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HomeMy WebLinkAboutGrading Plans - 12/15/2020DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Grading/Stormwater Plan Accepted � (Building Permit Released) HIGHLAND Accepted by: Dan Mogen ,,; u„f Date: 12/15/2020 Ort O It1S DEVELOP'v'��NT SERVICES Memorandum T0: Dan Mogen — Fort Collins Utilities FROM: Jason Claeys, P.E. DATE: 11/04/20 PROJECT: 1819 W. Mulberry Street HDS JOB NO: 20-1022-00 SUBJECT: Drainage Summary This memo has been prepared to describe the existing drainage conditions along with the proposed improvements related to building remodel at 1819 W. Mulberry St (1819) and the shared driveway improvements with 1817 W. Mulberry St (1817). The existing property of 1819 W. Mulberry St is located along the south side of Mulberry and east of the New Mercer Canal irrigation ditch. The property drains from the northwest to the southeast to an existing inlet located on the neighboring property of 1817 W. Mulberry St. Both property's high points are the back of walk along Mulberry with all of the property runoff directed to the inlet in 1817. The existing inlet is approximately 6" deep and has a small pipe that exists to the south, though an outfall cannot be located. In discussing the condition of the inlet with the 1817 property owner and the 1819 owner rep, they believe that the pipe is clogged or collapsed downstream of the inlet and the area around the inlet ponds frequently during rainfall events. The inlet rim elevation is approximately 5055 ft and based on aerial topography, drainage relief occurs when the ponding reaches an elevation of 5056 ft, then drains to the east via overland flow. ��� � � �-2t � � i ; -= �'�-�.� _ � , •1 � � �� , � _ -�,;�;,. ,� r 'r' =-���'� ��.�- �� �� � �_ Existing Inlet Highland Development Services, Inc. 6355 Fairgrounds Avenue, Suite 100 � Windsor, CO 80550 � 970.674.7550 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St 11/4/20 Page2of3 The property owner of 1819 W. Mulberry St is proposing to rebuild and add an addition to the existing house/foundation along with adding a detached garage south of the house. The existing house has been removed and is proposed to use the existing foundation for the rebuild. Due to the existing drainage condition and ponding that occurs on the properties of 1819 and 1817, the runoff volume cannot be increased without making the ponding condition worse and increasing the potential of inundating the adjacent buildings. The owners of 1819 and 1817 have agreed to a shared driveway. With the reconstruction of the driveway, a high point is proposed approximately 26' south from the back of walk along Mulberry. The adjusted high point and proposed retaining wall at 1819 will direct approximately 3,036 sqft and the associated runoff to Mulberry St, rather than to the existing inlet. The reduction in area draining to the existing inlet is intended to allow the proposed improvements to occur while having no additional adverse impacts to the current drainage conditions. For the purposes of evaluating the existing and proposed drainage conditions, all of the 1819 and a portion of 1817 properties were analyzed in the drainage basin calculations. As previously mentioned, all of both properties drain to the existing inlet located on 1817. The analyzed existing area draining to the inlet is approximately 12,938 sqft and includes approximately 3,726 sqft of impervious area. The 100-yr peak runoff rate is estimated to be 1.67 cfs with an estimated runoff volume 2,213 cu-ft. The inlet is proposed to be removed and the drainage within the southern basin (Basin D2) will be directed to a graded depression and dry well. The area draining to the dry well is approximately 9,901 sqft, a 3,036 sqft reduction from existing, and includes approximately 4,283 sqft of impervious area, a 557 sqft increase. The 100-yr peak runoff rate is estimated to be 1.60 cfs, a 0.07 cfs reduction, with an estimated runoff volume of 2,143 cu-ft, an estimated reduction of 70 cu-ft. It should be noted that this analysis did not include all of the area draining to the graded depression and dry well and is in reference to the survey provided. There is additional area that drains to the dry well. The proposed drain pan within the shared driveway will direct runoff to a graded depression along the south side of 1819 and 1817. The drainage depression is proposed to be approximately 1.5 ft deep and will have a cumulative volume of 1,769 cu-ft. This storage will accommodate the runoff volume of the 2-yr and 10-yr storms, which have estimated runoff volumes of 571 cu-ft and 1,001 cu-ft, respectively. However, the depression will not accommodate the 100-yr storm, which has a runoff volume of 2,143 cu-ft. An 11 ft deep, 2 ft diameter dry well is proposed in the bottom of the depression to allow infiltration and some ponding relief. The dry well will extend 2 ft into the permeable layer. A soils report is attached for reference. When runoff volume exceeds the volume provided within the graded depression, in reference to the provided aerial topography, runoff will pond to an approximate elevation of 5056 ft before draining overland to the east as it has historically. It should be noted that the proposed graded depression and associated ponding volume will reduce the overflow rates and potentially reduce the 100-yr ponding elevation. The proposed dry well will promote infiltration and provide ponding relief. This drainage analysis has been completed to review and mitigate the impacts of the described improvements. Based on this analysis, the proposed improvements do not adversely impact the ocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St 11/4/20 Page3of3 existing drainage conditions and does not increase the volume of ponding and/or runoff rates. The proposed improvements and this analysis do not resolve the current ponding. Regional improvements are necessary to resolve the current ponding and are out of the scope of the proposed improvements and this analysis. The proposed structures at 1819 W. Mulberry Street have been elevated to provide a minimum of one (1) foot of freeboard above the assumed ponding elevation. Though the proposed improvements improve the existing drainage conditions, a 100-yr storm has the potential of inundating structures at 1817 W. Mulberry St. Due to the lack of an adequate outfall, both within the existing and proposed conditions, no guarantee is implied that the structures are protected from a 100-yr rainfall event. Acknowledgement: I acknowledge that the proposed improvements described within and shown on the "1819 W. Mulberry St — Grading & Drainage Plan" are estimated to not increase the existing ponding based on the provided documentation. It is understood that the proposed improvements do not alleviate the current potential of flooding during major rainfall events: 1819 W. Mulberry Street: CUocuSigned by: aSbin, �.t. ... Signature Jason Metzler Name 11/5/2020 Date DocuSigned by: C�� �4C� Teresa Metzler 11/5/2020 1R17 \A/ Miilharry Ctraat• DocuSigned by: C� ' / , � % �,—' 320729BSF39B44E... Signature Chapman Rose Name 11/4/2020 Date DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD782FB40D �' r EXISTING INE RIM=5055'± DRAINAGE ARROW (TYP) AERIAL TOPOGRAPHY (PROVIDED BY FORT COLLINS UTILITIES) NOT TO SCALE N� � �i T , n 6053 ? � � . ' �i ;},, . r. ,.;.� ���r . , ;I aE; '��' �: — � M;S� .� � « �Y � r ,�. w 4� �� 5��, ��`h� � �:` � �.I �, - _ �1��, � ' '�. �_ ; ��� ~ � e � �� �� � �i n � � _� �;, ' , �_'1 ``W �:;I�i�;�!l�u �` r j � ��('L,��"�'r ,+ � `� ���','' � 1'� �•�.' �' �Y �� ��- ' M ,�rl.:�� r--_ ' ' ��aa �I� '. i . t '��„ � � ��, # 1�� ' �� .�'�'�: • '� ,,,,�'�� _, . . � -�, �� � � ' t � . �'.. �r ` . ,�, �h } ,. F � � _ � \. ` ,,r. , •,, ... 1i� � . � . ~ '�� � . K � �.r �' I n � / � —'� ,� ti �." � �c - •,,. �� � �� ' ,�„'.' ' ;� j�' � ��`�� ,� ` �C°" �''. :� �..� r' � � M. �`"�t���� , w ,- . :i°i "�:r�''�� ~- � �-"' . �.vi,. ^a i `�_ ,�,{.,��Yy�q/S���i�. ���r��.� � _ �,'�'1�� � -- ----� f a r �,�"�+ t.. . ,�' � '�. _ � :� �. 1�,: y� ; . _ ' ��� � � ' _. � �. ; ' , �� ' s�s � � ' �. '� ° '��`� � � � r y�� �I � ' � � ' +�_ , � ' `�"". 1�1' 'p�se 4�I ' .r. , ��' , tr�"� a�� �,�� :� �"�, ,�► _� �� , . _ �` j— r � ` ''� + '� i �.. � : t� . �'� �d I � 7 ��J ,�µ���= 4 �/ . �I � , ' . . O / , . � . � . �� / � :� ��� ��; `j�f ��y �� ��,,�c� � _ ,,,,�; ba`�.�; �. � t3 �� M� , �a / �; , 7� a-• • y� �,, �' r�' o , ��' � .. � � , �.*'�- �+ r �'` f w. �' ;y •,�� � � � � :'�+ ' � w�" '� � � � I , T ;�:� � '"y " �,� `�' � , r � � � �� t-_ _ ;,� � � . - J _,� ,� � � � � �.,� — , r ,•� � ' ' � �' A � I . 181 7 �•,' � �_ — � � � I `�„�, � -�� ��� � �,`\ ' � , + / ��" � -� 1819 � H � <sr,s �� .. �� - ,.� . <;,^,,. '•.�„� �. , .� � :c � ; ►•�,�°"� , � . ; � .. -��` . _ =�+�',�'',�`� ., NORTH ,r ,�„ ;�� , .,R� �� �' �� �05' x. �*,"""' �"', '3i'!'. ``��`� ��;"_;'� ss� y . , � �� � ti , �'., � � � � � �� � Z905 � �� �'' . � DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD782FB40D � Hydrologic Soil Group—Larimer County Area, Colorado � � (1819 W. Mulberry St) � 0 0 490670 490C�7 490690 490700 490710 490720 40° 34' S5" N I I - --I 40° 34' S5" N � i�= _ -- - �i � � k _. � � � � -� �r � � '. �: � C .�, . � � •?. � t ► 4� i� M r1 �.. I �� a � �� � � �� � �— � � � � � ,,� , � - . . �_ �.. . � � ��� � � �' . , -. � � + ti t " �f� � ` � .� � � - � �' ,�-� T ' '� � I �;C�A�,:��1� i I`; � , . ., ��'� r�I^ • ^�.{ , �i 40° 34'S2"N _ i �_ _ I. I� _ I» � . >'� � I. � • � 490670 490680 490690 490700 490710 490720 3 � - Map S�le: 1:391 if printed on A portrait (8.5" x 11") sheet. ° N Meters � 0 5 10 ZO 30 � Feet 0 15 30 60 90 Map projection: Web Merrator Comer coordinates: WG584 Edge tics: UTM Zone 13N WG584 USDn Natural Resources Web Soil Survey � Conservation Service National Cooperative Soil Survey :�� _� � � �— � � � � . m � �� � � � o � � � � � � � ?� � ' 40° 34' S2" N 3 � m 0 8/20/2020 Page 1 of 4 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD782FB40D Hydrologic Soil Group—Larimer County Area, Colorado (1819 W. Mulberry St) MAPLEGEND Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons � A o �o 0 B � B/D 0 C 0 C/D � D � Not rated or not available Soil Rating Lines ,�y A o � ■ C/D � D 0 Not rated or not available Water Features Streams and Canals Transportation � Rails ti Interstate Highways US Routes Major Roads Local Roads Background - Aerial Photography �,� A/D ,.�� B ,..,,� si� . r C ..as C/D ,ry D . w Not rated or not available Soil Rating Points � A ■ A/D ■I B ■ I aio 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. USDa Natural Resources Web Soil Survey 8/20/2020 � Conservation Service National Cooperative Soil Survey Page 2 of 4 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Hydrologic Soil Group—Larimer County Area, Colorado Hydrologic Soil Group 1819 W. Mulberry St Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 74 Nunn clay loam, 1 to 3 C percent slopes �. 100.0% Totals for Area of Interest Description 0.6 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 100.0% USDa Natural Resources Web Soil Survey 8/20/2020 � Conservation Service National Cooperative Soil Survey Page 3 of 4 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Hydrologic Soil Group—Larimer County Area, Colorado Tie-break Rule: Higher 1819 W. Mulberry St USDA Natural Resources Web Soil Survey 8/20/2020 � Conservation Service National Cooperative Soil Survey Page 4 of 4 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D • ' � l N C O!� O t A T■ 0 October 2, 2020 Forge and Bow 116 North College Avenue, Suite 5 Fort Collins, Colorado 80524 Attention: Alexandra Henze Subject: Permeability Tests 1819 Mulberry Street Fort Collins, Colorado CTL�T Project Number: FC09580-120 CTL�Thompson, Inc. was asked to determine the hydraulic conductivity of the soils at the subject address. We understand that a dry well is being considered on the lot to provide infiltration of stormwater runoff. The field investigation included drilling one exploratory boring at the approximate center of the lot as presented on Figure 1. The boring was drilled to a depth of approximately 15 feet using 4-inch diameter, continuous-flight augers and a truck- mounted drill. Drilling was observed by our field representative who logged the soils. A summary log of the boring, including results of field penetration resistance tests, is presented on Figure 2. Particle size analysis results are presented on Figure 3. Subsurface conditions encountered in our boring consisted of 9 feet of clayey/silty sand over well graded, clean to slightly clayey, sand and gravel to the depth explored. Groundwater was measured at a depth of 8'/2 feet. In-situ permeability testing was conducted at the boring by adding water in the hole and measuring the drop in the water level over time. Based on our testing, we determined a hydraulic conductivity of 0.7 cm/s. Based on our experience and literature, we believe the measured hydraulic conductivity is appropriate for the granular materials encountered. We appreciate the opportunity to work with you on this project. Please do not hesitate to contact us with any other questions or concerns. Sincerely, CTL�THOMPSON, INC. .%,�-, 1'�.,--_ Trace Krausse, EI Project Geotechnical Engineer 5pencer 5cnram, rt Geotechnical Department Ma a er �p�ncer Schran� Oct 2 2020 2:05 PM 400 North Link Lane � Fort Collins, Colorado 80524 Telephone:970-206-9455 Fax:970-206-9441 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD782FB40D APPROXIMATE SCALE: 1" = 50' 0' 25' 50' LEGEND: TH-1 INDICATES APPROXIMATE � LOCATION OF EXPLORATORY BORING � 1 � West Mulberry Street � `�` - r - _ ,o. I :->. � ., �.. ' �.a , :. °� - , . � . _,- � � , _-� +� , i , � ' f� .. , ,. . � �► F � ,y�, � ,,. � � , .. . �'T� � . � � ,� .�� ,.-. � TH-1 �i � . . . } �� • � , - ( � � ,� . � � FORGE AND BOW 1819 WEST MULBERRY STREET CTL I T PROJECT NO. FC09580-120 s�_ . :{ .� ;-�' � ,_ _ `�f�`,,. �� i .� �:::: �W Location of Exploratory Boring FIGURE 1 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D � HYDROMETER ANALYSIS SIEVE ANALYSIS 25 HR. 7 HR. TIME READINGS U.S. STANDARD SERIES CLEAR SQUARE OPENINGS 45 MIN. 15 MIN. 60 MIN. 19 MIN. 4 MIN. 1 MIN. '200 `100 `50 '40 '30 '16 '10 `8 `4 3/8" 3/4" 1%" 3" 5" 6" 8" 100 � I p 90 — 10 80 �I�— - - - 20 Z �� �i �i 30 Z N I I Q a 60 ! I I 40 w � � F w 50 —I� ,�. .I. — - 50 w � � U W � a 40 -'� 60 a 30 � �. �: .�; �'��-. �. .. -:...— 70 I 20 I I � 80 ' I 10 90 I ' I p �� � ',, ',. .100 .001 0.002 .005 .009 .019 .037 .074 .149 .297 .590 1.19 2.0 2.38 4.76 9.52 19.1 36.1 76.2 127 200 0.42 152 DIAMETER OF PARTICLE IN MILLIMETERS Sample of SAND, GRAVELLY, SLIGHTLY CLAYEY (SW-SC From TH - 1 AT 9 FEET FORGE AND BOW 1819 MULBERRY STREET PERMEABILITY TESTING CTL � T PROJECT NO. FC09580-120 GRAVEL 4� % SAND 5� % SILT & CLAY g % Gradation Test Results FIGURE 1 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D � � Know what s beloW � Cdll before you d�g 200' EXISTING DIA GRADE �-- --- 4 DRY � � 1 WELL PROPOSED ELEV = 5054.31 GRADE 1" LANDSCAPE J �� 11.00' COBBLE BEGINNWG OF PERMEABLE LAYER 24" PVC PIPE EXTEND DRY WELL 2.00' INTO PERMEABLE LAYER (PERFORATE BOTTOM 2', Yi' HOLES, 4" O.C. DRY WELL DETAIL N TS z W � 3 ,� 5 � ,� SCALE 1"= 10' 20 NOTES: I. iH15 PLAN HAS 9EEN PREPARE� i0 RE EQUAL i0 AN�/OR IMPROVE iHE �RAINAGE CONDIiIONS iHnt E%ISTATSHARED INLEf Ai 181] W.M�LBERRYST �IBI)� WHILEALLOWINGTHEPROPOSED iMPROVEMENfS Al' 1819 W. MULBERRY Si �1819� i0 OCCUR. iHE PROPOSED IMPROVEMENiS ARE ESTIMAiED i0 RE�IICE STORM Rl1NOFF QUANiIiIES, PROVIDE ADDITIONAL PONOING AREA/VOLUME AND A DRV W ELL i0 ASSISi IN PONDING RELIEF iHROUGH INFILTRATION. 2. BASEDONESiIMATESOFiHEEXISTINGCONDITIONSANDREVIEWOFTHEAVAILABLEAERIAL tOPOGRAPrIY. li iS ESiIMAt[D iHAI PONDING DURING n SiORM EVENi REACHES i0 AN ELEVAiIOn OF 5056 Fi PRIOR 10 DRAINING EASI VIA OVERLAND FLOW. 3. iHE PftGPOSED SiRtICiURES Ai IBi9 HAVE BEEN CLEVAiED t0 PROVI�E A nnlNlrnUM O� I Fi Of FREEBOARD ABOVE iMS ASSUMEU PONDING ELC-VAiION_ 4_ iHOUGH iHE PROPOSEO Ir�nPROVEMENi51MPROVE �HE E%ISiING DRAINnGE CONDIiIONS. A I(10 VR SiORM HAS THE P9iENTIAL OF INUNDATING SiRUCiURES AT 18 i 7 W. MULBERRY S7. �UE i0 T�1E LACK OF AN ADEOUATE Ol1iFALL W ITHIN BOiH EXISTING AND PROPOSED CONOIiIONS. NO GUAeqNTEE IS IMPLIED 1HA1 �HE SiRUCi'URES ON I81 / ARE PkOiPC1N FROM A I DO-YR S�C�RM. REFERFNCP iH["1819 W. MlIL9ERFY $iRELI � �RAIIVAGE SUMMARY"MEMORANDUM. DAIED 11/04/20. AND CALCULAIIONS BELOW. 5. Ph�OVIDE A MINIMUM OG 5% SLOPEAWAY FROM FOUNDAiIONS FOR iHE FIRSi 5 i0 10'T. BASINS: "�, I mperviouz val ues from Ta ble PO 11 �in Me Fort Coll �i nz Amendmen[s to the tlrba n Dra �inaCe ar.c Flootl Conaol ��isttict Criteria Ma r��al Rur�off Coefficienn a ntl Frecuer.cy Pdjustment Faaors for Ciry of Fort Colli ns � Smrm Wamr Crireria Ma nua I W. RunaH Renm Frequenry tand Uu Adjurtment Mvermou: coemaene c re.ma vxxo.141 Paved 100% 095 �-Yearto 1.00 10-yex Roof 9pY 095 100ryear 1.25 Walks 90% 095 Gavel/Pavers 40% O50 Lawns (Heavy, 3�Nh Slope� �y0 0 25 Sub�6asin qaa 11uin !y,„a A.,,r A„.nk /1p.,.Yr.�.� A�.�• Weigh[ed� �OMPOSRE Desipia�ion (sqMet) (sres) (sqfeet) �sqfcc�) (sqleet� (sqfcei) �sqfeet) ImpeMous �to��o 4m � � �� � I 10.00' DRAINAGE ESMT I _ — _ _ _ — — � _ _ — _ _ _ _ _ ' _ _ _ ,7B77 W. MULBERRY ST 75.00' FRAME HOUSE � � � � � � �SHARED ACCESS & � � � � > > � � � � � � � � � � � � � � � x� � — — — — — — — — FFE=5056.3i� — — — — — — DRAINAGE ESMT FRAME GARAG£ �L� I I � � � J � � �� -- ssos � � ' H2 I INLET , _ _ _ _, � � � _ _ _ _ _ _ _ _ CRA TE 5054.9B I � lNV 5=5054.45 _ _ — _ _ L _ — _ `_Y � x — � v — .� v _ X_ —X— ' � — — — � — — — — — — (TO 8E REMOVED) — — — L — — — — — — — � I * � —J � �2s.n'� I I �i 7 I � N I' � � � � �, I I 1 m I' I I I � �, — — = I 3 i Ii' � 1 570RY FRAME � �% H 2 I tN1 I; FF=soszs � o.ao ass i I o.os i.00 � � � � _ � �- ------� I � I, � I I � � � 10' X 12' � ` FRAME ' SHED I r r i _-�_-_'_-�i-�_-_-_-_-_-�_�� ��-_�-�_-_-��_-_-_-_-���_-���_-_--,-��_-_��_ I I ��� X X X� X X X- k) �X� X—X X�—X--X- X X X X X X- I I HISTORIC � I I � � I � t � � � � � � � � � � � � � � � � 0� i � ��/��SS.BB EX �.q% 56.4� � 56.f0 EX-Y � i ' I ?2e 56.45 8.1% _ — _ _' � � _ — _ — �55.89 � I o � c 5614 EX � I —56.32 EX 0.5%� ■ I 26.77• 56.45� �.�� I * I 58.68�� I � II I � \ RETAINING WALL I y I I (HEIGHT VARIES) � II I 1 W � I� \ y� —� I m � I h� II _ _ � I � I 3 'f ^I I �; I , D1 \ � _ : I � 0.12 0.91 I Sps, L_II �( � If \ �I � o \I J � � S \ I I � � sa �.�� I�56.68— � � � �� � -'�—�--�__N—� 56.]0�= �_ BASIN SUMMARY: � I 5B.33 EX�� � I� DEVELOPED � yb -----� � �° ,- -, � , , I ; '� I I � DRAINAGE ESMT�I I . I ' 1 � 4:1 I d � I � �� � , � � - � � � � � W � � � 1� F� � l� � l� PR���.uFD Br9x �ni�ENI:�E Dik� Su� �aysiory c�. Foa rrin �m aF�ni F oF wcH�n��o DEVE�orM.ENrSEFucEs DATE Il/4/20 $CALE �HJ 1"= 10' SCALE (V) N/A DRo.wN Bv JTC CHECKEo BY JTC HDS PRo�ECi?+ 20-1022-00 SHEET � OF � DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St DEVELOPED IMPERVIOUS AREA CALCULATION Design Engineer: J.Claeys Design Firm: Highland Development Services Project Number: 20-1022-00 Date: DESIGN CRITERIA: August 21, 2020 Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual BASINS: % Impervious values from Table RO-11 in the Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual Runoff Coefficients and Frequency Adjustment Factors for City of Fort Collins - Storm Water Criteria Manual Land Use � Runoff Impervious Coefficient C Paved 100% 0.95 Roof 90% 0.95 Walks 90% 0.95 Gravel/Pavers 40% 0.50 Lawns (Heavy, 2-7% Slope) 0% 0.25 Frequency Return Adjustment Period Factor (C ) 2-year to 1.00 10- ear 100-year 1.25 Sub-basin Atotal Atotal Apaved Aroof Awalk Agravel/pavers Alawn Weighted % COMPOSITE Designation (sq feet) (acres) (sq feet) (sq feet) (sq feet) (sq feet) (sq feet) Impervious CZto Clo ��oo H1 2,152 0.049 2,152 0 0 0 0 100.0% 0.95 1.00 H2 12,938 0.297 1,664 1,776 286 0 9,211 27.2% 0.45 0.56 D1 5,188 0.119 2,521 878 134 0 1,656 66.1% 0.73 0.91 D2 9,901 0.227 1,565 2,719 0 584 5,034 42.9% 0.57 0.71 D2 vs. H2 -3,036 -0.070 557 1819 W. Mulberry - Rational Calcs (FC) (Updated).xlsx Page 1 of 1 Highland Development Services DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St PEAK RUNOFF Design Engineer: J.Claeys Design Firm: Highland Development Services Project Number: 20-1022-00 Date: August 21, 2020 DESIGN CRITERIA: Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual The time of concentration (t� ) is assumed to be 5 min EQUATIONS: Q„ = n -yr peak discharge (cfs) = C„I�� A C„ = n-yr runoff coefficient �" " I„ = n -yr rainfall intensity (in/hr) A„ = Basin drainage area (ac) 28.SP, � 10.7H6657) �l�+t�� 1 = rainfall intensity (in/hr) P 1= one-hour point rainfall depth (in) t� =time of concentration (min) P1_2yr = 0.82 In P1-loy, = 1.40 in Pi-iooY. = 2.86 in BASIN SUMMARY: 2-yr Peak Runoff 10-yr Peak Runoff 100-yr Peak Runoff Design Sub-basin Area (acres) Runoff Coeff Intensit Runoff Coeff Intensit Runoff Coeff. Intensit Point t� (min) ��z-lo) CIA) (acres) (in/hr�Y Q (ft3/s) t� (min) (�z-io) �IA) (acres) (in/hr)Y Q (ft3/s) t� (min) (Cloo) �IA) (acres) (in/hr�Y 41ft3/s) H7 Hl 0.049 5.00 0.95 0.05 2.85 0.13 5.00 0.95 0.05 4.57 OZ3 5.00 1.00 0.05 9.95 0.49 H2 H2 O.297 5.00 0.45 0.13 2.85 038 5.00 0.45 0.13 4.87 0.65 5.00 0.56 0.17 9.95 1.67 Dl D1 0.119 5.00 0.73 0.09 2.85 0.25 5.00 0.73 0.09 4.87 0.42 5.00 0.91 0.11 9.95 1.08 D2 D2 0.227 5.00 0.57 0.13 2.85 037 5.00 0.57 0.13 4.87 0.63 5.00 0.71 0.16 9.95 1.60 1819 W. Mulberry - Rational Calcs (FC) (Updated).xlsx Page 1 of 1 Highland Development Services DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St 100-yr Detention Volume - FAA Method Design Engineer: J.Claeys Design Firm: Highland Development Services Project Number: 18-1000-00 Date: August 21, 2020 DESIGN CRITERIA Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual City of Fort Collins - Storm Water Criteria Manual Existing Runoff Volume Calculation - No Outlet (Basin H2) Runoff Coefficient (C ) 0.45 Frequency Factor (C,) 1.25 Required Detention Adjusted Runoff Coefficient (CCf) 0.56 ft3 acre-ft Area (A ) 0.297 acres 2,213 0.05 Allowed Release Rate 0.00 cfs 100-yr Accumulative Kelease Detained Detained Time Intensity Q�oo Runoff Volume Volume Volume Volume (min) (/, in/hr) (cfs) (ft3) (ft3) (ft3) (acre-ft) 0 0.00 0.00 0 0 0 0.00 5 9.95 1.66 499 0 499 0.01 10 7.72 1.29 774 0 774 0.02 15 6.52 1.09 980 0 980 0.02 20 5.60 0.94 1,123 0 1,123 0.03 25 4.98 0.83 1,248 0 1,248 0.03 30 4.52 0.76 1,359 0 1,359 0.03 35 4.08 0.68 1,431 0 1,431 0.03 40 3.74 0.62 1,500 0 1,500 0.03 45 3.46 0.58 1,561 0 1,561 0.04 50 3.23 0.54 1,619 0 1,619 0.04 55 3.03 0.51 1,670 0 1,670 0.04 60 2.86 0.48 1,720 0 1,720 0.04 65 2.72 0.45 1,772 0 1,772 0.04 70 2.59 0.43 1,817 0 1,817 0.04 75 2.48 0.41 1,864 0 1,864 0.04 80 2.38 0.40 1,909 0 1,909 0.04 85 2.29 0.38 1,951 0 1,951 0.04 90 2.21 0.37 1,994 0 1,994 0.05 95 2.13 0.36 2,028 0 2,028 0.05 100 2.06 0.34 2,065 0 2,065 0.05 105 2.00 0.33 2,105 0 2,105 0.05 110 1.94 0.32 2,139 0 2,139 0.05 115 1.89 0.32 2,179 0 2,179 0.05 120 1.84 0.31 2,213 0 2,213 0.05 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St 2-yr Detention Volume - FAA Method Design Engineer: J.Claeys Design Firm: Highland Development Services Project Number: 20-1022-00 Date: August 21, 2020 DESIGN CRITERIA Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual City of Fort Collins - Storm Water Criteria Manual Proposed Runoff Volume Calculation - No Outlet (Basin D2) Runoff Coefficient (C ) 0.57 Frequency Factor (C,) 1.25 Required Detention Adjusted Runoff Coefficient (CCf) 0.71 ft3 acre-ft Area (A ) 0.227 acres 571 0.01 Allowed Release Rate 0.00 cfs 2_yr Accumulative Release Detained Detained Time Intensity Q2 Runoff Volume Volume Volume Volume (min) (/, in/hr) (cfs) (ft3) (ft3) (ft3) (acre-ft) 0 0.00 0.00 0 0 0 0.00 5 2.85 0.46 138 0 138 0.00 10 2.21 0.36 214 0 214 0.00 15 1.87 0.30 272 0 272 0.01 20 1.61 0.26 312 0 312 0.01 25 1.43 023 347 0 347 0.01 30 1.30 0.21 378 0 378 0.01 35 1.17 0.19 397 0 397 0.01 40 1.07 0.17 415 0 415 0.01 45 0.99 0.16 432 0 432 0.01 50 0.92 0.15 446 0 446 0.01 55 0.87 0.14 464 0 464 0.01 60 0.82 0.13 477 0 477 0.01 65 0.78 0.13 492 0 492 0.01 70 0.73 0.12 496 0 496 0.01 75 0.70 0.11 509 0 509 0.01 80 0.66 0.11 512 0 512 0.01 85 0.64 0.10 528 0 528 0.01 90 0.61 0.10 533 0 533 0.01 95 0.58 0.09 535 0 535 0.01 100 0.56 0.09 543 0 543 0.01 105 0.54 0.09 550 0 550 0.01 110 0.52 0.08 555 0 555 0.01 115 0.51 0.08 569 0 569 0.01 120 0.49 0.08 571 0 571 0.01 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St 10-yr Detention Volume - FAA Method Design Engineer: J.Claeys Design Firm: Highland Development Services Project Number: 20-1022-00 Date: August 21, 2020 DESIGN CRITERIA Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual City of Fort Collins - Storm Water Criteria Manual Proposed Runoff Volume Calculation - No Outlet (Basin D2) Runoff Coefficient (C ) 0.57 Frequency Factor (C,) 1.25 Required Detention Adjusted Runoff Coefficient (CCf) 0.71 ft3 acre-ft Area (A ) 0.227 acres 1,001 0.02 Allowed Release Rate 0.00 cfs 10-yr Accumulative Kelease Detained Detained Time Intensity Q�o Runoff Volume Volume Volume Volume (min) (/, in/hr) (cfs) (ft3) (ft3) (ft3) (acre-ft) 0 0.00 0.00 0 0 0 0.00 5 4.87 0.79 236 0 236 0.01 10 3.78 0.61 367 0 367 0.01 15 3.19 0.52 464 0 464 0.01 20 2.74 0.44 532 0 532 0.01 25 2.44 0.39 592 0 592 0.01 30 2.21 0.36 643 0 643 0.01 35 2.00 0.32 679 0 679 0.02 40 1.83 0.30 710 0 710 0.02 45 1.69 027 738 0 738 0.02 50 1.58 0.26 767 0 767 0.02 55 1.48 024 790 0 790 0.02 60 1.40 0.23 815 0 815 0.02 65 1.32 021 833 0 833 0.02 70 1.25 0.20 849 0 849 0.02 75 1.19 0.19 866 0 866 0.02 80 1.14 0.18 885 0 885 0.02 85 1.09 0.18 899 0 899 0.02 90 1.05 0.17 917 0 917 0.02 95 1.01 0.16 931 0 931 0.02 100 0.97 0.16 941 0 941 0.02 105 0.94 0.15 958 0 958 0.02 110 0.91 0.15 971 0 971 0.02 115 0.88 0.14 982 0 982 0.02 120 0.86 0.14 1,001 0 1,001 0.02 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D 1819 W. Mulberry St 100-yr Detention Volume - FAA Method Design Engineer: J.Claeys Design Firm: Highland Development Services Project Number: 20-1022-00 Date: August 21, 2020 DESIGN CRITERIA Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual City of Fort Collins - Storm Water Criteria Manual Proposed Runoff Volume Calculation - No Outlet (Basin D2) Runoff Coefficient (C ) 0.57 Frequency Factor (C,) 1.25 Required Detention Adjusted Runoff Coefficient (CCf) 0.71 ft3 acre-ft Area (A ) 0.227 acres 2,143 0.05 Allowed Release Rate 0.00 cfs 100-yr Accumulative Kelease Detained Detained Time Intensity Q�oo Runoff Volume Volume Volume Volume (min) (/, in/hr) (cfs) (ft3) (ft3) (ft3) (acre-ft) 0 0.00 0.00 0 0 0 0.0000 5 9.95 1.61 483 0 483 0.0111 10 7.72 1.25 749 0 749 0.0172 15 6.52 1.05 949 0 949 0.0218 20 5.60 0.91 1,087 0 1,087 0.0250 25 4.98 0.81 1,208 0 1,208 0.0277 30 4.52 0.73 1,316 0 1,316 0.0302 35 4.08 0.66 1,386 0 1,386 0.0318 40 3.74 0.60 1,452 0 1,452 0.0333 45 3.46 0.56 1,511 0 1,511 0.0347 50 3.23 0.52 1,567 0 1,567 0.0360 55 3.03 0.49 1,617 0 1,617 0.0371 60 2.86 0.46 1,665 0 1,665 0.0382 65 2.72 0.44 1,716 0 1,716 0.0394 70 2.59 0.42 1,759 0 1,759 0.0404 75 2.48 0.40 1,805 0 1,805 0.0414 80 2.38 0.38 1,848 0 1,848 0.0424 85 2.29 0.37 1,889 0 1,889 0.0434 90 2.21 0.36 1,930 0 1,930 0.0443 95 2.13 0.34 1,964 0 1,964 0.0451 100 2.06 0.33 1,999 0 1,999 0.0459 105 2.00 0.32 2,038 0 2,038 0.0468 110 1.94 0.31 2,071 0 2,071 0.0475 115 1.89 0.31 2,109 0 2,109 0.0484 120 1.84 0.30 2,143 0 2,143 0.0492 DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Forge+Bow � Metzler � Rose - Drainage Plan Cost Summary OWNER Jason and Teresa Metzler 1819 W Mulberry Street Fort Collins, CO 80521 OWNER Chapman Rose 1817 W Mulberry Street Fort Collins, CO 80521 CONTRACTOR Property Inc., LLC DBA Forge+Bow Dwellings 116 N College Ave, Suite 5 Fort Collins, CO 80524 COST SUMMARY The tables below summarize costs associated for each property as described in the Plan Documents. The structure of payment to Contractor is to be a Stipulated Sum "Flat Fee" — both Owners shall agree to pay the Contractor (Forge+Bow Dwellings) the Cost of Work in current funds for the Contractor's performance of the drainage plan and description of work below. Contractor shall seek additional bids for concrete flatwork before work is performed and submit a reductive change order to the Owners, if lower cost can be achieved. The Owners understand that the Contractor cannot guarantee lower costs and agree to pay Contractor for costs as summarized below for all work completed. Costs Shared EquallX Shared costs between the parties for the execution of the drainage plan for both lots are split 50/50 between the Owners and include the following: Dry-wel I Soils Test Driveway Pan Final Drainage Plan Engineering Pumping DS �C(�1 � �` DS 1� " DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Additional Costs - Metzler Includes preliminary drainage engineering fees, site survey costs, removal of existing concrete driveway, 13 tons of gravel, and a concrete apron approximately120 SF in front of the new garage location according to the drainage plan. Additional Costs - Rose Costs associated with concrete flatwork are split 55 (Chapman Rose) / 45 (Jason and Teresa Metzler). There is more concrete square footage removal and new pour on Chapman Rose's property. The additional work and costs for Rose includes the following (not depicted on the drainage plan and memo drawings): Existing concrete, approximately 657 SF in front of garage to be removed as well as 216 SF of dirt removal on east side of current concrete pad. 876 SF of new concrete to be poured to replace both the existing concrete in front of the garage as well as the existing grass area east of existing concrete. 77 SF of new concrete to be poured from new driveway to front following removal of existing pathway. DS � �DS �C� � � � DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Rose Cost Summary Drainage Costs - Rose Cost Site Observation and Grading Plan (Carson) $ - Topographic Survey (Majestic) $ - Preliminary Drainage Plan (Keefe) $ - Drywell $ 5,250.00 Soils Test $ 850.00 Driveway Pan $ 1,650.00 Foundation Increase $ - Engineering/Highland Development $ 1,500.00 Original Drainage Plan $ - Total $ 9,250.00 Driveway Related Costs - Rose Cost Gravel Driveway w/ Concrete Apron $ - Concrete Removal (Metzler Side Driveway) $ - Driveway Removal for New Pan $ 1,932.00 Concrete Driveway $ 5,055.00 Garage Pad Flatwork (includes concrete removal) $ 8,733.60 Front Walkway Flatwork (includes concrete remova $ 646.80 Pumping $ 890.40 Total $ 17,257.80 NOTE: Items highlighted green do not have Contractor markup applied. Items highlighted blue do include Contractor markup in the cost listed. DS -DS �I`C� ; �,,-, � DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D Metzler Cost Summary Drainage Costs - Metzler Cost Site Observation and Grading Plan $ 250.00 Topographic Survey $ 850.00 Preliminary Drainage Plan $ - Drywell $ 5,250.00 Soils Test $ 850.00 Driveway Pan $ 1,650.00 Foundation Increase $ 1,578.00 Engineering/Highland Development $ 1,500.00 Original Drainage Plan $ 1,512.00 Total $ 13,440.00 Driveway Related Costs - Metzler Cost Gravel Driveway w/ Concrete Apron $ 2,323.20 Concrete Removal (Metzler Existing Driveway) $ 2,162.40 Driveway Removal for New Pan $ 1,296.00 Concrete Driveway $ 4,192.50 Chap Flatwork $ - Chap Front Walkway $ - Pumping $ 890.40 Total $ 10,864.50 NOTE: Items highlighted green do not have Contractor markup applied. Items highlighted blue do include Contractor markup in the cost listed. DS ' -DS �1`Cr'1 � r� � DocuSign Envelope ID: 726F6E27-D6B5-4531-BCFA-4ADD7B2FB40D The Owners hereby agree to the costs and scope outlined in the cost summary and depicted on the grading and drainage memo. By signing below, Forge+Bow is given permission to proceed with executing the plan and invoicing as described above for the work. CDocuSigned by: aSbin, �l.c.{-�� ssoeisozocs�ass... Owner - Jason Metzler DocuSigned by: .��� qj q�� Owner - Teresa Metzler DocuSigned by: ���.�/�-� 320729BSF39B44E... Owner - Chapman Rose DocuSignetl by: C���.�, r���i/ta/�. — 79353851CB92429... Owner - Jordan Obermann 11/5/2020 Date 11/5/2020 Date ii�4�zozo Date 11/5/2020 Date Forge + Bow � y RECEPTION #20200100020, 12/12020 4 43:40 PM, 1 of 10, $58.00 Angela Myers, Clerk � Recorder, Larimer County, CO tip DECLARATION OF PRNATE EASEMQ�TT AND MAINTENANCE AGREEMENf That the imdersigned, being the owner(s) of certain rcal property in Larimer Co�mty, Colorddo legally described as: Pazcel Number: 9715201002 (COM AT PT 1368.5 FT E OF NW COR 15-7-69_ TH S 218 FT: TH S 89 40' E 55 PT: TH N 218 FT� TH N 89 40' W 55 FI' TO BEG FTCI �nd 1 NL*�ber- 9715201003 (COM AT A PT 1423.5 FLE OF NW COR 15-7-69_ S 218 FT_ S 89 40' E 60 FT_ N 218 FT_ N 89 40' W 60 FT TO BEG. FTC) dces hereby dedicate a permanent easement for the purpose of drainage in the Cily of Fort Collins, County of Larimer, State of Colorado, more particularly described on Exhibit "A" attached heteto and by ttus reference macie a parl hereof (the "EasemenY'). T'his Declaration of Private �asement and Maintenance Agreement ("Declaration") is made effective as of the date reconied with the Clerk and Recorder of Larimer Coimty, Colorado ("Clerk and Recorde�') between the • _ �� �c _ � • . • . � � ,n��� .-� '' _ The Parties' tights under lhe Easement include the right to ins�ll, operale, access, maintain, repair, reconsttuct, remove and replace within the Easement private improvements consistent with the intended purpose of the Easement the right to mark the location of the Easement with suitable mazkeis; and the right to permit other public utilities to exercise these same rights. The Owners of both properties are jointly responsible, at their sole cost, for maintenance, repair, and replacement of the drywell. The drywell is intended to provide ponding relief through infiltration with the use of a 24inch diameter vertical PVC pipe extending into the pecmeable layer, lhe pipe extending a minimum of 11 ft below grade, with pipe perforalion within the bottom section of the pipe. Reference the "1819 W. Mulberry Street — Drainage Siunmary" memorandum, E�chibit "B", dated I 1/04l20, for fiuther description and detail of the dry well and drainage impmvements. As nceded to maintain the performance of the drywell, lhe Owners will work cooperalively and joinfly to determine the drywell maintenance and repair work to be done as well as the timing and cost of such work. The costs of maintaining and repairing the drywell will be shared equally between the Owners of boih properties. To maintain and extend the usefW life of the drywell, maintenance will include: removal of JALEX HENZE 427 BUCKEYE ST FORT COILINS, CO 80524 � �dimentation upstream of the drywell, regular inspection of the dry well to evaluate pedormance, regular removal of accumulated sediment from within the dry well, removal and replacement of stone within the dry well as needed if the stone becomes cloggeci with debris and sediment, and the removal and replacement of the dry well (perforated verticsil PVC pipe, mck, surmunding native material) when nceded due to the syslem being cloggeci or damaged und restored back to the intended condilion. The graded depression surrounciing the dry well is intended tn provide runoff ponding volume away from and reduce the risk of in�mdating the stn�cttues at 1817 W. Mulberry Street� The gmding/elevations of the depression and dry wcll, as shown in the "1819 W. Mulberry St — Grading & Drdinage Plan", dated I 1/4/20, shall be maintained without increasing the risk of flooding structures. Any modiGcation to the grading shall be immediately restored to the design elevations. �C�] �I�I�It7 Name: Jason Metzler Adciress: 1819 West Mulbeay Street, Fort Collins, Colorado 80521 OWNER Name: Teresa Metzler Address: 1819 West Mulberry Street, Fort Collins, Colorado 80521 The foregoing instrument was acknowledged before me this � day of .N�,I�2020, by Ja�o�, �'lerrsa l�ter�s ��1�'r1f1JV' . �a ('��mp�,��S� � Q�J✓nQii� . Witness my and otlicial seal. My commission expires: Z�Z/i' �Q,l�ifl�l9/}�' �ll.l,�i1M `S� d-�-�d (('l1ro�d.�i �1 � Notary Public KAILEE THARNISH NOTARY PUBLIC STATE OF COLORADO NOTARY ID 20204022983 MY COMMISSION EXPIRES 07-02-2024 Address: 1817 West Mulbetry�treet, Fort Collins, Colorado 80521 � I 1IGHLAND � UF�di �iJi�r,�c,.� � � 6���:��( ! �� Memorandum TO: FROM: DATE: PROJ ECT: HDS JOB NO SU BJ ECT: Dan Mogen — Fort Collins Utilities Jason Claeys, P.E. 11/04/20 1819 W. Mulberry Street 20-1022-00 Drainage Summary rOv U:� L/ ,%�i��''� . .� .� . � ..n�'���� This memo has been prepared to describe the existing drainage conditions along with the proposed improvements related to building remodel at 1819 W. Mulberry St (1819) and the shared driveway improvements with 1817 W. Mulberry St (1817). The existing property of 1819 W. Mulberry St is located along the south side of Mulberry and east of the New Mercer Canal irrigation ditch. The property drains from the northwest to the southeast to an existing inlet located on the neighboring property of 1817 W. Mulberry St. Both property's high points are the back of walk along Mulberry with all of the property runoff directed to the inlet in 1817. The existing inlet is approximately 6" deep and has a small pipe that exists to the south, though an outfall cannot be located. In discussing the condition of the inlet with the 1517 property owner and the 1819 owner rep, they believe that the pipe is clogged or collapsed downstream of the inlet and the area around the inlet ponds frequently during rainfall events. The inlet rim elevation is approximately 5055 ft and based on aerial topography, drainage relief occurs when the ponding reaches an elevation of 5056 ft, then drains to the east via overland flow. Highland Development Services, Inc. 6355 Fairgrounds Avenue, Suite 100 � Windsor, CO 80550 � 970.674.7550 Existing Inlet � 1819 W. Mulberry St 11/4/20 Page 2 of 3 The property owner of 1819 W. Mulberry St is proposing to rebuild and add an addition to the existing house/foundation along with adding a detached garage south of the house. The existing house has been removed and is proposed to use the existing foundation for the rebuild. Due to the existing drainage condition and ponding that occurs on the properties of 1819 and 1817, the runoff volume cannot be increased without making the ponding condition worse and increasing the potential of inundating the adjacent buildings. The owners of 1819 and 1817 have agreed to a shared driveway. With the reconstruction of the driveway, a high point is proposed approximately 26' south from the back of walk along Mulberry. The adjusted high point and proposed retaining wall at 1819 will direct approximately 3,036 sqft and the associated runoff to Mulberry St, rather than to the existing inlet. The reduction in area draining to the existing inlet is intended to allow the proposed improvements to occur while having no additional adverse impacts to the current drainage conditions. For the purposes of evaluating the existing and proposed drainage conditions, all of the 1819 and a portion of 1817 properties were analyzed in the drainage basin calculations. As previously mentioned, all of both properties drain to the existing inlet located on 1817. The analyzed existing area draining to the inlet is approximately 12,938 sqft and includes approximately 3,726 sqft of impervious area. The 100-yr peak runoff rate is estimated to be 1.67 cfs with an estimated runoff volume 2,213 cu-ft. The inlet is proposed to be removed and the drainage within the southern basin (Basin D2) will be directed to a graded depression and dry well. The area draining to the dry well is approximately 9,901 sqft, a 3,036 sqft reduction from existing, and includes approximately 4,283 sqft of impervious area, a 557 sqft increase. The 100-yr peak runoff rate is estimated to be 1.60 cfs, a 0.07 cfs reduction, with an estimated runoff volume of 2,143 cu-ft, an estimated reduction of 70 cu-ft. It should be noted that this analysis did not include all of the area draining to the graded depression and dry well and is in reference to the survey provided. There is additional area that drains to the dry well. The proposed drain pan within the shared driveway will direct runoff to a graded depression along the south side of 1819 and 1817. The drainage depression is proposed to be approximately 1.5 ft deep and will have a cumulative volume of 1,769 cu-ft. This storage will accommodate the runoff volume of the 2-yr and 10-yr storms, which have estimated runoff volumes of 571 cu-ft and 1,001 cu-ft, respectively. However, the depression will not accommodate the 100-yr storm, which has a runoff volume of 2,143 cu-ft. An 11 ft deep, 2 ft diameter dry well is proposed in the bottom of the depression to allow infiltration and some ponding relief. The dry well will extend 2 ft into the permeable layer. A soils report is attached for reference. When runoff volume exceeds the volume provided within the graded depression, in reference to the provided aerial topography, runoff will pond to an approximate elevation of 5056 ft before draining overland to the east as it has historically. It should be noted that the proposed graded depression and associated ponding volume will reduce the overflow rates and potentially reduce the 100-yr ponding elevation. The proposed dry well will promote infiltration and provide ponding relief. This drainage analysis has been completed to review and mitigate the impacts of the described improvements. Based on this analysis, the proposed improvements do not adversely impact the � 1819 W. Mulberry St 11/4/20 Page 3 of 3 existing drainage conditions and does not increase the volume of ponding and/or runoff rates. The proposed improvements and this analysis do not resolve the current ponding. Regional improvements are necessary to resolve the current ponding and are out of the scope of the proposed improvements and this analysis. The proposed structures at 1819 W. Mulberry Street have been elevated to provide a minimum of one (1) foot of freeboard above the assumed ponding elevation. Though the proposed improvements improve the existing drainage conditions, a 100-yr storm has the potential of inundating structures at 1817 W. Mulberry St. Due to the lack of an adequate outfall, both within the existing and proposed conditions, no guarantee is implied that the structures are protected from a 100-yr rainfall event. Acknowledgement: I acknowledge that the proposed improvements described within and shown on the "1819 W. Mulberry St—Grading & Drainage Plan" are estimated to not increase the existing ponding based on the provided documentation. It is understood that the proposed improvements do not alleviate the current potential of flooding during major rainfall events: 1819 W. Mulberry Street: �^- usq.V� e� e�y(. jt�i�1:A� �rt{.i� Signature �ason Metzler Name 11/5/2020 Date 1�17S1W d�ulberry Street: ,, � y����-� ��,, ^'. v.:: B e,� "�: ^v: f E Signature chapman Rose Name 11/4/2020 Date C���,� � ��1 I��;-z �.,9Ea�.�.,�.� Teresa Metzler 11/5/2020 !M� lM�� M !� � - - _ _ I ' � Qg w.wu�e+urn. I ' 1 � � a ' , - -- _�, � -- -, . . _ _'. , . 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I I� I' �� `i GRADING & DRAINAGE PLAN EXHIBIT A PARCEL DESCRIPTION A iract of land, being part of those parcels as recorded November 23, 2004 as Reception No. 20040] 13985 and December 8, 2019 as Reception No. 20190078982 of the Records of the Larimer County Clerk and Recorder, situate in the Northwest Quarter (NW1/4) of Section Fifteen (I S), Township Seven NoRh (T.7N.), Range Sixty-nine West (R.69W.) of the Sixth Principal Meridian (6th P.M.), Ciry of Fort Collins, Counry of Larimer, State of Colorado and being more particularly described as follows: COMMENCING at the Northwest comer of said Section 15 and assuming the North line of said NW 114 as bearing South 89°26'40" East, being a Grid Bearing of the Colorado State Plane Coordinate System, North Zone, North American Datum 1983(201 l, a distance of2662.02 feet, monumented by a#6 rebar with 2.S' aluminum cap stamped LS 34174 at the Northwest corncr and a#b rebar with 2.5" aluminum cap stamped LS 17497 & 143.7' Witness Comer at the North QuaRer comer of said Section 15 and with all other bearings contained herein relative thereto; THENCE South 89°26'40" East along said North line distance of 1423.50 feet to the common line between said Reception No. 200401 1 3 985 & 20190078982; THENCE South 00°13'ZO" West along said common line distance of 134.89 feet to die POINT OF BEGINNING; THENCE North 89°46'40" West a distance of 3.50 feet to a line parallel with and 3.�0 feet West of, as measured at a right angle, the East line of Reception No. 20190078982; THENCE South 00°i 3'20" West along said pazallel line distance of 49.25 feet; THENCE Nor[h 89°26'40" West a distance of 35.14 feet: THENCE South 00°33'20" West a distance of 31.00 feet; THENCE South 89°26'40" East a distance of 77.99 feer, THENCE North 00°33'20" East a distance of 31.00 feet; THENCE North 89°26'40" West a distance of 32.85 feet to a line parallel with and 6.50 feet East of, as measured et a right angle, the West line of Reception No. 20040113985; THENCE North 00°13'20" East along said parallel line distance of 4931 feet; THENCE North 89°46'40" West a distance of 6.50 feet to the POIN7" OF BEGINNING. Said described parcel of land contains 2,911 Squaze Feet more or less (f). SURVEYORSSTATEMENT I, Steven Pazks, a Colorado Licensed Professional Land Surveyor do hereby state that this Parcel Description was prepared under my personal supervision and checking, and that it is we and correct to the best of my knowledge and belief. Steven Parks - on behalf of Majestic Surveying, LLC Colorado Licensed Professional Land Surveyor 1�38348 _�— � �� MAJESTIC SURVEYING I I I I Diamond Valley Drive. Suiie 104 W'indsoc Colorado ft0550 � ,1 Drninage Easemtnt NW1�4 Sectionl5,T.7N.,R.b9W. NOR'THWE6T CORNER SECTION 15, T.7N., R.69W. FOUND /6 REBAR MATH 2.5' ALUMINUM CAP LS 3�174 POINT OF COMNENCEIAENT � _ _ 142J.50 f919 1BJ7 MULBERRY �'m MULBERRY REC NO. ,�, REC. NO. ?t7190078982 Z(h7f01f39B5 g � N o PO1NT OF N BECINNING N89'46'40"W 3.50'� I S00'13' i 0"W 49.25'� 3.5' N89'26'40"W 35.14'1 S0033'20"W 31.00' � �'�1 `I � DO EXHIBIT A L1'/ESTMULBERRYSTREET (BAS15 QF BEARINCS) S89'26'4D�E 2662.02' 55.00' 60.00' .ID' ROAr 1 P� z orz 143.i H9TNES5 CORNER TO THE NORTN QUAftiER CORNER SECTION )5, T.7N., R.69W. FOl1ND /'6 REBAR WITH� 2.5' ALUNINUM CAP �_ A� _ LS I7497 �I o $ m m N N 3 � � rJ'UB.�E.CT � o PARCEL 8 �2,91 1 SQ. FT. N89'46'40"W 6.50' I N00"13'ZO"E I49.31' 6.5' N89'26'40"W 32.85' I N0033'20"E 31.00' S89'2u'40"E �5.00' S89'26'40'E 60.00� ti�tc. Thi� dro�cing docs nw rcprc�cn! e munumrnted I�id survcy. Ib mic puq,osc u e prnphm rrpicscniatiun ol�hc eccompenying wnucn desaiption. Vuticc Accardmg to Colorndo Isu you must wmmuicc any legel �cuon ba:d upm em ckfm �n thu sunq� within �firce ycus elta ��au fvs� discorer sud� Jc(ett In no evrnt mny eny ucuun based upm� an� de[ect in ihu �urvry bc commmcul more �ha� tcn � rm from thc daic of Nc urnifi�ation slroun hmm� (CRS 13-80.1051 _ _ _ . �:�; � �� .,._ -`- , . --��� -�� � i-, � �r;.,;, � � `.-� ' ' �:� . MA.JESTIC SURVEYING PROIECTNO:'_U19J67 CLIfNT:FORGE+BO�V DATG 10-30-2020 SCALE: I"=3U' �; 383�8 ;o � � /r�'.5n'taZ� �i t�`s�•.. ,,.�a sb,� � �'rAs Stcven Parl:s. PLS 3R348 On bchall'of Mnjesiic Surveying, LLC '�. EXHIBIT A PARCEL DESCRIPTION A[ract of 1and, being part of those parcels as recorded November 23, 2004 as Reception No. 20040113985 and December 8, 2019 as Rcception No. 20190078982 of che Records of the Larimer County Clerk and Recorder, situate in the Northwest Quarter (NW 1/4) of Section Fifteen (15), Township Seven Norih (T.1N.), Range Sixty-nine West (R.69W.) of the Sixth Principal Meridian (6th P.M.), Ciry of Fon Collins, County of Larimer, State of Colorado and being more particulazly described as follows; C0�[MENCING at the Northwest comer of said Section I S and assuming the North line of said NW U4 as bearing South 89°26'40" East, being a Grid Bearing of the Colorado State Plane Coordinate System, North Zone, North American Datum 19832011, a distance of 2662.02 feet, monument� by a#6 rebar with 2.5" aluminum cap stamped LS 34174 at the North�vest comer and a#6 rebar with 2.5" aluminum cap stamped LS 17497 & 143.7' Witness Comer at the North Quarter comer of said Section I S and with all other beazings containod herein relative thereto; THENCE South 89°26'40" East along said North line distance of 1423.50 feet to the common line betwecn said Reception No. 20040113985 & 20190078982; THENCE South 00°13'20" West along said common line distana of 30.00 feet to the South Right of Way (RO� line of Mullxrry 5veet and to the POINT OF BEGINNING; THENCE North 89°26'40" West along said ROW Iine a distance of 6.00 feet to a line parallel with and 6.00 feet West of, as meazured at a right angle, the East line of Reception No. 20190078982; TI-IENCE South 00°13'20" West along said parallel line distance of 104.92 feet; THENCE South 89°46'40" East a distance of 15.00 fcet to a line parallel with and 9.00 feet East of, as measured at a right angle, the West line of Reception No. 200401 ] 3985; THENCE NoRh 00°13'20" East along said parallel line distance of 104.84 feet to said ROW line; THENCE North 89°26'40" West along said ROW line a distance of 9.00 feet to the POINT O� BEGINNING. Said described parcel of land contains 1,573 Square Feet more or less (t). SURVEYORSSTATEMENT I, Steven Parks, a Colorado Licensed Professional Land Surveyor do hereby state that this Parcel Description was prepazed under my personal supervision and checking, and that it is true and correct to the best of my knowledge and belief. Steven Pazks - on behalf of Majestic Surveying, LLC Colorado Licensed Professional Land Surveyor #38348 _� -- — �' l, MAJESTIC SURVEYING I I I I Diamond Valle� Drive. Suitc IOd Windwr, Colorado 80550 Z:�prtyccts�201912019SIP�201936TUL:SC�USAtda Peyc i uf'_ 0 � ;� . Utiliry �. Access Easement NWU4 Section I5, T,7N., R.69W. NORTHWEST CORNER SECTION 15, T.7N., R.69W. FOUND (j6 REBAR WITH 2.5' ALUMINUM CAP LS 34174 POINT OF COMMENCEMENT EXHIBIT A I,#'/ESTMULBERRYSTREET (BASIS Of BEARINGS) S89'26'40"E 2662.02' Page Z o(2 143.7' WITNESS CORNER TO THE NORTH OUARTER CORNER SECTION 15, T.7N., R,69W. FOUND /j6 REBAR INTH 2.5' ALU�IINUM CAP A_ _ LS 17497 l� — t a23.50' — — T I 55.00' � 60, 00' � 0 .JO' RDIY � I o � POINT OF BEGINNING - - - - � - - - N89'26'40"W 9.00' N89'26'40"W 6.00' 9� 0 � 3 0 M $ � I� �� ��pDOI �� 38345 � �: : °� �o-s�-zozv, ss/��'A L LA�� s' �� � /'� �: o 0 � w �� o ° N O N o M o � °° ,� O °° O �v�' p cv � /, Z � ry�� SUBJECT ry � PARCEL � N�1 ,573 SQ. FT. Z � S89'46'40"E 15.00' �a>s MULBERRY REC. NO. 2019007B9B2 589'26'40'E 55.00' �e» MULBERRY REC. NO. ZOG+40113985 589'26'40"E 60.00' Steven Parks, PLti �S3-18 On behalf o(Mujestic Cuncying, L,LC Nutc, lhis dru�� ing ducs nol mprcsent a monumcnlcd lund iunc� � lu sulc pu�wse is y(wphic mprescnmtion of thc accompenying wriuen dacnptlun. Nolitt� Acmrding to Colo2do lew you musl commcncc any legnl aaion baxJ upcm nny Jdctt in ihis sune� wi�hin �hree ytan e(Icr you firstdiuova such de(ect In iw c��em moy any nclion bssed upon eny defeci in U�is swrov be wmmanced mure dmn irn �can from �he dr,te of ihc ccn{fcuiion sho�.n hcrcon. (CRS 13-80.105) �, ��. __ � \, %; j; ,.��—.�._. _ _ _ " j �- �'� � , �i • '1 � ��� ��. ' . �+. MA.JESTIC SURVEYING PRbJL:CI Nt).2019367 CL16\T:FORGE+I30W DATE:10-3U-°0�0 SG\Lt:l"=30'