2026 02 12 Crestmont CC and Eagle Rock Ave Stormwater Management Report

Table 14 – Porous Asphalt Pavement System Design Summary Ratio of Groundwater Bottom of Highest BMP Additional Test Pits2 or Mottling BMP EL.3 Bedrock EL.4 Inflow Area1 EL. PAPS-1 1.89 TP-9, TP-13, TP-14 553.00 548.05 557.256 Notes: 1. The ratio of additional inflow area is the contributing watershed area to a porous pavement system in relationship to the surface area of the porous pavement. 2. Refer to the drainage plans, drawings CG103 & CG104, for BMP locations. Refer to Appendix F for supporting geotechnical investigation information including test pit logs. 3. The bottom of BMP elevation is the bottom of the stone storage layer for a porous asphalt pavement system. 4. If groundwater and soil mottling were not encountered, the limiting design feature is bedrock. In this case, rock will be excavated to be a minimum of one foot below the bottom BMP elevation. 5. Within PAPS-1, the following test pits were performed and indicated the following elevations of groundwater or mottling: TP-9 did not encounter groundwater, TP-14 did not encounter groundwater, and TP-13 encountered groundwater at el. 548.0. 6. Within PAPS-1, the following test pits were performed and indicated the following elevations of bedrock: TP-9 encountered bedrock at el. 545.0, TP-13 encountered bedrock at el. 542.5, and TP-14 encountered bedrock at el. 557.25. Refer to Figure 10 – Test Pit Location Plan, for a map showing the locations of the test pits with respect to the proposed BMP footprints. 3.1.9 Stormwater Quantity Summary A summary for each point of analysis, detailing the existing, allowable, and proposed peak discharge rates, is outlined in the table below. Table 15 – POA-1 Peak Discharge Summary – Current Storm Events POA-1 Design Storm

ined in the table below. Table 15 – POA-1 Peak Discharge Summary – Current Storm Events POA-1 Design Storm Event Existing Peak Allowable Peak Proposed Peak Discharge (CFS) Discharge (CFS) Discharge (CFS) 2-Year 13.48 12.57 11.32 10-Year 23.47 22.52 19.76 100-Year 44.56 42.92 38.87 15