|
<br />I
<br />
<br />
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />II
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />f
<br />I
<br />
<br />9.7,01
<br />
<br />Table 9 (Continued)
<br />
<br />BMP Type Typical Cost' Notes Annual Maintenance Cost
<br /> ($/cf) (% of Construction Cost)
<br />Bioretention 5.87 Bioretenfion is relatively constant in cost 5%-7'%,
<br /> because it is usually designed as a
<br /> constant traction of the total drainage
<br /> cost.
<br />Grass Swale 0.55 Based on cost per square foot, 5%.7%
<br /> assuming 6 inches of storage in filfer.
<br />Filter Strip 0-1.44 Based on cost per square foot, $320/acre (maintained)
<br /> assuming 6 inches at storage in fhe tilter
<br /> strip. The lowest cost assumes that the
<br /> buffer uses exisfing vegefation, while
<br /> highest cost assumes that sod was used
<br /> to establish the filter strip.
<br />
<br />* .
<br />Typlcal cost base for all data: August, 2001
<br />
<br />While detention ponds have an initial high cost for construction, their annual
<br />operation and maintenance cost is among the lowest of alternatives. Table 10
<br />illustrates the capital cost estimate for the proposed treatment ponds. Also
<br />provided in the table i~ the unit cost per cubic foot of pond storage. The
<br />USEP A cost is taken from the aforementioned document unit cost.
<br />
<br />Table 10
<br />Cost Estimate Comparison for Proposed Treatment Ponds
<br />
<br /> Capital Cost' Costlc.f. O&MCost'
<br />POND SEH USEPA SEH USEPA
<br />2 $260,468 $0.54 $251,503 $1.300 $2,490
<br />3 $337,009 $0.53 $310,570 $1,685 $3,075
<br />4 $337,009 $0.53 $310,570 $1,685 $3,075
<br />5 $239.369 $0.54 $234.569 $1,197 $2,322
<br />6 $190,416 $0.55 $192,642 $952 $1,907
<br />7 $337.009 $0.53 $310,570 $1,685 $3,075
<br />8 $146.885 $0.56 $155,690 $743 $1,541
<br />9 $293,743 $0.53 $277,602 $1,469 $$2.748
<br />10 $146,885 $0.56 $155,690 $734 $1,541
<br />11 $149,619 $0.56 $158,160 $748 $1,566
<br />12 $239,369 $0.54 $234,569 $1,197 $2,322
<br />Totals: $2,667,780 $2.592.135' $13,386 $21.373
<br />
<br />1. Capital Cost iucludes engineering and construction expenses. Land cost not included.
<br />2. Includes annual inspection, weed con trot, etc. SEH estimate is based upou 0.5% of construction cost. while USEPA
<br />estimate is based upon 0.99% of construction cost.
<br />3. Capital Cost difference is $75.645 or 2,8%.
<br />
<br />City of Arden Hills, Minnesota
<br />Local Stormwater Management Plan
<br />
<br />A,ARDEN0101.00
<br />Page 46
<br />
|