801 E CASINO RD 2019-02-01 - Laserfiche WebLink

incorporated into the erosion control design. The full erosion and sediment control design is described in more detail in Section 4.0 of this report and in the project plans. 3.2.3 M.R.#3—Source Control of Pollution The proposed project consists of field improvements to an existing school site, and subsequently, is not subject to water quality source control requirements as defined in the Stormwater Management Manual for commercial developments. Upon review of Volume IV of the manual, there are no known activities that are potential sources of pollutants. 3.2.4 M.R.#4—Preservation of Natural Drainage Systems and Outfalls As previously mentioned, the existing drainage system will primarily remain in place. Currently, stormwater runoff from the project area flows east through a series of catch basins and pipes to an 18"diameter storm system adjacent to the existing tennis courts. From here, the onsite conveyance system directs runoff north to a 27" storm drain in Bruin Boulevard (See Appendix B - Existing Drainage Map). Upon project completion, stormwater runoff will continue to flow to the site's existing discharge location in Bruin Boulevard. No diversion of stormwater runoff is proposed. 3.2.5 M.R.#5—Onsite Stormwater Management Stormwater management Best Management Practices(BMP's)have been implemented to infiltrate, retain, and disperse stormwater runoff to minimize flooding or erosion downstream. 3.2.6 M.R.#7—Flow Control The football field improvements includes excavation of 8 inches of existing grass and sand base in order to install the new synthetic turf; shock pad, and 6 inches of washed crushed rock. Under the current plan, approximately 1 inch depth of the existing sand base and perforated underdrain system will remain in place. As such, the proposed improvements should not affect the existing hydrology of the field and its ability to infiltrate stormwater, as in the existing conditions. Based on this qualitative assessment, no increase in stormwater runoff is anticipated to downstream drainage systems. Similarly, the new asphalt pedestrian path on the east side of the field will be constructed to disperse stormwater runoff onsite. To address the flow control requirements for this impervious area, Section 2.2.7 on page 2-13 states the following: "Application of Low Impact Development techniques and Onsite Stormwater management BMP's can result in reducing the effective impervious area, thereby reducing or eliminating the need for flow control and treatment facilities. Impervious surfaces that are fully dispersed in accordance with Volume III, Chapter 12 are not considered effective impervious surfaces. " As such, BMP 12.70 will be incorporated into the design of the asphalt path, per Section 12.3.7, since sheet flow dispersion is the simplest method of runoff control. This BMP will be used to sheetflow and disperse runoff from the asphalt path into an Technical Information Report Synthetic Turf Field Project 3 Integrityworks Consulting Engineers,LLC Project No.212107