Los Angeles 33 Department of Water & Power

ERIC CiARCETTIMayor

January 28, 2016

Commission

MEL LEVINE, PresidentWILLIAM W. FUNDERBURK JR., Vice PresidentJILL BANKS BARAD

MICHAEL F. FLEMING

CHRISTINA E. NOONAN

BARBARA E. MOSCHOS, Secretary

MARCIE L. EDWARDSGeneralManager

Dr. Robert Harrington, DirectorInyo County Water DepartmentP.O. Box 337

Independence, CA 93526-0337

Dear Dr. Harrington:

Subject: Draft 2016 Five Bridges Mitigation Plan

Enclosed is the Draft 2016 Five Bridges Mitigation Plan for your consideration. The LosAngeles Department of Water and Power (LADWP) looks forward to working with InyoCounty Water Department Staff to finalize a mitigation plan for the Five Bridges area. Asyou are aware, LADWP has regularly conducted mitigation efforts in this area (includingsupplying water annually, weed control, and vegetation monitoring) since the originalimpact in 1989. However, as our staffs have discussed, these efforts can be improvedupon to more efficiently use water and more effectively reach mitigation goals.

Please contact Ms. Lori Dermody, Watershed Resources Supervisor, to discuss furtheror to set up a meeting. She may be reached at 760-873-0408 or atlori.dermodv(a)ladwp.com.

Sincerely,

Jarries G. YannottaManager of Aqueduct

LD.fj

Enclosurec: Ms. Lori S. Dermody

Los Angeles Aqueduct Centennial Celebrating 100 Years of Water 1913-2013Bishop. California mailing address: 300 Mandich Street • Bishop. CA93514-3449 • Telephone: (760)873-0208 • Fax:(760)873-0266

111 North Hope Street. Los Angeles. CA 90012-2607 Mailing address: Box 51111, Los Angeles. CA 90051 -5700Telephone: (213) 367-4211 www.LADWP.com

2016 Five Bridges Mitigation Plan

(For Compliance with the City of Los Angeles Department of Water and Power and County of Inyo's1991 Final Environmental Impact Report on

Water from the Owens Valley to Supply the Second Los Angeles Aqueduct, 1970 to 1990,1990 Onward, Pursuant to a Long Term Groundwater Management Plan)

Inyo County/Los Angeles Technical Group(January 2016)

2016 Five Bridges Mitigation Plan

1.0 Introduction

1.1 Management of Five Bridges Mitigation Area, 1991-2015

2.0 2016 Five Bridges Mitigation Plan2.1 Flow Management2.2 Land Management

2.2.1 Native Revegetation Efforts2.2.2 Grazing Management2.2.3 Recreation Management

2.2.4 Weed Management

3.0 Implementation Schedule

4.0 Monitoring

5.0 Reporting

6.0 References

1.0 Introduction

The Los Angeles Department of Water and Power(LADWP) is responsible for mitigating impactstonative vegetation in the Five Bridgesarea per Impact and Mitigation Measures 10-12 in the 1991 FinalEnvironmental Impact Report on Water from the Owens Valley to Supplythe Second Los AngelesAqueduct, 1970 to 1990,1990 Onward, Pursuant to a Long Term Groundwater Management Plan(LADWP and County of Inyo 1991a, hereinafter referred to as 1991 EIR). These items read:

Impact 10-12

"Vegetation in an area ofapproximately 300 acres near Five BridgesRoad north ofBishop was significantlyadversely affected during 1988 because of operation of twowells to supply water to enhancement/mitigation projects/'

Mitigation Measure 10-12

"Water has been spread over the affected area since 1988. By the summer of 1990,revegetation of native species had begun on approximately 80 percent of the affectedarea. LADWP and Inyo County are developing a plan to revegetate the entire affectedareas with riparian and meadow vegetation. Thisplan will be implemented when it hasbeen completed."

Since 1991, LADWP has implemented various efforts to recover native vegetation in the mitigation areathrough re-irrigating the affected area each growing season, extensive weed treatment to eradicateperennial pepperweed [Lepidium latifolium), and development and implementation of a grazingmanagement plan to compliment these efforts. LADWP has also used controlled burns, sprinklerirrigation, seeding banks and outplanting native species to assist in mitigating the original impacts.

Conditions in the Five Bridges mitigation area have varied over the years. Mitigation Measure 10-12states that approximately 80% of the impacted area was mitigated at the time the FEIR was adopted.Further, the Mitigation Monitoring Program that accompanied the FEIR states that the mitigationproject was 90% completed at that time (LADWP and Inyo County 1991b). In recent years, there havebeen declines in native vegetation collectively due to consecutive drought years, invasion of perennialpepperweed, and subsequent weed treatment efforts to eradicate this invasive species.

1.1 Management of Five Bridges Mitigation Area, 1991-2015

Mitigation efforts implemented to date have been a product of LADWP and Inyo County's collaborationwith the Five Bridges subgroup in the early 1990s, professional expertise from outside consultants, andvarious plans developed (but not approved) by the Inyo/Los Angeles Technical Group in the late 1990sand early 2000s. Under the 1997 MOU between LADWP, Inyo County, and various entities that providedresolution to outstanding issues with the 1991 EIR, the Inyo/Los Angeles Technical Group is charged withpreparing mitigation plans and implementation schedules for all areas which onsite mitigation measureshave been adopted in the 1991 EIR. Consequently, the Technical Group jointly worked on the 1999Revegetation Plan for Impacts Identified in the LADWP, Inyo County EIR for Groundwater Management(Mitigation Plan) upon discharge of the writ. This plan was never officially adopted by the TechnicalGroup according to City and County records, yet many elements of this Mitigation Plan have beenfollowed since its development.

In the 1999 Mitigation Plan, irrigation to the Five Bridges mitigation project was to be supplied throughplanned high flows in the Owens River (660 cfs+) that would flood the area three times during thegrowing season to facilitate natural recovery. Annual photopoint and permanent vegetation transectmonitoring were also prescribed in the 1999 Mitigation Plan.

LADWP attempted to implement irrigation flows as specified in the Mitigation Plan, however high riverflows were no longer feasible in the Owens River system due to reductions in exports from the MonoBasin. Consequently, LADWP began regularly supplying the three described flows by releasing waterthrough the Bishop Creek Canal (Diversion 2) into the west side of the project area to points A, B, and Cshown on Figure 1. Formal recognition of the modified water source for the project was also neveradopted by the Technical Group but was a reliable source of water for the mitigation project. LADWPhas provided flows through the project three times per year from the alternate source through 2014. In2015 due to drought, water shortages in the City's water supply, and LADWP's attempt to provide allirrigation and in valley uses in Inyo County, LADWPcould not supply the three mitigation flows to theproject area within the growing season. However, LADWPcontinued weed treatments at Five Bridgesand explored options to improve water spreading efficiency in the mitigation area. Following irrigationseason, LADWP released one mitigation flow to the Five Bridges area in October and November 2015equivalent to all three flows in an average year to provide recharge to the mitigation area.

All monitoring described in the 1999 Mitigation Plan has been conducted annually and includes annualphotopoint and permanent vegetation transect monitoring (See L4Aand L4B on Figure 1). Whilevegetation in the West Meadow (L4B) was nearing recovery a few years ago, LADWP has noted declinesat both permanent transects in recent years. These vegetation declines are likely due to successive dryyears, extensive pepperweed invasion and subsequent weed treatment, as herbicides have alsoimpacted native species though focused on exotics. Additionally, LADWP has monitored a rare planttrend plot for Owens Valley Checkerbloom {Sidalceacovillei) annually since 1993. It has shown anoverall downward trend throughout the mitigation period, although a sharper decline since 2009. It issuspected that the rare plant population was impacted from herbicide treatment that year and has notrecovered.

Continual limitations and challenges of this project include:• substantial weed infestation by perennial pepperweed throughout the project area and

subsequent treatment using significant application of herbicide that has also impacted nativemeadow species;

• drought/continual dry years,• and poor distribution of flows to alkali meadow areas in need of recovery.

LADWP and Inyo County Water Department (ICWD) both recognize a need to improve/revise currentmitigation efforts at Five Bridges in order to meet mitigation goals. LADWP and ICWD Staff met in thefield to discuss current practices and preliminary changes to this project in April 2015. This updated planis intended to build on knowledge and experience gained from previous efforts in mitigating the areawhile also incorporating new ideas from LADWP and ICWD's professional staff. The plan uses acombination of flow and land management approaches to recover the mitigation area to native meadowand riparian communities, taking into consideration operational limitations and current environmentaland climatic conditions.

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formany years. However, previous flows have been limitedto a series of ditches in the projectarea,some of which are severely downcut and therefore isolate the flows' benefits to existing channels. In anattempt to geographically expand the benefit of the mitigation flows, LADWP will install a series ofwooden diversion structures throughout the mitigation areato improve efficiency of water spreadingbydirecting it to areas that have not been irrigated for some time due to channelization. These proposedlocations are shown in Figure 2 below.

Additionally, LADWP will replace culverts under the road abutting the east side of the main mitigationarea and install Waterman Gates on the west side of these culverts to control flows (Figure 2). This willenable irrigators to block flow at these locations when necessary, consequently backing up water intothe mitigation area to optimize the spread of water.

Flows will be timed such that a large release will occur in early spring to jumpstart the growing season.This early pulse will vary annually based on the spring thaw. 1-2 additional flows will be releasedthroughout the growing season based on vegetation needs and operational flexibility in supplying therelease from the Bishop Creek Canal. LADWP and its ranch lessee will manage flows adaptively to suitvariable annual conditions and to target areas with the most need of recovery. Consequently, flows maynot reach the same endpoints with each release as they have in past years. In doing so, water will bedirected to areas of low vegetative cover or that are otherwise in need of recovery. Volume of flowssupplied to the project will be consistent with that provided in previous years.

Action Required:1. File CEQA exemption for installation of new wooden check structures and Waterman gates for

flow management in mitigation area (minor alteration to land)2. Installation of new check structures and Waterman gates in mitigation area and replacement of

culverts

3. Release flows annually into mitigation area at optimal times for native species establishmentand persistence (early spring and 1-2 times throughout growing season)

4. Manage flows adaptively to spread water to areas in need of recovery

Figure 2. Five Bridges Proposed Water Diversions

2.2 Land Management

2.2.1 Native Revegetation Efforts

Seeding and outplanting native plants in the mitigation area have been tried numerous times. Althoughnative vegetation appears to have declined in recent years, it is likely that there is a seed source ofnative species onsite that may flourish with more efficient water spreading in the area. In addition,LADWP will broadcast additional native seed in the mitigation area during spring of 2016 to help assistwith recruitment. These native species will include, but will not be limited to: alkali sacaton {Sporobolusairoides), saltgrass {Distichlic spicata), creeping wildrye {Leymus triticoides), rubber rabbitbrush{Ericameria nauseosus), wiregrass {Juncus balticus), and bulrush [Schoenoplectus sp.) Seedingwill occurfor each of these species based on the optimal time for germination.

Action Required:

1. Broadcast native seed in portions of the mitigation area with low cover in spring 2016

2.2.2 Grazing Management

The Grazing Management Plan for the Reinhackle Ranch Grazing Lease (RLI-492) that includes the FiveBridges Mitigation Area was adopted as part of LADWP's Owens Valley Land Management Plan (OVLMP)in 2010. This plan allows for winter/spring grazing across the lease from November 1- June 1 annually.Specifically with regard to the Five Bridges mitigation area, cows can graze the North Restricted, SouthRestricted, and North Five Bridges Fields using a three-pasture double rest rotation (Figure 3). As aresult, each of these fields will be grazed only once every third year. The Multiple Completion MeadowPasture will continue to be excluded from all livestock grazing until ongoing restoration activities arecompleted. For the complete Reinhackle Ranch Grazing Management Plan, please refer to the FinalOVLMP (LADWP 2010).

Additionally, LADWP will establish utilization transects and place cages in the North Restricted andNorth Five Bridges Riparian Pastures and incorporate a 40% riparian utilization standard into the existinggrazing plan. These utilization transects will be monitored annually and data will be used by LADWP toguide management and control grazing pressure on the lease and in the mitigation area.

Action Required:

1. Establish utilization transects and place cages in riparian pastures to guide grazing management

2. Continue to rest the Multiple Completion Meadow from grazing until restoration activities arecomplete

3. Monitor grazing utilization annually

Figure 3. Reinhackle Ranch Grazing Lease, RLI-492

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2.2.3 Recreation Management

The mitigation area is currently accessible to the public. The Powder River Gate on the east side of themitigation area is locked; however, the public can access the mitigation area from the west side.Conditions of the roads in the area are deteriorating. Recent off-highway vehicle use has been notedand is not suspected to solely be the footprint of weed treatment efforts. As a result, LADWP will lockgates to public access on both the west and east ends of the mitigation area, and post signs indicatingthat the area is a restoration site and closed to OHV use.

Action Required:1. Lock Powder River Gate on southwest side of mitigation area2. Post signs near access points indicating that it is a restoration area and that recreational OHV

use is prohibited

2.2.4 Weed ManagementWeed management efforts will continue in the mitigation area as has been conducted in the pastincluding application of broadleaf specific herbicides. LADWP will continue to explore the efficacy ofadditional treatment methods, products, and variable timing and degree of application to combatperennial pepperweed. Recognizing that soil condition in the mitigation area is likely compromised fromcontinual application of herbicides, LADWP will conduct a soil fertility test in the mitigation area toidentify nutrient deficiencies. This information will be used to generate an effective weed eradicationprogram that is geared specifically to this area if current methods can be improved upon.

Action Required:1. Continue current weed eradication efforts for perennial pepperweed2. Conduct literature review and consultation with professionals on effective weed eradication

programs for perennial pepperweed3. Conduct soil fertility study in the Five Bridges Mitigation area to identify possible nutrient

deficiencies

4. Modify current weed eradication program through adaptive management if supported by newinformation

3.0 Implementation Schedule

This Plan provides a 3 year implementation schedule and requires reassessment following reporting inSpring 2019. This approach provides the opportunity to evaluate short term mitigation progress andidentify the need, if any, for change in direction with management efforts in 3 years.

LADWP will initiate the initial seeding effort in spring 2016. LADWP will complete CEQA documentationneeded for installation of new diversion structures and Waterman gates, and culvert replacementsduring the winter of 2015-2016. If feasible, these structures will be installed prior to spring 2016 waterreleases. Utilization transects will be established in 2016 for the 2016-2017 winter grazing season.Weed management research and studies will be conducted in 2016. See Table 1 for full schedule ofimplementation activities

Table 1. 2016 Five Bridges Mitigation Plan Implementation Schedule

Mitigation Action

Winter

2015-

2016

Spring

2016

Summer

2016

Fall

2016

Winter

2016-

2017

Spring

2017

Summer

2017

Fall

2017

Winter

2017-

2018

Spring

2018

Summer

2018

Fall

2018

Winter

2018-

2019

Spring

2019

Flow Management

CEQA for installation of diversion

structures, Waterman Gates, and

culvert replacement on ditches X X

Installation of diversion

structures, Waterman Gates, and

culvert replacement X X

Spring Mitigation Flow

(average and above average

water years) X X X X

Growing Season Mitigation Flow

(1-2) (average and above average

water years) X X X

Land Management

Seed low cover areas with native

species X

Establish utilization transects X

Lock gates/Limit Public Access X X

Post Restoration signs X

Weed Eradication Efforts X X X X X X X X X

Weed Eradication Research X X

Soil Fertility Study X X

Monitoring

Photo Point Monitoring X X X

Vegetation Transect Monitoring X X X

Rare PlantTrend Plot Monitoring X X X X

Grazing Utilization Monitoring X X X X X X

Reporting

Reporting in LADWP Annual

Owens Valley Report X X X X

Final Reporting/ Evaluation by

Technical Group X

Adaptive Management As necessary

4.0 MonitoringUnder this Plan, LADWP will continue to conduct annual photo point monitoring and permanentvegetation transect monitoring at the peak of the growing season. Locations of these transects andphoto point monitoring sites are shown in Figure 4. The existing rare plant trend plot will continue to bemonitored annually during Owens Valley checkerbloom's bloom period. The location of the rare plantpopulation and trend plot are not disclosed in Figure 4 due to the sensitivity of the species.

Five Bridges MitigationPhotopoints and Transects

# PhotopointTRANSECT

Note: Imagery is 2009 condition.

+ 0.6

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Figure 4. Five Bridges Mitigation Photopoints and Transects

Additionally, LADWP may rely on other data sources for insight to conditions in the mitigation area, suchas LADWP line point vegetation data from these parcels that dates back to 2004. This line point data isintended to be used for only for guidance on identifying problem areas and trends rather imposing

percent cover and diversity success criteria.

5.0 Reporting

LADWP will provide an annual report on mitigation efforts per this Plan in LADWP's Annual Owens

Valley Report as in past years. A copy of this Plan will also be provided in LADWP'sAnnual Report uponadoption by the Technical Group.

6.0 References

Inyo County Water Department. 1999. Revegetation Plan for Impacts Identified in the

LADWP, Inyo County EIR for Groundwater Management. Bishop, CA. Plan produced pursuant the 1997MOU.

LADWP. Owens Valley Land Management Plan. April 2010. Los Angeles Department of Water andPower, Bishop, CA. Plan produced pursuant the 1997 MOU.

Inyo County Superior Court. 1997. Memorandum of Understanding Between the City of Los AngelesDepartment of Water and Power, the County of Inyo, the California Department of Fish and Game, theCalifornia State Lands Commission, the Sierra Club, and the Owens Valley Committee (1991 MOU).

LADWPand County of Inyo. 1991. Final Environmental Impact Report on Water from the Owens Valleyto Supply the Second Los Angeles Aqueduct, 1970 to 1990,1990 Onward, Pursuant to a Long TermGroundwater Management Plan. SCH #89080705. October 1991.

LADWP and County of Inyo. 1991. Final Environmental Impact Report on Water from the Owens Valleyto Supply the Second Los Angeles Aqueduct, 1970 to 1990,1990 Onward, Pursuant to a Long TermGroundwater Management Plan, Mitigation Monitoring Program. SCH #89010705. October 1,1991.