PART 1 – GENERAL A. Description
Contractor shall use appropriate Best Management Practices (BMPs) to reduce construction-related impacts and control runoffs to protect channels, storm drains, and bodies of water from pollution. The following Section applies to projects where Mesa Water is a party to the contract for the construction activities.
For projects that will disturb less than one (1) acre of land, the contractor will not be required to prepare a site-specific Storm Water Pollution Prevention Plan (SWPPP). For projects greater than one (1) acre, a site-specific SWPPP is required.
Disposal of construction water from operations such as groundwater dewatering and water used for testing, disinfecting, and flushing pipelines is not part of the work under this Section.
B. Projects Disturbing Less Than One Acre of Land
If the project disturbs less than one (1) acre of land, the contractor will not be required to prepare a site-specific Storm Water Pollution Plan (SWPPP). The contractor shall implement and maintain such BMP’s as are relevant to the work. The BMP’s can be found on the internet at http://www.cabmphandbooks.com. Appropriate BMPSs for construction-related materials, wastes, spills or residues shall be implemented to minimize transport from the site to streets, drainage facilities, or adjoining properties by wind or runoff. The contractor shall contain all wastewater or storm water runoff from the project site. This shall include, but not be limited to, the following: no placement of construction materials where they could enter storm drain system; checking construction vehicles for leaking fluids; providing a controlled area for cleaning or rinse-down activities; monitoring of construction activities; minimizing usage of water when saw-cutting and vacuum the residue; providing measures to capture or vacuum-up water contaminated with construction debris; removing any construction related debris on a daily basis; protecting work areas from erosion; sand bags at the catch basins; and desilt/filter the runoff until it meets the Clean Water Act requirements.
C. Projects Disturbing More Than One Acre of Land
For projects disturbing more than one (1) acre of land, the contractor will be required to prepare a specific SWPPP. The contractor shall develop, submit, and implement a site-specific SWPPP for the project per this Section. This Section describes the work necessary by the contractor to allow Mesa Water, for projects where Mesa Water is a party of the contract, to comply with the existing California State Water Resources Control Board (SWRCB) General Construction Activity Storm Water Permit No. CAS000002 (general permit) for discharges of storm water associated with construction activities as the permit requirements are edited to fit. Specifically, this includes the development, submittal process, and implementation of the SWPPP and a Monitoring Program (MP).
1. The contractor shall read and be familiar with all requirements contained in the general permit necessary to develop a SWPPP and MP. Attention is directed to the publication entitled "Storm Water Quality Handbooks" which have been prepared by the State and should assist the contractor in the development of the SWPPP. Copies of the handbooks may be purchased by writing the Department of Transportation, Material Operations Branch, Publication Unit, 1900 Royal Oaks Drive, Sacramento, California 95815, telephone 916/445-3520.
2. The contractor shall note that compliance with the requirements contained in the general permit may require the use of erosion and sedimentation control procedures outside the limits of immediate construction activity, and the implementation of Best Management Practices (BMP).
E. Notice of Intent
The general permit requires Mesa Water, for projects where Mesa Water is party to the contract, to file a Notice of Intent (NOI) with the SWRCB. A copy of this NOI must be included in the SWPPP.
F. Submittals
The contractor shall submit the SWPPP and MP following the procedure described for shop drawing submittals. The submittal shall address (among other items) street sweeping, placing silt fences around catch basins, containing lubricants and other equipment maintenance fluids, and covering or protecting stockpiles. Mesa Water may request a re-submittal, in whole or in part, if at any time during construction the protective measures are insufficient to control detrimental impacts of runoff.
G. Measurement and Payment
All costs to the contractor for preparing the SWPPP and MP for Mesa Water’s review and approval shall be included as part of the appropriate bid item for developing, submitting and implementing the SWPPP. In addition, the contractor shall be responsible for all of his costs associated with the implementation of the SWPPP and coordination with Mesa Water, including the installation, maintenance, and removal of erosion control practices specified in the SWPPP upon completion of the project or as requested by Mesa Water’s Representative.
These costs shall be included in the appropriate bid amount as noted above.
PART 2 – MATERIALS
A. Storm Water Pollution Prevention Plan
The contractor shall develop a site-specific SWPPP in accordance with the requirements specified in the general permit. The site-specific SWPPP shall be prepared by a qualified SWPPP developer (QSD) as defined by the Construction General Permit (CGP).
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found on the internet at:
http://www.swrcb.ca.gov/water_issues/programs/stormwater/constpermits.shtml
Prior to commencing the work, the contractor shall electronically submit the required Permit Registration Documents (PRDs) to Mesa Water. If any of the required items are missing, the PRD submittal is considered incomplete and will be rejected.
Upon receipt and acceptance of a complete PRD submittal, Mesa Water will designate the contractor’s QSD through the Stormwater Multi-Application Reporting and Tracking System (SMARTS) to submit the project information on Mesa Water’s behalf. The contractor’s QSD will electronically submit these documents through SMARTS to the State Water Resources Control Board (SWRCB) to obtain coverage under the CGP.
The SWPPP shall be developed and updated using Section 2 and Appendix B of the California Stormwater Quality Association (CASQA) Stormwater Best Management Practice Handbook Web Portal for Construction (requires subscription to access). The CASQA Construction BMP Web Portal required subscription can be purchased from CASQA and can be accessed at the following link:
https://www/casqa.org/LeftNavigation/BMPHandbooksPortal/tabid/200/Default.aspx
The contractor shall implement, maintain and amend the SWPPP as needed during the course of the work to reflect actual construction progress and construction practices. Mesa Water will designate a Qualified SWPPP Practitioner (QSP), as defined by the CGP, who will be responsible for confirming the compliance with CGP requirements on the project at all times.
The SWPPP shall not be construed to be a waiver of the contractor’s obligations to review and understand the CGP before submitting a bid. By submitting a bid, the Contractor acknowledges that he has read and understands the requirements of the CGP.
The Contractor shall be responsible for and shall submit to Mesa Water copies of all contractor generated SWPPP documents, including all sampling test results, inspection reports, Rain Event Action Plans (REAP), annual reports, and other time sensitive documents involving monitoring data. Such documentation shall be provided as soon as the information is available and shall be provided within twenty-four (24) hours when requested by Mesa Water. The contractor shall be required to produce such data and documentation at the project site on demand if so requested by the RWQCB during a site inspection.
The contractor shall be responsible to prepare and submit the following, as a minimum:
Notice of Intent (NOI), Risk Assessment, Site Map, SWPPP, the Notice of Termination (NOT), and the required components of the PRD.
B. Monitoring Program
The contractor shall develop an MP in accordance with the requirements specified in the general permit.
A. General
1. The SWPPP and MP shall be developed and submitted by the contractor and accepted by Mesa Water prior to commencement of construction activities.
2. The contractor shall comply with all conditions identified in the general permit, which could apply to the work under this contract.
3. The contractor shall be responsible for the compliance of his personnel and subcontractors with the SWPPP and for cooperation with Mesa Water in the implementation of the MP.
4. The SWPPP shall be kept on site during construction activity and made available upon request of a representative of the Regional Water Quality Control Board (RWQCB) and/or other regulatory agency.
5. The contractor shall amend the SWPPP whenever there is a change in construction or operations which may affect the discharge of significant quantities of pollutants to surface waters, groundwaters, or a municipal storm sewer system.
B. Removal from Service of Existing Mains and Appurtenances
The SWPPP shall provide a description of potential sources which are likely to add significant quantities of pollutants to storm water discharges or which may result in non-storm water discharges from the construction site. A description of the items required to be included in the SWPPP is included in the general permit under Section A, "Storm Water Pollution Prevention Plan."
C. Monitoring Program
1. The contractor shall develop an MP as identified in the general permit under Section B, "Monitoring Program and Reporting Requirements."
2. Mesa Water will implement the MP developed by the contractor once the District accepts all of the work under this contract; however, until the final acceptance of the work, the contractor shall be responsible for monitoring his actions and the activities of those responsible to the Contractor.
3. At any time the contractor shall allow representatives of Mesa Water, RWQCB, and/or other regulatory agencies to enter upon the construction site, inspect the construction site for compliance, and sample and monitor the construction site discharges.
4. If the MP extends past the completion date for the contract, the contractor’s responsibilities for the MP will cease upon acceptance by Mesa Water of all work under the contract.
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1. The contractor shall comply with all conditions identified in the general permit and the SWPPP. Non-adherence with the conditions specified in the general permit may constitute a violation of the Clean Water Act and the Porter-Cologne Water Quality Control Act, and may be grounds for enforcement action by the RWQCB. Any fines incurred by Mesa Water due to the contractor’s lack of compliance with the SWPPP, shall be back-charged by Mesa Water to the Contractor.
2. The contractor shall take all reasonable steps to minimize or prevent any discharge in violation of the general permit.
E. Compliance Certification
1. An officer or other authorized representative of the contractor shall certify in writing to Mesa Water annually and at the completion of construction, if it occurs before the next annual report, that its construction activity is and has been in compliance or has been modified to comply with the requirements of the general permit and the SWPPP.
2. If the contractor determines that he cannot certify compliance with any of the general permit and SWPPP requirements, he shall notify Mesa Water immediately. The notification shall identify the type of noncompliance, describe the actions necessary to achieve compliance, and include a time schedule when compliance will be achieved. Each noncompliance notification to Mesa Water shall be submitted within 15 days of identification of the event by the contractor.
END OF SECTION
DEWATERING
PART 1 – GENERAL A. Description
This section includes the general requirements for providing all labor, equipment, materials to perform all of the work necessary to design, construct, operate and maintain effective dewatering system(s) to assure a safe and dewatered condition of all areas on which the work will be performed.
The contractor shall continue the operation of the dewatering system(s) as required to complete the work and to protect adjacent property or construction until danger of damage resulting from the rise and fall of groundwater and/or inflow of surface water is precluded.
The contractor shall remove or relocate the equipment when it is no longer required, or as approved well points and like items may be abandoned in place in accordance with all laws and regulations.
B. Related Work Specified Elsewhere
1. Trenching, Backfilling, and Compacting: 02223.
C. Statutory Requirements
The California Regional Water Quality Control Board governs the discharge of any groundwater or inflow of surface water to a storm drain system. The contractor will not be authorized to discharge groundwater, pipeline dewatering, or water for pressure testing or flushing to the storm drain without obtaining a General Water Discharge Permit for Groundwater Remediation and Dewatering Waste Discharges from the Regional Water Quality Control Board. The contractor will be required to obtain and pay for any NPDES permit required for the temporary dewatering and surface drainage control discharges to a storm drain facility. The NPDES permit shall be prominently displayed on the site prior to constructing dewatering and surface water discharge operations.
D. Quality Assurance
The contractor shall furnish the services of an experienced, qualified and equipped dewatering subcontractor to design and operate the dewatering system(s) required for the work. In lieu of the above, the contractor can implement the dewatering in accordance with a system designed by a Civil Engineer who is registered in the State of California who has a minimum of five (5) years of professional experience in the design and construction of dewatering systems.
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Contractor shall submit a dewatering submittal showing the intended work plan for dewatering operations. The dewatering plan shall include drawings, and data showing the planned method of dewatering, excavation plan, location and capacity of such facilities as dewatering wells, well points, pumps, sumps, collection and discharge lines, standby units proposed, and protective fills and ditches required for control of groundwater and surface water. Included within the plan shall be a summary of the monitoring and settlement measuring equipment, and data collection and dissemination procedures. The submittal will be for information purposes only.
Review by Mesa Water will not relieve the contractor of the responsibility for the adequacy of the dewatering and excavation plan or for furnishing all equipment, labor, and materials necessary for performing the various parts of the work. The dewatering submittal shall be submitted not less than thirty (30) days prior to start of dewatering.
If, during the progress of the work, it is determined in the field that the dewatering system and excavation plan are inadequate or the contractor’s plan of construction is inoperative, the contractor shall, at his own expense, furnish, install, and operate such additional dewatering equipment and make such changes in other features of the plan or operation as may be necessary to perform the work in a manner satisfactory to Mesa Water or the agency with jurisdiction.
F. Definitions
Where the phrase “in-the-dry” is used in this Section, it shall be defined as in situ soil moisture content of no more than two (2) percentage points above the optimum moisture content for that soil.
PART 2 – MATERIALS
The contractor shall furnish and maintain all materials, tools, equipment, facilities and services as required for providing the necessary dewater work and facilities. Dewatering may include the use of gravel filled trenches, sumps, well points, sump pumps, temporary pipeline for water disposal, rock or gravel placement, and other means.
The contractor shall provide sufficient pumping equipment and machinery in good working condition and have available, at all times, competent workmen for the operation of the pumping equipment.
Adequate standby equipment shall be available at all times to insure efficient dewatering and maintenance of dewater operation during power failure.
PART 3 – EXECUTION A. General
1. Control surface water and groundwater such that excavation to final grade can be made in-the-dry, and bearing soils are maintained undisturbed. Contractor shall prevent softening, or instability of, or disturbance to, the subgrade due to water seepage.
3. The impact of anticipated subsurface soil/water conditions shall be considered when selecting methods of excavation and temporary dewatering and surface water control.
Where groundwater levels are above the proposed bottoms of excavations, a pumped dewatering system is expected for pre-drainage of the soils prior to excavation to final grade and for maintenance of the lowered groundwater level until construction has been completed to such an extent that the foundation, structure, pipe, conduit, or fill will not be floated or otherwise damaged. Type of dewatering system, spacing of dewatering units and other details of the work are expected to vary with soil/water conditions at a particular location.
B. Surface Water Control
Control surface water runoff to prevent flow into excavations. Contractor shall provide temporary measures such as dikes, ditches, and sumps, as required.
C. Excavation Dewatering
1. Provide and maintain adequate equipment and facilities to remove promptly and dispose of properly all water entering the excavation. Excavations shall be kept in-the-dry, so as to maintain an undisturbed subgrade condition throughout construction below grade, including backfill and fill placement.
2. Collect precipitation or surface runoff in shallow ditches around the perimeter of the excavation, drain to sump and pump from the excavation to maintain in-the-dry conditions.
3. Pipe and conduit shall not be installed in water or allowed to be submerged prior to backfilling. Pipe and conduit which becomes submerged shall be removed and the excavation dewatered and restored to proper conditions prior to reinstalling the pipe and conduit.
4. Excavations for foundations and structures shall be maintained in-the-dry for a minimum of four (4) days after concrete placement. In no event shall water be allowed to enter an excavation and rise to cause unbalanced pressure on foundations and structures until the concrete and mortar has set at least 24 hours.
5. Dewatering and surface water control operations shall at all times be conducted in such a manner as to preserve the natural undisturbed bearing capacity of the subgrade at the bottom of the excavation. If the subgrade becomes disturbed for any reason, the unsuitable subgrade material shall be removed and replaced with compacted granular fill, or other approved material to restore the bearing capacity of the subgrade to its original undisturbed condition.
6. Dewatering and surface water control operations shall be conducted in a manner that does not cause loss of ground or disturbance to the pipe bedding or soil that supports overlying or adjacent structures.
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other portion of any new or any existing facilities or structures caused by permanent or temporary failure or operation of the dewatering or by failure to maintain the existing groundwater level outside the dewatering areas.
D. Testing and Field Quality Control
Contractor shall observe and record the elevation of the groundwater on a 12-hour or less interval during the period that the dewatering system is in operation.
E. Disposal of Drainage
All water discharged from the temporary dewatering and surface control shall be disposed of in accordance with project permits. Dewatering of non-contaminated or contaminated groundwater via surface erosion is prohibited. All dewatering of groundwater shall be discharged to the nearest sewer facility. Prior to using existing sanitary sewer systems for disposal, the contractor shall obtain written permission of the owner of the sewer. The
All water discharged from the temporary dewatering and surface control shall be disposed of in accordance with project permits. Dewatering of non-contaminated or contaminated groundwater via surface erosion is prohibited. All dewatering of groundwater shall be discharged to the nearest sewer facility. Prior to using existing sanitary sewer systems for disposal, the contractor shall obtain written permission of the owner of the sewer. The