FLOOD06516

• County: Boulder
• Stream Name: Dry Creek
• Basin: South Platte
• Title: Dry Creek Flood Proofing Project
• Date: 1/23/1998
• Prepared For: CSCB
• Floodplain - Doc Type: Project

JAN 23 '98 02:24PM PLNG DIV OMAHA DIST ACOE

P.6/6

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Lev.es.IWO (eet above ground level .....................................................................$ 34 per IiOelar fool
lAv..s, four feel above ground level.............................................................."...... $ 63 pc:r linear fOOl
LeveclS. silt reel above ground level...........................................................,............$I05 pc:r linear fOOl

Levee costS induJe landscaping. Addirlonal COStS rhaf may 'Ired ro bt t.lI/matedfo/' hothfloodwalls and
levees are asfo/lows:

Inlerior Drainage.. ........ ......................................... ......... ........... ....... ...... ........ ......... $3.800 lump sum

Closures ...............................................................".................................................5 66 pelr square fOOl
Rlprap ........................................................................"........................................... $ 28 per cubic fOOl
Sidewalk .............................................,..................:................................................ $ 9 per linear fOOl
Orivewa)' (Asphalt) ................................................................................................$ 6 per square yard
Orinwa)' (ConcIele) ..............................................................................................$ t6 per square yard

Dr)' Flood Proolinll

Sprayed-on cement (l18 inch) .................................................................................$ 3 per square root
Asphall (2 COalll below grade) ................................................................................$ I per square fool

Periphery drainage ..................................................................................................$ 28 per linear fOOl
Plumbing check valve (6") .....................................................................................$600 lump sum
Pump (submersible sump) ......................................................................................$500 lump sum
Flood shields

Metal...............................................,................................................................$ 66 per square fool
Wood ...............................................................................................................$ 21 per square rool

For purposes of this analysis, the costs (or various flood proo(mg methods listed above can be used as an
initial planning estimate. For the example hOlllll, the unit cost of $33 per square foot for raising an
existing slab-on-grade suucrure is appropriate. The example home measured 30 feet by 42 feet for a
total floor space of 1,260 sq1,Ul[e feel. Thus, Ihe estimated cost 10 elevate the example home was
$41,580. To place fill under the elevated home, the unil cost of $10 per cubic yard was used. The
amount of (ill, based on a I vertic:al1O 3 horizontal side slopes and elevating the building 5 feet. was 969
cubic yards for an estimated fiU cost of $9,690. See Figure A-16 on page A-21. Landscaping was esti-
mated at $5 per square yard for 344 square yards with a cost of $1.720. Costs for addition.alliving
expense during time away from the home were based on five days and three persons ($670)_ Loss of
income was estimated for three days at $200 per day ($600). This loss involved the time away from the
homeowner's job 10 cIeal with the engineering and constrUCtion contracts for the flood proofing measure.
A location adjustmem factor of 1.13. obtained from Means Constructions Costs publications, gave a sub.
total cost of $61,314. A profit of 10% also needed to be included. as well as engineering costs of $7.000.
Thus, the total cost of this flood proofing project was estimated to be $74,445. Maintenance costs were
viewed as minimal and nOI included. When compared to the present value ($108,700) of the estimated
damage prevented over the life of the StruClure, this estimated cOSI of flood proofmg would be economi-
cally justified. This information and other factors discussed in the main lext motivated the homeowner 10
a more in-depth assessment of flood proofmg.

II ETAtLED EsTIMATES OF FLOOD PROOFING COSTS

At this stage, propetty owners should oblain at leaslIhree cost estimales for flood proofing
from different contraClors. Owners should keep in mind that Ihe contractor submilting the
lowest bid may not be beSI qualified to do the work. An)' contractor bid represems cost estimates onl)';
special siluations may arise during the course of work thaI may alter actual costs incurred. Conditions
for llCIditional COSts should be covered in the signed conslruction contracl. In addition 10 the initial costs.

A-20

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