[Federal Register Volume 64, Number 121 (Thursday, June 24, 1999)]
[Notices]
[Pages 33848-33851]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-16145]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF DEFENSE
Department of the Army, Corps of Engineers
Intent To Prepare an Environmental Impact Statement/Report/
Feasibility Study for the White Slough Flood Control Study, City of
Vallejo, Solano County, CA
AGENCY: U.S. Army Corps of Engineers, DoD.
ACTION: Notice of intent.
-----------------------------------------------------------------------
SUMMARY: The purpose of the feasibility study is to identify and
evaluate alternatives which will lead to flood protection for areas
adjacent to White Slough, south of Highway 37 in Vallejo. To fulfill
the requirements of Section 102(2)(c) of the National Environmental
Policy Act, the Corps of Engineers has determined that the proposed
action may have significant effect on the quality of the human
environment and
[[Page 33849]]
therefore requires the preparation of an Environmental Impact
Statement. This document will also serve as the Environmental Impact
Report (EIR) under the California Environmental Quality Act (CEQA).
Lead Agency under CEQA is the Vallejo Sanitation and Flood Control
District. This environmental assessment is required by the National
Environmental Policy Act of 1969, as amended (PL 91-190). Section
102(2)(A) requires Federal agencies to: ``Utilize a systematic
interdisciplinary approach which will insure the integrated use of the
natural and social sciences and the environmental design arts in
planning and decision making which may have an impact on man's
environment.''
FOR FURTHER INFORMATION CONTACT: Written comments and questions
regarding the scoping process or preparation of the EIS/EIR/FS may be
directed to Craig Vassel, U.S. Army Corps of Engineers, San Francisco
District, 333 Market Street, 717P, Seventh Floor, San Francisco, CA
94105-2197, (415) 977-8546, Fax: 415-977-8695, Email:
cvassel@smtp.spd.usace.army.mil.
SUPPLEMENTARY INFORMATION:
1. Authority
Pursuant to Section 102(2)(c) of the National Environmental Policy
Act (NEPA) of 1969 as implemented by the Council on Environmental
Quality regulations (40 CFR Parts 1500-1508), the California
Environmental Quality Act (CEQA), the Department of the Army and
Vallejo Sanitation and Flood Control District hereby give notice of
intent to prepare a joint Environmental Impact Statement/Environmental
Impact Report/Feasibility Study (EIS/EIR/FS) for the White Slough Flood
Control Project, Solano County, California.
2. Comments/ Scoping Meetings
Interested parties are requested to express their views concerning
the proposed activity. The public is encouraged to provide written
comments in addition to or in lieu of, oral comments at the scoping
meeting. To be most helpful, scoping comments should clearly describe
specific environmental topics or issues, which the commentator believes
the document, should address. Oral and written comments receive equal
consideration. Two workshop-scoping sessions will be held on Wednesday
July 7, 1999. The first 2:30-4:30 is intended primarily for local,
state, and federal agencies and organizations. The second 7:00-9:00 is
intended for all interested parties. Both meetings will be at the
offices of the Vallejo Sanitation and Flood Control District Offices,
450 Ryder Avenue, Vallejo, CA.
3. Availability of EIS/EIR/FS
The Draft EIS/EIR/FS should be available for public review in Fall
1999.
4. Agencies Supporting Project.
The U.S. Army Corps of Engineers and Vallejo Sanitation and Flood
Control District will be the lead agencies in preparing the combined
EIS/EIR/FS. The EIS/EIR/FS will provide an analysis supporting both the
requirements of NEPA and CEQA in addressing impacts to the environment
which may result from implementation of flood control measures.
5. Purpose and Need for Project:
This project is intended to reduce the risk of flooding from all
sources in the vicinity of White Slough, south of Highway 37 in
Vallejo.
6. Study Area Description
White Slough is bisected by Highway 37. The southern portion, south
of Highway 37 which is part of the Slough or subject and flooding is
the study area for this project.
7. Levee Construction History
a. Located between the Napa River and the City of Vallejo, White
Slough receives both tidal flow from the Napa River and fluvial flow
from Chabot and Austin Creeks. Around 1900, local interests constructed
a levee along the east bank of the Napa River, which allowed for the
reclamation of approximately 816 acres of wetlands adjacent to White
Slough; 604 acres west of Highway 37 and 212 acres southeast of Highway
37.
b. After floods breached these levees in 1964 and 1969, the Corps
of Engineers subsequently repaired them. The 1969 repairs were
performed under the authority of Public Law 81-875, which requires that
local interests maintain the repaired levees. Floods again breached the
levees in the winters of 1976, 1977, and 1978. This time, since
inspections indicated that little or no levee maintenance had been done
by local interests since they were last repaired in 1969, the Corps of
Engineers had no authority to repair the levees. The land owners of
property protected by the levees refused to make repairs without a
guarantee that they could develop their land. During this period, the
Bay Conservation and Development Commission (BCDC) claimed jurisdiction
over the White Slough area. Little activity has occurred within the
White Slough area in the intervening years.
8. Austin Creek
Austin Creek flows in an unlined channel along the southern
perimeter of White Slough. Flow in this channel is carried by three
road culverts. Because Austin Creek is separated from White Slough by a
low levee (six feet NGVD), it can only be drained by the Austin Creek
Pump Station.
9. 1983 Tidal Flooding
In 1983, a tide in excess of the 100-year event, combined with
storm runoff, caused extensive flooding in the vicinity of White
Slough. The Austin Creek Channel levee was overtopped, and flooding
occurred on Sacramento Street, Sonoma Boulevard, and in the Larwin
Plaza and K-Mart areas. After this event, the Austin Creek levee was
raised by about three feet on the outboard side to protect the
Sacramento Street area against tidal flooding. Today, the only tidal
flooding protection in the White Slough area is provided by an
emergency levee along the northern side of Highway 37, constructed by
the City of Vallejo.
10. Fluvial Flooding Problem
Austin Creek's overtopping is the primary cause of fluvial
flooding. The Austin Creek Pump Station provides adequate outlet
capacity for three to five year fluvial flood events, but the channel
and road crossing culverts do not convey flow to the pumps fast enough.
During past flood events, the pump station pumped the immediate
upstream channel reach nearly dry, while water was still ponding to
significant depths behind the Redwood Street and Valle Vista Street
culverts. Backwater conditions and obstruction by debris greatly reduce
the capacities of the bridge culverts at Redwood Street and Valle Vista
Avenue. The 100-year design flow of 1583 cfs significantly exceeds
channel and culvert capacities regardless of backwater conditions.
11. Highway 37 Project
Caltrans' will use fill to raise and widen the highway and install
additional culverts with tide gates under Highway 37. This will provide
limited tidal exchange and tidal flood protection to the highway and
the study area south of the highway subject to tidal flooding.
12. Project Alternatives
a. No action. This alternative assumes that no flood control
project, structural or non-structural, other than the Highway 37
project, will be
[[Page 33850]]
implemented in the project area by the federal government or any other
entity. Flooding would continue at the same frequency and intensity as
it has in the past. Tidal flooding would be controlled by the Caltrans
Highway 37 project. Inadequately protected areas around White Slough
would continue to risk flood damage.
b. Flood Control Alternatives. Preliminary flood damage reduction
alternatives studied for the White Slough and Austin Creek areas fall
into two categories: Tidal and fluvial.
13. Tidal Flood Protection From Highway 37
Tidal flood protection to the highway and to those portions of the
study area south of the highway subject to tidal flooding will be
provided by Caltrans' Highway 37 improvement project. The project
includes using fill to raise and widen Highway 37. Four additional 48-
inch diameter culverts with tide gates under Highway 37 will limit
tidal exchange to provide tidal flood protection. Levee protection
would be required in areas where the existing tidal barrier falls below
the 100-year tidal flood event.
14. Fluvial Alternatives.
Several alternatives to control fluvial flooding will be
considered:
a. Retention ponds. Two retention ponds, each 10 feet deep, would
be constructed on vacant land adjacent to Austin Creek just west of
Sonoma Boulevard, creating a total of 60 acre-feet of storage upstream
of Valle Vista Avenue. Storage of floodwater does not occur naturally
at this site; therefore, any storage would have to be developed through
excavation of native material and artificial fill on the property. Flow
diverted into the basins would then drain by gravity back into the
channel at a slower rate.
b. Bridge improvements. To decrease backwater conditions caused by
obstructions; thereby increasing the capacity of Austin Creek, bridge
improvements are being considered as well as removal of the abandoned
culvert structure between Redwood Street and Highway 37. New pipes
could be added to existing culvert bridge structures at Redwood Street
and Valle Vista Avenue, or the existing culvert structures replaced
with larger box culverts or clear span bridges.
c. Pump station improvements. The pump station at Austin Creek is
limited in capacity. Any alternative which increases the capacity of
Austin Creek could require an upgrading of the Austin Creek Pump
Station, or a diversion of Austin Creek storm flow to a storage
facility, such as White Slough, for retention.
d. Austin Creek flow diversion. If excess flows in Austin Creek
above the Redwood Street and Valle Vista Avenue bridges are diverted,
this could eliminate or reduce the need to upgrade the bridges. To
divert these flows, a 2400-foot parallel pipe system would carry flows
from the basin above Austin Creek directly into White Slough a clear
passage of flow from Austin Creek into White Slough by removal of the
levee system along the eastern bank of Austin Creek between Redwood
Street and Highway 37, or directly into Austin Creek below Valle Vista
Avenue or Redwood Street. This diversion structure could be combined
with creation of a confluence between Austin Creek and White Slough. If
White Slough received excess flows from Austin Creek during high flow
periods, the existing Austin Creek Pump Station could then drain White
Slough. The best location for such a confluence appears to be along the
levee that separates Austin Creek from White Slough. Controllable gates
could be installed within the barrier separating Austin Creek from
White Slough.
e. Austin Creek Creekside protection. Levees or floodwalls by
themselves or in combination with other improvement options may also be
used to increase the capacity of the Austin Creek channel. This
alternative does not address the causes of flooding, but merely
contains the flow within Austin Creek.
f. Removal of levees/restore confluence of Austin Creek and White
Slough. 1000 lineal feet of levee along the east bank and 1000 lineal
feet of floodwalls on the west bank of Austin Creek between Redwood
Street and Valle Vista and 1500 lineal feet of floodwalls on both banks
of Austin Creek extending from Valle Vista Avenue to the upstream?would
create a clear passage of flow in Austin Creek from Redwood Street to
Highway 37.
g. Perimeter flood protection. 2000 lineal feet of floodwall and
2500 feet of levee along the perimeter of White Slough south of Highway
37, 1000 lineal feet of levee along the east bank and 1000 lineal feet
of floodwalls on the west bank of Austin Creek between Redwood Street,
and Valle Vista and 1000 lineal feet of floodwalls on both banks of
Austin Creek extending from Valle Vista Avenue to the downstream limit
of the retention ponds would be constructed.
15. Feasibility Study
The five-phase Feasibility Study will identify and evaluate
measures to restore lost tidal prism and reduce the rate of
sedimentation as follows:
a. Phase One will investigate existing physical and environmental
conditions restoration needs and constraints of the area. The future
without-project conditions in the study area will be projected. Input
on the ecosystem will be sought from resource agencies and the public.
Public scoping workshops will be held both in Vallejo.
b. During Phase Two, hydraulic modeling of the preliminary
alternatives will be completed and economics and environmental impacts
studied.
c. In Phase Three, preliminary alternatives will be evaluated and
benefits of the alternatives will be quantified. A draft Fish and
Wildlife Coordination Act Report possibly including a Habitat
Evaluation Procedure (HEP) will be prepared to help provide the basis
for identifying the most cost-effective alternative acceptable to the
agencies and community.
d. Phase Four involves preparing the draft Feasibility Report and
Environmental Impact Statement/Report (EIS/R). The EIS/R will analyze
all reasonable alternatives and evaluate compliance with federal and
state environmental requirements. A formal public review and comment
period will be started.
e. The last phase of the study includes preparing the final
Feasibility Report recommending a preferred alternative and completing
the final EIS/R which will respond to all comments on the draft EIS/R.
16. Other Environmental Review and Consultation Requirements
The DEIS/R will be used as the primary information document to
secure concurrence in a Federal Coastal Zone Consistency Determination
to comply with Clean Water Act Section 404 (b) (1) guidelines, the Fish
and Wildlife Coordination Act, and the Endangered Species Act. The
DEIS/R will be used by the local sponsor to meet its responsibilities
under the California Environmental Quality Act, and used by the San
Francisco Regional Water Quality Control Board to meet its
responsibilities under the Porter-Cologne Act. The DEIS/R will be used
for ``trustee agency'' reviews by the State of California.
[[Page 33851]]
17. DEIS Availability
The DEIS will be available to the public in Fall 1999.
Peter T. Grass,
LTC, EN, Commanding.
[FR Doc. 99-16145 Filed 6-23-99; 8:45 am]
BILLING CODE 3710-19-P
