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8-30 Water Crossings8-30 Water Crossings
8-30.1 Description
This Work consists of furnishing, mixing, and placing aggregates for streams, rivers and waterbodies of the type specified at the locations and in conformity with the lines and dimensions shown in the Plans or established by the Engineer.
8-30.1(1) Definitions
Blended Streambed Aggregate - Blended streambed aggregates are defined as a mix of the aggregates with the associated ratios in accordance with the Special Provisions or as shown in the Plans.
8-30.2 Materials
Materials for Water Crossings shall meet the following requirements: Streambed Aggregates 9-03.11 Streambed Sediment 9-03.11(1) Streambed Fine Sediment 9-03.11(2) Streambed Sand 9-03.11(3) Streambed Cobbles 9-03.11(4) Streambed Boulders 9-03.11(5)
8-30.3 Construction Requirements
8-30.3(1) General Requirements
8-30.3(1)A Streambed Preconstruction Conference
A streambed preconstruction conference shall be held at least 7 calendar days prior to the Contractor beginning streambed construction. The Contractor shall notify the Engineer 14 calendar days prior to the meeting taking place and should indicate within the notice if they intend to evaluate native streambed excavation materials for use on the project. The purpose of the meeting is to discuss the goals, objectives, intent, streambed construction procedures, construction sequence, woody material placement, critical functions during stream work, potential use of native streambed excavation materials, quality control steps to control mixing ratios, personnel, equipment to be used, and other elements of construction. Those attending shall include:
1.(Representing the Contractor) The superintendent or on-site supervisors, the Environmental Compliance Lead and other personnel or subcontractors that will have on-site responsibility for in-channel streambed Work.
2.(Representing the Contracting Agency) The Engineer, WSDOT Headquarters Hydraulics, key inspection personnel, and other key staff as appropriate will be invited by the Contracting Agency.
3.Representatives from interested permitting agencies and affected Tribes will be invited by the Contracting Agency.
8-30.3(1)B Onsite Streambed Evaluation Meeting
The onsite streambed evaluation meeting shall be held at least 7 calendar days prior to the Contractor reintroducing flows into the new channel or removal of the temporary stream diversion, whichever occurs first. The Contractor shall notify the Engineer 14 calendar days prior to the meeting taking place. The purpose of this prefinal inspection is to conduct an evaluation of the constructed streambed and Woody Material installation to ensure the work was completed in compliance with the Contract and permit requirements. M 41-10 Page 8-151 Water Crossings 8-30Those attending shall include:
1.(Representing the Contractor) The superintendent, on-site supervisors, the Environmental Compliance Lead and other personnel that will have on-site responsibility for in-channel streambed Work.
2.(Representing the Contracting Agency) The Engineer, WSDOT Headquarters Hydraulics, key inspection personnel, and other staff as appropriate will be invited by the Contracting Agency.
3.Representatives from interested permitting agencies and affected Tribes will be invited by Contracting Agency.
8-30.3(2) Mixing of Streambed Aggregates
Streambed sediment, streambed fine sediment, streambed cobbles, streambed sand, and aquitard bedding material will be separately tested and accepted by the Engineer prior to delivery, placement in a stockpile or blending activities. After acceptance by the Engineer, streambed aggregates shall be thoroughly blended before placement. Acceptance of the final mixture of blended streambed aggregate will be based upon visual inspection by the Engineer. Native streambed aggregates may be available from the existing streambed excava-tion limits as shown in the Contract Plans. Components of the excavated streambed which meet the criteria for the specific material may be used to supplement imported streambed aggregates.
8-30.3(3) Placement of Streambed Aggregates
8-30.3(3)A Stockpiling Streambed Aggregates
Streambed aggregates, as described above, shall be blended into single well graded stockpiles separate from other aggregates.
8-30.3(3)B Placing Blended Streambed Aggregates in Streambed
Blended streambed aggregate shall be placed in the prepared channel excavation to the lines and grades shown on the Plans and in such a way as to prevent material segregation. Blended streambed aggregate shall be placed in lifts no thicker than 12 inches. Blended streambed aggregate in its final location shall be a well graded mix. Placement of blended streambed aggregate shall be constructed to ensure that stream low flow rate of 30 gallons per minute is conveyed above each channel lift. The Contractor shall apply streambed sand and water at a rate of 30 gallons per minute to each lift to facilitate filling the interstitial voids of the blended streambed aggregate. Adjustment of the low flow rate may be required to ensure that the voids are satisfactorily filled. The voids are satisfactorily filled when the 30 gallons per minute flow rate does not go subsurface and there is no perceivable difference in the low flow rate from upstream of the project limits to the downstream of project limits. The Contractor shall apply water at the 30 gallons per minute flow rate to the stream channel for visual acceptance by the Engineer. Water shall be free from contaminates, chlorination and additives that have a risk on fish and other ecological life.
8-30.3(3)C Placing Blended Streambed Aggregates in Streambank
Blended streambed aggregate placed in the streambanks shall be placed in lifts no thicker than 12 inches. The Contractor shall compact each lift to be uniformly dense and unyielding as approved by the Engineer.
8-30.3(3)D Additional Streambed Grading
Changes to the streambed may be directed at the streambed evaluation meeting. Page 8-152 M 41-10
8-30 Water Crossings8-30.4 Measurement
Streambed Sediment, Streambed Fine Sediment, Streambed Sand, and Streambed Cobbles __ In. will be measured per ton. Streambed Boulders Type __ will be measured per each.
8-30.5 Payment
Payment will be made for each of the following Bid items that are included in the Proposal: “Streambed Sediment”, per ton. “Streambed Fine Sediment”, per ton. “Streambed Sand”, per ton. “Streambed Cobbles __ In.”, per ton. The unit Contract price per ton for “Streambed Sediment”, “Streambed Fine Sediment”, “Streambed Sand” and “Streambed Cobbles __ In.”, shall be full payment for all costs to perform the Work as specified including blending of streambed aggregates and watering in each lift, including supply and application of water to facilitate filling the interstitial voids. “Streambed Boulders Type __”, per each. The unit Contract price per each shall be full payment for all costs to perform the Work as specified including blending of streambed aggregates and watering in each lift, including supply and application of water to facilitate filling the interstitial voids. “Additional Streambed Grading”, by Force Account in accordance with 1-09.6. For the purpose of providing a common Proposal for all Bidders, the Contract Agency has entered an amount for the item “Additional Streambed Grading” in the Bid Proposal to become a part of the total bid by the Contractor. When native materials are approved for use, the Contracting Agency will compensate the Contractor by change order in accordance with Section 1-04.4.
Source: Washington Standard Specifications for Road, Bridge, and Municipal Construction, 2024 Edition. Pages 900–902 of 1,151.