28-14 Amend Chp. 1339 Storm Water Mgmt

Home Browse Search

* Dry bashrs must include forebay and micropool each sized at 10 percent of the WQv ** Provide both a permanent pool and an EDv above the permanent pool, each sized at 0.75 WQv. + Extended detention shall be provided for the full WQv above the permanent water pool. A The WQv shall completely infiltrate within 48 hours so there is no standing or residual water in the BMP. # Pocket wetlands must have a wet pool equal to the WQv, with 25 percent of the WQv in a pool and 75 percent in marshes. The EDv above the permanent pool must be equal to the WQv. (7) The owner may request approval fi-om the City Engineer to use alternative structural post-construction BMPs if the owner can demon- strate, in a way that is acceptable to Ohio EPA rules and regulations, that the alternative BMPs are equivalent in effectiveness to those listed in Table 2 above. The use of alternative or vender supplied post - construction BMPs should be limited to redevelopment projects where justification is provided that the traditional BMPs in Table 2 are techni- cally and economically infeasible. (8) Construction activities shall be exempt from this condition if it can be demonstrated that the WQv is provided within an existing structural post - construction BMP that is part of a larger common plan of devel- opment or sale or if structural post - construction BMPs are addressed in a regional or local storm water management plan. A municipally oper- ated regional storm water BMP can be used as a post - construction BMP provided that the BMP can detain the WQv from the entire drainage ar- ea and release it over a 24 -hour period upon written permission from the city engineer. (9) For redevelopment projects (i.e., developments on previously devel- oped property), post - construction practices shall either ensure a 20 per- cent net reduction of the site impervious area, provide for treatment of at least 20 percent of the WQv, or a combination of the two. Where projects are a combination of new development and redevelopment, the total WQv that must be treated shall be calculated by a weighted aver- age based or acreage, with the new development at 100 percent WQv and redevelopment at 20 percent WQv. (10) Site Description: A. The prior land uses of the site; B. The nature and type of construction activity (e.g., low density resi- dential, shopping mall or highway); 60 ment Infiltration Permeable Pave- 24 Hours rnent Ext. Deten- tion * Dry bashrs must include forebay and micropool each sized at 10 percent of the WQv ** Provide both a permanent pool and an EDv above the permanent pool, each sized at 0.75 WQv. + Extended detention shall be provided for the full WQv above the permanent water pool. A The WQv shall completely infiltrate within 48 hours so there is no standing or residual water in the BMP. # Pocket wetlands must have a wet pool equal to the WQv, with 25 percent of the WQv in a pool and 75 percent in marshes. The EDv above the permanent pool must be equal to the WQv. (7) The owner may request approval fi-om the City Engineer to use alternative structural post-construction BMPs if the owner can demon- strate, in a way that is acceptable to Ohio EPA rules and regulations, that the alternative BMPs are equivalent in effectiveness to those listed in Table 2 above. The use of alternative or vender supplied post - construction BMPs should be limited to redevelopment projects where justification is provided that the traditional BMPs in Table 2 are techni- cally and economically infeasible. (8) Construction activities shall be exempt from this condition if it can be demonstrated that the WQv is provided within an existing structural post - construction BMP that is part of a larger common plan of devel- opment or sale or if structural post - construction BMPs are addressed in a regional or local storm water management plan. A municipally oper- ated regional storm water BMP can be used as a post - construction BMP provided that the BMP can detain the WQv from the entire drainage ar- ea and release it over a 24 -hour period upon written permission from the city engineer. (9) For redevelopment projects (i.e., developments on previously devel- oped property), post - construction practices shall either ensure a 20 per- cent net reduction of the site impervious area, provide for treatment of at least 20 percent of the WQv, or a combination of the two. Where projects are a combination of new development and redevelopment, the total WQv that must be treated shall be calculated by a weighted aver- age based or acreage, with the new development at 100 percent WQv and redevelopment at 20 percent WQv. (10) Site Description: A. The prior land uses of the site; B. The nature and type of construction activity (e.g., low density resi- dential, shopping mall or highway); 60