Bio-Engineering.doc

NATURAL RESOURCES CONSERVATION SERVICE

CONSTRUCTION SPECIFICATION

BIO-ENGINEERING

1.

SCOPE

This work shall consist of identifying, supplying, and planting dormant live cuttings of the species indicated on the plant list at the locations and spacing shown on the Drawings. Work includes identifying, harvesting, storage, and delivery to the construction site for plantings.

2A.

MATERIALS

A. Fascines

Cuttings will come from shrubs and young trees and will have branch diameters of less than or equal to 1 1/2 – inches at the basal end.

2.

Include at least one of the species listed in Section 5 B.

B. Live Branches

1. Cuttings will come from shrubs and young trees and will have basal branch diameters of 0.25 to 1 inch. Each stem shall contain at least two healthy side branches; side branches shall not be trimmed off.

2. Species listed in Section 5 C (3.) Group 1 are preferred. Species from Group 2 are acceptable when insufficient quantities of the preferred species are available.

C. Live Stakes

1. Cuttings will come from willow shrubs and young trees and have basal ends 1 to 2 inches in diameter.

2. Include at least one of the species listed in Section 5 B. (Group 1).

D. Collect cuttings during the dormant season (approximately two weeks after leaf-off) and deliver to the project site as soon as possible.

E. Plant material showing desiccation, abrasion, sun-scalded injury, disfigurement, or unauthorized substitution shall be rejected.

2B.

MISCELLANEOUS MATERIALS

A.

Coir Fabric

1. Coir fabric, also referred to as a natural geotextile, is made of 100% woven, coconut husk, biodegradable, organic fiber material. It is a flat fabric with non-shifting square mesh, consisting of coir yarns in both the warp and weft.

2. Coir 400 shall be least 55 weft threads per linear yard and corresponding greater density of threads warp wise. The tensile strength shall be 51 lbs./in. dry and 38 lbs./in. wet per ASTM D 4595-86. The weight shall be a minimum of 11.8 oz./sq. yd. or 400 grams/sq. meter. The open area of the fabric shall be sixty-five percent. (65%).

3. Coir 700 shall be at least 64 weft threads per linear yard and corresponding greater density of threads warp wise. The tensile strength shall be 112 lbs./in. dry and 86 lbs./in. wet per ASTM D 4595-86. The weight shall be a minimum of 20 oz./sq. yd. or 700 grams/sq. meter. The open area of the fabric shall be fifty percent (50%).

4. Coir 900 shall be at least 96 weft threads per linear yard and corresponding greater density of threads warp wise. The tensile strength shall be 59 lbs./in. dry and 138 lbs./in. wet per ASTM D 4595-86. The weight shall be a minimum of 26 oz./sq. yard. Or 900 grams/sq. meter. The open area of the fabric shall be thirty-nine percent (39%).

B.

Dead Stout Stakes

Stakes shall be 18 inches long, wedge-shaped stakes cut diagonally from 2 x 4” untreated timbers.

C. In-Situ Soils

In-situ soils proposed for tilling, amending and conditioning shall be free from slag, cinders, stones, lumps of soil, sticks, roots, trash or other materials over a minimum 3 inch diameter. In-situ soils shall be free from viable plants and plant parts.

D.

Burlap Fabric

Burlap fabric shall have a minimum weight of 10 oz./sq. yd. and be provided raw. Burlap bales shall have a minimum width of 36 inches.

E.

Twine

Twine used for tying live branch cuttings in fascines shall be natural jute twine or an approved equal. Twine shall be untreated and free from preservatives.

3.

PRODUCT HANDLING

A.

General: Carefully pack dormant live cuttings (with all growing tips in one direction) to prevent desiccation, breaking, damage to bark and branches. Provide adequate ventilation. Protect from sun, drying wind and freezing. Do not drop cuttings from vehicles. Legibly label cuttings with correct botanical name, common name, and date collected.

B.

Transport: Transport cuttings in covered, unheated vehicles, moistened and covered with moisture retaining medium.

C.

Storage:

1. If cuttings cannot be delivered to the construction site within 24 hours, store off-site in specially prepared facilities specifically constructed to store dormant live plant material. Maintain facilities at a constantly cool temperature (34 deg F to 50 deg F) and with adequate humidity levels.

2. Keep cuttings moist and covered with moisture-retaining medium throughout the time in storage. Periodically water to maintain moisture levels. While at construction site, ensure plants are not left in sun to dry out; keep in shaded area and keep moist.

3. Store on pallets above ground surface. Provide adequate ventilation.

4.

SOURCE OF SUPPLY

Harvest cuttings during the dormant season from within the project watershed, as designated or approved by the Contracting Officer. Any necessary harvesting permits are the responsibility of the contractor.

5.

DORMANT LIVE CUTTINGS

A. Notify the Contracting Officer 72 hours prior to harvesting at the approved sites.

The Contractor shall schedule his cutting and delivery to the planting site so that the materials can be installed within 48 hours after they arrive.

1. Collect only specimens deemed suitable for harvesting.

2. Harvest cuttings during the dormant season (November 1 to March 1) only.

3. Substitutions will not be permitted without written request and approval from the Contracting Officer.

B.

Live Fascines

Species

Group 1 (Recommended)

Scientific Name

Common Name

Salix interior

Sandbar Willow

Salix discolor

Pussy Willow

Salix purpurea

Purpleosier Willow ”Streamco”

Salix x cottetii

Dwarf Willow “Bankers”

Cornus stolonifera

Red Osier Dogwood

Cornus amomum

Silky Dogwood

Group 2 (Acceptable)

Scientific Name

Viburnum recognitum

Arrowwood Vibumum

Cornus racemosa

Gray Dogwood

Alnus rugosa

Speckled Alder

2.

Proportioning: Select plants in the field from Group 1 then from Group 2.

a.

Harvest at least 75% of all plants from Group 1.

b.

Use a minimum of two (2) species from Group 1.

3.

Cut shrubs and young trees directly above the ground. ‘Top’ trees that are greater than 1 and ½-inches in diameter. Cuttings less than 3 feet long and greater than 6 feet long are not acceptable.

4.

Make flat or blunt angle clean cuts and keep cut surface small. The use of loppers or larger pruning shears may be required. Avoid bark stripping or wood splitting.

5.

Packaging:

Tie cuttings into bundles of ten (10) cuttings per bundle.

Length may vary depending on length of species used.

b.

Taper bundles at the ends.

c.

Extend bundle one to two feet longer than the average length of stems to achieve this taper.

d.

Butts of stems greater than 1 and 1/2-inches in diameter are not acceptable.

2.

Tie bundles on 15-inch centers with a minimum of two wraps of binder’s twine or heavier tying materials with a non-slipping knot.

a.

Tying may be done with a strapping machine or other methods that tightly compress the bundles.

b.

Bundles, when compressed firmly and tied, shall be 8-inches in diameter.

3.

Place stems alternately and randomly so that approximately one-half the butt ends are at each end of the bundle and the butts are staggered within the bundle.

4.

Package cuttings in easily handled bundles prior to transporting.

a.

Use wire or rope ties of adequate strength to prevent breakage during handling.

C.

Live Branches

Brush Cultivar:

Live brush for brush layers shall be 3 to 7 feet in length, as shown on the plans, with a basal end of 0.25 to 1 inch in diameter. Each stem shall contain at least two healthy side branches; side branches shall not be trimmed off. All live brush plant materials are subject to inspection and approval by the Contracting Officer.

Quality:

Dormant live brush shall be cut from approved harvesting sites during the dormant season or purchased from a source approved by the Contracting Officer.

3.

Species

Group 1 (Recommended)

Botanical Name

Cornus stolonifera

Red Osier Dogwood

S. exigua

Sandbar Willow

Salix purpurea

Purpleosier Willow ”Streamco”

Salix x cottetii

Dwarf Willow “Bankers”

Group 2 (Acceptable)

Botanical Name

Viburnum acerifolium

Mapleleaf viburnum

Viburnum lentago

Nannyberry viburnum

Viburnum alnifolium

Hobblebush

Viburnum recognitum

Arrowwood viburnum

Cephalanthus occidentais Buttonbush

6.

INSTALLATION

A.

General

Live branches shall be installed from September 1st to December 1st and March 15th to June 1st (unless otherwise specified). Brush layering shall be installed only during periods when beneficial results can be obtained. When drought, excessive moisture, or other unsatisfactory conditions prevail, the work shall be stopped when directed. When special conditions warrant a variance to the brush layering operations proposed alternative times shall be submitted for approval.

B.

In-Situ Soil

It is intended that the in-situ soil material, as defined herein and approved by the Contracting Officer, be obtained from approved on-site excavation operations, and be used in constructing the brush layer bioengineering systems after fertilizer and lime have been mixed with the material. Additional required suitable fill material shall be obtained from sources selected by the Contractor and approved by the Contracting Officer and meet the requirements specified herein.

The in-situ soil material shall be natural, viable soil capable of supporting plant growth. In addition, fertilizer and lime shall be mixed into the material as needed (in accordance with soil tests). The material shall be free of any admixture of subsoil, foreign matter, objects larger than three (3) inches in any dimension, toxic substances, or any material or substance which could be harmful to plant growth. Gravel alone shall not be considered a suitable material for use around live cut plant materials. Muddy (over-saturated) soils, which otherwise meet these requirements, shall not be considered suitable material until they have been dried to a workable moisture content. Heavy clays shall be mixed with sandy and/or organic soils to increase porosity. Acceptability of materials used to prepare the select fill shall be determined on-site by the Contracting Officer.

C.

Installing Brush Layers

1. Brush layers are constructed above the top of channel lining riprap on the slopes of the flood control channel, as indicated on the drawings. Above the top of the channel lining riprap, a trench shall be excavated into the slope, on contour, sloping downward from the face of the bank 10 degrees below horizontal as shown on the drawings. Live branches of willow and other species as listed in this specification, shall be placed in the trench with their basal end pointed inward and no less than 5 inches or more than 18 inches of the tips extending beyond the face of the slope. Brush layers shall be from 3 to 4 feet in length at a density of 10 stems per foot of bank. Branches shall have a basal end of 0.25 to 1 inch in diameter and crisscrossed. Brush layers shall be covered with at least 4 to 5 inches of in-situ soil or topsoil immediately following placement and the material compacted firmly, so as to create good stem to soil contact throughout the brush layer. Other brush layers shall be placed, as needed, on contour intermittently upslope as indicated on the drawings. If cohesionless, disturbed, or fill soil is encountered in between brush layers, it will be necessary to cover that soil with 900 cm./sp. Meter coir fabric. The coir-covered zone in between the brush layers shall be seeded with a native grass seed mix and staked as shown on the drawings. Coir fabric shall be overlapped at all seems a minimum of 12”.

2. Watering shall be started immediately after completing each day of brush layering. Water shall be applied at a rate sufficient to ensure moist soil conditions to a minimum 1 foot depth. Run-off, puddling, and wilting shall be prevented. Unless otherwise directed, watering trucks shall not be driven over turf areas. Watering of other adjacent areas or plant material shall be prevented.

D.

Installing Live Branches

1. Live Branches are an element of the Vegetation Reinforced Soil System constructed above the top of channel lining riprap on the slopes of the flood control channel, as indicated on the drawings. Above the top of the channel lining riprap, a series of 12” soil lifts will be constructed of two 6” compacted soil lifts and completely wrapped in a layer of Coir or Burlap Fabric and then a layer of geogrid. Live branches of shrub willow and other species, as listed in this specification, shall be placed between successive soil lifts with their basal end pointed inward and no less than 8 inches or more than 12 inches of the tips extending beyond the face of the slop. Live Branches shall have a minimum embedment depth of 3 to 7 feet at a density of 10 stems per foot of bank. Branches shall have a basal end of 0.25 to 1 inch in diameter. Coir/burlap fabric shall be overlapped at all seams a minimum of 12”.

2. Watering shall be started immediately after completing each day of Vegetation Reinforced Soil System construction. Water shall be applied at a rate sufficient to ensure moist soil conditions to a minimum 1 foot depth. Run-off, puddling, and wilting shall be prevented. Unless otherwise directed, watering trucks shall not be driven over turf areas. Watering of other adjacent areas or plant material shall be prevented.

E.

Installing Live Stakes

1.

Live stakes for Fascine installation shall be 18”-24” in length with a basal end of 1 to 2 inches diameter. All live stakes are subject to inspection and approval by the Contracting Officer.

Dormant live stakes shall be cut from approved harvesting sites during the dormant season or purchased from a source approved by the Contracting Officer.

3.

Only species of willow shall be used for live stakes for fascine installation.

4.

No more than 25% of live stake shall be left exposed above grade after installation. If bark is split away from cambium layer at terminal end during installation, the top of the live stake shall be freshly cut again with lopping or pruning shears leaving a smooth cut without bark separating from cambium. Live stakes will be inserted into soil in such a manner so that no air pockets will occur between the stake and the surrounding soil.

F.

Installation of Live Fascines

1.

Existing ground above and between Live Fascine rows shall be seeded with an upland seed mix. The upland seed mix shall be covered with straw mulch and then overlaid with 700 gm/s Coir Fabric. The Coir fabric shall be secured by dead stout stakes as shown on the Drawings.

2.

Live stakes shall be used during the installation of the live fascines and shall be in a dormant stage. Live stakes shall be installed at a spacing of no more than 3 feet on center (O-C) in conjunction with stout stakes. No more than 25% of live stake shall be left exposed above grade after installation. If bark is split away from cambium layer at terminal end during installation, the top of the live stake shall be freshly cut again with lopping or pruning shears leaving a smooth cut without bark separating from cambium. Live stakes will be inserted into soil in such a manner so that no air pockets will occur between the stake and the surrounding soil.

3.

Live Fascines shall be covered with topsoil leaving the top 2 to 3 inches slightly exposed. The topsoil shall be worked and tamped firmly so that no air pockets occur between stems in the fascine and the surrounding soil.

4.

Watering shall be started immediately after completing each day of Live Fascine installation. Water shall be applied at a rate sufficient to ensure moist soil conditions. Run-off, puddling, and wilting shall be prevented. Unless otherwise directed, watering trucks shall not be driven over turf areas. Watering of other adjacent areas or plant material shall be prevented.

7.

MAINTENANCE DURING STORAGE

A.

If immediate delivery to the construction site is not possible, maintain cuttings throughout the storage period as specified in Section 3.

B.

Materials in storage may be viewed periodically by the Government. Provide access to the Government when desired.

8.

DELIVERY

A.

Coordinate with the Contracting Officer to ensure that materials are delivered to the job site in a timely manner. Report any practices planned during construction that may prevent establishment of the cuttings.

B.

Deliver as specified in Section 3. Maintain conditions of cuttings throughout transport and delivery. Provide instructions on the proper handling and protection of cuttings prior to installation.

9.

PLANTING

A.

Depth, spacing, and limits of plantings are shown on the Drawings.

1. The geometric pattern of the planting may be interrupted by the presence of mature trees within the planting area.

Resume plant spacing as soon as practicable adjacent to the mature trees.

10.

MAINTENANCE OF PLANTED AREAS

Maintenance operation shall begin immediately after planting and shall continue as required until final acceptance, and for a one-year guaranty period after final acceptance. Plants shall be kept in a healthy, growing condition by watering, pruning, spraying, weeding, mulching and any other necessary operations of maintenance. The Contractor may pump water from the river for watering during construction and the one-year maintenance period.

11.

MEASUREMENT AND PAYMENT

A.

Live Fascines

1.

Measurement will be based on the linear feet of 10-cutting bundles installed in satisfactory condition. Payment for harvesting, delivery, excavation, and installation, select fill, and, if necessary, storage of cuttings will be made at the contract unit price for linear feet of “Live Fascines”.

B.

Live Branches

1.

Measurement will be based on the linear feet of Brush Layer/Live Branch rows installed in satisfactory condition. Payment for harvesting, delivery, installation, and, if necessary, storage of cuttings will be made at the contract unit price for linear feet of “Brush Layers/Live Branches”.

C.

Live Stakes

1.

Measurement will be based on the square feet of Live Stakes installed in satisfactory condition. Payment for harvesting, delivery, installation, and, if necessary, storage of cuttings will be included under the contract unit price for “Live Stakes”.

D.

Dead Stout Stakes

1.

No Measurement will be made for this item. Payment will be included under the contract unit price for “Live Fascines” or “Brush Layers”.

E.

Coir/Burlap Fabric

1.

Measurement will be based on the actual square yards of coir/burlap fabric placed, including overlap, per limits described in specifications and shown on plans. Payment for purchase, delivery, and installation will be made at the contract unit price for square yards of “Coir/Burlap Fabric”

F.

In-Situ Soils

No measurement will be made. Payment will be made at the contract lump sum price for “In-Situ Soils”

12.

ITEMS OF WORK AND CONSTRUCTION DETAILS

The items of work to be performed in conformance with this specification and the construction details are:

A. Bio-Engineering

(1) This item shall consist of the labor and materials necessary to establish the Bio-Engineering techniques as shown on drawings.

(2) The Sponsor shall be responsible for identifying and supplying of the necessary plant materials. Contractor shall coordinate with the Sponsor and give sufficient notification prior to installing materials.

(3) In Section 5, Dormant Live Cuttings, the species to be used shall be Salix purpurea (Purpleosier Willow “Streamco”) and/or Cornus stolonifera (Red Osier Dogwood). Due to the time of year, dormant cutting are not available. Therefore, live cutting shall be used soaked and installed within 48 hours.

(4) In Section 10, Maintenance of Planted Area, the one-year guaranty period shall be the responsibility of the Sponsor not the Contractor.

(5) Live Stakes will be installed above the rock riprap in three rows according to F.2. in Section 6 and as shown on the drawings.

(6) Live Branches shall be installed above the toe rock according to D.1. in Section 6 and as shown on the drawings.

(7) Live Branches shall be installed along the upstream edge of the tiebacks vertically according to D.1. in Section 6 and as shown on the drawings.

(8) Watering of the Bio-Engineering plantings is not required after installation.

(9) Measurement and Payment, The measurement and payment for the necessary labor will not be any of the methods, but will be made as a lump sum price.

PAGE

NY-MORAN AUGUST 2004