**NATURAL RESOURCES CONSERVATION SERVICE**

**CONSERVATION PRACTICE CONSTRUCTION SPECIFICATION**

**STREAMBANK AND SHORELINE PROTECTION - LOOSE ROCK RIPRAP**

**CODE 580R**

1.  **SCOPE**

> The work shall consist of the construction of rock riprap revetments
> and blankets, including geotextile or bedding where specified.

2.  **SITE PREPARATION**

> Site preparation (mobilization and demobilization, clearing and
> grubbing, structure removal, pollution control, and water for
> construction) shall be in accordance with Construction Specification
> 587.

3.  **MATERIALS**

> Bedding, if used, shall be uniformly graded rock and gravel and as
> shown on the drawings.
>
> Fibers (threads and yarns) used in the manufacture of geotextile shall
> consist of synthetic polymers composed of a minimum of 85 percent by
> weight polypropylenes, polyesters, polyamides, polyethylene,
> polyolefins, or polyvinylidene-chlorides. They shall be formed into a
> stable network of filaments or yarns retaining dimensional stability
> relative to each other. The geotextile shall be free of defects and
> conform to the physical requirements of nonwoven fabrics, Class III,
> unless otherwise specified. The geotextile shall be free of any
> chemical treatment or coating that significantly reduces its porosity.
> Fibers shall contain stabilizers and/or inhibitors to enhance
> resistance to ultraviolet light.
>
> The contractor shall certify that the geotextile meets this
> specification and shall provide information from the manufacturer
> showing that it equals or exceeds the physical properties specified
> below.
>
> ^[1]{.underline}/^ Minimum average roll value (weakest principal
> direction).
>
> ^[2]{.underline}/^ U.S. standard sieve size.
>
> ^[3]{.underline}/^ Heat-bonded or resin-bonded geotextile may be used
> for Classes III and IV. They are particularly well suited to Class IV.
> Needle-punched geotextiles are required for all other classes.
>
> The source of the rock will be approved by the engineer prior to the
> placement of the riprap. The gradation shall be as shown on the
> drawings.

4.  **FOUNDATION WORK**

> Foundation work (diverting surface water, dewatering the construction
> site, dewatering borrow areas, and foundation preparation) shall be in
> accordance with Construction Specification 587.
>
> Riprap shall not be placed until the foundation preparation is
> completed and the subgrade surfaces have been inspected and approved
> by the engineer.

5.  **EARTHWORK**

> Earthwork (common excavation and earthfill) shall be in accordance
> with Construction Specification 587.

6.  **GEOTEXTILE STORAGE AND PLACEMENT**

> When geotextile is specified beneath the rock riprap, the geotextile
> shall be stored in a clean, dry place, out of direct sunlight, not
> subject to extremes of either hot or cold, and with the manufacturer's
> protective cover in place. Receiving, storage, and handling at the job
> site shall be in accordance with the requirements in ASTM D 4873.
>
> The surface on which the geotextile is to be placed shall be graded to
> the neat lines and grades as shown on the drawings. The surface shall
> be reasonably smooth and free of loose rock and clods, holes,
> depressions, projections, muddy conditions and standing or flowing
> water.
>
> Prior to placement of the geotextile, the soil surface is to be
> inspected and approved by the engineer. The geotextile shall be placed
> on the approved prepared surface at the locations and in accordance
> with the details shown on the drawings and specified. The geotextile
> shall be unrolled along the placement area and loosely laid (not
> stretched) in such a manner that it will conform to the surface
> irregularities when material is placed on or against it. The
> geotextile may be folded and overlapped to permit proper placement in
> the designated area.
>
> The geotextile shall be joined by overlapping a minimum of 18 inches
> (unless otherwise specified) and secured against the underlying
> foundation material. Securing pins approved and provided by the
> geotextile manufacturer shall be placed along the edge of the panel or
> roll material to adequately hold it in place during installation. Pins
> shall be made of steel or fiberglass formed into a "U", "L", or "T"
> shape or contain "ears" to prevent total penetration. Steel washers
> shall be provided on all but the "U" shaped pins. The upstream or
> upslope fabric shall overlap the abutting downslope fabric. At
> vertical laps, securing pins shall be inserted through both layers
> along a line through approximately the midpoint of the overlap. At
> horizontal laps and across the slope laps, securing pins shall be
> inserted through the bottom layer only. Securing pins shall be placed
> along a line approximately 2 inches in from the edge of the placed
> geotextile at intervals not to exceed 12 feet unless otherwise
> specified. Additional pins shall be installed as necessary and where
> appropriate to prevent any undue slippage or movement of the fabric.
> The use of securing pins will be held to the minimum necessary. Pins
> are to be left in place unless otherwise specified.
>
> Should the geotextile be torn or punctured, or the overlaps or the
> joint disturbed---as evidenced by visible fabric damage, subgrade
> pumping, intrusion, or grade distortion---the backfill around the
> damaged or displaced area shall be removed and restored to the
> original approved condition. The repair shall consist of a patch of
> the same type of fabric being used, overlaying the existing fabric.
> When the geotextile seams are required to be sewn, the overlay patch
> shall extend a minimum of 1 foot beyond the edge of any damaged area
> and joined by sewing as required for the original geotextile, except
> that the sewing shall be a minimum of 6 inches from the edge of the
> damaged fabric. Geotextile panels joined by overlap shall have the
> patch extend a minimum of 2 feet from the edge of any damaged area.
>
> The geotextile shall not be placed until it can be anchored and
> protected with the specified covering within 48 hours or protected
> from exposure to ultraviolet light. In no case shall material be
> dropped on uncovered geotextile from a height greater than 3 feet.
>
> Any damaged geotextile shall be replaced and paid for by the
> contractor.
>
> As a minimum, a 3-inch layer of bedding material shall be placed over
> the geotextile prior to placing the rock riprap.

7.  **BEDDING**

> The bedding material shall be spread uniformly on the prepared
> foundation surface to the depth specified and shall be free of mounds,
> dips, or windrows. Compacting of bedding will not be required. The
> surface of the bedding shall be approved by the engineer prior to the
> placement of the rock riprap.

8.  **EQUIPMENT-PLACED ROCK RIPRAP**

> The rock shall be placed by equipment on the surfaces and to the
> depths specified. The riprap shall be constructed to the full course
> thickness in one operation and in such a manner as to avoid serious
> displacement of the underlying materials. The rock shall be delivered
> and placed in a manner that will insure that the riprap in place shall
> be reasonably homogeneous with the larger rocks uniformly disturbed
> and firmly in contact one to another with the smaller rocks and spalls
> filling the voids between the larger rocks.
>
> Riprap shall be placed in a manner to prevent damage to structures.
> Hand placing will be required to the extent necessary to prevent
> damage to the permanent works.

9.  **HAND-PLACED RIPRAP**

> The rock shall be placed by hand on the surfaces and to the depths
> specified. It shall be securely bedded with the larger rocks firmly in
> contact one to another. Spaces between the larger rocks shall be
> filled with small rocks and spalls. Smaller rocks shall not be grouped
> as a substitute for larger rock.

10. **MEASUREMENT**

> The volume of the riprap and the volume of bedding will be measured
> within the specified limits as shown on the drawings and computed to
> the nearest cubic yard by the method of average cross-sectional end
> areas. Separate measurement of geotextile will not be performed.
>
> Project Name:
>
> Date:

11. **ITEMS OF WORK AND CONSTRUCTION DETAILS**

> Items of work to be prepared in conformance with this specification
> and the construction details are: