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Home My WebLink AboutSW3170504 (6)SUPPLEMENT -EZ FORM COVER PAGE Please indicate the types, quantities and locations of SCMs that will be used on this protect Quantity Location(s) Infiltration System _ Bioretention Cell Wet Pond - -- ----- - - -- - - - -- Stormwater Wetland Permeable Pavement Sand Filter 1 SW corner of site --------------------- ---- ------------ -- ----- ---------- Rainwater Harvesting _ Green Roof Level Spreader -Filter Strip ------_ T T Disconnected Impervious Surface Treatment Swale Dry Pond 1 SW corner of site — Designer information for this project: Name and Title Wesley Sherrill, Sr Project Manager/Civil Engineer Benesch 2320 W Morehead St Organization Street address City, State, Zip Charlotte, NC 28208 704-521-9880 Phone number(s) Email lwsherrill@benesch com Desig►ner Applicant: Project Name: Iredell Public Safety Center Address 404 Bristol Drive City / Town Statesville (n v0 onnm, Company Ire County Contact. -dell Ronald Rufus_S_m_ it_h- C_o_unty_Manager _ PO Box 788 Mailing Address City, State, Zip Statesville, NC 28_6_8_7 _ 704-878-3050 Phone number(s) Email rsmith@co iredell nc us een�ae11r®�q Certification Statement eee A U^1i° I certify, under penalty of law that this Supplement -EZ form and all supporting information were prepared under my direction or supervision, 0 t? that the information provided in the form is, to the best of my knowledge vwo'-z 71 and belief, true, accurate, and complete, and SEAL 7� Signature of esigner 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 ° °O°I'll,l E. S� ,t `e information including the possibility of fines and imprisonment for knowing O J'ARSeE&W10 I Date r Iviolations as well as a report being made to my professional board Cover Page 1 3:34 PM 5/10/2017 SAND FILTER Iredell Public Safety Center THE DRAINAGE AREA Drainage area number P -1A_ Break down of BUA in the drainage area (both new and existing): Total coastal wetlands area (sq ft) 0 Parking / driveway (sq ft) 87852 sf, Total surface water area (sq ft) �0 Sidewalk (sq ft) 8474 sf Total drainage area (sq ft) 406,350 sf Roof (sq ft) 37340 sf BUA associated with existing development (sq ft) 1 0 • Roadway (sq ft) 0 sf Proposed new BUA (sq ft) 133,666 ssf Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM 3311. Total BUA (sq ft) 133666 sf Stormwater program(s) that apply (please specify) Design rainfall depth (in) 1 0 in Minimum volume required (cu ft) 11689 cf Design volume of SCM (cu ft) 11689 cf GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build -out? Yes' #7 If applicable, with the SCM be cleaned out after construction? Yes #2 Is the SCM located on or near contaminated sods? No #8 Does the mametenance access comply with General MDC (8)? Yes #3 What are the side slopes of the SCM (H V)? 31 #9 Does the drainage easement comply with General MDC (9)? Yes #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes'? No #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? Yes #4 Are the inlets, outlets, and receiving stream protected from erosion (10 -year storm)? Yes #11 Is there an O&M Agreement that complies with General MDC (11)? Yes #5 Is there a a bypass for flows in excess of the design flow? Yes #12 Is there an O&M Plan that complies with General MDC (112)? Yes #6 What is the method for dewatenng the SCM for maintenance? Drawdown Onfice #13 Was the SCM designed by an NC licensed professional? Yes SAND FILTER MDC FROM 02H.1056 #1 SHWT elevation (fmsl) < 931 0 #3 Volume of stormwater from drainage area during design storm (cubic feet) 71308 cf #1 Type of sand filter (open or closed) Open #3 Total volume that can be stored above the sediment and sand chambers (cubic feet) 54303 cf #1 If closed, describe if the filter will be pre -cast or pour -m -place #3 Is this sand filter designed to attenuate peak flows? Yes ' #3 Elevation of the bypass device (fmsl) 93335 _ #1 if closed, top of grate elevation (fmsl) #3 Describe the bypass device #2 Volume that can be retained in the sediment chamber (cubic feet) Vertical 6" wide slot in outlet control structure #2 Will there be a permanent pool in the sediment chamber? #2 Bottom of the sediment chamber (fmsl) #4 Ponding depth from the top of the sand to the bypass device (ft) 135 #2 Area of the sediment chamber (square feet) #5 Describe the mechanism for distributing flow over the sand surface #2 Physical depth of the sediment chamber (inches) ponding within basin #2 Ponding depth in the sediment chamber, above any permanent pool (inches) #6 Sand specification for sand chamber #2 Elevation of top of weir between chambers (fmsl) Coarse masonry sand complying with ASTM C33 #2 Volume that can be retained in the sand chamber (cubic feet) 92 Bottom of the sand chamber (fmsl) #7 Depth above underdrain pipe (inches) 12 in #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? Yes #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? Yes #2 Ponding depth in the sand chamber, above any permanent pool (inches) #9 Will clean-out pipes be capped? Yes ADDITIONAL INFORMATION Please use this space to provide any additional information about this sand filter that you think is relevant to the review Sand Filter 2 3.34 PM 5/10/2017 DRY POND Iredell Public Safety Center THE DRAINAGE AREA Drainage area number P -1A Break down of BUA in the drainage area (both new and existing): Total coastal wetlands area (sq ft) 0 sf Parking / driveway (sq ft) 87852 sf Total surface water area (sq ft) 0 sf Sidewalk (sq ft) 8474 sf Total drainage area (sq ft) 406,350 Roof (sq ft) 37340 sf BUA associated with existing development (sq ft) 0 sf Roadway (sq ft) 0 sf Proposed new BUA (sq ft) 133,666 Other, please specify in the comment box below (sq ft) Percent BUA of drainage area COMPLIANCE WITH THE APPLICABLE STORMWATER PROGRAM 33% ITotal BUA (sq ft) 133666 sf Stormwater program(s) that apply (please specify) Design rainfall depth (in) 4 9 in Minimum volume required (cu ft) 33635 cf Design volume of SCM (cu ft) 54303 cf GENERAL MDC FROM 02H.1050 #1 Is the SCM sized to treat the SW from all surfaces at build -out? Yes #7 If applicable, with the SCM be cleaned out after construction Yes #2 Is the SCM located on or near contaminated soils? No #8 Does the mainetenance access comply with General MDC (8)? #3 What are the side slopes of the SCM (H V)? 31 #9 Does the drainage easement comply—with General MDC (9)) _Yes Yes #3 Does the SCM have retaining walls, gabion walls or other engineered side slopes? No #10 If the SCM is on a single family lot, does the plat comply with General MDC (10)? Yes #4 Are the inlets, outlets, and receiving stream protected from erosion (10 -year storm)? _ Yes #11 Is there an O&M Agreement that complies with General MDC (11)? Yes #5 Is there a a bypass for flows in excess of the design flow? Yes #12 Is there an O&M Plan that complies with General MDC (12)? Yes, #6 What is the method for dewatering the SCM for maintenance? Drawdown Onfice #13 Was the SCM designed by an NC licensed professional? Yes DRY POND MDC FROM 02H .1062 #1 SHWT elevation (fmsl) <931 0 #5 Describe the pretreatment that will be provided for the dry pond #1 Elevation of the bottom of the dry pond (fmsl) 932 ft Forebay #1 Distance from bottom to SHWT (feet) >1 #6 Size of drawdown onfice (in) 6 0 in #2 Elevation of the temporary pool during the design storm (feet) 93483 #6 Drawdown time for the temporary pool (hours) 51 hrs #2 Ponding depth of the design storm (feet) 2 83 ft� #7 Does the pond minimize impacts to the receiving channel from the 1 -yr, 24 -hr storm? Yes #3 Will the dry pond be uniformly graded to flow toward the outlet? Yes #8 Is there a small permantent pool near the onfice to prevent clogging? No #3 Is a low flow channel being provwded9 No #8 Descnbe how the outlet will be designed to prevent clogging #4 Are the mlet(s) and outlet located in a manner that avoids short-circuiting? Yes #4 Describe any measures, such as berms or baffles, that will be taken to increase the flow path Forebay berm #9 Are the dam and embankment planted in non -dumping turf grass? Yes #9 Species of turf that will be used on the dam and embankment Sod #9 Will trees and shrubs be prevented from grovnng on the dam and embankment? No ADDITIONAL INFORMATION Please use this space to provide any additional information about this dry pond that you think is relevant to the review Dry Pond 4 3 34 PM 5/10/2017 Operation & Maintenance-A,greement = Project Name: I Iredell County Public Safety Center Project Location: I Statesville, NC Maintenance records shall be kept on the following BMP(s). This maintenance record shall be kept in a log in a known set location. 'Any deficient BMP elements noted in the inspection will be corrected, repaired, or replaced immediately. These deficiencies can affect the integrity of structures, safety of the public, and the pollutant removal efficiency of the BMP(s) The BMP(s) on this project include (check all that apply & ci Bioretention Cell Quantity* Dry Detention Basin Quantity Grassed Swale Quantity Green Roof Quantity: Infiltration Basin Quantity: Infiltration Trench Quantity: Level SpreaderNFS Quantity Permeable Pavement Quantity Proprietary System Quantity, Rainwater Harvesting Quantity Sand Filter Quantity, Stormwater Wetland Quantity Wet Detention Basin Quantity Disconnected Impervious Area Present User Defined BMP Present. ng O&M tables wil Location(s) Location(s) Location(s). Location(s) Location(s) Location(s). Location(s)* Location(s), Location(s): Location(s). Location(s): Location(s) Location(s) Location(s), Location(s). be added automatical I SW corner of site I I SW corner of site I I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for each BMP above, and attached O&M tables. I agree to notify NCDENR of any problems with the system or prior to any changes to the system or responsible party * Responsible Party. Title & Organization. Street address, City, state, zip, Phone number(s) Email Ronald Rufus Smith County Manager, Iredell County NC 200 South Center Street Statesville NC 28687 704 8783050 rsmith@co.iredell.nc.us r Signatur (MK Date: a/ 7�/eF'' a Notary Public for the State of n o -HX Gro �I County of �rec�,el� do hearby certify that IonakJAuAsSm;9, re No-naQer personally appeared before me this 41 day of Aa V and acknowledge the due execution of the and,Maintenance Agreement Witness my hand and official seal, C/r� 0VU My commission expires STORM -EZ 5/2/2017 Version 1 4 O&M Manual Page 1 of 5 Dry Detention Pond Maintenance Requirements _ Y 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 quarterly. 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 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 Replace the pipe otherwise damaged. Erosion is occurring in the Regrade the swale if necessary to smooth it over and provide erosion swale control devices such as reinforced turf matting or nprap to avoid future problems with erosion 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 Provide additional erosion protection such as reinforced turf matting or nprap is displaced nprap if needed to prevent future erosion problems. Weeds are present. Remove the weeds, preferably by hand If pesticides are used, wipe them on the plants rather than spraying STORM -EZ 5/2/2017 Version 1 4 O&M Manual Page 2 of 5 -Dry Detention Pond Maintenance Requirements (continued) l BMP element: Potential problem: How to remediate the problem: The main treatment area Sediment has accumulated Search for the source of the sediment and remedy the problem if and reduced the depth to possible. Remove the sediment and dispose of it in a location where 75% of the original design it will not cause impacts to streams or the BMP Revegetate disturbed depth (per pond design data areas immediately with sod (preferred) or seed protected with securely sheet) staked erosion mat. Water is standing more than Check outlet structure for clogging If it is a design issue, consult an 5 days after a storm event. appropriate professional Weeds and noxious plants Remove the plants by hand or by wiping them with pesticide (do not are growing in the main spray) treatment area. The embankment Shrubs or trees have started Remove shrubs or trees immediately to grow on the embankment Grass cover is unhealthy or Restore the health of the grass cover — consult a professional if eroding necessary. Signs of seepage on the Consult a professional downstream face Evidence of muskrat or Use traps to remove muskrats and consult a professional to remove beaver activity is present beavers An annual inspection by an Make all needed repairs appropriate professional shows that the embankment needs repair. 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 local NC Department of Environment and Natural damage have occurred at the Resources Regional Office outlet STORM -EZ 5/2/2017 Version 1 4 O&M Manual Page 3 of 5 Dry Detention Pond Design Summary DrV Pond Diagram DRY POND ID FOREBAY MAIN POND Temporary Pool EI E934 83 Temporary Pool EI M93483Clean Out Depth 73 Clean Out Depth Pretreatment Yes Sediment Storage EI: 3 1 Sediment Storage EI Has Veg Filter No Bottom Elevation 33 Bottom Elevation: STORM -EZ 5/9/2017 Version 1 4 O&M Manual Page 5 of 6 { Sand Filter Maintenance Requirements j 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 - 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 quarterly 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 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 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 one- time fertilizer application. Vegetation is too short or too Maintain vegetation at an appropriate height long 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 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 Regrade the swale if necessary to smooth it over and provide erosion swale control devices such as reinforced turf matting or nprap to avoid future problems with erosion Stone verge is clogged or Remove sediment and replace with clean stone covered in sediment (if applicable) Forebay or pretreatment Sediment has accumulated to Search for the source of the sediment and remedy the problem if area a depth of greater than six possible. Remove the sediment and stabilize or dispose of it in a inches. location where it will not cause impacts to streams or the BMP Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or nprap if needed to prevent future erosion problems Weeds are present Remove the weeds, preferably by hand. If a pesticide is used, wipe it on the plants rather than spraying. Filter bed and underdrain Water is ponding on the Check to see if the collector system is clogged and flush if necessary collection system surface for more than 24 If water still ponds, remove the top few inches of filter bed media and hours after a storm. 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 Contact the local NC Department of Environment and Natural damage have occurred at the Resources Regional Office outlet STORM -EZ 5/2/2017 Version 1 4 O&M Manual Page 5 of 5