HomeMy WebLinkAboutBID - 6006 STEWART CASE PARK IMPROVEMENTS (44)City of Fort Collins Section 02204 – Water Control and Dewatering
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DIVISION 2
SECTION 02240 - WATER CONTROL AND DEWATERING
PART 1 GENERAL
1.01 SECTION INCLUDES
A. The work of this section consists of controlling groundwater, site drainage, and storm flows during
construction. The CONTRACTOR is cautioned that the work involves construction in and around
drainage channels, local streams or rivers, and areas of local drainage. These areas are subject to
frequent periodic inundation.
1.02 RELATED SECTIONS
A. Section 02315 – Excavation and Embankments
PART 2 PRODUCTS
2.01 MATERIALS
A. On-site materials may be used within the limits of construction to construct temporary dams and
berms. The materials such as plastic sheeting, sand bags, and storm sewer pipe may also be used if
desired by the CONTRACTOR.
PART 3 EXECUTION
3.01 CONSTRUCTION REQUIREMENTS
A. General: For all excavation, the CONTRACTOR shall provide suitable equipment and labor to
remove water, and he shall keep the excavation dewatered so that construction can be carried on
under dewatered conditions where required by the Drawings and Specifications. Water control
shall be accomplished such that no damage is done to adjacent channel banks or structures. The
CONTRACTOR is responsible for investigating and familiarizing himself with all site conditions
that may affect the work including surface water, level of groundwater and the time of year the
work is to be done. All excavations made as part of dewatering operations shall be backfilled with
the same type material as was removed and compacted to 95% of Maximum Standard Proctor
Density (ASTM D698) except where replacement by other materials and/or methods are required.
The CONTRACTOR shall conduct his operation in such a manner that storm or other waters may
proceed uninterrupted along their existing drainage courses. By submitting a bid, the
CONTRACTOR acknowledges that he has investigated the risk arising from such waters and has
prepared his bid accordingly, and assumes all of said risk. At no time during construction shall the
CONTRACTOR affect existing surface or subsurface drainage patterns of adjacent property. Any
damage to adjacent property resulting from the CONTRACTOR’s alteration of surface or
subsurface drainage patterns shall be repaired by the CONTRACTOR at no additional
cost to the OWNER.CONTRACTOR shall remove all temporary water control facilities when
they are no longer needed or at the completion of the project. Pumps and generators used for
dewatering and water control shall be quiet equipment enclosed in sound deadening devices.
B. Surface Water Control: Surface water control generally falls in to the following categories:
1. Normal low flows along the channel;
2. Storm/flood flows along the channel;
City of Fort Collins Section 02204 – Water Control and Dewatering
Park Planning & Development Division Page 2 of 2
3. Flows from existing storm drain pipelines; and,
4. Local surface inflows not conveyed by pipelines.
C. The CONTRACTOR shall coordinate, evaluate, design, construct, and maintain temporary water
conveyance systems. These systems shall not worsen flooding, alter major flow paths, or worsen
flow characteristics during construction. The CONTRACTOR is responsible to ensure that any
such worsening of flooding does not occur. The CONTRACTOR is solely responsible for
determining the methods and adequacy of water control measures.
D. At a minimum, the CONTRACTOR will be responsible for diverting the quantity of surface flow
around the construction area so that the excavations will remain free of surface water for the time it
takes to install these materials, and the time required for curing of any concrete or grout. The
CONTRACTOR is cautioned that the minimum quantity of water to be diverted is for erosion
control and construction purposes and not for general protection of the construction-site. It shall
be the CONTRACTOR's responsibility to determine the quantity of water which shall be diverted
to protect his work from damage caused by storm water.
E. The CONTRACTOR shall, at all times, maintain a flow path for all channels. Temporary
structures such as berms, sandbags, pipeline diversions, etc., may be permitted for the control of
channel flow, as long as such measures are not a major obstruction to flood flows, do not worsen
flooding, or alter historic flow routes.
F. Groundwater Control: The CONTRACTOR shall install adequate measures to maintain the level of
groundwater below the foundation subgrade elevation and maintain sufficient bearing capacity for
all structures, pipelines, earthwork, and rock work. Such measures may include, but are not
limited to, installation of perimeter subdrains, pumping from drilled holes or by pumping from
sumps excavated below the subgrade elevation. The foundation bearing surfaces are to be kept
dewatered and stable until the structures or other types of work are complete and backfilled.
Disturbance of foundation subgrade by CONTRACTOR operations shall not be considered as
originally unsuitable foundation subgrade and shall be repaired at Contractor’s expense.
G. Any temporary dewatering trenches or well points shall be restored following dewatering
operations to reduce permeability in those areas as approved by the ENGINEER.
END OF SECTION