PC-2021-18 - Laserfiche WebLink

that no storm runoff will flow across the subdivision boundary. (PROJECT SPECIFIC CONDITION) 47. MUNICIPAL REGIONAL PERMIT (C.3): Referring to the Vesting Tentative Map together with the Bay Area Hydraulic Model (BAHM) report, the following design parameters shall be checked by the applicant (Address this condition prior to improvement plan approval): a. The note at the bottom of the table on Sheet TM 5.0 states, "The calculations are based on the Alameda Countywide Clean Water Program C.3 Technical Guidance...", yet a report was submitted using BAHM. The note should therefore read, "The calculations are based on the Bay Area Hydraulic Model (BAHM). When comparing the numbers in the table to the BAHM calculation, the following discrepancies were noted: i. The input parameters in the BAHM calculations for DMA 2 (page 5) indicate an impervious total of 6.238 acres whereas the summation of areas from the table suggest a total of 6.45 acres (81,700 SF + 104,400 SF + 95,000 SF = 281,100 SF = 6.45 acres). ii. Based on the impervious area total, the BAHM calculations (page 12) indicate a needed area for DMA 2 of 25,000 SF (200' X 125' = 25,000 SF). In contrast, the table shows a provided area of 24,850 SF. b. Because the storm drain design proposes the use of two parallel pipe networks, one for storm runoff requiring treatment, and one for storm runoff from open space areas that does not require treatment that converge at BMP 2, BMP 2 will function both as a treatment feature and detention basin during large storm events. The BAHM calculations (page 12) indicate that water will rise to a depth of 2.5' or 30" before discharging into the overflow outlet. The landscaping within the basin must therefore be designed to survive when inundated. In addition, water in the basin that rises above 18" is considered a drowning risk for children. The California Building Code requires said basins to be enclosed with a self-closing, self-latching fence with release mechanisms placed at least 54 inches from the ground surface. The fence must be at least 60"-high and have a maximum vertical clearance of 2" from the ground to the bottom of the fence. There must be no gaps, voids or other features that may allow a child under 5 years old to climb over. (PROJECT SPECIFIC CONDITION) 48. EXISTING WINDMILL: A windmill well pump exists within the eastern portion of Parcel A. If the well will no longer be used, it shall be abandoned according to Alameda County General Ordinance No. 0-2015-20 as administered by Zone 7 Water Agency. If instead it will be utilized for irrigation water, the applicant shall assure that the well pump is sufficient to service the flow and pressure demands PUD-138 and VTM 8616 Planning Commission Page 13 of 30 g permit issuance. Such fees include, but are not limited to, the pro-rata share of PUD-138 and VTM 8616 Planning Commission Page 10 of 30 nt. No objections or comments have been received at the time this report was prepared. ect property is not located in a flood hazard zone. As such, the Commission recommends that the City Council conclude that this finding can be made. censed civil engineer, which include but is not limited to the type, location, and sizing calculations of the PUD-114-01M& P20-0995 Planning Commission Page 16 of 25 d) individuals. PUD-114-01M& P20-0995 Planning Commission Page 3 of 25