Sizing Your Rain Garden

 

Once you have determined the total impermeable drainage area for your rain garden, use the following chart to determine possible rain garden dimensions. Dimensions are given for ponding depths of 6 inches and 3 inches.

 

Impermeable Surface Area

Required Size of Rain Garden

(6” deep)

Potential Rain Garden Dimensions

(ftXft)

Required Size of Rain Garden

(3” deep)

Potential Rain Garden Dimensions

(ftXft)

800 ft 2

40 ft 2

4X10, 5X8, 6X7

80 ft 2

7X12, 8X10, 9X9

1000 ft 2

50 ft 2

5X10, 6X8

100 ft 2

7x15, 10X10

1200 ft 2

60 ft 2

4X15, 5X12, 6X10, 8X8

120 ft 2

10X12, 8X15

1400 ft 2

70 ft 2

5X14, 7X10

140 ft 2

10X14, 7X20

1600 ft 2

80 ft 2

7X12, 8X10, 9X9

160 ft 2

8X20, 10X16

1800 ft 2

90 ft 2

6X15, 7X13, 8X12, 9X10

180 ft 2

9X20,10X18,12X15

2000 ft 2

100 ft 2

7x15, 10X10

200 ft 2

10X20, 14X15

2500 ft 2

125 ft 2

8X16,10X13

250 ft 2

10X25, 13X20, 15X17

3000 ft 2

150 ft 2

10X15, 12X13

300 ft 2

10X30, 15X20

3500 ft 2

175 ft 2

9X20, 12X15

350 ft 2

14X25, 18X20

4000 ft 2

200 ft 2

10X20, 14X15

400 ft 2

16X25, 20X20

5000 ft 2

250 ft 2

10X25, 13X20, 15X17

500 ft 2

20X25

 

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