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Home My WebLink AboutAgenda Bill 5.A 09/20/20045A CITY OF PETALUMA, CALIFORNMA. :4 . Agenda Title: Meetin2 Date: Discussion and Po'ks Action Regarding SCWA Stream September 20,2004 M_ aintenance Plans Meeting Time: M 3:00 PM ❑ 1 7:00 PM Cate2ory (check!one): 7 Consent Calen'dar' ❑ Public Heafrin'g Z New Business F Unfinished Business ❑ Presentation Departme Director: Contact Person: Phone Number: Water Resources and Michael Ban, P.E Dean Eckerson, (707) 778-4304 Conservation ' P.E. Cost of Proposal $0 Account NumberN.A. Amount Budp_ete' :$0 'Name of Fund: N.A. Attachments to Agenda `Packet Item- Exhibit A'- SCWA Zone .2A Flood Control Map Exhibit B - SCWA Stream Vegetation,Mdin,tenance Options Summary Statement: Surface drainage 'and flood protection for the City of Pqtaluma.is provided by the Petaluma River, its tributary creeks and channels,. and - A network of culvert's and storm, drains... Many of the natural creeks and channels are maintained by the Sonoma County Vater Agency through permi'ssive clearing easements granted by the, City tdthe� Agency.-. However, these easei easements do not define the level of maintenance required, ridfdo they"obligat& the Agency toyroviae a specific level of 'flood protection. The Agency is developing plans for stream maint.enance, activites and is requesting' input from the City on the type and extent , of stream - maintenance act , i'vit6s"'provid6d through the permissive clearing easements. City management understands the need to balance :flood protection with the protection and enhancement of valuable creek habitat and recommends the Agency. p consistent -and ongoing stream maintenance activites to ensure both needs are met. Ree - 6nitfiended City-touncItAction/S . u2eested Motion' `Direct the Sonoma County - Water Agency to gerform those ,stream maintence activities, as necessary, to provide adequate flood,•oteotion and promote the deve . lopment of natural stream habitat through the permissive clearing ,easements granted by the City to the Agency.• I'Revie-40dby Fingh I c - e'Diftctbr- .- Reviev4dofiT �--nev: 2004 ApprovAd ky City Mann e Date: I)atEP c�s'b_ L ate: Rev i sion an ' - Revise d: Ibb e File Code: S:\water resources & # Sef/ember 3,2004 conservation\Sform - Water\SCWA Stream Maintenahce\2004 Agenda Bill.doc i CITY OF PET'AUUIVIA,; CALIFORNIA SEPTEMBER 20, 2004 AGENDA REPORT FOR DISCUSSION AND POSSIBLE -ACTION REGARDING SCWA STREAM M AINTENANCE PLANS EXECUTIVE SUMMARY Surface drainage and flood protection,for the City of Petaluma is provided by the Petaluma River, its tributary creeks and channels, and a network of culverts and storm drains. Many of the natural creeks and channels are maintained by the Sonoma, County Water.Agency through permissive clearing, easements, granted by the City to. the Agency: However, these easements do not define the level of maintenance; required, .nor do they obligate. the Agency to provide a specific level,of flood protection. The Agency is developing,plans for stream maintenance activities and- is requesting input:from the City on the type and extent of 'stream maintenance activities provided through the permissive clearing easements management understands the need to balance flood protection With the protection and enhancement of valuable creek habitat and recommends the Agency perform consistent and .ongoing stream maintenance activities to ensure both needs are met. 2. BACKGROUND The Sonoma County Water Agency (Agency) is responsible for operating and maintaining many of the creeks and channels in.the City of Petaluma. These &ai age. facilities lie within the Agency's Flood ControltZone 2A, encompassing the 'Petaluma River watershed, and provide surface drainage and flood protection for the City. The activities;nvolved in-the maintenance, and operation of 'channel, facilities owned.by the Agency and constructed in accordance with the standards and specifications' adopibd.by the Agency Board of Directors may be broken into seven general categories: (I) :Landscaping, (2) Fencing, '(3), Mowing, (4) Structural Repair, (5) Grading and Reshaping, (6) Debris Removal, and' (7) Spraying. ' The Agency also -holds permissive clearing easements granted by -the City for some of the natural creeks and channels in Petaluma for the purpose of maintaining, repairing, or reconstructing drainage' These easements allow the Agency ,to maintain these streams; however, they do not establish a level of : protection the Agency is! obligated to maintain and they do not impose any'niaintenance obligations on the Agency since' "they are not owned by the Agency. The attached Exhibit A (Zone 2A Flood Control. Map)` depicts the'various facilities'throughout City'ma ntained,by the Agency. Exhibit A also,provides brief descriptions of -the flood control maintenance activities for the °'three types of facilities shown on the map: (1) Engineered Flood Control' Channels owned bythe Agency, (2) Engineered Flood Control'Channels owned, - others, and (3) Permissive Clearing Easements for natural creeks owned by others. The Agency has examined its inaintenance�prograin based on concerns raised by the • public and 'various; resource -agencies regarding the amount of vegetation removed from several streams in 2003. In response to these concerns - the Agency is developing plans for stream -maintenance activities, and requesting: input from the City on how to balance environmental and flood control needs'on creeks owned by the City. 3. ALTERNATIVES The, amount of flood protection.provided by a is closely related to the amount and type of vegetation the stream floor'aiid banks.. `When not regularly maintained, streams originally designed to : provide flood protection for a 100 =year storm event may not have adequate capacit -to provide the design level of protection. The Agency has developed five maintenance options for streams offering`varying levels of vegetation removal and flood protection. These. options,are listed below and. llustrated.in the attached.Exhibit B. The level of flood protection described.in each option is. ap proximate; - detailed computer modeling is necessary to; provide; more accurate: flood protection estimates. Option l. - No Maintenance i Under the No Maintenance option natural vegetation'in a stream designed to provide flood protection for a specific area would.be allowed to grow without restriction or maintenance. This opt `ionwould maximize thexiparian.habitat in a stream, but would only .provide floodprotection for 10- year'to:25 =year storm events. Option 2'� �Str. eam Floor Maintenance Vegetation on the stream - floor would be removed as part of, this- maintenance option. Seasonal grasses on the stream floor would not:be removed Some vegetation on the stream banks maybe removed to provide access to the strearn floor. This ,maintenance program would,provfde flood protection for 25- yeario 50 -year stonn.events. Option; 3 Partial S"tream.Bank.Maintenance Based on observations during high flow' conditions multi -trunk trees on the stream banks'were found to significant.quantities of debris. Additionally, single -trunk trees With limbs located, below,the top,' of the istrearn bankalso accumulated significant quantities of debris: Urid`er this`maintenance option, the; . stream floors would be cleared of vegetation. Multi -trunk trees on the stream'banks would either be trimmed to forma single trunk or cut,down.entirely- Invasive: exotic trees and bushes would also be- removed on a -by -case basis. Single trunk- trees would be trimmed so their limbs are above the top of bank. No under story vegetation ( "such as blackberries bushes .or small trees) would'be'removed except to provide' access to treest being trimmed or"renioved. This option would provide flood protection for 40- year 7.5 year storrn,:events. Option 4 Stream Bank Maintenance and Canopy Development This- maintenance option; would con "sist of rernovirig (1) vegetation- from the stream ;:floors (2) under story'vegetation from the: stream banks, (3) exotic trees on a case -by -case basis; (4) multi - trees from the stream banks,. and (5) tree branches below Ihe�top of the steam bank. Single4ftink:trees along -the stream, ban ks would be removed to form lines oftree& parallel to the flow direction. i - f This option would also include re- vegetation! in aeas, where the tree spacing- exceeds 20 _feet .on the southerwand western sides of the creek,.banks, sand 40,feet on the northern, and eastern sides:• Selected'trees would.be removed dunng;the. suinrner maintenance period,,arid re vegetathori.'with 2� native canopy - .forming trees would: occur during the winter. The trees would be planted in lines parallel to the direction of flow: Thi's iaintenance program would provide flood protection for 60 -year to 1.00 =year storm events,. Option 5- Original Design, Maintenance For some streams, maintaining the original design level of-protection would require removal of all vegetation, except, seasonal grasses, within the active portion of the stream. However, it is unlikely approval for this levetof maintenance could be obtained from the Regional Water Quality Control Board, California Department of Fish and Game, or the National Atmospheric Oceanic Administration Fisheries.: This option would provide flood protection for 100 year storm events. 4.. FINANCIAL IMPACTS None. 5. CONCLUSION Surface drainage „and. flood, protection forpublic and private property, throughout Petaluma is provided by the Petaluma River, its tributary creeks and channels, - and an extensive network of culverts and storm drains. Maintenance and operation of`mosfof`these facilities is the responsibility of either the City or the Sonoma County Water. Agency. The permissive clearing easements granted by City to the.Agency do not �definethe level of maintenance required and do not obligate the Agency provide a'specific level. of flood protection. However, removal and control of vegetation in the waterway is necessaryto retain the water- carrying capacity of the creeks and d channels, thereby providing, greater” protection against floods. In addition to providing flood protection, our creeks and channels also provide valuable habitat for fish and wildlife. Tree- lined: creeks, in particular, provide protection for fish while shading the water to keep temperatures cool. Accordingly, planning and performing stream maintenance operations requires a careful balance offlood protection and environmental protection. As requested bythe Agency, the City, must provide adequate .direction and inpuf.to ensure the work performed through the permissive clearing: easements contributes to the.long -term sustainability of our community and the Petaluma River watershed. 6. OUTCOMES `OR.PERFORMANCEIMEASUREMENTS THAT WILL IDENTIFY SUCCESS OR .C.OMPLETION;: Consistent and ongoing maintenance activities performed by °the Sonoma, County Water Agency on natural creeks and, channels, through permissive clearing' easements granted by the City to the Agency. !Successful performance of these actvities by the Agency will ensure adequate surface drainage and "flood protection for our community, as well as.protection and enhancement of creek habitat for fish and,wildlife.. 7. RECOMMENDATION City management recommends the Sonoma County Water Agencyprovide the necessary level of maintenance `to maximize:flood carrying capacity and promote canopy development on those facilities where, the City has granted clearing easements to the Agency. This will .ensure 3 adequate, flood protection for public and private property.and provide valuable habitat- for fish and wildlife. Within. the stream corridor. As depicted on Exhibit B, Option 3 consisting of partial stream bank maintenance and canopy development appears to bestmeet °needs of the City: 'In isolated areas where the conveyance capacity. may be limited, the Agency should remove additional under story vegetation, as depicted in Option 4. Examples of'stream',corridors in need of the removal' of under story vegetation .include °the Petaluma River between Corona ,Road.and the function of Capri. Creek, East Washington Creek between Garfield-Drive and Ely -Eoul"evard.. and Corona Creek between Ely Road and Sonoma Mountain Parkway. ►�J EXHIBIT A SONOMA. COUNTY WATER AGENCY ZONE 2A. FLOOD CONTROL MAPS • • . .. . .... .... -------- ---- 131 C. Pef.,adlurna Rliver,'... 0 850 1700 3400 iFeet, L. ZONE 2A FLOOD CONTROL MAP Engineered Channel-Owned inTee Engineered Channel Easl§rhenf Natural Channel, Permissive�Clearing Easement N 1V T SCWA,Focihtv Guide 3-22 cl ....... .... .... p cotatl E ucal y ptus u 'o 1 A ' F ast ad Avehue 131 C. Pef.,adlurna Rliver,'... 0 850 1700 3400 iFeet, L. ZONE 2A FLOOD CONTROL MAP Engineered Channel-Owned inTee Engineered Channel Easl§rhenf Natural Channel, Permissive�Clearing Easement N 1V T SCWA,Focihtv Guide 3-22 m Q m. Y :' c , O �j a `n _ O' � Q' fr .. U �g \a\ II3 u a� Q jL O I J c Zli fn 7C3 Q sjQ O ILL cS , f �a Q 0 L c c _ _ a CU P / p N aD ' _ U o m, a�ess i .O � �, � �� 4 � ./ cu F1 F " ` �op ooMpa� Jp r _•,f ,' � j ,. f c y /;' �� .. i:'' � {• —r'-� sp a Aoc WeyU W la� uosdWo4j �l N uueil Qo .� Q . .' a rA P G Road -, - o a; / - J, P ?O'd SC33AT- gcili�u Guide,3 -33 • r = f - w 2 A �d Washington Creek r�; ! �a Lynch 'Creek.. \ ' East B < r .. / ; ,`, / ! n`Jrp; ✓I P \ - J East Washington Creek, 0a PETALUM �I \.. �p�J,. � 101 / , / i l / a _ >. \ y- . ✓ 7 / ` !,X, ;; /: , !✓ ti r\ { � / ✓ ` ' p �a, j / r / / i / /i'... `\ ,! \� �� p � ` ) r ' \ \ /ga � �: • ' � %' � � � / �\ ~'— : ork i _ 'McDowell Creek 116 ~ s m, <` r ''�ll�cpowejJ I i . °eraJp °ela /un>a z \ Ad0be'Creek J, r McDowel!I Creek t - gpU i� 4 ! _ $t (eet t _~ ' \t`fo4r3 r , Thompson Creek 4 G driy' Shoe f 2 . Ellis Creek 101: � ®I ZONE' 2A FLOOD CONTROL MAP . Engineered Channel Owned in Fee 0 750 .1500 3000 Feel Engineered Channel Easement, "+ Naiural Channel, Permissive -C learing;.Easement 5 s e, A ' �'ta /o etal�m `l Adobe: Creek _ Z �l 116 Schut •� -. -400' - _- , .-Antonio s San Mann Ceunty.__. .. . ... ...� ` Antonio 'ZONE 2A FLOOD CONTROL MAP N 'Engineered Channel. Owned in'Fee o: 750 1500 3000 Feel ® Engineered Channel, Easement Natur' l Chan nel,,Permissive.Clearing Easement s. Sj • - ry �0 - sgo �.. ,101' _- IJp / Schut •� -. -400' - _- , .-Antonio s San Mann Ceunty.__. .. . ... ...� ` Antonio 'ZONE 2A FLOOD CONTROL MAP N 'Engineered Channel. Owned in'Fee o: 750 1500 3000 Feel ® Engineered Channel, Easement Natur' l Chan nel,,Permissive.Clearing Easement s. SOMOMA COUNTY WATER AiGENCY 8RIEF DESCR 1 1PTION: OF FLOOD CONTROL i `RED — ENGINEERED FLOOD CONTROL CHANNEL OWNED IN FEE BY WATER AGENCY: COMPREHENSIVE MAINTENANCE: INCLUDES,_SEDJMENT REMOVAL; BANK STABILIZATION; VEGETATION MANAGEMENT; FENCE AND GATE MAINTENANCE .BLUE — ENGINEERED FLOOD CONTROL CHANNEL EASEMENT OWNED BY 'OTHERS-!BUT HYDRAULIC CAPACITY AND CHANNEL INTEGRITY MAINTAINED BY WATER AGENCY.. MAINTENANCE INCLUDES; SEDIMENT REMOVAL; BANK STABILIZATION; VEGETATION MANAGEMENT ONLY WITHIN'CHANNEL TO MAINTAIN HYDRAULIC CARRYING CAPACITY GREEN NATURAL CREEK PERMISSIVE CLEARING' EASEMENT OWNED BY OTHERS: WATER AGENCY, IF DEEMED- NECESSARY`TO PROTECT ADJACENT PROPERTY, MAY RESPOND; TO! CLEAR DEBRIS VEGETATION JAMS AND SNAGS TO RESTORE CARRYING CAPACITY AND CREEK ALIGNMENT Note: Red, Blue and, Green define,maintenance descrintions of delineated creeks and channels #ound in the Water ,4gency's Facility Guide. 1\RS2SCWA ,PClrs2lulomlbobo \FLOOD CONTROL1Generallma 'intDescription.doc � 04 SONOMA CGUNTY WW TERAGENCY STREAM VEGETATION MAINTENANCE. OPTIONS • ' il�� I I '*' Iq I I 1� 1111i I � � I L in A OPTION 1 — No Maintenance Estimated flood protection provided: Accommodate 10 -25 year rainfall event Without flooding • Remove all understory vegetation (blackberries, non — notive trees, e.g. tree of heaven, eucalyptus, acacia) from stream banks • Remove additional trees to form limes of trees parallel to the direction of flow. Estimated flood protection provided: Accommodate 60 -100 year rainfall event without flooding • Remove all trees, bushes, & cattails from stream floor & stream banks • May not be acceptable to NOAA Fisheries, California Department of Fish & Came and /or Regional Water Quality Control Board Estimated flood protection provided: Accommodate 100 year rainfall event without flooding * Estimated flood protection assumes no sediment buildup in streams R—..d.. 62P" OPTION 5 — Original Design Maintenance trea a*intenance ,2004 � , ;N � �S MA Why, maintain streams ?f`� fi . Stream maintenance is= perforrried primarily for flood protection. By removing ' vegetation in the waterway, we ,can retain the water- carrying capacity of the ; channel, thereby ,providing ,greaterprotecton against floods. However, when we consider removing vegetation' we must also consider. its habitat value, to fish and wildlife. Trees,, m particular,. provide p I g ps to keep the t temperature cool. So lannm and,, erformin stream mai protection for fish wliile also shadin the water, which hel p p . „ .g „ p , g nfenance requires a careful . balance of flood protection and environmental ,protection: All of the stream maintenaiice.activities we perform are permitted by both the Regional Water Quality Control Board and the California Department of Fish and Game.: 1Nhen.is maintenance done ?'. The allowable window for performing istream maintenance is actually very small. We can't start work until the site is free:of nesting bards, and all activities inAhe'stream channels must be complete by Oct. 15, before the rainy season So :we must'work quickly once our`biolog sts deterrnine that the nesting is complete. How do'we choose the sites' to- maintain ?" SCWA performs maintenance on approximately 83 miles of.improved (flood. protection channels countywide. Each year, we perform an inventory, including flow models, -and compare each site's actual water - carrying capacity against its design capacity; :Based on the results, we.prioritize approximately ten miles of stream each summer for maintenance. What work will be done, and. how? SCWA has permissive easements for the! sites in Rohnertzpark° and,Petaluina, and those.easements allow I s to perform maintenance. They do, riot, .however, - require us to maintain, any particular level,.of flood.. . protection. So in 2004, for the, first time, SCWA, asked, the city councils to work with us in determining the level of maintenance to be petforrried in their cities: Basically,' crews will make two passes at.each site. The first pass will remove trees from the stream channel, thin multi trunk, trees down to, one trunk and .trim lower. branches. Weeks later, crews will use mowers and weed whackers remove ;grasses, shrubs: and non- native vegetation, including, on a case -by -case basis, blackberries, The only chemicals used will be to treat stumps of trees removed from the creek channel: Who actually. *does the work? This summer's work will,be completed by SCWA staff, .supervised adult crews of minimum security inmates from the North County Detention Facility and a- contract inowing service. Wh'at will be maintained. this summer? PetAluma, Washington Cie& Ellis Road to the confluence with. Petaluma River; and McDowell to Hwy. 101 Corona Creek:, Ely Road to Sonoma MoWit a Parkway Adobe Cte& ,So. McDowell to Lakeville'Highway East Washington Cree�k: Ely R'oad',tb Garfield Rohhert-Park 'i Copeland Creek: Seeffarinto Commerce Blvd., .and Countr Club Dr. to Jasmifte Ct, Five Creek: Snyder to the confluence with'Crane Creek Wilfred Creek' Snyder Lane to, confluence with Coleman —4 Creek Coleman Creek" Snyder - Lane to Hillview Way,, and S nyder -Lane to confluence ,with Cook Creek Laguna. do Santa-Rosa: -Rosa: From confluence with 0, o§sage Creek 0,,Stonv PointRoadi East Cotati Ave. to, Qxaveirist;ein Way; and Gravenstein Waylo. Commerce Blvd. Santa Rosa Colgan Creek- cbrbyAve. to the railroad tracks Santa Rosa Creek: Willowside Road to confluence with Peterson. Creek Guemevill& Wenidell-C Creek: Upstream of Road 'to, end of `SC - W.A stretch (1 869 Jinear feet) Pauii ree'k: From 4pprokimately 1 Stoe-IeLatie, Roieland,Creek-: In.'felds upstream of double act as.dobris leg, es that curre ntl Pi heir. Creek:; Hopper. Ave. upstream to end of 'S',CWkstieich (460 linear College! Creek:, From -dirt overcr6ss to. and culvert - Austin. Creek: Middle Riiricon to channelized portion and, confluence, with Ririconada Creek- Brush 'Creek: 540 near the confluence With Austin Creek- 200 feetdownstream of confluence with Austin Creek to the end of the stand of willows , (Z 600 linear, feet) Sierra PaTkChanneL Drive. to confluence with'Sp n Creek. Todd rttlrom D61oresLane to the Bellevue conduit • AiroChannel,: Skvlane.Bbulevar to the railroad How ffin`d'out more Contact:Elizab&ih '6ft Water A at Sonoma County gotic'y by calling (797)524 . -76 1 204 or by s6nding,e- . -mail to - 6iiiffieti@scwaica-.gov. • 0