2219 PINEHURST AVE BASE FILE 2020-07-14

On-Site Stormwater BMPs The project is subject to the provisions of the 2014 DOE Stormwater Management Manual. This report, along with the accompanying plans, is intended to satisfy the drainage manual's site plan preparation requirements. The DOE Manual outlines a number of minimum requirements which must be addressed as part of the design. The minimum requirements for"new development" projects are determined from Volume I, Figure 1.1 of the DOE manual, as follows: DOE requires the implementation of on-site stormwater Best Management Practices (BMPs), (often referred to as"low-impact" BMP's)wherever feasible. The goal of these BMPs is to decentralize stormwater detention and treatment throughout the site, and more actively manage stormwater runoff from very small, but frequent storm events. Volume I, Table 1.1 of the DOE Drainage Manual specifies the following on-site stormwater management requirements: Projects qualifying as flow control exempt in accordance with Section 2.5.7 of this chapter do not have to achieve the LID performance standard,nor consider bioretention,rain gardens,permeable pavement,and full dispersion if using List#1 or List#2,However,. those projects must implement BMP T5.13;BMPs T5.1OA,B,or C; and BMP T5.11or T5.12,if feasible. Project Thresholds Projects triggering only Minimum Requirements#1 through#5 shall either: a. Use On-site Stormwater Management BMPs from List#1 for all surfaces within each type of surface in List#1;or b. Demonstrate compliance with the LID Performance Standard. Projects selecting this option cannot use Rain Gardens.They may choose to use Biaretention BMPs as described in Chapter 7 of Volume V to achieve the LID Performance Standard. This project is exempt from Minimum Requirement 7 as set forth in Section 2.5.7 of this chapter do not have to achieve the LID performance standard, nor consider bioretention, rain gardens, permeable pavement, and full dispersion if using List#1 or List#2. However, those projects must implement the following BMPs if feasible: • BMP T5.13 Post-Construction Soil Quality and Depth; and • BMP T5.10A Downspout Full Infiltration Systems, BMP T5.10B Downspout Dispersion • Systems, or BMP T5.10C Perforated Stub-out Connections; and • BMP T5.11 Concentrated Flow Dispersion or BMP T5.12 Sheet Flow Dispersion. Since the project has an unsuitable soil type for infiltration, any infiltration is infeasible. Since there are no available flow path lengths for dispersion, dispersion is infeasible. We could install perforated stub out connections, but with the proposed connection into the sanitary sewer, this seems impractical as well. Thus,the project proposed to connect into the combined sanitary sewer/Stormwater system. Pinehurst Ave. Duplex Drainage Report