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Home My WebLink AboutGrading Plans - 08/09/2021--r.�6w—e - zR�-='9 \'""-�_-__-! _�_P�:-�N�� I 1 � �(� — 1 R� � ctovt'ac�Re I . Ib— (s�_es. RD elb .G� . � I � { � I � I o . sr e ( /�a/esl � ° �i i -i ��I p�o+ � O a >> � � y ' '� c� i � g'� I .o � f .��a �f'�'e .I I Z �� I � H �. . - oavz ay.rb. w wa . . ,1 .. g b /o Q �<aM1i PS k� � 4 e /If ; n I I i ee � i �` \� � \/ Y > E oU �- � '` - — . � �E,.�� ti � :�, 1 .� I�� Ro o� s ic a ...,., -_ .,,. �%I n'is*i � �o- � —! —" `x ` R I s� ( J� Po�a=�_ _� _ ��ioo __ � _ � �5a �'�� WOODLAND WAY ,n ..� -N-89'S6'L6"E..... .- I15.M'- ry.l $ 8 I � Ls a � o � — — ,� IW � U � y5 � W ❑ M e,,, :,. — r.o \ W I � W o 5 .� L-' ^ �-� — fi� -- -,� ��, ; e — _ 2Y�' W ] --�r 8 � �—`_, � �� I-8�urir.iry EAs[MENT ^ �.. e . 5P9'SG'Zj"�W IOO.ro' Li.l .II�I :•i40 N95.33YWCiZx F r WODDLAND/ y�/qy I EUI�DER-GIUc/qNoi FATHER ODE� N a . � R -85a I - DATE - 12/2Z/H9 1 �..-_ _ — _ _ 5'rewaPi€qssouArES V ;i] tl �, R.-,_. '_�`-(szil � �� +v Acxr or wnr �ONT CO;.�iINSUCo 8052ti CAM9CRCUiiI�Rc53BYCAGLe�GMAI�.COM o t�ouNon.oN mus* ee nr �u� e ne �. r-t r+= sr c � ouN�.mc nu eoiiomcs. z,�ERF ��=r a� A M��M�� RA�F oF 5, �wA �Ro r_� ��.��_ �,�� .�R< s o,o FE� �aA«N, ,o 3, ALL eLOPF.5GMU5? MELT TNC 41NIMUAI REQUIREMFNT OF 2% (UNLE55 SHOWN N:RE OTHFRWISE) ANp ARE NOi TO PE STEF.PCR T3AN 33R (3',1�). . E%IS'flrvC, �REES ip BE �'fECiEO �N VLACE. 5 BO � R -OC ,0 5 P RO AiE 0 O � 0 L . ., (. GATES 12/22/B �N ATON . . coN.Ho. s�n.� s.. vEari_oAer r+E�. coNi��c oH a rr.a��nNv .,on�s �ucnc^. oR oTM_a MaRo�mr� rs. �� rnardsurfare ., is�a ea�sFl IaaWzreaHisroncnrea�zf�oe.elao�sirenrealsf� `Qo`5'1iop onlzo�xl ' _ ' _ - _ _ - �elnovl f _ . _ _ � _- _ — _ -_ an7�:cea srte impery o�:ners II �,axs Groding/Stormwater PlanAccepted 19uilalnB Permitaeleasea� A�[epledby�. MattSimpson IJate� OS/09/2021 � �' t' � �—I 1" _ 'p' � � [xisrxc r+csr,rNCE I o �3e t Gk91 805 OTf M Of 5 �P PS Ol f]WG NA Ea 5 veva FR �No.i oMo FG H I]- GI' re*N HAJ FLOORCRElE) LP � 0 NT Ro �oor naa w flOw Flf,xf OF nv i0F i0P OF SOUNUAI'ON e5h X 33� �6 x �� ) � � RD y Zw UJ � W�o�W W��o�) Ym�� I� 1� 1� _`� � ON R�SU'N.�p CXIS NGAi�� B6].I� J E%IS�NC S�0! F1EVAlI01v PEk ORIGINAL a P�or � �s�wARr � � W A�� , ,6a;� PR�o=E� ��P_ � a o. f%ISPYC SI.OP: � Z Z Q FRp��SE� CONCF�Pc Q � � � E%IS�NG GRA1F fJ R-N.AIN O _y � KJ Pkoaos�-o �Fnvc� ��. � v'' Z PRCFosco r�owuxc � XOOF pRNN nN� FOW DiNEC1i0n� Q � � i�_�. � — ^�^�^� 1 OF 1 � Callmmieywei� ,, � ; , �� , __ � ---- _ � - -� � � %/ ,�,� -= i�iiiii�� August 6, 2021 Water Utilities Engineering City of Fort Collins 700 Wood Street Fort Collins, Colorado 80522 RE: 4528 Woodland Court Drainage Meino Parcel #9735331036 To Whom it May Concern: KEEFE CIVIL, 1NC 3125 Crockett Street Fort Collins, Colorado 80526 (970) 215-6808 meg@keefecivil.com Keefe Civil Proj ect Number: 2021-017 The purpose of this memo is to describe the proposed site iinprovements and potential drainage impacts at 4528 Woodland Court (Exhibit A). The 0.197-acre project site is a developed single- family residential lot with established landscaping located on the northeast corner of Woodland Court and Woodland Way in Fort Collins, Colorado. The lot is bound by existing single-family residential properties on the north and east lot lines, Woodland Court right-of-way to the west, and Woodland Way right-of-way to the south. Current conditions at the site include a single-story house with no basement, an attached two car garage with concrete driveway, a 12' x 20' garden shed, an 8' x 10' concrete patio in the back, gravel parking, established trees, and lawn area. Per the NRCS Soil Survey of Larimer County (Exhibit B), the site consists of Nunn clay loam and is classified as being within hydrologic soil group C. These soils are anticipated to have a slow infiltration rate when thoroughly wet and a slow rate of water transmission. The site is located within the Mail Creek drainage basin. Per the flood insurance rate map, the lot is located within Zone X. Zone X is defined as an area of ininiinal flood hazard and does not have a base flood elevation associated with it. Also, the site is outside of all Ciry of Fort Collins nlapped floodplains. (Exhibit C) Historically, site stormwater has drained with average slopes from the north to south in the backyard and from the east to west in the front yard, when not infiltrated into established landscaping. Proposed site iinproveinents include a 28' x 32' detached garage offset 4 ft east of the existing house, a 12' x 32' concrete apron, and additional gravel parking between the concrete apron and back of sidewalk along Woodland Way. The existing concrete patio in the backyard will be removed and replaced with steps between the existing sliding glass doors and the proposed concrete apron. The existing garden shed will be relocated east �11 ft. The lot's total adjusted iinpervious area will increase by 1,426 sf as indicated in the following calculations. The proposed impervious area for the site is �47%, which is consistent with low density residential land use criteria of 50% iinperviousness stated in Table 4.1-2. of the Fort Collins Stormwater Criteria Manual (2018). : .7 i .� .> ;:a :.s :� .j .:. .3 � :� .} .� ►� � G' O 9 T� G Q t� '� � O 0 B 4� a d e � d a a a a a a a a d a d d d d d d d d d d � Q Q G 4 a v G G a a G Q v a a a Q Q a a G Ei G Q q C > ev av, Q� `�Q �� 4r., d'v �� 4r.� �e;. �� cv �v ao �t� �t. dv �o �c� �v �rl �r� �� c �r� ' AA4A�AG�AAG��A.AAA�s�'AG�4t�.AG�A'A� 4528 Woodland Court Drainage Memo Pa�e 2 of 2 Keefe Civil Project No.: 2021-017 August 6, 2021 Historic Adjusted Developed Adjusted Lot Area Historic Lot Area Developed Area Hardsca e or Hard Surface (sf� Area (sf) (sf� (s� Concrete 510 510 930 930 Rooftop (90%) 1,645 1,481 2,540 2,286 Gravel Parking (40%) 1,645 658 2,145 858 Total Impervious Area 3,800 2,649 5,615 4,074 Adjusted Basin Imperviousness 1,426 sf Existing drainage patterns will be maintained with proposed improvements. A lot line swale is proposed north of the garage and is intended to provide the required drainage away from the garage and house foundations and out towards Woodland Court to the west. A drainage swale and drainage pipe are proposed between the house and garage to provide surface stormwater drainage south into Woodland Way. The proposed garage roof drains shall be directed east, into a pervious area with landscaping to allow for project stormwater infiltration and increased water quality with site runof£ ' ' , , Permit[ed under consis[ent wi[h criteria manual imperviousness for low ' density residential land use. - Matt Simoson The composite runoff coefficient and drainage basin runoff calcu ations or t e istoric an developed site are included in the enclosed tables (Exhibit D). Using the Fort Collins Stormwater Griteria Manual (2018), the proposed stormwater runoff will increase from historic rates, as indicated in the summary table below. 2-year 10-year 100-year Basin A Historic Runoff 0.25 cfs 0.43 cfs 1.16 cfs Basin A Develo ed Runoff 0.33 cfs 0.57 cfs 1.46 cfs Based on the enclosed design, it is my professional opinion the additional runoff generated by these site improvements will not cause adverse impacts to downstream private properties. I hereby attest that this letter for the final drainage design for 4528 Woodland Court 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 assuine liability for drainage facilities designed by others. Thank you for the opportunity to submit this drainage memo. Please do not hesitate to reach out to me if you have any questions or coinments regarding the above items. Best regards, Megan L. Keefe, PE / Manager Keefe Civil, Inc. ��p,DO LICF� o�, .••••� •••. s C> ; �PN ' /<<c• ;FO :�� m: i 39378 : . . . . -o• •� 9� �� o�FSS��NAL EN�\�� Enclosures Cc: Gary Cagle, Property Owner .��.?�.��, 4 �,3 -3 -3 -�: 3 -� -3 3 -3 -� -3 � 3 -� � -�: r% v v' ��r% v v�i v v Q r% Q a v� 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 > °v °� °o °c °� °� °c °v °c °c °a �� °o °d °a °v °c d °c °Q °o °c °c °o °c ' AAAG��AAAt�s�AG�G�AL�CsL�.AA�A.4,C�►�'A6 � . .� � --r— -- —� � f -� I � ,_ .,� << � , —�- �� , RO // . uRe I F� �_ [� ( - R� � � ` µi� .In� ;�� "iy _ � � ; ♦ � � \ � �I Ix M�vcFF-�s; I vi. � J aat ie 5 �� '. �i' � � � O � I �4 I O lo. � � � �� , .,- � J Jr ,. n._ \..�i� �' -`6 �o'f A• I nl � '� ie � � I ' �- U ` . � S �- � � �I � , �r r�, ' � R➢�P —�a�o O�� '�°o � — �.— — — — '.�7 � µ� 1 .r�,�. oCL_"__ ' e_ i,. _ >:. .. —. .. ,os ce�zs�w _—�__ .. . . � . � ._ . � �_ i � ��.e — � uve •v 1 �vn� WOODLAND WAY , TI _N�89°SG'LL".E.. - — 115.00'� (y.) �8 I �— cs.� F o \ � F 8 o �9 — — \o. I� � �su ° � ��1 v.o � W W g L 3 n � - fis ] - $ -- —�%�' " g � n �� _, �—�� I8�Ui1LnY EASEMENT j� .v B 58'SG'Z6'W IOo.00' 4E�� ili . �p�pp00' ARC 56' � N95°o1=t'Wi., ..R-I�M' �� WOOD.AND y�/qy _ I III� .FUI�EER-GIUCIqNOiFATNER R-B50 DATEL Ni2/2z/89 _ SiEWARTEq55p�qiES A, �� R� �_.��, _oM 0 CU4D U 'S �r 5 � JY i C ' E DC 0 NC L 8 UI�iG P � i FE ' U f DE 0. �4� FR i E�, . LL Nf f I 1',." Sf . 0 � F E C, � E �0 L C I N M �CET -�F E IUU�I '3_Ul FLNtN CV 2 0',V�LE S 5 �Wry FE3E � E w�l.) MIG AFE NO f0 CiE �{Lt tlE ' ' ! LL L4'E. 3 � R rE f/._.Lt Lft.�� .�0 tlF .i..a oiP V�V�t�_A�J rnardsurfare ., is�a ea�sFl IaaWzreaHisroncnrea�zf�oe.elao�sirenrealsf� `Qo`5'1iop onlzo�xl ' _ ' _ — _ _ — �elnovl f _ . _ _ � _— _ — _ -_ an7�:cea srte impery o�:ners II �,axs io 0 0 � Fa s D G 4 ; � f r� . r vr .xo.�rc �ry cw�� _ (J ^��J= B b I !` LV�F �Ip C. ]� J �5 �. 'IOn 5� %� S �=-y (�R� I � I � I RD y EYtSl:l Z W N o JpO ��o`�U Y'n�m� , 'j ; � 1� I� \ � � \ oNti�_��„,,N��_s,� � t � (��EwnR� a � Il� �< <�F � a E%SP Or Q ' Z Z Q �, o g � Ex_n ��,E_ � k�� °o � � � r,aorosEo can�,e_ � � N, Z�' �2UiO5E� ROWLl1E Q o„o� oun�u r.no F�.nm o�c�ccinN � V �� i�: b�^� 1 OF 1 x� calle�aew�ag. � 0 � 0 aszasa 40° 31' 28" N � :3 � � � EI asza� �� .� � I � ~<_ � Q4 - _�� Soil Ma�� rnay not tie valid at this' scaie. �� •�,► 40° 31' 2T� N ,.�- .' I,, I 432464 4924� 492474 492479 492484 4�JL489 3 b N Map Scale: 1:236 if printed on A la�dscape (il" x 8.5") sheet. � N Meters 0 3 6 12 18 /V � 0 10 ZO 40 60 Map projectlon: Web Mercator Cc�mer coorcJinat�: WGS84 Edge tics: UTM Zone 13N WGS84 Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Suroey Hydrologic Soil Group—Larimer County Area, Colorado � (4528 Woodland Court) `� � 0 as2a�a as2a� aszaea aszac�a aszasa a9za� aezeoa a�zsa� aez5�a - �� . � � ,�. � � � 40° 31' 28" N _ � � . � ��,� '�'� * �G _. �__ ^ � '�"" � _ . � ` I J � _ � � .�'''� ,' '�. _ z a r ,� .� p p� I;_.� _ � u � �� - � � . � � � r E9 � � � 40° 31' 2T' N 492514 3 � 4/9/2021 Page 1 of 4 4924&l 4�J2499 492504 4J25L� Hydrologic Soil Group—Larimer County Area, Colorado (4528 Woodland Court) 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 r � A � C 0 C/D � D � Not rated or not availabie Water Features Streams and Canais Transportation � Rails �..� Interstate Highways US Routes Major Roads Local Roads Background � Aeriai Photography • r A/D . r B • r B/D • r C � r C/D � � D .,� Not rated or not availabie Soil Rating Points o A � A�� O B o g�o 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 15, Jun 9, 2020 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. Natural Resources Web Soil Survey 4/9/2021 Conservation Service National Cooperative Soil Suroey Page 2 of 4 Hydrologic Soil Group—Larimer County Area, Colorado Hydrologic Soil Group Map unit symbol 74 Map unit name Rating Acres in AOI 0.0 0.3 0.3 4528 Woodland Court Percent of AOI 2.6% 97.4% 100.0% Nunn clay loam, 1 to 3 C percent slopes 75 Nunn clay loam, 3 to 5 C percent slopes Totals for Area of Interest Description 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, soi�s 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 Natural Resources Web Soil Survey 4/9/2021 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group—Larimer County Area, Colorado Aggregation is the process by which a set of component attribute values is reduced to a single value that represents the map unit as a whole. A map unit is typically composed of one or more "components". A component is either some type of soil or some nonsoil entity, e.g., rock outcrop. For the attribute being aggregated, the first step of the aggregation process is to derive one attribute value for each of a map unit's components. From this set of component attributes, the next step of the aggregation process derives a single value that represents the map unit as a whole. Once a single value for each map unit is derived, a thematic map for soil map units can be rendered. Aggregation must be done because, on any soil map, map units are delineated but components are not. For each of a map unit's components, a corresponding percent composition is recorded. A percent composition of 60 indicates that the corresponding component typically makes up approximately 60% of the map unit. Percent composition is a critical factor in some, but not all, aggregation methods. The aggregation method "Dominant Condition" first groups like attribute values for the components in a map unit. For each group, percent composition is set to the sum of the percent composition of all components participating in that group. These groups now represent "conditions" rather than components. The attribute value associated with the group with the highest cumulative percent composition is returned. If more than one group shares the highest cumulative percent composition, the corresponding "tie-break" rule determines which value should be returned. The "tie-break" rule indicates whether the lower or higher group value should be returned in the case of a percent composition tie. The result returned by this aggregation method represents the dominant condition throughout the map unit only when no tie has occurred. Componenf Percent Cutoff.� None Specified Components whose percent composition is below the cutoff value will not be considered. If no cutoff value is specified, all components in the database will be considered. The data for some contrasting soils of minor extent may not be in the database, and therefore are not considered. Tie-break Rule: Higher The tie-break rule indicates which value should be selected from a set of multiple candidate values, or which value should be selected in the event of a percent composition tie. 4528 Woodland Court Natural Resources Web Soil Survey 4/9/2021 Conservation Service National Cooperative Soil Survey Page 4 of 4 � � C"ni��W�z�.-�f'=, �.��, �i Mail Creek � � ;�; � :� � � � � � � � Master Plan ' + ; ''; � �;= , � Water Quality Conceptual Plan p : ° �,r � r�'�' '` '�-''' �, � ii ��, ,.e, � . . �{ � � y• . �' yr , ... I T ( n Pontl "� "1 +. ' . . . � . .. I R f M1[ExlstingPontl� w* ��"�� ' -.. . . . . - . . '� moaareWater4 rryC . M . , � . . ' � ' ' Volume � .y, . . ` � . � .. —��.�.� 4,' . ,. . . ,ii .�. _ V in �. � Wootlntlae Pontl I � . • . . ' \ � � � � � I Lark�b gh P tl -...� : .. . RefroA[Exrsbn Pontl fo � � � � � � V/—Fi t E � g Pontl to � �� i�� modareWaferQualfry ' � ' acc otlateWa[ r0ualiry I��],'- Volum¢ - � � � Volume : -.`fiy� Z } �� I �� ,� . � � � � ,�;.�.� � � �.� 4 - ��,�� x�- �� ,�..� � �.� -f� � � � � �°��" ,, -,. �� t` ' . _ . .. - _ . . � � � E� � �'�. \ � P A � � fid�, - . . � .f'�'� e -_ � ,�� /� Ha,re ' N�'. d in �] � � i»k�� k 9 ' \ � ' � 7.j�4'i� R �'. � t � ( t� ��;� ��s4..� > � �s} '�" .. � � . .. � J:�� ,II�IIII . I 4Lc�F}'��' ) I .. � ' . �� J � "' J ', � .i. .. �...I Res . ... , i, ^; - ? �. ,.: . �� , �� /„� �` .... . . . t �� s � I:'.. '�..�^ / . � ;. � rn- ,;. + ( � � Mail Creek Basin Boundary '. � _ �, � m�� "� Proposed BMP Basin Type 5Y � —�" L � . � ,� A ° � . � \ � � . Flood Conlrol Only � � . ♦ Water Quality Only - � � � rropo:ees�ream . - Flood Control and WaterQualit � aesro.anon � . - �._ Y � -: . '� �� ImP/ovement ..-------- -�FirwaYPontl � � � - -- � � Revo��ren:a�yPondro � Proposedimprovements . . _ �. �' ; �. -:� _. :, � . _ `. ..�,'' . � _ � v � a��om,,,ona�e w �e.ouany , � .,� ; . � � -- .. _.. vomme . None . � . � , _ � � -� �. . � � . . ; . � : ��,/ � -�, Proposed Conceptual , a � �/ � � � -° ed� Water Quality Aiternatives � -; -� ,�ii, j,�:. � - � � � �. � � /� Proposed Water Quality Pond . <> � , � � � ��-l�u'�rnl3-'-�nr7 � � �{'� UndevelopedArea . � � � � - � Water < . � � � -�.---Stream-Canal . . . . � � . � � _ � C] Parks _ � , . . � � � �� ,��.. Naturai Area ` � ' �, � . � � Proposed Stream Restoration ' - � , � � � :. y� ;�a:; . � � � and Habitat Improvements /�,�5 i , . , . �.. .. � . � . . ° G ree� � ASSOCIATES � � � � � M . National Flood Hazard Layer FI RMette � FEMA Legend 105°5'38"W 40°31'42"N SEE FIS REPORT FOR DEfAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS OTHER AREAS OF FLOOD HAZARD Without Base Flood Elevation (BFE) Zone A. V. A99 With BPE or Depth zo�,e ne. no, aH. ve. aR Regulatory Floodway 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„e x �. — � Future Conditions 1%Annual _-- Chance Flood Hazard zo�,� x Area with Reduced Flood Risk due to Levee. See Notes. zo�,e x Area with Flood Risk due to Leveezone o NO SCREEN Area of Minimal Flood Hazard zo„e x � Effective LOMRs OTHER AREAS Area of Undetermined Flood Hazard zo„e o GENERAL '--' Channel, Culvert, or Storm Sewer STRUCTURES � i i t i i t Levee, Dike, or Floodwall � Cross Sections with 1% Annual Chance ��.s Water Surface Elevation e — — — Coastal Transect �t+3� Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary --- --- Coastal Transect Baseline OTHER _ — profile Baseline FEATURES Hydrographic Feature Digital Data Available � No Digital Data Available � MAP PANELS Unmapped eThe 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 directly from the authoritative NFHL web services provided by FEMA. This map was exported on 4/9/2021 at 4:21 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 following map elements do not appear: basemap imagery, flood zone labels, 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. � �c� �.b�VUU 0 250 500 1,000 1,500 2,000 Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 �t��ns 4528 Woodland Ct � � � � , .r ! ,•�, _--�_ / I� ' — I � — �i I �I � ,. �,, , � � �� i P � � - � —^�,_ _.. , � � ._� 1� ;. � I I 1: 857 � Notes 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 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 Composite Runoff Coefficient Calculations 4528 Woodland Court, Fort Collins, CO �(c,��:A; ) c.= ;_� A, 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 Developed Dreinage Basin A Runoff Minor (2- and 10-yr) Major (100-yr� Minor (2- and 10-yr) Major (1D0-yr) Surface Type Coefficients' Area (sf) Composite CZ Composite C3 Area (sf) Composite CZ Composite C3 Hardscape or Hard Surface Concrete 0.95 510 930 Rooftop 0.95 1,645 2,540 Gravel Parking 0.50 1,645 2,145 Totallmpervious Area 3,800 5,615 Landscape or Pervious Surface Lawns, Clayey Soil, Flat Slope < 2% 0.25 4,777 2,962 Total 8,577 0.47 0.59 8,577 0.60 0.74 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 5-1. 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%a 0.15 Lawns, Sandy Soil, Steep Slope >7°/a 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°/a 0.35 4528 Woodland Ct - drainage.xlsx Drainage Basin Runoff Calculations 4528 Woodland Court, Fort Collins, CO Area Minor Major Initial/Overland Timel Travel TimeZ 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 ft o � ( ) ( ) ( � �o' yP ( p � ( ) ( � ( � 2-yr 10-yr 100-yr 2-yr 10-yr 100-yr () (/ min min ft / T e f s min min min Historic A 0.197 0.47 0.59 70 5 5.7 4.6 NA 5.7 5.0 2.72 4.65 9.95 0.25 0.43 1.16 Developed A 0.197 0.60 0.74 80 5 4.9 3.5 NA 5.0 5.0 2.85 4.87 9.95 0.33 0.57 1.46 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 2. Per Fort Collins Stormwater Criteria Manual Section 3.3.3. V _ 1.49 R2/3S1/Z n Where: V = Velocity, feet/second n = Roughness Coefficient, dimensionless R= Hydraulic Radius, feet (Hydraulic Radius = area / wetted perimeter, feet) S = Longitudinal Slope, feet/feet And: L T� - vXvo 3. Per Fort Collins Stormwater Criteria Manual Section 3.3.4. A minimum T� of 5 minutes is required. T�-iso+10 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 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 4528 Woodland Ct - drainage.xlsx