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HomeMy WebLinkAboutDrainage Reports - 05/27/1997{. Rn a� Af Dad 11 } SHEAR ENGINEERING CORPORATION Final Drainage and Erosion Control Report for 1 pL9 ko �U� h MAY 1 51997 The Howes Street Hideaways L_ Previously known as Lots 12-14, Block 105, Harrison's Addition Fort Collins, Colorado Prepared for: RAYLINE DEVELOPMENT CORPORATION 4712 Westbury Drive Ft. Collins, Colorado 80526 Phone: (970) 204-0306 Prepared by: SHEAR ENGINEERING CORPORATION Project No: 1536-08-97 DATE: May, 1997 4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX (970) 282-0311 PAGE 1 Project No 1536-08-97 Final Drainage and Erosion Control Report I. GENERAL LOCATION AND DESCRIPTION: A. Location 1. The project site is located in the Northeast One Quarter (1/4) of Section 14, UN, Range 69 West of the 6th P.M., Ft. Collins, Colorado. The site is Lots 12-14, Block 105, Harrison's Addition. 2. More specifically; the project site is located between West Mulberry and Myrtle streets in the middle of the westernmost lots of Block 105 (See Vicinity Map). 3. The site is a part of Old Town Fort Collins and is developed. The proposed duplexes will be constructed along the existing alley at the rear of existing lots. B. Description of Property 1. There are currently 3 single family residences on these lots. The existing houses front on South Howes. 2. The site area is approximately 0.63 acres. 3. Development of the site will consist of the construction of 3 duplexes at the rear of existing lots along the alley. 4. A gravel alley borders the site on the east side. This alley will be paved from the southern property line of the recently completed Mulberry Green project along the entire frontage the site in accordance with the requirements of the City of Fort Collins. a. The alley will be concrete paved and provided with an inverted crown section to assist in the conveyance of stormwater to West Mulberry Street. 5. There are no major drainageways located on or within 150' feet the project site. See Drainage and Erosion Control Plan in stuffer envelope. U. DRAINAGE BASINS AND SUB -BASINS: A. Major Basin Description 1. The site is situated within the Old Town Drainage Basin as designated on the City of Fort Collins Stormwater Basin Map. a. There are no drainage fees associated with the Old Town Basin. 2. The approximate limits of ponding in the area of Mason and Mulberry are shown on fig 5.1 of the Old Town Report in appendix IV and the ponding exhibit on the Drainage and Erosion Control plan PAGE 2 Project No. 1536-08-97 Final Drainage and Erosion Control Report II. DRAINAGE BASINS AND SUB -BASINS: A. Major Basin Description (continued) 3. Stormwater from the site drains to conveyance element 205 as delineated on figure 4.1 of the Old Town Master Drainage Basin Plan. a. According to the Old Town Master Drainage Basin Plan, stormwater flows in conveyance element 205 are split at the intersection of Mason Street and Mulberry Street. b. Some of the flows are conveyed east in the existing storm sewer while others are conveyed north on Mason when the storm sewer capacity is reached. B. Sub -Basin Description The site is extremely flat. We surveyed the property to determine if there was a defined flow path. Slopes across the site range from 0.5% to 0.70% from west to east and from south to north. The site slopes from the back of walk along South Howes to the east between all the existing houses. At the rear of the existing houses the site begins to slope to the north towards lot 11. Runoff then flows in a northeasterly direction across lot 11 and 10 to the alley. There is a high point approximately 60 feet west of the alley.which breaks the site into two sub -basins which we have designated Ae and Aw. a. Existing spot elevations are shown on the grading plan. 2. Development of the site will increase the area in basin Ae because this. area will be developed and therefore it is deemed better to convey as much of of the runoff from sub -basin Ae to the alley. The area of sub -basin Ae before development is approximately 10,150 sf. (0.23 acres). The area of sub -basin Ae after development is 13,775 sf. (0.32 acres). The area of sub -basin Aw before development is approximately 17,860 sf (0.41 acres). The area of sub -basin Aw after development is 13,775 sf. (0.32 acres). III. DRAINAGE AND EROSION CONTROL DESIGN CRITERIA: A. Regulations 1. All storm drainage design criteria from the City of Fort Collins Drainage Criteria Manual was considered. 2. Recommendations made in the Old Town Master Drainage Basin Plan prepared by Resource Consultants & Engineers, Inc. were also considered. a. Flood elevations noted in the Old Town Master Drainage Basin Plan were utilized to establish the minimum allowable Finished Floor Elevations of the proposed single family residences. PAGE 3 Project No. 1536-08-97 Final Drainage and Erosion Control Report M. DRAINAGE AND EROSION CONTROL DESIGN CRITERIA: A. Regulations (continued) 3. All erosion control design criteria from the City of Fort Collins Erosion Control Reference Manual was considered. B. Development Criteria Reference and Constraints 1. All grading design must match the existing elevations at the property line due to fully developed properties adjacent to the site. Retaining walls are expected along the north and south property lines. 2. The nearby intersection of Mason Street and West Mulberry Street is subject to flooding due to insufficient capacity of the existing storm sewer. a. According to the Old Town Master Drainage Basin Plan, the 100-year flood elevation on Mulberry Street in the area of Howes Street Hideaways is approximately 4993.5 feet. Refer to figure 5.6 in the Old Town Master Drainage Basin Plan attached in Appendix IV. b. The lowest existing elevation on the site based on survey information is 4993.93 feet. 3. Minimum Allowable finished floor elevations shall be 4995.0 feet in order to provided the minimum 1.5 feet separation above the defined 100-year water surface elevation. A note stating this is provided on the Master Grading, and the Drainage and Erosion Control Plan. 4. Detention is required if the imperviousness of the site exceeds seventy percent (70.0%). This is in accordance with the assumptions of the Stormwater Management Model (SWMM) for subcatchment 205 in the Old Town Basin. C. Hydrological Criteria 1. The Rational Method (Q = CIA) was used to determine the pre -developed and/or post development peak flows for the 2, 10 and 100-year storm events at critical points. D. Hydraulic Criteria 1. Storm sewer and drainage channel capacities were based on the Mannings Equation. The Mannings coefficients are as suggested by the City of Fort Collins Storm Drainage Criteria Manual. PAGE 4 Project No. 1536-08-97 Final Drainage and Erosion Control Report IV. DRAINAGE FACILITY DESIGN: A. General Concept 1. Stormwater is conveyed to West Mulberry Street by a combination of overland and gutter flow. 2. The alley will be graded with an inverted crown to facilitate conveyance of stormwater into Mulberry West Street. 3. Detention is not required because the imperviousness of the developed site does not exceed 70%. B. Specific Details The following table summarizes the land cover and the appropriate percent imperviousness on the existing site. Area Impervious Runoff Coefficient (acres) % "C" Lawn ---------- 0.53 ------------- 0.00 ---------------------- 0.20 Roof 0.09 100.00 0.95 Concrete 0.01 100.00 0.95 Total 0.63 The imperviousness of the existing site is 15.87 %. This does not include the alley or the 1/2 ROW which front on the property. The imperviousness percentages are taken from Table 3-1 in the Urban Storm Drainage Criteria Manual - Volume 1. The Runoff Coefficient is taken from the City of Fort Collins Drainage Criteria Manual.. 2. The following table summarizes the land cover and the appropriate imperviousness on the developed site: Area Impervious Runoff Coefficient (acres) % "C" Lawn ----------- 0.33 --------------- 0.00 ---------------------- 0.20 Roof 0.22 100.00 0.95 Concrete 0.02 100.00 0.95 Asphalt 0.06 100.00 0.95 Total 0.63 The resultant imperviousness of the developed site is 47.62%. This does not include the alley or the 1/2 ROW which front on the property. The imperviousness percentages are taken from Table 3-1 in the Urban Storm Drainage Criteria Manual - Volume 1. The Runoff Coefficient is taken from the City of Fort Collins Drainage Criteria Manual. PAGE 5 Project No. 1536-08-97 Final Drainage and Erosion Control Report IN. DRAINAGE FACILITY DESIGN: B. Specific Details 3. The proposed development results in an increase from 15.87% impervious to 47.62% impervious. Detention is not required because the site is less than 70% impervious. 4. The overall imperviousness of the developed site, the alley and the 1/2 ROW of Howes Street is 57.47 percent. 5. There is an existing retaining wall / sidewalk along the south property line which the proposed grading matches into. 6. The proposed grading at the rear (west side) of the proposed units matches the existing drainage pattern conveying flow from south to north. The owners of the . property to the north (Lots 10 and 11, Block 105 Harrison Addition) have written a letter accepting runoff from the site. Copies of the letters are attached in Appendix V. a. The proposed grading reduces the contribuitng area to Lot 11 from 0.41 acres prior to development to 0.32 acres after development. 7. The alley has a .minimum slope of 0.50% Concrete will be used in the alley and parking lot. The alley will act as a channel for the runoff from the site. a. The peak 100-year flow from the site and the portion of the alley that borders the site is 2.39 cfs. b. The capacity of the alley at the minimum slope is 2.83 cfs. c. Grading constraints do not allow an increase in the minimum slope of the alley without adversely affecting the adjoining properties. V. EROSION CONTROL: A. General Concept 1. Erosion control measures will be as identified on the Final Grading, Drainage and Erosion Control Plan. 2. An erosion control security deposit is required in accordance with City of Fort Collin policy (Chapter 7, Section C: SECURITY; page 7.23 of the City of Fort Collin Development Manual). In no instance shall the amount of the security be less than $1,000.00. 3. Refer to the Erosion Control Security Document located in Appendix H for the amount of the deposit. 4. Refer to the erosion control schedule on the Drainage and Erosion Control Plan for installation schedule of the erosion control measures. PAGE 6 Project No. 1536-08-97 Final Drainage and Erosion Control Report VI. VARIANCE REQUEST: A. Variance from City of Fort Collins Requirements 1. There will be no requests for any variances from the City of Fort Collins Storm Drainage Criteria for The Howes Street Hideaways. VII. CONCLUSIONS: A. Compliance with Standards 1. All drainage analysis has been performed according to the requirements of the City of Fort Collins Storm Drainage Criteria Manual, the City of Fort Collins policy, and the Old Town Master Drainage Basin Plan. 2. All Erosion Control design complies with the City of Fort Collins Erosion Control Reference Manual and generally accepted practices. B. Drainage Concept 1. The drainage design for The Howes Street Hideaways is in accordance with the City of Fort Collins requirements and the recommendations of the Master Drainage Basin Plan for Old Town Basin. 2. There will be no adverse downstream effects due to the development of the site. 1. Fort Collins Storm Drainage Criteria Manual 2. Urban Drainage and Flood Control District Drainage Criteria Manual 3. Fort Collins Storm Erosion Control Reference Manual 4. Old Town Master Drainage Basin Plan; Prepared by Resource Consultants & Engineers, Inc.; Dated January 7, 1993 5. Final Drainage and Erosion Control Report for Mulberry Green ; Prepared by Shear Engineering Corporation; Project No: 1151-24-95; Dated: June, 1996 I APPENDIX I Storm Drainage Calculations APPENDIX I Storm Drainage Calculations PLOW SUMMARY FOR HOWES STREET HIDEAWAY DESIGN CONTRIBUTING AREA C2 C10 C100 Tc Tc I2 I10 I100 Q2 Q10 Q100 PAGE POINT SUB 2,10 100 BASIN(S) ac. min. min iph iph iph cfs cfs cfs r rrrr+rrrrrrrrrrxrrrxrrrrrr+rr+rrxrxr+r+trrrtttr rtrttttrtrrr rrrrrr+r++♦+rrrrrrrrrrrr+rrrr+rrrrr rrrrr 1 Aw 0.32 0.43 0.43 0.54 11.00 11.00 2.46 4.31 6.92 0.34 0.59 1.20 5 2 Ae & ALLEY 0.39 0.72 0.72 0.90 11.50 11.50 2.42 4.24 6.82 0.68 1.19 2.39 6 3 ROW 0.17 0.77 0.77 0.97 7.50 7.50 2.92 5.05 8.22 0.38 0.66 1.36 0 C I SHEAR ENGINEERING CORPORATION PAGE 2 SUMMARY OF SUBBASIN BREAKDOWN PROJECT: HOWES STREET HIDEAWAYS DATE: 03/27/97 PROJ NO :1536-08-97 BY MEO FILE: HSHBASIN PLATTED AREA HOWES STREET HIDEAWAYS 0.63 ACRES ROW 0.17 ACRES ALLEY 0.07 ACRES TOTAL 0.87 ACRES DEVELOPED CONDITIONS IMPERVIOUS PERVIOUS , SUB- GRAVEL ASPHALT ROOF/ LAWN C2 C100 BASIN CONCRETE DRIVES Cfactor 0.50 0.95 0.95 0.20 % IMPERVIOUS 13.00% 100.00% 100.00% 0.00% ACRES ACRES ACRES ACRES ACRES trrrrrrr+rrrrrrrrrrrrrrrrrrrrrrrtr rtrrrrrrrrrrrrrrtrtrrr ttttrrt++rrr+rt+ SITE 0.63 0.00 0.08 0.22 0.33 0.56 0.70 1/2 ROW 0.17 0.00 0.13 0.00 0.64 0.77 0.97 ALLEY 0.07 0.00 0.07 0.00 0.00 0.95 1.00 TOTAL 0.87 0.00 0.28 0.22 0.37 0.63 0.79 Aw 0.32 0.00 0.01 0.09 0.22 0.43 0.54 Ae 0.32 0.00 0.07 0.13 0.12 0.67 0.84 Ae&ALLEY 0.39 0.00 0.14 0.13 0.12 0.72 0.90 % IMPERVIOUS = 57.47% - INCLUDES 1/2 ROW AND ALLEY AND DEVELOPED SITE % IMPERVIOUS = 47.62% - SITE ONLY- DEVELOPED CONDITIONS % IMPERVIOUS = 15.87% - SITE ONLY- EXISTING CONDITIONS SURFACE CHARACTERISTICS STREETS ASPHALT CONCRETE GRAVEL ROOFS LAWNS SANDY SOIL FLAT < 2% AVERAGE 2 - 7% STEEP > 7% LAWNS HEAVY SOIL SHEAR ENGINEERING CORPORATION SUB -BASIN BREAKDOWN FOR HOWES STREET HIDEAWAYS EXISTING CONDITIONS PROJECT :HOWES STREET HIDEAWAYS PROJ.NO. :1536-08-97 DATE: 03/27/97 LOCATION :OLD TOWN BY: MEO FILE :HSHBASIN NOTES :SITE ONLY RUNOFF COEF. AREA C C+A % (acres) IMPERVIOUS 0.000 0.950 0.000 100.00% 0.0000 0.010 0.950 0.010 100.00% 0.0100 0.000 0.500 0.000 50.00% 0.0000 0.090 0.950 0.086 100.001, 0.0900 0.000 0.100 0.000 0.00% 0.0000 0.000 0.150 0.000 0.00% 0.0000 0.000 0.200 0.000 0.00% 0.0000 FLAT < 21, 0.530 0.200 0.106 AVERAGE.2 - 7% 0.000 0.250 0.000 STEEP > 7% _ 0.000 0.350 0.000 TOTAL AREA 0.630 0.201 C2 C10 C100 COMPOSITE C VALUE 0.319 0.319 0.399 % IMPERVIOUS 15.87% SITE ONLY 0.00% 0.0000 0.00% 0.0000 0.00% 0.0000 0.1000 PAGE 3 SURFACE CHARACTERISTICS STREETS ASPHALT CONCRETE GRAVEL ROOFS LAWNS SANDY SOIL FLAT < 2% AVERAGE 2 - 7% STEEP > 7% LAWNS HEAVY SOIL SHEAR ENGINEERING CORPORATION SUB -BASIN BREAKDOWN FOR HOWES STREET HIDEAWAYS DEVELOPED CONDITIONS PROTECT :HOWES STREET HIDEAWAYS PROJ.NO. :1536-08-97 DATE: 03/27/97 LOCATION :OLD TOWN BY: HBO FILE :HSHBASIN NOTES :SITE ONLY RUNOFF COEF. AREA C C*A % (acres) IMPERVIOUS 0.060 0.950 0.057 100.00% 0.0600 0.020 0.950 0.019 100.00% 0.0200 0.000 0.500 0.000 50.00% 0.0000 0.220 0.950 0.209 100.00% 0.2200 0.000 0.100 0.000 0.00% 0.0000 0.000 0.150 0.000 0.00% 0.0000 0.000 0.200 0.000 0.00% 0.0000 FLAT < 21, 0.330 0.200 0.066 AVERAGE 2 - 7% 0.000 0.250 0.000 STEEP > 7% 0.000 0.350 0.000 TOTAL AREA 0.630 0.351 C2 C10 C100 COMPOSITE C VALUE 0.557 0.557 0.696 % IMPERVIOUS 47.62% SITE ONLY 0.00% 0.0000 0.00% 0.0000 0.00% 0.0000 0.3000 PAGE 4 SHEAR ENGINEERING CORPORATION FLOW TO CONCENTRATION POINT 1 FROM SUBBASIN Aw PROJECT: HOWES STREET HIDEAWAY: DATE 03/27/97 LOCATION:FORT COLLINS PROS. NO.1536-08-97 FILE: HSHRUN BY MEO NOTE: CP-1 IS NEAR THE CENTER OF THE SITE AT THE NORTH PROPERTY LINE AREA (A)= 0.320 ACRES RUNOFF CORF. (C) - 2 YEAR 10 YEAR 100 YEAR C = �0.43 0.43 0.54 SEE SPREAD SHEET ATTACHED ON PAGE 2 TIME OF CONCENTRATION (Tc) OVERLAND TRAVEL TIME (Ti) LENGTH = 85 FEET SLOPE = 0.70 t 2 YEAR 10 YEAR 100 YEAR C 0.20 0.20 0.25 Ti (min)= 17.45 17.45 16.48 TRAVEL TIME (Tt)=L/(60*V) FLOW TYPE L (ft) = 145 S (It) _ 0.5 GUTTER L (ft) _? S (}) _? ? L (ft) _? S (t) _? ? L (ft) _? S (4) _? ? L (ft) _? S (i) _? ? L (ft) _? S (i) =7 ? L (ft) _? S (6) _? ? NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2 TOTAL LENGTH = 230 L/180+10= 11.28 < Tc =Ti+TOTAL TRAVEL TIME 2 YEAR 10 YEAR 100 YEAR Tc.(min)= 11.28 11.28 11.28 USE Tc = 11 11 11 INTENSITY (I) (iph) 2 YEAR 10 YEAR 100 YEAR I = 2.46 4.31 6.92 NOTE: INTENSITIES TAKEN FROM FIGURE 3-1 RUNOFF (Q= CIA) (cf6) 2 YEAR 10 YEAR 100 YEAR Q = 0.34 0.59 1.20 PAGE 5 V (fps) = 1.5 Tt(min)= 1.61 IV (fps) _? Tt(min)= .0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 TOTAL TRAVEL TIME (min) = 1.61 19.07 =Ti+Tt CHOOSE LESSER CONCLUDE:PEAK FLOW FROM WESTERN PORTION OF SITE AFTER DEVELOPMENT TO LOT 11 a SHEAR ENGINEERING CORPORATION PAGE 6 FLOW TO CONCENTRATION POINT 2 FROM SUBBASIN As & ALLEY PROJECT: HOWES STREET HIDEAWAY DATE 03/27/97 LOCATION:FORT COLLINS PROJ. NO.1536-08-97 FILE: HSHRUN BY HBO NOTE: CP 2 IS W NE CORNER OF SITE IN ALLEY AREA (A)= 0.390 ACRES RUNOFF COBF. (C) 2 YEAR 10 YEAR 100 YEAR C = 0.72 0.72 0.90 SEE SPREAD SHEET ATTACHED ON PAGE 2 TIME OF CONCENTRATION (Tc) OVERLAND TRAVEL TIME (Ti) LENGTH = 100 FEET SLOPE = 0.50 lk 2 YEAR 10 YEAR 100 YEAR C = 0.20 0.20 0.25 Ti (min)= 21.16 21.16 19.98 TRAVEL TIME (Tt)=L/(60*V) FLOW TYPE L (ft) = 190 S (!) - 0.5 GUTTER L (ft) _? S M _? ? L (ft) _? S (%) _? ? L (ft) _? S _? ? L (ft) _? S _? ? L (ft) _? S _? ? L (ft) _? S (4) _? ? NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2 TOTAL LENGTH = 290 L/180+10= 11.61 < Tc =Ti+TOTAL TRAVEL TIME 2 YEAR .10 YEAR 100 YEAR Tc (min)= 11.61 11.61 11.61 USE Tc = 11.5 11.5 11.5 INTENSITY (I) (iph) 2 YEAR 10 YEAR 100 YEAR I = 2.42 4.24 6.82 NOTE: INTENSITIES TAKEN FROM FIGURE 3-1 RUNOFF (Q= CIA) (cfs) 2 YEAR 10 YEAR 100 YEAR Q = 0.68 1.19 2.39 CONCLUDE:PEAK FLOW FROM SITE TO ALLEY MINIMUM SLOPE OF ALLEY = 0.005 FT/FT CAPACITY OF ALLEY = 2.83 CPS SEE PAGE 8 V (fps) = 1.50 Tt(min)= V (fps) _? Tt(min)= V (fps) _? Tt(min)= V (fps) _? Tt(min)= V (fps) _? Tt(min)= V (fps) _? Tt(min)= V (fps) _? Tt(min)= TOTAL TRAVEL TIME (min) _ 22.09 =Ti+Tt 2.11 0.00 0.00 0.00 0.00 0.00 0.00 2.11 SHEAR ENGINEERING .CORPORATION PAGE 7 FLOW TO CONCENTRATION POINT 3 FROM SUBBASIN ROW PROJECT: HOWES STREET HIDEAWAY DATE 03/27/97 LOCATION:FORT COLLINS PROD. NO.1536-08-97 FILE: HSHRUN BY MHO NOTE: CP 1 IS NEAR THE CENTER OF THE SITE AT THE NORTH PROPERTY LINE AREA (A)= 0.170 ACRES RUNOFF COEF. (C) 2 YEAR 10 YEAR 100 YEAR C = 0.77 0.77 0.97 SEE SPREAD SHEET ATTACHED ON PAGE 2 TIME OF CONCENTRATION (TO OVERLAND TRAVEL TIME (Ti) LENGTH = 20 FEET SLOPE = 2.00 } 2 YEAR 10 YEAR 100 YEAR C = 0.20 0.20 0.25 Ti (min)= 5.99 5.99 5.66 TRAVEL TIME (Tt)-L/(60*V) FLOW TYPE L (ft) = 145 S (}) = 0.5 GUTTER L (ft) _? S (}) _? ? L (ft) =7 S (}) _? ? L (ft) _? S (}) _? ? L (ft) _? S (}) _? ? L (ft) _? S (}) _? ? L (ft) _? S (}) _? ? NOTE: ALL VELOCITIES TAKEN FROM FIGURE 3-2 TOTAL LENGTH = 165 L/100+10= 10.92 > Tc =Ti+TOTAL TRAVEL TIME 2 YEAR 10 YEAR 100 YEAR Tc (min)= 7.60 7.60 7.60 USE Tc = 7.5 7.5 7.5 INTENSITY (I) (iph) 2 YEAR 10 YEAR 100 YEAR I = 2.92 5.05 8.22 NOTE: INTENSITIES TAKEN FROM FIGURE 3-1 RUNOFF (Q= CIA) (cfs) 2 YEAR 10 YEAR 100 YEAR Q = 0.38 0.66 1.36 V (fps) = 1.5 Tt(min)= 1.61 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 V (fps) _? Tt(min)= 0.00 TOTAL TRAVEL TIME (min) = 1.61 7.60 =Ti+Tt CHOOSE LESSER CONCLUDE:PEAK FLOW TO NORTWEST CORNER OF PROPERTY IN STREET FROM 1/2 ROW SHEAR ENGINEERING CORPORATION PAGE e CHANNEL CAPACITY PROJECT NAME: HOWES STREET HIDEAWAYS DATE: 03/27/97 PROJECT NO. 1536-08-97 BY : MEO SWALE DESCRIPTION:PAVED ALLEY WITH INVERTED CROWN PILE: HSHCHAN CAPACITY OF TRIANGULAR OR TRAPEZOIDAL CHANNEL CHANNEL CONFIGURATION: TRIANGULAR Q100 (cfa) = 2.74 CHANNEL LINING: CONCRETE REFER TO PAGE 6 Da Db Dc Sc n W I (ft) (ft) (ft) (M) (ft) (ft) ---- ---- ---- ---- ----- ---- ---- 10.00 10.00 0.20 0.500 0.016 0.00 0.05 - 0.02 = LEFT BANK SLOPE 0.02 = RIGHT BANK SLOPE DEPTH WIDTH AREA PERIM R 2/3 Sc 1/2 Q V (ft) (ft) (s.f.) (ft) (A/P) (cfe) (ft/aec) -------------------------------------------------------- 0.20 20.00 2.00 20.00 0.22 0.07 2.83 1.41 0.15 15.00 1.13 15.00 0.18 0.07 1.31 1.17 0.10 10.00 0.50 10.00 0.14 0.07 0.45 0.89 0.05 5.00 0.13 5.00 0.09 0.07 0.07 0.56 0.00 0.00 0.00 0.00 0.00 0.07 0.00 0.00 r rrrrrr+xx++t+++r+x+r+rrrr++rrrrrrrrrrrrrrrrrrrrrrrrrrrrrxxrxr+xrr•rrrr• DEPTH WIDTH AREA PERIM R 2/3 Sc 1/2 Q V (ft) (ft) (s.f.) (ft) (A/P) (cfs) (ft/sec) CONCLUDE:ALLEY CAPACITY IS ADEQUATE SLOPE OF ALLEY INCREASES TO NORTH APPENDIX II Erosion Control Calculations Erosion Control Sequencing schedule Erosion Control security deposit estimate RAINFALL PERFORMANCE STANDARD EVALUATION PROJECT: HOWES STREET HIDEAWAYS STANDARD FORM A COMPLETED BY: MARK OBERSCHMIDT DATE: 03/27/97 r rrrrrr r.r:xxtttxxrttrtrrrrrrrrrrrrrrrrrrrrrtrretrrr xrrrrrrrrrrrttrttxttrttrtrtxrxtxtrrrxrt DEVELOPED BRODIBILITY Asb Lsb Ssb Lb Sb PS SUBBASIN t♦rrrrrrrr rrrrrrrrrrrrr»rrrrrrrrrrt+rt•rrrrrrrrrrr ZONE (ac) (ft) M rrrrr+trttrrrerrrrrrrrrr (feet) (t) M rrrrr»rrrrrrrr IA MODERATE 0.47 100.00 1.00 47 0.47 1B MODERATE 0.40 90.00 1.00 36 0.40 rr trrrtrxrrtrrtrx+rrtttxtrxttt+ttttrtxtxtxxtrtrtr+rrrr rrrtttr tt xxrrtrrtt 0.87 95.40 1.00 LINEAR INTERPOLATION NOT REQUIRED USE L = 100 AND S = 1.00 THEREFORE THE PERFORMANCE STANDARD = 74.6 PERCENT CONCLUDE:PERFORMANCE STANDARD = 0.00% EROSION CONTROL PLAN OVERALL EFFECTIVENESS MUST EXCEED THIS EFFECTIVENESS CALCULATIONS STANDARD FORM B PROTECT: HOWES STREET HIDEAWAY PROJ. NO.1536-08-97 BY: MARK OBERSCHMIDT DATE 03/27/97 ------------------------------------------------------------------------------------------ EROSION CONTROL C-FACTOR P-FACTOR COMMENT METHOD VALUE VALUE ------------------------------------------------------------------------------------------ ROUGHBNED GROUND 1.00 0.9 ROOF AREAS SUBBASIN Al ONLY SILT PENCE 1.00 0.5 SUB -BASINS Al ONLY ASPHALT 0.01 1.0 SUB -BASINS Al ONLY SOD 0.01. 1.0 SUB -BASINS Al ONLY ESTABLISHED VEGETATION 0.02 1.0 SUBBASIN A2 ONLY ------------------------------------------------------------------------------------------ MAJOR PS SUB AREA CALCULATIONS BASIN t BASIN acre AREA C. P ------------------------------------------------------------------------------------------ ALL 74.60% Al 0.47 ROOF 0.09 ACRES 1.00 0.90 SOD 0.24 ACRES 0.01 1.00 EQUATIONS ASPHALT 0.14 ACRES 0.01 1.00 C = WEIGHTED AVG OF C X AREA P = (WEIGHTED AVG OF P X AREA) X P. C - 0.1996 EFF = (1 - P X C) X 100 P = 0.4904 EFF 90.21% ------------------------------------------------------------------------------------------ NO WORK DONE IN SUBBASIN A2 0.40 ACRES THEREFORE EFF = 100.00% ++r++rrx+x•x•x•xx+xx+xx+♦r+r+rrr+rxr+x+xxxx+xxx++r+xr+r++rx+++rexxxx xxxx+rx+r+r++rxxxrxxx• TOTAL AREA = 0.87 ACRES OVERALL EFFECTIVENESS = 94.71$ > 74.60$ CONCLUDH:HROSION CONTROL PLAN IS EFFECTIVE Howes Street Hideaways Const Seq R-Client / Rayline/ Harrisons / Erosion / Const Seq. 1536-08-97 Date: 02/28/97 Revised: 02/28/97 CONSTRUCTION SEQUENCE PROTECT: Howes Street Hideaways STANDARD FORM C SEQUENCE FOR 1997-1998 ONLY COMPLETED BY: MEO / Shear Engineering Corp. Indicate by use of a bar line or symbols when erosion control measures will be installed. Major modifications to an approved schedule may require submitting a new schedule for approval by the City Engineer. Year 197 98 Month J J A S O N D J F M A M J OVERLOT GRADING WIND EROSION CONTROL * Soil Roughening Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant Other RAINFALL EROSION CONTROL STRUCTURAL: Sediment Trap/Basin Inlet Filters Straw Barriers Silt Fence Barriers Sand Bags Bare Soil Preparation Contour Furrows Terracing Asphalt/Concrete Paving Other VEGETATIVE: Permanent Seed Planting Mulching/Sealant Temporary Seed Planting Sod Installation Nettings/Mats/Blankets Other *** *** *** *** *** *** STRUCTURES: INSTALLED BY: OWNER MAINTAINED BY: OWNER VEGETATION/MULCHING CONTRACTOR: OWNER DATE PREPARED: 0212E 97 DATE SUBMITTED: 03/25/98 APPROVED BY THE CITY OF FORT COLLINS ON: April 4, 1997 Project No: 1536-08-97 Basil Hamdan City of Fort Collins Stormwater Utility P.O. Box 580 Ft. Collins, Colorado 80522 Re: Erosion Control Cost Estimate Howes Street Hideway Lots 12-14, Block 105, Harrison's Addition; Fort Collins, Colorado Dear Basil, Attached is the erosion control security deposit estimate for Howes Street Hideaway ESTIMATE 1: 145 LF of Silt Fence ® $ 3.00 per LF TOTAL ESTIMATED COST: ESTIMATE 2: re -vegetate the disturbed area of 0.32 acres at $636.00 per acre TOTAL ESTIMATED COST: $ 435.00 $ 435.00 x 1.50 S 652.50 203.52 $ 203.52 x 1.50 $ 305.28 In no instance shall the amount of the security be less than $1,000.00. Therefore, the total required erosion control security deposit for Lots 12-14, Block 5, Harrison's Addition will be $ 1,000.00. If you have any questions, please call at 226-5334. Sincerely, VF� Mark Oberschmidt Shear Engineering Corporation MEO/ meo cc: Rayline Development Corporation Dave Stringer, City of Fort Collins 4836 S. College, Suite 12 Ft. Collins, CO 86525 (970) 226.5334 FAX (970) 282-0311 SHEAR' ENGINEERING CGRPGRATIGN April 4, 1997 Project No: 1536-08-97 Re: EROSION CONTROL SECURITY DEPOSIT REQUIREMENTS: Lots 12-14, Block 105, Harrison's Addition; Fort Collins, Colorado A. An erosion control security deposit is required in accordance with City of Fort Collins policy (Chapter 7, Section C: SECURITY; page 7.23 of the City of Fort Collins Development Manual). In no instance shall the amount of the security be less than $ 1000.00. a. The cost to install the proposed erosion control measures is approximately $ 435.00 Refer to the cost estimate attached in Appendix I. 1.5 times the cost to install the erosion control measures is $ 652.50 b. Based on current data provided by the City of Fort Collins Stormwater Utility, and based on an actual anticipated net affected area which will be disturbed by construction activity (approximately 0.32 acres), we estimate that the cost to re - vegetate the disturbed area will be $ 203.52 ($ 636.00 per acre x 0.32 acres). 1.5 times the cost to re -vegetate the disturbed area is $ 305.28 The $ 636.00 per acre for re -seeding sites of less than 5 acres was quoted to us by the City of Fort Collins Stormwater Utility personnel. CONCLUSION: The erosion control security deposit amount required for Lots 12-14, Block 5, Harrison's Addition will be $ 1,000.00. 4836 S. College, Suite 12 Ft. Collins, CO 80525 (970) 226-5334 FAX (970) 282-031 1 APPENDIX III Backup Diagrams and Exhibits Table 3-3; Rational Method Runoff Coefficients for Composite Analysis Table 3-4; Rational Method Frequency Adjustment Factors Figure 3-2; Estimate of Average Flow Velocity for Use with the Rational Formula Figure 3-1; City of Ft. Collins Rainfall Intensity Duration Curve R-M-P Medium Density Planned Residential District — designation for medium density areas planned as a unit (PUD) to provide a variation in use and building placements with a minimum lot area of 6,000 square feet. R-L-M Low Density Multiple Family District — areas containing low density multiple family units or any other use in the R-L District with a minimum lot area of 6,000 square feet for one -family or two-family dwellings and•9,000 square feet for multiple -family dwellings. M-L Low Density Mobile Home District — designation for areas for mobile home parks containing independent mobile homes not exceeding 6 units per acre. M-M Medium Density Mobile Home District — designation for areas of mobile home parks containing independent mobile homes not exceeding 12 units per acre. B-G General Business District — district designation for downtown business areas, including a variety of permitted uses, with minimum lot areas equal to 1/2 of the total floor area of the building. B-P Planned Business District — designates areas planned as unitdevelopments to provide business services while protecting the surrounding residential areas with minumum lot areas the same as R-M. H-B Highway Business District — designates an area of automobile -orientated busi- nesses with a minimum lot area equal to 1/2 of the total floor area of the building. B-L Limited. Business District — designates areas for neighborhood convenience centers, including a variety of community uses with minimum lot areas equal to two times the total floor area of the building. C Commercial District —designates areas of commercial, service and storage areas. I-L Limited Industrial District — designates areas of light industrial uses with a minimum area of lot equal to two times the total floor area of the building not to be less than 20.000 square feet. I-P Industrial Park District —designates light industrial park areas containing controlled industrial uses with minimum lot areas equal to two times the total floor area of the building not to be less than 20,000 square feet. I-G General Industrial District — designates areas of major industrial development. T Transition District — designates areas which are in a transitional stage with regard to ultimate development. For current and more explicit definitions of land uses and zoning classifications, refer to the Code of the City of Fort Collins, Chapters 99 and 118. Table 3-3 RATIONAL METHOD RUNOFF COEFFICIENTS FOR COMPOSITE ANALYSIS Character of Surface Runoff Coefficient Streets, Parking Lots, Drives: Asphalt................................................................................................ 0.95 95 Concrete............................................................................................. 0. Gravel................................................................................................. 0.50 Roofs.......................................................................................................... 0.95 Lawns, Sandy Soil: 0.1 Flat<2%............................................................................................. 0.5 Average2 to 7%.................................................................................. 0.20 Steep>7%.......................................................................................... Lawns, Heavy Soil: Flat<2%............................................................................................. 0.20 Average2 to 7%.................................................................................. 0.25 Steep>7%......... :................................................................................ 0.35 MAY 1984 3-4 DESIGN CRITERIA 3.1.7 Time of Concentration In order to use the Rainfall Intensity Duration Curve, the time of concentration must be known. This can be determined either by the following equation or the "Overland Time of Flow Curves" from the Urban Storm Drainage Criteria Manual, included in this report (See Figure 3-2). Tc= 1.87 (1.1 -CC,) D"Z S t� Where Tc = Time of Concentration, minutes S = Slope of Basin, % C = Rational Method Runoff Coefficient D = Length of Basin, feet C, = Frequency Adjustment Factor Time of concentration calculations should reflect channel and storm sewer velocities as well as overland flow times. 3.1.8 Adjustment for Infrequent Storms The preceding variables are based on the initial storm, that is, the two to ten year storms. For storms with higher intensities an adjustment of the runoff coefficient is required because of the lessening amount of infiltration, depression retention, and other losses that have a proportionally smaller effect on storm runoff. These frequency adjustment factors are found in Table 3-4. Table 3-4 RATIONAL METHOD FREQUENCY ADJUSTMENT FACTORS Storm Return Period (years) 2to10 11 to 25 26 to 50 51 to 100 3.2 Analysis Methodology Frequency Factor C, 1.00 1.10 1.20 1.25 Note: The product of C times C, shall not exceed 1.00 The methods presented in this section will be instituted for use in the determination and/or verification of runoff at specific design points in the drainage system. These methods are (1), the Rational Method and (2) the Colorado Urban Hydrograph Procedure (CUHP). Other computer methods, such as SWMM, STORM, and HEC-1 are allowable if results are not radically different than these two. Where applicable, drainage systems proposed for construction should provide the minimum protection as determined by the methodology so mentioned above. 3.2.1 Rational Method For drainage basins of 200 acres or less, the runoff may be calculated by the Rational Method, which is essentially the following equation: Q = C,CIA Where Q = Flow Quantity, cfs A =Total Area of Basin, acres C, = Storm Frequency Adjustment Factor (See Section 3.1.8) C = Runoff Coefficient (See Section 3.1.6) 1 = Rainfall Intensity, inches per hour (See Section 3.1.4) 3.2.2 Colorado Urban Hydrograph Procedure For basins larger than 200 acres, the design storm runoff should be analyzed by deriving synthetic unit hydrographs. It is recommended that the Colorado Urban Hydrograph Procedure be used for such analysis. This procedure is detailed in the Urban Storm Drainage Criteria Manual, Volume 1, Section 4. MAY 1984 3-5 DESIGN CRITERIA No Text DRAINAGE CRITERIA MANUAL RUNOFF 5C 30 F 20 z cc U w 10 z w IL b O 5 Cn w cc 3 O cU 2 cc w F 3 1 �//1111I� ■■ r�■■ � � I • Ii�llll� / S�®� ,■■■■MEN ���� �■ON�I■ ■■���r�■■■���■ ,■■rim � ■■ ■■■■�� ....... ►..�■ :... . .■..C■■■■.�■ .■�►...D..-.■►AR ���.■■....�. 011 MEN ON 5� 4 .0 •3 1 2 3 5 10 20 VELOCITY AN FEET PER SECOND FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR USE WITH THE RATIONAL FORMULA. *MOST FREQUENTLY OCCURRING "UNDEVELOPED" LAND SURFACES IN THE DENVER REGION. REFERENCE: "Urban Hydrology For Small Watersheds" Technical Release No. 55, USDA, SCS Jan. 1975. 5 =1-84 URBAN DRAINAGE & FLOOD CONTROL DISTRICT r— DRAINAGE CRITERIA MANUAL 50 30 F- 20 z w U "W 10 z w O 5 w cc 3 O' U 2 W H 3 1 5 .1 RUNOFF I Iri■i �� ���� M moll �IAM ►I /I■ I ��C■■��� ...►.ID.FA ...I�� ►�. C �.��.....� MEN s 5 1 2 3 5 10 20 VELOCITY IN FEET PER SECOND FIGURE 3-2. ESTIMATE OF AVERAGE FLOW VELOCITY FOR USE WITH THE RATIONAL FORMULA. *MOST FREQUENTLY OCCURRING"UNDEVELOPED" LAND SURFACES IN THE DENVER REGION. REFERENCE: "Urban Hydrology For Small Watersheds" Technical Release No. 55, USDA, SCS Jan. 1975. 5 =1-84 URBAN DRAINAGE & FLOOD CONTROL DISTRICT APPENDIX IV Portions of the Old Town Master Drainage Basin Plan —f\ rnln W.V 7cz-7 r :R Pros ect Rd. Rect Rd. Williams ra e Rd.1 Figure 1.1: GENERAL. LOCATION MAP z MASTER DRAINAGE TOLD TOWN Scale: BASIN PLAN for the CITY of FORT COLLINS 1.2 LLJ N ua» r: LU = d o r \ I I•Y I. I .. j w Z zo 00 IL� - ':� L:1 co ' 'JI �( I 1 r l t r r1i' IiiN _ • : -11 �� n H-.1/L a:: I__.._I l ..___.Y I f7 I •I - - U)`— r --:.-• mac. > -- I--. I` i c a� . II I ' ••� rJvv ---_— , 1 c� I ; Table 4.1. Design Storms for Old Town Basin. Rainfall 1'nt s: Ending in 2 Year X V 5 Year 10 Year 25 Year 100=Year 5 0.12 0.36 0.48 0.48 0.60 10 0.36 0.60 0.60 0.72 0.96 15 0.48 1 0.60 0.72 0.96 1.44 20 0.60 0.84 0.96 1.32 1.68 25 0.84 1.56 2.16 2.28 3.00 30 1.80 2.52 3.12 3.72 5.04 35 = 3.24 4.68 5.64 6.84 9.00 40 1.08 2.04 2.28 2.88 3.72 45 0.84 1.08 1.12 1.56 2.16 50 0.48 0.72 0.84 1.08 1.56 55 0.36 0.48 0.72 0.84 1.20 60 0.36 0.48 0.60 0.72 0.84 65 0.36 0.48 0.60 0.72- 0.60 70 0.24 0.36 0.48 0.48 0.48 75 0.24 0.36 0.36 0.36 0.36 80 0.24 0.24 0.24 0.36 0.36 85 0.24 0.24 0.24 0.36 0.24 90 0.12 0.24 0.12 0.36 0.24 95 0.12 0.12 0.12 0.24 0.24 100 0.12 0.12 0.12 0.12 0.24 105 0.12 0.12 0.12 0.12 0.24 110 0.12 0.12 0.12 0.12 0.24 115 0.12 0.12 0.12 0.12 0.12 120 0.12 0.12 0.12 0.12 0.12 at hand, recognizing that it is always possible to make additional refinements or revisions to any model. 4.1.2 Basin Subdivision As can be seen from Figure 4.1, the Old Town Basin below Larimer County Canal No. 2 was subdivided into three smaller subbasins numbered 1, 2, and 3. Subbasin 1 encompassed the area in the northern part of the drainage; Subbasin 2 encompassed the central part, including the downtown area; and Subbasin 3 covered the southern part. Each of the subbasins was drained by a major storm sewer. 4.3 Table 4.3. Differences in Impervious Area Percentages for Existing and Future Conditions. Subcatchment... Percent Impervious Number Existm g Future 6 40 70 102 50 70 108 40 60 109 40 60 201. 40 60 203 50 70 204 60 70 205 50 70 206 40 60 211 40 60 304 40 60 305 40 60 312 40 50 360 20 40 361 60 100 4.9 No Text No Text Storage functions were used at elements 203, 204, 205, and 206 in Subbasin 2 to simulate the ponding of floodwaters behind the various north -south streets with high crowns. During the 100-year flood, these ponds filled before the peak runoff. Once filled, the ponds did little to attenuate flood peaks; the inflow rate essentially equaled the outflow rate. However, this was not the case with the less severe storms. .Snlitter_functions were used at elements.227 228 2�9 4 F 99r� distribute spillsAam the aondina areas behind College and Mason to either the downtown area or eet. Splitter functions were used at elements 215-216-217 and 218- ;> 219-220 to direct a portion of the runoff near the intersection of Myrtle and Peterson Streets into Subbasin 3.• Splitter functions were also used at elements 324-325-326 and 327-328-329to determine the amount of water that would be carried under Riverside through the storm drains and the amount that would be left flowing down Riverside parallel to the railroad tracts. A splitter function was used at elements 357-358-359to account for surface returns back to Mulberry along Smith Street..., Runoff in Upper Part of Subbasin 3. In the upper partof Subbasin 3, most of the . flood runoff, which included spills from the Larimer County.Canal No. 2, collected along Elizabeth Street. The runoff moved across Shields and onto CSU property. Storm drains diverted some of the runoff to the south and into the Spring Creek drainage, although most of the runoff flowed across CSU through the intramural field and eventually discharged into an open reach of the Arthur Ditch. The Arthur Ditch diverted much of the intercepted.. flood runoff into a box culvert that extended under the CSU campus. The culvert, in turn, carried water out of the Old Town drainage and into the Spring Creek drainage.' The capacity of the open reach of the ditch was exceeded during the course of the 100-year flood, resulting in excess waters spilling into the CSU lagoon located immediately. .downstream of the ditch near the CSU Student Center: 77. Routing and storage of floodwaters in the Arthur Ditch and CSU lagoon were simulated through the use of splitter functions at elements 353-354-355 and 336-337-338 and through the use of the storage*function.for element 315., It was assumed that the Arthur Ditch was carrying 60 cfs of irrigation water for the duration of the flood. It was estimated that the ditch could carry an additional 35 cfs before water, would overtop the.: ditch banks and spill into the CSU lagoon. - Inflows exceeding 35 cfs were routed into the lagoon using the splitter function for elements 353-354-355. It was further estimated that releases through the Arthur Ditch box culvert under the CSU campus would increase once . the water elevation in the lagoon reached the top of the open ditch. The dam creating the CSU lagoon is higher in elevation than the Arthur Ditch.: Estimates for the additional . surcharged capacity of the box culvert were incorporated into the release rates for the storage pond function at element 315. Surface spills, which would result from a complete filling of the lagoon; were simulated to occur first at the low spot near the intersection of Pitkin and Center Streets and then over the top of the dam itself near the Student Center. The splitter function for elements 336-337-338 was used to distribute any surface spills. Surface spillage did not occur from the lagoon for the future condition runs. The. regional detention pond near Skyline and Elizabeth Streets coupled with improvements to the Larimer #2 Canal, reduces the current spilling into the Old Town Basin. The future condition runs assumed those proposed improvements. The simulated spillage from the lagoon for existing: conditions was all to the south, near the intersection of Pitkin and Center; no spillage occurred over the top of the dam into the lower part of Subbasin 3. 4.18 v a� 7 c ,r c O U N DI `m s U m c O �r M d LL T U c a) LT a� LL. 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U) o M m a m m a m a M m m m a m )ri m m a M m °� v M ai 'a a O7 m a m a m m O1 m °) so m m a �i m m M m o M m n m m c c .V. r o 0 0 o 0 n - 0 rn M m 0 m m m no n m 0 O n v o W n O m o a mM 0000 O n m n m m CO I m M a m U .0 Ip _ a N a M a a a a a a U v cc a vpi m N m M a m 5.17 ' m m a 0 10 0 0 0 Nco cN�1 M M M a m 0) O N O m N N M n Ol y o CD to m m n N m m 0 p m. Of Gn y0 a)y m n . } .. .:...... ,. a N {r a a a m a m m m m a a a a a m C. �' > :.� N N N N tlol b m M N m N N O O N M N N N N Cl)w, c O U W N M n M m ^ m 01 O tLl n m N ^ M N ^ m C pj N m m O O a m a n °' n °f m m m v a m m U y m LL } N b O O O O O a �. >.. u: m cV m m N N O O O W O a Oa O .. .. .. N N N N m aOD V N c") WN - �- .-- y _ to ^ m 0 O m N n M o N O m Qi m D) O1 OI O t0 f^O fN0 t0 N m cd p C m to m O m m n ^ n m n n m a, a a ma) Cl m m w a a a a a 0 cr o LL o o m 0 0 m m 0 0 m m 0 n m o 0 0 'o > V O O N LL w m N a O ai O cp m .. 3 m m m m o �: m m to n n ^ n of 0 ui a a a a m m m m n n co m .n m N b o 0 0 0 O O o o 0 0 > LL m m 0 a a m 0 0 m 0 o....:. N N f� co 00 of m m m o .- O r� a) mm���MWN�o a v v v O1 o m m m c c o c o 0 o O 0 "0 u m ^ M co O O O O O O O O 0 m O M m y m m Om N N .., .. L O L to co O cr) m Z �CO¢'. 1n N c00 cc m fND cM0 caD cND cy0 c^D lm0 cNp 5.18 j! t Figure 5.14: PROFILE of REACH 3 OLD TOWN MASTER ....... U, Q9 I I as DRAINAGE BASIN PLAN CITY of FORT COLLINS I Legend: —000 Z Z I= V.. 1bad RCE Til- - E- 6 Figure 5.15: PROFILE of REACH 4 OLD TOWN MASTER DRAINAGE BASIN PLAN CITY of FORT COLLINS Legend: 100 V.. F. RCE PONDING EXHIBIT NTS T 71 W + 7*—\y.. �.LLJ • , �ti�+ • �'� Gar, }� F ' MULBERRY STREET a( ` y fo 1' av- d e lf+.`rII'a.L A OXa. LI T�,` �O �I�G :fir. Ali X4982.8 Ilk J9 _ I \'• .rAji III ,,,+,`S -.. � "at"�?t�•ry a' ")tl ay � .>y�.' i � y -5„r � ,, _a* y �. .,e, X., \�!.'!.. _ - ) S y..`t" �, x..• 1. ` „! I• (�' r•r ��I n- LO ''.7Krr `LL X49 5'0 MYRTLE STRET`X4994,9 Vt X4993 4 �slb X4993.4:. Appendix V Correspondence A' -14-97 MON 09:48 CZE)TWE 9 FAX NO. 303 4! 2 . �_G0 . - G i; � ; April 10, 1997 Basil l tamddn City of Ft. Collins Storrnwater Utility P.O. Box 580 Ft Collins, CO 80524 RE' Howes Street Hideaways Previously, Lots 12-14, Block 105 Harrison's Addition Dear Basil. This letter i$ provided as statement of my OPProval and acceptance of storm flows from the neighboring property due to the improvements proposed by Rayline DeVelopment-Corp., with the project referred to as "Howes Stroot Hideaways". I understand that storm drainage patterns my be slightly adjusted from historic drainage. patterns which may have existed prior to completion of the proposed improvements, Please provide plan approval for "Howes Street Hideaways" Utilizing this letter as my approval and acceptance of drainage Patterns which my be slightly modified by the project. If you have questions concerning this statenlent, please do not hesitato to call at 6-74067. OW is7 Sincerely, W,�. Darrel Hardy Owner of Lot lo, Block 105 Harrivon's Addition 1536-08-97 APR-01-97 11:IF. AM RAYLINE. 970 223 06E:O P.01 April 1, 1997 Basil Hamdan City of Ft. Collins Stormwater Utility P.O. Box 580 Ft. Collins, CO 80524 RE: The Howes Street Hideaways Previously, Lots 12-14, Block 105 Harrison's Addition; Ft. Collins, Colorado Dear Basil, This letter is provided as statement of my approval of grading on my property and acceptance of storm flows from the neighboring property due to the improvements proposed by Rayline Development Corporation with the project referred to as Howes Street Hideaways". 1 understand that storm drainage patters my be slightly adjusted from historic drainage patters which my have existed prior to completion of the proposed improvements. Please provide plan approval for "Howes Street Hideaways" utilizing this letter as my approval and acceptance of drainage patters which my be slightly modified by the project. If you have questions concerning this statement, please do not hesitate to call at 970-927-4887. Sincere , Doug Owner of Lot 11, Block 105, Harrison's Addition Stuffer Enveloue Drainage and Erosion Control Plan • I I _ NOTE: MINIMUM ALLO\VAIILL MIS11ED FLOOR k( } -----. ^ �I I - ELEVA'l10\ Ib 95.0 FEEL' LV UROLIt to PROVIDE L ` _6_e -- ' ---- YEAR REQUIRED 1 SEPARATION DRIN'THTHE OLD 00. H----- �yTr•h--- ( VEER FLOOD ELEVATION NOTED W '1'RL OLD -� (_ 'MOWN MASTER DRAINAGE BASIN PLAN. THE 1W- _ - YEAR FLOOD ELEVATION LY 93.5 ACCORDINC TO THE OLDTOWN HARDER DRAINAGE BASIN PLAN. k Sli few y It I -I ---}- B I STANDARD EROSION CON FROL CONSTRUCTION PLAN NOILS I 1 I R yI I Ir IWO �I 'nlo cn wrwac m -5f u r L 1 1 j IuwR grorw :Y � Ile I 14. ixl I ; I Y Y 11 Rclorlwu bo d[ I I :tl I j C'-' -..I II __ _- -_ -- - -- IreRuld µdapta aIflaw I EACH be aella Priar to arty,landJ Ig '. i1 f I �I I Y j 1. i (sink Wb pp data 1 All all u 1 r lCA b° fl J lt. 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I. - -. bi Al n--- — — - ---'- , r — -- --- --' — -- - — - ---- - - - v -- - - -- - - ---PA w SOU H HOWES STREET 100- RICNT-Of-WAY 1 , I - - - - - - - - - - - - - - - - - - - - - City of Fort Collins, Colorado UTMR PLAN APPROVAL APPROVED' •. ' ,wx,a wrt CHECKED AT ..�..�..... c3 __ _ _ __4 CHECKED art . - . .: CHECKED BY _ A. snm nrmurcx v < _ _ _ _ _ _ _ _ _ _ _ ,.. CHECKED By.M . 'C: - CHECKED 9 :. +, ; 9[Y15wX5 OIA PRIL 1997 NM CADIraK _ aul - nr[[ MA"TEfl GHADINO ELAN PROJECT 00. Site— m o`"'9o-" B.ws: RATLINE DEVELDPMENT CORPORATION �I SHEAR ENGINEERING CORPORATION 'pppjSHEETHiETS Car—w— Mral, FeD LbN. CM.kN L836 50, COLLEGE AVE. SUITE 12, PoBT COLLINS, COLOPADO 80525 LOTS 1%.-14-6LGOaK .1D5I HARRISON'S ADDITION 1536-08 97 _ Rm, 4 B,.�s. Smk '^ 1 = 20' APpraeE B.W.S. PHONE: (920) 226-5334 (970) 226-4451 PAX: (970) 282-0311 FORT COLWNS. COLORADO RATSrt .