- 126 - SECTION 204 -- TEMPORARY WATER POLLUTION CONTROL
204.01 Description
1.This Section defines some te mporary measures and construction practices the Contractor shall use to prevent soil erosion and avoid water pollution.
2.The Contractor shall exerci se every reasonable precaution throughout the life of the contract to prevent silt ing of rivers, streams, impoundments (lakes, reservoirs, etc.), the project site, and adjacent property. Construction of drainage facilit ies, as well as performance of other contract work which will contribute to t he control of siltatio n, shall be carried out in conjunction with earthwork oper ations or as soon thereafter as is practicable.
3.a. The Contractor shall take sufficient precautions to prevent pollution of streams, lakes, reservoirs , the project site, and adjacent property with petroleum products, chemicals, or other harmful materials.
b.The Contractor shall conduct and schedule the operations so as to avoid interference with movement of migratory fish.
c.The Contractor shall comply wi th all applicable statutes relating to pollution of streams and fish and game regulations.
4.All construction debris shall be disposed in a manner that it cannot enter any waterway. Waste excavation from the roadway, channel changes, cofferdams, etc., shall not be deposited in or so near to rivers, streams, or impoundments that it will be washed away by high water or runoff.
5.The Contractor's erosion contro l measures shall be continued until the permanent drainage facilities have been constructed and the grass on seeded slopes is sufficiently establishe d to be an effective erosion deterrent or until tentative acc eptance of the work.
6.All erosion control measures s hall be properly maintained by the Contractor.
7.All erosion resulting from t he Contractor's operations and the elements must be corrected by the Contra ctor at no additional cost to the Department.
8.The Contractor shall explain hi s/her erosion control plans at the preconstruction conference.
204.02 Limitation of Operations
1.The maximum exposed surface area for the Contractor's operations in excavation, borrow, and embankment is 18 acres (72,800 m2) plus an equal area of clearing and grubbing/large tree removal. A written request for an increase in the maximum exposed surface area may be approved by the Engineer. This approval will be based on the soil, moisture, seasonal conditions, the Contractor’s op eration, or other conditions.
2.a. The Engineer shall have the authority to reduce the maximum exposed surface area when any of the following conditions warrant:
1.Soil and moisture conditions are such that erosion is probable.
2.Seasonal conditions may force extended delays. Temporary Water Pollution Control 204.03 - 127 - (3) Proximity to lakes, str eams, ponds, or other watercourses require more stringent controls.
4.Equipment available on the job is not sufficient to properly handle areas that are opened.
5.Any other environmental condition in the area exists which would be affected by erosion from the project.
b.The Contractor shall i mmediately provide permanent or temporary erosion control measures as outlined when any of these above conditions exist.
3.Construction operations in rive rs, streams, and impoundments shall be restricted to those areas where channel changes are shown in the contract and to those areas which mu st be entered for the construction of temporary or permanent structures or embankments, unless the Engineer issues a written approval of deviati on. Rivers, streams, and impoundments shall be promptly cleared of all falsewor k, piling, debris, or other obstructions placed therein or caused by the construction operations.
4.Frequent fording of live stream s with construction equipment will not be allowed; therefore, temporary bridges or ot her structures shall be used wherever an appreciable number of stream crossings are necessary. Unless otherwise approved in writing by the Engineer, mechanized equipment shall not be operated in live streams except as may be required to construct channel changes and temporary or permanent structures.
204.03 Construction Methods
1.a. The Contractor shall conduct all construction activities so as to avoid soil erosion.
b.Each day, slopes shall be graded so that storm runoff will not erode soil.
c.Diversion ditches shall be cut to direct the runoff flow.
2.The Contractor shall incorpor ate all permanent erosion control features, including cover crop seeding, into the project at the earliest practicable time as outlined in his/her schedule. "Temporary Water Pollution Control" will be used to correct the following:
a.Conditions that develop du ring construction that were not foreseen during the design stage.
b.Conditions that exist befor e installation of permanent pollution control features.
c.Temporary erosion cont rol problems that develop during construction but are not associated wi th permanent control features on the project.
3."Temporary Water Pollution Contro l" may include but is not limited to berms, dikes, dams, sediment basins and other erosion c ontrol structures necessary to control erosion until such time as the grading is complete and permanent erosion control can be placed as shown in the contract. It excludes berms, dikes, dams, sediment basins, temporary slope drains, mulching, cover crop seeding, silt fences, lined hay-bale diversion ditches, slope stabilization mats, and other eros ion control structures shown in the contract which shall be separate pay items.
204.03 Temporary Water Pollution Control
- 128 - 4. Necessary construction work outside the right-of-way, such as borrow pit operations, haul roads, plant sites, and equipment storage sites, shall include temporary pollution control. All pollution control requirements outside the right-of-way are subsidia ry to the item being constructed.
5.a. The temporary pollution cont rol procedures contained herein shall be coordinated with any permanent erosion control structure or direct payment item specified elsewhere in the contract to the extent practical to assure economical, effective, and conti nuous erosion control throughout the construction period.
b.The Contractor shall be responsible for evaluating the construction site and determining the need for and installing additional permanent erosion control structures not shown in the contract (such as sediment traps, silt fenc e, ditch checks, etc.)
6.The Contractor shall also provide such measures, including dikes and berms, to limit erosion and siltat ion into streams, rivers, or other impoundments during the construction period, as well as during the times that work may be suspended.
204.04 Method of Measurement
1.Measurements will not be made for "Temporary Water Pollution Control".
204.05 Basis of Payment
1."Temporary Water Pollution Control" is subsidiary to the item being constructed.
2.The work identified in Subsection 204.03, Paragraph 5.b., shall be paid for either at contract unit prices or as "extra work", provided that the Engineer is notified and approves each item in writing prior to the work being performed. - 129 - SECTION 205 -- EXCAVATION AND EMBANKMENT
205.01 Description
1.Excavation and embankment work is usually enacted by four different pay items, "Excavation", "Excavation (Established Quantity)", "Excavation Borrow", and "Earthwork Measured in Embankment". The requirements for each pay item are described in Tables 205.01A and B. Table 205.01A Excavation/Embankment Pay Item Requirements Pay Items (See Notes 1, 2) Measured Quantity Established Quantity Work Description Code Excavation Excavation Borrow Excavation (EQ) Earthwork Measured in Embankment A X X B X X C X X X X D X X X X E X X X X F X X X X G X X X X H X X X X I X X X X J X X K X X L X X M X X X N X 1 Excavation borrow is only used when part or all of the embankment material must be obtained off-site. 2 Earthwork-Measured-in-Em bankment may be used when the project requires off-site borrow; it is also used on projects where all embankment soil is available on-site.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 160–162 of 1,048.