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Home My WebLink AboutGrading Plans - 04/17/2020conr�c-r u�Foav��oN JORDA� pL�ER�.1A�lN 01Y\ER/C ESIG��ER FORCE + BOu! DVlEWNGS �; ORDAN'�°f ORGEr,tiDBOW.cO V +1 i970) 417-9777 t 7 G � 7. COL1_EGE A��E FOR7 COLLINS, CCLORADO �4�V1V. FO RC E4NC 801Y. CO M :99RPrILTI�N IFr,F":fl �� . ; � �„ . I � _ . ' xi �Te r-��c=er:Tv u�.e ``��- StkJETHACK �'_,_ ^�4 ��'^ ; , IFTP.'dEfi I?ETaPJ:,; �,�.LL p , � < <�j�,:� /' �dl": HEIGHT i�:/ �., fi. � �/ � -__ 4995.3 • . � �': � .. ,. :��-;�- - FL � Accepted 4/17/2Q20 WL �37 SHERYIOOD SiREET EXISTINC '�.ESL�EhTIsL --- �°9n' ��- ��'I�.-',- /� . .. � . . � 1994.9 F =� �..E-- � ..�" �-'-Fi �� . � �� n:- �. � % g��! � :�9: - _ . � . 1� , ' r- FL 'I / ! G , � _ - I F , � -I � �.. ' . . , f , � � � / � �. . . ;..E t.. - 1 �o_� ;2 _ —t'?.-�j_ — — -��?��—{ � � x-- � ,'f >.E7b�CK. �— j� .-�i'-F �i. Ly .�. -,I-',L }-- �_ . _�} _�_.._ x � . . 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PRCTECT EXISTI�v� T!tEES IN FLACE. �. i0P OF FOUNCr710N fdUST 6E �T LEaST o�' :,6C`,�E 1HE HICHEST CS2ACE SURROUNDINC :iLL ��Jl01tvGS. 5. 1HE�E ti<UST BE k NIk11.1U�+ Ga,aDE CF 5% aw�Y FROM THE FUILIiINGS V�ITHIN THE FIRST 5 TO 70 FEEi :.O.;.aCENT "f0 THE RE`IDE�CE. 5. :.LL SLOrES i•IUST NEET' iHE �.9NINU�.� REOUIREMEhT LF i% �.NO tiRE NCT TO DE 5TEE�'ER THAN 33 0(3�?). � �,lL CCNTRCI 5HeL1 DE '�ERIF�Ea 3� THE CONTRaCTCr< HEFORE r.NY CONSTRC(,'TIO�I OR O1NER I�.IPROVEf.iENTS. d�aizonr�i n�7.�.� NOCIFlEO �tiDG3/20i i CCLOR.aGO STf7E PLaNE COORCIhr.TE SYS1E1.1 NORiH ZONE SCFLE FaCTOR (0.99573814) 1.00A261?29 vE'TI�.:I -�PTUu CITr GF FOkT C�LLIN5 vEF+.11C�L LENCNn�aRK !-73 ELEyATION - �979 75 (N:,VD88 vERIIC:+L CrTU+A) NCTES: 1. 7W5 IS NCT h UNO SURvE" PIr.T OR I��PROVEIdENT SURb'E" FL:T. aLL LGT LIvES. r?IGHTS CF u�.�r >ND E;SEn�E��T LIvEs a�E 7C EE CONSI�Ei:EG apPRO>:I�+:.1E. 2. �LL CONTRCL SFI01vN SHtiLL BE vERIFIE� BY THE CONTRACTOR 6EFORE aNY CON57'�I;CTiCN OR (iTHER 16t PRO� �En� 6��TS. LE�Euc: b:i��a - 0 x Ao,9'� � � �l ��"�g X i% � _ I t— .. ExIS11N; C:CrIT� R PR�'GSEC C�r1T0uR PROPOSE: SPOT EIE�;:,11Cn ExIS11NG SaST ELE4'p110N �.eu PROP6SE�J E!_OFE s"`�"' <o�r . Aoc/t0 ENISIING S1D=E -.�•rs a�ri iot�i ii PROPOSEI CONCREIE EY�SIING CCNCRfiTE TO [E R£11G'�=ED PROP6SE6 FLD'hUNE =� PrtOPOSE; C07�NSPOUT ANO FLOW �IRECIIC� f- W � d 3 Q W _ N � O Z �pDO LICE I o�0��,...L .. ysF c,�:�p.N kF . O rg� �m't 39�78 ��-�� .��;,. ===-�Q 9G�� •.. �-:T \a�� f = 20' SSior,la�EN� Ad}yy� pd��d I AdjUsted Adfusted Che��e ln epeww�d rs,io�;c H��io�c K�sw,;� Hawn� oeveioom o�vewvee oe.eNom Derebped imantous /1�ea A(s�I Aret A(si� Mea B Isll �Ta � Is() Arei A IsQ Area A If�M �a 6If�) A�ea B(s/) Arca �t1� rm e��; ;�s s� s� ss � �s �io �,a c o o '�.�na i,3no ars � a�s 3.iw 3.�ae ,�;�,� ' o j o ( �« '�� o � o - o . o Da�Kn�;(40%) 720 I 284 C ' O O O O � O i n0Yrv1a�5A�ea B95 I i6Ti 2.298 570 I 570 3.698 . 3.H98 1.707 � EY:ISiING OtEFHE:�D ELECII�IC Ek1STING UNCE�GROUNO ELECTpIC�.L SER�;ICE EYISTING UFlLEiGft0UN0 GAS SEHvk'E �� Kmw wnan belo�v. Call eatare you aq. � I � � ��' - _� _= - -;. � �, � -- � �'; �!� .� ,� . • ��"�� ac�� February 26, 2020 Stormwater Engineering & Development Review Division City of Fort Collins Utilities 700 Wood Street Fort Collins, Colorado 80522 RE: 233 North Sherwood Street Drainage Memo Parcel # 9711129003 To Whom it May Concern: KEEFE CIVIL, LLC 825 Union Street Golden, Colorado 80401 (970) 215-6808 ineg@lceefecivil.com Keefe Civil Project Number: 2019-031 The purpose of this letter is to describe the proposed site improveinents and potential drainage impacts at 233 North Sherwood Street (Exhibit A). The 0.23 acre project site is a developed residential lot located on the west side of North Sherwood Street in Fort Collins, Colorado between Maple Street and Laporte Avenue. The lot is bound by existing residential properties to the north and south, gravel alley to the west, and North Sherwood Street right-of-way on the east. The existing site includes a single-story house, concrete sidewalks, landscape pavers, and gravel parking off the alley. The yard has sparse vegetation. According to the NRCS Soil Survey of Larimer County (Exhibit B), the site soils consist of Paoli fine sandy loam at 0 to 1% slopes. The soils have a rating of Group A, which indicates the soils have a high intiltration rate when thoroughly wet. Based on the flood insurance rate map (Exhibit C), the lot is located within Zone X. Zone X is defined as an area of minimal flood hazard and does not have a base flood elevation associated with it. However, the eastern portion of the lot is located within a City of Fort Collins moderate risk 100-year floodplain and the western portion of the lot is located within a City of Fort Collins high risk 100-year floodplain. Per a recent conversation with City of Fort Collins staff, the floodplain elevation at the back of ihe 1ot is 4994.4 ft. Historically, site stormwater has either drained into the alley (Historic Drainage Basin A) or from the west to the east into North Sherwood Street right-of-way (Historic Drainage Basin B). The southwestern properly corner is at an approXunate elevation of 4994.90 ft, which is only 0.5 ft higher than the southeast property corner, 190 ft away. There are also two existing low points in the topography west and southwest of the house. Based on survey completed in January 2020, the alley to the west does not have a consistent slope towards Maple Street and ponding has been witnessed in the a11ey west of the site (Exhibit E). The proposed site improvements include a two-story house addition with finished basement, a garage with access off the alley, concrete sidewalks, and a concrete patio. The proposed drainage patterns will remain consistent with existing conditions; however, site development will significantly improve drainage off the lot. The minimum garage slab elevation is proposed at -�: ,3 - 3 � 3 -� 3 -�: � T� rJ _ �;' G _ ,� t"i _ �� T� Q � II ' o a e� e e a e` 6 a� e e e e a a e e a e e a e e a a c a q v v a o a a v v a a v a a a a v a a a o v v a c ,°o°�,°o��°�,��o�'„ao°o°tr��oadDa�od�.�d�Q°Qno°o�G�oed� AAAG��AAAt�s�AG�G�AL�CsL�.AA�A.4,C�►�'A6 233 North Sherwood Street Drainage Memo Pa�e 2 of 2 Keefe Civil Project No.: 2019-031 February 26, 2020 4995.4 ft, which is one foot above the City of Fort Collins floodplain elevation. The total impervious area will increase 1,707 square feet (s� overall, but only 127 sf of the new impervious area total will be towards the alley. Adjusted Adjusted Historic Historic Historic Historic Adjusted Adjusted Change in Harclscape or Area A Area A Area B Area B Developed Developed Developed Developed Impervious Hard Surface (st� (sf� (sf� (s Area A sf� Area A(sf� Area B(sf� Area B(sf� Area (sf� Coucrete 175 175 890 890 95 95 710 710 Rooftop 0 0 1,300 1,300 475 475 3,188 3,188 Pavers (40%) 0 0 108 108 0 0 0 0 Gravel parl<ing �ZO 288 0 0 0 0 0 0 (40%) Total Impervious 895 463 2,298 2,298 570 570 3,898 3,898 1,707 A rea The composite runoff coefficient and drainage basin runoff calculations for the historic and developed site are included in the enclosed tables (E�ibit F). Using the Fort Collins Stormwater Criteria Manual, the historic and developed storn7water runoff estimates are as follows. 2-year 10-year 100-year Basin A Historic Runoff 0.04 cfs 0.06 cfs 0.16 cfs Basin A Developed Runoff 0.04 cfs 0.07 cfs 0.19 cfs Basin B Historic Runoff 0.11 cfs 0.19 cfs 0.52 cfs Basin B Developed Runoff 0.24 cfs 0.40 cfs 1.03 cfs Based on the enclosed design, it is my professional opinion the additional runoff generated by these site improvements will not cause adverse iinpacts to downstream private properties. I herby attest that this letter for the final drainage design for the 233 North Sherwood Street was prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed by others. Thank you for the opportunity to submit this drainage inemo. Please do not hesitate to reach out to me if you have any questions or comnlents regarding the above items. (970) 215-6808 or meg@keefecivil.com Best regards, Megan L. Keefe, PE / Manager Keefe Civil, LLC Enclosures � o�PDO LI�F� �\•' ��N,� •/t' :sFO . � cc . :�� m � : 39378 : . . � '•. .� �� o�,�..,. ., • ��, sSioNa� ��'�� Cc: Jordan Obermann, FORGE + BOW DWELLINGS : ��: ?� �3 �a Q� �� Qp �3 Q� �i3 ��. � o a e� e e a e- a a� e e" e e a a� e- e a e e a e e a a c a q v v a o a a v v a a v a c a a v a a a o v v a c ,°o°�,°o��°�,��o�'„ao°o°tr��oadDa�od�.�d�Q°Qno°o�G�oed� AAAG��AAAt�s�AG�G�AL�CsL�.AA�A.4,C�►�'A6 �I .,_ '' ��I '� :'' I � �II, r,9 I � . � �I �, ��" �� I � ' �c�99�91 li . , �< <z� ` \I �`9g�9� �i � �� E � y J /`, _— Q x � m (� � ABBREVIATION LEGEND: DS DWG EG EX FF FG FL FS GB GFF HP INV LP ROW DOWNSPOUT DRAWING EXISTING GROUND EXISTING FINISHED FLOOR FINISHED GRADE FLOWLINE FINISHED SURFACE (CONCRETE) GRADE BREAK GARAGE FINISHED FLOOR HIGH POINT INVERT LOW POINT RIGHT-OF-WAY x EXISTING CONCREfIE PAD (4994.5) EXISTING EXISTING CONCRETE PAD � (4995.4) CONCREfE WALK (4994.9) �. a`�.� m�n- . �::: , ��' �7 �— _s ��,��E � � — � � , � �s —_i L j� �.. LrL�,.J I 9�� J �� I'(�� r—�. N��— L � �_ , � _ � � - r , (4995.6) — — — — — = — -.� � � �� ( ' (�jq� � ,�.��,� XISTING GRAVEL � , EXISTING CONCREfE DRIVEWAY TRACKS -�� _ � < - � _i ' �� 4994.6) I I �� PARKING EXISTING EXISTING HOUSE �29 � (4994.3) LANDSCAPE� � � � LP PAVERS � � m ��. (4994.5) N (4994.9) i � I (4994.4) g �P - \ �__ �, �,� o., 9� �� — a� � _ __ OA7 .�: � s\ _ �� AC \ _J � 9p. J \\ 29� .��'9 _ ;__ _ i- —�—� � � � 6 . �-- ' �r_ � � � .�,i_v,- ' �. _ _ i.— � 0 _ L..:'.,— �� \ \ (49�94.9) — (4995.0) _. ., i;z ;_i LEGEND: '_g9�91 �� x (�%) r ~- � — _ — DS _ � � — — �� F.,oNn x. 20 0' 10 20 40 `- t.-_�— �.—� EXISi1NG CONTOUR � �� = 2O� EXISTiNG SPOT ELEVATION EXIS7ING SLOPE EX�STiNG CONCREiE TO BE REMOVED EXISTING DOWNSPOUT AND FLOW �IRECTION . �c,9�01 II� ! `� � ��' I; f��.yal � rI ,J.9Ik0� �� .�� '�� . �<� �� I;.:� ��I�� kg9� A1 I�, .I I \ I'I �� I IP' ��II ,O�'.�pS�•L�•!r •�SC . C? F �• : �� mi i 39378 e �•�' :�4 �,�. •. �/ONAL E� W W � � N 0 � 3 � W _ N H � � Z J J � 0 UNomw Y��rn� , '�� 1� 1� `1 `V � � W � lJJ m � _ N X o � W � Q W O J � Z U LIJ Q Z J N � O = U � � � ¢ O 0 O Z N M = C'� N sH�r 1 OF 2 �i _ � _ _ � � � � �� ,�' Adjusted Adjusted Adjusted Adjusted Changein �I' �� i I HardscapeorHard Historic Historic Hisrori< Hisroric Developed Developed Developed Developed Impervious �/ �� / Surface Area A(sf) Area A(sf) Area B(sf) Area 6(sf) Area A(sf) Area A(sf) Area B(sf) Area B(sf) Area (sf) � --yV I Concrete 175 175 890 890 95 95 710 710 I` Rooftop 0 0 1,300 1,300 475 475 3,188 3,188 I�I�'� I I Pavers(40%) 0 0 108 108 0 0 0 0 I ' `'� Gravel park�ng (40%) 720 28S 0 0 0 0 0 0 -'� li y I TotallmperviousArea 895 463 2,298 2,298 570 570 3,898 3,898 1,707 I � N $ - W �o 1�� } ' � ,- � r� -- �r�.'�fiirr-� �� - �� ' � � �'\ � , � , . . ., - . , J�� D5995 �, �- --�� -� -- � �- ' I� � � . � 49 � Q , .b. .� . � .; . . . r � � � �,:_�:. A . �, -- � I� � r ., r • . � ps ,_ , �,. -�" -�-- -�_ ,--=� - �-�" � � - m = DS 9R . . , � ��- -� .- • -',�`. '�'�-- U w > �'� o.oaz .fi r � q_ � � � ' � ��m� � r= AC �O r:. � � , .��.i �� l�i°�'�Os —v o W �� 1 I PROPOSED GARAGE � � f� f� PROPOSED A�DI110N � � I ; I I I = W� o o� _ N _ � r ' �' . - - -, � B —I� . EXIS7IN� HOUSE - - � � y Y � o � � I�— _ � , _ ; - . � DS I I � I -f' � r F' ' S i �� -- r 0.192 " � � : I Q � AC ��__ I O I Z �% , . , , � / , _ � --► � ` � '; ... —. l .- -- �S'r ll `'� i ' 1 • .-- . _ , _ � ��, � � DSI �. . _. .. _ .... DS � �� - - �� - � �—� i 1I � �•-� - _ - - - , 1 �„�� _ --- — . � �� . � . , _ — _ � `, � — � , _ � I� _ �� - � r:,:� W ~ LEGEND: � _ -?5��94 EXISTING CONTOUR 20 O� 10 20 40 �� 4994 PROPOSED CONTOUR `--��--�—��—� O� O J ABBREVIATION LEGEND: PROPOSED CONCRETE �� = 2O' ��Q,PDO LICF2s o Z U DS DOWNSPOUT � ��••N L�•kF�' �� a fA G� P DWG �RAWING � �� t<`,�; EG EXISTING GROUND DS _ PROPOSED DOWNSPOUT AND FLOW DIRECitON '� m� W Q J EX EXISTING � 39378 C = J FF FINISHED FLOOR ` ; (A FG FINISHED GRADE �'' PROPOSED FLOWLINE �'. : Q �� FL FLOWLINE �p� �,� ,� k,�' = W � GB 6R DEEBREAKFACE (CONCREiE) � CONCENTRATED DRAINAGE FLOW DIREC110N FSS�ONA�'�NCa�� d� � 0 GFF GARAGE FINISHEO FLOOR ��•i OVERLAND DRAINAGE FLOW DIRECTION Z W LL HP HIGH POINT INV INVERT LP LOW POINT � � � �RAINAGE BASIN BOUNDARY LINE > ROW RIGHT-OF-WAY FOR DRAINAGE REVIEW ONLY N Q DRAINAGE BASIN ID NOT FOR CONSTRUCTION � o.oas , �� Knowwhat56BIOW. 2 OF 2 DRAINAGE BASIN AREA (ACRES) C811hetoreyoudig. � Hydrologic Soil Group—Larimer County Area, Colorado � � (233 North Sherwood Street) � 0 0 432785 492793 492@71 492803 492817 492825 492833 492841 492849 492857 492ECv 40° 35 26" N I *I I I # I � I T� 40° 35' 26" N ��_ :� � � �- � ' � - . - `� ''� � r I � � �� - � � . , � F � �� ♦ �4 r � � . � �. �r � � � � - , . � �. , �� ,� �,�t;�' � •w � � � ,,�„ � ` �, - •,�' -'� _ _- - � � �� , T = �. � —�+„�� .s. „ � '� � � �- ,_ � - - �' ��_ - �y � �� * -�_� +�� . �� I�- � t ��--_- � � � � � ��- - � �. . � ; .,.:...,�,��'�_�'�- ' - - - , �� , _ , � , . i � _ � _ .� � . �.. � � --- =. � . i - . � i� � i - __ � ,�,� �_ ' � � ` � ; � � � � _....� . _ . , � � � — � , � � ,�"1 • • ` � —•--- � _ " _ ' �. i � . , . ,M_ � � � � + � ' � • ~ _ � . � �—+ So`i'I Ms�p may not t�e valiel �t tliis sc�le. ` —� �� . 40° 3S 24° N � i"�'� . y' I,� . _ I �" 40° 35' 24" N 492785 492793 452�1 432@�9 4�817 4�5 492833 492841 492949 4�857 492� 3 3 io = �^ Map Scale; 1:371 iFprinted on A la�dscape (il" x 8.5") sheet. � o N Meters � 0 5 10 ZO 30 /V � 0 15 30 60 90 Map projectlon: Web Mercator Cc�mer coorcJinat�: WGS84 Edge tics: UTM Zone 13N WGS84 USbn Natural Resources Web Soil Survey 2/6l2020 � Conservation Service National Cooperative Soil Suroey Page 1 of 4 Hydrologic Soil Group—Larimer County Area, Colorado (233 North Sherwood Street) MAPLEGEND Area of Interest (A01) Area of Interest (AOI) Soils Soil Rating Polygons � A Q A/D 0 B � B/D Q C 0 C/D � D 0 Not rated or not availabie Soil Rating Lines . � A o � � C/D � D � Not rated or not availabie Water Features Streams and Canais Transportation � Rails �..i Interstate Highways US Routes Major Roads Local Roads Background � Aeriai Photography .�.i A/D ..� B �r B/D . . C . r C/D .�.♦ D .. Not rated or not availabie Soil Rating Points o A 0 A/D ■ B � B/D MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 14, Sep 13, 2019 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. USbn Natural Resources Web Soil Survey 2/6l2020 � Conservation Service National Cooperative Soil Suroey Page 2 of 4 Hydrologic Soil Group—Larimer County Area, Colorado Hydrologic Soil Group Map unit symbol 81 Map unit name Paoli fine sandy loam, 0 A to 1 percent slopes Totals for Area of Interest Description Rating 233 North Sherwood Street Acres in AOI Percent of AOI 0.3 100.0% 0.3 100.0% Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff.� None Specified USDn Natural Resources Web Soil Survey 2/6/2020 � Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Larimer County Area, Colorado Tie-break Rule: Higher 233 North Sherwood Street USbn Natural Resources Web Soil Survey 2/6/2020 � Conservation Service National Cooperative Soil Survey Page 4 of 4 National Flood Hazard Layer FIRMette 40°35'38.82"N N '�"��`� — ''V — �y� - � o �� h. i � � , � r �i f � • �. � '� � � ,�� + . r • '' ►�'� �+ � ' � J ► -�� ' 1. . �_ FEMA Legend SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT Without Base Flood Elevation (BFE) zone a. v. ass SPECIAL FLOOD W�th BFE or Depth zooe ae. ao. aH. ve. aR HAZARD AREAS Regulatory Floodway �� •�. `e' � j � �� / , _ .� '• ��-,� 'V ' _ � � t I : I�, ' •I ' l �� * �F'` 1 ' � � 4 � .'� • ? . �.;.,h' �'� . • �`� �i . 1 t f ~ � �� a f 1 � I r � t `�' • r � ` '"'�� `, • , I�I � � � ,� � •�,' . 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I �1�6�'� � ,� •� � � ?, � � _ 1 u �: w -� � _ + 1 , �� . . � r�r � � s t �' Feet 1:6,000 0 250 500 1,000 1,500 2,000 ��. 1 . ..,,,�, *_ � j_ ��r;�a � `"-� � Vla :Orthoimagery.� OTHER AREAS OF FLOOD HAZARD e z°'Z Cross Sections with 1% Annual Chance ��•5 Water Surface Elevation 0- - - Coastal Transect ..... 5,�.,.._ Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary --- --- Coastal Transect Baseline OTHER _ — profile Baseline FEATURES � Hydrographic Feature NO SCREEN Area of Minimal Flood Hazard zo�,e x � Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard zo„� � GENERAL ---' Channel, Culvert, or Storm Sewer STRUCTURES i i i i i i i Levee, Dike, or Floodwall �� I � MAP PANELS . . Q � 1 �._'. . .��•�•�- . i '""�` � � a.�r�. �� - � o cn r . � A A A a,�aT��ciA�� 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile zo;,F x — � Future Conditions 1%Annual = Chance Flood Hazard zo�,E x Area with Reduced Flood Risk due to Levee. See Notes. zo�,e x Area with Flood Risk due to Levee zone o Digital Data Available � No Digital Data Available � Unmapped The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directiy from the authoritative NFHL web services provided by FEMA. This map was exported on 2/6/2020 at 8:1627 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the foilowing map elements do not appear: basemap imagery, flood zone Iabeis, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. �� 1 ��i a�� t�,� � �►� � . ` � � li� ��t_��ns FCMaps - 233 North Sherwood St ��.,� � sr�� Project Site � � � � ,. � , , ��,- I I 1: 857 � Notes , ,. �,, � � �� i Legend Parcels FEMA Floodplain ■ FEMA High Risk - Floodway FEMA High Risk - 100 Year FEMA Moderate Risk - 100 / 500 Y� FEMA Map Panel City Floodplains ■ City High Risk - Floodway City High Risk - 100 Year City Moderate Risk - 100 Year ❑ Growth Management Area Parks schools Natural Areas �_; City Limits 143.0 0 71.50 143.0 Feet This map is a user generated static output from the City of Fort Collins FCMaps WGS 1984 Web_Mercator_Auxiliary_Sphere Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. City of Fort Collins - GIS MAPLESTREE7 � � �Q--— � �I�-- �IIa--�--- � � � , � �, , n�; j I I �,I �, I - i �II � W e TOPOGRAPHIC SURVEY 233 NORTH SHERWOOD STREET FORT COLLINS, CO �� :., p MR cL ^uw, LEGEND N p r uN � w�' p°�� . �.��E __� a. oM1��W.nR, � woo F '�— T.,.> „«-��_ � ��a�� ,� �_ o Ma�� ,� �a .� ��,.o�P��.. �_ nMR � �_�A POV� m,,.- �tNn�as>ce � �. ., , 2 �,,,� .ti�_ a� � � Composite Runoff Coefficient Calculations 233 North Sherwood Street, Fort Collins, CO � ( c,.�.q- ) � _ � � — V, Where: C= Composite Runoff Coefficient C, = Runoff Coefficient for Specific Area (A��, dimensionless A, = Area of Surface with Runoff Coefficient of C„ acres or square feet n= Number of different surfaces to be considered A,= Total Area over which C is applicable, acres or square feet Equation 5-2 Historic Drainage Basin A Historic Drainage Basin B Developed Drainage Basin A Developed Drainage Basin B Minor (2- and Runoff Minor (2- and 10-yr) Major (100-yr) 10-yr) Major (100-yr) Minor (2- and 10-yr) Major (100-yr) Minor (2- and 30-yr) Major (300-yr) Surface Type Coefficientsl Area (sf) Composite CZ Composite C3 Area (sf) Composite CZ Composite C3 Area (sf) Composite CZ Composite C3 Area (sf) Composite CZ Composite C3 Hardscape or Hard Surface Concrete 0.95 175 890 95 710 Rooftop 095 0 1,300 475 3,188 Pavers 0.50 0 108 0 0 Gravel parking 0.50 720 0 0 0 Total Impervious Area 895 2,298 570 3,898 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope <2% 0.10 705 6,304 1,280 4,457 Total Drainage Basin A 1,600 037 0.47 8,602 032 0.40 1,550 036 0.45 8,355 0.50 0.62 Notes: 1. Runoff coefficients per Fort Collins Stormwater Criteria Manual Table 3.2-2. 2. Composite runoff coefficient per Fort Collins Stormwater Criteria Manual Equation 5-l. 3. Frequency adjustment factor per Fort Collins Stormwater Criteria Manual Table 3.2-3. Table 3.2-3. Frequency Adjustment Factors Storm Return Period Frequency Adjustment (years) Factor�Cr) 2, 5, 10 1.00 25 1.10 50 1.20 100 1.25 Table 3.2-2. Surface Type - Runoff Coefficients Surface Type Runoff Coefficients Hardscape or Hard Surface Asphalt, Concrete 0.95 Rooftop 0.95 Recycled Asphalt 0.80 Gravel 0.50 Pavers 0.50 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope < 2% 0.10 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.20 Lawns, Clayey Soil, Flat Slope < 2% 0.20 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 035 Sherwood drainage.xlsx Drainage Basin Runoff Calculations 233 North Sherwood Street, Fort Collins, CO Area Minor Major Initial/Overland Timel Travel Time� Final T� Intensit (in/hr 4 Basin Flow cfs)5 Basin Length Slope Minor to Major to Length Slope Channel Velocity tt Minor Tc Major Tc (acres) Composite C Composite C 2-yr 10-yr 100-yr 2-yr 10-yr 100-yr (ft) (%) (min) (min) (ft) (%) Type (fps) (min) (min) (min) Historic A 0.037 0.37 0.47 35 2 6.4 5.6 NA 6.4 5.6 2.63 4.49 9.63 0.04 0.06 0.16 B 0.197 0.32 0.40 150 1 17.8 16.0 NA 17.8 16.0 1.75 2.99 6.52 0.11 0.19 0.52 Developed grass A 0.042 0.36 0.45 5 2 2.5 2.1 40 1 1.5 0.4 5.0 5.0 2.85 4.87 9.95 0.04 0.07 0.19 swale B 0.192 0.50 0.62 40 1 7.1 5.7 160 1 grass 1.5 1.8 7.4 7.4 2.47 4.23 8.63 0.24 0.40 1.03 swale Notes 1. Per Fort Collins Stormwater Criteria Manual Section 3.3.2. i.s��i.i-cxcf�� T' 3� Where: C= Runoff Coefficient, dimensionless Cr = Frequency Adjustment Factor, dimensionless L= Length of Overland Flow, feet S = Slope, percent 3. Per Fort Collins Stormwater Criteria Manual Section 3.3.4. A minimum T� of 5 minutes is required. T�=to+tt 4. Per IDF Table for Rational Method, Table 3.4-1 Fort Collins Stormwater Criteria Manual. 5. Per Fort Collins Stormwater Criteria Manual Equation 5-1. Q = CIA Per Equation RO-4: Swale flow velocity, V= 15*S1�z Tt=L / 60*V Where: Q= Peak Rate of Runoff, cfs C = Runoff Coefficient, dimensionless I = Rainfall Intensity, in/hr A= Area of the Basin or Sub-basin, acres Sherwood drainage.xlsx