Chatham Park Stormwater Manual

Transcription

1 Chatham Park Stormwater Manual Table of Contents A. Introduction... 2 B. Calculation Methods... 2 C. BMP Design Standards... 3 D. Compliance Points... 3 E. Critical Environmental Resources... 3 F. Submittal Procedures... 4 G. Submittal Forms & Checklists... 4 Appendices: Appendix A: Sample BMP Supplement Forms Appendix B: Sample Stormwater Maintenance Manual Appendix C: Sample BMP Inspection Form Appendix D: Watershed Map Appendix E: Chatham Park Stormwater Exceptional Design Evaluation Appendix F: Chatham Park Standard Stormwater Design Drawings Chatham Park Residential Association 79 Hillsboro Street Pittsboro, NC 27312

2 A. INTRODUCTION This manual is a companion to Chatham Park PDD Master Plan, approved on August 10, 2015, the Chatham Park additional Elements, and applicable Town of Pittsboro stormwater regulations. The intent of this manual is to provide clarification and additional supporting documentation to assist development applicant in preparing and submitting stormwater management plans, and to provide guidance for long term maintenance of constructed stormwater management devices. This manual may be revised periodically to provide additional support and clarification, to stay current with industry trends and regulations, and to better assist project applicants. Revisions to this manual will be proposed by the Chatham Park Stormwater administrator and are subject to the approval of the Town Engineer. B. CALCULATION METHODS Peak Flow Chatham Park allows both the Rational Method and NRCS Curve Number for calculation of peak flow. Information regarding the Rational method can be found in Part B of the NCDENR Stormwater Design Manual and the City of Raleigh Stormwater Design Manual just to name two references. The NRCS Curve Number Method is described in more detail in Technical Report 55 (TR-55) Urban Hydrology for Small Watersheds, published by the USDA, and NRCS (June 1986). The Rational Method may be used to calculate peak flow when in watersheds less than or equal to 100 acres. (See Hydrology and Hydraulics below regarding use of the rational method for design of impoundments) The NRCS Curve Number Method is applicable to drainage areas of all sizes, but the Discrete NRCS Curve Number Method should be used to compute runoff volume for small drainage areas under 50 acres. The Discrete Curve Number Method is explained in Part B of the NCDENR Stormwater Design Manual Runoff Volume In addition to the Discrete NRCS Curve Number method, the Simple Method may be used to compute runoff volume when documenting compliance with BMP sizing requirements. The Rational Method may not be used to compute runoff volume without the written consent of the Chatham Park Stormwater Program Manager. Hydrology and Hydraulics Conveyance Systems (pipes, culverts, swales) Proper design of stormwater conveyance systems is critical in reducing flood risks and ensuring public the design rainfall intensity are adequate to size a system but as watersheds get larger more complex multi-nodal models incorporating watershed timing may be necessary to design the system. It is the design engineer s responsibility to choose a proper modeling technique and applicable software programs to complete the necessary calculations in accordance with standard engineering practices. The rational method or the NRCS Curve Number Method may be used for pipe and conveyance system Stormwater Control Measures Compliance with Chatham Park and Town of Pittsboro stormwater quality and flood control regulations may require the design and construction of impoundments to control the increase in stormwater runoff volume and peak flow resulting from rainfall events. Due to the impoundment area versus time. The design of BMPs often requires the use of hydrologic modeling software. The design engineer should choose appropriate software capable of analyzing complex inflow hydrographs and modeling the impact of storage Chatham Park Stormwater Design Manual 6/28/17 Page 2

3 impoundments and their outlet structures to generate an outflow hydrograph. All BMP designs must be signed and sealed by an NC registered Professional Engineer or other qualified professional (refer to your licensing board for guidance if you are unsure if your professional credentials are suitable for BMP design). All BMPs where the sizing and performance analysis is based on a routing of available volume in the impoundment at a given time step requires the development of hydrographs. All hydrographs shall be developed using the methods explained in TR-55. BMP where the minimum design criteria are based solely on peak flow rate (ie swales, disconnected impervious area etc.) may be designed using other applicable and acceptable calculations methods. C. BMP DESIGN STANDARDS Stormwater BMPs approved for use by NCDEQ, NCDOT, or the Town of Pittsboro may be used within Chatham Park for the express purpose of complying with the performance requirements of the Stormwater Standards or other applicable Town, State, or Federal stormwater management regulations enforced within Chatham Park. In addition to the devices approved by the Town of Pittsboro and those included in the most recent version of the NCDEQ Stormwater Design Manual, the following BMP designs have been approved for use within Chatham Park. (Note: the final design standards of all BMPs shall be approved by the Chatham Park Stormwater Program Manager and the Town of Pittsboro Stormwater Administrator) Roadside Tree Well (See Appendix A) NCDOT Roadside Tree Well Details, design criteria, and general design guidance can be found in the D. COMPLIANCE POINTS As stated in the Master Plan and Stormwater Element, compliance with the Stormwater Standards may be met onsite or on a sub-watershed level. Applicants should note that projects and watershed may have multiple points of compliance based on various regulations included in the Stormwater Standards. Points of compliance should be discussed during the pre-application meeting based on project design components and specific applicable regulations. For example, flood control and peak flow regulations may be complied with on the watershed level, but it may be necessary to design and construct BMPs upstream of new stormwater conveyances through the regulated buffer to comply with the requirements of the RBPO. The Chatham Park Stormwater Manager is available assist applicants with identifying compliance points on each project based on site characteristics and applicable regulations. Compliance with Stormwater Standards on a sub-watershed level does not alter the requirement to comply with other applicable stormwater standard that are enforceable at a more local level. E. CRITICAL ENVIRONMENTAL RESOURCES The Stormwater Element defines Critical Environmental Resources as follows: perennial streams and intermittent streams as defined in the Master Plan. wetlands that are Waters of the U.S. under the federal Clean Water Act. waterbodies that are Waters of the U.S. under the federal Clean Water Act. 100 year floodplains as delineated on the effective flood insurance rate maps for Chatham County, North Carolina Chatham Park Stormwater Design Manual 6/28/17 Page 3

4 regulated buffers and additional buffers, as those terms are defined in the Master Open Space Plan Additional Element tree canopy, in accordance with the Exceptional Design Evaluation At a minimum, Tree Canopy at the watershed scale shall be determined based on 2013 aerial photography from NC One Map, or more detailed information as approved by the Chatham Park Stormwater Program Manager. Tree Canopy area delineations from aerial photography shall be supplemented and edited as necessary after Tree Coverage Inventory Field Reports are prepared and submitted on a project by project basis. Any questions regarding measurement, delineation, or qualification of an area as a Critical Environmental Resource shall be directed to the Chatham Park Stormwater Program Administrator. Any adjustments form the standards described above are subject to approval by the Chatham Park Stormwater Program Manager and the Town of Pittsboro Stormwater Administrator. F. CHATHAM PARK STORMWATER EXCEPTIONAL DESIGN EVALUATION Appendix F contains the user s manual for the Chatham Park Stormwater Exceptional Design Evaluation. At a minimum, sub watersheds within Chatham Park shall maintain an evaluation score of 100 points to maintain compliance with the commitment to protection of critical environmental resources as described in the Stormwater Element. G. SUBMITTAL PROCEDURES Plan submittals shall comply with the requirements of section 203 of the current Town of Pittsboro, NC Stormwater Ordinance for New Development and Redevelopment in the Jordan Lake Watershed. The concept plan and consultation meeting may be conducted by the Chatham Park Design Review Committee or its designated representative. The Natural Resources inventory may be replaced with maps and data sheets required for completion of the Chatham Park Watershed Resiliency Evaluation documented in this manual The applicant shall provide a Town of Pittsboro Stormwater Management Application and all applicable items from the Permit Application checklist, including fees. If the applicant chooses to use a watershed level analysis to document compliance with peak flow control and watershed scoring requirements, the applicant shall submit summaries of those analyses to the Chatham Park Stormwater Program Manager. The Chatham Park Stormwater Program Manager shall provide updated summaries for watershed scale compliance elements when applicable (peak flow, watershed resiliency evaluation, and nutrient loading) to accompany individual plan submittals. H. SUBMITTAL FORMS & CHECKLISTS All submittals shall be accompanied by a Stormwater Discharge Permit Submittal Checklist copies of which can be found in Appendix D of the Town of Pittsboro Stormwater Administrative Manual. All items in the checklist shall be included with each submittal unless that item is not applicable to the site design, or the Town Stormwater Administrator has granted an exception from the submittal requirements. Chatham Park Stormwater Design Manual 6/28/17 Page 4

5 The stormwater report, required per the checklist, shall include a summary statement, or statements, documenting compliance with applicable Stormwater Standards, including a peak flow summary table and completed Chatham Park Stormwater Exceptional Design Evaluation form. Supplement forms (Appendix A), shall be submitted for each proposed BMP. Chatham Park Stormwater Design Manual 6/28/17 Page 5

6 APPENDIX A: Sample BMP Supplement Forms Note: Contact the Chatham Park Stormwater Program Manager to obtain electronic copies and fillable forms. 6/28/17 Chatham Park Stormwater Design Manual

7 SUPPLEMENT FORM COVER PAGE Please indicate the types, quantities and locations of SCMs that will be used on this project: Quantity Infiltration System 1 Bioretention Cell 1 Wet Pond 1 Stormwater Wetland 1 Permeable Pavement 1 Sand Filter 1 Rainwater Harvesting 1 Green Roof 1 Level Spreader-Filter Strip 1 Disconnected Impervious Surface 1 Treatment Swale 1 Dry Pond 1 Location(s) Project Name: EXAMPLE for SW Manual Address Chatham Park Watershed Designer information for this project: Name and Title: Organization: Street address: City, State, Zip: Phone number(s): Property Owner / Developer Company: Contact: Mailing Address: City, State, Zip: Phone number(s): Designer Certification Statement: I certify, under penalty of law: that this Supplement-EZ form and all supporting information were prepared under my direction or supervision; - that the information provided in the form is, to the best of my knowledge and belief, true, accurate, and complete; and Seal Signature of Designer Date - that the engineering plans, specifications, operation and maintenance agreements and other supporting information are consistent with the information provided here. I am aware that there are significant penalties for submitting false information including the possibility of fines and imprisonment for knowing violations as well as a report being made to my professional board. Cover Page 1 8:57 AM 6/27/2017

8 INFILTRATION SYSTEMS THE DRAINAGE AREA Drainage area number Total coastal wetlands area (sq ft) - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area Total BUA (sq ft) COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Stormwater program(s) that apply (please specify): GENERAL MDC FROM 02H.1050 Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? INFILTRATION SYSTEM MDC FROM 02H.1051 #1 SHWT elevation (fmsl) #5 Length (ft) #1 Was the soil investigated in the footprint and at the elevation of the infiltration system? #5 Width (ft) #1 Soil infiltration rate (in/hr) #5 Depth/Height (ft) #1 Briefly describe the hydraulic properties and characteristics of the soil profile: Break down of BUA in the drainage area (both new and existing): #5 Surface area of the bottom of the infiltration system (sq feet) #5 Ponding depth of the design volume (in) #5 Estimated dewatering time (hours) #5 For trenches only: Perforated pipe diameter, if applicable (inches) #2 SHWT elevation (fmsl) #5 For trenches only: Number of laterals #2 Bottom of the Infiltration system (fmsl) #5 For trenches only: Stone type, if applicable #2 Is a detailed hydrogeologic study attached if the separation is between 1 and 2 feet? #5 For trenches only: Stone void ratio (%) #3 Proposed slope of the subgrade surface (%) #5 For trenches only: Is stone free of fines? #3 Are terraces or baffles provided? #5 For trenches only: Is the stone wrapped in geotextile fabric? #4 Describe the pretreatment that will be provided: #6 Is the infiltration system located underground? #6 If so, has at least one infiltration port been provided? ADDITIONAL INFORMATION Please use this space to provide any information about this infiltration system that you think is relevant to the review: EXAMPLE for SW Manual 1 Infiltration 2 8:57 AM 6/27/2017

9 BIORETENTION CELL THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area Total BUA (sq ft) COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? BIORETENTION CELL MDC FROM 02H.1052 #1 SHWT elevation (fmsl) #6 Percentage of medium to coarse washed sand by volume #1 Bottom of the bioretention cell (fmsl) #6 Percentage of fines (silt and clay) by volume #1 Distance from bottom to SHWT (feet) #6 Percentage of organic matter by volume #2 Surface area of the bioretention cell (square feet) #6 Type of organic material #2 Design volume of the bioretention cell (cubic feet) #7 Phosphorus Index (P-Index) of media (unitless) #2 Ponding depth of the design storm (inches) #8 Will compaction be avoided during construction? #3 Is the bioretention cell used for peak attenuation? #9 Will cell be maintained to a one inch/hour standard? #3 Depth of peak attenuation over planting surface (in) #10 Describe the planting plan: #3 Height of peak attenuation outlet above the planting surface (in) #4 Infiltration rate of the in situ soil (inch/hour) #4 Diameter of the underdrain pipes (if applicable) #4 Does the design include Internal Water Storage (IWS)? #11 Depth of mulch, if applicable (inches) #4 if so, elevation of the top of the IWS (fmsl) #11 Type of mulch, if applicable #4 Elevation of the planting surface (fmsl) #12 How many clean out pipes are being installed? #5 Will the cell contain trees and shrubs? #12 Briefly describe the pretreatment that will be used: #5 Media depth (inches) ADDITIONAL INFORMATION Please use this space to provide any additional information about this bioretention cell that you think is relevant to the review: EXAMPLE for SW Manual Bioretention 3 8:57 AM 6/27/2017

10 WET POND THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area Total BUA (sq ft) COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? WET POND MDC FROM 02H.1053 #1 Method used #6 Width of the vegetated shelf (feet) #1 Surface area of the main permanent pool (square feet) #6 Location of vegetated shelf #1 Volume of the main permanent pool (cubic feet) #6 Elevation of top of shelf (fmsl) #2 Average depth of the main pool (feet) #6 Elevation of bottom of shelf (fmsl) #2 Was the vegetated shelf included in the calculation of average depth? #6 Slope of vegetated shelf (H:V) #2 Elevation of the bottom of the permanent pool (fmsl) #7 Diameter of drawdown orifice (inches) #2 Elevation of the top of the permanent pool (fmsl) #7 Drawdown time for the temporary pool (hours) #2 Elevation of the top of the temporary pool (fmsl) #7 Does the orifice drawdown from below the top surface of the permanent pool? #3 Depth provided for sediment storage (inches) #8 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? #4 Are the inlet(s) and outlet located in a manner that avoids short-circuiting? #4 Describe any measures, such as berms or baffles, that will be taken to improve the flow path: #9 Are fountains proposed? #9 If yes, is documentation provided per Wet Pond MDC (9)? #10 Is a trash rack or other device provided to protect the outlet system? #5 Volume of the forebay (cubic feet) #11 Are the dam and embankment planted in non-clumping turf grass? #5 Is this 15-20% of the volume in the main pool? #11 Species of turf that will be used on the dam and embankment #5 Depth of forebay at entrance (inches) #11 Describe the planting plan for the vegetated shelf: #5 Depth of forebay at exit (inches) #5 Does water flow out of the forebay in a non-erosive manner? #5 Clean-out depth for forebay (inches) #5 Will the forebay be cleaned out when the depth is reduced to less than the above? ADDITIONAL INFORMATION Please use this space to provide any additional information about this wet pond that you think is relevant to the review: EXAMPLE for SW Manual Wet Pond 4 8:57 AM 6/27/2017

11 STORMWATER WETLAND THE DRAINAGE AREA Drainage area number Total coastal wetlands area (sq ft) - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Stormwater program(s) that apply (please specify): GENERAL MDC FROM 02H.1050 Total BUA (sq ft) Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? STORMWATER WETLAND MDC FROM 02H.1054 #1 Permanent pool elevation (fmsl) #8 Total surface area of the shallow water zone at temporary pool (square feet) #1 Temporary pool elevation (fmsl) #8 SW wetland surface area comprised of shallow water zone at temporary pool (%) #1 Ponding depth (inches) #8 Depth of the shallow water zone below permanent pool (inches) #2 Is the SW wetland designed for peak attenuation? #8 Elevation of bottom of the shallow water zone (fmsl) #2 If so, peak attenuation depth (inches) #9 Total surface area of the temporary inundation zone at temporary pool (square feet) #3 Surface area of SW wetland at temporary pool (square feet) #9 SW wetland surface area comprised of temp inundation zone at temp pool (%) #4 Depth of soil amendment (inches) #9 Height of the temporary inundation zone above permanent pool (inches) #4 Describe how the soil is being amended to promote plant growth: #9 Elevation of bottom of the temporary inundation zone (fmsl) #10 Drawdown time for the temporary pool (hours) #10 Does the orifice drawdown from below the top surface of the permanent pool? #11 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? #6 Are the inlet(s) and outlet located in a manner that avoids short-circuiting? #12 Has a landscaping plan that meets SW Wetland MDC (12) been provided? #6 Describe any measures, such as berms or baffles, that will be taken to improve the flow path: #6 Surface area of the forebay at temporary pool (square feet) #6 Overall SW wetland surface area comprised of forebay at temporary pool (%) #13 Number of plants per 200 square feet (#) in the shallow water zone: #6 Depth of forebay below permanent pool (inches) #14 Does planting for the temporary inundation zone comply with SW Wetland MDC (14)? #6 Elevation of bottom of forebay (fmsl) #14 Describe the planting plan for the temporary inundation zone: #6 Will the forebay be cleaned out when depth is reduced to 15 inches or less? 1 #7 Total surface area of the non-forebay deep pools at temporary pool (square feet) Break down of BUA in the drainage area (both new and existing): #13 Describe the planting plan for the shallow water zone: 1 #7 SW wetland surface area comprised of non-forebay deep pools at temporary pool (%) #15 Are the dam structure and temporary fill slopes planted in non-clumping turfgrass? #7 Depth of non-forebay deep pools below permanent pool (inches) #16 Will cattails be planted in the wetland? #7 Elevation of bottom of non-forebay deep pools (fmsl) #17 Is a trash rack or other device provided to protect the outlet system? ADDITIONAL INFORMATION Please use this space to provide any information about this stormwater wetland that you think is relevant to the review: EXAMPLE for SW Manual 1 Wetland 5 8:57 AM 6/27/2017

12 PERMEABLE PAVEMENT THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? PERMEABLE PAVEMENT MDC FROM 02H.1055 #1 Was the soil investigated in the footprint and at the elevation of the infiltration system? #6 How will the pavement surface be tested? #1 Briefly describe the hydraulic properties and characteristics of the soil profile: EXAMPLE for SW Manual #7 Area of permeable pavement to be installed (square feet) #7 Area of screened roof runoff that is directed to pavement (square feet) #2 SHWT elevation (fmsl) #7 Area of additional built-upon area runoff that is directed to pavement (square feet) #2 Top of the subgrade (fmsl) #7 Will runoff from pervious surfaces be directed away from the pavement? #2 Storage elevation of the design rainfall depth (fmsl) #8 Dewatering time (hours) #2 Is a detailed hydrogeologic study attached if the separation is between 1 and 2 feet? #8 Is additional media being added to the soil profile? #3 Will toxic pollutants be stored or handled on or near the permeable pavement? #9 Is at least one observation well per terrace been provided at the low point(s)? #4 Proposed slope of the subgrade surface (%) #10 Is this a detention permeable pavement system? #4 Are terraces or baffles provided? #10 If so, what is the drawdown time for the design storm? #5 Size of aggregate to be used in the subbase #11 Have edge restraints been provided? #5 Aggregate depth (in) #12 Will the subgrade be graded when dry? #5 Aggegate porosity (n) #13 Will the permeable pavment be protected from sediment during construction? #5 Will the aggregate be washed? #13 Will an in-situ permeability test be conducted after site stabilization ADDITIONAL INFORMATION Please use this space to provide any additional information about this permeable pavement design that you think is relevant to the review: Permeable Pavement 6 8:57 AM 6/27/2017

13 SAND FILTER THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? SAND FILTER MDC FROM 02H.1056 #1 SHWT elevation (fmsl) #3 Volume of stormwater from drainage area during design storm (cubic feet) #1 Type of sand filter (open or closed) #3 Total volume that can be stored above the sediment and sand chambers (cubic feet) #1 If closed, describe if the filter will be pre-cast or pour-in-place: #3 Is this sand filter designed to attenuate peak flows? #3 Elevation of the bypass device (fmsl) #1 If closed, top of grate elevation (fmsl) #2 Volume that can be retained in the sediment chamber (cubic feet) #2 Will there be a permanent pool in the sediment chamber? #2 Bottom of the sediment chamber (fmsl) #3 Describe the bypass device: #4 Ponding depth from the top of the sand to the bypass device (ft) #2 Area of the sediment chamber (square feet) #2 Physical depth of the sediment chamber (inches) #2 Ponding depth in the sediment chamber, above any permanent pool (inches) #2 Elevation of top of weir between chambers (fmsl) #2 Volume that can be retained in the sand chamber (cubic feet) #2 Bottom of the sand chamber (fmsl) #5 Describe the mechanism for distributing flow over the sand surface: #6 Sand specification for sand chamber #7 Depth above underdrain pipe (inches) #2 Area of the sand chamber (square feet) #8 Will the media be maintained to drain at least two inches per hour at the sand surface? #2 Physical depth of the sand chamber (inches) #9 Is at least one clean-out pipe provided at the low point of each underdrain line? #2 Ponding depth in the sand chamber, above any permanent pool (inches) #9 Will clean-out pipes be capped? ADDITIONAL INFORMATION Please use this space to provide any additional information about this sand filter that you think is relevant to the review: EXAMPLE for SW Manual Sand Filter 7 8:57 AM 6/27/2017

14 RAINWATER HARVESTING SYSTEM (RWH) THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? RWH MDC FROM 02H.1057 #1 Collection system for the RWH #2 Will the RWH be used to meet a water usage requirement? #1 Describe the pre-treatment system for the RWH: #2 If so, describe the water usage for the RWH: EXAMPLE for SW Manual #1 Size of cistern (gallons) #2 Does cistern include a passive discharge? #1 Height of cistern (feet) #2 If so, describe the passive discharge (diameter, height and discharge location): #1 Location of cistern #1 Cistern material #1 Describe the overflow system for the RWH: #3 Percentage of the total annual runoff that will be handled by the RWH (%) #4 Was NCSU's Water Harvester Model used for the calculations? #1 Describe the distribution system for the RWH: #5 Will the RWH system be tested for functionality prior to use? #5 Will additions to the RWH system be tested for functionality prior to use? #6 Will all outlets and appurtenances be labeled as Non-Potable Water? #1 Who will be responsible for operating and maintaining the RWH?: #6 Will all passive drawdown devices be marked with identifying signage? #5 Will additions to the RWH system be tested for functionality prior to use? ADDITIONAL INFORMATION Please use this space to provide any additional information about this RWH that you think is relevant to the review: RWH 8 8:57 AM 6/27/2017

15 GREEN ROOF THE DRAINAGE AREA Drainage area number 1 Break down of BUA in the drainage area (both new and existing): Total coastal wetlands area (sq ft) - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? GREEN ROOF MDC FROM 02H.1058 #1 Describe the media that will be used for the green roof: #3 Depth of media (inches) #4 Is the planting plan designed for 75% cover within 2 years? #4 Describe the green roof planting plan: EXAMPLE for SW Manual #1 Percent organic fraction by volume (%) #2 Plant available water in the media (#) #2 Rainfall depth treated by the green roof (inches) #5 Slope of the green roof (%) ADDITIONAL INFORMATION Please use this space to provide any additional information about this green roof that you think is relevant to the review: Green Roof 9 8:57 AM 6/27/2017

16 LEVEL SPREADER - FILTER STRIP (LS-FS) THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? LS-FS MDC FROM 02H.1059 #1 Length of level spreader (feet) #7 Height of the drop from the level spreader to the transition zone (inches) #2 LS-FS receives flow from #7 Width of the transition zone (inches) #2 Flow rate to LS-FS during design storm (cfs) #7 Protection for the transition zone #2 Is a bypass device provided? #2 If yes, describe the bypass device: #8 Width of the filter strip (feet) #9 Is the filter strip free of draws and channels? #9 Has this been verified in the field? #3 Is this LS-FS designed to receive flow from the drainage area during the 10-year storm? #10 Slope of the filter strip (%) #4 Has a blind swale been provided? #10 Is this slope uniform across the entire filter strip? #4 Does the blind swale provide for uniform overtopping of the level spreader? #10 Will the first 12" of soil be adjusted if needed to promote plant growth? #5 What material will be used for the level spreader? #10 Will the filter strip and side slopes be planted with non-clumping, deep-rooted sod? #5 Will the construction tolerance be < 0.25 inch along the level spreader length? #10 Species of sod that will be used #6 Will the level spreader be straight or convex in plan view? #10 Will soil be temporarily stabilized until permanent vegetation is established? ADDITIONAL INFORMATION Please use this space to provide any additional information about this LS-FS that you think is relevant to the review: EXAMPLE for SW Manual LS-FS 10 8:57 AM 6/27/2017

17 DISCONNECTED IMPERVIOUS SURFACES (DIS) THE DRAINAGE AREA Drainage area number Total coastal wetlands area (sq ft) - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Stormwater program(s) that apply (please specify): GENERAL MDC FROM 02H.1050 Total BUA (sq ft) Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance (drop down)? #13 Was the SCM designed by an NC licensed professional? DIS MDC FROM 02H.1060 #1 Maximum roof area that will be conveyed to the VRA (fmsl) #3 Hydrologic Soil Group of VRA #1 Will the VRA be rectangualar in shape? #3 Slope of the VRA in the direction of flow (%) #1 Length of the rectangle in the direction of flow (feet) #3 Will the first 8" of soil be adjusted if needed to promote plant growth? #1 Width of the rectangle perpendicular to the direction of flow (feet) #3 Will the filter strip and side slopes be planted with non-clumping, deep-rooted sod? #1 Will the downspouts be equipped with splash pads? #2 Length of pavment draining to the VRA (feet) #2 Width of the VRA (feet) #2 Is the VRA free of BUA except for utility boxes, signs signs, and lamp posts? ADDITIONAL INFORMATION Please use this space to provide any additional information about this DIS that you think is relevant to the review: Break down of BUA in the drainage area (both new and existing): EXAMPLE for SW Manual #3 Describe how the DIS will be protected from erosion until permanent ground cover has taken root: 1 DIS 11 8:57 AM 6/27/2017

18 TREATMENT SWALE THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? TREATMENT SWALE MDC FROM 02H.1061 #1 SHWT elevation (fmsl) #4 Species of grass that will be used #1 Bottom of the treatment swale (fmsl) #4 Will the grass be maintained at an average height of 6 inches? #2 Depth of treatment swale (feet) #4 Will the grass not be cut lower than 4 inches? #2 ls swale trapezoidal in shape? #5 Velocity during the 10-year storm (feet per second) #2 Width of bottom of swale (feet) #5 Describe measures that will be taken to prevent erosion during the 10-year storm: #2 Side slopes of treatment swale (H:V) #3 Length of swale (feet) #3 Flow depth during the 0.75 inch/hour storm (inches) #3 Velocity during the 0.75 inch/hour storm (feet per second) #3 Hydraulic retention time for swale (minutes) ADDITIONAL INFORMATION Please use this space to provide any information about this treatment swale that you think is relevant to the review: EXAMPLE for SW Manual TrSwale 12 8:57 AM 6/27/2017

19 DRY POND THE DRAINAGE AREA 1 Drainage area number Total coastal wetlands area (sq ft) Break down of BUA in the drainage area (both new and existing): - Parking / driveway (sq ft) Total surface water area (sq ft) - Sidewalk (sq ft) Total drainage area (sq ft) - Roof (sq ft) BUA associated with existing development (sq ft) - Roadway (sq ft) Proposed new BUA (sq ft) - Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM Total BUA (sq ft) Stormwater program(s) that apply (please specify): Design rainfall depth (in) Minimum volume required (cu ft) Design volume of SCM (cu ft) GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build-out? #7 If applicable, with the SCM be cleaned out after construction? #2 Is the SCM located on or near contaminated soils? #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H:V)? #9 Does the drainage easement comply with General MDC (9)? #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? #4 Are the inlets, outlets, and receiving stream protected from erosion (10-year storm)? #11 Is there an O&M Agreement that complies with General MDC (11)? #5 Is there a a bypass for flows in excess of the design flow? #12 Is there an O&M Plan that complies with General MDC (12)? #6 What is the method for dewatering the SCM for maintenance? #13 Was the SCM designed by an NC licensed professional? DRY POND MDC FROM 02H.1062 #1 SHWT elevation (fmsl) #5 Describe the pretreatment that will be provided for the dry pond: #1 Elevation of the bottom of the dry pond (fmsl) #1 Distance from bottom to SHWT (feet) #6 Size of drawdown orifice (in) #2 Elevation of the temporary pool during the design storm (feet) #6 Drawdown time for the temporary pool (hours) #2 Ponding depth of the design storm (feet) #7 Does the pond minimize impacts to the receiving channel from the 1-yr, 24-hr storm? #3 Will the dry pond be uniformly graded to flow toward the outlet? #8 Is there a small permantent pool near the orifice to prevent clogging? #3 Is a low flow channel being provided? #4 Are the inlet(s) and outlet located in a manner that avoids short-circuiting? #8 Describe how the outlet will be designed to prevent clogging: #4 Describe any measures, such as berms or baffles, that will be taken to increase the flow path: #9 Are the dam and embankment planted in non-clumping turf grass? #9 Species of turf that will be used on the dam and embankment #9 Will trees and shrubs be prevented from growing on the dam and embankment? ADDITIONAL INFORMATION Please use this space to provide any additional information about this dry pond that you think is relevant to the review: EXAMPLE for SW Manual Dry Pond 13 8:57 AM 6/27/2017

20 APPENDIX B: Sample BMP Operation and Maintenance Manual Note: Contact the Chatham Park Stormwater Program Manager to obtain electronic copies and fillable forms. 6/28/17 Chatham Park Stormwater Design Manual

21 Operation & Maintenance Manual Project Name: Location: Cover Page Maintenance records shall be kept on each of the following BMP(s). This maintenance record shall be kept In a log and made available for review by the Town of Pittsboro upon request. Any deficient BMP elements noted in the inspection shall be corrected, repaired, or replaced as soon are reasonably practicable at the expense of the Chatham Park Residential Association, Inc. (the "Association"). As provided in the Chatham Park Master Stormwater Plan Additional Element, a major repair to a BMP is one for which the cost is equal to or greater than one-third (1/3) of the then replacement cost of that BMP. The BMP(s) on this project include (check all that apply & corresponding O&M forms will be added automatically): Bioretention Cell Quantity: 1 Location(s): Dry Detention Basin Quantity: 1 Location(s): Grassed Swale Quantity: 1 Location(s): Green Roof Quantity: 1 Location(s): Infiltration Basin Quantity: 1 Location(s): Infiltration Trench Quantity: 1 Location(s): Level Spreader/VFS Quantity: 1 Location(s): Permeable Pavement Quantity: 1 Location(s): Proprietary System Quantity: 1 Location(s): Rainwater Harvesting Quantity: 1 Location(s): Sand Filter Quantity: 1 Location(s): Stormwater Wetland Quantity: 1 Location(s): Wet Detention Basin Quantity: 1 Location(s): Disconnected Impervious Area Present: Yes Location(s): Tree Wells Quantity: 1 Location(s): User Defined BMP Present: Yes Location(s): In accordance with the Master Stormwater Agreement for Chatham Park, recorded in the office of the Register of Deeds for Chatham County, North Carolina, in Book, Page, the Association is responsible for completing annual inspections and having maintenance procedures performed on each of the BMPs identified above, in accordance with the recommendations and requirements in this Manual. This Manual has been reviewed and accepted by the Chatham Park Residential Association by, (Title) Signature: Date: Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 1 of 27

22 Bioretention Maintenance Requirements CONTACT THE CHATHAM PARK STORMWATER PROGRAM MANAGER IMMEDIATELY IF PONDED WATER REMAINS FOR MORE THAN 2 DAYS OR IF THE DAM OR OUTLET STRUCTURE HAVE FAILED Important operation and maintenance procedures: Immediately after the bioretention cell is established, the plants will be watered twice weekly if needed until the plants become established (commonly six weeks). Snow, mulch or any other material will NEVER be piled on the surface of the bioretention cell. Wheeled or tracked equipment will NEVER be driven over the bioretention planting surface. Special care will be taken to prevent sediment from entering the bioretention cell. If standing water is present 2 days after rainfall, contact the Chatham Park Stormwater Program Manager After the bioretention cell is established, the Residential Association will inspect all items listed below annually and prepare and inspection report. Required maintenance will be coordinated with the Property Owner. BMP element: Potential problem: How to remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the BMP Areas of bare soil and/or Regrade the soil to remove the gully, and plant a ground cover and erosive gullies have formed. water until it is established. Provide lime and a one-time fertilizer application. Vegetation is too short or too Maintain vegetation at a height of approximately six inches. long. The inlet device The pipe is clogged. Unclog the pipe. Dispose of the sediment off-site. The pipe is cracked or otherwise damaged. Replace the pipe. The pretreatment area The bioretention cell: vegetation Erosion is occurring in the swale. Stone verge is clogged or covered in sediment (if applicable). Flow is bypassing pretreatment area and/or gullies have formed. Sediment has accumulated to a depth greater than three inches. Erosion has occurred. Weeds are present. Best professional practices show that pruning is needed to maintain optimal plant health. Plants are dead, diseased or dying. Tree stakes/wires are present six months after planting. Regrade the swale to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems. Remove sediment and replace with clean stone. Regrade if necessary to route all flow to the pretreatment area. Restabilize the area after grading. Search for the source of the sediment and remedy the problem if possible. Remove the sediment and restabilize the pretreatment area. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Remove the weeds, preferably by hand. Prune according to best professional practices. Determine the source of the problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. Remove tree stake/wires (which can kill the tree if not removed). Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 2 of 27

23 Bioretention Maintenance Requirements (continued) BMP element: The bioretention cell: soils and mulch Potential problem: Mulch is breaking down or has floated away. How to remediate the problem: Spot mulch if there are only random void areas. Replace whole mulch layer if necessary. Remove the remaining much and replace with triple shredded hard wood mulch at a maximum depth of three inches. Soils and/or mulch are clogged with sediment. An annual soil test shows that ph has dropped or heavy metals have accumulated in the soil media. Determine the extent of the clogging - remove and replace either just the top layers or the entire media as needed. Dispose of the spoil in an appropriate off-site location. Use triple shredded hard wood mulch at a maximum depth of three inches. Search for the source of the sediment and remedy the problem if possible. Major maintenance may be required. Dolomitic lime shall be applied as recommended per the soil test and toxic soils shall be removed, disposed of properly and replaced with new planting media. The underdrain system (if applicable) The receiving water Clogging has occurred. Erosion or other signs of damage have occurred at the outlet. Wash out the underdrain system. The drop inlet Clogging has occurred. Clean out the drop inlet. Dispose of the sediment off-site. The drop inlet is damaged Repair or replace the drop inlet. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 3 of 27

24 Dry Detention Pond Maintenance Requirements CONTACT THE CHATHAM PARK STORMWATER PROGRAM MANAGER IMMEDIATELY IF PONDED WATER REMAINS FOR MORE THAN 2 DAYS OR IF THE DAM OR OUTLET STRUCTURE HAVE FAILED Important maintenance procedures: The drainage area will be managed to reduce the sediment load to the dry extended detention basin. Immediately after the dry extended detention basin is established, the vegetation will be watered twice weekly if needed until the plants become established (commonly six weeks). No portion of the dry extended detention pond will be fertilized after the first initial fertilization that is required to establish the vegetation. The vegetation in and around the basin will be maintained at a height of approximately six inches. If cracks, seepage, or woody vegetation is present, consult a dam safety expert for a dam inspection. The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. After the dry detention basin is established, it will be inspected annually. Inspection activities shall be performed as follows and any problems identified will be remediated immediately per the table below. BMP element: Potential problem: How to remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the BMP Areas of bare soil and/or Regrade the soil if necessary to remove the gully, and then plant a erosive gullies have formed. ground cover and water until it is established. Provide lime and a onetime fertilizer application. Vegetation is too short or too Maintain vegetation at a height of approximately six inches. long. The inlet device The pipe is clogged. Unclog the pipe. Dispose of the sediment off-site. The pipe is cracked or otherwise damaged. Replace the pipe. Erosion is occurring in the swale. Stone verge is clogged or Remove sediment and replace with clean stone. covered in sediment (if applicable). The forebay Trash/debris is present. Remove the trash/debris. Erosion has occurred or riprap is displaced. Weeds are present. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Remove the weeds, preferably by hand. If pesticides are used, wipe them on the plants rather than spraying. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 4 of 27

25 Dry Detention Pond Maintenance Requirements (continued) BMP element: The main treatment area The embankment The outlet device The receiving water Potential problem: How to remediate the problem: Sediment has accumulated Search for the source of the sediment and remedy the problem if and reduced the depth to 75% possible. Remove the sediment and dispose of it in a location where it of the original design depth will not cause impacts to streams or the BMP. Revegetate disturbed (per pond design data sheet) areas immediately with sod (preferred) or seed protected with securely staked erosion mat. Water is standing more than 5 days after a storm event. Weeds and noxious plants are growing in the main treatment area. Shrubs or trees have started to grow on the embankment. Grass cover is unhealthy or eroding. Signs of seepage on the downstream face. Evidence of muskrat or beaver activity is present. Check outlet structure for clogging. If it is a design issue, consult an appropriate professional. Remove the plants by hand or by wiping them with pesticide (do not spray). Remove shrubs or trees immediately. Restore the health of the grass cover consult a professional if necessary. Consult a professional. Use traps to remove muskrats and consult a professional to remove beavers. An annual inspection by an Make all needed repairs. appropriate professional shows that the embankment needs repair. Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. Erosion or other signs of Contact the Chatham Park Stormwater Program Manager damage have occurred at the outlet. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 5 of 27

26 Pretreatment Has Veg. Filter DRY POND ID Yes Yes Dry Detention Pond Design Summary Dry Pond Diagram FOREBAY MAIN POND Temporary Pool El: Temporary Pool El: Clean Out Depth: 0 Clean Out Depth: 0 Sediment Storage El: Sediment Storage El: Bottom Elevation: Bottom Elevation: Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 6 of 27

27 Level Spreader-Vegetated Filter Strip / Restored Riparian Buffer Maintenance Requirements Important maintenance procedures: Immediately after the filter strip is established, any newly planted vegetation will be watered twice weekly if - needed until the plants become established (commonly six weeks). - Once a year, the filter strip will be reseeded to maintain a dense growth of vegetation - Stable groundcover will be maintained in the drainage area to reduce the sediment load to the vegetation Two to three times a year, grass filter strips will be mowed and the clippings harvested to promote the growth of thick vegetation with optimum pollutant removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and may be allowed to grow as tall as 12 inches depending on aesthetic requirements (NIPC, 1993). Forested filter strips do not require this type of maintenance. Once a year, the soil will be aerated if necessary. Once a year, soil ph will be tested and lime will be added if necessary. After the filter strip is established, it will be inspected annually. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the BMP The flow splitter device (if applicable) Areas of bare soil and/or erosive gullies have formed. Vegetation is too short or too long. The flow splitter device is clogged. The flow splitter device is damaged. The inlet device The pipe is clogged. Unclog the pipe. Dispose of the sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged. Erosion is occurring in the swale. Stone verge is clogged or covered in sediment (if applicable). Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Maintain vegetation at a height of approximately six inches. Unclog the conveyance and dispose of any sediment off-site. Make any necessary repairs or replace if damage is too large for repair. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Remove sediment and replace with clean stone. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 7 of 27

28 The receiving water LS-VFS / Restored Riparian Buffer Maintenance Requirements (Continued) The swale and the level lip The swale is clogged with sediment. The bypass channel The filter strip The level lip is cracked, settled, undercut, eroded or otherwise damaged. There is erosion around the end of the level spreader that shows stormwater has bypassed it. Trees or shrubs have begun to grow on the swale or just downslope of the level lip. Areas of bare soil and/or erosive gullies have formed. Turf reinforcement is damaged or ripap is rolling downhill. Grass is too short or too long (if applicable). Areas of bare soil and/or erosive gullies have formed. Sediment is building up on the filter strip. Plants are desiccated. Plants are dead, diseased or dying. Nuisance vegetation is choking out desirable species. Erosion or other signs of damage have occurred at the outlet. Remove the sediment and dispose of it off-site. Repair or replace lip. Regrade the soil to create a berm that is higher than the level lip, and then plant a ground cover and water until it is established. Provide lime and a one-time fertilizer application. Remove them. Regrade the soil if necessary to remove the gully, and then reestablish proper erosion control. Study the site to see if a larger bypass channel is needed (enlarge if necessary). After this, reestablish the erosion control material. Maintain grass at a height of approximately three to six inches. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Remove the sediment and restabilize the soil with vegetation if necessary. Provide lime and a one-time fertilizer application. Provide additional irrigation and fertilizer as needed. Determine the source of the problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application. Remove vegetation by hand if possible. If pesticide is used, do not allow it to get into the receiving water. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 8 of 27

29 Grassed Swale Maintenance Requirements CONTACT THE CHATHAM PARK POA IMMEDIATELY IF PONDED WATER REMAINS FOR MORE THAN 2 DAYS OR IF EROSION THREATERNS TO DAMAGE ADJACENT PROPERTY Important maintenance procedures: The drainage area of the grassed swale will be carefully managed to reduce the sediment load to the grassed - swale. - After the first-time fertilization to establish the grass in the swale, fertilizer will not be applied to the grassed The grassed swale will be inspected annually. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspections shall be performed annually. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remediate the problem: The perimeter of the BMP The entire length of the swale Areas of bare soil and/or erosive gullies have formed. Vegetation is too short or too Maintain vegetation at a height of approximately six inches. Trash/debris is present. Remove the trash/debris. Areas of bare soil and/or erosive gullies have formed. Sediment covers the grass at the bottom of the swale. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Regrade the soil if necessary to remove the gully, and then re-sod (or plant with other appropriate species) and water until established. Provide lime and a one-time fertilizer application. Remove sediment and dispose in an area that will not impact streams or BMPs. Re-sod if necessary. Vegetation is too short or too Maintain vegetation at a height of approximately six inches. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of damage have occurred at the outlet. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 9 of 27

30 Important maintenance procedures: - The drainage area will be carefully managed to reduce sediment load to the infiltration basin. Immediately after the infiltration basin is established, or as bare areas are repaired, the vegetation will be - watered twice weekly if needed until the plants become established (commonly six weeks). - - Infiltration System Maintenance Requirements CONTACT THE CHATHAM PARK POA IMMEDIATELY IF PONDED WATER REMAINS FOR MORE THAN 2 DAYS OR IF THE DAM OR OUTLET STRUCTURE HAVE FAILED No portion of the infiltration basin will be fertilized after the initial fertilization that is required to establish the vegetation. The vegetation in and around the basin will be maintained at a height of approximately six inches or as recommended for stable ground cover. After the infiltration basin is established, it shall be inspected annually. Records of operation and maintenance shall be kept in a known set location and shall be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to remove the gully, and then plant a infiltration basin erosive gullies have formed. ground cover and water until it is established. Provide lime and a onetime fertilizer application. Unclog the pipe. Dispose of the sediment off-site. The inlet device: pipe or swale The pipe is clogged (if applicable). The forebay The pipe is cracked or otherwise damaged (if applicable). Erosion is occurring in the swale (if applicable). Replace the pipe. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Sediment has accumulated Search for the source of the sediment and remedy the problem if and reduced the depth to 75% possible. Remove the sediment and dispose of it in a location where it of the original design depth. will not cause impacts to streams or the BMP. The main treatment area The embankment Erosion has occurred or riprap is displaced. Weeds are present. A visible layer of sediment has accumulated. Water is standing more than 5 days after a storm event. Weeds and noxious plants are growing in the main treatment area. Shrubs or trees have started to grow on the embankment. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Remove the weeds, preferably by hand. If pesticides are used, wipe them on the plants rather than spraying. Search for the source of the sediment and remedy the problem if possible. Remove the sediment and dispose of it in a location where it will not cause impacts to streams or the BMP. Replace any media that was removed in the process. Revegetate disturbed areas immediately. Replace the top few inches of filter media and see if this corrects the standing water problem. If so, revegetate immediately. If not, consult an appropriate professional for a more extensive repair. Remove the plants by hand or by wiping them with pesticide (do not spray). Remove shrubs or trees immediately. An annual inspection by an Make all needed repairs. appropriate professional shows that the embankment needs repair. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 10 of 27

31 The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of damage have occurred at the outlet. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 11 of 27

32 At all times, the pavement shall be kept free of: Debris and particulate matter through frequent blowing that removes such debris, particularly during the fall and - spring. - Piles of soil, sand, mulch, building materials or other materials that could deposit particulates on the pavement. - - Piles of snow and ice. Chemicals of all kinds, including deicers. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. The surface of the permeable pavement Permeable Pavement Maintenance Requirements The permeable pavement will be inspected annually. More frequent maintenance may be necessary to ensure proper function. Records of operation and maintenance will be kept in a known set location and will be available upon request. BMP element: Potential problem: How to remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the permeable pavement Areas of bare soil and/or erosive gullies Regrade the soil if necessary to remove the gully, then plant ground cover and water until established. A vegetated area drains toward the pavement. Erosion is occurring in the swale. Stone verge is clogged or covered in sediment (if applicable). Trash/debris present Weeds Sediment Rutting, cracking or slumping or damaged structure Regrade the area so that it drains away from the pavement, then plant ground cover and water until established. The inlet device The pipe is clogged. Unclog the pipe. Dispose of the sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Remove sediment and replace with clean stone. Remove the trash/debris. Do not pull the weeds (may pull out media as well). Spray them with a systemic herbicide such as glyphosate and then return within the week to remove them by hand. (Another option is to pour boiling water on them or steam them.) Vacuum sweep the pavement. Consult an appropriate professional. Observation well Water present more than five days after a storm event Clean out clogged underdrain pipes. Consult an appropriate professional for clogged soil subgrade. Educational sign Missing or is damaged. Replace the sign. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of damage have occurred at the outlet. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 12 of 27

33 Important maintenance procedures: - The drainage area will be carefully managed to reduce the sediment load to the sand filter. - The sedimentation chamber or forebay will be cleaned out whenever sediment depth exceeds six inches. - - Sand Filter Maintenance Requirements Once a year, sand media will be skimmed. The sand filter media will be replaced whenever it fails to function properly after maintenance. The sand filter shall be inspected annually. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remediate the problem: Entire BMP Trash/debris is present. Remove the trash/debris. Adjacent pavement (if Sediment is present on the Sweep or vacuum the sediment as soon as possible. applicable) pavement surface. Perimeter of sand filter Flow diversion structure The structure is clogged. Unclog the conveyance and dispose of any sediment offsite. The structure is damaged. Make any necessary repairs or replace if damage is too large for repair. The inlet device Forebay or pretreatment area Areas of bare soil and/or erosive gullies have formed. Vegetation is too short or too long. The pipe is clogged. The pipe is cracked or otherwise damaged. Erosion is occurring in the swale. Stone verge is clogged or covered in sediment (if applicable). Sediment has accumulated to a depth of greater than six inches. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Maintain vegetation at an appropriate height. Unclog the pipe. Dispose of the sediment off-site. Replace the pipe. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Remove sediment and replace with clean stone. Search for the source of the sediment and remedy the problem if possible. Remove the sediment and stabilize or dispose of it in a location where it will not cause impacts to streams or the BMP. Filter bed and underdrain collection system Erosion has occurred. Weeds are present. Water is ponding on the surface for more than 24 hours after a storm. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Remove the weeds, preferably by hand. If a pesticide is used, wipe it on the plants rather than spraying. Check to see if the collector system is clogged and flush if necessary. If water still ponds, remove the top few inches of filter bed media and replace. If water still ponds, then consult an expert. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of damage have occurred at the outlet. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 13 of 27

34 Stormwater Wetland Maintenance Requirements Important maintenance procedures: Immediately following construction of the stormwater wetland, bi-weekly inspections will be conducted and - wetland plants will be watered bi-weekly until vegetation becomes established (commonly six weeks). - No portion of the stormwater wetland will be fertilized after the first initial fertilization that is required to establish the wetland plants. - Stable groundcover will be maintained in the drainage area to reduce the sediment load to the wetland. - Once a year, a dam safety expert should inspect the embankment. After the stormwater wetland is established, it shall be inspected monthly and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How I will remediate the problem: Entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the BMP Areas of bare soil and/or erosive gullies have formed. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Vegetation is too short or too long. Maintain vegetation at a height of approximately six inches. Forebay The inlet device Sediment has accumulated in the forebay to a depth that inhibits the forebay from Erosion has occurred. Weeds are present. The pipe is clogged. The pipe is cracked or otherwise damaged. Erosion is occurring in the swale. Stone verge is clogged or covered in sediment (if applicable). Search for the source of the sediment and remedy the problem if possible. Remove the sediment and dispose of it in a location where it will not cause impacts to streams or the BMP. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Remove the weeds, preferably by hand. If a pesticide is used, wipe it on the plants rather than spraying. Unclog the pipe. Dispose of the sediment off-site. Replace the pipe. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Remove sediment and replace with clean stone. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 14 of 27

35 Stormwater Wetland Maintenance Requirements (Continued) Deep pool, shallow water and shallow land areas Embankment Algal growth covers over 50% of the deep pool and shallow water areas. Cattails, phragmites or other invasive plants cover 50% of the deep pool and shallow Shallow land remains flooded more than 5 days after a storm event. Plants are dead, diseased or dying. Consult a professional to remove and control the algal growth. Remove invasives by physical removal or by wiping them with pesticide (do not spray) consult a professional. Unclog the outlet device immediately. Determine the source of the problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if necessary. Best professional practices Prune according to best professional practices. show that pruning is needed to maintain optimal plant Sediment has accumulated Search for the source of the sediment and remedy the problem if and reduced the depth to 75% possible. Remove the sediment and dispose of it in a location where it of the original design depth of will not cause impacts to streams or the BMP. A tree has started to grow on Consult a dam safety specialist to remove the tree. the embankment. An annual inspection by appropriate professional shows that the embankment Evidence of muskrat or beaver activity is present. Make all needed repairs. Consult a professional to remove muskrats or beavers. Micropool Sediment has accumulated Search for the source of the sediment and remedy the problem if and reduced the depth to 75% possible. Remove the sediment and dispose of it in a location where it of the original design depth. will not cause impacts to streams or the BMP. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of damage have occurred at the outlet. Contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 15 of 27

36 Wet Detention Pond Maintenance Requirements The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one is provided. Important maintenance procedures: Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the - basin should be watered twice weekly if needed, until the plants become established (commonly six weeks). No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to - establish the plants on the vegetated shelf. Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention - basin. If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the - emergency drain should be minimized to the maximum extent practical. - Once a year, a dam safety expert should inspect the embankment. After the wet detention pond is established, it should be inspected once a month and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance should be kept in a known set location and must be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How I will remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the BMP Areas of bare soil and/or erosive gullies have formed. Regrade the soil if necessary to remove the gully, and then plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Vegetation is too short or too long. Maintain vegetation at a height of approximately six inches. The inlet device The pipe is clogged. Unclog the pipe. Dispose of the sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged. The forebay Erosion is occurring in the swale. Stone verge is clogged or covered in sediment (if applicable). Sediment has accumulated to a depth greater than the original design depth for sediment storage. Erosion has occurred. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Remove sediment and replace with clean stone. Search for the source of the sediment and remedy the problem if possible. Remove the sediment and dispose of it in a location where it will not cause impacts to streams or the BMP. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. The vegetated shelf Weeds are present. Best professional practices show that pruning is needed to maintain optimal plant health. Plants are dead, diseased or dying. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. Prune according to best professional practices Determine the source of the problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 16 of 27

37 Wet Detention Pond Maintenance Requirements (Continued) The main treatment area Sediment has accumulated to a depth greater than the original design sediment storage depth. Algal growth covers over 50% of the area. Search for the source of the sediment and remedy the problem if possible. Remove the sediment and dispose of it in a location where it will not cause impacts to streams or the BMP. Consult a professional to remove and control the algal growth. The embankment Cattails, phragmites or other invasive plants cover 50% of the basin surface. Shrubs have started to grow on the embankment. Evidence of muskrat or beaver activity is present. A tree has started to grow on the embankment. Remove the plants by wiping them with pesticide (do not spray). Remove shrubs immediately. Use traps to remove muskrats and consult a professional to remove beavers. Consult a dam safety specialist to remove the tree. An annual inspection by an Make all needed repairs. appropriate professional shows that the embankment needs repair. (if applicable) The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of Contact the Chatham Park Stormwater Program Manager. damage have occurred at the outlet. The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 17 of 27

38 Wet Detention Pond Design Summary Wet Pond Diagram WET POND ID FOREBAY MAIN POND Permanent Pool El. Permanent Pool El. Temporary Pool El: Temporary Pool El: Pretreatment other Clean Out Depth: 0 Clean Out Depth: 0 No than forebay? Sediment Removal El: Sediment Removal El: Has Veg. Filter? Yes Bottom Elevation: Bottom Elevation: ATTACH ADDITIONAL SHEETS IF NECESSARY Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 18 of 27

39 Important operation and maintenance procedures: Rooftop Runoff Management Maintenance Requirements - The plants will be watered during extended periods of dry weather. - Fertilize only once per year as long as the rooftop runoff system is not intended for nutrient removal. The rooftop runoff management system will be inspected once a quarter and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: The plants materials The flow diversion structure Gutters, drains and spouts Potential problem: Weeds are present. Vegetation is dead or diseased. The structure is clogged. The structure is damaged. Clogging has occurred. Damage has occurred. How to remediate the problem: Remove the weeds by hand. Try to determine the cause of the problem (may wish to consult an expert). Correct the problem and replace the plants. Unclog the conveyance and dispose of any sediment off-site. Make any necessary repairs or replace if damage is too large for repair. Remove leaves, debris, and other foreign matter and dispose of in a manner that will not impact streams or the BMP. Repair or replace the damaged conveyances. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 19 of 27

40 Rainwater Harvesting Maintenance Requirements Important operation and maintenance procedures: The roof area will be maintained to reduce the debris and sediment load to the system. Excess debris can clog - the system and lead to bypass of the design storm, and reduced reuse volume. To ensure proper operation as designed, a licensed Professional Engineer, Landscape Architect, or other - qualified professional will inspect the system annually. - The system components will be repaired or replaced whenever they fail to function properly. If the outlet is metered, use must be recorded at a minimum of monthly. These records shall be kept on site for - inspection by DWQ. The system will be inspected by the owner/operator annually. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remediate the problem: The entire system A component of the system is Make any necessary repairs or replace if damage is too large for damaged or leaking. repair. Water is flowing out of the Check system for clogging and damage. Repair as needed so the overflow pipe during a design design volume is stored properly without discharging during a design rainfall or smaller (usually a 1 storm. or 1.5 rainfall). Check that the pump is operating properly and that the water is actually being used at the volume designed. The captured roof area Excess debris or sediment is present on the rooftop. If it is still not operating properly, then consult an expert. Remove the debris or sediment as soon as possible. The gutter system Gutters are clogged, or water is backing up out of the gutter system. Rooftop runoff not making it into gutter system. Unclog and remove debris. May need to install gutter screens to prevent future clogging. Correct the positioning or installation of gutters. Replace if necessary to capture the roof runoff. The pump The overflow pipe Pump is not operating properly. Erosion is evident at the overflow discharge point. The overflow pipe is clogged. Check to see if the system is clogged and flush if necessary. If it is still not operating, then consult an expert. Stabilize immediately. Unclog or replace if it cannot be unclogged. The secondary water The cistern The outflow pipe is damaged. Not operating properly. Sediment accumulation of 5% or more of the design volume. Repair or replace the pipe. Consult an expert. Remove sediment. Algae growth is present inside the cistern. Do not allow sunlight to penetrate the cistern. Treat the water to remove/prevent algae. The screens and filters Mosquitoes in the cistern. Debris and/or sediment has accumulated. Screens and filters are clogged. Check screens for damage and repair/replace. Treat with mosquito dunks if necessary. Search for the source of the debris/sediment and remedy the problem if possible. Clean/clear debris/sediment from screen or filter. Replace if it cannot be cleaned. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 20 of 27

41 Proprietary System Maintenance Requirements How many devices are Contech StormFilters? 1 ATTACH MANUFACTURER'S MAINTENANCE MANUAL FOR ALL PROPRIETARY DEVICES Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 21 of 27

42 Disconnected Impervious Area Maintenance Requirements Important operation and maintenance procedures: The roof area will be maintained to reduce the debris and sediment load to the system. Excess debris can clog - the system and lead to bypass of the design storm, and reduced infiltration and pollutant removal. To ensure proper operation as designed, a licensed Professional Engineer, Landscape Architect, or other - qualified professional will inspect the system annually. - The system components will be repaired or replaced whenever they fail to function properly. The system will be visually inspected by the owner/operator annually. Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: The captured impervious area The gutter system (if applicable) Roadways & parking lots (if applicable) Potential problem: Excess debris or sediment is present on the rooftop or impervious surface. Gutters are clogged, or water is backing up out of the gutter system. Rooftop runoff not making it into gutter system. Rooftop runoff causing erosion at outlet. Runoff flows to the pervious area as concentrated flow. Energy dissipaters are unever settled, undercut, eroded or otherwise damaged. How to remediate the problem: Remove the debris or sediment as soon as possible. Unclog and remove debris. May need to install gutter screens to prevent future clogging. Correct the positioning or installation of gutters. Replace if necessary to capture the roof runoff. Install or repair splash blocks as needed. Remove any sediment or obstructuions at the edge of the impervious area, repair gravel verge Repair or replace energy dissipater. The pervious area Erosion is evident There is erosion around the end of the pervious area that shows stormwater has bypassed it. Unintended trees or shrubs have begun to grow in the pervious area. Areas of bare soil and/or erosive gullies have formed. Standing water is present 24 hours after rainfall. Vegetation is too long. Repair the eroded area and stabilize immediately. Regrade the soil to create a small berm, and then plant turf grass and water until it is established. Provide lime and a one-time fertilizer application. Remove them and re-establish vegetation per the original landscaping plan. Regrade the soil if necessary to remove the gully, and then plant with turf grass and water until it is established. Provide lime and a onetime fertilizer application. Fill shallow depressions with topsoul and seed mix. Regrade the area as necessary to reestablish sheet flow across the pervious area. Maintain vegetation at a height of approximately 2 to 6 inches. Property Owner Participation Homeowners have re-routed gutters or otherwise altered the system in a manner which adversely impacts performance. Provide educational materials to homeowners, and contact the Chatham Park Stormwater Program Manager. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 22 of 27

43 User Defined BMP Maintenance Requirements Section 1 Important operation and maintenance procedures: The system will be visually inspected by the owner/operator annually. Records of operation and maintenance will be kept in a known set location and will be available upon request. Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 23 of 27

44 Section 2 Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How to remediate the problem: Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 24 of 27

45 Stromwater Tree Well Maintenance Requirements Important operation and maintenance procedures: Immediately after the tree well is established, the plants will be watered twice weekly if needed until the plants become established (commonly six weeks). Wheeled or tracked equipment will NEVER be driven over the tree well planting surface. Special care will be taken to prevent sediment from entering the tree well. If standing water is present 2 days after rainfall, conduct an infiltration test of the soil media. After the tree well is established, visually inspect it monthly. Inspection activities shall be performed as follows and maintenance activites shall commence immediately to remediate any problems observed per the table below. BMP element: Potential problem: How to remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the BMP The pretreatment area Areas of bare soil and/or erosive gullies have formed. Broken or damagerd concrete or edge material Curb Cuts / Inlets The inlet is clogged. Unclog the inlet, remove sediment / debris / trash. Dispose of the sediment off-site. Erosion is occurring in the tree well. Sediment has accumulated to a depth greater than three inches. Erosion has occurred. Regrade the soil to remove the gully, plant new vegetation, and plant a ground cover and water until it is established. Provide lime and a onetime fertilizer application. Repair conrete or edge material to original design specifications. Regrade the splash pad and planting surface to smooth it over and provide erosion control devices such as additional / larger river rock, reinforced turf matting or riprap to avoid future problems. Search for the source of the sediment and remedy the problem if possible. Remove the sediment and restabilize the pretreatment area. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Weeds are present. Remove the weeds, preferably by hand. The tree well vegetation: Best professional practices show that pruning is needed to maintain optimal plant health. Plants are dead, diseased or dying. Tree stakes/wires are present six months after planting. Prune according to best professional practices. Determine the source of the problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. Remove tree stake/wires (which can kill the tree if not removed). Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 25 of 27

46 Stormwater Tree Well Maintenance Requirements (continued) BMP element: Potential problem: How to remediate the problem: The tree well soils and mulch: Mulch is breaking down or has floated away. Spot mulch if there are only random void areas. Replace whole mulch layer if necessary. Remove the remaining much and replace with triple shredded hard wood mulch at a maximum depth of three inches. Soils and/or mulch are clogged with sediment. Determine the extent of the clogging - remove and replace either just the top layers or the entire media as needed. Dispose of the spoil in an appropriate off-site location. Use triple shredded hard wood mulch at the depth indicated on the construction plans. Search for the source of the sediment and remedy the problem if possible. An annual soil test shows that ph has dropped or heavy metals have accumulated in the soil media. Dolomitic lime shall be applied as recommended per the soil test and toxic soils shall be removed, disposed of properly and replaced with new planting media. The underdrain system (if applicable) Clogging has occurred. Wash out the underdrain system. Pipe repair may be needed is underdrain pipe is crushed. The atrium grate Clogging has occurred. Cleanoff the grate. Dispose of debris off-site. The receiving water The atrium grate is damaged Repair or replace broken grates. Erosion or other signs of damage have occurred at the outlet. Contact the Chatham Park Stormwater Program Manager Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 26 of 27

47 Project Name: 0 Location: 0 Maintenance Log Below, list minor maintenance activities which were undertaken in response ot poor function of the BMP. Date BMP Maintenance Performed: Chatham Park BMP O&M Forms, Ver 1.0 6/27/2017 Page 27 of 27