Coastal Development Permit Waiver Application Arroyo Grande Creek Flood Control Channel Vegetation Management Project 2007

Transcription

1 Prject Descriptin fr CDP waiver applicatin 2007 Page 1 f 23 Castal Develpment Permit Waiver Applicatin Arry Grande Creek Fld Cntrl Channel Vegetatin Management Prject 2007 Figure 1. Vicinity Map: Zne 1/1A Fld Cntrl District (black utline) receives runff frm the Arry Grande Creek Watershed (red utline).

2 Page 2 f 23 Cntents I. Update: Brief summary f events related t the Arry Grande Creek ( AG Creek ) fld cntrl channel since 2006 CDP Waiver W. II. III. IV. The Big Picture: Backgrund and histry f AG Creek fld cntrl channel, as well as mre in-depth discussin f imprtant recent events. Prject Descriptin: Cmplete descriptin f the prpsed vegetatin management prject. Summary f Request t the Castal Cmmissin: CDP Waiver fr Summer and Fall 2007 IV. Literature Cited Exhibit A: Final Arry Grande Watershed Memrandum f Understanding Exhibit B: City f Arry Grande Ntice f Public Hearing Exhibit C: Arry Grande Creek Fld Cntrl Channel Vegetatin Management: A pht series

3 Page 3 f 23 I. Update Events f the past year since 2006 CDP Waiver W This prpsed vegetatin management prject in the Arry Grande Creek ( AG Creek ) fld cntrl channel ccurs in the cntext f many ther activities aimed at implementing a watershed-wide apprach t decisins affecting Arry Grande Creek and its tributaries, and develping a lng-term management strategy fr the fld cntrl channel itself. Lcal gvernments, rganizatins and cmmunity members are wrking tgether t imprve crdinatin and effectiveness in managing the watershed. Fish passage barriers are being remved and studies cnducted t mnitr the health f the fisheries in the creek. Funding is being pursued fr prjects which will imprve stream habitat, restre fldplain capacity, and reduce sedimentatin. The City f Arry Grande has drafted a creek prtectin rdinance which establishes special standards fr develpment f prperty adjacent t creeks. While sme f these effrts were spurred initially by a desire t minimize the adverse effects f upstream develpment n fld risk t thse living at the bttm f the watershed, all f the prjects and plicies take int cnsideratin prtectin f the riparian habitat and sensitive species which find their hme in AG Creek and its tributaries. Belw is a summary update f AG Creek watershed-related events that have taken place in the past year, since the 2006 CDP Waiver applicatin ( W). Develping a lng-term plan fr management f the AG Creek fld cntrl channel The Zne 1/1A Advisry Cmmittee Task Frce is meeting regularly with SLO Cunty Public Wrks envirnmental planners, and have selected Alternative 3C frm the 2006 Arry Grande Creek Ersin, Sedimentatin and Flding Alternatives Study as the prpsed prject fr lng-term management f AG Creek SLO Cunty is drafting a Ntice f Preparatin and a Request Fr Prpsal Qualificatins fr cnsultant applicants t prepare an envirnmental impact reprt/envirnmental assessment and assist with regulatry permitting. It is anticipated that cmpleting envirnmental review and btaining envirnmental permitting (prgrammatic agreements, castal develpment permits, etc.) t implement cmpnents f the lng-term plan, particularly sediment management, will take tw t three years. Regulatry agencies invlved in this prcess will include at a minimum the U.S. Fish and Wildlife Service, Califrnia Department f Fish and Game, Army Crps f Engineers, Califrnia Castal Cmmissin, NOAA/NMFS, SLO Cunty, and RWQCB. Watershed apprach: the Memrandum f Understanding ( MOU ) The final versin f the Arry Grande Watershed Memrandum f Understanding (MOU) recently cmpleted final review by the Cunty f San Luis Obisp and the City f Arry Grande, and is being circulated fr signatures. A cpy f the MOU is attached as Exhibit A. The purpse f the MOU is t prvide a tl imprve cperatin and crdinatin amngst all watershed stakehlders t develp recmmendatins t fund prgrams and develp plicies fr the maintenance, prtectin, and enhancement f the Arry Grande Watershed and the creeks within the Watershed. AG Creek Watershed wrk in prgress: On August 22, 2006, the Arry Grande City Cuncil extended fr an additinal year the interim mratrium n develpment within 25 feet f the creek, which was initially implemented n September 27, 2005.

4 Page 4 f 23 The City f AG has drafted a cmprehensive stream prtectin plicy, in the frm f general plan and develpment cde amendments, wrking with partner grups such as the CSLRCD, the NRCS, and Central Cast Salmn Enhancement. A public frum t discuss the draft plicy amendments is scheduled fr June 5, 2007 (Exhibit B). Central Cast Salmn Enhancement (CCSE), via funding frm CDFG, versaw cmpletin f a fisheries assessment f Arry Grande Creek during Octber 2006, building n the knwledge abut the creek s cnditin btained via the 2004 stream habitat typing cnducted by the Califrnia Cnservatin Crps. The draft reprt n the 2006 AG Creek fisheries assessment is in the review stage. The Califrnia Department f Parks and Recreatin cnducted fisheries surveys in the lagn and immediately adjacent upstream prtin f AG Creek in February 2006, June 2006, September 2006, December (Fr 2006 summary reprt, g t: (Rischbieter 2006) The draft Habitat Cnservatin Plan (HCP), develped by the San Luis Obisp Cunty Fld Cntrl and Water Cnservatin District t address the vlume and timing f in-stream flw releases frm Lpez Dam int Arry Grande Creek, cntinues review by the US Fish and Wildlife Service and the Natinal Marine Fisheries Service. CCSE, thrugh a grant frm CDFG, is verseeing redesign f the stream gage n Arry Grande Creek s that the gage n lnger pses a barrier t steelhead trut migratin. CSLRCD is wrking with the City f AG and ther agencies t identify funding and cmplete prject design fr pririty fldplain enhancement and sediment reductin prjects in the AG Creek watershed. AG Creek fld cntrl channel vegetatin management: Results f 2006 prgram On September 8, 2005, the Castal Cmmissin granted the CSLRCD a Castal Develpment Permit Waiver fr selective vegetatin thinning in the castal zne prtin f the AG Creek fld cntrl channel (Waiver # W). With funding frm SLO Cunty, the CSLRCD then crdinated the vegetatin thinning wrk, with the help f Califrnia Cnservatin Crps crews, fllwing the specified guidelines. The CCC s wrk included maintaining a vegetative buffer f willw trees t shade the creek, while trimming the lwer tree branches t lessen resistance t high flws and decrease the risk f debris jams. The 2005 vegetatin thinning in the castal zne marked the first time that such wrk had been dne in the riginal jurisdictin castal zne since the mid 1990 s. On Octber 11, 2006, the Castal Cmmissin granted the CSLRCD a new Castal Develpment Permit Waiver fr selective vegetatin thinning in the riginal jurisdictin castal zne prtin f the AG Creek fld cntrl channel (Waiver # W). The vegetatin management wrk thrughut the entire fld cntrl channel in 2006 was cmpleted during the perid August 14 thrugh Nvember 3, 2006; wrk in the riginal jurisdictin zne was cmpleted by Octber 31, 2006; an extensin t cmplete wrk elsewhere in the channel thrugh Nvember 3 was granted by the CDFG. Figure 1 prvides an example f the density f willws in the reaches f the riginal jurisdictin castal zne where vegetatin management had nt been cnducted since the 1990s.

5 Page 5 f 23 Figure 1. Lking acrss the creek at dense streamside willws in area just abve Guitns crssing that have nt been thinned fr years. Limited crew availability in 2006 due t Califrnia s wildfire seasn meant that sme stretches f the creek, such as this ne, were left unthinned. Overhanging willws like this increase risk f capturing debris transprted during high flws and creating debris jams, in additin t increasing verall channel hydraulic rughness, which slws flws. In cntrast, Figure 2 shws views lking suth acrss the creek in where willws were thinned in 2006, with the residual benefits in terms f decreased vegetative rughness in the lwer 6 feet f the willws still evident the fllwing year, in May 2007, while upper canpy and herbaceus grundcver flurish. Figure 2. May 25, Lking suth acrss creek at bank where willws were thinned and pruned in fall 2006, and still shw benefits f vegetatin wrk several mnths later.

6 Page 6 f 23 Additinal examples f the results f vegetatin management in the castal zne in 2006 are prvided in Figures 3 thrugh 6, with phtgraphs taken this spring. Figure 3. March 22, Nrth levee in riginal jurisdictin castal zne belw Guitns crssing fllwing vegetatin management wrk the previus fall. Since spring has nt yet begun, there has been very little regrwth, bth frm the pruning and frm winter leaf drp. Figure 4. May 25, The same reach as in Figure 3, a few mnths later in May 2007, shwing grwth f herbaceus grundcver, as well as the beginning f base spruting f willws.

7 Page 7 f 23 Figure 5. May 21, In castal jurisdictin abve Guitns crssing where bth sides were pruned in fall lking upstream. Nte the penness in the lwer tree trunks, while the upper canpy clses ver the creek. Figure 6. May 21, In castal jurisdictin abve Guitns crssing, where bth sides were pruned in 2006 (lking dwnstream). Again, the lwer prtin f the willw stands retain penness frm pruning and thinning in 2006, while upper canpy shades the creek and herbaceus vegetatin prvides generus grundcver. Figures 2 thrugh 6 demnstrate the benefits f the vegetatin management wrk that was perfrmed in 2006, shwing that several mnths later the willws retain penness n the lwer six feet f their trunks. This means that less wrk by crews will be required in 2007 t reduce hydraulic rughness and maintain basic fld capacity, while maintaining upper canpy t shade creek. The wrk in 2007 in these reaches f the fld

8 Page 8 f 23 channel will cnsist primarily f pruning f base shts and side shts, t cntinue t train willw grwth int the upper canpy. Because f limited availability f the CCCs crews in 2006, including being called away t wrk n wildfires thrughut the state, wrk was nt cmpleted n all stretches f the channel. Cnsequently, sme stretches f the riginal jurisdictin castal zne still have nt received vegetatin management fr ver a decade, and still have very dense stands f willws that increase risk f flding, such as in the reach shwn in Figure 1. During the curse f vegetatin wrk, red-legged frgs were bserved in mre than 8 lcatins by RLF mnitrs, and buffer znes were established t prtect thse sites during vegetatin management activity (Figure 7). Figure 7. Octber 19, Right (suth) side f AG Creek abve 22 nd Street Bridge was thinned by CCCs a few days earlier, while the left (nrth) side and center island remained unthinned due t presence f red-legged frgs. Upper canpies n bth sides remain thick, while thinning has prduced penness between lwer willw trunks n the suth side. The reaches f the creek which have been thinned and pruned ver the past 3 three years will require much less wrk in 2007 t maintain fld capacity, because the trees in thse stream reaches are shwing the results f training, in that they are putting mre f their regrwth int canpy, and less int side and rtspruting. During their wrk, the CCCs crews remved large quantities f the txic invasive plant castr bean, and several stands f arund; all cuttings and seed heads frm these plants were transprted in cvered vehicles t an authrized dispsal area. The use f a cvered bed truck fr transprt was apprved by the CDFG in 2006 as an alternative t bagging; the cvered bed truck achieved the gal f preventing the spread f seeds while in transprt, while reducing the use f plastic and crew labr time.

9 Page 9 f 23 Figure 8. This stand f castr bean was remved by CCCs crews and transprted t a landfill. Fr an illustratin f 3 years f willw management, see Exhibit C. This series f phts taken frm 22 nd Street Bridge, slightly upstream f the castal zne, shws the cycle f trimming and regrwth frm 2004 thrugh 2007.

10 Page 10 f 23 II. The Big Picture As backgrund fr the selective vegetatin thinning prject prpsed fr the Arry Grande Creek fld cntrl channel fr summer/fall 2007, belw is a brief histry f agriculture, flding and develpment in the La Cienega Valley, and the Arry Grande Creek fld cntrl channel (Figure 9). Figure 9. Aerial pht shwing Arry Grande Creek, with Zne 1/1A Fld Cntrl District utlined in red. Agricultural Prductin La Ciénega Valley and the Arry Grande Valley have lng histries as ne f Califrnia s mst prductive agricultural regins because f the mild climate and rich sil. Bth valleys are farmed by families wh have been n the land fr generatins. Many are f Japanese descent, whse lands were preserved intact by their neighbrs when they were subject t internment during Wrld War II. This area cntinues t be an imprtant part f San Luis Obisp s ecnmy and heritage. Tday, agriculture in the Arry Grande Valley is generally intensive cmmercial prductin by experienced grwers, many f whm represent third- r even furth-generatin farming families. The mild climate allws fr year-rund prductin, with mst fields able t prduce up t 2 1/2 t 3 crps each year. In 1996 the fertile sils f the 2500 acre Arry Grande Valley yielded apprximately $10 millin in crp value. Arry Grande is a majr shipping pint fr brccli, Brussel spruts, celery, cabbage, endive, cabbage, lettuce, nins, peppers, spinach, squash, tmates, cherry tmates, and strawberries. A small prtin f the area is als ccupied by rchards, including bth avcads and walnuts. The Pism Ocean Vegetable Exchange ships mre than 3.75 millin bxes f prduce by truck each year. Cnstructin f the AG Creek Fld Cntrl Channel In the years leading up t the 1950 s, repeated severe flding frm Arry Grande Creek resulted in lsses t prime farmland. At the time, Arry Grande was a rural cmmunity f less than 5,000 residents. The Arry Grande Creek Fld Cntrl Prject, a jint USDA-Sil Cnservatin Service/Arry Grande RCD prject, was cmpleted in 1961 t prtect hmes and farmland in La Ciénega Valley. (These

11 Page 11 f 23 rganizatins are nw knwn as the USDA-Natural Resurces Cnservatin Service and the Castal San Luis RCD, respectively.) Figure 10. Arry Grande Creek fld cntrl channel shrtly after cnstructin. The main feature f the prject is a levee system (Figure 10) which cnstrains Arry Grande Creek frm its cnfluence with Ls Berrs Creek dwnstream t the Pacific Ocean. Runff frm Pism Lake, traveling thrugh Meadw Creek, enters Arry Grande Creek thrugh a pair f flap gates near the Pism Dunes State Vehicular Recreatin Area. The ttal length f the fld cntrl channel is 2.8 miles. Currently, the height f the levee wall averages 15 feet abve the bankful stream terrace, with an average width f sixty (66) feet between the levee tes. Maintenance f the prject is the respnsibility f the San Luis Obisp Cunty Fld Cntrl and Water Cnservatin District ( SLOCFCWCD ), under the purview f the Cunty Public Wrks Department. Landwners within the zne, called Zne 1/1A, are assessed fees t supprt the maintenance wrk. The Zne 1/1A Advisry Cmmittee is made up f agriculturalists and ther landwners within the zne, and has been meeting regularly since June Rapid Urbanizatin The natural features that make the Arry Grande Valley such an abundant agricultural area als make it desirable fr urban and suburban centers. American Farmland Trust identified the castal prtin f San Luis Obisp Cunty as an area with a large amunt f high quality farmland and a high rate f develpment (AFT, 2003). During the late 1990 s, 625 new hme sites were apprved in the City f Arry Grande in a perid f 5 years. This number represented an increase f almst 10% in a city with nly 6,750 husing units (US Census, 2000). This rapid urbanizatin puts develpment pressure n agricultural land cnversin. The current ppulatin f Arry Grande and Ocean alne ttals ver 35,000 (increased frm fewer than 5,000 in the entire valley in the 1950 s), with mre than 13,000 husehlds.

12 Page 12 f 23 AG Creek fld cntrl channel Figure 11. Prximity f residences and farmland t AG Creek fld cntrl channel. The grwth f residential husing in this area included establishment f mbile hme parks immediately adjacent t the nrth side f the AG Creek fld cntrl channel (Figure 11). These mbile hme parks currently prvide imprtant, and scarce, lw-cst husing t predminantly elderly and fixed-incme residents. Hwever, as part f Zne 1/1A, these cmmunities are at risk f flding shuld AG Creek vertp r breach its nrth levee. Envirnmental Prtectins In additin t being a USGS blue line stream, Arry Grande Creek and its lagn prvide habitat fr three federally listed aquatic species: Califrnia red-legged frg (Rana aurra draytnii), steelhead trut (Oncrhynchus mykiss), and (mre recently dcumented in the AG Creek lagn) the tidewater gby (Eucyclgbius newberry). Cnsequently, envirnmental prtectins prvided by the the Clean Water Act in 1972 and the Endangered Species Act in 1973 made maintenance f the channel t its riginal design specificatins much mre challenging. Renewed Fld Threats Much f the AG Creek watershed cnsists f steep and/r highly erdible sils (Sil Cnservatin Service 1984), and building cnstructin n these sils places them at greater ersin risk. When nt prperly prtected during cnstructin, r even fllwing natural events such as frest fires, sils left expsed during the rainy seasn have resulted in accelerated ersin and thus creek sedimentatin. Als, research in ther watersheds has fund that the increase in impermeable surfaces that accmpanies husing and business develpment, such as that seen in the AG Creek watershed, can cntribute significantly t a change in the watershed s fld hydrgraph, with flashier flws exacerbating streambed ersin. Depending n the dynamics f the particular watershed, the altered hydrgraph may als increase verall peak streamflws and fld risk (Bth and Jacksn 1997). The erded sediment frm events in the upper watershed eventually settles in the lwer reaches f AG Creek, raising the bed f the fld cntrl channel and reducing the channel s capacity t transprt water. The present cnfiguratin f the channel was state f the art when it was designed almst 50 years ag, but even befre recent urbanizatin f the watershed, the channel required peridic sediment remval t maintain its fld cntrl functin.

13 Page 13 f 23 Dense vegetatin grwth has als diminished channel capacity. As channel maintenance decreased in recent decades in respnse t changing regulatry requirements and budget challenges, the willws in the fld cntrl channel grew int a dense, cntinuus mass extending the length f the channel s bed and banks. The dense vegetatin increases the rughness cefficient (resistance t flw) f the creek, reduces the channel s verall capacity, and increases the risk f backwatering, debris jams and ptentially levee breaches, such as ccurred in 2001 (see belw). In the 1950 s, the AG Creek fld cntrl channel was designed t handle a 100-year strm, thencalculated t be 10,120 cubic feet per secnd (cfs). Hwever, in the past 50 years, knwledge f the watershed s hydrlgy has imprved and the perid f recrd fr rainfall gathered mre data, allwing fr imprved runff and strmflw calculatins. In additin, urbanizatin f the watershed has likely altered the creek s hydrgraph. Bth the 1999 Army Crps f Engineers reprt and 2006 Alternatives Study nw calculate the 100-year fld at mre than 19,200 cfs, almst twice the 1950 s estimate f 10,120 cfs (USACE 1999; SH&G 2006). As a result f the decreased channel capacity due t sedimentatin and vegetatin grwth, a 2001 US Army Crps f Engineers study estimated the system currently has 15% f its design capacity. In additin, with the revised predictins n strmflw events, the 2001 study predicted that the channel culd nly carry runff frm a 2-year t 5-year strmflw event; larger flws wuld cause flding (USACE 2001). The research dne fr the 2006 Alternatives Study cnfirmed these findings (SH&G 2006). The csts f carrying ut channel maintenance, including the cst f envirnmental review and permitting, have als prven a barrier t restring channel capacity. In a 1999 study, the Cunty f San Luis Obisp Engineering Department estimated that the cst f restring the channel t its riginal design t be $2.5 millin (Cunty f SLO 1999). The State Department f Water Resurces in 2005 estimated that restring and maintaining channel capacity ver the curse f 5 years wuld cst ver $5 millin (DWR 2004). In summary, accelerated upstream ersin ver past decades, and decreased channel maintenance due t increased csts and envirnmental regulatin, have resulted in accumulatin f sediment and dense vegetatin grwth in the fld cntrl channel. These factrs, cmbined with new data allwing mre accurate strmflw predictins, shw that the current channel capacity ffers prtectin fr n mre than a 5-year fld event, rather than the 100-year fld event fr which it was designed. Additinally, csts f perfrming channel maintenance have skyrcketed, creating budgetary barriers. All f these factrs cmbine t create a fld threat that endangers residents, businesses, and agricultural prductin. 2001: Levee breach leads t wide-scale flding On March 5, 2001, the levee system brke n the suth side during a mderately large strm event, flding hundreds f acres f farmland and several residences (Figure 12). Luckily, the nrthern levee did nt breach. Otherwise, the reginal wastewater treatment plant (lcatin shwn in Figure 13) that services the cmmunities f Arry Grande, Ocean and Grver Beach, and many mre residences and mbile hme parks wuld have been flded.

14 Page 14 f 23 Figure 12. Flding resulting frm April 2001 levee breach n AG Creek fld cntrl channel. Wastewater treatment plant AG Creek Fld Channel Figure 13. The pht abve shws the lcatin f the Suth San Luis Sanitatin Plant n the nrth side f the AG Creek fld cntrl channel during the 2001 fld. There is cncern that if the levee breached n the nrth side, instead f n the suth side as it did in 2001, that the wastewater treatment plant culd be flded.

15 Page 15 f 23 The damage t hundreds f acres f farmland, residences and businesses resulting frm the 2001 fld event led t claims against the SLOCFCWCD ttaling mre than $1 millin dllars. 2003: SLO Cunty vtes t relinquish Zne 1/1A fld cntrl channel t State Department f Water Resurces At its April 1, 2003 meeting, the Cunty Bard f Supervisrs, sitting as the San Luis Obisp Cunty Fld Cntrl and Water Cnservatin District (SLOCFCWCD), passed a Reslutin t Relinquish the Arry Grande and Ls Berrs Diversin Fld Cntrl Channels and Appurtenant Structures t the State f Califrnia. Cunty Public Wrks Department staff recmmended that maintenance respnsibilities be turned ver t the state Department f Water Resurces (DWR) because the SLOCFCWCD had nt been able t maintain the channel. The reasns fr inadequate maintenance included current regulatry requirements that limited the Cunty s ability t btain permits t restre riginal channel design capacity, and inadequate yearly revenue frm assessed landwners in the fld cntrl district t fund maintenance activities. Because f difficulty in adequately maintaining the channel, the Cunty was cncerned that future liability csts culd be ptentially significant. While DWR was mandated t accept this respnsibility under Water Cde Sectin 12878, the csts fr channel maintenance were required by the Water Cde t be brne slely by the apprximately 450 prperty wners in the maintenance area, r zne f special benefit, delineated by DWR (this area includes mst, but nt all, f Zne 1/1A). In 2005, DWR prvided a Statement f Necessary Wrk fr the fld cntrl channel, which included anticipated assessments fr Zne 1/1A landwners: under DWR, a residential prperty wner wh has been paying less than $10 per year t the Zne 1/1A fld cntrl district fr the past 50 years wuld we almst $850 the first year under DWR, and apprximately $1700 per year fr the next 5 years. 1 This wuld be a tremendus hardship t lcal residents, the majrity f whm are elderly and n limited incmes. There wuld be similar financial burdens impsed n the lcal small business, and there was cncern that the greatly increased csts culd frce farmers in the district t sell their land, thereby pening the pssibility f lsing extremely prductive agricultural land t develpment. In additin, under the Water Cde, DWR wuld be cnstrained in hw they culd manage the channel: they wuld be mandated t attempt t restre the channel t its riginal trapezidal design, with n flexibility t cnsider ther mre envirnmentally sensitive ptins. 2006: Lcal Prperty Owners Vte t Increase Assessments fr Fld Cntrl Channel Maintenance and Keep Lcal Cntrl; SLO Cunty Rescinds Relinquishment t DWR. When Zne 1/1A residents, farmers and business wners learned f the ptential fr ecnmically devastating increases in assessment fees if relinquishment t DWR went frward, they rganized t develp an alternative prpsal t the Cunty Bard f Supervisrs t maintain lcal cntrl f the fld channel. On June 14, 2005, the grup presented their prpsal t the Bard f Supervisrs, and the Bard vted unanimusly t request a ne-year delay in relinquishment t DWR t allw time fr the lcal grup t develp an alternative strategy fr managing the fld channel. 1 T view June 2005 DWR draft assessment fee schedule, g t:

16 Page 16 f 23 The Cunty and the Zne 1/1A Task Frce, cnsisting f Zne 1/1A prperty wners and stakehlder rganizatins, wrked tgether ver the ensuing mnths t rganize a Prpsitin 218 electin t raise sufficient funds t prvide a basic level f fld channel maintenance withut putting an ppressive financial burden n Zne 1/1A prperty wners. T determine the bundaries f the Prp 218 zne f benefit fr AG Creek fld channel, the Cunty hired a lcal engineering firm, Cannn Assciates, t prduce the required assessment engineer's reprt. The landwners identified in this reprt were mailed Prp 218 ballts in April When the returned ballts were cunted n June 8, 2006, the Prp 218 measure passed with mre than 89% f the vtes cast. Under this measure, the average residential hmewner will be assessed $390 annually, nt t increase by mre than 3% per year, and farmers and business wners will see their assessments raised similarly, generating a ttal annual assessment f $350,000. These mnies can nly be spent n activities within the fld cntrl channel which prvide direct fld prtectin benefits t Zne 1/1A landwners; by law, Prp 218 funds cannt be spent n prjects utside the zne f direct benefit. As a result f the verwhelming passage f the Prp 218 measure fr Zne 1/1A, n June 27, 2006, the Cunty Bard f Supervisrs, acting as the SLOCFCWCD, rescinded their 2003 reslutin t relinquish the fld channel t DWR. By keeping the maintenance respnsibility lcal, channel maintenance can be cnducted bth in a mre flexible and envirnmentally sensitive manner than wuld have been pssible under DWR. Fllwing Prp 218: Planning fr the Lng-Term The Arry Grande Creek Ersin, Sedimentatin and Flding Alternatives Study: Identifying the prblems and slutins In July 2003, the Califrnia Castal Cmmissin apprved a Castal Develpment Permit fr the SLOCFCWCD t perfrm sediment remval in the channel t imprve its fld carrying capacity (Permit Applicatin N ). The SLOCFCWCD had applied fr this permit prir t the vte t relinquish t DWR. A cnditin f the permit was that within 3 years f the sediment remval prject, the permittee wuld submit a cmprehensive analysis f the alternatives available t prtect public safety and existing develpment frm flds, accmpanied by a prpsed strategy and timeline fr implementatin f the least envirnmentally damaging feasible methd(s). Fifteen mnths later, in June 2004, the SLOCFCWCD apprved funding in the amunt $150,000 t the CSLRCD t cnduct an Arry Grande Creek watershed assessment and flding analysis. The Cunty grant was matched by $150,000 frm the State Castal Cnservancy, and augmented by $15,000 frm the State Dept f Parks and Recreatin Off-Highway Vehicles Divisin, fr a ttal f $315,000. The cnsulting firm f Swansn Hydrlgy and Gemrphlgy (SH&G) was cntracted by the CSLRCD t cnduct the study, and began wrk in February A Technical Advisry Team met with SH&G staff twice during 2005 t prvide feedback and recmmendatins regarding which ptins t cnsider fr analysis in the Alternatives Study, and t review preliminary results. The Technical Advisry Team cnsisted f representatives frm U.S. Fish and Wildlife, Califrnia Department f Fish and Game, the Castal Cnservancy, NOAA/NMFS, Reginal Water Quality Cntrl Bard, San Luis Obisp Cunty Public Wrks and Envirnmental Planning Departments, City f Arry Grande, Ocean Cmmunity Services District, Central Cast Salmn Enhancement, Zne 1/1A Advisry Cmmittee, and U.S. Army Crps f Engineers. The Arry Grande Creek Ersin, Sedimentatin and Flding Alternatives Study was cmpleted in January The Alternatives Study fcuses in-depth n ersin surces, sedimentatin and hydrlgy as they relate t recurring flding in the lwer reaches f the creek. In ding the analysis and develping the alternatives, SH&G drew n their successful experience in designing the San Lrenz River Management

17 Page 17 f 23 Plan, which includes an innvative vegetatin maintenance cmpnent. The wrk that went int the Alternatives Study included extensive and detailed cmputer mdeling, based n 2005 tpgraphic maps generated via high reslutin aerial phtgraphy, augmented by n-the-grund field surveys. HEC-RAS and HEC-HMS were used t predict the fld prtectin benefits f varius cmbinatins f management practices and prjects. The final study describes 6 different Alternatives, r sets f feasible prjects and management actins, that culd be implemented t manage flding in Zne 1/1A, and prvides estimates f the degree f fld prtectin affrded by each Alternative, as well as cst. The Study als discusses and analyzes the prjected benefits f necessary watershed-wide management activities, such as fldplain restratin, stream restratin, and sediment cntrl, t diminish fld risk. The Alternatives Study is cmplemented by the Arry Grande Creek Watershed Management Plan ( AGWMP ), cmpleted by Central Cast Salmn Enhancement (CCSE 2005). The AGWMP fcused n watershed characteristics primarily as they affect steelhead trut habitat. The AGWMP included tw substantial appendices which prvided stream survey data and habitat typing fr the AG Creek watershed, and an assessment f gemrphic and hydrlgic cnditins. This data prved useful in the watershed analysis fr the Alternatives Study, as well. In cmbinatin, the tw studies prvide a slid basis n which t plan prtectin f the Creek s natural resurces as well as successful lng-term management f sedimentatin and fld risk alng the fld cntrl channel. Develping a Plan fr Managing the Fld Cntrl Channel As described in the Update in Sectin I, nw that the Prpsitin 218 ballt measure has passed and will prvide funding fr a basic level f channel maintenance, the Cunty and the Zne 1/1A Task Frce are develping a lng-term management plan fr the channel and determining the necessary areas f envirnmental review. Memrandum f Understanding: Uniting watershed stakehlders t address upstream issues cntributing t fld risk As described in mre detail in the Update in Sectin I, watershed stakehlders are making a cmmitment t wrk tgether t benefit f the AG Creek watershed. The dcument which will be used t utline thse cmmitments is a Memrandum f Understanding ( MOU ); the final versin f which is prvided as Exhibit A.

18 Page 18 f 23 III. Prject Descriptin Selective vegetatin thinning in Arry Grande Creek fld cntrl channel, 2007 The Zne 1/1A Task Frce anticipates that it will take apprximately 3 mre years t cmplete the develpment f a lng-term management plan fr the AG Creek fld cntrl channel, cnduct envirnmental review, and btain permits frm the necessary agencies, including at a minimum the U.S. Fish and Wildlife Service, Califrnia Department f Fish and Game, Army Crps f Engineers, Califrnia Castal Cmmissin, NOAA/NMFS, SLO Cunty, and RWQCB. While the lng-term plan is being develped, reviewed and permitted, it is essential t cntinue t prvide as much fld prtectin as pssible t Zne 1/1A residents, farmers and businesses, while prtecting sensitive species and riparian habitat. Withut vegetatin management, based n cnditins in 2005, the Arry Grande Creek Ersin, Sedimentatin and Flding Alternatives Study (2006) determined that the AG Creek fld cntrl channel nly has capacity t handle, at mst, a 4.6-year strmflw event, r apprximately 2500 cubic feet per secnd with n freebard. Vegetatin management t reduce rughness increases channel capacity t the 7.3-year event, r apprximately 4000 cfs (SH&G 2006, table 3.13). While still meager fld prtectin as cmpared with the standard f 100- t 200-year fld prtectin generally cnsidered a minimum, the increased prtectin ffered t adjacent landwners by vegetatin management in the AG Creek fld channel is significant. T this end, the CSLRCD requests a Castal Develpment Permit Waiver t cnduct vegetatin management wrk in the Castal Zne prtin f the AG Creek fld cntrl channel during summer/fall f Under this prject prpsal, during the perid July 1 thrugh Octber 31, 2007, the CSLRCD, in cperatin with SLO Cunty and lcal residents and prperty wners, prpses t crdinate wrk t selectively trim willws within the bed and n the banks f the AG Creek fld cntrl channel (including the prtin f Ls Berrs Creek that lies within Zne 1/1A). This wrk wuld fllw the same prtcls used under the 2006 CDP Waiver. Infrmatin frm the Alternatives Study supprting vegetatin management T increase the fld cntrl channel s capacity t handle flws while preserving habitat fr sensitive species, the mst fundamental fld reductin tl recmmended by the 2006 Alternatives Study was vegetatin management: Maintain 10 ft vegetated buffer arund lw flw channel; remve remaining vegetatin; limb up vegetatin within buffer t encurage taller vegetatin verhanging the channel. This cmpnent is included in all six Alternatives presented in the Alternatives Study, and is part f the regular maintenance used in the San Lrenz River prject. This single management actin f vegetatin management wuld increase channel capacity frm 2500 cfs t 4000 cfs, r frm a 4.6-year maximum fld capacity t a 7.3-year maximum capacity (SH&G 2006, Table 3.13). We are prpsing a mdified, less intensive versin f this practice fr Prpsed Wrk Plan Because f the management histry f the AG Creek fld cntrl channel since cnstructin in 1961, there are n mature cttnwds, alders r sycamres within the channel. Hwever, during the past 3 years f limited vegetatin management, all yung cttnwds, sycamres and alders have been prtected, and there are nw quite a few that are feet tall (Figure 14).

19 Page 19 f 23 Figure 14. Yung cttnwds (fregrund) n inside f AG Creek levee bank, August All cttnwds, sycamres and alders are left in place during vegetatin management wrk; n the larger trees, the lwer branches are pruned t encurage grwth n the main trunk and upper canpy, and pen the lwer area fr fld flws. Nnetheless, the wdy vegetatin in the channel still largely cnsists f native willws, which resprut readily if the rt ball remains intact. We prpse the fllwing vegetatin management strategy, which is the same as that implemented in 2006, with n changes: Trees greater than 4 in diameter n the banks f the active channel, frm the te f the active stream channel uphill t a distance f 10 feet frm the channel, will have hrizntal branches trimmed t a height f nt mre than six feet frm grund level. If creek shade is prvided by adjacent larger trees, willw spruts less than 4 in diameter will be cut t within 6 f the grund. Trimming the trees n the banks in this manner will encurage grwth in the upper canpy f the trees, imprving their ability ver time t shade the creek, while als imprving channel capacity t handle high flws. Willws less than 6 diameter lcated n the levee banks and benches mre than 10 feet frm the active flw channel wuld be cut at r within 6 inches f grund level. Willws and ther trees 6 r greater in diameter will have hrizntal branches pruned t a height nt greater than 6 feet. N trees will be remved. All rt balls will be left intact t enable respruting. All vegetatin trimmings frm nn-invasive species wuld be remved frm the channel and chipped nsite and placed utside f the channel. Crews frm the Califrnia Cnservatin Crps wuld use hand tls such as pruning shears and chainsaws fueled with envirnmentally friendly, bidegradable ils t remve vegetatin. All invasive extic plant species shall be remved frm the prject site and dispsed f prperly. Large wdy material within the creek channel will be cut r ntched at 6-ft intervals and left in the channel t prvide wdy habitat that wuld break int smaller pieces shuld it becme jammed against bridge abutments. N heavy machinery will enter the channel. There shall be n use f Rde r ther herbicides in the riginal jurisdictin castal zne.

20 Page 20 f 23 All vehicles, including thse pulling the chippers, will remain n the rads n tp f the levees, and shall nt enter the channel. These prtcls are in cmpliance with Califrnia Department f Fish and Game 1602 Lake and Streambed Alteratin Agreement Number , dated 11/29/ Ratinale fr this apprach t vegetative thinning: Trimming the lwer branches n the trees within the 10 ft buffer area adjacent t the stream encurages the trees t put their grwth int the tps f the trees, thereby prviding mre effective shade fr the stream, and imprving habitat fr the steelhead trut. Fr any wrk cnducted prir t August 1, cnsidered t be the bird nesting perid, surveys fr nesting birds will be cnducted and buffer znes established arund nests in accrdance with the CDFG Streambed Alteratin Agreement In the area utside the 10-ft buffer, where willws less than 6 diameter will be pruned t within 6 inches f the grund, this will increase the channel capacity during the winter when flws are high, and when birds are nt nesting. In the spring, the rt balls prmptly and vigrusly resprut, restring availability f habitat during nesting seasn. This is demnstrated in phtgraphs taken f AG Creek fld cntrl channel vegetatin frm summer 2004 thrugh spring 2007, shwing lush regrwth fllwing the pruning and thinning (Exhibit C). When channel capacity is reduced, water is frced t a higher level in the channel, increasing the amunt f the channel that is disturbed. Currently, the channel has nly a 2-5 year fld capacity, meaning that it is likely t apprach vertpping the levee walls every 2-5 years. And during mst winters, water flws reach a depth f 6 feet r mre, and all vegetatin within that depth, where we are prpsing t prune, will be flded. This flding results in flushing f bird nests, beaver dams and ther materials t the cean. It is in the spring and summer, when water flws are lw and willws are regenerating, that vegetatin clse t the grund is available as habitat. If vegetatin in the Castal Zne is nt thinned, r if a wider brader buffer zne such as 15 feet is used, with n vegetatin t be thinned within that zne, that wuld mean that 30 feet, r nearly 50%, f the channel wuld nt have vegetatin thinned where the vegetatin is mst dense. This wuld seriusly cmprmise the effectiveness f this fld risk reductin effrt, nt nly in this stretch f the channel, but fr the entire reach f the fld cntrl channel, because this unthinned sectin wuld act as a bttleneck, slwing flws and backwatering the channel upstream, thereby increasing the risk f flding f upstream and adjacent farmland and residents. Endangered Species Prtectins Befre wrk begins, surveys cnsistent with prtcls established by the USFWS shall be cnducted t determine the presence f Califrnia red-legged frgs (RLF). Fr any wrk perfrmed during the perid July 1 August 1, 2007, surveys fr nesting birds will be cnducted prir t wrk by a qualified bilgist. If active nest are identified, buffer znes will be established in accrdance with prtcls described in the CDFG streambed alteratin agreement. On the first day f wrk, a qualified bilgist shall cnduct training sessins fr the CCCs crews t familiarize the crew members with identificatin f Califrnia RLF, their habitat, general 2 The riginal CDFG permit fr this prject was due n expire December 31, An applicatin fr extensin thrugh December 31, 2009 was submitted t the CDFG ffice n December 1, Per May 17 and May 25, 2007 telephne cnversatins with Julie Means, Senir Envirnmental Scientist, Fresn CDFG ffice, this extensin request is in the prcess f apprval by the CDFG, and written apprval will be frthcming shrtly. A cpy f the CDFG extensin apprval f the streambed alteratin agreement thrugh 2009 will be frwarded t the Castal Cmmissin upn receipt.

21 Prject Descriptin fr CDP applicatin 2007 Page 21 f 23 prvisins and prtectins affrded by the Endangered Species Act, measures implemented t prtect the RLF, and a review f prject bundaries. While the crews are engaged in thinning the vegetatin, a qualified bilgist 3 shall mnitr all activities by the crews within the fld cntrl channel. If Califrnia RLF are fund t be present, all wrk activities shall cease within 25 feet in any directin f the frg. There will be n handling r relcatin f RLFs. If the mnitr identifies ideal RLF vegetative habitat, the crew will be instructed t avid all wrk activity n r near that habitat. N weedwhackers will be used by crews, in rder t reduce the risk f harming red-legged frgs. We are prpsing a 25-ft buffer arund any Califrnia RLF because this prvides a 50-ft diameter area that prtects the frgs frm impacts, and has been apprved and is cnsistent with prtectins required by bth the USFWS and the CDFG. A 25-ft buffer is a well-established practice and prvides effective prtectin fr Califrnia RLF. Timeline: We prpse t cnduct vegetatin maintenance wrk between July 1 and Octber 31, All effrts will be made t cmplete the wrk as early as pssible, in rder t cmplete the prject prir t the nset f heavy rains and increased streamflws. Prject extent: The prject will include the prtin f the fld cntrl channel beginning apprximately ¼ mile upstream f the cnfluence with Meadw Creek at marker n Figure 15, r 0.15 miles belw Guitn s Crssing, and wrk upstream. Regarding the need fr wrk belw Guitn s crssing: The 0.15 mile stretch belw Guitn s crssing cntinues t be very cnstricted, as is shwn by the tpgraphic cntur lines n the aerial pht in Figure 14. This aerial pht and tp map were created based n high reslutin aerial phtgraphs taken in spring Seaward f that 0.15 mile pint (marker ), the channel widens. Fr that reasn, bth the NRCS engineer wrking with us n this prject, Susan Litteral, and the Swansn Hydrlgy and Gemrphlgy prject manager fr the Alternatives Study, Jhn Dvrsky, stated that vegetatin thinning t the 0.15 mile pint belw Guitn s crssing was imprtant, and dwnstream f that pint wrk is nt necessary. 3 The qualified bilgists used fr red-legged frg mnitring fr this prject include bth prfessinal envirnmental cnsultants and, when available, senir experienced members f the CCCs wh, in additin t years f experience n riparian prjects, have received specialized training frm USFWS-permitted bilgists, in accrdance with a prgram apprved by the USFWS Ventura Field Office, and which has been used extensively in prjects implemented thrugh the Mrr Bay Prject Clearwater Permit Crdinatin prgram.

22 Page 22 f 23 Sanitatin Plant Figure 15. Marker marks the area belw Guitn s crssing where the channel widens. Vegetatin thinning is prpsed upstream f marker , where the channel is mre cnstricted and prne t flding. While vegetatin wrk was perfrmed in this castal stretch f AG Creek under the 2005 and 2006 CDP Waivers, there were significant reaches that were left untuched either due t presence f red-legged frgs (this was true thrughut the length f the fld cntrl channel) r due t limited availability f wrk crews during the summer/fall fire seasn. Since vegetatin maintenance had nt been perfrmed in the Castal Zne since the mid-1990 s, this is where the willws are mst dense, and mst in need f maintenance s that the area des nt act as a bttleneck t the entire channel. RLF bilgical surveys under the prpsed wrk plan wuld be cnducted in these areas, and if red-legged frgs have relcated t different parts f the creek, then willws in the previusly unthinned areas can be pruned. IV. Summary f Request t the Castal Cmmissin: CDP Waiver fr Summer and Fall 2007 The CSLRCD, Cunty f San Luis Obisp, and the Zne 1/1A cmmunity share the values f the Castal Cmmissin: t manage the watershed in an envirnmentally sund manner, maintaining the natural resurces f AG Creek and its sensitive species, while prtecting the agricultural resurces, businesses and residential cmmunity immediately adjacent t the creek. With the June 2006 passage f the Prpsitin 218 measure fr AG Creek fld cntrl channel, the lcal cmmunity chse t retain lcal management f the fld cntrl channel, and has embarked n the prcess f develping a lng-term management plan fr the channel. In additin, stakehlders thrughut the AG Creek watershed are uniting t imprve watershed management practices and develp sund stream prtectin plicies, since many f the flding prblems f Zne 1/1A are inextricably linked t the management f land upstream. The stakehlders are wrking tgether t btain funding t implement fldplain restratin, stream restratin, and ersin preventin prjects thrughut the watershed. While planning fr the lng-term management f the AG Creek fld cntrl channel is underway, it is essential t perfrm at least a minimal level f fld channel maintenance t prtect the adjacent residents, farmers and business wners. Experience in perfrming similar levels f vegetatin management ver the past three years has demnstrated that the prgram has been successful in imprving the channel s capacity t handle high strm flws, while prtecting riparian and sensitive species habitat. We ask fr yur supprt f a Castal Develpment Permit Waiver fr the vegetatin management prgram described abve fr the AG Creek fld cntrl channel during the perid July 1 thrugh Octber 31, 2007.

23 Page 23 f 23 Literature Cited American Farmland Trust Website: Bth, D. and Jacksn, C.R Urbanizatin f Aquatic Systems Degradatin Threshlds, Strmwater Detentin, and the Limits f Mitigatin. Jurnal f the American Water Resurces Assciatin, Vl. 22, N. 5. Central Cast Salmn Enhancement Arry Grande Creek Watershed Management Plan. Prepared fr: the Califrnia Department f Fish and Game. Includes Appendix B: Gemrphic and Hydrlgic Cnditins Assessment and Appendix D: Stream Inventry Reprt. Available at: Department f Water Resurces Statement f the Department f Water Resurces Regarding Necessary Wrk t Meet Federal Maintenance Standards fr the Arry Grande Creek Fld Cntrl Prject Nw the Respnsibility f the San Luis Obisp Cunty Fld Cntrl and Water Cnservatin District, San Luis Obisp, Califrnia Exhibit C: Wrk Plan. Rischbieter, D Lwer Arry Grande Creek and Lagn Fishery and Aquatic Resurces Summary 2006 Mnitring Reprt: Ocean Dunes State Vehicular Recreatin Area, Pism Dunes State Reserve ( San Luis Obisp Cunty Engineering Department July Engineering Analysis t Date fr Arry Grande Creek and Ls Berrs Creek Duble Levees. Sil Cnservatin Service - USDA Sil Survey f San Luis Obisp Cunty, Califrnia. Swansn Hydrlgy & Gemrphlgy The Arry Grande Creek Ersin, Sedimentatin and Flding Alternatives Study. Prepared fr the Castal San Luis Resurce Cnservatin District. Available at: U.S. Army Crps f Engineers, Ls Angeles District HEC-RAS Mdeling fr Arry Grande Creek. San Luis Obisp Cunty, Califrnia. U.S. Army Crps f Engineers, Ls Angeles District Reprt n Hydrlgic Analysis f San Luis Obisp, Santa Rsa and Arry Grande Creeks. Discharge-Frequency Analysis. San Luis Obisp Cunty, Califrnia. U.S. Census