Question 2 Show Answer Legend The baseline case imperviousness for a project si

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试卷: LEED AP ID+C 模拟试卷A[查看]
The baseline case imperviousness for a project site is 95%. An office renovation will have site improvements to an existing asphalt pavement parking lot. The size of the parking lot is 26,134 sf. The design case materials that will be used as replacement include:

Surface ; Runoff Coefficient ; Area (sf)
Asphalt Pavement ; 0.95 ; 7,678;
Pervious Pavement ; 0.65 ; 5,086;
Vegetation, Flat ; 0.10 ; 13,370;

What is the reduction in imperviousness from the new design?
A: 50%
B: 41%
C: 43%
D: 54%

参考答案: B

本题解释:
Reference: Sustainable Sites Credit, Site Selection, Stormwater Design-Quantity Control, Calculation
Multiply each surface by the runoff coefficient to calculate the total impervious area.

Surface Runoff Coefficient Area (sf) Impervious Area (sf)

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Asphalt Pavement 0.95 7,678 7,294

Pervious Pavement 0.65 5,086 3,306

Vegetation, Flat 0.10 13,370 1,337



Total area: 26,134 sf
Total impervious area: 11,937 sf (add up all 3 columns of surfaces)
Imperviousness = total pervious area (sf) / total site area (sf)
(26,134 - 11,937) / 26,134 = 54% impervious


The baseline case had an imperviousness of 95% (stated in the question) resulting in a reduction of 41%.
Since the reduction is 41%, and the baseline case is 95%, we can calculate that the design case is 54%.
95% baseline case - 54% design case = 41%

李明

Imperviousness = total pervious area (sf) / total site area (sf)
不渗透率=总渗透面积/总用地面积？这个公式是不是错了啊？