7301 HARDESON RD 2019-01-11 - Laserfiche WebLink

PUBLIC WORKS o Clarify what type of treatment will be provided by the proposed Oldcastle PerkFilters (e.g., basic, enhanced, phosphorus, oil control). c. Section 1.2—Governing Guidelines o Figure 2.4.1 was used to determine MR applicability for the project. This figure is to be used for new development, which include sites with less than 35% existing impervious coverage. o Calculate the percentage of the site with existing impervious coverage, using the definition of impervious surface provided in the Glossary of Volume I of the SWMM, as follows: "...A non-vegetated surface area which either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development. A non-vegetated surface area which causes water to runoff the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include, but are not limited to, roof tops, walkways,patios, driveways,parking lots or storage areas, concrete or asphalt paving, gravel roads,packed earthen materials, and oiled, macadam or other surfaces which similarly impede the natural infiltration of stormwater. Open, uncovered retention/detention facilities shall not be considered as impervious surfaces for the purposes of determining whether the thresholds for application of minimum requirements are exceeded. Open, uncovered retention/detention facilities shall be considered impervious surfaces for purposes of runoff modeling. " o Document the rationale for using Figure 2.4.1 or Figure 2.4.2 to determine MR applicability based on the above. o Document which MRs apply to which surfaces (i.e.,new and/or replaced hard surfaces, converted vegetation areas, land disturbed), organized by TDA. d. Section 2.2—Soils o Update this section to document the requirements per Section 3.1.1,Vol. I of the SWMM e. Section 2.4 Critical and Adjacent Areas o Note that Merrill and Ring Creek is located on the west side of Hardeson Rd. opposite the site. f. Section 6.0—Special Reports and Studies o Page 5 of the Infiltration Evaluation prepared by GeoEngineers (2015), provided as an appendix in the SSP, was based on the assumption that the project would be designed to the City's 2010 Stormwater Management Manual. However, the evaluation must be performed and documented in Page 4 of 9.