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Trinity River Restoration Program, Weaverville, CA
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: May 5, 2006 (Volume 71, Number 87)]
[Notices]
[Page 26560-26561]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05my06-112]
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DEPARTMENT OF THE INTERIOR
Bureau of Reclamation
Trinity River Restoration Program, Weaverville, CA
AGENCY: Bureau of Reclamation, Interior.
ACTION: Notice and correction regarding implementation of program.
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SUMMARY: On December 19, 2000, the Secretary of the Interior
(Secretary) signed the Record of Decision (ROD) implementing the
Trinity River Restoration Program (Program), which adopted the
Preferred Alternative analyzed in the Trinity River Mainstem Fishery
Restoration Final Environmental Impact Statement (FEIS). The Department
of the Interior (Department) has identified a discrepancy in the
description of the hydrologic forecast used in the annual flow regime
component of the Program. The impacts analysis in the FEIS was based
upon modeling the historic inflows into the Trinity River watershed
above the Trinity Dam and categorizing this data into five water-year
classes. These classes and their probability of occurrence were
displayed in the FEIS and are repeated below:
Table A.--Values from Final EIR/EIS Table 1 (page C-3)
[WY 1912-1995]
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Trinity River Annual runoff
Water-year class allocation (T into Trinity Probability of
AF) Lake (TAF) occurrence
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Critically Dry.................................................. 369 < 650 0.12
Dry............................................................. 453,000 650-1025 0.28
Normal.......................................................... 647,000 1025-1350 0.20
Wet............................................................. 701,000 1350-2000 0.28
Extremely Wet................................................... 815,000 >2000 0.12
Average......................................................... 594
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This discrepancy occurred because the FEIS narrative in Appendix C
incorrectly references use of a 90% exceedence forecast in determining
classes for the upcoming water year. Use of the 50% exceedence forecast
more accurately reflects the occurrence of water year types identified
in the chart above and more closely approximates the impact analysis in
the FEIS.
The corrective action taken by the Department will ensure that any
potential impacts from implementation of the Program are consistent
with the FEIS. This correction does not require any new action or the
modification of an existing action, so no further National
Environmental Policy Act (NEPA) analysis is necessary. Moreover,
correcting this error in the FEIS Appendix C narrative will have no new
impacts on the goals of the Program, or on water and power users beyond
what has already been disclosed and analyzed in the FEIS, and there is
no change in the ROD itself. By making this correction now,
Reclamation's actions with regards to determining the water year type
for the 2006 water year will be consistent with the impacts analysis
approved in Westlands Water District v. Department of the Interior 366
F.3d 853 (9th Cir, 2004). In summation, the NEPA and Trinity River Flow
Evaluation Study (TRFES) analysis are unchanged and Reclamation is
simply ensuring that implementation of the Program reflects the
analyses used in the FEIS and ROD.
DATES: The Secretary is not proposing to take any new action as a
result of this Federal Register notice. Accordingly, the Department is
not establishing a specific date by which comments must be submitted.
ADDRESSES: You may submit written comments to Douglas Schleusner,
Executive Director, Trinity River Restoration Program, P.O. Box 1300,
[[Page 26561]]
1313 South Main Street, Weaverville, California 96093.
FOR FURTHER INFORMATION CONTACT: Douglas Schleusner at (530) 623-1800.
SUPPLEMENTARY INFORMATION: On December 19, 2000, the Secretary, with
concurrence of the Hoopa Valley Tribe, signed the ROD for the Program.
The decision outlined in the ROD called for the implementation of the
Preferred Alternative, which incorporated the recommendations developed
in the TRFES and evaluated in the FEIS under the Flow Evaluation
Alternative, coupled with additional watershed protection efforts
identified in the Mechanical Restoration Alternative contained in the FEIS.
A component of the Flow Evaluation Alternative is a flow regime
that is intended to achieve various anadromous fishery habitat
objectives associated with meeting the goals of the Program. The
recommended flow regime and the water year class, which determine the
volume of water available in a given year, were developed from historic
annual hydrologic records of the Trinity River watershed. Under the
ROD, the water year class for any given year is determined based on the
total water runoff (unimpeded flow) forecasted to occur in the Trinity
River watershed above Trinity dam, as of April 1 of each year. The
water year classes and expected probability of occurrence are stated in
the chart above.
Appendix C of the FEIS sets out the process for the water year
class forecast. On page C-4 the FEIS states: ``Annual basin runoff is
calculated by summing the amount of runoff that has occurred form
October 1 until April 1 and a volume of water that Reclamation
forecasters predict (90 percent probability of exceedence) will run off
during the months remaining in the water year (i.e. April through
September) using the April 1 runoff forecast projection from the
California Cooperative Snow surveys, California Department of Water
Resources, Bulletin 120. Total water runoff is then compared to the
ranges in Table 1 [of Appendix C]
to designate the water year class.''
In fact, the 50% exceedence value enables a substantially more
accurate forecast of a water year class than the 90% exceedence value.
Program staff have determined that use of the 90% exceedence criterion
would under-predict (i.e. predict a drier year than actually occurred)
the actual water year class in 18 of the 49 years from which the
necessary records were available to conduct the analysis. Of the 18
years, 8 years had later rain events in May or June.
The results of such under-prediction would negatively affect the
successful implementation of the Program. The identification and
evaluation of impacts associated with the alternatives evaluated in the
FEIS were based on the historic hydrology of the Trinity River, and how
that water was allocated between diversions to the Central Valley
Project and flows down the Trinity River. The modeling of impacts
associated with each alternative, especially with regard to impacts to
water supply delivery and hydropower generation by the CVP for any
given year class, was based upon what actually happened in that water
year class historically, not upon what an April 1 forecast using a 90
percent exceedence criterion would have been.
As documented in the Final Report on the TRFES and in the FEIS, the
majority of the geomorphic work to restore and maintain anadromous
fishery habitat in the mainstem of the Trinity River is expected to
occur during ``wet'' and ``extremely wet'' years. Continued use of the
90 percent exceedence criterion would result in a failure to experience
the number of wet years anticipated by the ROD over the extended
implementation of the Program, which would jeopardize the success of
the Program.
Reclamation is correcting the reference to the April 1 exceedence
criterion from 90 percent to 50 percent, based upon investigations by
Program staff, with input from the Hoopa Valley Tribe and the Trinity
Adaptive Management Working Group (TAMWG). Program staff determined
that use of the 50 percent criterion would correctly predict 44 of 49
of the years for which the necessary records were available.
Additionally, of the remaining years, three resulted in underestimating
the year class and two resulted in overestimating the year class. The
resultant accuracy rate when using the 50 percent exceedence criterion
is approximately 90 percent when compared to the historic record, with
the errors almost balanced in over and under predicting the water year
class. Thus the 50 percent exceedence criterion is approximately 90
percent accurate while the 90 percent exceedence criterion success rate
is only slightly above 63 percent, with the errors consistently
resulting in a prediction that is drier than that which ultimately
occurs. This correction will not affect the decision adopted in the ROD
or the supporting environmental analysis in the FEIS.
The Department hereby corrects the process by which the water year
class is identified in the FEIS for the Trinity River Mainstem Fishery
Restoration Program in order to implement the alternative selected in
the ROD for the Program. The correction replaces the 90 percent
exceedence criterion used by Reclamation to forecast runoff in the
Trinity River watershed as of April 1 of each year, with a 50 percent
exceedence criterion.
Submitting Comments
The Secretary is not proposing to take any new action as a result
of this Federal Register notice. Accordingly, while the Department
welcomes comments, the Department is not establishing a specific date
by which comments must be submitted. Public comments on other aspects
of this Adaptive Environmental Assessment and Management (AEAM) program
may always be submitted to the TMC, the TAMWG, or the Executive Director.
Our practice is to make comments, including names and home
addresses of respondents, available for public review. Individual
respondents may request that we withhold their home address from public
disclosure, which we will honor to the extent allowable by law. There
also may be circumstances in which we would withhold a respondent's
identity from public disclosure, as allowable by law. If you wish us to
withhold your name and/or address, you must state this prominently at
the beginning of your comment. We will make all submissions from
organizations or businesses, and from individuals identifying
themselves as representatives or officials of organizations or
businesses, available for public disclosure in their entirety.
Frank Michny,
Regional Environmental Officer, Mid-Pacific Region.
[FR Doc. E6-6794 Filed 5-4-06; 8:45 am]
BILLING CODE 4310-MN-P