Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.2

Inquiry

Option 1: Existing Imperviousness is Less Than 50% The stormwater management plan already in place was created with the existing Winkler Botanical Preserve Pond, which was designed and constructed to treat all runoff from, among other areas, Mark Center Plaza 1A & 1B, which includes the subject site. Based on a review of the design plans for this pond, the post-development peak discharges for the 1- and 2-year storms are reduced below pre-development levels. However, the pond is not designed to achieve this reduction over a 24 hour period, which is required to obtain this credit under this option. Another option for achieving this credit is to implement a stormwater management plan that protects receiving stream channels from excessive erosion by implementing a stream channel protection strategy and quantity control strategies. Obviously, short of credit acceptance, please confirm that the subject site meets this criteria for the following reasons, or whether key components are still missing: 1) As shown on the Winkler Botanical Preserve Pond Design Plans that will be provided with the full credit submission, the stormwater management facility that serves this site is designed to: a. Capture and treat 100% of runoff from this site. b. Reduce post-development peak discharge rates below pre-development levels. i. 2-yr pre-development peak discharge = 200 cfs ii. 2-yr post-development peak discharge = 197 cfs iii. 10-yr pre-development peak discharge = 436 cfs iv. 10-yr post-development peak discharge = 396 cfs 2) As shown on the Mark Center Plaza 1A & 1B Preliminary Development Plan and the Winkler Botanical Preserve Pond Plan, the following measures were designed and installed to reduce runoff velocities and prevent erosion in the receiving channels leading to the Winkler Botanical Preserve Pond: a. Rip-rap plunge pools were installed at all pipe outfalls in order to dissipate velocities exiting pipes and entering open channels. See Winkler Botanical Preserve Pond Plan. b. Slope reinforcement was placed downstream of plunge pools for pipe outfalls to further protect stream channels from runoff exiting pipe outfalls and entering stream channels. c. Linear Lakes were installed in the main stream channel which feeds into Winkler Botanical Preserve Pond and conveys most of the runoff from the subject site. Linear Lakes are a series of three weir structures which reduce the velocity of runoff in the open channel and prevent erosion as the stream channel flows into the Winkler Botanical Preserve Pond.