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HomeMy WebLinkAbout90-13C ENVIRONMENTAL DOCUMENTS GPA77777 77 777 77, q nd. The. tit st senil,en�e ender t a heaO "Butte y':re ;Department ol" states" of BCFD provides Structural f3xd protection, to all 'of, Butte County except :Zor thc� Ci,ty o = Chico, and the: E,1 S�edio b'ire District south; oir,'groV;ille This , statement is not '' correct, BCF'U does not px•avide firerOreCtiori iseY Vices to,tie 'Biggs Citi01Qf � e Paradise or Orovil,le.,idy,,' `S Second sentence" Under.:the heading, �� g Solid Waste r : nagzm16htl" states the followiri g: ...Landfill 'Co can accommodate approximately 3,225,000 -tons solid waste, is the ,of 3, 285,ppA tans remaining capacity, amount whi.Gh can be covered,daily; etc.., Sentence is vague. g' Q Postmti anon, CEA Conclusion shQttld refer to measure '5 2 rather than5. 1,. a-14 No :Fiscal analysis "•of, the cost to provide pQlaae protection "services at adequate levels of sexvioe is provided. No comparison of revenue levels W.11'prQjected. costs of services is provided. Mitigation measure is merely preparing a, Police Master Plan which does nQt clearly mitigate the identified .impacts. California Public Resources Code ,Section 15004`Subd. r .quit S envirnninental s review, .an, measures occur proposed m�itagat�on as early as feasible in thea planning praaess; Furthermore; the ealifornia Supreme Court in' Fullerton joint, Unified School D stri!Ct vs. of Education ruled. _that. all. environmental rv� ew Viand iiiitsgation measures must precede thedecision to approva the project. In the Chico Anneatiorisraject police protection. serV ces are. identa.fied l has ;haying signif caizt` impact: and require spec,xfic mitigation measiure"skh� . chi' r'e`duce such impacts "to a less than .signify cant' 1,eve1 to ! prepare a Police Master P1aii does "not provide specific; mitigation measures;a > This section ori Fire Protection does not,' address the impacts on ''the BCFD., if the CFU ,were to take over BCFU., stations wxthi n' , the ;annexation ; area has men, zoned in the text. There is no d'�.scussion given on how BCNU wcul cl: provide fire Pr'!corpora,, otectxon iservices to the un�ed population after turn�nq,.over� exis. t'ing�, f�r�e. stations the CFD It does not discuss Ross:ible re-loc cif f re; .casts.' stations r-or''Fb 5 16 Mitigation Meastare 5.6 a r. ruirentl �� ,ppear�Q }fie nac.equate as y presented. Th1 mitigation measure merely state°s financing;; mechanisms should' he adopted.t co.es. not suggest any specific fxnancan whether such f iinancih ' g `; mechanxs'ms nor sho g u1d be 'fee dr.tax ori;entecl,• T fee, whist' aut�ior ty dries the, c� t 'X .� ou1d Y orCoUh hi to levy a fee. how it ;be"establ�shed and what criteria should be utilized to determine fee costs.; x ` a tax, what. ?.authority ,does the city or count have to levy the tax hcata should: it Y ,be 'established slxou ld sorb tax; should. be­ a and how pPorti oned" 5 17 Mitigation. Measure 5.7 states the ado" tion o WastAl[anayement Klan'will, reduce impacts". If thePlaa xs adopted prior to a pproving the project such-'' a " miti'gat'ion measure may be applicable However, to,etat"e that the identified impacts will be mitigated b' propose n " a plan be Y developed does° not appear'ta, be adequate nor meet the requirements of cEQA, ;mitigat�,on measure .does not such a Ormod3 fications for ,the currents ONn spediti.c actionis "reduce impacts riot- o.ect to take to_ provide the; � oppartuni;ty to review publi with the the" mx'tigation m easure the adoption of 'the project. prior to 5-20 Law, Enforcement dzscL4r impacts" of the projection the Butted eouss cumulative Departure 't. Increased un"tY` Sheriff's cit. Y population Will require addztonaL services from the Sheriff s,ixch detention facil%t ices; JAI and' j"uvenile hall facilities, TYie Admznistrdt •re Drat does n6 revieca '8e how the project w.ij1 affect such services, 9--3 Third paragraph on thi's city residents �� page states "median income o should be Chan"ed t � 'median'hOusehold ibcomcs. 5 o "`' First paragraph stated'"1990 median;. famal 3nco $ 148n page '9--3 text sated +'meth a:n income cid cies residents, t' acid "median househala incomes.'" This is the. third may to 3escrzbe the same inoome fi" o Wi i.ch one, is it-? g re of Disc " ussion g of Hous,a n concluded a significant impart on houszn becau"se the proposed" h mss to" be. built in -the" anne�sed area, pail] no be affordable ' site the; 1proneked i'ljeat is" ,riot ,an be the. same; or more. 'due to the, acreage r q it is a :°old p1�us acre" per, hake in the CO6.11ht f one . Nitrate �lctlon '. Y jur',s:axct on due t6', the, ; an The Butte Coo of, GovernmPnt.'s Regional Hotisinq Allocation the overall 0 plan ca, Inco fo Urb a'n+, areato meet °' a affordable housing share; . o .within the' re `yor; not specify what, number of ' I affordable h using urxts must ; be l � bu3It i n:: sac . h nezghborhoocl • To deem the ' aririexation sa gnificant ' on th4 of unj,ustzfied fordable hoi�sang i5sL1e Se e I � I + I I V I r.: 1 7 1 i t ` I I . JONES &' SrOKES'ASS6o1AiES INC, 2600 VST SUITE .. 1110/SACRt�MENTO, CA 95818-1,914 a , I� I a , x, I x r� I I I V �J I I { I I I r I I I I h � � a I I , ij _, s � I�rYi , i, �.I`:' � '.�y,� .`, Y' Biu - ri 6,: ,• �� . f 1 11 t .r I r 1St of,F' 1 � S mare Page Watercourses in the Study;, area ... ;''.......... ;:.... ::. follows 2 2 Subbasins3sd int the my 'I Madel , ... ; ........: follars 6 3 > Comanche geek Computer , del F IW diagram , , . •..... , ... . , g ` 4 Butte Creek. Cnmputer Tvlodel Flow Dia aitz, ....... , ....„ . 5 Iltde Chinn Creek Computer 10` 6 ` Big,Chico Creek Computer Mod6l Flow Chart ,j .. ; . , : ll Oe.: , Lndo Channel Computer l~7aW Chart ...." .... S Mud Creek Computer Mode Flow f3iagrazn - _9 Projected Comanche%^gIydrograp. for, Existing Future Conditions, .....,... , ....... , . ; .':.:. ; .'.:.. ; .:. , ... s '23;' IQ CA Tattle Chico^ HydrUgrapf� for Existing and _TOO Future Conditions ..; ..:.....'.....::.. _........ ?,,4 . ...' ...:. 11 PrIp cted Big Chrco l lfy�dragraph for Existing land . `. uture Conditions .,. . , . '. ^..:., ....: .: I: ..., .�:.......... .:.:�S ' I2" Projected Yando Channel , ,., ragraph for Fxisun g and Future ditions Con26 I Pio acted l Mud'freek IAC dro a h far Exi ' J Y , gr , P Sung and �f ►„� ut_ ure Condi i it Ir �f I I I I t l i r 1 I I I i I I I I% �vT �i n t , J S1 ' A.JYStod I T�. Ab Ublle 1 Estianated 'Channel Capacity i Chico;., . , :.... •... , ... . i . '.. 5 , • 2 + o Mbu-& ` Watersheds in the Chiea Area i IIFI dralogic Model '• . ,.. , .., .. •, • . 0 .. • i . .. • ... •'' :.. • . • , ► . 14 I 3' Lind 1Use Categari"ens i�jse� in the. Chico �i drologic Y Madel • r r .'S v • • ♦ , • l i • • • . •.: • i : i •, • i'r e i r r • • i , r • • • • • i '•, 1i Sunulated Peak Flaws for .the co urea under 100-.ir ar. Rainfall Fvent10:,4 .. .. m.... ,.... ; ., ... ..: iv . 20Li 5 , Simulated Storm Volume I ea iiig the City ... , ,.. ,• . ...., :... „ 29 " I -� it r 7, �i rll I i I d,. I � I V io.l.� r I 1 I l I I"1 rl r i I 5 I i rn �r 7 P I I,. I, I , 1 I I I s I In � I I I iT 1 1 i � r 1 r� I 1 '9 I tt I' t l F �I 7 t $1. I� Ta, c5h iW,,g�pq `.eaf, i ,i Ofuyivd.$fo3Pm�` 'a� .C.7hico Utba�{ >n .P. w� R �. ra 3•,'I J !4 .'. � t, r' t ®/,� ..yv Y ,f v J -01 v -y1 Sr a Ml U,RI Orf u n� '� DIDVG1`1fQH Chico is located in tbe morthesteflq, portion of the Sacraments Valley, at..the fuse p?i the Siem; NP-va& Runom uiecyor he'nonflows au to deeks that„traverse ,the urban area. Starmwuter runoff at thnes has created flooding . Z.. c A d • - 1 tt n I e 4 . i:4r 1 Tf+ •.. pxobl'ems in the cit} and "the "agncul ural laid west of the' city. Flood control proje ., on _ wattle :Chien Creek,, Bag Chico Creek, and Undo Channel hays reduced the amount of water. r0, the foothills 'and "mountains that flows `thiou�Wth- city.,-` ., "The, wco larbanz axea is aymucture oY” open space and urban land ,uses. Some of'.the open space win ultimately be developed; "increasing `tai"e' amount 'of �xm 'cryio �s ,ground y . , ..g. , . 4 lPt ! r7 surface in the city. Changes rn the amount of ampeous azeas will result' in different S unoff,patterps ;, 'J s f a'� 1 G �; -�;va,� �.. �,},�.� ,��x� �.,� ;.!�,t�,., oto""ths;streaznchannel�ailks'; U much of the urban area, development lies extended thereb` settuiQ thet;matcunum channel size and cpac�tyi ° Vegetation: groyvth` �n the channel r d P oF" m i .J�.T �Y .Yr .,- >b''r.a{yl i° rA d 't v ,l` ♦S(, <'kt may reduce the"maximum conveyance. 'Thetefore as runoff` pattern s`and,quantZies change and thaniieldege'tation changes, the amount of runoff tributary o a channel and ?the capacity to convey the runoff will vary. Urbanization tray alter the peak rate of ninoff' and the total huff volume of a ;storm.; Peak runoff �s the, mai+ u�m flowk fair a particular storm that a stream would .have t.l.� m I ,°+, 7 it d `t � 7` f �+! a 7t I � N Sc � 1 +; � '6 4 �' 4 1�. .. .. torcomiey �Forr�arge storms, #be peakequal tliechannel capaty.f'peak:#low 1 :�, d �. 4� _.e t� t-�'h yk, 3S n' { •., ��"� r�� n ,�:' ♦ £.. , x.a `6`4 Ajil.,. increases because ``flf urbanize on,r' channel capacity could Abe exceeded d �u . ert�nore, We and, scour Vinay finer ,, +,.;, et zs ; ease as ..alt"flow anceasies r,, ±a, N;:,%a� �, a1 !.�,�{,. ,i�,i4(•., i i�rf�,lP��t E t,; fi ��{(�, r � `i' �.�. , � 4 volume? o runoff generate.{ ourm�,a stormlis unpnrtan4 because it may h6lidnce ,Ptsy�r;, t t rr !h 0 e i • r �� .-t .a laR.� 4�'tR it !'F61rv� �F�r ,i y 4kg1 +t �yC AT 1t . `.� I� y ( t a fl�aodang m� tbe. areas ,of they doer watershed ioeazn �.he Sacramento IuVer. Signui+cant r a w33 i .4g.;t aht'r frµd�F,j` � G �.�,_� ♦° .i`' n �, � dr., }���- t ry increases is total VOMMA *nary e},�and the Qare4 su=hjec to fl�dhg. oudittg near;°the oE� , w g� 4 rl p, ,rner„is anflu.�;dMby rrtszage and;; ossillyifro tle ur�han runofif.' ?9 � 6 � n.ck9 A �.a�n� 7 �� �i �� l��?k:F IY� nr��i6tafd d• r�4 m�-,�fr�� � � ��'; �., � �)�S C� �3kS :dim ,k ue �, ej� A1��'���Yt.# , `i , 7 °�j,,.al i a i r � J"I rt L��,W it 3 Z,ul ” ` r a 3,O I .a(,fi kti3fk Y S i.l i etthr �3 A x ;1 Butte Co tnty pgo .at t a _thetA%tiq Flog ia�s ranee' a n _. CYt of Chir„o does not` The loom flood floodplalns of several of t1ae: streamsx�haiyed foxpe IM. were: mapped for the ice. only those areas outside the Chico city Loins are included. an the florid i dsuratt; xna s' 4 " , r r W of s eery (Corps} a tjmated',#he ma t de,of e s dard The lU.. .. , 'gw protect plood and tail -year fla►od'for Butte; Creek, Bi Chico GYee Tattle Chico Creed, arid: .a S 1V�ud.Cree (U.S:f i�►rrtty,,Corps of,l��nguieers'Jig5F7,�1462).C`eFstandard. proaect'i�ood as the ;iarthat:migbitgbe ,expected iroaal tie,mostkaseverecaambivationofinetearola 'cal, and lo "e condia+�aistiat ark reasoriabl `chazaeteristic,of the'r a ` jh ' y . on. These stucUes cid=not _ provide co?mplete Y1�ydrog uplss,for a_ x lU4-year tloo� event � �',, . r Al �FlThe Crsrp,cctristrueted:floadoMrol projects on Yttle Chico Creek; Bid ChicoCree .indo;Chandel,.ndycamare�Creek. Terpect� dide;t`excess flopdvvater around Chico. 'She }ianAp cap acityl�of eachiproject is, suf6cient�to r�Dnvey�ihe �l�yea flood�,(T'able r 7 PM) tJ' 17 � `/� � 4 ,i .,fie 1teaent'studaes have suggested the lOQ-year peak fllawfar Big Cluca Creels above the druersian i 12,700 cub �c4feet,pera$cond (cfs) b sedtvon��st4t4pcal, analysis (An3srson 1474 Sas sited bg! Jones do il token ;Assaceates,'198;7). � bs ,figured„disk slightly less ,thau%pre ►pus estates). the;Ca ( � 'I � ;."ZI D o i��s`Ce,�`l�r,jaJt�u�rr -�zr.grk wl Purpose oftudv i 6 pp �'ei I PM dr 1r.:YvV C+ t9 i s'..c4e1�� �,� ?x,17 *ru.Tlus �tudy;pr�dvrds,a p%an,ievelamadelorassessing potential im a u p of buildout of the Chico 54T and providing sform; 5e�+rq gservice toG�the area, This analysis, i.� not intended to be a' detailed design of .draincge systems for individual' su, as m., The master plan should hetitsulted for recommended drainage facilities. y, Y'�ssL', Tibis"study coinRM of two hyd olog�c models, one re resentin ewstin conditions and P g. one epresentwg future conditions with the master plan unprovdnients in place. Changes fi w laffll=fii� ciet�ned ;based r� a' comparison ofrnof under e�sstwgl; aztd ,future contiteans.TusptYp of, differential coinpar�sonvoidsprgblems 4rolated to �iimodel, annum rK�ansbese►rb�as��sa�pped tato cases'6 F G tl fir ' f ",N 7 , "` i-1,.5 1,. � 'u a 1a x „y.l a 'a i �� t, H .�4t �,.:,� �pp �a 11 �:�fed,4iy iw',�11d.'. !� f �.+� 4� �' �'k � !y k � I'`i�' i'�n "a�r �A , ii t� 1 ' n M06�el MVE'.XQpIn@ntl)) 7 M -tee,. 1 V: `': ff Irk„ ,-. U tit ,r �r✓i it ,1 rw: w 1 J d r r v s unaif frQintrth n� urb area 3 ` e , a?� .was,svalulad using, the jlillwC computer model .adv�topedaby the Corpse"e nnoel,imulates runaf dor a gDven ralnfalll depth and pattern, �1}��j� q� }mac{.. .� qr a �. ri /.� g AstC�hVdM7Jf"ilaNFe,`M71.A{�,Vh41dWe� lO1Wa �lr�Myf JalfWi N ; ' x 7. p ,'' d' ¢' es., ii. I I i I r 1 I y , 77 thCroui'` Tliiis study estinesarinoff,t�wi� ghwor nearthd ci i'rom the t`r�liawiiv g"ma1. `or' : a�ntributing�./atr,;rsheds, .. _�: "X 'Wlj.). Mtte Creek; twrv�fs i bttleltw*coCreek, s. :big Chico Creek, _ ,® r.�ud.Creek,:and 1.0', the foothill aJnd east of fhe city►, ' As explained above, these creeks also receive water from tine urban area or contain diversion.lstructures that divert water to other, channels. The cbann`els 'siinulatedfiin the model, are: :Coomanche Creek; s -Tattle Oicol Creek,Aiversion vbannel 'Butte Creek, Ck h � Res AUttle ;Chico ,Creek, k1 .yik ■_ ig Clue Creek, ; ��' r Y Undo, Ch el, and ', "� ���, 4� Y� r , s Sycamore,Ge,�k,Averson Channel. The urtian area is divided Into, subbasins based on ,tine master''plan `culvert °aiap: lt3rban subbasins were defined based on' fife recerviiig water,-the existing.pipe network, xthe proposed network, and Land uses. ,because this is a .planning level model; Bubb' is ',were A ed to be large areas nescribed` by .typical runoff. coefficients. - Twenty subbasisis were ' - used, to describe the urban area: (Figure 2). Each subbasin. is characterized by average parameters that represent ground cover, drainage pipes;,.,e , mage channels,,and percentage of..imperv=�us area. These parameters represent ,average conditions that 'would influenceprocess o the -r 'ainfaU'ninioff f the subbasin,, They d© not represent a "specific condition at a specific location. 'Che master plan should ,be consulted for ,information: on u1'dividual 'pipes.. Ow Subbasins , Several -methodologies were,.used to sln,bhtexunoff iri;;the model: Tn,,the urban area Where streets and a drainage ,system - curb . and ditch), are 'present, gutter o roadside; , kinematic wave theo Was ,used to .'estimate. runoff 'he ry niavement of ;a �tlood represented by equations describing. momentum„and continuity of. mass, wave ,Kinematic theory approximates the rnomen r equation by asthat and pressure ,acceleration °fomes db not affect tlle,flood'wave The 'kinematic wave,assumptions are vaiid frr wide, shallow flood waves, such as tlase experienced with overland flow (sheet-flooding) t?ver- ...: land flow is common in urban. areas where water flows over pavement or open fields, before , enterin a watercourse or culvert g kinematic wave theo: describes the niovetnent of these, ry 4 Immow waves. :7777�., '1 1 urtxc �a�h«->•ameiu,u u�, eahw, i �� •NW.�w.fw..K. k9 S I Y i'.o , 1 1 ,� 9,CMCQ Gree k ' Wa'tershec�• I ' , ;; � ;. �jg �;IfkW w, , ,11• M�. Chico; Creekl � arogra,pb.,,...��:. ,rr I I _ Subb�sin 166 dy, Combe ";t • ", { , .. +.) s �'K gig t6oco k Creek µ Structure~ ` Route',Subbasi6 4r B19 Chico Creek n ftydrograph w , 0 11i CUAa/�{{• yh ... l Y i ry � I yl 4�� ok'Y1r T�YLlf Q``�+� { ill ��I•I.Yttl Ars...t YY'R. hf _ �� -+1 f ���M aI�JC M1I�,i�� rs� SIN 'U, f}(I QIc1CIUdit9g Routing) Y R t I ..� .1 k'A • _ lnk 'v (Includlen Ro ti ,g ..ung)`I 1Y i Subbastn 3 ydro re h I, � p T. ky� M 1 C Chi . C, r' � g eek Hydrogreph new S C �SacrAte�en ® • dwell A�r�nues I � I 1 w ' I I 1 .Iri G +ttM, uvi..arirn ^x+c� m...a1J,K IQf�b^U F a 6• �v BlO ��i1 Ico°Com I �, F hrysl 'C��pnputrµ , �� li%,i„uFYIYfflarkHt V.��k'�� W li"YA-i`! �- adel Flow Chi r't S�: , � I i• , r, � ,;, Ik yY t� �, 1 I . 7-7 77 fi'Y'e le :� Cin ith'b t Atcra+hc�ds an t�e� ?l Iso c, �hlyd 0 091 M.", 61; tr r, - �r1rv��� �✓di����:r9aw� rh) ",$iI�''h''I�t�'l"�4`$��'e�^a iib}�yi uGre.�,l'rv€.'�,,nti'� �"�'> .B7t.5 +i ' r.�; r, 'i. A ReCCDVin�{t� u94'c,h �'Co�itrabudtingl, t ti"F Catnb V WAtCtS WfitCr811eds�w`fi �VVIJ c 44,8,taSIf91S°+4�� { � h>f !,?t i1rlIlltfr e s _ n ai JS"^d& d d! "�N r{u, {1At °,Zti• r 9�a1)reWr CreC�fY 9 7 c t p ri Ld�FxF pxa7sA 1 .xQ w - � �cl Sts ;y�"$ S !4Y'l� d".�i �rx & i + r;�8 n + tx Draulager orlgmates m the SOI ♦ •f,, a4 r ft ChidO Y!1 +it Ica- # w7 '.as �S° j F..3 w rerislon IaEtle CWco Crcekf �4,� �'� "It, h' , � , Channej`' f L Fi „ a IMAO; ,r ,Drainage IS, OU 11e 50I E a 101,1a%t,103 1t%4;P �' � 4�':t a� €Y• wu yr yx ,.sr 1 g f � $utte Creels l � b F�!' °� �� r �,e (��1. �IPA'1 �F7;r U` � '' � u, .� d ✓� f2,21 � ���. att'�'`�-r '! ;��' � r dP �r uaYrir6ioa r i,>r, Cbanne� ..a,t� , x Butte Crecli { ^ e df 3, 7 r 'pit.. Dfelnag - otltde thel'SQI r 4� e i +�„ { :."i a iR 'a 1 } a {f � 7r Y cd CrC�'b 1/,50 HO, 15 C i6HOW,t�J WfJ1d�at:tUC ,Llt4fir J l A ' Creels bIV. raion ►S`tMetwe "t^x sf nhs� w+l. kjM .� ✓ti �L Big Chico creek BiB' CWco Creek , „y ads c 2�3f4,16� filow is divided at the Big Chico 'i r,i ;z in,� F n < A 105 . k'r' Py { '" n c a `iz rhe, 3 ,a B_,a$;iCWco Creep}C>rCO � DIYCrblon Structute �.aai10 ��'1lannel 7 kx 14►'s ,� didod aE the�Lwdo P,�..�t�f3�>�si'tJr ras M1 C s,�,�. �A� ,4a haunel{Dn�erslon�S e Sycamoie T�lverslan Big ;CWco Creek $, 9, 10,11, 12, y ReCelves llaw from file Linda Clbanuiel 106, ,109, 10t) 130j67 Channel Diversion' Structure Mud Creels Sycamore ay .� xrai�>p�a )Diversion Channel,: � ��a 6���� �� +. a �. g9 a .! 1 ]��` Yl, ar,•c,•u9W,P µ3 re„'fit �3v'� 6� kIC'3.,. w€, ,� d� J 7F a t.' ,y ,r•-.�. ✓S . r.�F+GC A�"�' l'a�f"rr'"4�'� F� � r. v1 �r � �p,:�,� ri ai '� �xr 1 � �s �i41i a! Y 4.1" u'k 'iw tiro IS Nry it , t 1 ('• k�d .a ^pzk � �1FTj�' wa, I,. �` F Node: SOT ,$p>r ucnce I: ,t q,� °s5(• here of tai0,�`' rk.f..9t {� A,, • ,..I rM1;k r, �, sA ufrd �! ¢r:.�l Jsl �:I r.•4 Y fR4. +'k 'I i 5 'r.�#ru".� a+,rQa�. - si �� 'raYlJ` t � .,�I�"�P >�, �"�.�� i ." !�-��"rrfh, � Y', 1,., ?ti�nng vrrsheds are watersheds outsl p°[Ilaafe 1111 rr } �u } de',the S gaged b+ the pro�erx k� P is ti s i 'zt t i s r, C11 a yr r4 �--drrixi r J�;. �i�a ° Contn'buting svbbaslns are areas inside tie SOI.that would change wltl project unplesnentaton C �i,�*�1F�rk J(� •,,y °�`i.}� N�jS iH �"Fe`,l }�•s.a.YG.1�',:�`.Fn 9+A. N'ut�lb,FF��1 fit} i as, .. d ii% ®tusule of•1 ve a developed as contributuugYfratersheds,but L tori ed to'samulate develQ hent •1d9 Yl 3+W�-.: t�t� KidDi y-1 PTAJ P ?1,. �+ V a 1 Py 1 A,i d 4 dl F r,•t d'z •, 1 "i. rrlk "Y i✓4 w .tit ifs, k OF UI1:f h,r zt tG" u, r z Al .�{C +5f i} {� , µ.. { a`av t}4. •rA" aw ,Yt 1:.nW ✓li.k�'„6 tfi,�,x� u.'�.—'.w,P J a I7, a , i v )F,3 MI , r� V gy pp r 9 I R ^'"YAr" ✓`l ^� 4 > d i Ff e.�h 6 J ~Y' ,� r PE�,�,. �+9n1 I i°'a¢ �� v'Irf t✓f»�,1?� '�'�` z`.�aSs "p r, n ro+W' ,9A 9 Ml k +ku�� �P: ri ,. I � y'.(' jy �t N y ',�r, r�. ” ,..,.. + €, ay5,: ,l wa,�Ti,.,�4�s .I awY.wA�,JL..�'rn.il. a� 1 :I r ,•� � i n 6MM } i4 U;f r pp 1 -, I� � �,�• .r� '�h i 1}"" . x'�'M1 �� f:�l'Rjr `i y i � i e Wi`4a„.I,t;Fix t��;�br+ I 1 $$ q 1 • f �.-V`k «.,,r.tflr,�sr.� wF xa ,«r P� (+�� )� � tl' 'Us%a'�k�4 #Y�4♦wS x%!''� U �,:�')i� r Fp,.;r r 1 ♦I �rc hn ',: ,,,4tr AF Xi lt'F4Wa,: n}�'if!s lit Ela r 1 '.€r`a rkr .rtia }LJ�tr�C,��jell Y-ailgas.+',rvfl'u'14„ C� ,�;y*-l.” rivda .1 N ,.. '• I I � ,I� � � X,� �'��� F Fk � "'r� t�r�$as �' w't �j��°�' ��.� ��s� l Ct.`t� r � •H 71eJG y .e I - I I I a I�h tri I I' A 01, 99 9M 10 1tboulit - ) , ryy}},, $jMils dlscu5sed la �j°��d#gni� abs , r `� t.� sig �t uen O ooniii'buUn to beds ��,�r3�� �M`'rnm the' hAl•te, :uW s.,�a�9 �.15htl off re reSBIlt a'l . i , ..-� p pAasng tbroul th�SCD 'Therp'f;....s4��� xnrc.napltaon��e �ddflfiw e, the moe eludesthese contnbii` 'vatei �' U iar:T ', l o�iE . .. f °} 1. U a r •,id..{f 31° °. y i Av,;N�" A -: N n !1 sk � .vi 7i '.' r„ v rJ�xt'd` Y% ,! ' L r -dor simhc�''r^ Tr"dtibfA'{�11t,`;�..�.i,eR" '''J '4 l�f':''i�> a -u,,;h a ,, -^yrs- .IrrR i,l M, 15 p Y the model considers eae coal3r�butiing�vc► rs+ ed a�gsty, e ` iA iif Bar with unifOrin jpEta o r1�4A •a fi. R do R�,� �.,Z �, a ea ' parameters: ,dor example; tae Dead Horse =Blau ratershed (ubasiitlS) contains, twoman-made lakes end contributes runoff `to Little Chico Creek near f-%gbway 99. The lakes probably delay or attenuate flooding t�lthougb these lakes influence file flow,of Dead Iroise Slough, .they were not incorporated into the simplified reprsentimnAro"f fiie :subbasin4 Usin sun lifted su y P., { bbasins for,the ,contributing area: provides a reasonable and fess rcomplex Itydroaph for the model. in adi 'T t>i'e` `g n +t kaon, se wat rs)iedsdo o °change ''•fa k, ii b�etweea the extsUng'and future condldons,Jand therefore identical assuin�'tions areaJ �. to both conditions. The. bydrograpbs estunaied by this techs.± ie are' tiot tende`d �to'be used for floodplain mapping or channel design. M/Y�rs� o Structures r dk;. ,. n t• I a d L, r t r,yq a•� s r l afT' 33iversion strictures bifurcate Little Chico and Big'Chico Creek floes k'lnta °five •v,f t,!{/�,d• f iii f +4 l,�h + } i°+ti7• v w 1T 8 1 1 +r - ! x channels:'+The capacaty of each structure and its inteiractaon witb°the other "s r "wife' eau I � rt �, { �rk} r -be estimatedfrom hydraulic capacity charts; The diversion relationships used 'in cher riael were based on the hydraulic capacity charts aril modified by actual flow data. it ,t _ Urban rSubbaslns ara s tn rt IT 1 £, vAd� fVa�RkIW xic},'1 4 ��tr n�F u a t%Lr � �w �M1 yThe 20 wean subfiasi 1 a I, ikd F ,.h'YN J a'air�r-fob �'i^dn3i •° were characterized Based _ng (rin the drama e -Si I r �, � • ryr II te_ LOirine�UOU } .master A i sate f p �,,i,, .,ll�k.aenal,=,potographs, and city laif �4�1 pazamr„ters re re ent w d F aan The subbasin . rt P a��rage ' conditions over the eittue,sulbas not site specific ylues,> ' 'he daainage pipeFan'd caannel sizes Wed' the}ino�el re resen ` , k i n p t aveirage� conciitldM in s4bbasm A A,r,, i r.<µx 'i ��M waw i� NO Y. �. �' 4'+..: rrJ IA 'rW { °nYa}m � ,i r I' �` # 7�rye"' 4gry,11e n ,�a16,'� I'pAr $�5ata I Soane rtions of the city! have incomplete drainage facilities or nane at"ail• �u;t.ermore, while drainages facilities tail discharge to receiving,waters during smallhstorms, ibis raay not be the casewhen tyle creeks, are full (such as Burin ama`or , mas er plan reco d tb . , g storm°event):' The - ..1 at>tle tissue / ofJ whether the rwater ,can reach the; streayn i5 , mny,pt� rtant;a id recommended'fiii leer s dy toy"answer:t1us''�' �`�Get.k,�$` ?(a r t M4fA ueJti�+Y s d. d r, "'f ,,,.� the iSSu _ ..wl�.,+r Q..sr 9: , ry �. toy aeS not as a buta rather assumes that tb r pwate`r,: cm flo .lire x Ik+; �/t� �az 9,1'k 1 +S I gyp,. 4 ww p�sr�r i a' f 41.1.1-Na 1 1� F'`Va. Ir Wc��in a g h 1Jlj•�/ fl(?adQ lt� p. use a k�.t v� d U 2fh1 iS -e 4dl ^ko f v 's a,d P a t �,.d s,.,�,�a rY�Pdr}i � �, ar' 1,',a' �I >Ca+P.;�� OnS Of't rrn. .ee, r �• M eurban pare : .q feed by made uat drain a facilities' esus a are se A h a off � ; l' . I g ,. , t . or none' at a11: uq some run flf�ndin a t an4� � �.�, ,�a fix; a i;a r a g t n ,t e� dsnU gll�°4lilg 5Oredilip�Alrily. ' lU L'ffeCt e incampletc,diaii�age,sysem is'madelecl uici"re'r T a <r ' , ,+�.� • �by asingbe asscimee,roiighness "of'the sarin area and -main culvert for each subbasii f fnr the �eiasting`eoiicliti`o �s int del: 'he, m,olc els' awned bi ws .the m ����.��:S,,�ghnss¢slo & oyeinent of water across,'the esu ` simtl`atin d ta�� k s' g:the ;r ru4CUlty a�wbuld ba ein�gettin Y+tame sgbll�lz. 1 aa.i �r7* r M ,. mode .�ak�,. I ..e� I dg m,�ouiiet , de -the suture conditions ! the oughiAess is reduced to a: value tb"a�Cr'eflec�s"a°ctual conditions, `I W I 15 I I r AJ ' , g� f . e y el s c toga • e. in� s��,,,�, ��,� �'����s� the subb�sin because rif made ua a drai,ua a �ttciUties { �, g g o ulat D In � v d� �'8i' . � re i,rR lye t + � r '>A. could be sim orlelin sma1 reservoir in f `� A 9" A • .� k �., 4aus. r €f n : `";� n g RAS: �. A .; { , . „ lle subaSiEl, BecatDSE:`°it 1S sUln that:Ad ,. a rt: I,gw,�ay r r {, a>S' ed. da begaviula�be at biiildout,''the future con ditions'model wotirld iiat d'"kPa'•Y.S a.kjt t�,A,i .fid i.uY s,}.., rl ilr,$ �'�"a".r 1'f.U� ti, �.i.�A �'�l�z'� w�','e contain these�reservous. Removing tlae res`ervair `f i3ffi''°a e` it adel` ould`uicre se`�the nombe �o ,dariabl"r-it, anged be and the existing and futuFe conditions models' which wauld uiCreF.r Mi', $t & 6 ar I ,,u �wr Y f k .,� e • h� V$rlr� ihty►�O the 1 SUMS t r ra Sid P u� ^xa r f ,t � �� �A'.y, a+ o s .0 u hh,,r1�"•, fd�d ft,r`rbT+4 �C,>nr r� °Da".� x�y Pic �lititl�' WQ{OS�d$ �nq t e� 7a ATr ,, C,Rru�tlfmd { 5 ir:IE Ott`11r �`� lt, r n :l IU.KtIyYS.ii i� 7 t'+ r�'z %dri tr p '.� I • i S 1 t S f fr �� i In deYeloping the existing conditions model, the stbbasins were defined'to represent txisting conditions and also t9 Perm.it easy adaptat#on 01;,ltie iii 9�1� MM�11 tore canitians"model. The a.Ya�m er.::7 + !'b1"{ • • U8 i ..f.I J 4 g i .i �� IL7 114117 GGY oaI off variables betweeiy `t,,e exlctin models y I. 6 and future ebb(�tia�i,S Subbasin roui! r� p' SCS curve number; watershed a timegand - by 'impervious cover,. cult' ,hn ss, the centa a of the ebb 0 m occu ped ghness area the only parameters c anged between this twa models (Appendix A},, Subb,asui rou ghness and culvert ijau�gbness ere used to sunultte delays in water moveiaient across the subbasui because' of the iwnconi3 ete t mina' a system""iin "" '' us ' �R „ g) pennousrea and S�Scurc�e'iiumbers simulated the land use• a Pd. TI rty �7}�� �5rr ` + d di � EI ,�.' 4. I:erid U s' se_ .. , S►16basin characteristics Word l '. • A {fl - 1 11 n h w. a estimated based on aerial photographs and site' visits: The*.per�;etage,Fof the subbasin that is unperviou�s is ane parameter that char es between f' the{ldstuagx aiidfutui' ' conditioiis;`''iiiodels. ssturiat s his` w >t • �Cyl n 4 T t r r 7 n . < �w f aC$ ' d`Yd at Ct Al • natfl T� , h ; � ,a, Parameter nine° land use ategonesNwere developed 6'abler3 `I'aese categonot relatu to this >Yiade�in� oali� and' ar r >� t 5 XA;P t 9 0+ ! ` i'�`' } F, r• f,i${k,i S.Nyit,K e:lg - J t. e` ;a not? intended 4ci relate to general pian and use dcsignaUons in Chico ' Anm ervious'/M►/�` i.. ,- r r,� I�wtWds „Ip 01ry �* i 4 di��yt~ ry+1, wp�".`,�. ,'` fit «�w �f .,t; T rr'Si'f F�, 4 �'>`I't 4,..: "'U't s +cAver ;. percentage.' was"assigned to each laud rise, and yhe subbasiYi s total impernous area estimated by determining, the laud uses in a subb f_A 6 ��+rP GI"', 7, r►r r"Ib .MIN wl mit rp^I p., d i. Nd oeft't `S �R �`; pDt r �;ta tru. Ise { a.� .d1,yj� yd ��+'r{pti. r rt (: sex �,r'' u r ' n t ` d„9N e.n V to § �'„L°F f N ✓`�^, a�a•ae I. ” P evelo ed the*auren s tl'su%vey ford� ,a ea'ni "' f�,IrNnu��, ,, >,„ .,rk9?,5nu dated star'ey is ui preparatjoxt but unavaila l'e:� `T'he s u .jar �� �`�`. p �� . �� r t al SSS sfaff`a "aiveld�ro' a soil types and thein runoff potential were,discilssed VVti x �� °, �. PPnae; curve, numbers, for the subbasu�s (Herrman Pers, comm•) The curve number estimates the runoff potential of'a soiI`tising four Irl classifications. All four SCS h ydrola `c soil classifi tion gr fkrtd sr t.l oups (A, �, aIC pCe111II te`5{ti°jam �u;'"I' 7 +t ,,., 7 , Iq; +_"'r r"r..�r�t1 ,N7+ M.. ,1< r' > aria . M . dy e , o estunat an a�rexage hydrologic soil classux n 'Stibb�r < r <b tra t y�iV'r oft ijq' t I P":,.9 <a t,�, 2, ,J .?', r' Sfi' 1�Sur, yca.UVn fax �rach ae iE *. a sul�basins were p icd o> ", 925 �st i L Sttry6 b and 'tll eaCh soil a floe six. �A r Vice y h a bbasiit was p ,+ w e percentage af" i I{ L r ra r r• 1 » ry✓§�$ adl I �,,.4 `= '4 � tin x.� we f�N Y '. ,�„D 4�w�� ai�4����1'Stl+ f• ��: rs �G�N k: hP-.,� 1 � :il it ?�!y ISa�As t � ! � 4tl T i +x �Y +r� M i c h e, ;, � ,,�tly�t b*?y' n A` 17 .4�. r•.; ,,yy,, y n .ads '. NSaI �p ,The a ✓iu$- 9 x mat t�cwave me.��dalpgyallpvts subuasm runoff toe'siinulatedtlfrom�utry overland flow planes. nithe'iChico �inodel, a eama't c White�rsba`d�s�4" W4simulated 'Using xik�xi:a °r`dl.t.ty�iP red 'F I`' t+ rb g' I 1 A r l 1, A '77777-, 7777 arie plane for pcavtoustsur%s pie for�amp�eIM us suffit'd �ach'plane has st icunte �p cumber reflectrg ranoft pateatal.�Z'he�ciiTi�e autiib�rfar tlefm erviaus lane re resents the;. .� fi r ; p p r, to be 9$ for allwaterhedsR: betvi► ; The curave� numheair'the tvi�u lane varied enASSumed ,p subbasu�s and was estunated from thevetghted ayes age soil type ��,end. A,, ASS` S !X 7 41uYi y, 9G1 ._.a a �,,j07 ,.. - 1 ,i The SCS cun►e number �me`thod used weighted curve numbers'to'estunate�wafershed a7unof£._The weighted`'eurve number^ft,r the subbasin.was-determined by considering the ' land uses in the subba.4, the average sail type- and the percentage of impervious area in' , each land use . Appendix A)�.,, ,�a� ��� 14,,, Canbration, An: Ymportant factor in developing any model is calibrating that model ,to meas: ured conditions.: Although DWIt collects flow data at seven stations. in the urban area, 'the coznplexit of the; interaction behveen channels suggests that additional stations'wold`have been helpful for calibration. The DWR streamflow;,gages on Butte Creek, Little Chaco :reek ;and its diversion channel, lBa9 Chico Creek, UP& Channel, Mud .Creek, and Creek; Diversion �5ycamore PChannelwereused or the model F� rel . IZawfall atterndafafron' erw erecahbratut niversity Tani sDe ' Sabla Sterlin:� 4G`i acidMin also used, Chico =1ty'FlArms: is located in the SOI while the other gages are located i ' the mountains east and north. The rainfall data were .often ,incomplete :and not representative of the St. "to ins, of February 1982, 1983, and 1986 and December 1983 were used in the calibratioiR... Best'' -fit estimates were: developed far the; four major ,contributing watersheds !Big Chico, Tattle Chico, , Utte, and.:Mud Creeks. An average condition was then.'selected from the results of the fow storms,: 'These estunates were in �' '` ,-. • - put into the model for the entire study area along vanth the recorded'�r900 and runoff from the De's>®ber 1983 storm. p'mai'adjustments were.'made to.the watershed paran�eeers based ©rt this stoi$i. ]Illitatl046, , 1'he model: developed, for simulating; runoff in Chico is coinple in the interaction of I ;the cgntnbutmg watersheds `arid subbasizs:; The ;complexity does not mean, however, :that. r ... y the results full reflect, the mtncacres of each subbasuL. The neo y del was developed to ;provide a tool to estunate potezatial unpacts Qf laud use ching es in the Clhteo urban area` for .:. , the EIIh. , , , , .. _r r w 7Cble 4 '4iimulate�'eakt►s' for the 0ii(. ►hdR yd r 10a-. - '}lear asnffall .leut x- ! J i'.dLiJ Op Coric��ons�*� Peak T' r n,e of Feat :Tune �- 'low'�$f'� y Pdik Flaw Peak Lavation (cfs) (firs� (al (°us) �1' A�y Comanche S1Abbasm,'1 ;{� �.: .420 1 0$3 B ubb i iF� t i �t.x v klnt�' Y�{r �' , r f, Oil `19 x .132 `� " 10S a , �� 3 " 205 ` Comanc�i'e Creek Y "` atfl�e�S'C)I x.0.'75' Little Chico eek Dfve�sion Cbaanel- j P, I.itile°Chico 666 watersbied' y 1591 7S n Pi,S.1 ' , Diversion charmiel y 4�2 ``' `34, 75 r ,c Subbasia`�101nsw ���7 ���� a+ 'o 10`7562 34:75 481$ + �':,U,�fis c 818' 1015 Subbase 'x0? , r r, ' X 958'' a �w +�� ! SubbaSin X03"t sr�sr ti?_r�r�,,Ci'i��t I �,�,,, 4K a fi13a00yJ� QS8Y 13:00 y� , 344 1 u (► J. 344 10 50` x' o . L�11'10Al �4 �SnbbasinN104s 87 q:G°�12.00�;4 `4875 b j p f F q p n Butte Creek��, a A�Q !.„�. ►�43 43.50 20;343 43,50 _ - Butte Creek at SOI � � - 20;5$1 43.50 20,581 43.50 I,ftte Chico. Creek Below diversion 1,129 4 75 1,1219 34.75 Subbasun 105 1 559 1175 /'4�,*,t it ,x/+14 �IIy �ka 1g59,�, p 1175 ttt a Chico Creek ya+adr Sibhal`sin"'105 comflow a��.y�Y,�4tx� J Subbasin 17 N s ���ti , 11.75 t ,�y4a y''i� ��+ 11.3 ,�� 1,,909 ,SllbbaS111 �, � l� # �t P�i� d�� �1 � (�J �2 �1v✓� � al 'L d� �1'W��c u,ti a ✓ i }���]y ^` 1 '' P �I 1"J }'� 10.5 Lttle W yre .G v.(1 a n a D M p Chico reek at SDI �,� �6a sr . `�ii �� �2 00'd, ��'�"21996 10.25 I u �I8 Cl�ficc� Cir+eek • V. ode x'%� A Eat 1 za n }8 CtvcoC�Ieelt waershe� ��9,;447Z,'�n W tz, , 4 Y � ,n�� R� �a� 393. X4.72 3975 Sbb�,. lII lU�S ' s • .�dl-- o� Cl r.. 6,•'ax+�J�-,' ;�r���� �'�+j�� �n"tij i'4 '9'4�,d �f r' 1 �1t e� r };fy11V���,r �9�9 Y ��76��� �1V�V '�r ;i �ixi i� , Bigaucd f�reekan b .. , !I 'x„, � fir ti 9 Y � Siibth fir 1 4 P ,1 06,combingd flog 39.?5+ , Cr I” x Ili � xY w i�x�n"� �' k:� F h 1i1 a 7 �„ i �y'6S' �f "f 9, 4 +a p x +•.i' w�q /• ar� (F�yxy'n�]• i JAM 1x047"' .��}} Y' • a fk ;ewlkiy �y�g r�' x. '�";y .�"� ` nem x# �np�� n t -R + 1,1Y°► / „ .'37.75�� uhbasia�l rr� r h'I wr p Y I f 1 41,{/��{_,♦�yN�fi,�� �1 ��s a �1�E.00 y 274 �11�pb , Bl$�� 4ew� i .Yi fiery^;n iA .:° f 1(Y ,.� J '�� t Vf� `rl f 'l n +:: t t b �x ail+ .+ ,,,t rl, r^ it I r � !/�►�■11 I�(�7�r� n` ��'.iR �.dryiyr y}j�/.r{'�")1 yj, �/ 'y4,n H �/j{C�{N rru. Irl�3+�i�/��,���J j�{ � A •. � n ` .:. �!t` {� �!e' ! :� . 5 i Y• 1 l,`Ti/ 4035 � ��Stibbasui 2 , , vt�' , 40.75x� `1,04 40 `�'5 Subbasin4 4 , 1,047 41.25 1,047 41'.5 ' 20' �rF ,y 1 I I, ti fl r e �� Cnnu�ed �: ~t�t�t1''�Sy xif RaA�Qu� 0 d+'i S4tialwyy ri 1i �'AP {I�V pc�:p�9i�,. �fp°8 �ndations Future Gonditic�ns - CYri�F r ty'na Tie of Pe�lc '1'i'�me of. It'eak �{ ; hFlow ha ' F10 ak Pe %atict'` i •,� - iViusi eek, 7,485;a 18,25 7,485 1825 x;.44' 93 , ; ..� €;1� 5 >.1 ; .50 112 14 75 Diversion 1, Muslj ek, 94' Subb-asis s 7 and`8 combeflow ,' r Ail r t � r t� Y 9 977 E ' 1 t 17:75 $9, 8 5ubbasin h� ,�7.7� 942 "' 10,25 �f ,, +, Subbasin z� r,fi 1, ` �, S6 Y>a� r> r, .K` ,1`,1,627 �10 15'. 341 dwiud CreFek- at Sol' r ` I « �_ � 1U 381 ; W ./�p(y� p..� }�}y�� 'c - Note. •L �J 1WQlii{9th n L7 ., �I /rip p ynp r{ISVrV. �YMY to tlJVl i �,f t .ih��i. +e5tern boundary of the sphere of mf(uence 06r Y, A. a �r✓� ��I �.�� °i - r� t qv [ i Y" W K , } t, a'�rir �rDOV it / � Rty1 ,�1 itlFl�tb r y , X' r a i �•`sr s'4.C. � P� l,rm tt Fv p Q [YQp t yyy[t C� v16 rs �Ytyr,µ. mufY kY.� J�yu a u. ? � n - r Ih f.d N,4$ l it 1 � r , 6 ♦ �'� n.� A'�Py p'La'fi lydP ' S 'y _ r � tlF,yi . X otr 1 2 � �" - � "� •,�, ' I � - d� °.._.:. a ';�'' s ."I i :.� "m '�;�o ^'j��m�lln I[ `�JEf�N•�b� rl l r1. � I I.' �uY� F�Y iL44A8Y {sir ' � '��4��k�Gtl �{`�4"'.``I�N� � yI r M t y� ���6��q}��y ��' 9f �,� I I 1 i��� �t' � ���` '�'' Yi }�„4. L to �•1'. � it �S�»YGF� 3��,Cn,. � .. 4r Xwv.'NM1>..i M r�r�2 ow 'cure . Praj��ted 'Co nch� Hydra raph for Pkc string end Future' nd�t ons ` I ,M' 1 �' -9 M fi� j^@7,1'y ��t� � � � � d 1 #--'�s��: ,�. I "1 � ♦1 + 1 0 r ^ I 1^ � I 0.9 � f. r 8 ci X77 r t fi ke yJ pba^ 0 r. 71 6 A O r` - i r i . 44 t r )I ol I 1l 1 r.. I i. I s,, w 6 p t TIA�EI sINcE srA p RTI OF RAINFALL E FISTING CQ DITIONS ; ' .(HQURS FUTURE CON[�IT;LO;NS, 'i All, "V y{ ,;. �+i.'�.3'.rt', '',$7-+rsW-�y� @ % k *," +ia#FfWC 9µ..',F�4>t oi,1 I pte: 0ea %ftle Chico Hydrograph for Fxasting and sutura (:ondi#inns 1 { 3:0 , 7ry GaCJ�. 4 ( I 1 I L�xi+ 'a M1: t$.w v� �PSiu.Mr✓<.v Iq .r. �ut �.". :.� �,1.. {�. tri JL,..%:� dG ..4'� w o G f. I r o.s �1 _ I GA r, 0 f 4 , 1 I A I I' 3 � 1 � 1 i 'I o .I .� fi� I` 1� .. . t TIM St l E iTART OF' RAI NF`gL O' EXISTING CONDITI(7NS + FUiURE C.ONDITI()NS I; I I ,: � 4 �$4..:}4y � t :. �� '� • �f 1�F , i q ., �. � i�. y,'� �.. Ml'i 1 � p •. Hyl - �4�rr p � �� .1l''v N' IP `+.t04;� h, li,N4 i'r� � {�1 5 k•�I�':l :�.�.A lii ':;Y 4:N''?� :.{p ll ?�� Ae:S Cs} 1 ?�'ll �}H .P �.1�, igjq �"^� Kl�; i'y$-/�{qp �4 ±1. y.l Mimi F;gze:ll. Projected Big fico i�ydra�raph far, Existing aid' Fut%re Canciitians d ' -Y �y O�. Com' J! �. I ��ryryrr-- 2 u r y I { p n �M-3 OJ 0 0 3 ®n; f7i� I fu {1�4� JI n �:nrkw.. fin+ /y C]0 ' I a,-” 0 � w... t✓w Ju..:na i41 I', 4vdlea au„z'z�, u � TIME SINCE?! START OF I 'AINFALI �HOI�RS) ji�0 E�'ISTING CONDITIONS FUTURE CONDITIONS uy �� �yM, Otto i , "��r s„ I, m ,fir d �` w' P gQ k" a= �� r yy�pp gg !! yy 5� p� ����yy �ry !qryy �}� gp� pp �y..y+ ,,�.,. Ux".!i,+,`wLi""v l��F�',a aq%A1C'� ;b.'ttsgvf �M i� i�xk MA :05v°Y+l,W (W To '4 u" V +'3 q w, JV 16 iA +! r� k+u j � SY r I ,Figure; 12, Projected Indo Ctraune l �Iyaeagraph ,for iExistng and Future Conditions i, iAI r ,f •1,' � r f, u 'Z'" 1:0 ,x•• h a { '0 1201 Pz 0 ! 0."5 I I f"i. fie, i ,Yy xi i ryy 2— w. .-�•�.�o�.,o4 �.,� 2+N 8a: so . 1 .��.�<Y <�S� A�s,.'�,..,. AJH e�M Nv r SrM .5 �)N nn M TIM SI'NOE' START P :RAI NFALL, ( H0URS) X' ISTNNG 'C,0 DITI0 S',�FUTUaE CONDITIONS i yT� tt 3Ft p 1 TbW �"y, "JTrQ ImA',' � rt 4 ON Figure 13 Projected= IViuO0 A Y ycDrovaph for Existing and Futt�rc audit ons 76 M C.�`�.7 °', I P-3 wa r fi 9, f r 9's % s4 9 . J F 1 �:y g s � ,+ i. 9 s -�" C 4 f V'�t F t:.;: ! k { ..3 'r d• I A } 1n L �, �.. .pe,ftw ("4rer� su t K � a r r ; '•.f� �: r�,',',.. +�? k .b f Y { k'r _ q t ' '{:, f'�:' � "�� r �7: r . x Ar 1{r '!a '� t r r ° t , .• a'', r y :_ w u+ tlf.�('.� � 10r0 t 4r<I " a b" rA ti F ' tt Nrer r G r eft �r 9t0� r , 44� :. ,� °E} •,;.: �,� ".,.,; { t� �t L>. t � �a` �7 Y� - !� so- ar '�� �f� �"�'� � -� •,}P�Ph�, r Inz � r4 b rh (.• 4 .a x_ 1 rt ^ u'1.r I dru 7.0 rx^ r,f u Y, a f nip [ r«�3 p t ,a ° 1 -''i'p ��":i KxJ L1 w '•4'� s k i,` ' "p'F E raid 41y' rt 7,,: M ' s �u *• L',a r L:.' ,ti in an=p +�•�' �,u %° u,ry Y k r% .. 1..:�. .., 6ra.,9 T :✓ r 3r ' a '�° k3.�i i STsr A;j L, x 7 6.0 'F r r t rx � 'r �U 3;,4':7 : ,"✓ 9�3 ra" aw +•a _ .k{? i r s �,. •I x �r '4. { t r.. t dj' { a Pir+". ''Y +�•.aV .w Y; :yr m.k C o�, c. t`.'.. 'd6Y 'y,.;. r-rJ 3p.;7:, .J:O i_v j •�.,. u�a$ w>] k. Vl> >..� " "y )1 7 ��r.• 'e'",° 1,wt ri 0 �.aa nrrT .'Sr '�itt* u. 4 1 "i nwar 'iY �i 0 ' '% }: *-"° ,F:Q } �<'� fj k'i 1 Y r t J 1 ,A1 h •,ur �.c.� ! ^ ' �'• ti, }.ryro A ` J.:. r tr :g„ LL r i y� z.. °..:. 7 . p"�40' i.lt r,. x i. V, t A, -.� . ,_iL� ..s>.;'•.;Y" :.-.._ .::� 4 i�.::... ...r:.. '�• S;. x„'rr;:_ �r _;' 1 ..' � r 1',�+ �. '"": E' `i r: �' :.s:� .-a x? LIG�..�.-.�.,.. + y �� 10_' Az.,N w"'N to .r ^1}w <ee ' t Our � + .p � 9 i,t $(;a a*y .: iia'•'' Y)±:. �Y�' x: P' :. _. '' q� E -.�. :.. :: r„n :Yr ^a "' 9,*^ �,�' ;:: s - ,•.a's w''s •, ,,,., k,,.�+ :'. {xt. t,x; �•� ..P t�'� _tir� x :�`:h r+i;; "r � „...;,r 5 Ir i"I �„ 0.. 4,1j'2 �' P + .0 .. a;�' .� � i �`."..; i.: .,, ..r w.�ro"4 e k. , �r I�� �4,5 b,•w. „.. n A� 9` �x r p 9 r:y'r ,{'d: r'., 1w, , '.;'�.: .a t ,,. td •rr.: rrr:: a I.-tY;:;:' rr.>♦ .Y!::..w rH' t • �'o• 8.r.f ' Il:.rrS- rl .7..;�. Cur+:-. ;" auk " :. !,y' 'P,k4• ,_" �� ..'i,, -19:J Frt a ;y ,' ,.�'arti �. 49, ��. wlr iicD , M.ir na"' ;.n ._ $$ �'• «_ ¢ ry1M.=,I' w t. 4,N >« l a', ! •r' a;,`� ' i� 9s ;....:+�a iC.. 4:u1H ^trda^' "'' s*�E n1 - ,..,�,x r n 1 ,r a. {it':..ft>s '1�`". r ?Ih- , ", e 4,0 a;rt r .�5 19l 1'. N.n 'a' Koe �{ "n, a 1' r d u a tea, i, 9 ,,"�:: �� 4�,: vii ;r xi" r `* te• �, �* , r., � w <asrx '�� �'�''',�;ta,� T ,"n ��, i.,r '� ,?� Mri� t ,�,w ha,� : 'I r $ 3'...r'y*: k'r 'f tf ti r r 4 3 ,M :•r ;.ar 4, a3p{ .n.„..Py-.'..:,x.. r,aA. ida«i�+.' � 3 , `r, 0'. , �, ,1. r.': . '' faas»Jn.7, � sfnutr ..,,.9 , "v .K e._a•. !t;�.`.. ka '+"u'I�+ti r'�,-�> x 1��w "� 5t.r-"i'i,e.0.'.,, 7Md�tiYii-���'q° _ ..,H, S r�xir,k.,- yy B 0 ,P `'... 171•�r f'. a 66a 4-b .op.. 8 � i. n' L"`a u a m."rw• 1" �� ''r` , �1 � �." ,7 rLr"',k r. ! ..lwr, kl+l 'S k P.) }apt .°.: R; �4, 1'. �„ STARTS0 R P I. ALI. (iHQU ) ;� _� w, xr, ,11TI Vt sol A 1d,EXISTING CONDITION - UTURE ,CONDITIONS°; ; r ' r " 3 .. .y 7777777777= 7 7 1 increases, contributing additional flow to thy, ead lH[o�se results ion a higher Lattle..Cluco �� Sloughhydrograph:�Beak. ''Y1us Creek peak flgw,) uder,future,cond tions than under exasting conditions.. iviodeling the Dead ITorse Slough watershed,!including the lakes; +ould' delay the. bead :.Florse Slough pew thaw,, andierhaps' it would not eoinc�de with. the urbAa peak flow,. thus reducuig".the effe+-t ", the urban area. The model results were compared to channel capacity estunates from a previous" study (Table 1) (US Aria Corps of Engineers 1962 . } The simulated.add tional runoff.from urbanization is not projected to encroach on. channel ca aei p. ty'through the city except in Little Chico Creep where the pea.! flow under both ,existing !and future conditions exceeds 21200 cfs. This peak flow is influenced by the simulated' bead giorse Slou h "dro a .h and Y gr ,p "the assxunptions Iregar, g ti a lakes: Refining the ,simulation of Dead Morse S,crugbi to include die lakes could delay: the flood hydrographs so" that i' would not be coincident ;. with ;the :urban ninaffl thus reducing the ;urban flow-influeac d peak. The Comanche Creek hydrograph, which receives runoff only from the urban area, , i8 the anlr simulated hydroggaph at° the western; edge of "the. city that responds .completely ito urban runoffe, Comanche Creek a eneinces an Iuicr 'eased in peak flow ex - ' from, X4$5 to 1184 .cisfl between existing and future conditions. This"increase is attributable to the urbanizatir�n of the southea§tern parti9n of the SOf : '�' r kU in generat the changes betweem existing' and future conditions r"esult in increased flow over ;a of the hydrogi-a for portion eachkof the water courses modeled. The incr ease r ■ occurs around the peak rainfall period, 10.12 hours after the start of'rainfall (Table 4). ; ?' 4 G 7 d Y �:. co y Flan' u. nth the-Master"': , ,. $ lbelli master plan estimated peak flows for future conditions under 5 "and 10-year 14 return- period 'storms: "Peak flows c;stimated m. the master plan wer"e caleulate, using the k rational miethod. Watershed ;C in the master plan had ;a 10-year peak flow of 76 Subbasin'6 oi'this! study compares 4o the anaster plan's watershed .0 and bas'an es`tinated, peak flow for future conditions of 1,627 el9. f r z �'atersheds A and E ° o �, P : , f the master lar :are similar to Subbasin 5 of this° study; �1 "'Vatersheds'w and B have a combined'" peak rflow of` about 370 `cls; Subbasin 5 has a simulated peak tlow °of 938 efs':a �1 Y2 °I - Ruaioff Volume cl eased on runoff mul siations, ;the change; in,,,,dotal runoff volume leaving the SOT` between, existing and future cauditians is snctall; "Comanche Creek is an excep'llticiii. (Table S}. The srnFill chan$e fad, the' major" creeks is r`olated'fo` tti'e purge Xolume' of water entenii the. 4; d ,6 .. fr city om the confit ibut an$r tersbeds.a, Commanchei Creek dAes mot have sucbi anoutside influence. � Jb . , v* 4�i The ;urbanization of the Sol w, l increase the: volume of runoff, leaving the 01 to ab16,S . Tbc ugtcrease hn volurt the vrest�(T M ) 'f er ranges from�4%oto l6% of the existing urban runoff for�,the, majox,4watersheds�F ;'T'he o ache Cope C 100 -yeah storms volume, which 'ves =off onIV from 1lhe urban area, 'is grojected`,to Win crease by 22%: ,i Flood Mage n . The sunulated incrO se Wi discharge' m Little Chico Creek resulting from urbanization (from 1,256 to x,996 cfs) waWd result in about a 1.14bot rise in the water« surface (from_ 6 9.: ;' to g:0 foot depth). At, the >:iownstream ed&,4o64 Subbasm 1the simulation1pom for'tlais pieak: flow, the channel r epth i.� significantly greater than' `7 'feet. More importantly, the -challool contains dense vpIlet fon, 'which ,retards flow and,"'nfluences flood de th. The P ' ve etataon ' p % � el. g �s resent on the, chaumel, banks and leans out into the chane Abe::effect of chsi,incil vee elation oar flo`oci depth is, dennonstrated .b cam Grin ft tie g P y P flood depth,,;sad:- a given discharge for different; densities o,, ,channel vegetations For' the existing couclitions dischargc (,25�6 cfs) ane toughness (assumed to'be 0.05), the_ ed - projected, "flood depth is 6.9 feet basery on Mannings equation. If the channel were ., cleared, decreasing the raughne;ss tc�F q(135, theaflood depthvould�decraseto S:6 feet. If vegetation were:allowed to increase to levels smular to portions of Big Cluod Creek `or `Comanche Creek (assuimd Pouglines70`0'. ic flood depth would increase'to 8.'9' feet. The effect of the current channel veF;etation density on flood depth is slightly;greater=fhan the effect' of increasing discharge frorn existing, to future conditions;: Comanche Creek, has dense vegetation at various locations along AhO channel. The 7 simulated discharge for Esxisting canoitions would restilt in a flood depth. of about 6.4 feet 1 at subbasin 19. .Under, Buildout conditions, the `depth would increase bto about 10:0- feet- Red� ring the yiege'tation tri Comanche Creek to achieve a a toughness oi-` bout 0 035 would. ;decrease the fload depth under future conditions to about 6:6 feet: ! I !, I r I I k J , f. 30 1 I (( I It i t i pp I r S ii r u. ,< C�ontuaued ^ ). yyi�dd y5q a^mak ' e^ hi��'+±p1Ut4S5Y1 � 6W;_.l1� •x „+dam +.��x' Length Sl S%bbasia� ape ouch- mea � Botto ]t Side U stream R, O f MY, ft �w • Hess (sq.tru.) Supe' Widths Slopes lnflow ,',� x S100basin 18 I Collectora 7,100. ��QO20 IV in channel l ,Osp'�'"�' .31 Trap x,5.00 .U8 'p 2,46 ; 2 Surb%stn 19 i�pllcctor 400 10020 .015" U17 CY�c 2 M[aiu channel Trar. .. 6;500 :0033' /gyp X0$0 -�. . 111; w r, m .3;5 P Sfibbotw '16L Collector 1�Iam channel 24400 .003;1 .OSifi° 2.36' Trapmoo° I • Note., -- = indicates riot as plicahie. � r y � I r 1rcircular'Ire,conduct.+I� 'Trap trapezoidalcharm I "'Thle hottorn W. l a c rcvlar coriduit'is`the d(IA ' ,fhr d%meter: U 4ry� Fa r �� 1 ✓� � - I ! I 'G It , I , f h P 1 N• I , xa d _r•Y �64,V 1 '7 � .l I � 'Id J' - {• 'i. f N her I I �t Y4 �N 1 � � 4 �6 •i ,� � 4 f I I s- ✓ Yk i� J MIA4YY.i }.�•W, Fel a 1br^4 'l Yi}i!t" ih }^W Fy. �I I; I k°�t1' �^aayy� JjQ� ry.I' p +� d�i��lYV'ilri+�y�'`N'af I s '� �:� + ��.. n r � _j� Its o =q r >ysM_Sha'a-arY tilaa+u v,.d•el ,M�,�rvtrn +.'.� �{qY -�+K-:.+M+Y.+ ,.�+wt-..e»r�y�''1 I,r w M rr gra,• fix m ..B �x � s ,., ri� -t»�x,_ sl I;i+ I I I !� U Y f I i I j 4 i t. s X t - - 10 'i 0,4qlOgy As suMP'U M it r4 d"Id Its : W.116 ........... I R U I-0 tn' � dbbMiri' "or N*� hours Subbtslp 3 QA6,-,.. '71 �P it j%., 4 Sfibbadgl 2 4 .50bas .0 '84; am Subb7 S�ibbasn 11. a'.A tj 'Oi IS 70 01 Su,�bgl'fmn, 12'. $61 m :Subbas16 108 jr 133 `18. Subba�sin 101 3:85 184"' Subbasus 103 0.36 , y- 1 01 asin 0i, Subb: i 1.67 84: nt 1.95 as 86b iia'' I Awr�j %�IkJ X W'!- 1 4; SubbaS4 4" SZ, 0 lza 41 Ii Oin Ii4 Stibbas' 0.86 84. 1.98'. , asm 0.9 "84, :2: u asin-110�- 5.54 83 35, little Chico C 47' '16 5 1.5/.07n:, 295 'Big Chico"'.'Prep k �'I 6/66 m These watersheds use anim i OSS,ra e inslpiifiq, number., ' '-'d 61 and t 1 ''t d f Thes'dat;L��C64$tah a ;irp: listed as IWO loss/constant loss. TV curve Ji Table; fir► S: outing Reach Assiut `ions Ps�� w. Ri r:� .� I� �rn� i�n�laryrynN f .�jtttFyk� ✓L]d�IN M4r,130,4�'�d �� Y!.�Y�.4��'�� u`tfire iq ar h ndit yy�� **u {�Ij��rnl��.'>i tA��d Y�M1,N 7 1 {^�..,.� I: LLS.�e���� f _ } I ^ pp �, HI::A ! 1,-.C.� _. k...><.. x�iF YK I141�. 4'i.,,. *'z hHQ TS?W k..�'„-q �. WC.'k�-%.�.� 1 K �`•i�'43:LI,MnM 'z' HF YRQ'1lX.^^.. M1Wh • , Mope' g�K{ Bottom Wfdt� Sidef � End f1 ) ss shaPa SlopStart`, es )f ,Nfo4b ll,l J, r u Sub X13 Sub 14 4 2,000 _ .# t IM'Ir u'i:��f^� ta>-f.`. .0025 x .080 „Trap x .. 3.eW c�..:. 30 2:0 L- cc, Butte Cr.. X3,400 ;0034 .035 Trap ° 35 3.0 Butte Cr. LCUC lit ,. 25;300 x0043 .OSO SO ;t.0 LGA Dam DHS k 9,600 ., '006 5 „NTrap .070 Trap 50 a.0 I DH S LCC 3,900 ', :0038..070'` ,, ,Trap -3 Z.O Dam 10,000 ,.0030 YI, .050 Trap �35 5 BCt Dia Sub 2, ,r �19,40p 131 .0801Y"rap 35, L.S Sub 3� Sub 41 3;500 00031 080 „ 1ra Sub 1.4 Sub 5�" 8,200 .0052 080 Trap 45,0 SCLC Dara Sub 107 ,'I 9' 300 0043 .035 � Trap 140 t.0 Sllh"I47 Sub 11�J91, h 8;700 UU69 .0351, .,7Crap 100,�?.0 . 5ub_109 Sub 13. , 3 900 .0005 :035 , r1"rap 10:0 ' 0 '811. b, 13 ,;,x Sub $ 3,000 ;:OOHS .035�,Trap 200 tFR SubII 1VIud Cr. ,J 5,900 0005 .035 �T ap r 200 . 0 T�tud Cr: Sub 20 {' a 14 0024 :0350 150 Z.O y {.,Mt 4 xi. I i 1, W n�'• . 1 r r� s, otess' Sub —subbasin. Lit11e `Chi o.'Creek.t., — . I.attle.t+Chico I?averslortYCitannel I lW r DHS 1Dea ,Horge 816 'b Big°Cco �:reek;� "S 'eft Creekiversr�n r<See xx4odel oututY('Table A.9j fomr:Yacatian of roii}ting reaches ut+ ie mod�1: , l� I :4A 'd .W� F!, I 1 I � a I I tial � I II I t