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HomeMy WebLinkAboutDrainage Reports - 07/27/1995I 0 EROSION CONTROL REPORT FOR COUNTRY CLUB CORNER, A PLANNED UNIT DEVELOPMENT Lnndmnirh EROSION CONTROL REPORT FOR COUNTRY CLUB CORNER, A PLANNED UNIT DEVELOPMENT Prepared For.• Denver Holdings, Inc. 10065 E. Harvard Avenue, Suite 803 Denver, CO 80231 June 2, 1995 Project No. DENHO-94099C-04-110-AD CONSULTING ENGINEER Landmark Engineering Ltd. 3521 W. Eisenhower Boulevard Loveland, Colorado 80537 CERT►F►CA710N 1 hereby certify that this Erosion Control Report for Country Club Comer, A Planned Unit Development was prepared by me or under my direct supervision in accordance with the provisions of the City of Fort Collins Storm Drainage Design Criteria and Construction Standards for the Owners thereof. Patrick M. Mestos Colo. P.E. 13886 o \�\ CO�p`\``p [1 EROSION AND SEDIMENT CONTROL This report describes methods which are recommended to control wind erosion, water erosion and sediment during and after the construction of drainage structures and site grading. Discussion The clearing and stripping of land for site grading, overlot grading, or for the construction of drainage structures, and swales, may cause high localized erosion rates with subsequent deposition and damage to offsite properties. Uncontrolled, such erosion could destroy the aesthetic and practical values of individual sites, and cause damage to downstream property. In general, erosion and sediment control measures may consist of minimizing soil exposure, controlled runoff across exposed areas, and sediment control at drainage structures. Each of these measures is described below and should be utilized by the developer and/or the contractor during any construction activity which occurs at this site. General Erosion and Sediment Control Measures Minimizing Soil Exposure: Where practical, the construction area and duration of soil exposure should be kept to a minimum. All other areas should have a good cover of vegetation or mulch. Grading should be completed as soon as possible after commencement. A temporary cover crop, a permanent vegetative cover crop, or other landscaping should be established in the disturbed areas. Revegetation may consist of native grasses, lawn grasses, or various winter wheat. Decorative rock, flower gardens, or shrubs may also be utilized in the final landscaping to cover the soil. Reseeded areas should be mulched with straw or hay to protect exposed soil until vegetation is established. ' Controlled Runoff Across Exposed Areas: Where practical, construction may include constructing temporary swoles to intercept and direct storm water around ' exposed areas. Swales can be constructed to control surface water which collects on exposed areas and prevent gross erosion in the form of gullies. Riprap, ' or other temporary erosion control devices may be installed to control. storm water velocities across exposed areas. Sediment Control: Temporary and/or permanent sediment control devices may be installed at the major drainage structures and flow concentration points. Such structures can be used to intercept and trap sediment once produced and prevented from migrating offsite onto downstream property. Erosion Control Plan The proposed erosion control measures are presented on the Erosion Control Plan ' of the Utility Drawings for this project. The evaluation of the Performance Standard and Net Effectiveness are presented in the Appendix. In summary, the erosion control measures consist of: 1. Utilization of the interim detention pond for a sedimentation basin trap until ' construction is complete and the site is landscaped. The interim detention pond has sufficient volume so that additional volume for sedimentation is ' not required. The Contractor will be required to control the grading so that runoff is directed to the sediment pond during construction. ' 2. Installation of gravel filters at each inlet. 3. Installation of a straw bale barrier at the outlet of the interim detention pond. 4. Installation of silt fences along the South and East boundary of the site. In ' addition, three silt fences will be installed in a Southwest to Northeast 1 1 1 1 direction at the Southeast area of the site. Silt fences will also be installed in the Northeast corner of the site. 5. Drill seed drought tolerant non -irrigated turf and hydro -mulched in undeveloped areas whether disturbed or not. The Contractor will be required to furnish a temporary, above ground method of irrigation to supplement natural precipitation in order to insure proper germination of seed during June through August. 6. Landscaping in parking islands, walkways and other open developed areas. The cost estimates for the erosion control measures are as follows: Erosion Control Cost Estimate No. Item Qtv Unit Unit Cost Total Comments 1. Drill seed with drought tolerant non - irrigated turf. 8.8 Ac. $ 650.00 $ 5,720.00 S0.0149/s.f. 2. Inlet gravel filter 10 Ea. 300.00 3,000.00 3. Silt fence 3920 L.F. 3.00 17,760.00 Construction Cost $20,480.00 50% of Construction Cost 10,240.00 Total Security $30,720.00 City Reseeding Cost 1. Reseeding 20 Ac. 500.00 $70,000.00 $0.0115/s.f. Construction Cost 70,000.00 50% of Construction Cost 5,000.00 Total Security $15,000.00 APPENDIX EROSION CONTROL EVALUATION 1�llhGb a /O©'� �pd��stTE.. 2 . D6 vE ,wE�IT PC�Ib< 5S Aeiq 7PI /c-,GRocfKY sTo,e664 GFJl�fyiE�G/+4L_ /Ic. .�ET�I�-/ IZE5T.4cl.�A�/T i4 u7-0MoT/vE aTe-) S 4 ODES /c! SE ,OiREc riati! 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G� > 3�1o¢b �o ,gbb� ��b/�i�T.4T<oa1 VOL I U I ® RAINFALL PERFORMANCE STANDARD EVALUATION PROJECT:PU-b 4L8E,27ZOAU STANDARD FORM A COMPLETED BY: pm f%16 as DATE: DEVELOPED ERODIBILITY Asb Lsb Ssb Lb Sb PS SUBBAgIN ZONE (ac) (ft) M (feet) (�) m re 4.440 ,6vG Q %�� 13,2a /4Da Siva = :9, /op� � _ o..G��%' �gp5ia4 Gj�/Jb 6140 S= 79,2 -72� 4a (D,40 D,`75 �9.(o6- C 3zo ` DLO C' � 0� /D (ai75) 9io t zee dye 5= So,3z �s,rr�. 1, 9/, n Dj 39 i5 P21 MQftI1.Y /D SAYE U 5� fog f 7o 0(61+0) 4-96(Of (13,zo 4 1/14 zo t , l4c) 7L 41 if 31 (.13,2g) f'C%/j((p,1J //✓�(DI ��^ Air / /� MARCH 1991 B•14 DESIGN CRITERIA I I I II I I I I I,.I I I 1 I I I IO = EFFECTIVENESS CALCULATIONS PROJECT: CAC^olrEV 5/zo Poo, (Ac-rc-OFTS0 STANDARD FORM B COMPLETED BY: pm m4`5rAf DATE: Erosion Control C-Factor P-Factor Method Value Value Cominent O'i0S/N . ____./i�----------�iS�---..----------------_._..--- .J�5+61�/MEAITA-T/oAJ ---- 7'72,4W QiILE RAQ,¢lER3�_�,�A�d�s_/�00rc ---.---- - f�SPs{4�_r,---------L.°�---- �ST,¢$G!5{�---- .flff; M U LCN MAJOR PS SUB AREA BASIN BASIN (Ac) CALCULATIONS Q � 74.E f�LMoS 13, 20 C- �AGTo R G,4 c-c S A'.r �2YG,44.10CrZa5S ; _ 7,o/ 53/, .�, G-F= 6.07 !3, � p-FAr,ro2 CALc`s, S'Eb 6prC4JEL F/L7EES) S�Li Fe,�GE P-f=Gl xo.aou D,�- Lam'• �2 ?' �4,ro AtmosT � A-o G- FAGra2 ceL.Ls . ALL. �S �QY Ldup GftAss= 2,�Z = 4f% ,', C-r= 6-1 6 40 A.8NALT 1ZVS, 6.1LLKs, ZLID = /.qG t/,&Z m 3,746L b,lo) +(3,74u Igo), �OZrr✓'/, P- f:Aro . G,�avEL I^IL.TEIZS , s�c-r >.EacE p-F= 0)$ Ko,S=40/, IMARCH 1991 9-15 DESIGN CRITERIA .1 1 1 1 1 1 EFFECTIVENESS CALCULATIONS PROJECT: GoUw,Ry G°cuQ Co2lj&,es STANDARD FORM B COMPLETED BY: DATE: / S Erosion Control C-Factor P-Factor Method Value Value. Comment MAJOR PS SUB AREA BASIN BASIN (Ac) CALCULATIONS W, 6 qLL 1 r39 C- �,4GT02 G � �r N ,�RYLa,Ub G2aS5 __ O�� = fD,3/, •', C-�:. 32� LAAjb5G.4P1A)4p dO39 j�S�t�bLT 1zv5� WALKS = v'35 "G p ,39 I�i•r19�� "�3ZbxD,S4�����46sc.75�t�39X,oZ�-�Z. 74k� © 6 PS = 741 / ' MARCH 1991 8-15 DESIGN CRITERIA Gt�/tib Leos<a� Go�uT/z�L s 'S'iTE rE vcvE »a ran, 91,7 4Fs.4 /y,� �lC �— c�.A.ze✓E2 r-E�cJGE rr� 6E /t✓Sr,4cc.U:4= f�-LONLa � � � Q�Utilv.4-ems'• ,4-�I7'7"/dAJ,4L G04•�Stb�1�f1`r/Dd.�. ;CEIJC, /ti! SW tiC— EC T77/ SE ,41z6 4 A/E GOR�lEiZ of s/ram. CONSTRUCTION SEQUENCE IROJECT: �C��UTRYGGu�c,ri2IJERSJ'�oPG/D(���ErzTsocrs� STANDARD FORM C EQUENCE FOR 19 9S ONLY COMPLETED BY: PM11145rSTAS DATE:96IJ456J-1W9!1-?1'1 ✓� gndicate 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 YEAR MONTH 1M A M OVERLOT GRADING I IIND EROSION CONTROL Soil Roughening Perimeter Barrier Additional Barriers Vegetative Methods Soil Sealant ' Other i RAINFALL EROSION CONTROL ' STRUCTURAL: Sediment Trap/Basin i Inlet Filters I Straw Barriers ' Silt Fence Barriers i Sand Bags � I Bare Soil Preparation I ' Contour Furrows Terracing i Asphalt/Concrete Paving i ' Other _ RM NE 7 A/-APR/d ?W _Dl?illvy _ T c 44 'VEGETATIVE: SE Any �E �j p /}EAS Permanent Seed Planting Mulching/Sealant 'Temporary Seed Planting Sod InstallationRM /JEN LLB OSG PE Nettings/Mate/Blankets i other ' I � � �RUCTURES: INSTALLED BY VEGETATION/MULCHING CONTRACTOR ITE SUBMITTED MAINTAINED BY APPROVED BY CITY OF FORT COLLINS ON 6iOoV77�1f674� WILL—#UIZ1C!/SH A 7-&rA-'702,4i?ty hCl VE_.la1QCUAJD ,4E7?f0-0 ' OF /.P2/Ers}Z�OJV .7t� SllF�PGjS7Er1lL_.N�ZL>R%a �-__ F'1c'GI P I T_ 6 T/0N.. _ ---�No2AE�e--T_p---h(SURE _Przop�2._.��,�Mi�cI�4Tia�! aF_ SEED. Im ' MARCH 1991 8-16 DESIGN CRITERIA