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HomeMy WebLinkAboutDrainage Reports - 12/07/2001. • ' . , . . ` . . . ' ` ' . • ,. ' . ' '. . , . .. '' . . , � ' • .. :, � � • • � • '� . ' � . • ' . • . . . � . . .. • , - ' . . • ' , • . � ' ''. . - �.. ' • . • . .. . � : • .. ' .`' . : • . .' . � • : , ., : ' _. ••. �. • '� .. ., . . • , . � � • • ' • , ` . • • . , • ' , ; .. . ' : . . . ' . . . . ., . . • ' . . • . . , . . ., . . ' �� � . . � . �1�t�f _�f�� R�p�r+�. . � . . . . . � ' . . , :. . � . . • . • , : , . . -�� : � � . . � �. . . , ��� . a��� �. .v .. �.' . - , . . . : . • . . . . . .. - -. . � � .. . ..,,. ..... .� � �. _ .. . . � �. �:� : � � . : .� . :' -:- .�. � ��' .. . . .... : : .�. . . .� ..:f �. : �- : �. � - . . . .. _ . :� ,. . . . . . _ . .. - . . . .. Collindale. Go{� Course� . �. : . ::.: '� �� _ .. . ; . .. . . � � � � arain�ge RePot� .. .. . � . �, ..- . . . � � . � . . . . : . � � • � . _ . - � � • . • � �• , �,. � . FOf�-. 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Engineers . .. _ , � . � . , 3500 JFIf Parkway . _ � . . � • . �• -. . . . • '. � � . �Staii� �310� . . • - . •' . � � � .. • � . � � �• :Forf�CoHiri's; Colo�ad9:$�525� .� .�• '. . ' . . ,• : . � � - ; - . :;_� � :: . , - � .' ($70) 266-1900 - � �. , • .. . : . . . . . . . � . �on#act: �ed A. Borstad,.P.E: . . . ' ' • . . , . . . • . • : . •. . _.. ", ' . �, a. �Iti"ro�Job .No:.Q1�06$' ' ' .' : • • � . �. � , . . . _ . . • . . , �• � . . • . •.. . , . . . . . � . : .. . .�. ' . . : . .. . . .. : • :: ' : . . . .. _ . : . ' . ' . '' :. . . _ : : ` : : . • . :,. ;,. .. . • .. ' � ' .• . � , . • � � � • .' •..�• � ' -�.. � •• . . • .�'� + . . . . .. _ ; ..1' . '.�_ . .. ., • i• .. , ' . • ' ' • ' , ' '' • . . • '•. • , • ' • . • : . • .. �. . *. - � , , . . ' ��• • • 1 • • � • ' �. • • y . • • ' . ' • • . • . . , • • ' ... + ' , 1, . ' " . . . ' ' •.t �-� • ..•.• •.F.• r�:' � ' . • •� . +, , .. .. . . 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' . . . • . , I ' • ' ♦ � . ♦ . • TABLE OF CONTENTS 1.0 INTRODUCTION .......................................................................................................1 1.1 PURPOSE 1 1.2 SITE LOCATION 1 2.0 DESIGN CRITERIA ..................................................................................................2 2.1 GENERAL 2 2.2 ANALYSIS 2 2.3 DESIGN STORM FREQUENCIES 2 2.4 RLTNOFF COEFFICIENTS 3 2.5 TIlVIE OF CONCENTRATION 3 3.0 DRAINAGE ANALYSIS ............................................................................................ 4 3.1 EXISTING CONDITIONS 4 3.2 PROPOSED CONDITIONS 4 3.2 WATER QUALTTY POND 4 3.3 RETENTION POND 4 3.4 EROSION CONTROL 5 4.0 CONCLUSIONS AND RECOMMENDATIONS ......................................................... 5 5.0 APPENDIX ................................................................................................................ 6 LOCATION MAP 7 HYDROLOGY 8-15 6' CURB CUT CALCULATION 16-17 RAISED CONCRETE HUMP CALCULATIONS 18-20 RETENTION STORAGE CALCULATIONS 21-23 EROSION CONTROL CALCULATIONS 24-25 DRAINGE AND EROSION CONTROL PLAN DRAINAGE BASIN MAP This report for the drainage design of the Collindale Clubhouse was prepared by me (or under my direct supervision) in accordance of the City of Fort Collins Storm Drainage Design Criteria, and was designed to comply with the provisions thereof. "We acknowledge that the City of Fort Collins' review of this study is only for general conformance with submittal requirements, current design criteria and standard engineering principles and practices. 0 Ted A. Borstad, P.E. Collindale Golf Course Drainage Study June 12, 2001 S. A. Miro Proj. No. 01068 Page ii 1.0 INTRODUCTION 1.1 PURPOSE The purpose of this report is to present the drainage characteristics for the proposed reconstruction of the clubhouse and parking lot at the Collindale Golf Course in the City of Fort Collins. 1.2 S/TE LOCAT/ON The proposed construction is located at 1441 East Horsetooth Road along the south side of Horsetooth Road in befinreen Lemay Avenue and Timberline Road. This would place the site in the Northwest quarter of Section 31, Township 7 North, Range 68 West of the 6"' P.M. , City of Fort Collins, Larimer County, Colorado. The Appendix contains a Location Map. Development of the site will entail the demolition of the existing clubhouse and parking lot and the constructing of a new clubhouse and parking lot. Collindale Golf Course Drainage Study June 12, 2001 S. A. Miro Proj. No. 01068 Page 1 � � ' 2.0 DESIGN CRITERIA 2.1 GENERAL '' The procedures, criteria and standards for stormwater management in this design comply with the reference manual "City of Fort Collins Storm Drainage Design Criteria and Construction Standards" and also "Urban Storm Drainage Criteria Manual" volumes 2 and 3. Technical data as it applies to this analysis is included in the Appendix. i �w , 2.2 ANAL YSIS Since the study area is less than 200 acres, an analysis and determination of the ' amount of flows� at various predetermined points has been made� using the "Rational Method." The runoff analysis is based on the proposed land use and topographic features of the project area. � The average land stopes are used for computing runoff. I� 2.3 DESIGN STORM FREQUENCIES The initial and major design storm runoff drainage has been analyzed in this report. The initial design storm drainage system, based on a 10-year storm frequency, is designed to provide protection against regularly recurring damage, provide an orderly drainage system and offer convenience to the general public. The storm sewer system and is considered to be part of the initial storm drainage system. The major design storm drainage system, based on a 100-year storm frequency, is that system which will convey the major storm runoff that will cause little or no major property damage or loss of life. Collindale Golf Course Drainage Study June 12, 2001 S. A. Miro Proj. No. 01068 Page 2 ' � ' ' IC I� �� � 2.4 RUNOFF COEFFICIENTS The runoff coefficient, C, used in conjunction with the Rational Method, is listed in the Appendix, and was obtained from Table 3-3 of the "City of Fort Collins Storm Drainage Design Criteria and Construction Standards." The Rational Method Formula used in this report is: Q=CCfIA Where � I A C Cf = Storm Flow, CFS - Rainfall Intensity (iNhr) = Drainage Area (Acres) = Runoff Coefficient = Frequency Adjustment Factor ' 2.5 T1ME OF CONCENTRATlON The time of concentration (when maximum discharge of the drainage area is reached) is F the time required for runoff from the most remote point of the drainage area to arrive at y� the design point. The "most remote point" is that point from which the time of flow to the design point is the greatest and not necessarily the greatest linear distance. ' �' � �, ' 1 ' �' �� 1 � 3 3.0 DRAINAGE ANALYSIS 3.1 EX/ST/NG COND/T/ONS The site currently is an active golf course with a clubhouse along with an associated parking lot. Slopes in the parking lot vary between 0.50% and 2.00%. The general drainage pattern flows eastward to a curb cut in the parking lot and. The existing 10- year flow at this point is 5.41 cfs and the 100-year flow is 13.80 cfs. Storm water then proceeds to flow easterly to the Union Pacific Rail line at a peak value of 7.03 cfs in the 10-year event and 17.91 cfs in the 100-year event. 3.2 PROPOSED COND/T/ONS The proposed construction increases the impervious coverage by approximately 0.13 acres more than existing. This results in an increase in the parking lot area of 1.56 cfs during the 10-year storm and 4.00 cfs during the 100-year storm. A raised concrete hump is located along the driveway in front of the proposed clubhouse. During the 10- year storm, 5.2 cfs will flow around the hump along the gutter. Calculations using Land Development DesktopT"" channel calculator program shows that the gutter along the hump has capacity for 6.11 cfs before overtopping. During the 100-year storm, 13.1 cfs will overtop the raised concrete approximately 3.5 inches to an elevation of 4971.5 which is 5.5 feet below the first floor. Runoff from the 2.2 acre parking lot drainage area will discharge through a proposed 6' curb cut at 6.97 cfs in the 10-year storm to the same general area it does under existing conditions. The water then flows approximately 1,800 feet eastward over lawn area to the railroad at shallow slopes. The drainage area to the railroad is 22.5 acres and peaks at a 41.9 cfs rate during the 100- year storm. 3.3 RETENT/ON POND There is no proposed detention system designed for the site. As mentioned above, the runoff will flow eastward to the railroad. Lowpoints in this area will provide retention for any storm water reaching this point which does not infiltrate into the ground beforehand. A mass balance detention sizing analysis was performed for this study. Using a conservative historical rate, assuming the entire drainage area is undeveloped with no impervious coverage or ponding, determines that a detention volume of 1.5 acre-feet is necessary. The amount of retention needed is equal to twice the detention volume, or 3 acre-feet. Using Land Development DesktopT"" terrain modeling software, a retention volume of 4.4 acre-feet exists near the railroad which will satisfy requirements. Since retention is taking place and there is 1800 feet of sheet flow in the golf course grass, no additional means of water quality is proposed. Collindale Golf Course Drainage Study June 12, 2001 S. A. Miro Proj. No. 01068 Page 4 ' I� 3.4 EROS/ON CONTROL � During construction the majority of the developed site area will be sloped towards the east at slopes in the range of 1% to 2%. Staked hay bales will be placed in the , � proposed trickle pan area in the parking lot to trap sediment before entering the lawn area. Silt fence surrounding downslope area of the proposed construction will trap additional sediment. Grading will be mulched within 30 days of reaching finished grade. � After construction, a proposed pad of modular block porous pavement downstream of the proposed 6' curb cut will provide some settlement of particles and provide an easier means of cleaning trash and sediment from the lawn area. These erosion control � measures will minimize erosion and sedimentation damages during and after the period of construction for the proposed Collindale Golf Course clubhouse and parking lot. 4.0 CONCLUSIONS AND RECOMMENDATIONS � As it exists today, the golf course's natural terrain provides a means for controlling � storm runoff. Horsetooth Road, which borders the course, sits higher than the golf � course as does the Union Pacific Railroad at the downstream end of the drainage area creating a natural depression storage volume. No signs of erosion exists that would � show excessive velocities are present and an additional 0.13 acres of impervious coverage will not adversely affect current conditions. The construction to take place will provide means of erosion control. In conclusion, the proposed Collindale Golf Course � site will have drainage characteristics closely resembling existing conditions that already are reasonable. ,� � � � � � L ' Collindale Golf Course Drainage Study June 12, 2001 S. A. Miro Proj. No. 01068 Page 5 � . ' � r � 5.0 APPENDIX , � � � � ' , 1 ' 1 1 �� ' ,. ■ Collindale Golf Course Drainage Study S. A. Miro Proj. No. 01068 June 12, 2001 Page 6 VICINITY MAP N TS % DRAtNAGE CRiTERIA NIQINUAL I�u�vvrr 50 30 F- 2 0 z W c.i � W a 10 z W a � 5 N w y 3 � � O C) 2 cc W F- a 3 � � .2 .3 .5 1 2 3 5 VELOCITY IN FEET PER SECOND �0 20 FtGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCiTY FOR USE WITH THE RATIONAL FORMULA. f MOST FREOUENTLY OCCURRING "UNDEVELOPED" LAND SURFACES IN THE DENVER REGiON. REFERENCE: "U�ban Hydrology For Small Wate�aheds" Technical Retease No. 55, USDA, SCS Jan. 1975. . 5 -1-84 URBAN DRAINAGE d� FLO00 CONTROL DISTRICT i City of Fort Co!lins Rainfall Intensity-Duratlon-Frequency Table for using the Rational Method (5 minutes - 30 minutes) Fgure 3•1 a Duration 2-year 10-year 100-year (minutes) Intensity Intensity Intensity in/F�r in/hr in/hr 5.00 2.85 4.87 9.95 6.00 2.67 4.56 9.31 7.00 2.52 4.31 8.80 8.00 2.40 4.10 8.38 9.00 2.30 3.93 8.03 10.00 2.21 3.78 7.72 11.00 2.13 3.63 7.42 12.00 2.05 3.50 7.16 13.00 1.98 3.39 6.92 14.00 1.92 3.29 6.71 15.00 1.87 3.19 6.52 16.00 1.81 3.08 6.30 17.00 1.75 2.99 6.10 18.00 1.70 2.90 5.92 19.00 1.65 2.82 5.75 20.00 1.61 2.74 5.60 21.00 1.5fi 2.67 5.46 22.00 1.53 2.61 5.32 23.00 1.49 2.55 . 5.20 24.00 1.46 2.49 5.09 25.00 1.43 2.44 4.98 26.00 1.40 2.39 4.87 27.00 1.37 2.34 4.78 28.00 1.34 2.29 4.69 29.00 1.32 2.25 4.60 30.00 1.30 2.21 4.52 0 � , ' �� ' City of Fort Collins Rainfali Intensity-Duration-Frequency Table for using the Rational Method (5 minutes - 30 minutes) Figure 3-1 a Duration 2-year 10-year 100-year (minutes) lntensity Intensity Intensity in/hr in/hr in/hr 5.00 2.85 4.87 9.95 6.00 2.fi7 4.56 9.31 7.00 2.52 4.31 8.80 5.00 2.40 4.10 8.38 9.00 2.30 3.93 8.03 10.00 2.21 3.78 7.72 11.00 2.13 3.63 7.42 12.00 2.05 3.50 7.16 13.00 1.98 3.39 6.92 14.00 1.92 3.29 6.71 15.00 1.87 3.19 6.52 16.00 1.81 3.08 6.30 17.00 1.75 2.99 6.10 18.00 1.70 2.90 5.92 19.00 1.65 2.82 5.75 20.00 1.61 2.74 5.60 21.00 1.56 2.67 5.46 22.00 1.53 2.61 5.32 23.00 1.49 2.55 . 5.20 24.00 1.46 2.49 5.09 25.00 1.43 2.44 4.98 26.00 1.40 2.39 4.87 27.00 1.37 2.34 4.78 28.00 1.34 2.29 4.69 29.00 1.32 2.25 4.60 30.00 1.30 2.21 4.52 � � COMPOSITE C CALCULATION , COLLINDALE GOLF COURSE CALCULATED BY BEC DATE 610/01 ' Native Grassed Area C= 0.20 ' Paved Area C= 0.95 ' Ponds C= 0.95 � DESIGN BASIN �pppgg �+ppVEDAREAS �a �4or,i COMPOSITE POINT DESIG Acre Acre Acre (Ac C�o C,� DP#1 PROPOSED 0.20 1.12 0.00 1.32 0.84 1.00 DP#2 PROPOSED 0.45 1.74 0.00 2.19 0.80 0.99 DP#2 EXISTING 0.58 1.61 0.00 2.19 0.75 0.94 DP#3 PROPOSED 15.79 1.74 4.93 22.46 0.42 0.53 DP#3 HISTORIC 22.46 0.00 0.00 22.46 0.20 0.25 � ' r � U � ' U ,- � � � T � � , y Y II � � o a t �' w a� � J Q ' O a«}� N O� r N N Z � LL o� �'n�°�av 0 � ' w r � � o 0 0�� Z N O N Q � � c O W w' L � � � Q U o Z� O � WC � G � UI W m } m 0 w g � J a U �y- � T o� c� rn . . 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N W tD �` N p a v� c� .- o CO cc j U a � cV c�i ; ui � F- U w c ��oc`to`nw � �� � u-> a� � rS o 0 �v�n C d � � � � U N ¢ V .--0000 W t> N ���vv Qa .-N NN N ww�7w�V Z ��Zt!)� � �oo�oo aa�na� w OOXOcn o aaw�= m � � VC N C�t M M w , � � � � � _ o � d a a a o a oonoo � 1S ! � 6' CURB CUT � The proposed 6' curb cut is located at the eastern most corner of the parking lot. A weir calculation using Land Development DesktopT"' shows that the 10-year flow of 6.97 cfs will cause the water to rise to 5.8 inches in the parking lot. The 100 year flow of 17.80 � cfs will overtop the curb and continue flowing eastward toward the Union Pacific Railroad. i 1 1 1 1 1 1 � 1 1 1 1 1 � � 16 tmp#l.txt 6' Curb Cut Calculator Given Input Data: Weir Type ....................... Rectangular Equation ........................ Suppressed Solving for ..................... Depth of Flow Flowrate ........................ 6.9700 cfs Coefficient ..................... 0.6500 Height .......................... 6.0000 in Computed Results: Depth of Flow ................... 5.7789 in Full Flow ....................... 7.3739 cfs Velocity ........................ 2.4122 fps Width ................�........... 72.0000 in Area ............................ 3.0000 ft2 Perimeter ....................... 84.0000 in Wet Perimeter ................... 83.5577 in Wet Area ........................ 2.8894 ft2 Percent Full .................... 96.3144 � Page 1 � � ' RAISED CONCRETE HUMP A proposed concrete hump is located at the front entrance to the clubhouse. It will stretch out over the driveway at a 6 inch height. Runoff will pass through this hump along the southern gutterline where there will be a 2 foot wide opening in between the curb and the hump. Land Development DesktopT"" channel calculations show that this opening can discharge 6.11 cfs before overtopping the 6 inch high raised concrete, meaning that the 10-year event of 5.17 cfs will not overtop the raised concrete. During the 100- year event of 12.63 cfs, there will be approximately 6.52 cfs spilling over the concrete hump and 6.11 cfs flowing around the hump in the gutter. This equates to an approximate 3.3 inch depth (elevation 4971.5) of flow over the hump which is 5.5 feet below the first floor. Collindale Golf Course June 12, 2001 S. A. Miro Proj. No. 01068 �g tmp#l.txt Raised Concrete Gutter Flow Capacity Given Input Data: Shape ........................... Rectangular Solving for ..................... Flowrate Slope ........................... 0.0124 ft/ft Manning's n ..................... 0.0130 Depth ........................... 6.0000 in Height .......................... 6.0000 in Bottom width .................... 24.0000 in Computed Results: Flowrate ........................ 6.1194 cfs Ve�locity ........................ 6.1194 fps Flow area ....................... 1.0000 ft2 Flow perimeter .................. 36.0000 in Hydraulic radius ................ 4.0000 in Top width ....................... 24.0000 in Area ............................ 1.0000 ft2 Perimeter ....................... 36.0000 in Percent full .................... 100.0000 � Page 1 � �9 � , , r , � � 1 � ' ' �� ' ' , ' � ' ' , ' tmp#1.txt Raised Concrete Hump- 100-year Given Input Data: Shape ........................... Trapezoidal Solving for ..................... Depth of Flow Flowrate ........................ 6.5200 cfs Slope ........................... 0.0124 ft/ft Manning's n ..................... 0.0130 Height .......................... 6.0000 in Bottom width .................... 1.0000 in Left slope ...................... 50.0000 ft/ft Right slope ..................... 0.0000 ft/ft Computed Results: Depth ........................... 3.3175 in Velocity ........................ 3.3716 fps Flow area ....................... 1.9338 ft2 Flow perimeter .................. 170.2281 in Hydraulic radius ................ 1.6359 in Top width ....................... 166.8774 in Area ............................ 6.2917 ft2 Perimeter ....................... 307.0600 in Percent full .................... 55.2925 � Flow over hump= (100-year flow) -(gutter capacity)= 12.63-6.11= 6. 52 cfs Page 1 20 1 ' RETENTION STORAGE ' Due to the existing contour of the land near the northeast corner of the Collindale Golf Course being at a higher elevation than the course itself, there is existing retention taking place. The Union Pacific Railroad has tracks at elevation 4956 and Horsetooth , road has a lowpoint at an elevation of 4955 at this area. Using Land Development DesktopT"" to calculate a volume of depression storage in this vicinity shows that there is approximately 4.4 acre-feet of storage available below elevation 4955. A mass , balance calculation was performed where the detention needed is calculated by subtracting the cumulative ouiflow volume from the inflow volume at sequential time intervals. In this case the ouflow rate is taken to be the historical flow to the northeast ' corner of the golf course. Instead of computing the historical rate based on an existing runoff coefficient including the existing impervious coverage, the historical rate is based on the drainage area consisting entirely of grass. Using these numbers, a detention , volume of 1.5 acre-feet is required for this drainage basin. Since there is. no outlet for the runoff to flow past the railroad, retention must be used instead of detention. This means that finrice the amount of detention storage, or 3 acre-feet, is necessary. There is ' 4.4 acre-feet available which is more than required and thus no additional means of volume control is necessary. ' � �� 1 I' ' , �' Collindale Golf Course June 12, 2001 S. A. Miro Proj. No. 01068 ' �—' ' ' � Oc'� ���0� �O�CO ''� � a0 v' cD 00 O�— N O r I� e� Q� ,�„ CD O: I� T�Ci I� �Ci T Cp O f� L= �y, N Ch ��A lA 1A t[) ln r O� �3 �'v 0 0 0 0 0 0 0 0 0 0 0 aaQ � roc�cflrnrnc�►r�aocv �� � u") 1� M �A N CD C7 e7 N I� i C N(D �A O O r N � C'9 M� ,� 1� f� � 00 00 1� CO C7 00 N �7 � v c0 � 1� �i O� 00 O N GO c�7 O� a a r r N N N N N N^ N � � � d� O O O O O O O O O O O C� � i� `'' � 00 f� CD ln � r CO N CD et '� l0 C! O r N C'O � ln CO O CO r N �'- Z�_ r. 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T r r T T �I, � �� C � Q � � 0 � � � 0 � � . O � � � � 0 0 � � � � 0 M(O�Ntf)COf�-CO�N00 _ �� T T T N C�i tfJ I� O O> > � T ._ o +� � ^ vo�caaoTrnv�vr� L� �� CO (D N OD �- O 00 N c0 � �` ,�% 00 T I� C� O% C'7 T� M O CO � O� � O> f� CO t1') tf3 'a' C7 N N r Q T t� Q � � VJ W � � W � � � � � . � M � � � � � � � � � � � m � N N N N N N N N N N N � v Q v �NN�OONCC(DO00 -' �' �- � I� u") CO � t1� �Y 00 O I� � r�-. N Q� I� CD ��� C') N N r r C � � � C �- � C7 (''� C'� M M C7 M C7 M C*� M � � � � � � � � � � � � � O O O O O O O O O O O � c.i �O�NNcc�� C�O�N0�0 Qi �1 T T � � �. 3 , - � PERFORMANCE STANDARDS TOTAL 2.14 PS DURING CONSTRUCTION- PSAFfER CONSTRUCTION- 78.70 92.59 740.00 1.22 78.70 Z- �'� 1 .� . . ' EFFECTIVENESS DURING CONSTRUCTION ' BASIN EROSION CONTROL C-FACTOR P-FACTOR AREA EFFECTIVENESS ' METHOD ACRE A GRAVEL MULCH 0.05 1 1.74 95 NET NET EFFECTIVENESS: PS DURING CONSTRUCTION: 94.79 84.1 2.19 94.79 EFFECTIVENESS AFrER CONSTRUCTION N ET NET EFFECTIVENESS: PS AFTER CONSTRUCTION: 99.00 92.59 2.19 99.00 ZS iiiii\ /iiiii ii�ii\\ //uu• \\\ ///u�v :::::`�`\ //�%iiiii 111\\/// /.. u���\\;`����%%iiiii iiiii\\\\`� ///uu• u�u1\\\\%%///uu• •���u\\\1///Li����• iiiiiii:�\//i:i:ii:i •uuu����iu�vv uu������iu���u�� nni�o �� • .• .� .- . . :. � •�� . �� -� '� _ _ .�-� __ -� __� �- ti �"j .. � __ _.___ '_ -' �� �'�� - .o� � _.___ —._�_ ` �``�+.. --_"' �.�._ ,�/� .. .�m. �..,_.» .7m._, _�e .� � = � � � � — — — — —{— ' I � g� :� e,r� R......� s� J �'�` l `.,`e I `� f '` - ``v ; �' �r , , f J� ! �� 1 / I I �'�° 2' CURB CUT _. � �� v�� �..��,�� �,� � — — �, t � � /. �/ - � � '� ��--� .r . ! �� �'� — _ �6A�_ _ _ — � 3' PROPOSED GRAVE� CHEC�#t bAM (TYP.) ! �� .�'� /Y4Las•�A a�A�A� �� $i",...y , x A �� � �� z � —�—� o� � � � �, saF��- � ;� ,o : �� i� ,ew , `�ga` � r zy o a � .. ' vY.' Sr�. � � . a���� ' �' � a� � < z � �n �• v 1: � `��`' � CHECK DAM (TYP.) � �6�/ r ;' . � � _ ��'� `� _ i" _ ���` DP #1 Q,o =5.17cfs Q„� =12.63cfs � ■ I�I HORSETOOTH ROAD �� � `� � - � � - � � -.�'� �....-'_..�......� - � � � �.� .�._�. � � - � � �.....� ��::-- � ....�� — — .— ��+ — — — — — — —�a�i�3 — . — — — — .— — — — �G'�— — — — —t�.^_ 3— ,1 \�� � /' '= �� 1 l�I � \ / �' 2' CURB CUT i i i i�.i i' i� i i n/ � �PROPOSED GRAVEL 3' PAN � CHECK DAM (TYP.) � 2� CURB � . CUT r � ��I' 1 � . . �,��' . . . . ... � �.y. . � �._ � -_._ l , — — — — -...__ --_ _�,. „` �- _ ,` i` i � � ,' r` � � � 1' �ry, T�\ � -.,, ` ` __ ; _� �\ . \ � ,� i �, � f ___ > � > `_. - DESIGN AREA INITIAL STORM INITIAL STORM 10 YEAR 100 YEAR POINT (ACRE) COEFFICIENT TIME OF CONCENTRATION FLOW FLOW ("C") (MIN.) (CFS) (CFS) 1 1.32 .84 5.69 5.17 12.63 2 2.19 .80 8.63 6.97 17.80 I I I `,I 2' CURB OPENING PROPOSED GRAVEL ! f . �. i � __ ' �, ,� ' - �� . � n I �_» �o �. . ��— , � �.... . . - . . . . . -E� . . . . .. . ' r, t � I � r r � jf r` � !'" `� �� �� ~ �,,, f � � '. ..., .. , \ � ti ; „ �''\ � ,, .- � �.., �. �. � : � �� ? ' ' \ g � ' / / / DP Q�o =6.9' ( ,. _ .,.. _. �. I 6' CURB a i ��T Q,�=17.8Qcfs °' � � / � � � (,_ � . / w `�. � ' PROPOSED 835 LF � '� SILT FENCE t, (TYP) ,'�_ � \ ��° � i \ � � � � ! � ��, � � � �— f� \ � j �t � NOTE: SEE SHEET C10 FOR DRAINAGE AND EROSION CONTROL NOTES AND DETAILS. � �� PROPOSED STRAW — BALE BARRIER (TYP.) PROPOSED 8'L x 6'W MODULAR BLOCK POROUS PAVEMENT � 0.50% ; ,�. ,r a �,-- , ��- CALL UTILITY NOTIFICATION CENTER OF COLORADO 1-800-922-1987 CALL 2—BUS�NESS DAYS IN ADVANCE BEFORE YOU DIG, GRADE, OR DCCAVATE FOR THE MARKING OF UNDERGROUND MEMBER UTILITIES. 30 0 30 60 SCALE: 1" = 30' 1'� • • � � „'t"'� �= � j � U � (=j � U Q W p O l�L J � p w � W Z J a > z a Z U 0 W W � � � Z F Q Z 1— C7 � U Z Z � � W O Q J � � c� a o DESIGNED BY: BEC DRAWN BY: CLS CHECKED BY: TGE City of Fort Cotlins, Colorado FILE NAME: P—DRAIN UTILITY PLAN APPROVAL DATE: AUG/07/01 APPROVED: City Engineer Date MIRO JOB CLIENT JOB CHECKED BY: NUMBER NUMBER Water 8c Wastewater Util(ty Date 01068 ----- CHECKED BY: Stormwater Utlity Date �^\ CHECKED BY: ( -� Parks dc Recreotion Dote v CHECKED BY: Trafflc Engineer Date cHECKEo aY: SHEET N0. 10 OF 12 n...e ..... �::::�� ii::::: ....��� iii..... CC:C:C��� ii�i::::: ..����iiii�..... •u��\1\\\//// ����• iiiii\\\\`��%%%ii�ii uu��\\\\//%�/,ui�• iiiiiii�\1///iiiiiu u\\%%uu� �� iiiiiiu���uuuiu uu�uu. uuuu• 9' •• '• � � �. ^'��iWlWl�w� :esrr����r�r���r���������� t�. rf� � U�p � 1.32 A Y. 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DP#2 ,. � � _. ___� � ;� .� _ , � d _ �'§ � � _; .: '� ti . �� , - � °� r: �.. �•�� J \ , , ��{i � ' ' -,,.. , � �,—DRAINAGE� z � BASIN BOUNDARY (TYP.) ; 20.27 ACRES � � PROPOSED DRAINAGE CONDITIONS DESIGN AREA INITIAL STORM INITIAL STORM 10 YEAR 100 YEAR POINT (ACRE) COEFFICIENT TIME OF CONCENTRATION FLOW FLOW ("C") (MIN.) (CFS) (CFS) 1 1.32 .84 5.69 5.17 12.63 2 2.19 .80 8.63 6.97 17.80 3 22.46 .42 43.64 16.41 41.89 HISTORIC DRAINAGE CONDITIONS DESIGN AREA INITIAL STORM INITIAL STORM 10 YEAR 100 YEAR POINT (ACRE) COEFFICIENT TIME OF CONCENTRATION FLOW FLOW ("C") (MIN.) (CFS) (CFS) 3 22.46 .2 50.85 7.03 17.91 S.A. MIRO INC. CONSULTING ENGINEERS 3500 JFK PARKWAY, SUITE 310 FORT COLLINS, CO 80525 (970) 266-1900 (970) 266-0276 FAX WWW.SAMIRO.COM : . . � . ,11"11� � � � � � J U Q w � � � z a o a U 0° w LL � � � w � � Q � > Z J � w w '�' a � � Z F— Q Z f— � r w Z w O Q U d 0 DESIGNED 8Y: BEC DRAWN BY: CLS CHECKED BY: TGE FILE NAME: P—DRAIN DATE: AUG/07/O1 MIRO JOB CLIENT JOB NUMBER NUMBER 01068 ----- 60 0 60 120 SCALE: 1" = 60' SHEET N0. `"_""r „�