Jacksonville District, Jacksonville, FL; Intent To Prepare a Draft Environmental Impact Statement (DEIS) for the C-7, C-8, and C-9 (North Dade) Canals General Reevaluation Report (GRR)

DEPARTMENT OF DEFENSE

Department of the Army

Corps of Engineers

[3710-AJ]

Jacksonville District, Jacksonville, FL; Intent To Prepare a

Draft Environmental Impact Statement (DEIS) for the C-7, C-8, and C-9

(North Dade) Canals General Reevaluation Report (GRR)

AGENCY: U.S. Army Corps of Engineers, Department of Defense.

ACTION: Notice of intent.

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SUMMARY: The Jacksonville District, U.S. Army Corps of Engineers

(Corps), along with the South Florida Water Management District

(SFWMD), intends to prepare a Draft Environmental Impact Statement

(DEIS) for the feasibility phase of the C-7, C-8, and C-9 (North Dade)

Canals General Reevaluation Report (GRR).

FOR FURTHER INFORMATION CONTACT: Questions about the proposed action

and DEIS can be answered by: Mark Ziminske, Planning Division, U.S.

Army Corps of Engineers, P.O. Box 4970, Jacksonville, Florida 32232-

0019; Telephone 904-232-1786/Fax 904-232-3442.

SUPPLEMENTARY INFORMATION:

a. Authorization

Construction of the C-7 (Little River), C-8 (Biscayne), and C-9

(Snake Creek) canals, and associated water control structures, S-27, S-

28, and S-29 was authorized by the Flood Control Act of 1948, which

provided for construction of the first phase of a comprehensive plan

for flood control, fish and wildlife preservation, regional groundwater

control, salinity control, and navigation. The Energy and Water

Development Act of 1955 authorized preparation of a GRR to review

conveyance capacity of existing canals, document the quality of local

maintenance, and to make recommendations for implementable solutions to

flooding problems in the C-7, C-8, and C-9 drainage basins.

b. Study Area

The C-7, C-8, and C-9 basins are located in northeastern Dade

County, Florida; all three canals as well as control structures S-27,

S-28, and S-29 are previously constructed Corps' projects. The C-7

basin comprises 35 square miles, and is approximately 11 miles long.

The western portion of the basin lies in Area B, an area of relatively

poor drainage, west of the coastal ridge, eastern Dade County. S-27 is

a double grated concrete spillway located in C-7,

[[Page 5990]]

which permits release of flood runoff and prevents over-drainage and

saltwater intrusion through C-7.

The C-8 basin comprises about 31 square miles, is approximately 12

miles long, and its western portion is also located in Area B. S-28,

located in C-8, is a double-gated spillway, which permits release of

flood runoff from the C-8 basin and prevents saltwater intrusion

through C-8.

The C-9 basin comprises an area of 98 square miles, 39 square miles

in Dade County and 59 square miles in Broward County. The total canal

length is approximately 11 miles. S-29 and S-30 are control structures

located in the C-9 drainage basin. S-29 is a four-gated spillway which

conveys flood runoff and prevents over-drainage and saltwater intrusion

through C-9. S-30 is a gated concrete culvert which prevents excessive

seepage losses from Water Conservation Area (WCA)-3A by permitting

higher stages in the L-33 borrow canal and supplies water from L-33

borrow canal during dry periods to maintain stages and satisfy

irrigation demands in the C-7, C-8, and C-9 drainage basins. All three

canals discharge into northern Biscayne Bay, at Miami.

c. Project Scope and Preliminary Alternatives

The primary objective of this project is to develop a total

watershed plan which identifies structural and/or operational

modifications to the C-7, C-8, and C-9 canals and the associated water

management facilities. While the project emphasis is to enhance flood

control benefits in the project area, the GRR will also document the

status and quality of maintenance on the existing project and identify

environmental restoration opportunities in conjunction with proposed

project modifications.

Alternatives will be developed and evaluated based on the project

objectives, environmental studies, flood control feasibility, and

economics. Standard Corps' programs HEC-2 and UNET will be used to

develop hydraulic models of the existing and any proposed flood control

features.

In addition to the without project and future conditions, four

preliminary alternatives have been drafted which may be revised pending

model results and public feedback. They include: (1) Modifications to

existing canals to increase conveyance where appropriate and possible;

(2) construction of levees adjacent to existing canals in areas

identified as being susceptible to flooding, possibly in conjunction

with canal cross-section modifications; (3) use of retention storage

basins for peak discharge attenuation, possibly in conjunction with

channel modifications and construction of levees; and (4) operational

changes of existing control structures for the respective canals.

d. Scoping

The scoping process as outlined by the Council on Environmental

Quality will be utilized to involve Federal, State, and local agencies,

affected Indian Tribes, and other interested private organizations and

parties.

A Scoping letter will be sent to interested Federal, State and

local agencies, interested organizations and the public, requesting

their comments and concerns regarding issues they feel should be

addressed in the DEIS. Interested persons and organizations wishing to

participate in the scoping process should contact the U.S. Army Corps

of Engineers at the address above. Significant issues anticipated

include concern for: maintenance of flood protection for the project

area; water quality, particularly in the receiving waters of Biscayne

Bay; wetlands; fish and wildlife; saltwater intrusion into project

canals and the groundwater and; threatened and endangered plant and

animal species. Public meetings will be held over the course of the

study, the exact location, dates, and times will be announced in public

notices and local newspapers.

e. It is estimated that the DEIS will be available to the public

about July 1998.

A.J. Salem,

Chief, Planning Division.

[FR Doc. 96-3383 Filed 2-14-96; 8:45 am]

BILLING CODE 3710-AJ-M