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HomeMy WebLinkAboutDrainage Reports - 07/12/1995 (2)1 1 1 1 J ••4 d •.• Aq,. FIROPERTY OF POW COLDS 3yrnsrWA Final.Storm.brainage Report Final ad RopOi for 17 Evergreen Park Lots 17, • 18 and 19 U .. Zu�� �/`"�W JIq1�7idie, , \ 4 1�,��, May 1995 aLb-ff-L o�; �►�III�2 IWO.4QA N-_:.ytvQ;j;'��lI��I.P�`����I� �I�i ., v:9!11a IIt I, MWn 1Wrril4 Stewart & Associates Consulting Engineers and Surveyors 103 South Meldrum Street Fort Collins, Colorado 80521 (303) 482-9331 ?ter. I '44"U"C4410I 1 ' STEWART9,OLSSOCIATES Consulting Engineers and Surveyors ' May 26, 1995 1 1 t 1 1 1 Mr. Basil Hamdan Stormwater Utility City of Fort Collins P.O. Box 580 Fort Collins, CO 80522 Dear Basil: Re: Evergreen.Park Lot Improvements for Lots 17, 18 and 19 Attached for your review and approval is the "Final Storm Drainage Report" for Evergreen Park, Lots 17, 18 and 19. The project is.a light industrial "use -by -right" project for the Sinnett Builders. This project will include onsite detention for the development area for Phase 1, and a conceptualized detention sizing for Phase 2. Detention release from the furthest downstream pond will go into the existing storm drainage collection system in Conifer Street. A release rate of 0.44 c.f.s. has been established for Phase 1, and 0.42 c.f.s. for Phase 2, which will be allowed into the existing facilities. Both of these rates are equivalent to the 2-year historic rates. All hydrologic and hydraulic designs in this report meet the City of Fort Collins, Storm Drainage Design Criteria and Construction Standards (1984). Should questions or concerns arise regarding this project during your review, please do not hesitate in contacting our office. Sincerely, Richard A. Rutherford, P.E. & L.S. President rsc enclosures James H. Stewart and Associates, Inc. 103 S. Meldrum Street P.O. Box 429 Ft. Collins, CO 80522 303/482-9331 Fax 303/482-9382 * 5028 i ' A FINAL DRAINAGE REPORT EVERGREEN PARK, BLOCK 3, ' LOTS # 179 189 19 ' GENERAL SITE The current proposal is for Block 3, lots 17, 18 and 19 of ' Evergreen Park, which will include light industrial manufacturing facilities on ± 2.47 ac. This project is a "use -by -right" in the ' I-L, Limited Industrial Zoning. Block 3, Evergreen Park, is located on the Northwest corner of Red Cedar Circle (Red Cedar) and Conifer Street (Conifer), with lot 19 beginning ± 150 feet North of ' Conifer. The available uses do require an engineering package with a site plan, utility plan, and storm drainage report including a ' grading and erosion control plan. Curb and gutter along both Conifer and Red Cedar have been designed to accommodate this land use. ' The site falls in the Dry Creek Drainage basin at the confluence of the floodplain with the Poudre River. The Poudre ' River and Dry Creek basins are the basis of design for establishing finished floor elevation that meet the flood proofing criteria of the City of Fort Collins Storm Drainage Design Criteria and ' Construction Standards (SDDCCS). Pertinent exhibits of the 1984 Flood Insurance Rate Maps are included in the appendices of this ' report. onsite detention will be provided with the release going ' into the existing piping system in Conifer. It has been confirmed that this point of release is acceptable to the City Storm Drainage ' Utility. Design criteria in this report meet the SDDCCS. 1 I Evergreen Park, Lot 17, 18, 19 Final Storm Drainage Report Page 2 Two Phases are being included in this proposal; generally. lots 18 and 19 will be Phase 1 (1.56 ac) and lot 17 Phase 2 (1.18 ac). The discrepancy in total platted acreage is because the alley West of the project.. sitehas been included in Phase 1 planning. The storm drainage design shown will conceptualize the necessary design elements to allow Phase 2 to ao forth with minimal fnT-t}iar-rcxrjcT.. Should the intended land use chinge, the storm drainage design should be revisited. HYDROLOGY EXISTING CONDITIONS Ground covers on the site consists of rangeland grasses and weeds that during storm events generatesheet flows into the existing curb and gutter along Red Cedar and Conifer. With ground sloping at or below 1 percent to the Southeast, historic times of concentration (TOC) are large with Phase 1,_32.2 minutes and Phase 2 being 22.0 minutes. These long TOC's have resulted in small allowable release rates from the detention facilities shown. The Rational Method used for the hydrologic evaluation -showed that the two year historic release rates from Phase 1 would be 0.44 cfs, and from Phase 2, 0.42 cfs..This 0.86 cfs release will be the maximum allowed flow exiting the combined lots 17, 18 and 19. Streets will not be modified as part of these construction activities, so no references will be made toward this unmodified issue. 1 11 U Evergreen Park, Lot 17, 18, 19 Final Storm Drainage Report Page 3 DEVELOPED HYDROLOGY Under the SDDCCS criteria, the proposed industrial use will require assessment of the 10-year and 100-year storm occurrences. Any increase in direct runoff above the 2-year historic resulting from intensified land use must be -detained onsite. Detention pond release will be set with its maximum at that calculated 2-year historic rate. With a composite runoff coefficient calculated for each phase of the project, and TOCs' based on the site design, flows were calculated by the rational method. Phase 1 in the 10-year recurrence would develop a flow of 4.9 cfs, and 12.0 cfs in the 100-year. Phase 2 in the same order generates 3.5 cfs and 7.5 cfs as direct runoff. EVERGREEN PARK, BLOCK 3, LOTS 171189 19 DRAINAGE SUMMARY TABLE BASIN AREA (AC) Historic QJo CIO Qioo C100 Phase 1 1.33 0.44 cfs 4.9 cfs 0.80 12.0 cfs 1.00 Phase 2 1.18 0.42 3.50 0.73 7.50 0.91 ' NOTE: Historic conditions use a "C" of 0.20.in both cases. Detention will be provided for both phases `of the project ' separately, with facilities to release into a storm drain to be constructed along the East property line. Half street flows along Red Cedar have been calculated and ' shown in the appendices. No change in these flows will be proposed as part of the two phases presented here. ' Evergreen Park, Lot 17, 18, 19 Final Storm Drainage Report ' Page 4 Also flows from the existing alley have been determined and again ' are included in the appendices. These flows will increase because of the asphalt surface that will be applied to the existing gravel. ' The minor increase in runoff'0.6 cfs in the 2-year and 1.2 cfs in the 100-year will be directed into the north flowline of Conifer. At a point approximately 325-feet away it will be collected by the existing inlet at the Red Cedar and Conifer intersection (see drawings). HYDRAULICS ' Two detention ponds are being required of this project development, one in Phase 1 and the second in Phase 2. These ponds ' will have inlet control by means of an orifice plate and be piped to the existing storm drainage piping located in Conifer. As mentioned earlier it has been suggested that since the 2-yr ' historic release rate is not exceeded, that detention release into this existing system is acceptable to the Storm Drainage Utility. Detention release is to be piped toward the inlet at the Red Cedar and Conifer intersection where the connection to that existing system will be made. This will provide for a minimum impact to that curb inlet while still allowing runoff to be collected in that existing piping. Because the flows are small i.e., less :'than 1.0 cfs from both Phase 1 and 2 combined, analysis of that existing system has not been included as part of this design effort. Evergreen Park, Lot 17, 18, 19 Final Storm Drainage Report Page 5 A 15-inch RCP pipe laid at a slope of 0.20 percent will provide adequate capacity for 'these low flow volumes. This pipe will be laid within the easement next to Red Cedar (see the drawing package ' accompanying this report for details of this new pipe ' installation). Design for orifice plates will be addressed as part of the Detention section of this report. DETENTION ' Detention will be a part of both phases of the current project design. The two. proposed facilities will be on the East property ' boundary next to Red Cedar. This arrangement will take advantage of the naturally occurring topography that slopes to the Southeast. tPhase 1 will be constructed as part of this proposal and the Phase ' 2 will be conceptually sized. The Phase 1 pond, using the allowable release of 0.44-cfs ' shown, requires a volume of 0.26-ac.ft. This was the result of an analysis by the FAA Method using the SDDCCM 100-yr design storm and ' a runoff coefficient "C" of 1.00. Grading in the area identified ' for detention using this required volume showed a high water line (HWL) of 4969.63-ft. These. design elements translate into a circular orifice plate with an area of ± 4.5-in or a radius of ± 1.35-in. Placement of this orifice will be at the flow line of the 15-in RCP previously mentioned. ' Because of the uncertainty of the time table and specific land use, only a conceptual detention pond has been calculated for the Phase 2 pond on lot 17. I 1 L L] 1 Evergreen Park, Lot 17, 18, 19 Final Storm Drainage Report Page 6 Using similar design criteria to that included in Phase 1, except the runoff "C" of 0.91 for Phase 2, a pond requirement of 0.21, ac.ft. was determined. This is based on the historic release rate of 0.42 cfs for this phase. Assumptions associated with the runoff coefficient are based on the information included in the drawing package accompanying this report. CONCLUSIONS This use -by -right project is consistent with the type of land use anticipated for this basin. Regional development within this basin has reached a point where the lots experiencing development will not present a concern. Though the lots are in the floodplain for the Dry Creek and Poudre River basin confluence, finished floor elevations have been set to meet the requirements of the FIRM map. A variance for the 1.5 foot freeboard requirement by the City of Fort Collins was granted by the Storm Drainage Board. Additional technical data was provided which established the base flood elevation to be 4972.75 feet. The finished floor elevation will be 4974.00 feet. Evergreen Park, Lot 17, 18, 19 Final Storm Drainage Report Page 7 It, is not foreseen that complications associated with this minor development will affect the adjacent land use or current land owners, now or in the future. During your review for approval, should questions arise regarding any aspect of this report, please feel free to contact Alex Evonitz or myself so we may help in your understanding. Respectfully, 9 Richard A. Rutherford, P.E. & L.S. #5028 ��G18TEgF` •. G 5028 f & L• �:IQO. 1 1 1 7 L1 1 EROSION CONTROL REPORT The project site in the Northeast quadrant of Fort Collins falls in an area of moderate rainfall and wind erodibility. Site size plays an important role in deciding what physical and cover measures will be required during construction. Phases 1 and 2 are small in area and modest in ground slope. These factors lend themselves to a simple erosion system to be installed and maintained during construction activity. Phase 1 is on the Southern portion of the site and, including the alley, covers 1.56 acres. The alley, which is 0.27 acres, will be paved early in the construction, and the foundation area of 0.34 acres can be subtracted from the total. Remaining is 0.95 acres that will be susceptable to disturbance by construction activity. The attachments to this report show that the highest exposure,to wind and rainfall erosion will be during the grading of the parking areas and detention facilities. Before this soil disturbance, a gravel filter will be placed at the curb inlet at the Northwest corner of Conifer and Red Cedar. Additionally, silt fencing will be placed around the East and South boundaries. When the detention facility for Phase 1 is constructed on the East side of the building, a straw bale dike will be placed at the outlet. This combination of structural elements along with temporary vegetation in the detention pond will bring the Phase 1 erosion control performance above the 72.5 percent required for the site. 1 Evergreen Park, Lot 17, 18, 19 Final Erosion Control Report ' Page 2 Phase Two will cover 1.18 acres, with the building foundation ' enclosing 0.34 acres, resulting in 0.84 acres being susceptible to disturbance. Silt fencing will again be installed to surround the site on the East and South boundaries. A gravel filter will be ' placed at the curb inlet at the Northwest corner of Conifer and Red Cedar, if the filter placed there from Phase 1 has been removed. ' During the site grading of the parking and detention facilities, the highest exposure to rainfall erosion will occur. The structures ' identified, along with a temporary vegetation cover in the ' detention area, will provide an erosion control performance comparable to the existing one. ' Two temporary vegetation mixes are being provided to account for the early and late construction season since exact timing is ' uncertain. This variable in cover seed mix will need to fit the 1 season's specific construction activities. The design presented will account for erosion of both Phase 1 and 2 of Evergreen Park, ' Block 3, Lots 17, 18 and 19. Should a significant land use change in Phase 2 of the design area occur, the erosion and storm drainage ' will need to be revisited. Should questions arise during your review of this report, please do not hesitate in contacting our office so we may assist in ' your understanding. EROSION CONTROL COMPUTATION FOR EVERGREEN PARK LOT 17, 183, 19 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 STEWART&,SSOCIATES 10 82- DR31 FM, FOR AX OT COLLINS, CO 80521 PH.Consulting Engineers and Surveyors By: Date: 10-2(a-'J4} Client: Sheet No. of Project: ��ye�t�2 � �tR� t _ �x_vc �t ion n , r P, 19 Subject: -T—s7bs, o.. C �-Tlc;e _ 1 I' -__I..- .I --I II�I�!IIi! Ill, A its ?ax. CcrA 171 19 19 CONSTRUCTION SEQUENCE PROJECT; __t�kacm l s i►+,oss Z STANDARD FORM C �gUENCE. FOR 19 95 ONLY COMPLETED BY: ALk- DATE: 3- 0-,T ficdte by use of a bar line or symbols when erosion control measures will be installed. or modifications to an approved schedule may require submitting a new schedule for approval by the.City Engineer. ' YEAR • MONTH I ------=---------------- S IF -----�---- ----. ---i--- RLOT GRADING 01 14IND EROSION CONTROL I ' .'Soil Roughing i Perimeter Barrier Additional Barriers I1; 'Vegetative Methods Soil Sealant Other ; RINFALL EROSION CONTROL 'STRUCTURAL: Sediment Trap/Basin Inlet Filters Straw Barriers Silt Fence Barriers Sand Bags Bare Soil Preparation 'Contour Furrows Terracing Asphalt/Concrete Paving Other VEGETATIVE: ' Permanent Seed Planting Mulching/Sealant Temporary Seed Planting -Sod Installation Nettings/Mats/Blankets Other ----------------- TICTURES: INSTALLED BY MAINTAINED BY EGETATION/MULCHING CONTRACTOR Sraw�t At SUBMITTED 3-J5 APPROVED BY CITY OF FORT COLLINS Oil DISF-C:1989 i I is i ' _LL LL--L i I Rainfall Performance Standard Evaluation EVEKG�� Q "PAR\C , . BLOCVL 3 Project: LoY3 ' 171 10 , i5 Standard Form A By. . Stewart & Associates Completed: kv� 103 S. Meldrum Fort Collins, Colorado 80521 Date: IO /ZG/ Developed Subbasin Erodibility Zone Asb acres Lsb feet Ssb % Lb feet Sb % PS % fr g WINS Z.��� 4 b,_i 72,-S 'o0 7Z.4 �2.!3 4CO NOTE'. P 51N41E 11t F Fto.JN � e- ZOT}Ak -1 tt-a 5'c 1 2, r r'r � � Z HDI/SF—A:1989 1 1 1 1 i 1 1 1 1 1 1 1 1 1 1 i 1 1 STEWART&O SSOCIATES 10 S. 933 RUM,FAX FORT gOLLINS, CO 80521 Consulting Engineers and Surveyors By: + Cv� Date: Client: Q0,0 ti•r - T? i E Sheet No. of f Project: �vo�zq,2n� �t �i� t�io� 3 Loy S 17 t F. l i Subject: J Cou)TRoc., Co,,Y• r — Ct.o,� �R0 JECT too ,auAZ Y �JTIH 5IST ( _Z—_-' -- .r ht i I A7 .1vlaT o ►.; i t �.W. t 1 --—!_,--T__—I - jj �-�!`AiL, I O� I _._�� ��R�%. S . �l..uv N. LriC� __I I ! I - -- —_f �?CC�vAiZU•..I wi�I� I g` IIJrD�2�wK�u� ':�� � r-o�R.S R �.�,c�. �a - (_._ e;t �b �� n ac Kc LEI 0_p%0A 14 Ij , i I 1 1 II -I--- --� �-- ---�� IDS t - r� �`�✓oQS7':��_Ql�t�oS�.. I , �_ � �.; o� i Gew',�ZvcZo. ! ' ! I � 1 1 -t— i -- I Effectiveness Calculation T 17 1$ i5 1� Standard Form B Project: Sj�s�ci, By: Stewartes Completed: A.Q. 103 S. Fort Crado 80521 Date: 10 /� / S d Erosion Contro FactorMethodValue Value O. 8 E0,1itll. S I E Wtr� ?p`-S TRP - Z1. SreA, > eAOL. +. a� � fi ARYL 5iu— c>ca, l.o 0.= t . a _ . 6?0 ✓oe eol HDI/SF—B:1989 Effectiveness Calculation �z CUEL5Re�1-) �AiL'L Proiect: gLn. (� �� I g Standard Form B By: Stewart &.Associates Completed: Al1•Q 103 S. Meldrum Fort Collins, Colorado 80521 Datc: 0 / 26/ Erosion Control C— Factor Y —Factor Comments. Method Value Value Q f/A'R1L SOIL Ss¢�w 13A I'� �%� QoutiN 1.27t7�JtK1iL 4eaveL- � c1� t , o .ao S, LT O t7 %ZAuQL (,o ado Cb a2> l SD DCCS v e P-( ■ HDI/SF—B:1989 •1 STEWART&ASSOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 1 Consulting Engineers and Surveyors By: Date: 10-Z(,-54- Client: UAUiH - !F YyE Sheet No. Of 1 Project: L_yE n �� 2aa . e m_- Lors 1� , 16, Subject: CO.J` X • — 1--'+ i-+�R�—�Z-LI__IIl 'ItA C I�L(.F`I to )Y__ P I<��iwal r1 tEF i(_� 'tl-�Q� il 1. i'•_) f - - -- - - -�..? = Cxcr.l)P���w �f_- iF��rt_I F�� _'� ;; . o� s: rz•�Tua� A 2-� Qv { , j Lra �1 _ C�Z AsSeSI i 'frte13T. IPc i�c� �! +sxwi� I CtZAar��(t ------� --i---- ----��MCC -1 PZKtr?I_g �c .CIIwip«tC�j ...ilk "�u•2- c�C CtZIN-W•�� tti C'a� �:�CvteU 'c i �� . �'i wtC� lY`c- r`�r oru3� - --- -- --i _1 __1 -t--1 --I 1►,.�_ illy Pc��fl �1=1-5}!c I �t�.e..,�i..i I 1 I I � i ! ,_ 1 ! i � _I I•_�Y'RC:.;.._ ��L-_ I(...)�D BL��.! _._`_. � i i I i I i 1 � csr or___T ERoSo . I �au12�.s I �Ca �;T, ' i Iti I , 1 Effectiveness Calculation iEvC2y2g� t` A Project: tcetz '' i q, c Standard Form B By: Stewart & Associates Completed: Ptc"4— 103 S. Meldruw Fort Collins, Colorado 80521 Date: 10-14 Erosion Control Method C— Factor Value Y — Factor Value Comments: 13ftY_a.. 1.0 - TzT1,OLAQ- CRA 'O O, gd JILT i'[�tC I, O O 1Za >tM.a Crz 0 Co I.0 (Do% (Fit) -15,> SDi S .� Basin (%) - (acres) L' lC x P�� \` tom" Mcru�2. \ 96 6ILI � 141a� t ZZ�t 1 HDI/SF—B:1989 L PAGE 23 1 1 o I D�rnoco • i 0 1 v C to In to t a7 1 qqqq q O I cn CD) m D) C G O 0 CD 0 1 G t V C' C' 4 U) U) U) to In C' 1 =wW=WWCCwWW I I O I C. 4aCv CC4C CcV 1)n U) M I g q q q q q q q q O C qqqq q O O 1 Q' c1' V c' C' C C' C ct C' C' V C' ct C• cf C• ' N F co co w qqq'q q'ggqq= qqqqqqco I O I C M -:1, Ln l0 lO tO tD 1, 1, t-, t-, I, 1, f-, 1-7, 1-, 1-, 1-, 1-, q q q q q q 1 O I C' 4 C' 4 C' 4 C' C' 4 C'C• 4C' 4V 4C' C' 44C' 44 444 g q q CO W g q q q q q q q q 00 g q q q q w q q q q W 1 O I qNM C'U7 Ln Ln LD LD LD LD LD LO n n f\ n n r\ r" r\ f\ r\ q qq I . . . . . . . . . . . . . . . . . . . . . . . . . . . O'. I Mct cY�-zrC'ct•MTC'C'C-C•C'C'cC'C•d•d•C•mil C•C•C'C•C- 1 q q q q- 00 00 00 g q q q q q q CO.CO q q q q 0000000000 I O I to O N M C- d• LO Uf to Ln L0 LO LO LD LD LO LD LD LD L0 r., ^ f\ r\ r\ n . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . q I M C'.-:T C' C' C' C' C' C' C' cf C' C' C' :I- C' C' Cr C• C• C- C' C' mj' C C' I g q q q 0': g 00 q 0000= q q q q q q q q q q q q q q 00 1 O 1 C'a%.--tN MMC'MI, d•C•tr Ln Ln LO Ln V) Ln Ul U7 LD LD LD LO LD l0 r, I n I M M cY -::I- C' C' Q' C' MT ct d- C� C' C' C' C• C' C' Cl- C• C' d- d• C• C' C' 1 g q q q q q q q q 00 00 00 q q q q q q q q q q q q q q I O I OLO co CD +NNMMMM C•C•cf V C•ct zr U: Ul Lo Lo LO LD • I 10 1 M M M :Zr V' C• Q' C' C C' C C' C' C• C' C' C' C' C C' V C' I g q 00 00 00 00 g q q q q q q q q q q q q 00 0000 q q q q 1 C iLn N Ln r-, co C71 CD -�.--CNN N N N N M M co co ct C'C- C' C' . . . . . . . . . . . . . . . . . . . . . . . . . DLO I NMMM MM �C G' C•C C'd-C' C' ct -a- C' C'C' C"C'C'4 V C• W I a.*; co co co 00 00 00 cc 00 co CC ccq co co co a, co co co co co co OD 00 a. Ul 1 .r co M C• U) Ln LD 10 r\ n r-_ g q q q q 00 m CT m C C O 00 O 1 JC• I NNMMMMMMMMMMMMMMMMMMMC'C'C'cY C' to I CC CO g CO 00 00 CO 00 CC g CO q CO 00 CO CO CC CO CO CO 00 CO 0000 q 00 1 O 1 LD Ln q cD iNMd'C' Ln Lo Lo LO LO LD LO LO t-, 1-% t-, t-.. q q q cn cn 1 C' 1. C\i NC)M(nmm mm cn cn M m m M m m Mf") M M rM MMM I g q q q q q q 00 00 g q q q q q q q q q q q q q q 0000 1 Ln 1 rl`4Ln1-1gOC.--tNN M M MC'C'.C' C' C' Ln U) Ln%D%D t.0 nn • I M 1 r-INNN N M C"7 M M M M M M M M C") M M cl "C4wMMMMM I q q q q q q q q q q q q q q q q q q q q q q q q q q 1 O 1 MNID mmC.--INNMMM Cl C• -.t C' ct cY to UI Ln Ln LO LD LO LO I M. I G 1- N N N N N N N N N N N N N N N N N N N N I g q q q q 00 qc 00 00 g q q q q q q q q q q q q q 00 q 00 I Lo I Ln Ln cn"m-c' Ln LD 1--1--I--q qq Ol mm Q) m CT OOOOOO 1 . . . . . . . . . . . . . . . . . . . N I (n C CD.--t .-+ .-t r+ rr .--I .-+ .--I r/ .--i .--i .-. r+ •--I ti r+ N N N N N N I r-- CO CO W CO g q CO CO 00 q CO CO CO CO CO CO CO CO CO CO CO 00 00 0000 I O I C• Ln O M Ln i0 q 0b cn CDC) Ir+.-tN NNNMMMMMM 1 N 1 q 04 O O O O O O O .-i .--I .-r .-I r..--1 .--i .--t I r-I r-- g q q q q q q 00 g q q q 00 00 q 00 00 00 00 00 00 q q q I U) I w"cc Ica- Ln r.- l-- gm M4=OMMMMM qq O) 0(n IT O) Q) CT CI) O O O O O O O O O O C 0OOO I n n r, r-, r-- r-, r-,r�, r-, l%, r,, 00 00 00 00 CO CO CO g CO CO CO CO CO CO CO 1 O 1 10.f•'. . C. t\ m cD ..--. . . . C. C' to Ln Ln to LD lD tD LO n r-,t0 l0 to • 1 LO 1l- 1\ r-I (\ - q q q q q q q q q q q q q q qco* co, CO q t\t\t\nr\r\r\f-I r-I r\ I,, n n n r.- r� nr-If�t\f�t\t� Ln ) D)OC•l0 q gr-I r"f.,l0 t0 l0 In C•C'MMNNO)l0 C'e--1 cn to O O. NN NN NN NNNN NNNNNNNN.--t .--i r-1OO I n n n t\ r n n n t\ n r n n n n r l- n r, f\ I,, f l, I,- r-- n n n 1 0000'00 C 0 O O O O O O O O O O O O O O O O OO 1 0 C> F- I O O O O O O O O O O O O O O O O O O O O O O C O C O I JZLL I NN M C Ln LO r� q CT Imo .-+NM V Ln LD rl- q O) O Ln O Ln O U7O I U- W �. 1 A r+ .--r .-� r• •r N .--r .--t N N co M V C' to 1 J 1 lP 1 1 1 1 1 1 1 I 1 1 1 1 I I TABLE 5.1 .9 M IZ ' PAGE 24 ' Table 5.2 C-Factors and P-Factors for Evaluating EFF Values. Treatment C-Factor P-Factor ' BARE SOIL Packed and smooth . . . . . . . . . . . . 1.00 1.00 Freshly disked. 1.00 0.90 Rough irregular surface . . . . . . . . . 1.00 0.90 ' SEDIMENT BASIN/TRAP. . . . . . . . ... . . . 1.00 0.50(1) STRAW BALE BARRIER, GRAVEL FILTER, SAND BAG. 1.00 0.80, ' SILT FENCE BARRIER . . . . . . . . . . . . . . 1.00 0.50 ASPHALT/CONCRETE PAVEMENT. . . . . . . 0`O1 1.0.0 ' ESTABLISHED DRY LAND (NATIVE) GRASS. . . See Figure 1.00 ' SOD GRASS. . . . .. . . . . . . . . . . 0.01 1.00 TEMPORARY VEGETATION/COVER CROPS . . . . . . 0.45(2) 1.00 ' HYDRAULIC MULCH @ 2 TONS/ACRE. . . . . . . . . 0.10(3) 1.00 SOIL SEALANT . . . . . . . . . ..... . 0.01-0.60(4) 1.00 ' EROSION CONTROL MATS/BLANKETS. . . . . . . . . 0.10 1.00 Ad CiJZjP,V-02- L-- ' HAY OR STRAW DRY MULCH 103- O After planting grass seed, apply mulch at a rate ot Z tons acre (minimum) and adequately ' anchor, tack or crimp material into the soil. Maximum Slope Length ' M (feet) 1 to 5 400 . . . . . . . . 0.06 1..00 6 to 10 200 . . . . . 0.06 1.00 ' 11 to 15 150 _ . 0.07 1.00 16 to 20 100 • •0.11 1.00 21 to 25 75 . . . . . . . . . 0.14 1.00 25 to 33 50 .. . . . . . . . . 0.17 1.00 ' > 33 35 0.20 1.00 NOTE: Use of other C-Factor or P-Factor values reported in.this ' table must be substantiated by documentation. (1) Must be constructed as the first step in overlot grading. ' (2) Assumes planting by dates identified in Table 7.4 thus dry or hydraulic mulches are not. required. (3) Hydraulic mulches shall be used only between March 15 and May 15 unless irrigated. t (4) Value used must be substantiated by documentation. . BASIN CONSTITUENTS FOR EVERGREEN PARK LOT 179 189 19 Y 3 ai o T a 0 C T m A Z O OJ Y (=j C— J Q W Uwe O Q L v c Owr Z > 3 D wN Z m Lw cn f Fn m 1..1..E � � 2Z) OU) U= Q Mw I..L rn O 2 W m O F U O Lt E O N� T ~ O c T ~ O J U m 2N O Y T C 0 ca C Y O C O � wo (mo Uo Y N in 0) (� d u < o C II > QCZ0 c c N O C U O C :E ~ Do) o O 3 d ==T- c II E -� IM U cyo M II F- ate-+ (D a) c o co C U C > o o O U0 LL co % O W E �U CD 0 0 0 c c N m II c cc L- Z-1 1 1 1 N V� 1 1 1 1 1 1 A E L U— L ca C m U) 00 C C0 T cm ay o T Ui z a _ 0 J � m V C Y L 2 v0 4 (a o ° O)m C Co � L p° CTJ Q pl L Q c0 > E W C. 0 l) 0 J ^M —o I 1 1 I I 1 1 [] 1 STEWART&kSSOCIATES 103 PH. S. 9 DRI A , FORT 8OLLINS, CO 80521 Consulting Engineers and Surveyors By: POAZ Date: 2--13-75 Client: 'F- - Sheet No. 1 of Project: tvea e}g�� 0, 18 . 19 Subject: Yy Siftae7r ,2. �a.� CES�tr2 Qpp- Qi STEWART&&SSOCIATES 103 S. MEL9331DRUM,FAX FORT gOLLINS, CO 80521 Consulting Engineers and Surveyors By: Date: Z- 13'SS Client: Jh)�oT — 54-el Sheet No. of I Project: �--��2aow �az� i S i 1 g Subject: Itt-L%1 00 \Nov i i ! IOC"�MM1- i ljw :17TZ~19t 1. - Cxi 5w,w 3 kf-e- M,sor--4 'Foe- ! I ! l lily I � , I! ! II i i I I , 1 r � �" •'A :, ,°� DRAINAGE CRITERIA MANUAL RUNOFF 5C 30 1- 2 0 z cc U a 10 z w a 5 Cn w cc 3 O co 2 w H a C 1 NO ■ I I �SEEN I■■■■m MEN �_ milli milli / •, ' 11 I' ��■I®■��■��■►i■WAWA MM ■M■E■■� .2 .3 .5 1 'S 2 ' 3 5 10 20 VELOCITY IN FEET PER SECOND FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR I USE WITH THE RATIONAL FORMULA. *MOST FREQUENTLY OCCURRING "UNDEVELQPED" LAND SURFACES IN THE DENVER REGION. REFERENCE: "Urban Hydrology For Small Watersheds" Technical Release No. 55, USDA, SCS Jan. 1975. 5 -1-84 URBAN DRAINAGE & FLOOD CONTROL DISTRICT HYDRAULIC ELEMENTS FOR EVERGREEN PARK LOTS 17, 18 and 19 ----------------------------------------------------------------------------- UDINLET: INLET HYDARULICS AND SIZING ' DEVELOPED BY DR. JAMES GUO, CIVIL ENG DEPT. U OF COLORADO AT DENVER SUPPORTED BY METRO DENVER CITIES/COUNTIES AND UD&FCD ISER:Stewart and Associates. -Ft Collins Colorado .............................. ON DATE 02-15-1995 AT TIME 12:01:28 '** PROJECT TITLE: West Red Cedar *** COMBINATION INLET: GRATE INLET AND CURB OPENING: ' *** GRATE INLET HYDRAULICS AND SIZING: INLET ID NUMBER: 1 INLET HYDRAULICS: IN A SUMP. ' GIVEN INLET DESIGN INFORMATION: INLET GRATE WIDTH (ft)= 1.50 ' INLET GRATE LENGTH (ft)= 2.00 INLET GRATE TYPE =Type 16 Grate Inlet NUMBER OF GRATES = 1.00 SUMP DEPTH ON GRATE (ft)= 0.00 ' GRATE OPENING AREA RATIO M = 0.60 IS THE INLET GRATE NEXT TO A CURB ?-- YES ' Note: Sump is the additional depth to flow depth. STREET GEOMETRIES: STREET LONGITUDINAL SLOPE (%) = 0.30 STREET CROSS SLOPE M = 2.00 STREET MANNING N = 0.016 GUTTER DEPRESSION (inch)= 2.00 t GUTTER WIDTH (ft)- = 2.00 l m t STREET FLOW HYDRAULICS: _. WATER SPREAD ON STREET (ft) _ GUTTER FLOW DEPTH (ft) = FLOW VELOCITY ON STREET (fps)= FLOW CROSS SECTION AREA (sq ft)= GRATE CLOGGING FACTOR M = CURB OPENNING CLOGGING FACTOR(%)= INLET INTERCEPTION'CAPACITY: FOR 1 GRATE INLETS: DESIGN DISCHARGE (cfs)= IDEAL GRATE INLET CAPACITY (cfs)= BY FAA HEC-12 METHOD: FLOW INTERCEPTED (cfs)= BY DENVER UDFCD METHOD: FLOW INTERCEPTED (cfs)= 17.41 CP?nC 7y Q FU(L 0.51 "�� Cu23uue. 2.03 3.20 50.00 20.00 6.50 5.54 2.77 2.77 *** CURB OPENING INLET HYDRAULICS AND SIZING: ' INLET ID NUMBER: 1 OA%S IULGT VAbrr-L IS fog USE ItJ DET 12rA'1pliWj MAx.I=''La .IVA &+%Fdt 5.1�. INLET HYDRAULICS: IN A SUMP. GIVEN INLET DESIGN INFORMATION: GIVEN CURB OPENING LENGTH (ft)= 2.00 HEIGHT OF CURB OPENING (in)= 6:00 ' INCLINED THROAT ANGLE (degree)= LATERAL WIDTH OF DEPRESSION (ft)= 45.00 2.00 SUMP DEPTH (ft)= 0.00 Note: The sump depth is additional depth to flow depth. iINLET INTERCEPTION CAPACITY: IDEAL INTERCEPTION CAPACITY (cfs)= 4.76 BY FAA HEC-12 METHOD: DESIGN FLOW (cfs)= 3.73 ' FLOW INTERCEPTED (cfs)= 3.73 CARRY-OVER FLOW (cfs)= 0.00 ' BY DENVER UDFCD METHOD: DESIGN FLOW (cfs)= FLOW INTERCEPTED (cfs)= 3.73 3.73 CARRY-OVER FLOW (cfs)= 0.00 ' *** SUMMARY FOR THE COMBINATION INLET: THE TOTAL DESIGN PEAK FLOW RATE (cfs)= e BY FAA HEC-12 METHOD: FLOW INTERCEPTED BY GRATE INLET (cfs)= 2.77 FLOW INTERCEPTED BY CURB OPENING(cfs)= 3.73 ' TOTAL FLOW INTERCEPTED CARRYOVER FLOW (cfs)= (cfs)= 6.50 0.00 .BY DENVER UDFCD METHOD: FLOW INTERCEPTED BY GRATE INLET (cfs)= 2.77 ' FLOW INTERCEPTED BY CURB OPENING (cfs.)= 3.73 TOTAL FLOW INTERCEPTED (cfs)= 6.50 CARRYOVER FLOW (cfs)= 0.00 1 - ' Ttt%T Toe E___1r1*W S (cv"Q10ano,,.. IUIJVCS WkLL la't.eaPY-© --;�vLL C09-b "Dc4-1 Coopl-nioos 10 STEWART9,06SOCIATES 103 S. MELDRUM, FORT COLLINS, CO 80521 PH. 482-9331 FAX 482-9382 Consulting Engineers and Surveyors By: Date: 2- IS -9S Client: v�,Hr-F,21;E �, n� Sheet No. of ' Project: _-IZ-vot4ilw,,. �„,L Lvrs Subject:0. Ire S.� . rcl�l a4 SC�+�n V�TIG. _ ——�--L.._1---�,�;:oi ,o-- f - I�.'� --i - - 1 1 -- -I ( I � I i I I ! • lO, _ , I i 4l61, I I I Mw�•!�oc.L lNeaa �I kYJS�INL�� 0 - P�Jwa„I Sra,x�a. Fort) vw9��u'a-1 __-____��I Imo_- 1 -{ i • I • � ! ; 3040 i cA- lU1.'� I' Q15 Rcr I ! ; I - - -- - - i ei G i 1 - - - -�� - ( I I (I I I �t i3o i v� of ! 12c 2 41Zuo rda,Z I ' CC a`,u ee G5•�9 77 \00 ► � ReP i h� 400 112" 2c. Zoo j, jisj I o,z90 I 13ot� i Z33 I 0,27o I ' I I_ _ � i --I I- I -i� ( I I � i I i I I I'�rY�Co i � ! • ! I_yI,K TeI I .I` ,i•, J KtAKl e.W 1w Fi� IJ10 Tr�F I e�QSTI FYt Ca-^I'i, �'RTlov�, IUIO-i$ - I I i-A T1tE l teST o�`� v (RDr"t i vi I R l ia aK. on,; 1 ' STORM SEWER SYSTEM DESIGN USING UDSEWER MODEL Developed by Dr. James Guo, Civil Eng. Dept, U. of Colorado at Denver Metro Denver Cities/Counties & UDFCD Pool Fund Study �SER:Stewart and Associates -Ft Collins Colorado .............................. ON DATA 02-16-1995 AT TIME 12:28:00 VERSION=01-30-1995 ** PROJECT TITLE :Evergreen Park *** SUMMARY OF HYDRAULICS AT MANHOLES ,------------------------------------------------------------------------------ MANHOLE CNTRBTING RAINFALL RAINFALL DESIGN GROUND WATER COMMENTS ' ID NUMBER AREA * C DURATION INTENSITY•PEAK FLOW ELEVATION. ELEVATION MINUTES INCH/HR CFS FEET FEET -------------------------------------------=----------------------------------- 10.00 0.00 0.00 0.00 13.86 68.50 65.22 OK ' 20.00 0.00 0.00 0.00 7.36 68.20 65.67 OK 30.00 0.00 0.00 0.00 0.86 68.70 66.41 OK ' 40.00 42.00 0.00 0.00 0.00 0.00 0.00 0.00 0.86 0.42 70.00 70.00 66.44 66.45 OK OK 41.00 0.00 0.00 0.00 0.44 69.60 66.45 OK 21.00 0.00 0.00 0.00 6.50 68.20 66.04 OK 50.00 0.00 0.00 0.00 6.50 68.20 65.02 OK 51.00 0.00 0.00 0.00 6.50 68.20 65.18 OK OK MEANS WATER ELEVATION IS LOWER THAN GROUND ELEVATION ** SUMMARY OF SEWER HYDRAULICS NOTE_ THE GIVEN FLOW DEPTH -TO -SEWER SIZE RATIO= .9 ----- ------------------------------------------------------------------- SEWER MAMHOLE NUMBER SEWER REQUIRED SUGGESTED EXISTING FD NUMBER UPSTREAM DNSTREAM SHAPE DIA(RISE).DIA(RISE) DIA(RISE) WIDTH ID NO. --------- ---------------------------------------------------------------------- ID NO. (IN) (FT) (IN) (FT) (IN) (FT) (FT) 20.00 10.00 ROUND 15.29 18.00 18.00 0.00 '100.-00 . 200.00 30.00 20.00 ROUND 9.24 = 15.00 0.00 0.00 300.00 40.00 30.00 ROUND 9.24 15.00 0.00 0.00 301.00 41.00 ' 302.00 42.00 40.00 40.00 ROUND ROUND 5.32 5.22 15.00 15.00 0.00 0.00 0.00 0.00 101.00 21.00 20.00 ROUND 14.59 15.00 0.00 0.00 400.00 50.00 10.00 ROUND 14.59 15.00 18.00 0.00 ' 401.00 51.00 50.00 ROUND 14.59 15.00 18.00 0.00 DIMENSION UNITS FOR ROUND AND ARCH SEWER ARE IN INCHES MENSION UNITS FOR BOX SEWER ARE IN FEET QUIRED DIAMETER WAS.DETERMINED BY SEWER. HYDRAULIC CAPACITY. GGESTED DIAMETER WAS DETERMINED BY COMMERCIALLY AVAILABLE SIZE. VOR A NEW SEWER, FLOW WAS ANALYZED BY THE SUGGESTED SEWER SIZE; OTHERWISE, ISITNG SIZE WAS USED 1:L f SEWER DESIGN f MMENT ID FLOW Q NUMBER CFS '100.0 7.4 200.0 0.9 300.0 0.9 '301.0 0.4 302.0 0.4 101.0 6.5 400 0 6 5 ----------------------------------------------------------- FLOW NORMAL NORAML CRITIC CRITIC FULL FROUDE FULL Q DEPTH VLCITY DEPTH VLCITY CFS --------------------------------------- FEET FPS FEET FPS 11.4 0.88 6.86 1.06 5.50 3.1 0.45 2.18 0.38 2.75 3.1- 0.45 2.18 0.38 : 2.75 7.0 0.21 3.19 0.28 2.14 7.0 0.21 3.14 0.28 2.08 7.6 0.95 6.49 1.02 6.04 VLCITY NO. FPS --------------------- 4.16 1.42 V-OK 0.70 0.67 V-LOW 0.70 0.,67 V-LOW 0.36 1.46 V-OK .0.34 1.46 V-OK 5.30 1.18 V-OK '11.4 0.81 6.67 0.98 5.29 3.68 1.46 V-OK 401.0 6.5 11.4 0.81 6.67 0.98 5.29 3.68 1.46 V-OK FROUDE NUMBER=O INDICATES THAT A PRESSURED FLOW OCCURS '--------------------------------------------------------------------- SEWER SLOPE. INVERT ELEVATION BURIED DEPTH COMMENTS NUMBER UPSTREAM DNSTREAM UPSTREAM DNSTREAM 'ID ---------------------------------------------------------------------- % (FT) (FT) (FT) (FT) ' 100.00 200.00 1.00 0.20 64.61 64.64 63.84 64.61 2.09 2.81 3.16 2.34 OK 300.00 0.20- 65.10 64.63 3.65 2.82 OK .. OK 301.00 1.00 65.13 65.12 3.22 3.63 OK '302.00 1.00 65.31 65.30 3.44 3.45 OK 101.00 1.00 64.88 64.87 2.07 2.08 OK 400.00 1.00 63.89 63.72 2.81 3.28 OK 1.00 63.90 63.89 2.80 2.81 OK �401.00 C MEANS BURIED DEPTH IS GREATER THAN REQUIRED SOIL COVER OF 1 FEET 1 I 1 1 F L 1** SUMMARY OF HYDRAULIC GRADIENT LINE ALONG SEWERS SEWER ID NUMBER 100.00 200.00 300.00 ' 301.00 302.00 ' 101.00 400.00 401.00 -------------------------------------------------------------------- SEWER SURCHARGED CROWN ELEVATION WATER ELEVATION FLOW LENGTH LENGTH UPSTREAM DNSTREAM UPSTREAM DNSTREAM CONDITION FEET FEET FEET FEET FEET FEET 77.00 0.00 66.11 ------------------------------------ 65.34 65.67 65.22 JUMP 15.00 15.00 65.89 65.86 66.41 65.67 PRSS'ED 233.00 233.00 66.35 65.88 66.44 66.41 PRSS'ED 1.00 1.00 66.38 66.37 66.45 66.44 PRSS'ED 1.00 0.00 66.56 66.55 66.45 66.44 JUMP 1.00 0.00 66.13 66.12 66.04 65.67 JUMP 16.50 0.00 65.39 65.22 65.02 65.22 JUMP 1.00 0.00 65.40 65.39 65.18 65.02 JUMP �RSSIED=PRESSURED FLOW; JUMP=POSSIBLE HYDRAULIC JUMP; SUBCR=SUBCRITICAL FLOW *** SUMMARY OF ENERGY GRADIENT LINE ALONG SEWERS --------------------------------------------------------------------------- UPST MANHOLE SEWER JUNCTURE LOSSES DOWNST MANHOLE '-ID SEWER MANHOLE NO ID NO. ENERGY ELEV-FT------FT FRCTION BEND K COEF BEND LATERAL LATERAL LOSS FT K MANHOLE ENERGY ------------ --- ------------------------------------------------ COEF LOSS FT ID FT 100.0 20.00 66.14 0.92 0.50 0.00 0.50 0.00 10.00 65.22 t200.0 30.00 66.41 0.00 0.50 0.00 0.50 0.27 20.00 66.14 300.0 40.00 66.45 0.03 0.50 0.00 0.00 0.00 30.00 66.41 301.0 41.00 66.45 0.00 0.50 0.00 0.00 0.00 40.00 66.45 42.00 66.45 0.00 0.50 0.00 0.00 0.00 40.00 66.45 '302.0 101.0 21.00 66.47 0.12_ 0.50 0.22 - 0.00 0.Go 20.GO 66.14 400.0 50.00 65.23 0.01 0.50 0.00 0.00 0.00 10.00 65.22 ' 401.0 51.00 65.39. 0.06 0.50 0.11 0.00 0.00 50.00 65.23 BEND LOSS =BEND K* FLOWING FULL VHEAD IN SEWER. LATERAL LOSS= OUTFLOW FULL VHEAD-JCT LOSS K*INFLOW FULL VHEAD 'FRICTION LOSS=O MEANS IT IS NEGLIGIBLE OR POSSIBLE ERROR DUE TO JUMP. FRICTION LOSS INCLUDES SEWER INVERT DROP AT MANHOLE NOTICE: VHEAD DENOTES THE VELOCITY HEAD OF FULL FLOW CONDITION. MINIMUM JUCTION LOSS OF 0.05 FT WOULD BE INTRODUCED UNLESS LATERAL K=O. 'A FRICTION LOSS WAS ESTIMATED BY BACKWATER CURVE COMPUTATIONS. 1 mf SPILLWAY/ WEIR DESIGN Weir Equation Q = C L (H) ^ 2/3 Q (cfs), C (weir coefficient), L (crest length, feet), H (energy head, feet) See Table 704 in this Report for C factors 2 = Weir Length H feet 3.1 = Weir Coefficient C Weir Shape Spilway Pond #1, Lot 18,19 Design Flow 0.44 . (cfs) Depth of flow H ft Flow Over Weir Q cfs 0.10 0.20 0.11 0.23 0.12 0.26 0.13 0.29 0.14 0.32 0.151 0.36 0.16 0.40 0.17 0.43 0.18 0.47 0.19 0.51 taxv, z-4'r L Uct-VIn+ -!5FI I,&- W A`( �'ix I L DETENTION DESIGN INFORMATION FOR EVERGREEN PARK LOTS 179 189 19 1 DETENTION POND SIZING BY FAA METHOD ' Developed by Dr. James Guo, Civil Eng. Dept., U. of Colorado Supported by Denver Metro Cities/Counties Pool Fund Study Denver Urban.Drainage and Flood Control District, Colorado ISER=Stewart and Associates -Ft Collins Colorado .............................. EXECUTED ON 02-14-1995 AT TIME 07:54:40 PROJECT TITLE: Evergreen Park Phase #1 I*** DRAINAGE BASIN DESCRIPTION BASIN -ID NUMBER = 1.00 BASIN AREA (acre)= 1.33• RUNOFF COEF 1.00 DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD (YEARS) = 100.00 INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN 'DURATION 5 10 20 30 40, 50 60 80 100 120 150 180 'INTENSITY 9.0 7.5 5.2 4.2 3.5 3.0 2.6 2.1 1.7 1.5 1.2 1.0 ***** POND OUTFLOW CHARACTERISTICS: ' MAXIMUM ALLOWABLE RELEASE RATE _ .44 CFS OUTFLOW ADJUSTMENT FACTOR = 1 AVERAGE RELEASE RATE .44 CFS. ' AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. J 0 J 5 I DETENTION POND PHASE 1 HIGH WATER LINE I I I I I I I I I I I I VOL. = 1/3 (AREA ABOVE) (DIFFERENCE IN COUNTOUR ELEV.) 2. FOR THE REMAIMOER OF THE VOLUMES BETWEEN CONTOURS (SECTION 9.2) VOL. = DEPTH/6 (A + 4AB mean + B) 3. HWL= (VOL.REQ. —VOL. LOW CUML)*6/(AREA LOW+4*AVG.AREA+AREA HIGH) ORIFICE SIZING ORIGINAL DESIGN DATA 0.44 = Allowable Des. Release Rate(cfs) NOTE: 1. HORZ. PLATES WILL BE PLACED 6' 65.00 = Flowline Orifice Elevation(ft) BELOW GRATE 0.65 = Orifice Coefficient (Cd) 2. VERT. PLATES WILL BE PLACED 4.63 = Avaliable Driving Head(ft) AT PIPE FLOWLINE VERT. CIRCULAR PLATE Si72 Outlet Area inches ........ .. ... ... ... ....... ...... . ..... Davin s inches ........... 4.5t:�� AdtbAIiHV&auIic:Drivinq Head 11 VERT. SQUARE PLATE 11 .1 -Lol, COMPUTATION.OF POND SIZE RAINFALL ---------------------------------------- RAINFALL INFLOW OUTFLOW REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE MINUTE- INCH/HR ACRE -FT ACRE -FT ACRE -FT -- 0.00 0.00 0..00 0.00 0.00 5.00 9.00 0.08 0.00 0.08 10.00 7.50 0.14 0.01 0.13 15.00 6.35 0.18 0.01 0.17 20.00 5.20 0.19 0.01 0.18 ' 25.00 30.00 4.70 4.20 0.22 0.23 0.02 0.02 0.20 0.21 35.00 3.85 0.25 0.02 0.23 40.00 3.50 0.26 0.02 0.23 ' 45.00 3.25 0.27 0.03 0.24 50.00 3.00 0.28 0.03 0.25 55.00 2.80 0.28 0.03 0.25 60.00 2.60 0.29 0.04 0.25 ' 65.00 2.47 0.30 0.04 0.26 70.00 2.35 0.30 0.04 0.26 75.00 2.22 0.31 0.05_ 0.26 80.00 2.10 0.31 0.05 0.26 85.00 2.00 0.31 0.05 0.26 90.00 1.90 0.32 0.05 0.26 95.00 1.80 0.32 0.06 0.26 100.00 1.70 0.31 0.06 0.25 105.00 1.65 0.32 0.06 0.26 ------------------------------------------------- THE REQUIRED POND SIZE _ .2628007 ACRE -FT 'THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 75 MINUTES ----------- DETENTION POND POND SIZING BY FAA METHOD ' Developed by Dr. James Guo, Civil Eng. Dept., U. of Colorado Supported by Denver Metro Cities/Counties Pool Fund Study Denver Urban Drainage and Flood Control District, Colorado ER=Stewart and Associates -Ft Collins Colorado .............................. EXECUTED ON 10-25-1994 AT TIME 14:34:21 'PROJECT TITLE: Evergreen Park Phase 2 ** DRAINAGE BASIN DESCRIPTION BASIN ID NUMBER = 2.00 ' BASIN AREA (acre)= 1.18• RUNOFF COEF 0.91 DESIGN RAINFALL STATISTICS DESIGN RETURN PERIOD (YEARS) = 100.00 INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN LRATION 5 10 20 30 40 50 60 80 100 120 150 180 FNTENSITY 9.0 7.5 5.2 4.2 3.5 3.0 2.6 2.1 1.7 1.5 1.2 1.0 ***** POND OUTFLOW CHARACTERISTICS: ' MAXIMUM OUTFLOW ALLOWABLE RELEASE RATE ADJUSTMENT FACTOR _ .42 = 1 CFS AVERAGE RELEASE RATE _ .42 CFS ' AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR. ' ***** COMPUTATION OF POND SIZE ' --------------------------------------------- RAINFALL RAINFALL INFLOW OUTFLOW ---- REQUIRED DURATION INTENSITY VOLUME VOLUME STORAGE .. MINUTE INCH/HR ACRE -FT ACRE -FT ACRE -FT --- 0-.00--------- -00 ------- --------- 0 0-00 0-.00--------- 0-.00-- 5.00 9.00 0.07 0.00 0.06 10.00 7.50 0.11 0.01 0.11 ' 15.00 6.35 0.14 0.01 0.13 20.00 5.20 0.16 0.01 0.14 25.00 4.70 0.18 0.01 0.16 30.00 4.20 0.19 0.02 0.17 35.00 3.85 0.20 0.02 0.18 40.00 3.50 0.21 0.02 0.19 t 45.00 3.25 0.22 0.03, 0.19 50.00 3.00 0.22 0.03 0.19 55.00 2.80 0.23 0.03 0.20 60.00 2.60 0.23 0.03 0.20 ' 65.00 2.47 0.24 0.04 0.20 70.00 2.35 0.25 0.04 0.20 75.00 2.22 0.25 0.04 0.21 '. 80.00 2.10 0.25 0.05 0.20 85.00 2.00 0.25 0.05 0.26 90.00 1.90 0.26 0.05 0.20 ' 95.00 1.80 0.26 0.05 0.20 100.00 1.70 0.25 0.06 0.20 105.00 1.65 0.26 0.06 0.20 k--------------------- ---------------------------- HE REQUIRED POND SIZE _ .2054871 ACRE -FT THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= GEOMETRIES OF AN EQUIVALENT CIRCULAR POND ---- --------------- STAGE CONTOUR, (DEPTH) DIAMETER ---------- FEET FEET 0.00 105.32 0.50 109.32 ' 1.00 113.32 1.50 117.32 2.00 121.32 ' 2.50 125.32 ------------------- 1 ---------------------------- CONTOUR POND POND AREA SIDE SLP STORAGE ACRE ---------------------- FT/FT ACRE -FT 0.20 4.00 0.00 0.22 4.00 0.10 0.23 4.00 0.22 0.25 4.00 0.34 0.27 4.00 0.46 0.28 4.00 0.60 75 MINUTES IAO 00 ., O III � O U o �- y 9 � O O +� O w 14 O 0 ro w o a) �► A. . 4-J W � ro 0 � ar 41 ro D A"' J4 3 m' O 44 w V V 0 O D, N 7 _ J 03 � r `- 00 CD � N Q7 00 CD d N 00 CF) CY) C D0 00 00 00 O CD O O O O O O x — .10-0s,3 quaui-snrpv Aioulnp L�� 1 EXHIBITS FOR . EVERGREEN PARK LOTS 179 189 19 I 4 ADCA *!O 6.7 1 AREA IAREA'w6 Iso !Ac-Ft• " 7 Di H •-� LN 3 c F J e 20 ��p(ON ti 20 *3A AREA I i I AREA I AREA ' no WILLOX 21s 217 W �" Northerly Q 01efj Release Point a BRISTLECONE' DR. I 201 — c —...__ L..T_.� tie ` __M ---- W oa' � vo�a AREA �4 AREA "2 AREA "OA -' 105 220 CONIFER SIT. �L3 � Q 101 b Ac-Ft ! CONIFER ST. _ 7 4 9.5 210 _. Ac-Ft `t=s' t AC-1 200 33 aiterly Release 21a AREA 120 Point "5 AREA "OB N N cj Ac —Fl, fIII W 150 1 � SCALE: I°= 800' ,,.—Southerly Release Point 205 �`.. DRY _CR� I NOTES: 1) SHAPE a SURFACE AREA OF PONDS APPROXIMATE ONLY. 2) POND NUMBERS ARE SAME AS BASIN NUMBERS. LEGEND BASIN . BOUNDARY STORM SEWER OR CULVERTS 123 OPEN CHANNEL W/CONVEYANCE CODE USED IN TABLE 1. C DETENTION PONDS oW(aIpkc 1981 tXAl31T 'I �S TITLE EVERGREEN PARK FIGURE 2 FINAL DRAINAGE PATTERN I I hI ILJ TM, CtfA W �FCIL-VE�:2-I`i�-95 S.D.vru:�, development. Storm runoff is conveyed overland east and northeast to the Lake Canal and the northeast corner of the site, near the location of the proposed outlet for the Evergreen East Pond. tBasin 1. With the exception of a cul-de-sac and single house in its northwest corner, he basin is undeveloped with most of the central and west -central portion of the basin being comprised of a wetland. For modeling purposes, the basin was divided into Basins 1A through 1D to.reflect both the obstructions formed by Willox Lane and Bramblebush Street, and the disparity in projected land use. The southeast corner (Basin 1D) and the northern portion (Basin 1A) of the basin are slated for development at medium and low density residential levels. In the eastern portion of the basin (Basin 1C), the City is currently planning construction of the new Greenbriar Park. The western portion of the basin (Basin 1B) consists of a wetland and an upland area directly to the north of the wetland. Storm runoff is currently conveyed via overland flow, and storm sewer across Willox Lane, to the wetland which is the low point in the basin. pipes Basin 2. The basin is mostly undeveloped with one commercial development and an REA substation located in the southern half of the basin; the basin is zoned for a combination of commercial, and both high and low density residential development. Storm runoff is conveyed via streets, and storm sewer pipes across Conifer Street, to the existing Redwood Pond (formerly Pond 2). This pond is complete (as designed) with the exception of an outlet device. Basin 3A. - The basin is essentially undeveloped with the exception of the single commercial operation along College Avenue; the basin is zoned entirely for commercial development. Storm runoff is conveyed along streets, and in the existing storm sewer system along Bristlecone Drive and across Blue Spruce Drive, to the existing inlet channel for the Evergreen West Pond (formerly Pond 3) located east of Blue Spruce Drive. Basin 3B. The basin is approximately half developed with a combination of commercial and medium density residential land use; the basin zoning includes 31 and 57 percent of each of these land uses, respectively,'with the remaining 12 percent of the basin being zoned for high and low density residential housing. Stone runoff is primarily carried in streets, and the existing storm drainage channel/culvert system along the east side of Blue Spruce Drive, to the existing Evergreen West Pond inlet channel. The Evergreen West Pond is an existing facility which is characterized by incomplete earthwork/berming and the lack of an outlet device. Basin 4. The basin is 41 percent developed with commercial areas concentrated along College Avenue and sparsely dispersed throughout the rest of the basin; it is zoned entirely for commercial land use. Due to the lack of favorable topography for providing on -site detention in the existing commercial areas, or a major detention pond within the basin, this basin was conceptually divided into Basins 4D and 4U representing developed and undeveloped areas, respectively. Storm runoff is conveyed along streets, and in the .partially completed storm sewer system along Conifer Street, to the rough -graded drainage channel south of Conifer Street in Basin 5. a% LJE ARE i>it0'ibi�t5 fk�S(TE DcT>=i�Tlq•� �e -I}ylt, o��C r 5 as Basin 5. The basin is entirely undeveloped but is zoned exclusively for commercial use. The basin was divided into Basins 5A and 5B for the areas located west and east, respectively, of the aforementioned drainage channel south of Conifer Street. Storm runoff currently flows overland to the drainage channel (from Basin 5A), and to Dry Creek at the southeast comer of the basin (from Basin 5B). ' Basin 6. The basin is primarily undeveloped with only a small percentage of medium density residential and commercial development; it is slated to be developed primarily for ' commercial use, and small percentages of both medium density residential and open space areas. The open space is associated with the existing wetland (which is functioning as a stormwater detention pond) along Willox Lane; the existing wetland encompasses a ' relatively large portion of the basin which may preclude the extent of commercial development indicated by the current land use maps. Storm runoff currently flows overland to the low-lying wetland area (Pond 6) adjacent to Willox Lane. The pond has ' an existing outlet pipe which discharges'to the previously identified channel along Blue Spruce Drive. In addition, this area is served by a subdrain which crosses Basin 3B, drains southerly along Redwood Street, and ultimately outlets to the Lake Canal. ' Basin 7. The basin is mostly undeveloped with less than 15 percent of the area in ' medium density residential use; the basin is zoned for 80 percent medium and low density residential housing, and 20 percent commercial development. The basin has been subdivided into Basins 7A and 7B to reflect the presence of a small ridge north of ' Spaulding Lane which separates the northern and southern portions of the basin. In general, runoff is conveyed overland to the Larimer and Weld Canal which forms the southern boundary of the basin. Storm runoff from the basin currently enters the ditch ' within this basin. Basin 8. The basin is comprised of Basins 6A and 8 as defined in the Evergreen Park Master Plan [EPI, 1981]. The northern half of the basin is mostly undeveloped, while the southern portion of the basin exhibits high to low density residential development and a small area of commercial development near the western basin boundary. The runoff ' pattern is generally northeast to southwest with all runoff being intercepted by the Larimer and Weld Canal. As specified above, all runoff from this basin is considered to be exported from the Greenbriar-Evergreen Basin via the canal. ' Basin 9. The eastern portion of the basin (east of Ford Lane) is mostly developed with medium density residential use. West of Ford Lane, the basin is primarily undeveloped ' but is zoned for medium residential housing. The existing drainage pattern is generally east to west with runoff collecting in a large low area east of Highway 1. The basin is ' currently non-contributing to the Greenbriar-Evergreen Basin south of the Larimer and Weld Canal. A proposed residential development for the area west of Ford Lane would increase runoff from. the basin and direct flow southwesterly toward the canal. ' Crestview Basin (CV). The basin is located north of Country Club Road and is entirely developed with low density residential housing. The flow pattern is generally north to ' south with runoff being conveyed both overland and along streets. Country Club Road creates a significant hydrologic boundary; consequently, runoff concentrates along the ' 6 Table 3.3. Summary of Results for the Existing Condition Hydrologic Analysis iN. . Itugoff Release Rath OA 114 51.10 34 0.67 OB 113� 48.46 12 025 IA 120 13.97 15 1.07 1B 121 14.05 4 0.28 Ic 122 - 8.02 4 0.50 ID 123 3.01 4 1.33 2 112 49.14 17 0.35 3A 103 19.29 9 0.47 3B 104 69.16 63 0.91 4D 124 25.06 45 1.80 4U M 36.11 17 0.47 5A 126 12.55 5 0.40 5B 127 30.82 11 0.36 6 102 36.34 17 17 cfsa 7A 129 23.53 12 0.51 7B 101 42.91 16 0.37 8 105 42.95 43 1.00 9 107 21.95 10 0.46 CV 130 40.16 42 1.05 GBE 111 43.33 29 0.67 GBOE 109 13.85 11 0.79 NAV 115 69.30 13 0.19 PVE-A 116 23.00 11 0.48 PVE-B 117 43.93 22 0.50 PVW-A 110 4.76 3 0.631 1 PVW-B 1 108 11.48 7 1 0.61 Unit runoff not applicable; allowable release includes effects of regional detention and future condition inflows from Basins 7A, 713 and 9. , V1, d 1 storm runoff would be transported to the existing Evergreen West Pond. Outflow from this pond would enter the existing outlet channel which would transport flow southerly to. Pond 5 (conceptual). Basin 4D. By definition, the basin is currently fully developed for commercial use; the amount of impervious area for the basin was determined to be 97 percent. Due to the fully -developed condition of these portions of Basin 4, on -site detention is not feasible. Storm runoff would be conveyed to Pond 5 (conceptual). Basin 4U. The basin was assumed to be completely developed for commercial use with an estimated imperviousness of 90 percent. On -site detention would be required for this basin. The allowable release from this basin is 17 cfs, or 0.47 cfs/acre. The designated release point for Basin 4U is the storm sewer and street along Conifer Street which convey flows easterly to Pond 5 (conceptual). The detention volume required for the basin, in order to meet the prescribed release rate, was estimated to be 6.4 acre-feet. Basin 5A. The basin was assumed to be completely developed for commercial use with ' an estimated imperviousness of 90 percent. On -site detention would be required for this basin. The allowable release from this basin is 5 cfs, or 0.40 cfs/acre. The designated release point for Basin 5A is Pond 5; this pond would release flows to Dry Creek. The detention volume required for the basin, in order to meet the prescribed release rate, was estimated to be 2.3 acre-feet. Basin 5B. The basin was assumed to be completely developed for commercial use with an estimated imperviousness of 90 percent. On -site detention would be required for this basin. The allowable release from this basin is 11 cfs,-or 0.36 cfs/acre. The designated release point for Basin 5B is Dry Creek at the southeast corner of the basin. The detention volume required for the basin, in order to meet the prescribed release rate, was estimated to be 5.6 acre-feet. Basin 6. The basin was assumed to be primarily developed for commercial use (79 percent), with 8 percent devoted to medium density residential housing. The remaining 13 percent was assumed to be open space associated with existing wetland, which is. functioning as a detention pond. (It is noted that 13 percent is probably a conservatively low estimate of the wetland area within this basin.) The resulting estimated average imperviousness is 75 percent. On -site detention would be required for this basin. The allowable release from this basin is 17 cfs; however, the existing pond and outlet would limit the developed condition 100-year release to 12 cfs. It is not appropriate to define an allowable unit release, as the wetland area is slated to provide "regional detention" for off -site runoff emanating from Basins 7A, 7B and 9. The designated release point for Basin 6 is the upstream end of the Blue Spruce Drive roadside channel/culvert system which conveys flow to the Evergreen West Pond. The detention volume required for the basin, based on the current release rate of 12 cfs, was estimated to be 15.5 acre-feet. Basin 7A. The basin was assumed to be fully developed with medium and low density residential housing at 32 and 68 percent, respectively. Consequently, the estimated 20 u� I 1 1 1 EASEMENT DEDICATION PF—Tevi-110'— �AScM�FJ�T t�►ihs I / 1 KNOW ALL MEN BY THESE PRESENTS: That the undersigned being the owners of Lots 18 and 19, Block 3, Replat (No. 1), Evergreen Park, City of Fort Collins, County of Larimer, State of 1 Colorado do hereby dedicate and convey to and for public use forever a drainage easement, provided however, that acceptance by the City of Fort Collins of this dedication of easement does 1 not impose upon the City a duty to maintain the easement so dedicated. 1 A drainage easement situate in Lots 18 and 19, Block 3, Replat (No. 1), Evergreen Park, City of Fort Collins, County of Latimer, State of Colorado, which begins at the Southeast 1 corner of said Lot 18 and run thence South 100.00 feet; thence West 172.00 feet; thence North 25.00 feet; thence East 120.00 feet; thence N 30' 00' 00" E 23.09 feet; thence North 92.00 feet; thence West 15.00 feet; thence North 53.00 feet; thence East 55.45 feet; 1 thence South 90.00 feet to the point of beginning. 1 Witness our hands and seals this_ day of , A.D. 1995. By: 1 Bill Gillett, owner State of Califoruia)SS ' County of Orange) The foregoing instrument was acknowledged before me this _ day of , A.D. 19_ 1 by 1 Witness my hand and official seal. Notary Public 1 My notarial commission expires: 1 ATTORNEY'S CERTIFICATE This is to certify that on the of , A.I. 19_1 1 examined the title to the 1 property hereon described and established that the owners and proprietors of record of said property as construed in C.R.S. 1973, 31-23-111, are as shown hereon as of said date. Signature: Address: Registration No.. EASEMENT DEDICATION KNOW ALL MEN BY THESE PRESENTS: Thnat the undersigned being the owners and proprietors of the following described land do hereby dedicate and convey to the owners of Lots 18, Block 3, Replat (No.1), Evergreen Park, City of Fort Collins, County of Larimer, State of Colorado, an easement for grading purposes only, situate in the West 1/2 of Section 1, Township 7 North, Range 69 West of the 6th P.M., City of Fort Collins, County of Larimer State of Colorado, which begins at a point which bears North 2489.00 feet along the West line of said Section 1 and again East 215.00 feet from the Southwest corner of said Section I and run thence . North 463.00 feet along the West line of a.20.00 foot alley; thence West 3.00 feet; thence South 172.00 feet; thence East 0.50 feet; thence South 201.00 feet; thence East 1.70 feet; thence South 90.00 feet; thence East 0.80 feet to the point of beginning. This easement is for the period of one year, expiring on April 30) 1996. Prior to expiration of the easement and conclusion of the grading, the owner of Lots 18 and 19 will restore the surface of the land in the easement to its preconstruction condition. , Witness our hands and seals this _ day of , A.D. 1995. By: State of Colorado ). County of Latimer) ' The foregoing instrument was acknowledged before me this _ day of , A.D. 19_ by Witness my hand and official seal. ' Notary Public My notarial commission expires: ' ATTORNEY'S CERTIFICATE This is to certify that on the of , A.D. 19_91 examined the title to the property hereon described and established that the owners and proprietors of record of said property as construed in C.R.S. 1973, 31-23-111, are as shown hereon as of said date. Signature: Address: Registration No. EASEMENT DEDICATION KNOW ALL MEN BY THESE PRESENTS: That the undersigned being the owners of Lots 20, Block 3, Replat (No.1), Evergreen Park, City of Fort Collins, County of Larimer, State of Colorado do hereby dedicate and convey to and for public use forever a drainage and utility easement, provided however, that acceptance by the City of Fort Collins of this dedication of easement does not impose upon the City a duty to maintain the easement so dedicated. A drainage and utility easement being the West 9.00 feet of the East 15.00 feet of Lot 20, Block 3, Replat (No. 1), Evergreen Park, City of Fort Collins, County of Larimer, State of Colorado. Witness our hands and seals this _ day of , A.D. 1995. By: State of Colorado ),,, County of Larimer) The foregoing instrument was acknowledged before me this _ day of , A.D. 19_ by Witness my hand and official seal. Notary Public My notarial commission expires: ATTORNEY'S CERTIFICATE This is to certify that on the of , A.U. 19_1 I examined the title to the property hereon described and established that the owners and proprietors of record of said property as construed in C.ILS. 1973, 31-23-111, are as shown hereon as of said date. Signature: Address: Registration No. EASEMENT DEDICATION KNOW ALL MEN BY THESE PRESENTS: That the undersigned being the owners and proprietors of the following described land do hereby dedicate and convey to the owners of Lot 19, Block 3, Replat (No. 1), Evergreen Park, Fort Collins, Colorado, an easement for grading purposes only, situate in the West 1/2 of Section 1, Township 7 North, Range 69 West of the 6th P.M., City of Fort Collins, County of Larimer, State of Colorado, being the North 5.00 feet and the West 5.00 feet of Lot 20, Block 3, Replat (No. 1), Evergreen Park. This easement is for the period of one year, expiriug on April 15, 1996. Prior to expiration of the easement and conclusion of the grading, the owner of Lot 19 will restore the surface of the land in the easement to its preconstruction condition. Witness our hands and seals this _ day of , A.D. 1995. State of Colorado)„ County of Larimer) The foregoing instrument was acknowledged before me this _ day of , A.D. 19_ by Witness my hand and official seal. Notary Public My notarial commission expires: ATTORNEY'S CERTIFICATE This is to certify that on the of , A.D. 19_, 1 examined the title to the property hereon described and established that the owners and proprietors of record of said property as construed in C.R.S. 1973, 31-23-111, are as shown hereon as of said date. Signature: Address: Registration No. - <.. NATIONAL FLOOD INSURANCE PROGRAM FIRM FLOOD INSURANCE RATE MAP CITY OF FORT COLLI.NS, COLORADO LARIMER COUNTY PANEL 2 OF 1 . (SEE MAP INDEX FOR PANELS NOT PRINTED)'' - V C> tA. of ( e 0 n. /u, (4:��P yG... f COMMUNITY -PANEL NUMBER 080102 0002 B MAP.REVISED: aN� c� o t•� Federal KEY TO MAP ear Flood Boundary F.:-0::;ZONE B ear Flood Boundary Designations' With f Identification n In In ' • car Flood Boundary •_--..._..-.- - r r ear Flood Boundary lood Elevation Line 513 levation In.Feet+• load Elevation in Feet ' (EL 987) Uniform Within Zone** ion Reference Mark . RM7x D Boundary.. ... —'•� Mite. • M 1.5 ercriced to the. National Geodetic Veriical Datum of 1929 XPLANAT,ION OF ZONE. DESIGNATIONS FEBALIARY.,1:5,f I' i • t .t <If '.w•cf�:r5..� v a,h �f'� EXPLANATION Areas of 100-year flood; base flood elevations and flood hazard factors not determined. Areas of 100-year shallow flooding where depths are between one (1) and three (3) feet; average depths of inundation are shown, but no flood hazard factors are determined. .,Areas of 100-year shallow flooding where depths are between one (1) and three (3) feet; base flood elevations are shown, but no flood hazard factors are determined. 10 Areas of 100-year flood; base flood elevations and flood hazard factors determined. Areas of. 100-year flood to be protected by flood protection system under construction; base flood elevations and flood hazard factors not determined. Areas between limits of the 100-year flood and 500- year flood; or certain areas subject to 100-year flood- ing with average depths less than one (1 ) foot or where the contributing drainage area is less'than one square mile; or areasprotected by levees from the base flood. (Medium shading) Areas of minimal flooding. (No shading) Areas of undetermined, but possible, flood hazards. Areas of 100-year coastal flood with velocity (wave action); base•flood elevations and flood hazard factors not determined. 10 Areas of .1007year coastal flood with velocity (wave action); base flood elevations and flood•hazard factors "determined.: NOTES TO USER i areas.not in the'spe6al flood hazard areas (zones A and, V) protected by flood control structures. iap is for. (foodinsurancepurposes only; it does not neces- show all areas subject to flooding in the community or IIimetric features outside special flood hazard areas. (Joining map panels,.,see separately printed Index To Map INITIAL IDENTIFICAI ION: .JUNE 28, 1974 FLOOD HAZARD BOUNDARY MAP REVISIONS: 7N 4r . . . . . . . ..... -lq va c - A ..'.j. SEU .11 MFl NEW DRIVEWAY APPROACH DETAILS Me AW WT TER all JXA _ -- �s/er /'• 30' f i p JIB 1f2 I EL 5 o. zekl cm• v- y 1AtLL i I I I CI.� I 1 to