Sonoma County Water Agency

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Janis Parker
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Steam Maintenance Pogam a m no So d C t.

D e C MA H oo C e ek TE IEN L CA UA AG D BLV YES BO Lilley Ceek VERANO AV nc k ee C Se c o 8TH ST Ro E ll Aoyo l e e e k C he DR ST AG E NAPA Sc w a C Fo D o m LCH GU L NO AR e s C

50-75 75-100 100-250 Owned In Fee-Engineeed Channel Easement Engineeed Channel Easement Modified Channel Easement Natual Channel Sonoma Ceek Wateshed 12 Sonoma Ceek Wateshed

1 Steam Maintenance Pogam a m no So d C t. Ho od Zone 1 A Ce e k n w oo C M L a wnd a le C Ho C ff Sonoma County Wate Agency C H o ll C e Fis K e he ek y ARM SPRI NG S R D Calabaza s C ee k W BENNETT VALLE Y So no m k a NE RO D e C MA H oo C e ek TE IEN L CA UA AG D BLV YES BO Lilley Ceek VERANO AV nc k ee C Se c o 8TH ST Ro E ll Aoyo l e e e k C he DR ST AG E NAPA Sc w a C Fo D o m LCH GU L NO AR e s C dg Son I ON ER LEV N a tha nso n C Sheet 1 Fye C Zone 8 A Zone 2 A East Fok Fye Ceek NAPA ST BROADW AY ie B O' Do wdall C C Zone 9 A Figue 4-48 Zone 3 A Below Sea level Owned In Fee-Engineeed Channel Easement Engineeed Channel Easement Modified Channel Easement Natual Channel Sonoma Ceek Wateshed 12 Sonoma Ceek Wateshed Elevation, ft. SCWA Easements ,000 1,000-1,500 1,500-2,000 2,000-2,500 Above 2, Miles SCWA Flood Contol Zone Bounday Wate Bodies Steams City Limits Reach Maps Index Souces: Sonoma County Wate Agency County of Sonoma Califonia Spatial Infomation Libay 1:160,000 Hoizon WAT E R a n d E N V I RO N M E N T 4

$E:\2008Pojects\Hoizon\SCWA\SMP\GIS\Layouts\Ch4\ReachVeg_Zone3A.$ mxd MG 12-08-08 Fye 1 Fye 1 Fye 2 Fye 3 Zone 3A 12 101 116 FIGURE 4-49 Vegetation Type Blackbey Scub Mixed

mxd MG 12-08-08 Fye 1 Fye 1 Fye 2 Fye 3 Zone 3A 12 101 116 FIGURE 4-49 Vegetation Type Blackbey Scub Mixed

canopy) Ripaian Foest Rudeal Willow Scub Developed Reaches and Vegetation Zone 3A (1 of 1) SMP Maintenance

2 Sonoma County Wate Agency Fye 4 Steam Maintenance Pogam t as E e 1 e w y Lo k F o F Fye 1 E:\2008Pojects\Hoizon\SCWA\SMP\GIS\Layouts\Ch4\ReachVeg_Zone3A.mxd MG Fye 1 Fye 1 Fye 2 Fye 3 Zone 3A FIGURE 4-49 Vegetation Type Blackbey Scub Mixed Ripaian Scub Ripaian Woodland (full canopy) Ripaian Woodland (up to 75% canopy) Ripaian Woodland (up to 25% canopy) Ripaian Foest Rudeal Willow Scub Developed Reaches and Vegetation Zone 3A (1 of 1) SMP Maintenance Reaches Souces: Sonoma County Wate Agency County of Sonoma AiPhotoUSA, ,000 1,500 Feet 1 inch equals 1,000 feet 2,000 Hoizon WAT E R a n d E N V I RO N M E N T

3 Fye Ceek Reaches 4, 3, 2 & East Fok Reach 1 JURISDICTION: LOCATION: Owned and maintained by SCWA, small potion of E. Fok is maintained though easement Downtown Sonoma between Andiex St. and MacAthu St. ADJACENT LAND USE: Residential UPSTREAM: LENGTH: Non-SCWA maintained dainage/swale (~1000 ft) Fye 4: 124 ft. Fye 3: 602 ft. Fye 2: 478 ft. East Fok 1: 683 ft. CHANNEL EASEMENT CORRIDOR WIDTH: Fye 4: 67 ft. Fye 3: 26 ft. Fye 2: 68 ft. East Fok 1: 101 ft. AVERAGE TOP-OF-BANK WIDTH: Fye 4: 41 ft. Fye 3: no data Fye 2: 49 ft. East Fok 1: 80 ft. (a) Reach 4, looking downsteam towad Andiex St. cossing. Eosion sca on the ight bank adjacent to the box culvet. Also note small bas foming in this each just upsteam of the culvet (Nov 2008). PHYSICAL CONDITIONS Reach setting: Fye ceek uns noth to south though the southwesten potion of the City of Sonoma. This ceek system appeas to be completely disconnected fom a lage wateshed, as upsteam of Reach 4 the channel quickly tuns to a small swale and then ends at W. Napa Steet. Though these eaches the channel is heavily confined by development on both sides of the ceek. Fye Ceek is a tibutay to Nathanson C, which dains into Sonoma C. Active channel: 8-10 ft wide in most locations (photo b and d), with the exception of the confluence aea in photo c and downsteam to Reach 1 whee the channel opens to ~16-18 ft wide; depths ange fom 2-2 (photo a and c, espectively). Bed sediments/textue: geneally dominated by fine sands and silts. Bank stuctue: mostly eathen with isolated aeas of ip-ap and gently sloping banks. (b) Reach 3, looking downsteam (east) fom 4 th St W. Sediments collect at the toe of the bank, along the channel magin, pinch the active channel, ceating a confined low flow channel (Nov 2008). MAINTENANCE HISTORY Channel pocesses: Channel eceives flows and sediment fom a small ubanized catchment. Most of Reaches 4, 3, 2, and the E. Fok Reach 1 show signs of deposition with a low flow channel flowing though a vegetated channel bottom (photos a and d) o a low flow channel cutting though in-channel deposits. Sonoma County Wate Agency Steam Maintenance Pogam 1

Fye Ceek Reaches 4, 3, 2 & East Fok Reach 1 Wate quality (qualitative): modeate in Novembe 2008, with limited stagnation and flows somewhat tubid o geenish.

Most aeas have shallow diffuse flow with no pools o iffles and no othe featues that would povide aquatic habitat. The confluence of Reach 2 and the E.

4 Fye Ceek Reaches 4, 3, 2 & East Fok Reach 1 Wate quality (qualitative): modeate in Novembe 2008, with limited stagnation and flows somewhat tubid o geenish. BIOLOGICAL CONDITIONS Insteam habitat: Aquatic habitat is limited by a lack of complexity in these eaches. Most aeas have shallow diffuse flow with no pools o iffles and no othe featues that would povide aquatic habitat. The confluence of Reach 2 and the E. Fok is the only aea with deep wate and significant stands of emegent vegetation (cattails). This system also appeas to be completely disconnected fom any upsteam wateshed, so it is unlikely to function as a migation coido fo aquatic species. Vegetation composition: These eaches suppot only scatteed tees, most of which ae planted edwoods (photo b) o othe landscaped vaieties. Most of the vegetation is hebaceous with gasses dominating the banks (photo b and d) and an aay of gass and blackbeies with some sedges and othe hebs gowing in the active channel. Ripaian coido and canopy closue: none Listed species with potential to occu: potential habitat fo westen pond tutle. (c) Fye C. Reach 2, at the confluence with the East Fok. The section of channel downsteam of the confluence is unique within the Fye system as this is one of the only aeas whee the channel is wide, open, and full of cattails (Nov 2008). (d) East Fok of Fye Ceek, Reach 1, looking downsteam fom 2 nd Steet W. Flow is diffuse though vegetation coveing the active channel; thee is no canopy of tees in this each. Also note the elatively naow channel easement and poximity to esidences (left) (Nov 2008). MANAGEMENT CONSIDERATIONS AND OPPORTUNITIES Management consideations fo Fye Ceek Reaches 4, 3 and 2 and Reach 1 of the E. Fok should be detemined based on flood conveyance. Obsevations in Novembe 2008 did not suggest that the cuent extent of sediment bas and in-channel vegetation ae pesenting a flood capacity issue. These obsevations should be checked and at least Reach 2 should be monitoed annually fo futue consideation of sediment emoval. Also, sediment bas upsteam of the cossing at the confluence of the E. Fok and Reach 2 should be checked peiodically as the wedge of sediment at this site appeas to be aggading and may pose a flood management issue in the futue. The same is tue fo the cossing at Reach 4, although this site does not appea to eceive much flow. These eaches could all benefit fom canopy enhancement and emoval of non-native vegetation species. 2 Sonoma County Wate Agency Steam Maintenance Pogam

5 Fye Ceek Reach 1 JURISDICTION: LOCATION: Owned and maintained by SCWA W. MacAthu St. to Todd Ave. pedestian bidge ADJACENT LAND USE: Residential UPSTREAM: LENGTH: Non-SCWA maintained dainage/swale (~1000 ft) 2,805 ft CHANNEL EASEMENT CORRIDOR WIDTH: 70 ft AVERAGE TOP-OF-BANK WIDTH: 51 ft (a) Fye C. top of Reach 1, looking downsteam fom MacAthu St. cossing. Cobble ba on the left extends into channel. Lage cobbles locally deived fom sloughed banks. Bank on the ight is gouted fo at least 150 ft (Nov. 2008). PHYSICAL CONDITIONS Reach setting: Fye ceek uns noth to south though the southwesten potion of the City of Sonoma. This Reach is staight and uns to the southen bounday of the City. Although the gadient is geneally gentle, it appeas to flatten nea the lowe end of the each with sediment deposition inceasing downsteam. (b) Middle of Fye 1, looking downsteam. Sediment collects at toe of bank, along channel magin to left; sediment also collects in mid-channel ba in distance; channel coss-section is much lage hee than upsteam sections in Reaches 3 and 2 (Nov. 2008). MAINTENANCE HISTORY Active channel: ft wide with a low flow channel anging fom 14 ft (photo b) to 6 ft (photo d); channel depths ae 8-14 ft; flow depths ange fom 2-3 ft. Bed sediments/textue: geneally dominated by fine sands and silts, with sloughed cobbles in locations (photos a/c). Bank stuctue: eathen with ip-ap cove thoughout; some sections with gouted ipap (photo a) and sacete (photo c). Channel pocesses: Reach 1 is eceiving uban unoff fom upsteam each, due to its staight alignment and modeate gadient, channel appeas to effectively convey sediments though its uppe sections. Moving downsteam, sediment deposition and ba fomation incease with altenating d-bas though the bottom of the each (photo d). Peiodic gade contol featues ae common in this each and it is not clea whethe they wee engineeed o developed in-situ (photo Sonoma County Wate Agency Steam Maintenance Pogam 1

6 Fye Ceek Reach 1 a, c and d) fom sloughing local ock mateials. Wate quality (qualitative): modeate in Novembe 2008, with limited stagnation and flows geneally clea. BIOLOGICAL CONDITIONS Insteam habitat: Aquatic habitat complexity and function inceases moving downsteam. In the upsteam sections of Reach 1, the channel is confined between gouted banks and aside fom eoded ip-ap displays little in the way of complexity. In the middle and lowe sections, deep uns (photo b), pools, and iffles occu in elation to sediment bas. Also, unlike the upsteam eaches, Reach 1 maintains shaded conditions fo much of its length. Vegetation composition: Reach 1 suppots a dense, naow, ipaian canopy fo much of its length. The only aea that is devoid of ipaian canopy is the westen bank at the top of the each (photo a). Ripaian tees include maples, aldes, edwoods, fis, and othe conifes. Undestoy is geneally limited to gasses and duff unde the dense canopy. In channel vegetation is also limited to shade toleant hebaceous species thiving on the channel magins and on the sediment bas. Ripaian coido and canopy closue: Ripaian canopy closue is aound 50% though most of the each, with some aeas of between 25%-50% (photos a and b) and some aeas highe than 50% (photos c and d). Listed species with potential to occu: potential habitat fo westen pond tutle and listed plants. (c) Fye Ceek Reach 1, looking upsteam fom mid each. Sacete used to stengthen bank to left, ock and log ceating gadient beak in steam (nea gound) with pooling upsteam, and faste flow downsteam (Nov, 2008). (d) Lowe Fye C. Reach 1, looking upsteam fom the pedestian bidge adjacent to Todd Ave. Ripaian canopy now geatly expanded; in-channel sediment/ba fomations also moe stongly developed in the lowe each (Nov, 2008). MANAGEMENT CONSIDERATIONS AND OPPORTUNITIES Management consideations fo Fye Ceek Reach 1 focus on sediment management in the lowe sections of the each. Field obsevations suggest that cuent conditions ae not poblematic fo flow conveyance and capacity, but if sediment bas continue to aggade they could be poblematic in the futue. Vey few othe maintenance issues wee obseved duing field econnaissance in Novembe Sonoma County Wate Agency Steam Maintenance Pogam

Nathanson Ceek Bypass JURISDICTION: LOCATION: Owned by City of Sonoma, maintained via easement Adjacent to Fine Ave. and paallel to Dewell D. ADJACENT LAND USE: Nathanson C.

7 Nathanson Ceek Bypass JURISDICTION: LOCATION: Owned by City of Sonoma, maintained via easement Adjacent to Fine Ave. and paallel to Dewell D. ADJACENT LAND USE: Nathanson C. Pak, and Residential UPSTREAM: LENGTH: Modified eaches, nonmaintained by SCWA CHANNEL EASEMENT CORRIDOR WIDTH: AVERAGE TOP-OF-BANK WIDTH: (a) Nathanson Ceek looking downsteam to inlet of the bypass channel (to left) and the Nathanson C. channel (to ight) Nov, (b) Fom top of Nathanson Bypass, looking downsteam. Notice the bypass is simply a wide tapezoidal channel. SCWA conducted vegetation maintenance in the summe of 2008 leading to the conditions obseved in Novembe MAINTENANCE HISTORY PHYSICAL CONDITIONS Reach setting: Nathanson Ceek is a modified channel flowing noth to south though the City of Sonoma. The bypass channel (located in Nathanson C. Pak) povides stomwate divesion when flood wates ae high enough to ente the inlet (photo a) and inundate the wide gadient bypass (photo b). Active channel: ~30-40 ft fom toe to toe, shallow depth 2-4 ft. Bed sediments/textue: geneally a mix of gavel and coase sand with fine mateial deposited behind stumps. Bank stuctue: vey wide channel with gentle tapezoidal banks, banks ae eathen. Channel pocesses: The inlet elevation is set by the bed elevation of the inlet (photo a) when wate ises in Nathanson C and entes the inlet, flows then ente the bypass. The bypass is wide and maintains a vey low gadient (photos b and c); at downsteam end of bypass, the channel naows, steepens, and meets the ceek again (photo d). Wate quality (qualitative): dy unless flooding, channel mostly collects leaf litte Sonoma County Wate Agency Steam Maintenance Pogam 1

8 Nathanson Ceek Bypass BIOLOGICAL CONDITIONS Insteam habitat: Aquatic habitat is limited to punctuated events when the bypass floods and is tempoaily inundated. Obsevations suggest that inundation does not last long enough to suppot aquatic habitat. None the less, vaious aquatic species might migate though o foage in the bypass eithe in dy o wet conditions. Vegetation composition: The bypass was geneally devoid of vegetation duing field econnaissance in Novembe In pevious site visits, extensive thicket of blackbey with occasional willows coveed majo sections of the bypass. Ripaian coido and canopy closue: none Listed species with potential to occu: The bypass does not cuently contain suitable habitat fo listed aquatic species. (c) Lowe Nathanson Bypass, looking downsteam. Notice the ecent vegetation management, with the cleaing of lage willows (see stump in the foegound) (Nov 2008). (d) Fom the bottom of the Nathanson C. Bypass looking upsteam. Eathen bem on the left of the photo, to the left of this bem is the mainstem of Nathanson Ceek. Also notice that the x-section of the bypass naows significantly and gade inceases significantly at the outlet whee flows ae etuned to the mainstem (Nov 2008). MANAGEMENT CONSIDERATIONS AND OPPORTUNITIES The Nathanson C Bypass equies peiodic vegetation maintenance, as was conducted in In addition, since the bypass functions as a slack wate envionment duing flooding, significant sediment deposition occus. Depending on impacts to capacity, SCWA will need to emove sediment peiodically. 2 Sonoma County Wate Agency Steam Maintenance Pogam

Water flows through the voids in a soil which are interconnected. This flow may be called seepage, since the velocities are very small.

Water flows through the voids in a soil which are interconnected. This flow may be called seepage, since the velocities are very small. Wate movement Wate flows though the voids in a soil which ae inteconnected. This flow may be called seepage, since the velocities ae vey small. Wate flows fom a highe enegy to a lowe enegy and behaves