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Home My WebLink AboutGrading Plans - 01/08/2024 (2), � �� = � �_ �-'� r �. � � ; � \� - _ _ �'' _ - � �''� `� � � � j _% �� , � • .i,�L��' ��o� � January 2, 2024 Water Utilities Engineering City of Fort Collins 700 Wood Street Fort Collins, Colorado 80522 RE: 415 East Laurel Street Drainage Memo Parce19713216009 To Whom it May Concern: City of Fort Collins Approved Plans Approved by: Wes Lamaque Date: 1/8/2024 KEEFE CIVIL, INC 3125 Crockett Street Fort Collins, Colorado 80526 �9�0, 215_6g�g meg@keefecivil.com Keefe Civil Project Number: 2023-024 The purpose of this letter is to describe the proposed site improvements and potential drainage inlpacts at 415 East Laurel Street (Exhibit A). The 0.21-acre project site is a developed single-family residential lot with established landscaping located on the south side of Laurel Street between Peterson Street and Whedbee Street in Fort Collins, Colorado (Figure 1). The site is located within the Old Town drainage basin. ` � � -�� . �r - �� f . �� - :.- — �� , -� �-. ,; � _ _ �r� � `" . "q � - � , .i''�";. ` �� ; " +,- �� ,E,� '� ,. �.�..�- � .� � � � rr r _e.� ' �¢,�� .�: I � 4. ,, ,� .,, y �:,� _. '��• ''�:_ ,�- _ ' i3 ''' ...� �,�i.ry, ,z' _ "3� �° '�'_•'�� '�'^`A,�• - - - �-. .. T�.-t h- . ri-�ww . � � � � . �. �:.�:�; t � .�--� � �• r i..i�s.•��'.�',yra� . � . ,�- _ ,� � C � � ''"' �' . -.� ` t �� `� 1 f f� _ -'�. ", � :� R =��, -_1 �.`f a}��.. _.� + i �� i � t ' � el�. ti- ,� � . J .. _. <�� y - ,�'-` ; .�� _ •y � Y e ��... �"�:� �r'�,' �� , �� ; r�` "�� -� `a� _ ��z ��1 - �� ._ �'VJ �/� �' "Ld � �. r� �y � 3 ��y". _. 9 � �� . �� ,`(� � i � 'F'� •� . � y � � �,�� a� �� .� �r . . ��. k � � � '� '' �-�� . `t�,� � - ��'°-, _.^ M��' ..� �Y. . - �:� `{� .<� I� � � �' �..1 �'fi �� .. 3 F � y..�c•�y � ..3c�� .� .. . ` i i �r x� 'i? , t''�i`. k a �ta�__. '..$" � --'��' � �F = � .K. -a��-�-, , d. � . ' - „ �� ;� '.=- ; p�+ � Y.�' v 2 r�•' �. ♦� � �5 �' �4."'_ i e,��r�- '�` . � y-�� , . � V�'.� ��:. . �' `��,�' t°` i� � -� � :�`� -� f` � Figure 1: Vicintty Map - � �- . _-y -� - - � �-:i =�r i=�::t ��v =a� -=�i ��..s � � T7� 7� O� �� CJ� rd� O` 4� 94 O� T�� a� ti'� '�� ? tT� Qa IIa �� G� Q� T�3 DR � IIy , � a e e e d d d d d d d a d d d d d d d d a a d a C G C� G � G G G Q G Q a v G�0 q Q Q G a a G Q G G G G �� G' �� E7 fl4 pC �d �b aD ab dtr pD �b d!7 d�b �D QD �G nt7 C Q Qb dC �C � 4C�AA�AG3A'AAA.AAAG3 �►�AA��A�A�G�AG 415 East Laurel Street Drainage Memo Keefe Civil Project No.: 2023-024 Page 2 of 4 January 2, 2024 The lot is bound by existing single-family residential properties on the east and west lot lines, Laurel Street right-of-way to the north, and a concrete alley way to the south. Per the NRCS Soil Survey of Larimer County (E�ibit B), the site entirely consists of Fort Collins 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. Per the flood insurance rate map, 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. Also, the site is outside of City of Fort Collins mapped floodplains. (E�ibit C) Historically, site stormwater in the backyard has drained with gentle slopes from the north to the south, into the alley right-of-way. Based on field inspections, the alley drains east towards Whedbee Street right-of-way. The proposed site improvements include a new garage with a covered patio on the north and a concrete driveway apron to the south. The site's grading plan will not alter historic drainage patterns; however, more than 350 square feet (s� of new impervious area will be directed towards the alley. Where possible, impervious areas and downspouts shall be routed into pervious areas with landscaping to allow for project stormwater infiltration and increased water quality with site runoff. Since the lot's total adjusted impervious area increase is below 5,000 square feet (s�, water quantity detention requirements are not required for this development. Ad j usted Ad j usted Overall Site Hardscape or Hard Historic Site Historic Developed Developed Surface Area (s� Area (sf� Site Area (sfj Area (sf� Concrete (100%) 1,082 1,082 1,234 1,234 Roofto (100%) 2,375 2,375 3,179 3,179 Patio (40%) 215 86 215 86 Total Iinpervious Area 3,672 3,543 4,628 4,499 Ad'usted Site Im erviousness 956 Based on visual inspections of the alley during a recent rainstorm (Figure 2 and Figure 3), stormwater in the alley drains east until the end of the concrete improvements and then redirects southeast, onto private property at 717 Whedbee Street (Figure 4). Based on conversations with the Ciry of Fort Collins Street Department, the City has agreed to grade the dirt alley to ensure the stormwater will flow away from private property and into Whedbee Street right-of-way to the east. s-� ►3-p-�-� 1�-� -C►`�. �p-�. �-v-�-L3-p-� 3-� �-G�-�-p p-� D 0 Q Q�% �'% �% Ti Q C� D�J D�J D�'% V Q G'7 � T1 U' �7 T'i ' 0 a d a d d d d a d d e d d d d d d d e d d d d d � a a Q Gi G Q G G a a G Q v a O,0 a a G G G Q a a Q G > °d �c °� °� �'o �� °d °o °� �'Q °�, °o °a �a °a °o °Q ad �'a °� °a °D °�, °d °o � A�s=�.AQ�AAAAAG�.AAG3s�AAAAs�.4Ai�A'6 415 East Laurel Street Drainage Memo Page 3 of 4 �, � � �f —__ ��i _ i ,^. - � �� .- �,. �- > ��,�.� .�.,,,.,.� - - � '' =��.� ~" ,.�,"` �` • _ : �x „Z�' �;,.�' � s- ,.. � t � � 1" x� 4` � � _ ; r „y�k,� ¢�,,� c _ ; d..g 3.:� t ��;_ . . . `c � ` �� * 4 - . 4 ; �� N � ��.�rA' ' -L � �T4 'i�,� �� N '� Ft :4� � �i�ri L . rq.9fi��F � ( _ . v� ' „ �+�, �l, : � � �.•� - , .'Ay Q ��1' t.w 4 �{�'.�^" +�' . ✓ � _ O Y i� -, x h.;IF'� f . _ . i'. _ -�: & � J s� �, � s �� . �� 0.�� f - . � •� - • a;� � ,� y �y , ' yrL�r. �x,:�.� - .... . . _ . . �'3. .' r> _ � .. i. . .. .i.._ :..:n.'� � i. _ }y Figure 2: Looking wesl along alley fi�orn 717 Whedbee Slreel � .i C -- \,� � � � , � � - - ` ' �-; ��.,`�r ; �, -__.. _ �. . =c - - r.�:� + -�- � - ' `"��'� _ =s� ��`�_ "�s� -_- �. _ - ��. .�y�r'--, . ,,,."�' - �--a'�- . �_ -_: _ - _ . '�. - �. � � �- ' . ' : ` ' �.- . < . . - w ,�� ' ', � •.;�_'�� ' - - � ' - E__�� • -�'�n�. _ - . � _ �. rt_= n'� ^� � :• z ' . . . • �� s � • ': : � � ! + T � ••' ~ �K 1 t ' • -' ^ F` � ��`�„��_-_ v � �#�•,� • ��'-� _` ;:�z:� "'r- � ` �._ _ _ - y - : . Figure 3: Looking southeast towards 717 Whedbee Street Keefe Civil Project No.: 2023-024 January 2, 2024 � � s a0��'►,�.�`�4-"�`.�p---..�p--�+p-�.�.�vvG'`r��.''�-.��``"n-�a�a�'�'��`:�a_"`p�''a"'D`rP�p-�� D 0 Q Q J G G Ti Q t� D�1 D J D G� V Q G'7 D T1 7�7 T'r ' 0 a d a d d d d a d d e d d d d d d d e d d d d d � a a Q Gi G Q G G a a G Q v a O,0 a a G G G Q a a Q G > °d �c °� °� �'o �� °d °o °� �'Q °�, °o °a �a °a °o °Q ad �'a °� °a °D °�, °d °o � A�s=�.AQ�AAAAAG�.AAG3s�AAAAs�.4Ai�A'6 � _ 415 East Laurel Street Drainage Memo Page 4 of 4 ►�• .: �.� C� �', .• 1 ` . .A �� ' �� • Figure =I ' (�. 7 � .�-� �,��:.�. i ��" . , ,. , �, � �.r : i ; . f!--F"'* ' < .. • ,' N • .,; � �,a .i�� K- �. ,, . , � ,-+` � 4;:,.ac4,� . . �. ♦<1 � , V 1� � �� f . Stormwater c�rair�age patterns 1 � /r �=,r;;.�-��.�, � - .�' :, ' , � 1�. �� ',,�. �. . � �:,�`��.•" �.� ��,� , ,� fi� _� ,—.ti� � . / j+ _�}a ; ,. . } � �j ;., ,' �'��y < � �a '_.� } . � . .i'..v� ,��? f • � �! 1 _• � ; .�, 1�` �� j. J r � .� �• �q�c` ' , ��..�' -`_�,`'�,U � ��,� `` .+', \ : �s�4� '�: - ` . ��_ �� .� �` ��r.��4 � � -. . r ' 2��+� •' . ,��•:`.' Z�, i�M � �} :�--' �+ ' . � �.+�* 1� , -•'� . "tac. � � � 5 R'' "1� ��- �� / A �-i�+~; 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 as soon as the alley improvements are completed by the City of Fort Collins Streets Department. I hereby attest that this letter for the final drainage design for 415 East Laurel 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 assuine liability for drainage facilities designed by others. Thank you for the opportuniry to submit this drainage memo. Please do not hesitate to reach out to ine if you have any questions or comments regarding the above items. Best regards, Megan L. Keefe, PE / Manager Keefe Civil, Inc. Enclosures c��o�P D 0 UCF�S ��.....�� O : '� N L' /f '•. FO . � c��. � ��'O 1 /02/2024 �, ; : 39378 's . . . . �- �' �'•. .��, o��ss��NA� EN�'� Cc: Dana and Catherine Hoag, Property Owners s-� ►3-p-�-� 1�-� -C►`�. �p-�. �-v-�-L3-p-� 3-� �-G�-�-p p-� D 0 Q Q�% �'% �% Ti Q C� D�J D�J D�'% V Q G'7 � T1 U' �7 T'i ' 0 a d a d d d d a d d e d d d d d d d e d d d d d � a a Q Gi G Q G G a a G Q v a O,0 a a G G G Q a a Q G > °d �c °� °� �'o �� °d °o °� �'Q °�, °o °a �a °a °o °Q ad �'a °� °a °D °�, °d °o � A�s=�.AQ�AAAAAG�.AAG3s�AAAAs�.4Ai�A'6 +t�� Keefe Civil Project No.: 2023-024 January 2, 2024 LEGEND: �9a� � X `�9g� 9i X 2% � ») ► � DS _ PROPOSED SPOT ELEVATION ca,S GAS LWE EXISTING SPOT ELEVATION �` � OVERHEAD UTILITY LWE PROPOSED SLOPE EXIST�NG SLOPE EXISTING/PROPOSED CONCRETE AS NOTED PROPOSED FLOWLWE PROPOSED RETAINING WALL PROPOSED DOWNSPOUT AND PLOW DIRECTION EXISTING FENCE E UNDERGROUND POWER LINE T UNDERGROUND TELEPHONE LWE ; ., FENCE LWE CONTROL POWT PINE TREE DECIDUOUS TREE SANITARY MANHOLE UNKNOWN MANHOLE ABBREVIATION LEGEND: __:�� FIBER OPTIC VAULT CONC CONCRETE DS OOWNSPOUT Adjusted De�eloped Adjusted DWG DRAWING OverellSiteHardscapeor Historic5ite HistoricArea SiteArea Develaped EG EXISTWG GROUND HardSurface Area�sf) (sfl (s� Area(sfl EOG EDGE OF GRAVEL � EX EXISTING Concrete�100%) 1,082 1,082 1,234 1,234 FF FINISNED FLOOR Rooftop�100%) 2,37"s 2,375 3,179 3,179 FG FINISHED GRADE aat a(aoi) zis ee � z15 as FL FL�WLINE TotailmperviousArca 3,672 3,543 I 4,628 4,499 FS FlNISHED SURFACE (CONCRETE) qdjusted5iteimperviousness 956 G8 GRAOE BREAK GFF GARAGE FINISHEO FLOOR HP HIGH POINT LP LOW POINT ROW RIGHT-OF-WAY IO O� 5 10 20 VERTICAL DATUM: NORTH AMERICAN VERTICAL DATUM 1988 (NAVDSS) & GEIOD78. ,� _.�Q GPS ACQUIRED ELEVATIONS USING TRIMBLE VRS NEfWORK. HORIZONTAL DATUM: COLORADO STATE PLANE COORDINATES NAD 83(2011) DATUM. (NAD83 COLORADO STATE PLANES, NORTH ZONE, US FOOT - CODE: C083-NF) HORIZONTAL CONTROL BASED UPON TRIMBLE VRS NOW NE(WORK. SURVEY NOTES: i. THE SIZE. TYPE AND �OCATION OF ALL KNOWN UNDERGROUND UTILITIES ARE APPROXIMATE WHEN SHOWN ON THESE DRAWINGS. IT SHALL BE THE RESPONSIBILITY OF THE CONTRACTOR TO VERIFY TNE EXISTENCE OF ALL UNDERGROUN� UTILITIES IN THE AREA OF THE WORK BEFORE COMMENCING NEW CONSTRUCTION. THE CONTRACTOR SHALL BE RESPONSIBLE FOR LOCATING ALL UNDERGROUND UTILITIES AND SHALL BE RESPONSIBLE FOR ALL UNKNOWN UNDERGROUND UTI�ITIES. 2. ALL PROJECT CONTROL LISTEO HEREON IS PROVIDED AS A COURTESY. IT IS THE RESPONSIBILIiY OF THE RECIPIENT TO VERIFY THE ACCURACY OF THE COORDINATES AND ELEVATIONS SHOWN PRIOR TO USING THEM FOR ANY PURPOSES. 3. ANY LOT LINES, RIGHTS OF WAY OR EASEMENTS SHOWN ARE APPROXIMATE AND ARE NOT TO BE RELIED UPON FOR FUTURE IMPROVEMENTS. GRADING NOTES: i. TOP OF POUNDATION MUST BE AT LEAST 6" ABOVE THE HIGHEST GRADE SURROUNDING ALL BUILDINGS. 2. THERE MUST 8E A MINIMUM GRADE OF 5% AWAY FROM THE BUILDINGS WITHIN THE EIRST 5 TO 10 FEET AOJACENT TO THE FOUNDATION. 3. SLOPES MUST NOT TO BE STEEPER THAN 339 (3:�). 0 0 0 Z EXISTING � /� HOUSE j// �-' � � WOOD DC-CK- � i �/// � / �� — �. , I h� w � �qg8��f5 ':-�RtTE-A��g839�f5 ' o 0 . . c -- �_}.. , o � . ��/ ,� z I �� \ � � / I � \ ~ � i � � � �i/ J �J ¢ F w � 6) I � �k9a RELOCATE EX I a � . � UTfL1TIES AS � 4gg3,g NECESSARY z G8�X GRADE BREAK 2% _ '_I W 4984.39 FS � I I - DS � —DS . ,�e�, � � 4984.39 �� , a I z% � FS' -1—�� ::'C�9$,�6) 4983G8 II N�. Co�NCLTIO a .. �� DS1I I'r _i � a —�d -' . 1 ?I I I W Z J F � W a O ¢ a � 1 I 29 � YI w I �Im w Ia �I�S � —20' 4983.8 GB� 4984.0� _4984.0 � - FG ' FG 4984.55 iFS 38.5 LF CONCREfE VALLEY PAN � 0.5% � (1' WIDE, 2' DEEP). PROPOSED GARAGE TOF=4984.55 � 2.5— 4984.0 I 6. FG 4984.0 � FG� � 5) �(�9a3 _ ii EX FENCE DOES NOT POLLOW PROPER'fY LINE e — _1 , � .4984.22 ` ° < � — — !+ 50.00' GFF � — - - - . N90°00'00"W a �,.Q° i� '=� . �. �, _ ,,; . _a. 18' CONC DRIVEWAY {`�� (49B3.36)� � � (4983.26J �7q) - FS � FS �� I_L�� lt�"�9 )� � i ��,t- TIE INTO EXISTING CONCREfE � 1005 - .. _ 4983.23 �i= �� - O�v ' . ` .. vsF � :�p.N k�c�, c :� I1/15/23 m: ; 39378 i �'ctc� �'•..... ' ��C; EXISTING RESIDENTIAL LOT PROPERTY LINE h� i �,�g8� ' �� 9S3 3� � (�(4983 4) 4983.8 4983.42 � - - - FL �. �4983.6 I � GB �(49832) � z �4983.39 = a z ` FL �3� o� �(4983.1) J � Qow 3 a wo � zo� � z a�z " � � a ��a 0 �w � 4983.6 FG �(4983 1) ,w; I \ �In�,f=� �4H ii 1, FS Zw� � 0 0 Jrp W Op�w Ym�.m� , �, � V I� 1� �� , Z Q � W 0 � � Q J� Z O 0 Q � Z J Z � N Q U H W Z Q � Q LL �a � � 1 OF 1