HomeMy WebLinkAboutContract cAc-� 6-a43
CEDAR RIVER MAINTENANCE DREDGING PROJECT MTTIGATION AGREEMENT
The City of Renton(City) and the Washington Department of Fish and Wildlife(Departrnent)
enter into this Mitigation Agreement based upon the mutual promises contained herein,the
consideration for which is hereby acknowledged. The purpose of this agreement is to provide
mitigation for the impacts related to the Cedar River Maintenance Dredge Project as described in
the Project Mitigation Plan and HPA Application No. 4377.
RECITALS
On or about February 20, 2014,the Department received an application for a Hydraulic Project
Approval (HPA; Department application identification (APPS) ID number 4377) from the City
for the proposed Cedaz River Maintenance Dredging Project(the project). On or about May 28,
2015 the application was deemed complete.
On or about November 5, 2015,the Depariment issued a review hold letter, which suspended the
review period pending completion of the Lighting Reduction Plan associated with the project.
The letter also offered that a written mitigation agreement between the Department and the City
would be mutually beneficial and appropriate for the project.
The parties have negotiated an agreement for the project mitigation plan based on the following
terms and conditions:
AGREEMENT
A. HPA to be Issued. The parties hereby agree to incorporate the contents of this agreement
, into the HPA for the project. The Department will issue an HPA in a timely manner
following the execution of this agreement.
B. Proiect Construction. The City will construct the Project substantially per the plans entitled,
"CEDAR RIVER MAINTENANCE DREDGING", dated February 26, 2016. If substantial
changes to the project plans occur prior to issuance of the bid-set plans, the CITY and
DEPARTMENT will coordinate to ensure that a mutually-acceptable final design is
produced.
C. Proiect Timeline. This mitigation agreement continues in effect through the life of the
project(until the HPA for the next maintenance dredging is issued) and does not terminate
upon the expiration of the HPA(APPS ID number 4377).
D. MiNgaHon.The City and Department agree to implement the"Mitigation Plan-Revised
Report Cedar River Maintenance Dredging ProjecY',dated March 1 S,2016 as the basis for
the project mitigation, with the following clarifications.
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1. SpaWIIiIIS III1paCt3. The basis for evaluating the impacts on spawning sockeye salmon
will be continued based on the criteria included in prior HPAs issued for dredging the
lower Cedaz River. Mitigation wilt be considered successful when the total value of the
mitigation provided for impacts on sockeye spawners equals or exceeds an average of 15
percent, as further explained below in Appendix A. Estimation of compliance with
mitigation for impacts on sockeye salmon spawning.
a. All spawner estimates will be based upon"area under the curve"methodology.
b. WDFW and the Muckleshoot Indian Tribe Fisheries Depactment(MITFD)will collect
weekly spawning data in the mainstem Cedar River. The City is allowed to have a
representative participate during the weekly collection of spawning data.
c.The City will collect weekly sockeye spawner counts and redd counts in the two
mitigation channels and will report the results of these counts weekly to WDFW and the
MTTFD.The spawner counts in the two spawning channels(Elliot Channel and Royal
Hills Replacement Spawning Channel)will be coordinated with the weekly spawning
data in the mainstem Cedar River. These spawner counts will be used to evaluate
mitigation success,whereas the redd counts are inforrnational.
d. It is expected, based upon existing data,that the 15 percent minimum average will be
accomplished,provided that the two mitigatian channels are maintained in a fully
functional condition. If the 15 percent minimum average has not been achieved by the
beginning of the sixth year after dredging,the City agrees to develop a contingency plan
and implement alternative mitigation measures to ensure the 15 percent minimum
average is achieved by the 10"'year following dredging,with additional mitigation to
compensate for the cumulative shortfall. If the implementation of alternative mitigation is
delayed,this agreement will be arrtended per section G. The fully functional condition
criteria for the channels shall be based in part on physical criteria and are supplemental to
the 15 percent average criteria.These are described at the end of this agreement in
Appendix B Physical Criteria—Eiliott and Rolling Hills Spawning Channels.
e.The City agrees to monitor in the summer and fall of each year and maintain the
mitigation channels to ensure they meet the physical criteria and to maintain the chartnel
inlets free of debris. Maintenance activities will be initiated within one year of
determining the physical criteria are not being met.
f. If the 15 percent minimum average goal is met or exceeded by the beginning of the
sixth year following dredging, then this mitigation requirement is satisfied and no
additional mitigation is required for spawning impacts,provided the cumulative average
remains at or above 15 percent.
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g. If the 15 percent minimum average is exceeded for the current dredging cycle, any
additional amount will be credited to the City towards mitigation in the next dredging
cycle.
2. Predation Imuacts. The Lighting Reduction Plan(LRP), dated December 11,2015,has
been developed as the primary means of mitigating for predation impacts in the dredged
river reach.
a. Implementation of the LRP shall commence prior to or concurrently with dredging
activities, and it shall be fully implemented on properties owned by the City within
two years of commencing dredging. LRP actions proposed on the Boeing property
shall be fully implemented by the third year after commencement of dredging.
b. A report shall be drafted after the light features are modified as identified in the
implementation plan and will be submitted to WDFW and the MITFD within one
yeaz of completing the lighting modifications and the quantitative assessment noted
below.The report will include
i. A map showing the location of the improved features
ii. A description of the improvement made
iii. A photograph of the feature pre and post improvements
iv. A quantitative assessment of the effectiveness of the plan to reduce
artificial light levels on the dredged reach of the river together with a proposed
plan for further lighting reduction if the assessment shows that the recommended
light levels continue to be exceeded in the impacted reach�f the river.
3. RiAarian Vesetation Impacts. Mitigation for riparian vegetation impacts is described in
the mitigation plan; however,the City and Department agree that the performance of the
vegetation planted for the 1998 dredging was not fully successful, and that more attention
will be given to ensure the success of this mitigation element.
a. For consistency of permitting,monitoring and contingency planning shall occur as
required by the U.S. Army Corps of Engineers permit for the project for a period of 10
years.
b. In addition, the City will develop a long term riparian vegetation maintenance plan for
both the dredged reach and the mitigation side channels for review and approval by the
Department.
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c. In the event that any of the vegetation noted as blocking light in the LRP is removed
for any reason, the City will identify and mitigate other lighting in the lower river to
further reduce light levels in the river.
4. Channel adiustment impacts. A scour monitoring study is described in the project
mitigation plan to be conducted after dredging.This study will include monitoring for scour
upstream of the Renton Library to Houser Way N. and a minimum of one control cross-
section located upstream af I-405. The control cross-section will be used to compare scour at
the control section with the downstream rnonitoring location.
It is not anticipated that scour rates will cause significant head-cutting upstream af the
dredged reach. However, if the post-dredging scour study results indicate scour of 6-inches
or more,throughout the entire reach upstream of the Library to Houser Way N, in excess of
the background scour depths based upon the pre-dredge scour study,then addirianal
mitigation to address this impact will be considered. If a high flow event occurs on the Cedar
River during the monitoring period, the data will be used to determine if the scour that may
occur is due to the high flow event or to the maintenance dredging project.
E. Monitoring and Reaortin�.These shall occur as detailed in the mitigation plan, except as
potentially modified by the Corps pennit or as required by other project permits.
F. Reserved riEhts. The parties reserve all rights to enforce the terms of this mitigation
agreement and the tenns of the HPA.
G.Amendment. The City may request an amendment to this agreement if the mitigation
measures specified above cannot be implemented due to unfareseen circumstances such as delay
in permitting, obtaining land rights,natural disasters,etc. Any amendment shall be subject to
mutual agreement approved by the Department.
H. Termination. The obligation of the City is contingent upon a 4-foot dredge per the plans
entitled,"CEDAR RNER MAINTENANCE DREDGING",dated October 14, 2015,and HPA
Application No. 4377. In the event the dredging depth is reduced from 4-feet to 2-feet,this
agreement will be terminated by giving written norice of tetmination,and the HPA will be
rescinded.
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DATED this day of March ,20I b.
CITY i3F RENTON VV�.SHINGTON DEPARTIvIENT OF FISH
,�NI�WILI3LIFE
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Denis Law Je dahl
Mayor Cc�ntracts and Purchasing Manager
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APPENDIX A. Estimation of Compliance with Mitigation for Impacts on Sockeye Salmon
Spawning.
To calculate the percent mitigation achieved for impacts an sockeye spawning,there are three
components to be added, each expressed as a percentage:
A=spawners downstrearn of library/totai return to Cedaz River. This relates to percent of the
sockeye run spawning in what is considered to be the reach of the river which is directly or
indirectly impacted by the project.The total return includes all spawners, plus any fish removed
for hatchery broodstock at the weir and at Landsburg.
B=the total sockeye spawners in the mitigation channels/total return
C=(B times the number of sockeye removed at the weir)/(total return minus spawners
downstream of the weir). This is to provide a credit for fish collected at the weir which might
otherwise have spawned in the mitigation spawning channels.
Using round numbers for these parameters based upon averages from the available data set, let's
assume,just for illustration:
Total retum to Cedar River= lOQ,000
Spawners downstream of library= 13,000
Spawners downstream of Weir= 13,500
Spawners in mitigation channels=2,000
Number removed at weir=7,000
Therefore:
A= 13,000/100,000= 13 percent
B=2,000/100,000=2.0 percent
C= .Q2 X?,000= 140/(100,000-13,500) =0.2 percent
A+ B+C= 15.2 percent
APPENDIX B. Physical Criteria-Elliot and RvWng Hills Sackeye Spawning Channels
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The following criteria are proposed to supplement the WDFW 1 S%fish usage performance
standard in order to ensure that the channels are maintained in a fully functioning condition and
timely maintenance of these channels is performed as needed.
Criterion#1. Flow depth. Flow depths during the spawning season should range from 0.5 to
1.0 foot throughout the channel during a majority of the spawning season.
Support for this criterion:
1. One foot is the target hydraulic performance for depth for the Elliot channel (Integrated
Aquatics, 2015)as referenced in Appendix E of the Cedar River Maintenance Dredging
Report Mitigation Plan-Revised Report, 14 October 2015, Letter Report to Coast Harbor
Engineering from NW Hydraulic Consultants.
2. Sockeye spawning depth criteria based on Cedar River data were used in the Cedaz River
Instream Flow Incremental Methodology(IFIM) studies. Depths from 0.5 feet to 1.5 feet
were assigned a weighting factor of 1.00 (i.e.,most suitable)in the sockeye spawning
habitat preference curves used in the IFIM rnodeling(see Table VII-7 in the Cedar River
Instream Flow and Salmonid Habitat iltilization Study, Final Report. 1991. Cascades
Environmental Services, Inc. Prepared for Seattle Water Department).
Criterion#2. Water Velocity. Water velocities during the October-December spawning
season should range from 0.7 to 2.3 feet per second along the length and width of the channel.
Support for this criterion:
1. The sockeye spawning velocity criteria used in the Cedar River Instream Flow
Incremental Methodology(IFIM)studies; Velocities from 0.7 ft./s to 2.3 ft./s were
assigned a weighting factor of 1.00(most suitable)in the sockeye spawning habitat
preference curves used in the IFIM modeling(see Table VII-7 in the Cedar River
Instream Flow and Salmonid Habitat Utilization Study, Final Report. 1991. Cascades
Environmental Services, Inc. Prepared for Seattle Water Department).
Criterion #3 a&b. Substrate Quality for Spawning and Incubation (a)The dominant
spawning substrate should consist of inedium gravel to small cobble between 1.5 and 6.0 in .
diameter; and(b) Intra-gravel fine sediment should be<12%less than 0.85 mm diameter.
Monitoring for these criteria should be conducted annually between July 15 and August 31 and
results reported to Corps and WDFW and if required, gravel cleaning or other maintenance
should be performed prior to initiation of the sockeye return period.
Support for these criteria:
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1. Substrate size(a)is based on recommended sockeye spawning substrate data, Table 11 in
Washington Department of Fish and Wildlife and Washington Department of Ecology,
Updated April O5, 2004,Instream flow study guidelines, technical and habitat suitability
issues including fish preference curves.
2. Percent intra-gravel fine sediment(b) of<12%(<0.85mm)is based on the threshold for
properly functioning incubation conditions identified from the literature by the National
Marine Fisheries Service Matrix of Pathways and Indicators(NMFS. 1996. Making ESA
determinations of effect for individual or grouped actions at the watershed scale. National
Marine Fisheries Service,Portlattd, Oregon, USA). This threshold(�12%) was identified
as providing a"good" incubation environment in Washington's Timber Fish and
Wildlife monitoring program(Washington Timber/Fish Wildlife Cooperative Monitoring
Evaluatian and Research Committee, 1993. Watershed Analysis Manual (Version 2.0).
WA Department of Natural Resources).
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