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HomeMy WebLinkAboutDrainage Reports - 12/06/2005I I 1 1 1 11 1 I FinWApdperIZ16�oS FINAL DRAINAGE AND EROSION CONTROL REPORT FOR SONIC DRIVE-IN - LOT 4 TOWER SHOPPES P.U.D. / ADDENDUM TO THE FINAL DRAINAGE AND EROSION CONTROL STUDY TOWER SHOPPES P.U.D. Prepared for: The W.W. Reynolds Companies 1600 Specht Point Drive, Suite C Fort Collins, CO 80525 Ph. 970.482.4800 Fax 970.686.5011 Prepared by: Interwest Consulting Group 1218 W. Ash, Suite C Windsor, Colorado 80550 Ph. 970.674.3300 Fax 970.674.3303 June 29, 2005 Revised October 5, 2005 Revised November 16, 2005 1 INTERWEST M CONSULTING GROUP I I 1 November 16, 2005 Mr. Basil Hamdan ' City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, CO 80521 ' RE: Final Drainage and Erosion Control Report for Sonic Drive -In — Lot 4 Tower Shoppes P.U.D. / Addendum to the Final Drainage and Erosion Control Study Tower Shoppes P.U.D. Dear Basil: ' We are pleased to submit for your review this revised Addendum to the Final Drainage and Erosion Control Study for the Tower Shoppes P.U.D. This report describes and details the proposed water quality facility that is required under the current City of Fort Collins Storm Drainage Criteria for the ' development of Lots 1, 2, and 4 to occur. This Addendum also serves as the Final Drainage and Erosion Control Report for Sonic Drive -In located on Lot 4 Tower Shoppes P.U.D. All computations within this report have been completed in compliance with the City of Fort Collins Storm Drainage Design Criteria and the "Urban Storm Drainage Criteria Manual" (UDFCD) Volume 3. ' We greatly appreciate your time and consideration in reviewing this submittal. Please call if you have any questions. Sincerely, QPO� REPI�T�9F� I ' VVLV14l1V 1 fV1VJJ1VllLLl /YO �•.•..•.��� Engineer No. 34767 FFSSIm� M [1 J TABLE OF CONTENTS PAGE TABLE OF CONTENTS 1i 1. INTRODUCTION..................................................................................................................1 ' 2. PROJECT BACKGROUND.................................................................................................1 3. ............................ DETENTION REQUIREMENTS..:: ..2 3.1 Site Description ...................... ............................ ....... ................... 3.2 Regional Pond Description.............................................................................................3 3.3 On -site Detention Calculations.......................................................................................3 4. WATER QUALITY REQUIREMENTS..............................................................................4 1 4.1 Site Description...............................................................................................................4 4.2 Extended Detention Basin Design..................................................................................5 4.3 Outlet Structure Design...................................................................................................5 ' 5. EROSION AND SEDIMENT CONTROL...........................................................................6 5.1 Erosion and Sediment Control Measures........................................................................6 5.2 Dust Abatement... ............................................................................................................ 7 5.3 Tracking Mud on City Streets.........................................................................................7 5.4 Maintenance....................................................................................................................7 5.5 Permanent Stabilization..................................................................................................8 6. VARIENCES...........................................................................................................................8 ' 6. CONCLUSIONS.....................................................................................................................8 ' 7. REFERENCES.......................................................................................................................9 Appendix A: Detention Calculations Appendix B: Extended Detention Basin Design Appendix C: Excerpts from other Reports ' Appendix D: Erosion Control Calculations I I n I 1. INTRODUCTION tThis report is an addendum to the Final Drainage and Erosion Control Study for the Tower Shoppes P.U.D. (RBD, Inc., 1995) and provides details of the proposed extended detention basin (EDB) sedimentation facility for Lots 1, 2 and 4 of the Tower Shoppes P.U.D. The Tower Shoppes P.U.D. is located in the northeast comer of the intersection of Horsetooth Road and Timberline Road in the City of Fort Collins, Colorado. Lots 1, 2 and 4 of the Tower Shoppes P.U.D., hereafter referred to as "site", are currently undeveloped land. The ' New Fort Collins High School lies on the north and east sides of the site and a McDonalds Restaurant occupies Lot 3. Construction plans for a Sonic Drive -In Restaurant on Lot 4 are currently undergoing development review and are being submitted in conjunction with this Drainage Report Addendum. I I J I sNorwood) s._.. ' 1 ` � 4 URodM L�b god Dr i' 5 a Utt1s - Or n 1b ' � Willow Waterford Ln_ OR Collindale Or c C ar 1 i QuaB Hollow Dr 4 - �Q 9 _. Preston Tri '^ pike Cy N ° •$_--- - I Pike Clr S' ---- -E Horsetooth Rd a I—X*:_,. _ r, },,a rt+er 'ra " 'fk'>� - 44 I� �_ I . Bighorn Ftd �_KodARa N WQlau- y 'yy 7 �,�, � .'>�'• x a r.r' �r•A� a o �_; � '� f - Arctic Fox Or, "'Disim Rd_ - C°Jlindwi¢ a 'GoijCouraa ii' �' �ti i "1. m r r + �SrinbrCst _-- V DC i r we I °r+e Cr AstoPad S __ __. ••r i Caribou Or Figure 1— Vicinity Map 2. PROJECT BACKGROUND The Final Drainage and Erosion Control Study for the Tower Shoppes P.U.D. was approved on June 7, 1995. Since the time that this drainage study was completed, the City of Fort Collins (CFC) has modified their stormwater design criteria to include stormwater quality enhancement requirements and the use of a larger design storm based on a 1998 precipitation 1] Addendum to the Final Drainage and Erosion Control Study Page 1 Tower Shoppes P.U.D. November 16, 2005 L study. Because more than three years has elapsed from the time of plan approvals, the undeveloped Lots 1, 2 and 4 of the Tower Shoppes P.U.D. are now required to meet the updated design criteria. On March 31, 2005 representatives from the CFC Stormwater Utility, CFC Attorney's office, WW Reynolds (property owner), Sonic (prospective purchaser), and Interwest Consulting Group met to discuss what would now be required for Lots 1, 2 and 4 to be developed. It was agreed that detention should be provided for the undeveloped portions of Lot 2 and Lot 4 and that water quality enhancements should be provided for the undeveloped portions of Lot 2, Lot 4 and the west half (parking area) of Lot 1. The required detention volume is based on the difference between the old design storm (2.89" over 2 hrs) and the current design storm (3.67" over 2 hrs) for fully developed conditions. The water quality enhancement method that was recommended by the CFC is an extended detention basin with a 40-hr drain time. 1 3. DETENTION REQUIREMENTS 1 3.1 Site Description 1 The portion of the site for which additional detention is required includes the undeveloped portions of Lot 2 (Basin A, 0.78 acres) and Lot 4 (Basin C, 0.76 acres) for a total of 1.54 acres of commercial property. Historically the site drains to the northeast to the New Fort Collins High School stormwater conveyance system via two temporary swales that were constructed with the McDonalds Restaurant on Lot 3 per the Addendum to the Final Drainage and Erosion Control Report for the Tower Shoppes, P.U.D, Lot 3 (RBD, 1995). I Detention for the site in fully developed conditions was accounted for in the regional detention pond located along the eastern side of the New Fort Collins High School property (Meline & Irelan,1993). This regional pond is known as Detention Pond 213 in the SWMM model for the High School site and in the S WMM model for the entire Foothills Basin. The proposed percent imperviousness for the Tower Shoppes P.U.D. (71-79%) is equal to or less than the assumed percent imperviousness used to design the regional pond (85-89%). The proposed percent imperviousness for the new Sonic Drive -In on Lot 4 is 80% and the ' remaining undeveloped lots are expected to have a percent imperviousness that meets or is less than the designed values. 1 Addendum to the Final Drainage and Erosion Control Study Page 2 Tower Shoppes P.U.D. November 16, 2005 I I I Figure 2 — Existing temporary swale from west side of the site 3.2 Regional Pond Description The regional detention pond on the eastern side of the New Fort Collins High School site, Pond 213, was originally designed with 7.8 ac-ft of storage and 0.6-ft of freeboard during a 100-year storm under the old rainfall conditions. A variance for less than 1-foot of freeboard was requested and granted with the New Fort Collins High School site. In 1995 an overtopping analysis of this pond was completed by Lidstone & Anderson and a revised storage -discharge rating curve was incorporated into the Foothills Basin SWMM model. The overtopping analysis assumed that the outlet was completely plugged and indicated that Pond 213 begins to overtop when it reaches a storage volume of 11.77 ac-ft. The most current SWMM model for the Foothills basin that includes the updated rainfall data shows that Pond 213 reaches a peak discharge of 44.2 cfs at a storage volume of 11.40 ac-ft during a 100-year event. Thus, the regional detention pond has 0.37 ac-ft of extra storage capacity before the pond begins to overtop during a 100-year storm event (11.77 — ' 11.40 ac-ft). ' 3.3 On -site Detention Calculations The area for which additional detention is being required is less than 5-acres and therefore the Rational Volumetric FAA Method was used to calculate the required detention volume r(directed by Basil Harridan, CFC Stormwater Utility). The total tributary area is 1.54-acres 1 Addendum to the Final Drainage and Erosion Control Study Page 3 Tower Shoppes P.U.D. November 16, 2005 (Lots 2 & 4) and a minor storm "C" coefficient of 0.74 (equal to that used in the Tower Shoppes Drainage Report) and a major "C" coefficient of 0.93 was used for the 100-year storm. The allowable release rate was set to 12.0 cfs which is equal to the developed ' undetained peak flow rate from this area under the old rainfall standards. The input storm is the 100-year storm using the new rainfall standards and the resulting detention volume requirement is 0.03 ac-ft ' The excess storage capacity of the regional detention Pond 213 is 0.37 ac-ft and the required storage volume for the difference in rainfall standards for Lots 2 & 4 is 0.03 ac-ft. In the worse case scenario where the peak detention requirements for Pond 213 and Lots 2 & 4 occurred simultaneously then the impact to the regional pond is still negligible. The peak discharge rate would remain the same at 44.2 cfs with no change in the water surface elevation. Thus detention for Lots 2 & 4 will be provided in the regional pond and on -site detention for Lots 2 & 4 will not be required. This conclusion was discussed and agreed ' upon with Basil Hamdan during a phone conversation in early April, 2005 I4. WATER QUALITY REQUIREMENTS ' 4.1 Site Description The portion of the site for which water quality enhancements is required includes Lot 2 (Basin A), Lot 4 (Basin C) and the west half of Lot 1 (Basin B) for a total of 4.33-acres (0.78 + 0.76 + 2.79 acres) of commercial property. The west half of Lot 1 contains a future ' parking lot and the east half of Lot 1 is the location of a future building. Only the west half of Lot 1 is being included in the water quality area because parking areas will generate more pollutants which should be removed. Currently the site drains to the northeast to the New Fort Collins High School stormwater conveyance system via two temporary swales that were constructed with the McDonalds Restaurant on Lot 1. As mentioned in the previous section, the percent imperviousness for ' this area has been assumed to be 71 % to 891/o in previous studies. For this study, the higher and more conservative percent impervious of 89% was used. ' Stormwater quality was briefly addressed in the original Drainage Report for the Tower Shoppes P.U.D. and stated that runoff from the site would "enter a permanent stormwater ' detention pond serving as a means to settle out suspended particles". However facilities that Addendum to the Final Drainage and Erosion Control Study Page 4 Tower Shoppes P.U.D. November 16, 2005 I 1 meet the current criteria were not constructed and thus this study and water quality enhancement design was prompted. ' 4.2 Extended Detention Basin Design The recommended water quality enhancement measure is the use of an extended detention ' basin (EDB) designed using guidelines set forth in the Urban Storm Drainage Criteria Manual, Volume 3 (2004). The proposed EDB is a sedimentation facility that will capture ' stormwater runoff from frequently occurring rainfall events and extend the emptying time to allow for pollutant removal through gravity settling. During the time in-between stormwater events the majority of the basin will remain dry. A permanent micro -pool for biological uptake is not included in the design because the total water quality capture volume is small and a significant amount of soluble pollutants are not expected. Additionally, since stormwater runoff is passing through grassy swales before entering the EDB, a presedimentation forebay was not included in this design. The design brim -full water quality capture volume required to allow a 40-hour drain time is 0.17 ac-ft. The pond has been designed with 3:1 side slopes and a variance request is included in the following sections. The proposed EDB is located in its final location and is sized to provide the required amount of water quality enhancement for all of the Tower Shoppes P.U.D. to be developed. The Iproposed pond will not need to be resized or reshaped. 4.3 Outlet Structure Design The proposed outlet structure is a drop box structure with a flow control plate designed to release frequently occurring storm events over a 40-hour period. The top of the drop box ' structure is equipped with a grate and the outlet pipe is designed to pass the 10-year storm. The proposed outlet pipe is a 18" RCP which will tie into the existing storm drainage inlet (Inlet CI-3) of the stormwater conveyance system constructed with the New High School as shown on the approved construction plans for the Tower Shoppes P.U.D. This system was designed to convey the 10-year developed flows from the Tower Shoppes site (Meline & Ireland, 1994) equal to 20.6 cfs. Peak flows from the 100-year storm from the Tower Shoppes site will pass over the 100-year emergency overflow spillway that will be constructed on the east and northeast sides of the EDB and pass on to the existing 10' wide concrete 100-year overflow channel on the south side of the New High School. Details of ' the design for the outlet structure are included in Appendix B. Addendum to the Final Drainage and Erosion Control Study Page 5 Tower Shoppes P.U.D. November 16, 2005 I I 1 I I [1 I 1 Figure 3 - Existing overflow channel south of the High School According to the approved Final Drainage and Erosion Control Study for Tower Shoppes P.U.D. by RBD, dated 9/9/95, the existing Fort Collins High School overflow channel was to be expanded to the south onto Lot 1 at the time Lot 1 was to be developed to accommodate 100-year flows from Basin 1 of Tower Shoppes PUD (Basins A+B+C+D of this report). The stormwater flows are now being directed to the new EDB with the minor storm events being treated and the major storm events passing through the pond via the proposed emergency spillway being provided. Thus the 10-foot wide expansion to the south of the existing sidewalk/overflow channel as previously designed by RBD and mentioned above is no longer needed. Therefore it is not necessary to construct the additional overflow channel with the development of Lot 1. Excerpts from the Final Drainage and Erosion Control Study for Tower Shoppes P.U.D. are included in Appendix C pages C-1 to C-9, and the approved Drainage and Erosion Control Plan by RBD, dated 5/95, for the Tower Shoppes PUD is included in the back pocket of this report. 5. EROSION AND SEDIMENT CONTROL 5.1 Erosion and Sediment Control Measures Erosion and sedimentation for the Sonic Drive -In (Lot 4) construction and the construction of the proposed water quality pond will be controlled on -site by use of silt fences, straw bale barriers, gravel construction entrances, and seeding and mulch. These measures are designed Addendum to the Final Drainage and Erosion Control Study Page 6 Tower Shoppes P.U.D. November 16, 2005 I F ' to limit the overall sediment yield increase due to construction as required by the City of Fort Collins. During overlot and final grading the soil will be roughened and furrowed perpendicular to the prevailing winds. Straw bale dikes will be placed along proposed swales. Erosion control effectiveness, rainfall performance calculations and a construction schedule are provided in Appendix D. Calculations were performed for only the Sonic Drive -In (Basin C, 0.76-acres) and the area being disturbed for the water quality pond which lies within the Limits of Construction shown on the Offsite Grading, Drainage and Erosion IControl Plan, page 5 of 7, Sonic Drive -In — Lot 4 Tower Shoppes P.U.D. (0.66-acres) ' 5.2 Dust Abatement During the performance of the work required by these specifications or any operations appurtenant thereto, whether on right-of-way provided by the City or elsewhere, the contractor shall furnish all labor, equipment, materials, and means required. The Contractor shall carry out proper efficient measures wherever necessary to reduce dust nuisance. Efficient measures shall be taken to prevent dust nuisance that has originated from the contractor's operations from damaging crops, orchards, cultivated fields, and dwellings, or causing nuisance to persons. The Contractor will be held liable for any damage resulting from dust originating from his operations under these specifications on right-of-way or elsewhere. 5.3 Tracking Mud on City Streets ^ It is unlawful to track or cause to be tracked mud or other debris onto city streets or rights -of - way unless so approved by the Director of Engineering in writing. Wherever construction vehicles access routes or intersect paved public roads, provisions must be made to minimize the transport of sediment (mud) by runoff or vehicles tracking onto the paved surface. Stabilized construction entrances are required per the detail shown on the Erosion Control Plan, with base material consisting of 6" coarse aggregate. The contractor will be responsible for clearing mud tracked onto city streets on a daily basis. ' 5.4 Maintenance All temporary and. permanent erosion and sediment control practices must be maintained and I repaired as needed to assure continued performance of their intended function. Straw bale dikes or silt fences will require periodic replacement. Sediment traps (behind straw bale I ' Addendum to the Final Drainage and Erosion Control Study Page 7 Tower Shoppes P.U.D. November 16, 2005 I ' barriers) shall be cleaned when accumulated sediments equal approximately one-half of trap storage capacity. Maintenance is the responsibility of the developer. ' 5.5 Permanent Stabilization A vegetative cover shall be established soon after grading is completed in order to reduce erosion and prevent the movement of sediments from the site. Suitable vegetative cover includes sod or using cover crops with mulch. Mulches that can be used include grass hay, small grain straw and processed materials such as erosion control blankets. Vegetation will not be considered established until a ground cover is achieved which is demonstrated to be mature enough to control soil erosion to the satisfaction of the City Inspector and to survive severe weather conditions. Contech Pyramat or other approved turf reinforcement matting is required at locations where flows are concentrated in order to prevent soil erosion. ' 6. VARIENCES The proposed EDB has sides slopes equal to 3H:1 V. It was graded in this way to minimize the amount of surface area taken by the pond and the impact it has on the previously approved building pad size. A variance is requested from Section 9.3 of the City of Fort Collins Storm Drainage Design and Construction Criteria Manual which requires banks of detention ponds to be no steeper than 4H:1 V slope to allow access to maintenance vehicles. Since the total width of the proposed pond is less than 40-feet and there will be paved areas immediately adjacent to the pond on the east and west for maintenance vehicles, the slightly steeper side slopes will not adversely affect the maintenance access. Additionally the side slope is not too steep to pose a safety hazard to people walking next to the pond on the existing Fort Collins High School sidewalk north of the proposed pond ' 6. CONCLUSIONS ' The proposed EDB located on the northeast corner of Lot 1 of the Tower Shoppes PUD and included in the proposed construction plans for Sonic — Horsetooth meets the current drainage design criteria for the City or Fort Collins with the exception of the 3:1 side slopes ' for which a variance is requested by means of this report. Water quality enhancement will be provided for the undeveloped portions of Lot 2, Lot 4 and the west half (parking area) of Lot ' 1 within the EDB. Stormwater detention for the difference between the old and new rainfall ' Addendum to the Final Drainage and Erosion Control Study Page 8 Tower Shoppes P.U.D. November 16, 2005 I ' standards for Lots 2 and Lot 4 can be accommodated within the existing regional detention pond (Pond 213) constructed with the New Fort Collins High School. The existing temporary drainage swales that were constructed with the McDonalds site will be reshaped ' so that they drain into the proposed EDB. Permanent and temporary erosion control measures will be used on the site during and after construction. 1 1 I 1 1 I 1 1 7. REFERENCES 1. "Addendum to Final Drainage and Erosion Control Study for the Tower Shoppes, P.U.D., Lot 3 (a.k.a. Pad `B') Temporary Drainage Utilities, RBD, Inc., August 1995. 2. City of Fort Collins, "Storm Drainage Design Criteria and Construction Standards" (SDDCCS), May 1984. 3. "Final Drainage Report for the New Fort Collins High School", Meline & Irelan, Inc., August 1994. 4. Letter Report RE: New Fort Collins High School Detention Pond Overtopping Analysis. Lidstone and Anderson, Inc, March 1995 5. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual", Volumes 1 and 2, dated June 2001, and Volume 3, dated September 1992. 1 Addendum to the Final Drainage and Erosion Control Study Page g Tower Shoppes P.U.D. November 16, 2005 11 1 i 1 11 1 11 1 1 1 11 1 1 1 1 u 1 1 APPENDIX A DETENTION CALCULATIONS 1 O LL Y Q lu a J J Q Z � QZ_ ILL O {L N O � p Z p c p W Z r W W W Z 0 00 U � LL + 0 W r r O Y QC W J 9 � m b i LL E O � W m j v O V W U N J S m m m U " v � as I-F V � m 3 OJ cg E LL J w N Q ry 2 O c `c 4 o W m E o F Q -IaF Z � E m N 0 t c � a J U W O = U z c w O J y U Ew z F u m N Q � v ^ 0 Z J m N s m d (A U Q 2 <Z d H o w�ZOO ' Old OF Fov-T COLLINS ' INTERPOLATED VALUES FOR 100 INTENSITIES Tc YEAR Value ' 5.00 9.0 YYY 5.10 9.0 5.0 5.30 8.9 8.9 5.40 8.9 5.50 8.8 ' 5.60 5.70 8.8 8.7 5.80 8.7 5.90 8.7 6.00 8.6 ' 6.10 8.6 6.20 8.6 6.30 8.5 6.40 8.5 6.50 8.5 60 e 6.70 8.4 6.80 8.4 6.90 8.3 7.00 8.3 7.10 8.2 ' 7.20 8.2 7.30 8.2 7.40 8.1 7.50 7.60 8.1 8.1 7.70 8.0 7.80 8•.0 7.90 8.0 8.00 7.9 ' 8.10 7.9 8.20 7.•8 / 8.30 7.8 ' 8.40 , 7.8 .8.50 7.7 8.60 7.7 ' 8.70 --7-.7 8.80 7.6 8.90 7.6 ' 9.00 9.10 7.6 ' 7.5 9.20 7.5 9.30 7.5 9.40 7.4 ' 9.50 7.4 9.60 7.3 9.70 7.3 9.80 7.3 ' 9.90 7.2 10.00 7.2 IDF -p�,TR A- Z Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 100-Yr Storm -OLD rainfall) Lot 2 + 4 PROJECT NAME: Tower Shoppes Drainage Study PROJECT LOCATION: Horserooth Road and Timberline Road, Fort Collins, CO COMPUTATIONS BY: J Zang DATE: 1111112005 100 yr storm, Cf = 1.25 DIRECT RUNOFF ICARRY OVER TOTAL REMARKS Des. Am A Cut Ic i O(100) from O(1 W) Ui1W)tot Design Point Design. (ac) (min) (hilly) (cfs) Pailrt es) (cts) III. A+C(Lo12+Lo14 1.54 0.93 6.6 8.40 11.97 12.0 release under old reamrail CmIQdIOI15 Q=CiA Q = peak discharge (cfs) C = runoff coefficient i = rainfall intensity (in/hr) from OLD City of Fort Collins OF curve A = drainage area (acres) old dev flows V (") V O co e- O �• � l0 C N Cl) 0 0 n u o u Q u a u Y n m F.to o O �Ud Q m J 7 ++ 0 v $ U m ai U Q po 43 a J Q , Q LL O p y cc c W L ¢ 3 W It J E> ya U O> 0 o z o o > O Q D d O m �6 + U F F c 0 O N dad o 0 > O W" O U Y > r 11 u0. p ~ o > u o d > u u _0 > a d u � O m CU E z� 0 o uiOz a)>> y O y z UO Q ac a F- 0 LTAa w Q ca = c p F w ca avFOUa It m 07 Cl) Cl) M Cl) N N t c) M w (n 0 0 0 a 0 0 U r m O O CD CD O c?O O O c; N m OI CY)O) V (D 1M N O (o N lO O (D 0) LL� co M M O O co O V O) V a N OO n Go (O LO N co CO O V 00 O CD N cO V 0 (O p •> c0 N V M O 'Q (D d' LO lO LO N h O M N O0 LO It0 N N M C LO O M O V M 7�'o N LO > r n N O N M N (D N (D O O LO N pp M r V D N M M O O O ` O Ln C (D (� v v M N N w (O LO 7 V T N O N M N O N ITM (D C N= p7 Cj OD M o 1- 0 0 r N w . c c ci6cococorLrivo mCi r F c G N O O m O N m IttLOD Co U) E 0 TM O � O T 0 0 v N J X h m 7 0 c c 0 a N m a a O L N 3 0 I 1 APPENDIX B EXTENDED DETENTION BASIN DESIGN 1 1 1 LJ 1 t 11 t Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility Designer: J. Zung Company: Interwest Consulting Group Date: November 11, 2005 Project: Tower Shoppes Drainage Study Location: Horsetooth and Timberline ' 1. Basin Storage Volume A) Tributary Area's Imperviousness Ratio (i = I,/ 100 ) B) Contributing Watershed Area (Area) C) Water Quality Capture Volume (WQCV) (WQCV =1.0' (0.91 ' 1'- 1.19' r`+0.78' 1)) D) Design Volume: Vol = (WQCV / 12) • Area' 1.2 2. Outlet Works A) Outlet Type (Check One) le = 89.00 % 1= 0.89 Area = 4.33 acres WQCV = 0.39 watershed inches Vol = 0.170 acre-feet x Orifice Plate Perforated Riser Pipe Other: B) Depth at Outlet Above Lowest Perforation (H) H = 4.40 feet C) Required Maximum Outlet Area per Row, (P.o) Ae = 0.13 square inches D) Perforation Dimensions (enter one only): i) Circular Perforation Diameter OR D = 0.375 inches, OR if) 2' Height Rectangular Perforation Width W = inches E) Number of Columns (nc, See Table 6a-1 For Maximum) nc = 1 number F) Actual Design Outlet Area per Row (AJ !b = 0.11 square inches G) Number of Rows(m) nr= 13 number H) Total Outlet Area (A.,) Am = 1.46 square inches 3. Trash Rack A) Needed Open Area: A, = 0.5' (Figure 7 Value)' Aa B) Type of Outlet Opening (Check One) C) For 2-, or Smaller, Round Opening (Ref.: Figure 6a): i) Width of Trash Rack and Concrete Opening (W.) from Table 6a-1 - - ii) Height of Trash Rack Screen (Hra) A,= 54 square inches x < 2- Diameter Round 2' High Rectangular Other. Wes= 3 inches H, = 83 inches Sheet 1 of 3 a ' Urban drainage-wgcv, EDB g' I 11112/2005, 4:09 PM Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation facility Designer: J. Zung Company: Interwest Consulting Group Date: November 11, 2005 Project: Tower Shoppes Drainage Study Location: Horsetooth and Timberline iii) Type of Screen (Based on Depth H), Describe if "Other" x S.S. #93 VEE Wire (US Filter) Other: iv) Screen Opening Slot Dimension, Describe if "Other' x 0.139" (US Filter) Other: v) Spacing of Support Rod (O.C.) 0.75 inches Type and Size of Support Rod (Ref.: Table 6a-2) #156 VEE vi) Type and Size of Holding Frame (Ref.: Table 6a-2) 3/8 in. x 1.0 in. flat bar D) For 2" High Rectangular Opening (Refer to Figure 6b): 1) Width of Rectangular Opening (W) W = inches ii) Width of Perforated Plate Opening (W., = W + 12") W.n, = inches iii) Width of Trashrack Opening (W,,,b.) from Table 6b-1 Wap,,;,,o = inches iv) Height of Trash Rack Screen (HTa) HTa = inches v) Type of Screen (based on depth H) (Describe if "Other") Klemp'" KPP Series Aluminum Other. vi) Cross -bar Spacing (Based on Table 6b-1, Klemp'" KPP inches Grating). Describe if "Other" Other. vii) Minimum Bearing Bar Size (Klemp" Series, Table 6b-2) Based on depth of WQCV surcharge) 4. Detention Basin length to width ratio 8.00 (UW) 5 Pre -sedimentation Forebay Basin - Enter design values A) Volume (no less than 5% of Design Volume from 1D) acre-feet B) Surface Area acres C) Connector Pipe Diameter inches (Size to drain this volume in 5-minutes under inlet control) D) Paved/Hard Bottom and Sides yes/no S-.;l- Urban drainage-wgcv, EDB Sheet 2 of 3 ' i 1 11/12/2005, 4:09 PM ' Design Procedure Form: Extended Detention Basin (EDB) - Sedimentation Facility Sheet 3 Designer: J. Zung Company: Interwest Consulting Group Date: November 11, 2005 Project: Tower Shoppes Drainage Study Location: Horsetooth and Timberline 6. Two -Stage Design - See Figure EDB-1 A) Top Stage (Depth D.r,,o = 2' Minimum) D„,p = feet Storage= acre-feet B) Bottom Stage Depth (Das = 1.0' Minimum, 2.0' Maximum) D. = feet Bottom Stage Storage (no less than 3 % of Design Volume (0.0051066650421 acre-feet. Storage= acre-feet Surf. Area= acres C) Micro Pool (Minimum Depth = the Larger of Depth= feet 0.5' Top Stage Depth or 2.5 Feet) Storage= acre-feet _ Surf. Area= acres D) Total Volume: Vole,=Storage from SA+6A+6B VDIM= acre-feet (Must be > Design Volume in 1 D, or 0. 17022216807 acre-feet.) 7. Basin Side Slopes (Z, horizontal distance per unit vertical) Z = 3.00 (honzontal/vertical) Minimum Z = 4, Flatter Preferred NOTE: Basin sideslo a exceeds recommended limit 8. Dam Embankment Side Slopes (Z, horizontal distance) - Z = 3.00 (honzontal/vertical) per unit vertical) Minimum Z = 3, Flatter Preferred 9. Vegetation (Check the method or describe *Other") x Native Grass Irrigated Turf Grass Other. Notes: 53 Urban drainage-wqcv, EDB 11/12/2005, 4:09 PM ,1 STRUCTURAL BMP DETAILS DRAINAGE CRITERIA MANUAL (V. 3) 1 Orifice Perforation Details A-7� Wplote = Nor, + 6 inches (minimum) Structural Steel Channel -1.1 0 _ �. Farmed Into Concrete, To Y WConc (see below) Span Width Of Structure. �¢^f1y�I See Figures 6-a, 6-b P T B a o of a to Permanent 0-1 Water Surface a J J m2.. Minimum 4 ox. o a Circular Openings: Wcanc Obtained From Table 6a-1 Rectangular Openings: Wconc. = (Width of Rectangular Perforation W) + 12" Rectangular Openings: Wope„i„g (see Figure 6-b) Obtained From Table 6b-1 So, see , see W figure 5 Figure 5 0 0 0 o 000 0 0 0 0 0 0 a o000a o o 000 -0000 000 0 0 a a 0 0 0 000 oa o Q o Example Perforation Patterns Note: The goal in designing the outlet is to minimize the number of columns of perforations that will drain the WQCV in the desired time. Do not, however, increase the diameter of circular perforations or the height of the rectangular perforations beyond 2 inches. Use the allowed perforation shapes and configurations shown above along with Figure 5 to determine the pattern that provides an area per row closest to that required without exceeding it. Urban Drainage and Figure 4 Flood Control District Orifice Details for Drainage Criteria Manual (V.3) Draining WQCV Re: Vd—au.t Detaie.d.g Figure 4—Orifice Details for Draining WQCV. Rev. 12/28/2004 Urban Drainage and Flood Control District P3-4 DRAINAGE CRITERIA MANUAL (V. 3) Orifice Plate Perforation Sizing STRUCTURAL BMP DETAILS Circular Perforation Sizing Chart may be applied to orifice plate or vertical pipe outlet. Hole Dia (in) ' NOIe Oia (in) Min. Bc (In) area per Raw lsq in n=1 n=2 n=3 1/4 0.250 1 0.05 0.10 I 0.Ib 5 F16 a313 2 OA8 0.15 0.23 3 8 0.375 2 0.11 0.22 0.33 7/16 .43 2 `O.tS 0.30 0.45 1/2 0.500 2 0.20 0.39 0.59 9/I6 0.563 3 0.50 O75 5 8 a625 3 0.31 0.61 0,92 11/16 0.688 3 0.37 O74 1.11 34 0.750 3 0.44 0.88 1.33 13 16 0,813 3 0.52 1.04 1.56 78 0.875 3 0.60 1.20 1.80 15 16 0,938 3 0.69 1.38 2.07 1 io00 4 0.79 1.57 2.36 1 1 16 1.063 4 0.89 1.77 2.66 1 1 8 1.125 4 0.99 1.99 298 1 315 1.188 4 1.11 2.22 3.32 1 14 1.250 4 1.23 2.45 3.68 1 5 16 1.313 4 1.35 2.71 4.O6 1 3 8 1.375 4 F48 2.97 4.45 1 7 16 1 1.438 4 1.62 3.25 4A7 1 1 2 1.500 4 1.7] 3.53 5.30 1 9 16 1.563 4 1.92 3.83 5,75 1 5 8 1,625 4 2.07 4.15 6.22 1 11 16 1.688 4 2.24 4.47 6.71 1 3 4 1.750 4 2,41 4.51 722 1 13 I6 1.813 4 2.58 5,16 774 1 78 1.875 4 2.76 552 8.28 1 15 16 1.938 4 295 5.90 Re 8.84 2 2.000 4 3.14 9.42 n = Number of columns of perforations Minimum steel plate thickness 1/4 5/16 3/8 " • Designer may interpolate to the nearest 32rd inch to better match the required area, if desired. Rectangular Perforation Sizing Only one column of rectangular perforations allowed. Rectangular Height = 2 inches Rectangular Width (inches) _ Required Area per Row (so in) 2" Rectangular Hole Width Min. Steel Thickness 5" 4 6" 1/4 7" 5/32 $„ 5/16 ,. g" 11/32 " 10" 3/g .. 7>10" 1/2 ,. Urban Drainage and Figure 5 Flood Control District WOCV Outlet Orifice Drainage Criteria Manuol (V.3) Perforation Sizing File: U-Outlet Delails.dva Figure 5-WQCV Outlets Orifice Perforation Sizing. Rev. 12/28/2004 Urban Drainage and Flood Control District SD-7 STRUCTURAL BMP DETAILS DRAINAGE CRITERIA MANUAL (V. 3) Note: Vertical WOCV Trash Racks are shown in Figures 6, 6-a, and 6-b for suggested standardized outlet design. Adverse -Slope Trash Rack design may be used for non -standardized designs, but must meet minimum design criteria. Stru chiral Steel Channel Stainless Steel Balls Formed Into Concrete. wcone. or Intermittent Welds, See Figures 6-a, 6-le q!-� See figures 6-a, 6-b o H _ Varies 2*-0" to 6'-0" 2 -4" (minimum) A WOCV Trash Racks: Elevation 1. Well —screen trash racks shall be stainless steel and shall be attached by intermittent welds along the edge of the mounting frame. 2. Bar grate trash racks shall be aluminum and shall be bolted using stainless steel hardware. 3, Trash Rack widths are for specified trash rack material. Finer well —screen or mesh size than specified is acceptable, however, trash rack dimensions need to be adjusted for materials having a different open area/gross area ratio (R value) 4. Structural design of trash rack shall be based on full hydrostatic head with zero head downstream of the rack. Overflow Trash Racks: - 1. All trash racks shall be mounted using stainless steel hardware and provided with hinged and lockable or boltable access panels. 2. Trash racks shall be stainless steel, aluminum,or steel. Steel trash racks shall be hot dip galvanized and may be hot powder painted after galvanizing. 3. Trash Racks shall be designed such that the diagonal dimension of each opening is smaller than the diameter of the outlet pipe. 4. Structural design of trash rock shall be based on full hydrostatic head with zero head downstream of the rack. Urban Drainage and Figure 6 Flood Control District Suggested WOCV Outlet Standardized Drainage Criteria Manual (V.3) Trash Rack Design File: vs -outlet aemo..d.y Figure 6--Suggested WQCV Outlets Standardized Trash Rack Design. SD-8 Rev. 12/28/2004 Urban Drainage and Flood Control District DRAINAGE CRITERIA MANUAL (V. 3) STRUCTURAL BMP DETAILS B.. 4._0.. B.. Bolt Down or C8x1875 American Standard Lock Down Structaral Steel Channel. Trash Rack Attached By Welding Rack Swivel Hinge Tub- lar Trash Rack W CV evel On 6" a" Centers - }or4 1r— Options Co H Flow Control Varies C C -- Orifice Plate 2'-a. U.S. Filter- Stainless Steel Perforated to Steel Well -Screen C Flow ontrol 6'-0" (or equal) Per Tables plate - T 6a-1, 6a-2 Micro Pool W.S. Outlet Pipe 18" Min. 3" Minimum L C60B.lS American — — — Standard Structural Steel Channel Formed _ 2.-4.> Into Concrete Bottom Minimum And Sides Of Wes. - Rock Attached - ByyIntermit R\\. Section A —A, \ From Figure 6, Circular Openings Only Well -Screen Frame Attached To Channel By Intermittent Welds Steel Perforated Flow Control . Plate Flow Trash Rack Attached By Intermittent Welding All Around 6' Min. Section B—B — Plan View From Figure 6, Circular Openings Only Limits for this Standardized Design: 1. All outlet plate openings are circular. 2. Maximum diameter of opening = 2 inches. -U.S. Filter, St. Paul, Minnesota. USA Urban Drainage and Flood Control District Drainage Criteria Manual (V.3) File. NO -Outlet avta ls.dvg Stainless Steel Support Bars No. 93 Stainless Steel (U.S. Filter' or Equal) Wires Flow F--- 0.139" 0.090" Section C—C From Figure 6. Circular Openings Only R Value = (net open area)/(gross rack area) = 0.60 Figure 6—a Suggested Standardordlzed Trash Rack and Outlet Design For WOCV Outlets With Circular Openings Figure 6a—Suggested Standardized Trash Rack and Outlet ueslgn Tor WQCV Outlets With Circular Openings. Rev. 12/28/2004 Urban Drainage and Flood Control District 61•a STRUCTURAL BMP DETAILS DRAINAGE CRITERIA MANUAL (V. 3) 1 Table 6a-1—Standardized WQCV Outlet Design Using Circular Openings (2" diameter maximum) Minimum Width (Wopening) of Opening for a Well -Screen Type Trash Rack. Requires a minimum water depth below the lowest perforation of 2'4'. See Figure 6-a for Explanation of Terms. Maximum Dia. of Width of Trash Rack Opening (W.o ..) Per Column of Holes as a Function of Water Depth H Below Lowest Perforation Circular Opening (inches) H=2.0' H=3.0' H=4.0' H=5.0' H=6.0' Maximum Number of Columns < 0.25 3 in. 3 in. 3 in. 3 in. 3 in. 14 < 0.50 3 in. 3 in. 3 in. 3 in. 3 in. 14 < 0.75 3 in. 6 in. 6 in. 6 in. 6 in. 7 < 1.00 6 in. 9 in. 9 in. 9 in. 9 in. 4 < 1.25 9 in. 12 in. 12 in. 12 in. 15 in. 2 < 1.50 12 in. 15 in. 18 in. 18 in. 18 in. 2 < 1.75 18 in. 21 in. 21 in. 24 in. 24 in. 1 < 2.00 21 in. 24 in. 27 in. 30 in. 30 in. 1 Table 6a-2—Standardized WQCV Outlet Design Using Circular Openings (2° diameter maximum). US FilterT Stainless Steel Well -Screen' (or equal) Trash Rack Design Specifications. Max. Width of Opening Screen #93 VEE Wire Slot Opening Support Rod Type Support Rod, On -Center, Spacing Total Screen Thickness Carbon Steel Frame Type 9" 0.139 #156 VEE %" 0.31' 3/e"x1.0"flat bar 18" 0.139 TE .074"x.50" 1" 0.655 %" x 1.0 angle .24" 0.139 TE .074"x.75" 1" 1.03" 1.0" x 1"%" angle 27" 0.139 TE .074"x.75" 1" 1.03" 1.0" x 1'%" angle 30" 0.139 TE .074"x1.0" 1" 1.155" 1 '/4"x 1'/2" angle 36" 0.139 TE .074"x1.0" 1" 1.155" 1 '/4"x 1'/2" angle 42° 0.139 TE .105"x1.0" 1" 1.155" 1 '/4"x 1Wangle US Filter, St. Paul, Minnesota, USA SD-10 Rev. 12/28/2004 Urban Drainage and Flood Control District ' g"� EXTENDED DETENTION BASIN 1 Stage/Storage LOCATION: Tower Shoppes Drainage Study COMPUTATIONS BY: J. Zung SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 11/11/2005 1 I �J .i V=1/3d(A+B+sgrt(A"B)) where V = volume between contours, ft' d = depth between contours, It A = surface area of contour Lot 2 + Lot 4 + west Lot 1 Sub -basins A+B+C Stage (ft) Surface Area W) Incremental Storage (ac-ft) Total Storage (ac-ft) 33.1 0 0.00 0.00 34.0 59 0.00 0.00 35.0 737 0.01 0.01 36.0 2289 0.03 0.04 37.0 4387 0.08 0.12 37.5 5899 0.06 0.18 38.0 5899 0.07 0.24 38.5 5977 0.07 0.31 Water Quality Capture Volume Required = 0.17 Water Quality Capture Volume Provided = 0.18 WQCV elev spill elevation berm elevation ' tower shoppes pond volumes Interest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, 10-Yr Storm - updated rainfall data) LOCATION: Tower Shoppes PUD PROJECT NO: 1025-021-00 COMPUTATIONS BY: J. Zung DATE: 61412005 DIRECT RUNOFF CARRYOVER ITOTAL REMARKS Daspn Point Tributary Sub -basin A (x) CCf- W, (min) (inmr) O(10) (ds) from Design Point 0(10) (Qs) O(10)ux I (cfs) 1 1(from Toner Shop,,es Rpt)- 6.57 0 4 102 3.77 1&. 18.3 DESIGN FLOW FOR EDa OUTLET 2 fmm Tvwr Shoppes 3.76 O.as 5.7 4.61 14.74 14.7 *Note* C value, Tc and Area from Drainage and Erosion Control Report for Tower Shoppes PUD If 995) Equations: O=C,CiA O = peak discharge (cfs) C = runoff coefficient Ct = frequency adjustment factor i = rainfall intensity (inthr) from City of Fort Collins OF curve (4/16/99) A= drainage area (acres) I=41.44 t(to. tcf0 4 new dme flows q- _ /O i r r r r r II Interwest Consulting Group RATIONAL METHOD PEAK RUNOFF (City of Fort Collins, Ill Storm • updated rainfall data) PROJECT NAME: Tower Shoppes PUD PROJECT LOCATION: 1015-011-00 COMPUTATIONS BY: 1 Zwg DATE: 61412005 DIRECT RUNOFF ICARRYOVER ITOTAL IRENvuois pea. Pant Area Design. A (x) CCt- I (min) i (W a(IM) (cis) tom Design Point a(loo) (da) O(lW)tw (tls) t 1 from Toner ShpppesR q' 8.5] 093 ].1 Bao 53.A 53.8 DESIGN FLOW FOR SPILLWAY 2 from TonerShoppes R 3]8 1 to 50 1 374 'Note' C value, Tc and Area from Drainage and Erosion Control Report for Tower Shoppes PUD (1995) Equations: O=Cr CiA 0 = peak discharge (cfs) C = runoff Coefficient Ct = frequency adjustment factor i = rainfall intensity (inthr) from City of Fort Collins IDF curve (4116199) A= dreinage area (acres) ,=e4.eev(10. Mf. new dev flans 11 Worksheet for EDB pond outlet Flow Element: Circular Pipe Friction Method: Manning Formula Solve For: Normal Depth .Input -Data Roughness Coefficient: 0.013 Channel Slope: 0.03000 ft/ft Diameter: 1.50 ft Discharge: 18.30 _ fP/s Results Normal Depth: 1.24 ft Flow Area: 1.56 ft' Wetted Perimeter: 3.42 ft Top Width: 1.14 ft Critical Depth: 1.45 ft Percent. Full: 82.5 % . Critical Slope: 0.02670 ft/ft Velocity: 11.73 ft/s Velocity Head: 2.14 ft Specific Energy: 3.38 ft Froude Number. 1.77 Maximum Discharge: 19.57 ft3/s Discharge Full: 18.19 ft'/s Slope Full: 0.03035 ft/ft Flow Type: Supercritical GVF Input Data Downstream Depth: 0.00 ft Length: 0.00 ft Number Of Steps: 0 GVF Output Data Upstream Depth: 0.00 ft Profile Description: N/A Profile Headloss: 0.00 ft Average End Depth Over Rise: 0.00 % Normal Depth Over Rise: 0.00 % Downstream Velocity: 0.00 ft/s I- P- Worksheet for EDB pond outlet ' Upstream Velocity: 0.00 ft/s Normal Depth: 1.24 ft Critical Depth: 1.45 Channel Slope: 0.03000 It Nft Critical Slope: 0.02670 ft/ft 1 i LI 7 Li F 1 1 1 1 -.ts Worksheet for Broad Crested Weir - 1 Project Description Flow Element: Broad Crested Weir Solve For: Crest Length Discharge: 53.60 ft/s Headwater Elevation: 4938.50 ft Crest Elevation: 4938.00 - ft Tailwater Elevation: 4937.50 ft Crest Surface Type: Gravel Crest Breadth: 4.00 ft IRTs—ultsIM Crest Length: 56.29 ft Headwater Height Above Crest: 0.50 ft Tailwater Height Above Crest: -0.50 ft Weir Coefficient: 2.69 us Submergence Factor: 1.00 Adjusted Weir Coefficient: 2.69 US Flow Area: 28.15 ft' Velocity: 1.90 tt/s Wetted Perimeter. 57.29 ft Top Width: 56.29 ft Y 0 Z Q N y� LL F z �w 0 U Z cp U LL QO u� w 2 F K- J h E� N { O C i^y V N m II O Y N x�9:N u0 V � N mm b o v LL 0 0 J _ q ct crn ==e m o,o b U 0 o0 W o� G � o�m w L_ N ag ~ aEn b O V d' vl 0 N b N U 0 U b C W V+ o O tW Z~ � b o z_ u 0 � a b m J U a � o r a a innQQ �r F6,) 'CJe-S v 5woje �c Sdv� c- Lot RATtONAL of Fort C HOD PEAK 00 Yrr RUNOFF yStorm) — /� LOCATION: Tower Shoppes Drainage Study ,{.;_�� S''� ��-� PROJECT NO: I025-021-00 l Y COMPUTATIONS BY: J. Zung DATE: 6/28/2005 100 yr storm, Cf = 1.25 Des. Point Area Design. A (ac) C Cf 4 (min) i (in/hr) C(100) (cfs) from Design Point 0 (100) (cfs) Q(100)lot (cfs) t C Sonic 0.76 1.00 5.5 9.54 Z3 7.3 to east temp. swale Q=CIA Q = peak discharge (cfs) C = runoff coefficient i = rainfall intensity (in/hr) from City of Fort Collins IDF curve (4/16/99) A = drainage area (acres) i = 84.682 t (10+ tc)° 7975 Sonic flow As 6 -1(0-. Extended Detention Basin ' Emergency Overflow Spillway Sizing ' LOCATION: Tower Shoppes Drainage Study PROJECT NO: 1025-021-00 COMPUTATIONS BY: J. Zung SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 11/11/2005 top of b8rm I Equation for flow over a broad crested weir b Q = CLH' A spill elevation where C = weir coefficient = 2.6 4 L _> H = overflow height L = length of the weir Spill elevation = WQCV water surface elevation + 0.5' freeboard Design spillway with 0.5 ft flow depth, thus H = 0.5 ft Size the spillway assuming that the pond outlet is completely clogged. Water Quality EDB Q (100) = 53 cfs (peak flow into pond, Basin 1, new rainfall) Spill elev = 4938.00 ft = WQCV ELEV + 0.5' I Min top of berm elev.= 4938.50 Weir length required: L = 58 ft Use L = 60 ft v = 1.72 ft/S 1 J8 - 0 , TOWER SHOPPES EDB 10-yr Event, Outlet Sizing LOCATION: Tower Shoppes Drainage Study PROJECT NO: 1025-021-00 COMPUTATIONS BY: J. Zung , SUBMITTED BY: INTERWEST CONSULTING GROUP DATE: 11/11/2005 Submerged Orifice Outlet: release rate is described by the orifice equation, Qo = CA sgrt( 2g(h-Ea)) , where Qo = orifice outflow (cfs) Co = orifice discharge coefficient g = gravitational acceleration = 32.20 ft/s Ao = effective area of the orifice (ft`) Eo = geometric center elevation of the orifice or d/s HGL (ft) h = water surface elevation (ft) Pond Name Qo = 20.60 cfs (10-yr developed from Basin 1 - per Tower Shoppes Drainage) outlet pipe dia = D = 18.0 in Invert elev. = 4933.10 ft (inv. "A" on outlet structure) Eo = 4933.10 ft (d/s HGL from Flowmaster) h = 4937.50 ft - WQCV elevation Ca = 0.65 solve for effective area of orifice using the orifice equation A. = 1.883 ft` = 271.1 in` orifice dia. = d = 18.58 in Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering) , d/ D = 1.03 kinematic viscosity, v = 1.22E-05 ftz/s Reynolds no. = Red = 4Q/(ndv) = 1.39E+06 Ca = (K in figure) = 0.65 check Use d = 18 in = OUTLET PIPE DIAMETER A o = 1.767 ft` = 254.47 in , Qmax = 19.34 cfs I 8_ia I Worksheet for East Temp. Swale Flow Element: Friction Method: Triangular Channel Manning Formula Solve For: Normal Depth ' Input Data Roughness Coefficient: 0.050 Channel Slope: 0.01500 Rift Left Side Slope: 8.00 ft/ft (H:V) Right Side Slope: 8.00 ft/ft (H:V) Discharge: 7.30 ft/s Results Normal Depth: 0.71 ft Flow Area: 4.02 W Wetted Perimeter: 11.44 ft Top Width: 11.35 ft Critical Depth: 0.55 ft Critical Slope: 0.05649 ft/ft I Velocity: Velocity Head: 1.81 0.05 ft/s ft Specific Energy: 0.76 ft Froude Number. 0.54 Flaw Type: Subcritical ' MF Input Data Downstream Depth: 0.00 ft Length: 0.00 ft 1 Number Of Steps: 0 FVF Output Data Upstream Depth: 0.00 ft 1 Profile Description: N/A Profile Headloss: 0.00 ft Downstream Velocity: 0.00 ft/s ' Upstream Velocity: 0.00 ft/s - Normal Depth: 0.71 ft Critical Depth: 0.55 ft Channel Slope: 0.01500 ft/ft Critical Slope: - 0.05649 Rift r- L 1 I 11 11 I 11 r I I I I I I I 11 I r APPENDIX C EXCERPTS FROM OTHER REPORTS 1 ' FINAL DRAINAGE AND EROSION CONTROL STUDY . TOWER SHOPPES P.U.D. CITY OF FORT COLLINS June 7, 1995 1 ' ' Prepared for: W. W. Reynolds Companies 1600 Specht Point Drive, Suite -El Fort Collins, Colorado 80525 ' Prepared by: RBD, Inc. Engineering Consultants 1 209 South Meldrum Street Fort Collins, Colorado 80521 (303) 482-5922 RBD Job No. 088-015 C-I I. lop FINAL DRAINAGE AND EROSION CONTROL STUDY TOWER SHOPPES P.U.D. CITY OF FORT COLLINS GENERAL LOCATION AND DESCRIPTION A. Location The Tower Shoppes project is located in the southeast portion of Fort Collins, Colorado. This project is bounded on the south by Horsetooth Road, on the west by Timberline Road, and on the north and east by the new Fort Collins High School. The tract on which the project is located contains approximately 11.74 acres and will consist of commercial development. The project site is shown on the Vicinity Map in the Appendix. More particularly, the site is situated in the southwest quarter of Section 29, Township 7 North, Range 68 West of the 6th P.M., City of Fort Collins, County of Larimer, State of Colorado. B. Description of Property The site of the Tower Shoppes P.U.D. is presently undeveloped land. Previous use for the site was agricultural. The existing site is presently open ground covered with native grasses with several abandoned irrigation trenches running in the east -west direction. Currently, the site topography is uniformly sloping toward the northeast comer at approximately 1.66%. An abandoned concrete irrigation diversion box is located in the southwest comer of the site. DRAINAGE BASINS AND SUB -BASINS A. Major Basin Description The project site is located in the Foothills Drainage Basin and is included in the Overall Drainage Study for the Pinecone P.U.D. B. Sub -Basin Description Flows from the site, in a developed condition, were included as part of the rvtnnaP CtlifIV nr tea ,acent ew ort ii1111ms I .;: School, as prepared by Meline & Irelan, Inc. A portion of that report ; area are included in the appendix of this report. map Within the study by Meline & Irelan, the Tower Shoppes P.U.D. was split into 1 L� F I I L r I I CI C -z ' two sub -basins. The western basin (approximately 6 acres) was assumed to flow in a northeasterly direction with 10 yr. flows intercepted by a curb inlet and 'carried by the school storm sewer system to detention ponds located along the east edge of the school property. The 100 yr. flows for this basin were to be conveyed by a shared overflow channel between the school and commercial buildings then by overland sheet flow to the ponds. Runoff from the eastern basin (approximately 7 acres) also flows in a nort east direction with 10 yr. flows intercepted and carried by the schools' sewer system to detention ponds, and 100 yr. flows overflowing the parking lot and being conveyed by sheet flow to swales leading to the detention ponds.' M. DRAINAGE DESIGN CRITERIA A. Regulations ' The City of Fort Collins Storm Drainage Design Criteria is being used for the subject site. The criteria established by the Final Drainage Report for the New Fort Collins High School, by Meline & Irelan, dated November, 1993, which includes requirements of the Pinecone Overall Drainage Study will also be adhered to for this project. B. Development Criteria Reference Constraints and Comparison The criteria established by the Final Drainage Report for the New Fort Collins ' High School, prepared by Meline & Irelan, dated November, 1993, will be used for this site. As detailed in the drainage report for the New Fort Collins High School, the Tower Shoppes site was divided into Basins 2 and 3 (west and east respectively, see portion of overall drainage map in appendix). Maximum anticipated ' developed 10 yr. runoff, as detailed in the M & I report to be intercepted and conveyed by the school system, for these basins respectively are 20.6 cfs and 23.9 cfs. As designed in this report, the runoff from these two basins are 20.9 cfs and 18.2 cfs, respectively. As can be seen, the flow value from Basin 2 is 3 cfs higher than anticipated. We feel that this situation is acceptable because the storm sewer which serves this basin (shown on page 16 of this report) is not operating at full capacity, and can handle the additional 0.3 cfs. Basin 3 falls below its design value, so the runoff from it is acceptaW' e. The report by Meline & Irelan addressed 100 yr. flows from the subject site as being conveyed by a combination of storm sewer, overflow channel, and overland sheet flow to Detention Pond 213 of the Pinecone Overall Drainage Plan. Maximum anticipated developed 100 yr. flows from the entire site was 77.04 cfs, ' 2 C - 3 I I1W as calculated in this report, with values from the Meline & Irelan report. As , calculated in this report the 100 yr. design flow is 70.69 cfs, thus complying with , the values from the New F.C.H.S. Drainage Report. G. As per the SWMM model used in the New F.C.H.S. report, Basins 2 and 3 of °'o that report were modeled using percent impervious values of 89 % for Basin 2 and 85% for Basin 3. This report by RBD, Inc. shows the same Basin 2 (Basin 1 of this report) with a percent impervious value of 71.8% and Basin 3 (Basins 2 and 3 of this report) at a value of 79.4%. Therefore, the Tower Shoppes P.U.D. values comply with the original assumptions used in the sizing of Regional Detention Pond 213. ' C. Hydrological Criteria The rational method was used to determine runoff peak flows from the site. The 10 and 100 year rainfall criteria, obtained from the City of Fort Collins, will be utilized. This criteria is included in the appendix. D. Hydraulic Criteria All calculations within this report have been prepared in accordance with the City of Fort Collins Storm Drainage Criteria. E. Variances from Criteria No variances from City of Fort Collins Storm Drainage Criteria are being sought for this project. DRAINAGE FACILITY DESIGN A. General Conceit As per the Pinecone Overall Drainage Plan, all on -site developed flows from Basin 1 of this report, for the Tower Shoppes site, will be conveyed by parking lot sheet flow and gutter flow to a 12' Type 'R' inlet along the north line of the property, where it outlets to a 24" storm sewer, ties into the New F.C.H.S. existing MH -3A and finally disperses into the aforementioned Regional Detention Pond 213. This Regional Detention Pond has already been constructed and sized to accept the flows from the Tower Shoppes P.U.D. Basin 2 flows will be conveyed by sheet flow and curb and gutter to a 10' Type 'R' inlet along the east line of the .property, and then enter a 24" storm sewer, which will tie to an existing 24" stub from a 12' Type 'R' inlet on the New F.C.H.S. site, called CI-3, which is part of that site's drainage system. Though not directly on -site, 3 C-y Basin 3 has been included in the runoff calculations in order to comply with the Y format for the New Fort Collins High School Drainage Report. -utM The 100 yr. flows will overflow the storm sewer system into a shared concrete G� channel, after ponding to a deptho anen ow overland to etention ' Pond 213. Half of this channel as een construct as part o t e ew F.C.H.S., and the Tower Shoppes eve oper is response a or i s completion. The design or the overflow pa used y e lg sc�l -was u� ' for the Tower Shoppes P.U.D. and this design was checked for consistency with the more recent flow results of this report. It was found to be capable of handling the new values calculated by the Tower Shoppes P.U.D. report. Runoff from Basin 4, which is the adjacent half -street portion of Timberline Road, bordering the Tower Shoppes property on the west, will flow by curb and 1 gutter to an existing 7' Type 'R' curb inlet, which outlets to the Foothills Basin Regional Channel. Flows from this basin do not enter the site. No on -site detention is intended for the site. Regional Detention Pond 213, which exists along the east edge of. the New Fort Collins High School property, has been sized to accommodate flows from the Tower Shoppes P.U.D. and the ' in this report comply with values used in the sizing of that pond. calculations ' Included in the back pocket of thisreportis the Tower Shoppes P.U.D Final Drainage and Erosion Control Plan. 1 B. Specific Details Sub -basin Design Consistent with the New F.C.H.S. Drainage Report, the subject site is separated into two drainage sub -basins. It is proposed that all on -site developed 10 yr. ' flows from these basins be colfected. by curb inlets which will tie into the New F.. stormwater system at the designed locarlurfs.i ng depth of 0.50 ft. all on -site developed flows in excess of the 10 yr. event will ' either enter a drainage channel or sheet flow to detention ponds on the school site. ' No off -site flows will enter the Tower Shoppes site. However, Basin 3 of the New F.C.H.S. Drainage Plan has been split into two sub -basins, Basin 2 and Basin 3, for this report (see included Final Drainage and Erosion Control Plan). ' Basin 3 includes offsite flows from the north half of Horsetooth Road, a portion of the high school's south parking lot, and the school's courtyard adjacent on the ' north. Although Basin 3 flow is not from the Tower Shoppes subject site, it is combined with on -site flows to aid comparison to the overall plan for the New 4 C-5 u F.C.H.S. site. Roof Drain System and On -site Storm Drain System The Anchor Tenant building will have a.roof drain system. The arcitect for this tenant has stated that the downspouts will be located along the back (east) side of the building and drain onto the parking lot pavement and in turn sheet flow to the 10' Type 'R' curb inlet for Basin 2. The remaining structures will have gutter systems which will drain onto the ground and overland flow to basin outlets. The proposed curb inlets and storm drain piping will collect all surface runoff flows less than or equal to the 10 yr. storm. Flows in excess of the 10 yr. event will be conveyed overland to Regional Detention Pond 213. There is no on -site detention intended at the inlets. Existing Inlets There is an existing 12' curb inlet at the outlet of the overflow channel. This inlet is intended for collecting all 10 yr. flows and smaller for Basin 3 of this report. As part of the Tower Shoppes P.U.D. project, we will tie to this inlet with a 24" storm sewer to convey flows from Basin 2 of this report. Existing Detention Pond The existing Regional Detention Pond along the east edge of the school site was sized in the Final Drainage Report for the New F.C.H.S. The developed flows calculated for the Tower Shoppes P.U.D. comply with the flow values anticipated in the final design of these ponds. STORMWATER QUALITY A. General Concept It is now required that the water quality of stormwater runoff be addressed on all final design utility plans:' For this study, we have considered the downstream r r impacts of the stormwateunoff. Since the site is intended for retail sales, the nature of the runoff will not be hazardous. Stormwater which is released from the site will enter a permanent stormwater detention pond serving as a means to settle out suspended particles. 5 r_ - l 1 I I 1 0) m m U ' W CV ao 0 0 a� m C O ' (0 Q' N O N N 7 1 C9 > U d .N O C1 ' U N L N ' � N a is W U U ' O N Cn L N W 1w N O L H i 4/ fl L C- 1 IN MimiHill I 111110111111111111pieC �1110 i��i � ON I �B" PLUG W/T.B. F.H. ASSEMBLY 5- \ C &G Xr SWIVEL SV. Or GATE VALVE\--\ BTM. Ir WATERLINE EL. 34.7 TOP STORM SEWER EL 31.8- 2' 2r STUB SOUTH INV E = 29.47 INV S = 29.97 INV NW= 29.94 INV NE = 29.75 CI-3 0 21;28725.7 CURB INLET C11-11 T.C. 39.00 15' TYPE -A y INV."" 30.85 212867 my",S 30.65 IN N 32.60 0 W/GRAVEL FILTER 1 SEE EE D-25. N SHEET 01207 :4.) 212870&7 Lot; lo, Ir 139' 24" BEND Ifr BE'ND-"" WYE -- 1'r as, 1128718. O INV 34.01 it 1O 212871 -C IN 3 ��4 Wit - �tg C WYE W/PLUG (TYP) Ir 45' BEND INV 37.35 2128790 tp 2128866.0 212 9.2 Ir WYE 64. to vo 14 2- METER VAULT a 14 OtYO2 SEE DETAIL Ir 45' BEND FOF INV. 37.52 24 �2 ;-,0620� 2128 68.5 9 4" PLUG INV. 37.52 ir WYE W/PLUG (TYP) 4- 2129040.2 BLDG PAD OUTLINE EI-411.83 WYE - ■ w WYE 32.47 mv N 31.17 FINAL DRAINAGE REPORT for NEW FORT COLLINS HIGH SCHOOL Prepared by i 1 Meline & Irelan, Inc. Consulting Engineers 4710 South College Avenue Fort Collins, CO 80525 C-10 I areas draining directly to the north and south detention ponds have been provided to outline the design approach. tom., jho�Pes 11.17. _The commercial area basins 2 & 3 drain toward the school site and is planned to be served by a storm sewer for 10 year storm flows. The sewer will serve the southwest portion of the school site and most of the school building roof drains. Basins 1, 2, 3, 4, plus school areas 61, B2, B3, B4, B5, and Basin area 5 all contribute to a south storm sewer that extends from the west of the school to the south detention pond. Basins 6 and 7 flow overland to the south pond. Basin 8 flows to an area inlet at the north end of the field, then by storm sewer to the south detention pond., Basin 9 flows to a combination curb'inlet at the southeast comer of the north student parking lot. Building B6 flows to the same inlet. These two flows are carried in a north storm sewer to the north detention pond. Areas 10, 11, 12, and 13 flow overland to the north detention pond. ' The south and north detention ponds have 24 inch pipe outlets to the outlet structure. The outlet structure will have 29.0 inch orifice plate to control maximum discharge to 44 cfs as required by the Basin Master Plan. Basin R flows to Red Mountain Drive inlet and will be connected to the outlet structure upstream of orifice plate. Flows from the outlet structure will discharge to the City's 36 inch South Tributary Storm Sewer to Fossil Creek Inlet Ditch. ' Ten year storm flows from buildings and parking area will be taken in storm sewers. Inlets were designed for the 10-yr runoff. The highest inlet has a top of curb elevation of 46,00 and the school floor elevation is 42.5 which provides a 3.5 foot freeboard during the 10-yr. storm event. A maximum 0.50 foot ponding depth was used at inlets to ensure that 10-yr runoff did not top the curb. Curb and area inlets were sized using SDDC Manual figure 5-2, 5-3 and the formulas developed in Appendix A. In an emergency situation where all of the inlets may become plugged, or during the 100- yr. runoff, ponding depth would rise to the top of curb then be directed to the detention ponds via overflow swales, channels, and parking lots adjacent to the inlets. The sump at Inlet, C1-1 is 1.0 feet deep before it overflows thru an overflow inlef, box to the channel south of school and between the school and commercial development. The overflow channel is proposed to be 20 foot wide with sloping sides and to be shared with ' the commercial area south of the school. The basins were delineated and runoff was calculated using the rational method. Table 1 summarizes the methodology and results of this analysis for 1.0 year event. ' The supporting calculations were done on a spreadsheet using the first 22 columns as. ' SDDC Manual Form on Figure 5-1. Additional form columns were added to allow data entry and calculation not provided for on the form. Calculation Notes, Procedures, and Reference Criteria for the spreadsheet is shown in Appendix B. Appendix C shows the supporting calculations for South Areaand inlets. Appendix D shows the supporting calculations for the building drains and South Storm Sewer to the South Detention Pond. ' 5 SIZING DETENTION PONDS The 100 year event SWMM analysis Series I was used to evaluate the effectiveness of the detention ponds on the school site. Runoff generated by Basins 301 and 311, school building roofs, was routed through Elements 301 and 311 without any attenuation of the peak flows. Detention Pond 306, parking storage, and Pond 313, athletic field storage, have 0.2 acre feet and 0.5 acre feet respectively. Pond 303 has 1.8 ac. ft. of storage above the irrigation pool overflow. The 6 inch irrigation pond overflow has a capacity of less than 0.6 cfs during the 100 year storm when the outlet is surcharged at the peak inflow is 53 cfs. The North and South Detention Ponds are connected to the control structure with a 24-inch pipe. The separation to the two ponds was necessitated by the elevation of the existing 21- inch sanitary sewerline which nuns west to east through the area required for the storm water detention facilities. The combination of these two ponds is Pond 213 as designated in the PPUDMP. SWMM version 4.05 with EXTRAN block was used to route flood waters through the two ponds and the outlet structure to the South Tributary Storm Sewer, Element 90. Results from EXTRAN showed that flows peaked at t= 1.5 hours and pond storage as follows: South Pond W.S. EL. North Pond W.S. EL. 22.65 with 5.0 AC. FT. 23.49 with 2_8 AC. FT. 7.8 AC. FT. ,Pond 213 has 7.8 ac. ft. of storage with 0.6 foot of.freeboard to the center of Red Mountain Drive. A variance for less than 1.0 foot freeboard is requested. Plugging eithercof the 24 inch outlet pipes from Pond 213 is improbable, but should this happen the pond,;would overflow Red Mountain Drive at Inlet R and flow down the concrete drainage swale and 20 ft. drainage easement provided in Dakota Ridge P.U.D. First Filing. SWMM Series I and SWMM version 4.05 with EXTRAN output files for 100 year event are included in Appendix M. UDSEWER input and output files for the South Tributary Stomf Sewer are included in Appendix N. DETENTION PONDS OUTLET CONTROL DEVICES Pond 213 outlet will discharge into the 36 inch South Tributary -Storm Sewer. Based upon a maximum allowable release rate of 44 cfs the 36 inch outlet pipe will be fitted with a 29.0 inch orifice plate. A rating curve for the developed condition (Series 1) was based upon a 29.0 inch orifice. The calculations for the 29.0 inch orifice and the rating curve are shown in Appendix K. 22 P L 1 I. ,I [] L 1 1 r _i? Pro w. - r'LeyJ f�Q' �-. lk SA jµo��ES ,o �T or�'3LD �ul�otNc� L �-ocATlor-t5 UNC SomK.&al Cermr Of S¢lion 39—+ �N. Y6lM l 4- I \y � —{T EDS, Of ASPKAIT PAVCNCNf \ i I — SECTION LINE \ " MORE PARKING LOT \ \ SAND SERVICE PADS E r� ( 4.5oPPES-rtFTURE CI-1 � Hu. CUTURE RUILDIKGS I '� X. AND ORWES L Ir 7.13 3 11O9SETOOIM RD. M1OWT. 10 5OU7M PARKWG LOT. ) � 0 0' /OUTN STUDENT (�1{/WO � PARKG a /� 1`� / O 'C 4.69 G STORM SCRCR- D 131 14_ZLd `Y bG-�hLTi dli P�'oN 05 -Fa�RT,v" of llr-w FT. H, S - _ j'-O2vM M�Llh1C. $ I�TELAIy 7 �Nc. ("ZcPor,T �si>J I ems i F`1 2 TABLE 3 ..DEVELOPED SITE:HYDROLOGY': "s: BASW AREA (AC) I C O (CFS) 16, c Q:(CFS) 1. 00. B1" 0.89 0.95 4.4 I 8.0 B2 I . 0.54 I 0.95 I 2.7 I 4.9 B3 0.53 I 0.95 I 2.6 4.8 1 3.54 I 0.55 I 8.2 I 16.1 B4 0.38 0.95 I 1.9 I 3.4 2 5.69 0.87 20.6 35.9 3 7.15 0.84 23.9 I 45.1 B5 2.22 0.95 10.0 20.0 4 5 4.69 I 168 0.90 0.45 18.5 3.0 41.3 I 6.5 6 3.32 0.37 2.7 I 5.7 7 5.09 0.68 17.9 I 30.7 8 9 1.68 17.43 0.45 0.65 3.0 27.9 I 6.5 46.8 B6 0.69 0.95 3.6 6.2 10 11.35 0.32 8.1. ( 16.8 11 4.38 0.25 2.0 4.4 12 8.46 0.25 4.2 8.7 13 4.59 0.45 5.9 I 11.0 R 5.99 0.64 7.8 I 17.1 C-IH 17/ 1 1 1 TABLE 7. SUMMARY OF STORM SEWER DESIGN LINE . TYPE: .. - DESCRIPTION..:._,,.:.• 10 YR . DESIGN- •: FLOW:.. .;...(�)._..... PIPE -.SLOPE` .-(,o).::;6n)(_':.($s)(2) PIPE DIAMEicR:.. PIPE FLOW `'VELOCITY FULL PIPE CAPAC.IY (Cfs) SOUTH SEWER ' Ht I LA i cPAL I Bldg. B-1 to MH-1 I 4.46 I 0.81 I 15 I 6.42 I 7.5 S1 I TRUNK I MH.1 to MH-2 I 4.37 I 0.60 I 15 I 5.69 I 6.5 H2 I LATERAL I Bldg. B-2 to MH-2 I 2.73 - I 1.34 I 12 5.55 I 5-4 S2 TIMH-2 to H-3 I 6.96I 0.60I 18 I 5.39I 10.8 S3 I TRUNK MH-3 to Inlet C',t I 6.67 I 0.60 18 I 6.33 I 10.8 H3 I LATERAL Bldg. 8-3 to Inlet CI-1 2:69 I 1.60 I 12 7.30 I 5.9 54 TRUNK I Inlet CI-1 to MH-3A &Inlet CI-2 I 19.89 I 0.61 I 24 828 I 24.4 H4 LATERAL Bldg. 8-4 to MH-3A 1 95 I 3 00 10 - 8.51 I 4.9 S5 TRUNK MH-3A to Inlet CI-3 41.18 I 0.59 30 9.58 41.7 S6 TRUNK Inlet CI-3 to MHO 61.82 I 0.43 36 8.63 I 57.6 H5 LATERAL Bldg. B-5 south to MH-4 226 I 2-36 I 10 8.09 I 4.4 HB I LATERAL Bldg. B:5 north to MH-4 I 8.05 I 0.50 18 6.12 I 9.7 S7 I TRUNK MH-4 to Inlet C" I 69.37 I 0.55 I 36 9.68 I 65.5 S8 I TRUNK Inlet CI-4 to MH-7 85.0 I 0.70 36 11.86 73-9 S9 I TRUNK MH-7 to MHO I 86.71 0.70 36 1210 i39 S10 TRUNK MH-8 to OUT 86.71 1.80 36 I 18.05 I 118.5 NORTH SEWER " H7 LATERAL Bldg. B-6 to Inlet CI-6 3.65 3.54 10 10.57 5.4 S71 TRUNK Inlet CI-6 to MH•9 2923 0.541 30 8.76 39.9 S12 TRUNK TRUNK MH-g to MK-10 2923 I MH-10 to OUTLET 292 I 3 0.541 I 0.541 I 30 I 30 8.i6. 8.75 I 39.9 I 39.9 S13 See Appendix F For Desicn of These Pipes. See Appendix G For Design Of These Pipes. (1) All pipe is smooth flow plastic with inside diameter greater than nominal pipe size. (2) Pipe velocity at normal depth when design flow is less than full pipe capacity. 4" ZELE:VAIJT -TO iP-O v. ouu-rueF OF PRaP(SsE-Q ER 5 CI -3 w[u. CONNECT TO ' r -ice �Fj--� N 17 COMPUTED SY Eli—y�"`OATE Meline & Ireton, Inc. SHEET NO. OF �+ Consulting Engineers CHECKED BY— / DATE / I FILE NO. O ry / Cori Ca111,,s_ cob aoo OJ T — r _ PROJECT NO. ' CALCULATIONS FOR: J vC R 1 O 1 2 3 4 3 6 717 29 3g 37 32 33 34 35 36 37 38 1 1 -8-9------ -- ----6 _19 - ---_22 - _-25 -28 2 _._._-..at--_-Q_.- 1 - -U - 10 - 12— z' r i I 1' v e a o +I 1 w I , . . 17 ' V 20 212,2 + 23 1 t 24 1 .- 25 26 ,- 27 1 1 I i f 1 I I ; I i 1 j s 11 •.j I LL i I ! ! I 1 j j 29 ' �Z�1%1Q7jZ�.�d� ' I •/ - /�� V. -- 33 34 35 1 37 I I { { 38 39 1 41 42 j-S� .Clro�� SF 6&7a pasfas ap : I .i. I it _cur —I--. --- 4 107�?I�nO OS'L£ '73 I t 1 43 - - - � � I 44 - • r -IF] n z3� �+ Meline & Irelan, Inc. COMPUTED Sr — P,A", Da:-c .SHEET NO. OF Consulling Engineers CNEC.tED 3r DA-.E FILE NO. ' :cn. C_�i..s. Cscrcco .�-�K�C �—Pf10d6E�T-N0�0 CALCULATIONS FOP: Q✓C r _, 0 1 2 3 4 5 6 7 8 9110 i t 2 2 6 21 3 3 34 z5 36 37 38' 1 Sr.�ro(-Faser-42.So-Co"mme+•� �.�o_riyl¢� �•r �a� Duct �owS _-/_{rrir,�ari_c�.•_--' 210 - FREE3DhROa(.7r �_(• - ..._ ..--_ -- - -'--'f.1����_� -- 4 ow 5-- 67.`6 10 12 --2L--ZO_0 -,4-. t• - . __' ._ �-3 to _t•_Zo_{-_ 3_SS --__3.G.2 17 18 SF� off¢ 81:¢7f65 20 22 i PLcL� L _ ' 23 • r�alrC7cYU —_'_ _ - i 23 31 ----• -. $� G.ODlo35 � ' - - �A53_CHANNBL..-belw¢-ex ScMea�_��a•3a.,_��°�.-$1�� , i 34o __-- _. .. _ ..—._ 35 --l.-Q�,ce�y-�,c�r's_�__A = .O._5�4.8 �- 0_._96_��k�. 2 f• / �6C"zZ�}G — --- / ' 37-'---'-- 38 Av�f • 71-=CfY.�ia o_0/6->< -23.3 is c.o¢a�-2�8-= O:o-2 �f — 40 - . i �_. -0 pz¢ o. Co 63S Al 42 43- 44 /'_IQ UDSTONE & ANDERSON, INC. ' Water Resources and Environmental Consultants 736 Whalers Way, Suite F-200 Fort Collins, Colorado 80525 (970) 226-0120 tMarch 27, 1995 ' Mr. Glen Schlueter City of Fort Collins Stormwater Utility ' 235 Mathews Street CO 80524 Fort Collins, Re: New Fort Collins High School Detention Pond Overtopping Analysis (LA Project No. COTST15.7) Dear Glen: Pursuant to a request by TST, Lidstone & Anderson, Inc. has completed an overtopping analysis for the new Fort Collins High School detention pond. This analysis was prompted by a need ' to determine the design discharge for the Dakota Ridge Phase 1 swale located between Monarch and Ute Courts, east of Red Mountain Drive. ' The analysis assumed that the detention pond's outlet pipe would be completely obstructed during the 100-year event. Consequently, outflows from the pond were assumed to occur only ' as overtopping of the curb along the east side of Red Mountain Drive. The Red Mountain Drive east curb profile was defined based on that shown in the Dakota Ridge Phase 1 utility plans [Parsons & Assoc., 1992]. The revised storage -discharge curve for the detention pond was ' incorporated into the Foothills Basin SWMM model. The results of this analysis indicates that the 100-year overtopping discharge for the Fort Collins High School detention pond would be 17 cfs. The documentation for this analysis, including the revised SWMM model, is attached. If you have any questions concerning this analysis or any of the enclosed documentation, please do not hesitate to contact us. Sincerely, LIDSTON ANDERSON, INC. Gre cry Senior Engineer GJK/tlt Attachment Branch Office: Box 27, Savery, Wyoming VM2 r -i G OWNER -PROJECT B y DATE PROJECT NO. n 305I5 CoT5-;E- a(i a l� � ^?C' FEATURE c" DATE SHEET OF 3IZ7I�f5 1 (fl J �1Piu)ron N6A/9e V)/Om Ig, o o v 0131g9 D 11.77 -4- eieualwo 011q,/4 5 1�1,44 g4.ao to la• I1 p,;3 15 ta• 85 0,4,4,;6 ao la•98 011141a7 as ee5.I450PI0P5wmM (9100 = 174 c f� V,00 : IM Ae_p�. !dstooS4 F! (ve(�)Po" dee*.= OJ5FJ. WHER—PROJECT Y DATE O. PROJECT H Pdae CGD 3/d3I45 EATURr'E r j� CHECKED BY DATE SHEEET OF t 54o(aoe I/I'v%Yh.4 �G""� (/� oq' ' lovlh =c✓o �i�rn CNS �xrQ�rl ;movE�- (rill,199� 61ev. ld/Coi 5orage ap 1,4q 1bg 3 08 , 5,45 A�1, ' as 775 !09 l:od a3 I-a9 •qqo a o3-,-s•Id = -7,757 ad L3a a�l i•egG /r547 wnv� no , rorvobme above arl,0 V% (II,a I qz %��+ (Ela•-a7%Ox/,S9G �9.G15) InumYin Fo,.ca,rq - 5wf h Pond (56000 ' Clev, A(Ch �n[iemlr�,a-rrr�al iroraaC ' Ig v o 0 I9 ' 134 o45 os ao 16&0 rill ' dd a•al� I ,qoo 5,40 � ay �•Uls arsra, �,a3 . ,1 EROSION CONTROL NOTES '.. - SEEDING CHART °r CONSTRUCTION SEQUENCE G ME TOWER SHOPPES P.U.O. COMMERICAL DEVELDPMENT SI1E LIES WIDIIN MC MODERATE - LEGEND df m RAINFALL ERODIBIWTY ZONE AND WITHIN ME MODERATE WIND ERODIBUTY ZONE. PER ,. .... m ar srcxo ww IcItich JI No r•d to ew b rtmwemrt or weesi on w xwe of We m+C ME CITY OF FORT GOWNS ZONE MAPS USING ME CITY OF FORT COLWM1S EROSION Tm Y vapblie+ ww/e.. dm•� oro:.y y.Jm.• Sholl f, w :M. x..•�u a.,ba qw .®a m.x,,. r ° ISRCP 'r R 1� rt 9 tory, y�R PROPOSED STORM CONTROL FOUND STANDARDS, ME PERFORMANCE STANDARD DURING PERFORMANCE STANDARD DA THIS 'tw'^Y rpawgr'w .o+an- SEWER u/ INLETS SITE WAS FOUND. TO BE J9.945, REWIREO.,THE ;ACIDAL-PERFORMANCE $IANBARU AHHIVEp �} Gt'b Pw'w] _ - - p` t y require ..o-" q 1 AT FOR MIS STE BY USING VARIES. EROSION.CONTROL MEASURES, IS 96.22%. THEREFORE e= cCO m weir botp1u.. MgwtN° Rate - - - E%ISDNG STORM DRAIN Rxnss aLt °9U7 COMPLYING AM ME CITY OF FCAT:LOWNS, REWIREMENTS p - •w t tr•lr'• *+.' Y` Nmn° E ) an bl inn i5 �43 .t m o e03,31 by °f W c°.b. em (1Aeu u mnmt•) Y PROPOSED G C)NTOUR (Y IN @RVAL) rn r op lots u c u 1 v a e s gv6 l' am THE EROSION CONTROL PUN DICTATES MAT'AF1ER OVERLOi GRADING HAS BEEN COMPLETED, m, ur N•° at " 1 ALL DISCUSSED AREAS, NOYLCCAMD WIHIN 'A BUILDING PAD, SIDE WAI H, OR ROADWAY/ x uwm so w w •bo...fa eAm AN xr m.wao. L.w -e at r SbX el w IWn waI SS CONTOUR - PARKING LOT AREA'S4ALL HAVE'A'IEMPIXiARY VEGETATION SEED AFPLIf U PER IIIE'. w +mr n mm a nqm. w.. ne°°q am mtrn w�• nn Fnn a mn.e _ trNi SPECIFICATIONS GIVEN ON ME. DRAINAGE AND EROSION CONTROL. PLAN (INCLUDED IN ME ••_"^ wwm 10 #° "o.yra°e mMm.,°'"dwa. rename Q BASIN SDE51GNAnON q' 1 x 1 If :.gnitm N u•ea npou, fort qr may M rd'J na° wen la tnwgF SglwNv ]o- e ole BACK POCKET I MIS REPORTT AFTER TONS PER A HAT MINIMUM. MULCH SHALL L APPLIED - 4.6UC r t, r OVER ME SLED IN ME AMOUNT OF2 iIXiS"PS ACRE, MINIMUM.. ME MULCH SHALL HE xn w vm. wen e. rnw.e I° a en. a BASIN: AREA C TI °m , ADEQUATELY ANCHORS TACKED. OR CRIMPED ONTO DIE SOIL PER ME METHODS SHOWN o too, nn Nul ro parting emit rw I m m m • w by BASIN,'BWNDARY ON ME DRAINAGE AND EROSION CONTROL PLAN.. THUS INVOLVES AN(AREA TOTALL114G Mejn mpt meW gmenm. • l c4 1 APPROAMATELY 2.09 ACRES : `" ° -w R u. o.Qe SULVOTUTALj nrdtl `aa 4mmwNw..: - (c) A vYl •nImGo u u �br n - I DESIGN POINT �_." IS that Fiat AFTER ME INSTALLATION OF UnUTIES, ALL AREAS ON WHICH MERE WILL BE PA'✓EMENt. pi be IQ -qu e n 1 CONCRETE,.OR P BUILDING SHALL HAVE q GRAVEL MULCH/BASF. CWflSF. APPLILII AT 135 AlI'EpwM4 rtYvcpepY/mWR - -- FLOW DIREC110N t 1i` TONS PER ACRE THIS MEASURE INVOLVES AN AREA TOTALLING 8.26 ACRES UesYS CRbp pupFS MR wrvtwb.a mach.xmq h"J °.. IN, bn SCALE 1'=50'. - 5 - • '.' . t: mstfut •. • a r r s HP. HIGH POINTCOLy 1en - bee Cod cool ateod No theth mtw.'Nen - L.P.-LOW PONT uon 1/ .Y uwa°µe AFTER MEl CONCRETE OF CURB JNLEI5 AND SIDEWALK LCOARS GRAVEL SHALL BE - m A O a• veil r .,am b me - 1 FILTERS G T CONCRETE BLOCKS 1 UTILITY. PLANS 111OdRSE GRAVEL Sidi )_' •e �1 ` n;% ; b k " ; /2" ARE SCREEN AND C ACCORDING TO ME" RETAIL SHEET OF ME U IS INCI VUFS nTF SAME AREA III No INN bay mrl w xa• a ocaax rryil - - .t AS ABOVE TOTALED B28 ACRES t Yof L y v {j�,]Rjr7 1p�/ / 1 by /y� .AVERAGE STREET SLOPE We =S .. _ I• "" Fx6Te'CURB•INLET (CI 2) xa x>+ I [�'BNAVAIII "I R�c `i f1.11'l1aF,�A1`mismi�lf, Go- C/ ♦� PROPOSED BAL[FOLT BARPIER SOON w SS PAN O. a,]e„ t P f,' 1 bili Seed Lit ♦♦♦P % LIT Limi? Ii — — - w - EAST. I ANDLE IS sl �'IF f11� II ' - -- --'• • I I EASlIN6 O GRAVEL INLET FILTER 1 U - STRAW BALE CI�RBE55E0 M < rti_� 4 +E sbxr no �— 26 LK 21M CUSS III RCP r IL 1 , / _ SILT SAPPIER 1 - ,° °`� 014 �„� -. t( 1 r a+i. No IS dd .. 4.of •-_ I i idr '--- �, L la _ - L'-. PERMIT NC'YES 1 Z' EVE 'R' 4 S ' �i 1• �+ _I63'LF OF a ' NCE CURB INLET FOR . a 'TS- ^A Fla 3 5 b'1 0 uN S WM 1 p OLIMI ON PREVENTION TT T 1 - • ... Ef JO 1F. SICHu • m — I �'� Ns -. E ti IP M IM°elm a °o ell m 5 ��E Iw. fPl Wn lN, e s n TQbW (T .•. a// --- -.� - 1-r�--`. 'i 14 FE%ISTINO TT I D m ••e ar fl . _ .� .x:_ h _�A :I _ - � , i� CURB INLET Pb m pccl l p NM„ Idl b. Mlnd K al/ ed x4 lIl'e IrdbAay ' J2 j 1 J N eeWM Oy I _ # 9 IIIY MdaM po.e.by AN b at h C. aides OF ch the do ci to -._ •_ .__a_. mahottllglgncal�Agb •U tlr meWClm Rallmd oCalo. r°IdlYaull bllalForRlla'G Yi4�n pbdl.Icwto14'a �rY li _R ASH fNDDPE'� 1° ozs a m L, II wun lne ugewm •e c I w t a et < awla R4• +9ll i, R rpl EIeeW111Y 3 d 4M of Wnd ErdbX1Y' - 1 6 dNdl Sea 'Pl 1 1 6 MI' :q d I a 'y E l' CONCRETE .REMOVE PLUG Z a lbA alY 'r ! W a eM WIK.Ib:'. e q pl A e y 1 }n a R qA � [„ WL T •Q a { ' r /( ni TO IN9 Y(e M of W W°•YiatoY fill Ud n t•° IM gitl lF t `� Imw vem MI b b I•a to bol •be d r°Mdl., the 1 Nb t b 1 1 .: , YB S10RM \ EI08 T. 51UB IT .}ids W mlem pP T - a b d loMen i I�n�lr. fqt 100 cp y1, of d ea f WOO M 4 d d w l f,. I . J.: 1.o T• N. wobNr Pbl.'TIIAl AIkn 1he u1M 1emmN•1•d leeatof �ie v°IF .41 IIA III. IluB121111LC. NO 101 NlTle eNelRlwANndrel NAQ bad h'$ L. I. 1 A r r— - r each 6 Tx ro EXISTING I - 0 11 MI t l l t 1 eNNwgeE s o ER coNmas S - MANHIXE 16 51AC " f -,q '. u Iq Tim [ Wlp n p 1 .,eyd e° Noc11 e Nito M° ;Wymn we1 I cl I t e I' 2 O..I 11 n ICI 51 �N IeFI It �tlX �b .L al y IF each' TIT l aJ ab a lM9 MI Tell I.kt 1 0 .]6AC 3 ql° it F g ne.k xl l elm .n. a °l a la l < reel q s renbl x d'yl 9 °mqu. a ahl b a'bb! �i II u..f a. orap. n 1. c a p q ar• a e l 1 P' ! IM Wy I1 e ea : ,°.4 r 82AC dudlY,f m Co b.E v e sle I ^ °I' '� : ! N ryeuq6 'ae ea b 1 0 6 1 b .: ° as R L� • bXNpd1:B 9 N 9 Y l m L _ I'I{ GY R � 'S S fV TOM O MAINTENANCE NCE. I el � 1j e � �0 �II 'al Ikn ab% rolVuU pp 1� 1 yf a vxlMe' Mrlal . 1. 'p: ecl a I novae stood b e l If l M P, Y . L _ _ x a ETA ■ -x'a'4 "i gmn'F utlemlma• n r l t 1,, Tip J sr orals- @Yo Y M s i s �elllmb`ail°w mps n u'",T 4 s "X ol; 042AC SroEWAuc 4945 yin v� s• caossvANo o.eE S Y 2 71 , o�f • 11 y 2 T 1 J �.. ..+ unn ILLI, o 4940 W - *..':i`. E.-39illy 1 .60: m p A NI:.. '-�- _ .' - Ip 4935 cuLVERr mrvc+ox .Y' �' •t Y _ C� I DEPTH os o.o{I .rpn .. xON ,. °v o 4930 ❑ , 1' Xy _-;yA 1 3 3 1%2 LRANS r:+ Ti 4LRD gN ,' 1• Cfi0S5PAN t _... - = lll- "-' L by `f3 H`54'N ' i; _LNo A Ad I I 1 m I_,j IOC YR. OVERFLOW CHANNEL PROFILE C _s HOC dy RI Go L 11 1; Of b ,®�t1 1 nb� ®rrt7111� ® t 11 - y U s e, _. ID City I Olga •qn -HIGH SCHOOL EXISTING E CROSSED 494 $a FF. CttU'fRl•I•Y PLAN APPROVAL[. d W . EAST HORSETOOTH ROAD m T- coMia BLDG. gppppVEp_ Wr of Colorado L EXISTING GRADE CHECKED BY I 1 Meter t luleeeter UWlty _ _- - .CALL MODIFICATION / CENTER OF COLORADO No 1-587 ° 34-700 34-6700 " BN 8NDAYS . DEVELOPED SITE HIDROLOGY DESIGN POINT BASIN AREA (IS) C (Ca) - (ADS) 1 1 1 6.57 0J4 209 501 2 2 176 085 I69 33.8 3 1,2.J 095 1 4 0.42 0.42 U.95 2.03 2.03 399 3.65 dlpo.IN OB4• CHECKED BYE Qlw' 5245 cIN or 0001 j /Iul'-6' 0 2'-0 10�= Itl 11 3 COMA INTO ! S OBOE CHECKED BY EAST. STAB �.f. 01�+3Jf 6990' a : Perks A Rxmi 100 YR. OVERFLOI CHANNEL A 004 eDS£9aADD Los CHECKED BY 6 CHECKED BY: a PEC KWG�SAM DregwT pEvcrlEo cNEceEo MAyls9s Qee-ol5 :APPRpvF➢ pA1E "' PRVALI rvU, ��� Engineering Consultants fig = M°Mu� Slmt Dm v, N!a er, W y 9.fY [ Inc. xwxL.N..daW.xmS=F nrrolx:famxr bf /ree-mx wT/eye-n6xa TOWER SHOPPES P.U.D. PORT COLLINS, COLORADO '. DRAINAGE &EROSION ;;. � CONTROL PLAN "HEATS - '+ 8 + NO, BY. DAIS REVISION -0ESCRIPTION IT 0 v'AA I 1 ' APPENDIX D ' EROSION CONTROL CALCULATIONS 11 1 Interwest Consulting Group RAINFALL PERFORMANCE STANDARD EVALUATION PROJECT: Sonic Drive In - Lot 4 Tower Sboppes P.U.D. STANDARD FORM A COMPLETED BY: Jzung DATE: 12-Nov-05 DEVELOPED ERODIBILM Aeb LA Ssb Ai - Li Ai•Si Lb Sb PS SUBBASWO) TAME (AC) (M C - Sonic Lot 4 MODERATE 076 380 2.0 288.8 1 5 WO Pond area 0.66 500 1.5 332.2 1.0 Total 1.42 610.97 2.11 436 1.8 80.4% Asb = Sub -basin area Lsb = Sub -basin flow path length Ssb = Sub -basin slope Lb = Average flow path length = sum(Ai Li)/sum(Ai) Sb = Average slope = sum(Ai Si)/Sum (Ai) PS is taken from Table 8-a (Table 5.1, Erosion Control Reference Manual) by interpolation. An Erosion Control Plan will be developed to contain PS% of the rainfall sedimentation that would normally flow off a bare ground site during a 10-year, or less, precipitation event. Erosion.xls PAGE 23 H C O W W 6 i C O W C c c to to to W C g q co p\ G I C C I C C G O C C c c 6 C LI: L[1 L1 11 LC: lf") O O O W W W C C W W C C1 G� CT O'C1 �nl O+O�rn GI COC g C p 4 C C q q q C W C C O q n qC W CT 01 C1 [T Ot G10101OO1 P•G1 CT C%m 01 c c c c c c c c c c c c c c c c c c c c g q W W W W C W W W W W W W W W W W W W C M CLCI lO LC ll7�nnn nnnnnnnnn W W g W W W ; q q W Q W W W g W W ccC W WOW W WW q W .... W W W W i g N M C l P) I n 117 t O t 0 l O t C t O t 0 1� n n n n n n n n n W W W i M c c c c c c c c c c c c c c c c c c c c c c c c c 1 g W C co co W co co q co W q q q q'W W co O co C W g W W W; tO O N M c C• i[Y t0 tl7 Cl') t0 l']_� tC tO t0-tC tC t0 tO n n l� n n n ; M c c c c c c c c c c c c c c c c c c c c c c c c c 1 co W co cccog q W O W W co q co W co co co co W co W W co NMMcccc lf)t0 Cn 11')t!] Lf tl: L' tC: l9 tC tC t0 t0 tOn i M M c c c c c c c c c c c c c c c c c c c c c c c c l co co co co co cc cc CG W co cc co co co cc co C W co cog co co co C t0 co O ^.--INN MMM M ccc c c c cclr=11i 1!')lfi t0 t0 ; M M M c c C c c c c c c C c c c c c c C c c c c c c l coC W.W W W G C cc coW cc ccC co cc co co W coW OG.r e-+.--�NNNNNM MMMMccccd: i N M M (` M M C' G' c e t c c c c v c c c c c c c c c c c 1 W g W W W q O q W q W C q O q W W O q W C q q W W W i y W r I M c 1 S f 10 O n n n W W W W C CO O\ C C O O O' i g q W W W W q W W W W W W W W O W C q W W W O W W W i tO tCf qG.--IN Mc c1A u'f u)tD t0 t0 t0 tG nnnnq co qCT. CT ; .- +NNMMMMMMMM M MMMM MM MMMm Mmmm I co co C coW W O W W W q W q q W W W W W W W O W W W W .r.-+tif n W CC.-•�NNMMMCC'ccctn la7 u'1%010\Onn ; N N M M M M M M M M M M C) M M M M M M M M M M I C O CCC coC ccC co co coq co co co co W W ccq GoC"j co co coW i MN to co Ct O NN NMM M ccccc cLo tf!Lo 1A tC t0 t0 t0 ,1 G. r N N N N N N C V N N O C C W Coco 11 Y 11' f fi N M c t 10 t 0 n n n W g W O t C T 01 C T C T C T C O O O O O i CT C 0 ..+ .--� ^ ti ."i .--I '-1 .--i ^ '"•i ^. ^ ^ .+ .--I N N N N N N 1 c tl'f O M "7 t0 O W CTO C O .-I .--I •--� .--I N N N N M M M M M'M ; co m 0 0 0 0 G 0 0 .--I ti .--r r+ .-..ti ." r" .•I .--i r+ ^ .-t r. ""i ^ ^ I W NCB-•. clnnn qCT CT 00.•+. ... . . . . . . . . . . I %0 co co CT cn m m0\ CT m ON CD O CD CD O CD G O C C C O CDO I n n n n n n n n n n n g W W W W W W W W W W W W W W i t0 M CD n m O.-+NMM cctn ll'1 to tl)t0 t0 t0 tOnna0 t0 t0 1 c to n n n n W W W W W g W q W W W W W W W W W W W W I n n n n n n n n n n n n n n n n n n n n n n n n n n mCD ctD n co cc nntc tC tD tOc c M CINN CT tO c.+CT lO O N N N N N N N N N N N N N N N N N C N11; S 1 O O O C O O O O O G O CD C CD 0 0 0 0 0 0 0 I.O C7 F- I O C C O O C O O O O O CD O O O CDO O O O O CDC G n O O m C I. C' 1 0 N I W W v I T e-1 I--� .•+ .--� e-� rl .+ .-•I I --I rl N M � c W 1 J 1 I 11 -� TABLE 5.1 b - 2-- Interwest Consulting Group . EFFECTIVENESS CALCULATIONS PROJECT: Sonic Drive In - Lot 4 Tower Shoppes P.U.D. STANDARD FORM B COMPLETED BY: JZBng DATE: 12-Nov-05 EROSION CONTROL C-FACTOR P-FACTOR METHOD VALUE VALUE COMMENT BARE SOIL 1.00 1.00 SMOOTH CONDITION ROUGHENED GROUND 1.00 0.90 - - ROADS/WALKS 0.01 1.00 - GRAVEL FILTERS 1.00 0.80 PLACED AT INLETS SILT FENCE 1.00 0.50 . SEDIMENT TRAP - 1.00 0.50 STRAW MULCH (S = 1-501.) 0.06 1.00 FROM TABLE 8B STRAW BARRIERS 1.00 0.80 EFF = (I-C-P)• 100 MAJOR - SUB - BASIN AREA EROSION CONTROL METHODS ' BASIN BASIN (Ac) C 0.76 ROADS/WALKS 0.54 Ac. - ROUGHENED OR. 0.06 Ac. - STRAW/MULCH 0.16 Ac: GRAVEL FILTER- NET C-FACTOR 0.10 NET P-FACTOR 0.79 - EFF=(I-C*P)*100=. _ . 92.1% Limits of Construction 0.66 ROADS/WALKS 0.00 At for WQ Pond ROUGHENED GR. 0.00 Ac. STRAW/MULCH - 0.66 Ac. GRAVEL FILTER NET C-FACTOR 0.06 - NET P-FACTOR 0.80 EFF=(1L'P)*I00= TOTAL AREA = 1.42 ac TOTAL EFF = 93.6°/a (£ (basin area * eft) / total area REQUIRED PS = 80.4% Since 93.6% > 80.4%, the proposed plan is o.k. EROSION �) -3 CONSTRUCTION SEQUENCE Project: Sonic Drive -In - Tower Shoppes P.U.D. Lot 4 Date: November 18, 2005 ' Indicate with bar line when constructions will occurr and when BMP's will be installed/removed in relation to the construction phase CONSTRUCTION PHASE (2005-2006) JAN FEB MAR APR MAY JUN JUL AUG SEPT OCT NOV DEC Grading (Include Offsite) _ _ 0A ` Overlot Detention/WQ Ponds AA Swales, Drainageways, Streams Ditches Pipeline Installation (Include Offsite) Water Sanitary Sewer ow MR ft" Stormwater WIN V-WM., Concrete Installation (Include Offsite) Area Inlets Curb Inlets Pond Outlet Structures Curb and Gutter Box Culverts, Bridges Street Installation (Include Offsite) Gradiing/Base Pavement Miscellaneous (Include Offsite)" Drop Structures Other (List) BEST MANAGEMENT PRACTICES Structural Silt Fence Barriers -- ....-_... _. _. Contour Furrows (Ripping/Disking) Sediment Trap/Filter w Vehicle Tracking Pads MAN .m ,:� Flow Barriers (Bales, Wattles, Etc) Inlet Filter Sand Bags Bare Soil Preparation v Terracing Stream Flow Diversion Rip Rap Other (List) Vegetative Temporary Seed Planting Mulching/Sealant oft M5 WA Permanent Seed Planting so aw, Sod Installation Nettings/Blankets/Mats Other (List) " 1 1 1 1 1 1 1 1 1 SONIC DRIVE-IN - LOT 4 TOWER SHOPPES P.U.D. EROSION CONTROL COST ESTIMATE JOB NO. 1025-021-00 COMPLETED BY: JPZ I;RUJIUN L.,UIN ITEM L KUL, DESCRIPTION UNITS UNIT COST QUANTITY TOTAL COST 1 TEMPORARY SEED & MULCH ACRE $ 775.00 0.8 $ 636.88 2 SILT FENCE LF $ 3.00 350 $ 1,050.00 3 GRAVEL CONSTRUCTION ENTRANCE EACH $ 500.00 1 $ 500.00 4 INLET PROTECTION EACH $ 250.00 0 $ 5 STRAW BALES LF $ 3.25 3 $ 9.75 6 SEDIMENT TRAP EACH $ 500.00 0 $ COST $ 2,196.63 L.I1 [ f(LLJGG ITEM VLIVII LVJi cva� av+.w ... DESCRIPTION UNITS UNIT COST[QUANTITY TOTAL COST 1 RESEED/MULCH ACRE $ 775.00 1 1.4 $ 1,100.50 COST 1 D-5- NUTEb I. ALL DISTURBED AREAS SHALL BE RESEEDED AND MULCHEDAND/OR SODDED PERTHE LATESTAPPR YIEO LANDSCAPE PLANS BY ALLERUNGLE. 1 I II �yJJI I 2.EKUNDERGROUNDINSTALLATIONSSHOVVN RINDICATEDORDINFORMATNJN AVAILABLE E TOTHE ENGINEER. THE ENGINEER DOES NOT GUAETEACCURACYOSUCHINFORMATION. ERMCER.POWER, N�_ GAS,STORMDRAINSANRARERPHONE,MYNOTBSTRAIGHT LINES OR AS INDICATED ONTHEPLANS. THECONTRACTOR py1% ENIM•Iw \ 30 15 O 30 BOSHALLCALLALL UTILRY COMPANIES BEFORE EKCAVAT!ON FOREKCICi LOCATIONS. yylpy/Eµiry 3.ALLSTORM PIPE TO BE REINFORCED CONCRETE PIPE DROP) CLASS III UNLESS OTHERWISE NOTED. V,T `� I SCALE: 1 =30 4, CONTECH"PYRAMAT"TO BE INSTALLED PER MANUFACTURER'S SPECIFICATIONS. CONTRACTORSHALLNORFYCONTECHSOTHAT ONE OFTHEIR REPRESENTATIVES IS ON 57E TO ENSURE PROPER INSTALLATION. uiNs 5. SEE SHEET 2OF7 FOR STANDARD EROSION AND SEDIMENT CONTROL NOTES. SEESHEETI OF7FORTHELEGEND. SjTjNy IXFORTCOOOL _ �Jf- '0�8 II HIGH ORT I coOOL ' \ I 6N Gix 1ER] llWf E]£B01Idl Y- A A A CIX A9YNL r AwW 4 t T /WAffl (m/ i 10 FX STIXIM) -wJsu ,`. _ sim � J `\\\ E;i millonic o (C E umN ]t 3 1�=,�4�'_'i-°_-—'_-"_' _�.- n IX .'s wwvmT. s"n' TM' II I IN s u �'+-r '+---: __ �. - _ ________ _- 7Wf•, a _ �a m s.0 wo III--Exe-JI r - - -- _ EX9AYE) `� w d W Y EX __ _ ____ ri pip- _ _ ___ _ _ — ._`__� -I ' $ u.E .uv ¢E 397�� __ _ 1 Ems, s rouseu FA'/AW'UE. AIO aE s - 4 _-_ EM iOM - \ y ��- —� +.■ _ ___t 5 _ S — n. v- say Xm4W7.25 I� \ ■ \ ODIN P IN�iT DR ■ I 4938 L 4935 o-w — — — — — wv zaa iIS�!!ettl'19, A T■ v aaFaol[n EWn ��193Z Ie' sv \ L__--____�_ — —4939mom mile_ _ —n ---- I11 Am mom oppop MENWA —mroosm o.E dwcwcr er \ \ I /1 (Yd SB'MI.IF DOLI.MgT) MD11M30' \ \ LOIIRACRR $NNL MNNTNN / / / / I jME WNItt C -37W.1q WNI WM \ PDIUVE DRAIN) IN Ofl.TW - AMn•3 SMMM IS' INV 0JT-K3D.02 o IX gIN1U4E SVNE / / I / ItI WNIR.CRw Al ALL MDVEX 1BPOIMY S6MIDITOIEE (SfE DUAL SHUT ] [f ]) '` I q 1 T\ / / / 1 TNM w CfT11KK! Patio I1SylE ] ONLY, ` \� / wTs Do' caxsMnON (mm.) 1 III l / , LOT L j If AREATA. FA . 0..0 U..PES l'I ♦ TOWER SHOPSP. D. / / / it / DRAINAGE SUMMARY TABLE if / imp ("IN "No WIN NA MIRMANS i k 2 1 ro v I as Im 71 pliftpippimp •cwU.,To.awm wem aw.ro..msA.lo.co.oa RNP.W r,W TeW.T anoPP.. PUOI,WDSI \7 � ," // � \ / / ' / / •waw..Lm2.s..m....I n.Nala� TOWERSNOPSP.U.D. / / �4 \< I � I — I— 24 dFAw A£ \ "MIND 'UE. (PFR SPMA,F DIXlIIENlI \ I LOT 3 TOWERSHOPSP.U.D. (EX MCOONALD'5 RESTAURANT) TOP OF BEAM 4938.5 O(10O) m 53 CFS SPILL ELEV 4938.0 WOCV EIEV op 49375 a SPILLWAY DETAIL JAW' UE. ! AC — — �-4 W—EM9'-W �W \ \ 1� �YLA--amt �Wl� `F�= 1 it � I I 78G I I 0 law' uE OhIpsw\ \ J LOT4 (PROPOSED SONIC DRIVE-IN RESTA URANTD IXfMMHRANI- ASIDHI _—_'F_______________________ ( I I I I I I LII I Er yMTMyrMVYx WhwI !*/-W.IAIato E-TABS IC - ------T----- I IX AW' UE *.AV. I 8—! L—r------ I I I ----- �,\\ ___ ____. 5%CIC __A E)(f@I]ED L£f@fflW BA91p ILLSxLn4. wt1A��W 94d AMHc 0 �omml �_©mm mom WWMCWroaaFGre Vtlurs RglM. nn w,ro.Iromw..va�.�.Rwae. nro n AMD. P I wa {m OTY OF FORT DOWNS. COLORADO UTILITY PLAN APPROVAL 13�:Ilffl.9b aTY daNRA - CHECKED BY: WA,T2A Y WoFTVAW URITY CHECKED BY: STMMWA. UWuv CHECKED BY: N4'YPIPr PMNs A ICcnGnpl 'w""'IWP'�^' CHECKED BY: moot daxBn CHECKED BY: u _ Ell i III U Q U) WFE N 0) F0 .0O 9 �1 ZNOLD 0 MNb 6 D j0)I. Qwm u oLL a In o w(0 F q D a Z u) moo WIL a w? f =fix tpU) Iil I u U W OFo z a O J m 2 m mq PROD. NO. 10254 50F7 :ice — a —