefore

concluded that there is no clear environmentally preferable alternative

for the Chickamauga Dam--Navigation Lock Project.

Environmental Consequences and Commitments

Environmental consequences associated with construction of a new

110 x 600 foot lock are set out in the final EIS. Environmental impacts

include minor loss of aquatic habitat and resident population of

freshwater mussels, included one listed

[[Page 25729]]

endangered species (pink mucket, Lampsillis orbiculata) These losses

would be mitigated by relocating the mussels and possibly by other

means to be determined during consultation with the United States Fish

and Wildlife Service. Disposal sites would be landscaped and vegetated,

and potential impacts to a federally endangered plant (Mountain

skullcap, Scutellaria montana) located adjacent to a disposal site will

be mitigated through maintenance of a contiguous 250-foot forest buffer

zone. Shoreline restoration downstream will be performed so as to

offset erosion and improve riverine wetlands downstream of the project.

Fugitive dust would be reasonably controlled through periodic wetting

of construction road surfaces or as required by local and state air

regulations. No chemical agents, such as oils, will be used to control

fugitive dust. Construction of a new lock will have an impact on the

existing historic dam complex and will require a Section 106 review. No

potential adverse effects on archaeological or cultural resources are

anticipated. Temporary high noise levels and navigation traffic

congestion would be expected during construction.

Environmental impacts associated with the operation of the new lock

include socioeconomic benefits associated with the continuation of

commercial and recreation lockages and the loss of four spillway bays.

Loss of four spillways bays will not adversely impact TVA's ability to

control flooding up to a 5500 year flood event. Further, through

appropriate design of discharge structures, TVA will attempt to

minimize potential impact on the upstream migration of certain fish

species, such as sauger and buffalo.

The construction and operational environmental impacts for the

smaller 60 x 360 and 75 x 400 foot locks would be similar to the

impacts associated with the proposed 110 x 600 foot lock.

Environmental impacts associated with the no action alternative of

plugging the lock without replacing it, include blocking the potential

upstream movement of spawning migratory fishes, such as sauger and

buffalo. Additionally, navigation through Chickamauga Dam would cease,

causing significant economic impact to industry and recreation and

would isolate the upper Tennessee River from the lower river system for

commercial navigation. This would result in a shift to land transport

of goods shipped through Chickamauga Lock which would have adverse

impact on air quality from increased truck and rail traffic. Further,

separation of the National Oak Ridge Laboratory and other industry from

access to barge transportation could result in lost opportunities for

industrial expansion, and at Oak Ridge, the inability to move certain

national defense equipment there for maintenance and repair.

Additionally, a number of mitigation and monitoring requirements

will be incorporated in construction and operational permits needed for

the Chickamauga Dam--Navigation Lock Project.

Dated: May 13, 1996.

Kathryn J. Jackson,

Senior Vice President, Resource Group.

[FR Doc. 96-12815 Filed 5-21-96; 8:45 am]

BILLING CODE 8120-01-M