Utah State University DigitalCommons@USU All U.S. Government Documents (Utah Regional U.S. Government Documents (Utah Regional Depository) Depository) 1994 Flood Insurance Study, City of South Jordan, Utah, Salt Lake County Federal Emergency Management Agency Follow this and additional works at: https://digitalcommons.usu.edu/govdocs Part of the Other Earth Sciences Commons Recommended Citation Federal Emergency Management Agency, "Flood Insurance Study, City of South Jordan, Utah, Salt Lake County" (1994). All U.S. Government Documents (Utah Regional Depository). Paper 201. https://digitalcommons.usu.edu/govdocs/201 This Report is brought to you for free and open access by the U.S. Government Documents (Utah Regional Depository) at DigitalCommons@USU. It has been accepted for inclusion in All U.S. Government Documents (Utah Regional Depository) by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. FLOOD INSURANC STUDY IIOTIC! 10 VLOOD IBSUlABCB STUDY USBRS Co~iti •• partlclpatinl in the If.tiona1 Plood In.urane. Proar .. have e.t.blbbed repo.itorie. of flood hazard data for floodplain JUnaaeMDt and flood in.urane. purpo.... !hh Plood In.urane. Study _y not contain aU data available within the repolitory. It i ••elvil.bt. to contact the co.tuDity repolitory for &oy additional data. Part or .U of thi. PLood In.uranel Study ..,. be reviled and republi.hed at aoy ti.. ,In addition, part of tbi. Flood la.urane. Study ..y be reviled by tbe Letter of Map aevilioD proc••• , ¥bieb doe. not involve republication or rediltribution of tbe PLood In.urane. Study. It ia, tberefore, tbe re.ponlibility of tbe uaer to conault with cO.r\UDity officiala aad to cbeck tbe c.~ity repoaitory to obtain the moat current 'lood Inauranc. Study caponenu. Tbi. publication incorporate a reviaiona to tbe ori,inal 'lood In.tlraDce CITY OF Study. Tb.ae reviaiona are pre.ented in Section 9.0. SOUTH JORDAN, Thic preUainary reviaed 'lood In.uraace Study containa only profilea added or revhed aa part of tbe renudy. All profilea will be included UTAH in the final publiabed report. ,SALT LAKE COUNTY REVISED: SEPTEMBER 30.1994 Federal Emergency Management Agency COMMUNITY NUMBER · 490107 Ii",·/- r. ' ~ //1. / TABLE or CO!!'U!!TI TABLE 9. cotrmITS (Cont'd) Pale 1.0 ImoDVCIIOM Page 1.1 Purpo •• of Stud,. t.2 Authority and AckDovled... nu 1 . 3 Coordination •••••••• Pilure - Vicinity Map 3 Pigure - 'loadw., Scheaatic 14 2.0 AlIA SDIDIED 2.1 Scope of Btudy 2 2.2 COCDUDity De.cription 4 2.3 Principal 'load Probl._ Table 1 - SWIID4ry of Discharg•• 9 6 2.4 Plood Protection "ea,urea T.ble 2 - Ploodway Oeta 12 6 Table 3 - Jordan liver Proposed De,iln Di.charlel 18 3.0 QCIRRIMC I!Bl!!OPS 3.1 Hydrololic Analy ••• 7 3.2 Hydraulic Analy ••• Ezhibit 1 - Plood Profile. 8 Dry Creek Panels OIP-OJP Willow Creek Panels 04P-05P 4.0 PLQop P!.\I' IWMCIIIIRT APPLICATIO!S 10 Jordan River Panels 06P-07P 4.1 Flood IoUDclari •• 10 4.2 Pl"oct_,.. 11 PUBLISHED IBPAIATILY' s. C IlSl/I6IICl AlPLICAIIO! 14 Flood Insurance late Map Indes Flood Insurance late Map 5.1 .each Det.rwin.tion. 14 S.2 Flood a.&ard 'actor. (PHP,) is 5.3 .10od In.uunce Zone. 1S 5.4 Plood Io.urance ht. Map De.cription 16 6.0 rnA ID1DUS ••••••••••• • •••••••••••• 16 7.0 LQCAUO! DATA or . 17 8 . 0 8I1LIOCIAPIX A!!!l urlll!!C!I .•.••...••. • .• • .. 17 9. 0 1E'fI1I0! DIIClInIOIS 26 9.1 'int levhion 26 i i . I An inter-.diat. ~uni ty coordination ...ting was held on February 18, 1982, to allow ~nity repre.entaUve. to review the draft .tudy. Repre.entative. of the Pederal Bllergency Manage.. nt Agency, 1.0 IR'fIOJOC'rI(II the .tudy contractor, the U.S. ArllY Corps of Engineer., Salt Lake County, and the CiU•• of Sandy City, Riv.rton, Bluffdale, Draper • ....t Jordan, and South Jordan attended the Meting. Representatives 1 . 1 Purpo.. of Study trOW! sever al of the ~niUe. west of the Jordan River expressed concern that only approxiJlate atudies had been perforJlied on the '!bt. Flood Inlurance Study inv•• tigat e. the exiatence and aeverity .phe_ral atre_ that drain the Oquirrh Mountain.. It was explained of flCXJd haaard. in th. City of South Jordan, Salt r..k. County, that this .a. done because of the li_ited developaent on that side tJtab, and ala in tba IldainiaUation of the National Flood Insurance of the valley. Act of 196. and the Flood Di... ter Protection Act of 1913. '1'hh Itudy wl11 be UHd to oon.. rt South Jor dan to the regular prograa A final ~unity coordination Meting for Salt Lake County and of flood inaurance by the Pederal _'ganey Managuent Agency. the CiUe. of Riverton and South Jordan .as held on Deceaber It, LocaIl and regional planner. wl1l u .. thi. study in their efforte 1983. In attendance were repre.entativ.s of the Pederal Ellergency to pr~ eound flood plain __g_nt . Manag_nt Agency, the study contractor, the county, al'd the incorporated ~nit1es. 'J'Wo ..jar concerns raised at the Meting In eo.e atate. OE ~nltl •• , flood plain .ana~nt crlteria vere that the studies did not reflect flows frc. the 1983 flood, or regulaU0n8 _y I.lat that are ~1'. r ••trictive or ecaprehenllve and the conversion of the detailed study r.aches of the Jordan than tboM em which tile.. federally lupported .tueU•• are baaed. Riv.r between 2100 South Street and the North Jordan Canal Diversion '!be.. criteria ute preee4ence ewer the .lnt.. Pederal criterla Daa to approx1aate study. It .a. agr.ed that these probl•• would for purpoal of legulatlng ctt".los-nt 1n the flood plAlln, •• be addreuec1 during the appeal. period along with other aincr Nt forth in the c::ode of ,..,81 Ragulationtl at U CPR, 60.3. concerns raiNd by the individual co.aunities and the rounty. All In IIucb ca... , howe.. " it -.11 be underltc:lo4 that the State requesta were considered and, where appropriate, were acted upon (01' other juriadlctional agency) ahall be able to explaln the.. in the preparation of this study. requlr~ta and criteria. 2. 0 _ STIlDIBD 'l'he 8OU1'ce of authority for thi. Plood Inaurance Study i. the 2.1 Scope of Study Rational Flood Inaurance Act of 1968, a. _nded. 'l'tlia Plood Insurance Study cov.rs the incorporated areas of the 'lb. bydrologic and hydraulic analYH. for thia .tudy ver. perfor-.d City of SOuth Jordan, Salt Lake County, Utah . The area of study by RDUina, Brown and Gunnell, Inc., for th. Pederal _rg.nc:y ie ehown on the Vicinity Map (Figure I). lIaM~t Agency, under Contract Ro. &-"593. 'lbi. work, which wa. COIIIPlete4 in lII.y 1982, C09.red aU .ignificant flooding aources 'l'tle Jordan Riv.r and Dry and ..illow Creeks were studied in detan affecting South Jordan. for their entire length within the ~unity. 1.3 CoordinaUon '1'he cJetalled study reach of the Jordan Riv.r within South Jordan wa. converted to approxillllte study. 'l'tlia change r.sulted froa 8tre_ de.ignated for detailed and approxiaat. study were identified unc.rtainti.a in frequency analysis of the hydrologic data and at a ..Ung in Sept__ r 1977 attended by repre.entative. of frOli uncertaintiea in hydraulic .adeling caused by COIIpleted and the Itucty oontractor, the Pederal ...rgency llana~nt Agency, ongoing .o4it1cationa to the river channel initiated atter the kIt r..te County, and the City of South Jordan. ...ulte of the oc.pletion date ot thi ••tudy. In addition, downstre.. of the hydrologic and hydrauUc analyae. wre coordinated with repr ••enta­ WOrth Jordan Canal Diveraion 0.., proble. were encountered with U ... of the S.lt r..te County Public WOrk. Depart:.ent, Plood Control elevation data on the orthophoto topographic ..pe used for the and "tel' Quality Di.i.ion, the 0.8. ArIlY C»rpe of lIngi,,"r., detailed flood boundary delineationa, th.re were alllo di.crepanci.s anLt the 1ncorpcxated ~nit1e. of kIt Lake County. between the re.ult. of the step-backwater analyaie and the detailed flood boundary delineation.. Down.tre.. of the diveraion du, approxillate flood boundar ies vere taken fro. the Flood Basard Boundary Map (.. ferenee 1) . Up.tre.. of the diversion duI, approxi­ ..te flood boundaries were adopted fro. the atudy contractor'. detailed 100-year flood boundary delineations. , .- .. ' , -- .- I ,.' oJ' .. -- .. ...' ,-, - - -- - fl"111 thOle area•• tudied by detailed methods were chosen with considera­ tion ,iven to all propoaed construction and forec.,ted development flow .lIOothly. This point coincide. with a gradual deterioration tbrou&h 1987. of river quality a. it proce.d. downstream. Mid .. and Bingham. Creek. were studied by approximate methods . The County ...terplan use. the canals to carry .torm runoff to the Preliminat'y hydrologic and hydraulic analyses for these !Creams natural cb.nnels. The eace .. from the canal would be discharged to revealed tbat tbe approzimate 100-year flood boundaries shown on the natural channel. Hany improvements to the canals and the tbe Plood aazard Boundary Hap (aeference 1) were accunte; cbannele are required before this system can fully function. tberefore , the Flood Hazard Boundary Hap was cho.en .s the source of .pprozimate flood boundari .. for these stream•• Dry and Willow Creek. are intermittent stream. that drain the .outhea.tern part of the valley. These stream. have fairly steep Approai ..te .naly.e. were u.ed to .tudy tho.e are., having a low gradient. a. they era .. the terraces, but become quite flat as they develo~nt potential or minimal flood hazards.