FBO_4_Attachment_2_Guthrie_WREP_Performance_Time_Calculations.pdf

GUTHRIE, MITCHELL and DAYNA, WREP EASEMENT

WETLAND RESTORATION PROJECT

Graves County, Kentucky

PERFORMANCE TIME COMPUTATIONS

Time estimates are based on 8-hour days, five days a week.

Based on a construction unit consisting of the following:

(1) Bulldozer, (1) Trackhoe, (1) 4 WD Farm tractor with 12 cubic yard scraper pan,

(1) 2WD Farm tractor, (1) Disk, (1) Seeder, (1) Cultipacker, (1) Mulch blower,

(1) Bushhog

The work will consist of the following items:

Mobilization / Demobilization:

Estimate 0.5 days for mobilization and 0.5 days for demobilization. Total time 1.0 day.

Clearing:

Estimate 0.5 days to mow (bush hog) the marked areas and ingress/egress and other access trails (approximately 11.1 acres).

Topsoil Stripping:

The sites designated as borrow areas will be stripped so the earth below the stripping zone can be used for Dike and Ditch Plug fill. Assume the 4WD tractor/scraper pan strips and stockpiles. The earth Ditch Plug earthfill borrow areas, for an excavation depth of 0.5 foot, is (604 yd3)(27 ft3/yd3)(1/0.5 ft depth)(1 ac/43560 ft2) = 0.8 acres. Topsoil stripping will be an additional 0.5 feet deep, for a stripping volume of (604 yd3)(0.5 ft Stripping/0.5 ft Borrow) = 604 yd3. The Dike earthfill borrow areas, for an excavation depth of 1.0 foot, is (2,053 yd3)(27 ft3/yd3)(1/1.0 ft depth)(1 ac/43,560 ft2) = 1.3 acres.

Topsoil stripping will be an additional 0.5 feet deep, for a stripping volume of (2,053 yd3)(0.5 ft Stripping/1.0 ft Borrow) = 1,027 yd3.

The areas under the proposed Dike and earth Ditch Plugs will also be stripped 0.5 feet.

The area of topsoil to be stripped under the Dike is 21,397 ft2. Estimate volume to be stripped is (21,397 ft2)(0.5 ft depth)(1 yd3/27 ft3) = 397 yd3.

ATTACHMENT 2

Performance Time Computations - Guthrie WRP

Solicitation 131A2318Q0042 Hydology Restoration Guthrie WRP County of Graves, State of Kentucky

The area of topsoil to be stripped under the Ditch Plugs is 6,825 ft2. Estimate volume to be stripped is (6,825 ft2)(0.5 ft depth)(1 yd3/27 ft3) = 127 yd3. Assume that 2/3 of this area (1/3 to either side of the ditches) can be stripped with a tractor and pan, and the remaining 1/3 in and around the ditches, must be stripped with a trackhoe. The area that can be stripped with a tractor and pan is 85 yd3.

Estimate 41 trips of the tractor/scraper pan based on 482 yd3/12 yd3 per trip. Estimate a production rate based on 41 trips(5 min/trip)(1 hr/60 min)(1 day/8 hr) = 0.5 day.

The areas in and around the ditches of the earth Ditch Plugs must be excavated with a trackhoe, for a volume of 42 yd3. Assume the trackhoe bucket has a capacity of 0.5 yd3, and the trackhoe has a production rate of 1 min/load. 42 yd3(1 load/0.5 yd3)(1 min / load)(1 hour/60 min)(1 day/8 hours) = 0.2 day.

Assume Rock Check Dam / Ditch Plug earthfill borrow areas will be excavated with a trackhoe, for an excavation depth of 0.5 feet. Topsoil stripping will be an additional 0.5 feet deep, for a stripping volume of 16 yd3. Assume the trackhoe bucket has a capacity of

0.5 yd3, and the trackhoe has a production rate of 1 min/load. 16 yd3(1 load/0.5 yd3)(1 min / load)(1 hour/60 min)(1 day/8 hours) = 0.1 day.

Total time for stripping topsoil is 0.8 day. Assume 1.0 day.

Excavation/Earthfill:

The earth Ditch Plugs and Dike will be constructed using a trackhoe, 4WD tractor/scraper and bulldozer. Earth fill will come from borrow areas as designated by NRCS personnel.

There are 2,657 cubic yards of material to borrow and place in the Ditch Plugs and Dike.

Estimate 222 trips based on 2,657 yd3/(12 yd3/trip). Estimate a minimum production rate based on 8 min/trip and 222 trips: 222 trips(8 min/trip)(1 hr/60 min)(1 day/8 hrs) = 3.7 days. Additional time is required to place and compact earthfill using the trackhoe in ditches to construct earth Ditch Plugs. Use 5.0 days.

Water Control Structure Installation:

There is one 8” x 4’ inline water control structure to be installed as shown on plans. The associated components are 8 inch diameter Schedule 40 PVC pipe to install, rodent guard, trash guard, anti-seep collar, guard post, 25 tons of rock riprap, and 20 square yards of non-woven geotextile per inline water control structure. It is estimated that it will take 2 hours to install each structure and associated components, and 6 hours to backfill around structure and associated components. Total time needed is therefore 1.0 day.

Auxiliary Spillways:

The proposed auxiliary spillway will be constructed with a trackhoe and bulldozer.

Approximately 0.1 acres (< 0.5 ft depth) will be excavated per dike. Estimate excavation to take 0.5 day.

ATTACHMENT 2

Performance Time Computations - Guthrie WRP

Rock Check Dams (Ditch Plugs):

The proposed rock check dam will be constructed with a trackhoe and bulldozer. 7 yd3 will be excavated. 16 yd3 of earthfill will be placed. Estimate excavation and earthfill to take 0.5 day per rock check dam. The rock check dam will have 30 tons of Class III rock riprap and 57 square yards of non-woven geotextile installed. Estimate that rock riprap and geotextile placement take 1.0 day per rock check dam. Total time to construct rock check dams is 1.5 days.

Seeding/Mulching:

Estimate 0.5 days to seed/mulch the disturbed areas (approximately 1.0 acre).

Total: 11.0 days.

The work should be done in September. There are usually 6 adverse weather days in September. For a 11.0-day construction time starting September 10, 2018, add 4 adverse weather days, 2 Saturdays, and 2 Sundays. The total number of calendar days for this project is 19 calendar days.

ATTACHMENT 2

Performance Time Computations - Guthrie WRP