**NATURAL RESOURCES CONSERVATION SERVICE**

**Idaho**

**CONSTRUCTION SPECIFICATIONS**

**FOR**

> **GRASSED WATERWAY**

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(Owner/Operator)

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(Project/Title)

GENERAL

Installation shall be in accordance with an approved design and plan.
Details of construction shown on the drawings but not included herein
are considered as a part of this specification.

Construction operations shall be carried out in a manner to ensure that
erosion and air and water pollution are minimized. Construction
activities shall be in accordance with applicable OSHA regulations.

Plan to construct waterways during years when the majority of fields in
the watershed above the waterway are in high residue producing crops
such as hay, small grains or cover crops. Also, plan farming and tillage
practices on fields adjacent to waterway that will reduce runoff into
the waterway during the vegetative establishment period.

SITE PREPARATION

Trees, brush, stumps, and other obstructions, unless otherwise shown on
the drawings, shall be removed and be disposed of so they will not
interfere with construction or proper functioning of the waterway or
outlet.

EARTHWORK

Waterways and outlets shall be constructed or shaped to equal or
slightly exceed the dimensions as shown on the plans or staked in the
field. All earth removed and not needed in construction of the waterway
shall be spread or disposed of so it will not interfere with surface
water from flowing into the waterway. The filling of gullies and washes
shall be in layers of 4 to 6 inches and compacted to prevent unequal
settlement. Over excavate and cover subsoil

areas exposed during shaping with a 4-inch layer of compacted topsoil.

After shaping, smooth the waterway to allow seedbed preparation without
further grading.

When conditions do not permit plant establishment adequate to control
erosion prior to the onset of winter, furrows may be plowed on both
sides of the waterway to keep runoff from entering the waterway during
the first winter. Side furrows will be filled in once the waterway
vegetation is established.

VEGETATIVE SPECIFICATIONS

Seedbed Preparation. Prepare a clean, firm seedbed. Final seedbed will
be firm enough so a person\'s heel will sink from 1/2 to 3/4 inch when
walking over the waterway.

Time of Seeding. Plant grasses any time moisture is adequate for plant
establishment. Plant legumes during frost-free periods shown in
ADDITIONAL SPECIFICATIONS, and when moisture is adequate for plant
establishment.

Seeding mixture. Use an adapted species or mixture from Table I unless
otherwise shown in ADDITIONAL SPECIFICATIONS. A cover crop may be used
when needed to help control erosion. Cover crops will be planted at a
rate of less than eight (8) plants per square foot.

Method of planting. Drill seed 1/4 to 1/2 inch deep. The drill spacing
will not exceed eight (8) inches. Seed will be drilled in two passes,
the first up and down the waterway, the second in a zigzag or serpentine
pattern back and forth across the waterway. Nurse crops will be drilled
in a separate seeding operation.

Fertilizer. Where annual precipitation exceeds 14 inches, fertilize with
20 pounds Nitrogen and 20 pounds Phosphorus per acre at planting.

Mulching. Unless otherwise specified mulching shall be applied as
follows:

[Material]{.underline} [Minimum Amount to Apply]{.underline}

Straw 3 tons/ac

Hay 3 tons/ac

Sawdust 7 tons/ac

NETTING

After completion of the seeding, erosion control netting shall be
installed along the waterway centerline, unless otherwise specified on
the drawings or ADDITIONAL SPECIFICATIONS. The minimum width for the
installed netting shall be as shown on the drawings. The netting may be
any commercially available product unless otherwise specified. The
netting shall be anchored on the sides, at splices, and at other
locations as per manufacturer recommendations with pins or staples.

MAINTENANCE

After establishment, fertilize and mow as needed to maintain a thick
sod. Perform tillage operation adjacent to the waterway in a manner that
will not build dikes or berms or ditches along the edges of the
waterway.

ADDITIONAL SPECIFICATIONS