1240815MAINTENANCE MANUAL rcd 3 12 2026

Basic Design Information This section shall be filled out by the design engineer. Hydrology Design Targets 1. The system is porous pavers with storage bed. 2. This system is designed with a soil permeability rate of 5.8 inches/hour (pre- construction) and 2.9 inches/hour (post-construction). 3. The design drain time is 24.10 hours. 4. The elevation of the seasonal high water table of this pavers area was observed on 06-30-2025 and it was more than 7 feet below the pavers bottom surface, at EL. 413.50 feet. 5. The TSS removal rate is 80%. Hydraulic Design Targets 1. This system is designed to infiltrate the runoff from the (Water Quality Design Storm / groundwater recharge storm), which generates 0.168 acre feet of runoff. The peak flow entering the system is 0.45 cubic feet per second. 2. The invert elevation of the overflow outlet is at EL. 414.50 feet. System Configuration Targets 1. The system has no pretreatment. 2. The depth of uniformly graded coarse aggregate in the storage bed is 32 inches. 3. The top of the system is for permeable pavers only. Critical Maintenance Features 1. Avoid sand or silt onto the porous pavers area. 2. Sweep and vacuum the porous pavers area often to prevent clog. 3. Do not apply sealant to cracks or entire surface. 20

PART VI – Underground Pipe System BMP#2 Functionality The underground detention system is a subsurface storage facility that receives and temporarily stores stormwater runoff from roofs of structures, parking lots, and grass areas. Discharge of the stored runoff from the underground system occurs through gravity by a discharge structure. An underground system may be either a structural chamber and/or an excavated pit filled with aggregate. The system may also be a set of pipes surrounded in stone or a set of pipes without stone. Due to its storage capacity, an underground system may be used to reduce the total stormwater quantity design storm runoff volume that a site would ordinarily discharge to downstream stormwater management facilities. Underground systems can be used to reduce the increased volume of stormwater runoff caused by a whole site. Underground systems can also be used to indirectly enhance water quality by reducing the amount of stormwater quality design storm runoff volume to be treated by the other, downstream stormwater management facilities. Underground systems can also be used to meet the groundwater recharge requirements of the NJDEP Stormwater Management Rules. Proper care and attention in the long-term maintenance of the stormwater management measure is critically important to the safety and health of the public. Type of BMP – Dry Stormwater Management Measure An underground system is a type of dry stormwater management measure. Dry stormwater management measures must fully drain within 72 hours of the most recent rainfall. Standing water in excess of 72 hours is a sign of failure. It may also contribute to mosquito breeding and other health and safety issues. The design drain time shall be closely monitored to ensure that potential failure is recognized early. Underground systems can detain, infiltrate, and recharge stormwater runoff; however, underground systems are not designed to treat stormwater runoff for water quality; therefore, no TSS removal is assigned to the system. Basic Design Information Hydrology Design Targets -This underground system is designed with a subsoil permeability rate of 5.8 inches/hour (pre-construction) and 2.9 inches/hour (post-construction). -The design drain time is 24.30 hours. -The elevation of the seasonal high water table of this system was observed to

pre-construction) and 2.9 inches/hour (post-construction). -The design drain time is 24.30 hours. -The elevation of the seasonal high water table of this system was observed to be 7 feet below the systems bottom surface, at EL.410.50 feet. Hydraulic Design Targets -This underground system is designed to infiltrate the runoff from the (Water Quality Design Storm / groundwater recharge storm), which generates 0.005 acre feet of runoff. 21

Underground System Configuration Targets -The dimensions of the system are 10’ x 40’ x 3’ deep. -The perforated pipes are 24 inches in diameter. The perforations are 3/8” inches in diameter and are arranged 6 inches center to center, 6 perforations per row, and 48 rows of perforations per 20’ pipe. -The stone fill uses crushed stone ¾ inches in diameter. Critical Maintenance Features -Check downspout and bypass frequently and remove leaves and other debris immediately. -Check inspection port for excessive sediment. 22

PART VII - Inspection Checklist / Maintenance Actions Checklist (circle one): Quarterly / Annual / Monthly / Special Event Inspection Checklist No. ______________ Inspection Date: _______________ Preventative Maintenance Date of most recent rain event: __________ Frequency Circle One Quarterly Annual Rain Event Rain Condition (circle one): Drizzle / Shower / Downpour / Other _____________ Ground Condition (circle one): Dry / Moist / Ponding / Submerged / Snow accumulation For Inspector For Maintenance Crew Component No. Preventative / Corrective Inspection Item and Component Inspected Maintenance Actions Inspection Item No. Name Comments Y__ . 1 Standing water observed. N__ Excessive sediment, mud or Y__ 2 debris accumulation on top N__ of the pavement Cracking, subsidence, Y__ 3 spalling, or other damage to N__ the pavement Porous Pavers BMP#1 Weeds or other vegetation Y__ 4 on the porous pavement N__ Y__ 5 N__ ________________________ __________________ ________________ Inspector Name Signature Date 23

For Inspector For Maintenance Crew Component No. Preventative / Corrective Inspection Item and Component Inspected Maintenance Actions Inspection Item No. Name Comments Man holes broken or in Y__ 1 disrepair N__ Pipes have standing water Y__ after the design drain time . 2 N__ Sediment and standing water observed. Excessive sediment or Y__ 3 debris present in the N__ inspection port Y__ Underground Little or no flow into the 4 N__ Pipe System system BMP#2 Downspout or Overflow pipe Y__ 5 is clogged N__ Y__ 6 Odor present N__ Y__ Overflow from the top of the 7 N__ discharge structure Y__ 8 Storm Collection System N__ Y__ 9 N__ Note: ________________________ __________________ ________________ Inspector Name Signature Date 24