Usda Natural Resources Conservation Service s1

USDA NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE SPECIFICATION ARIZONA IRRIGATION WATER CONVEYANCE DITCH AND CANAL LINING FLEXIBLE MEMBRANE (acre) CODE NO. 428B

1. SCOPE film, care shall be taken to insure that at least 5 percent slack is The work shall consist of all provided. Prefabricated asphalt preparation, earthfill, excavation and membranes shall be pulled out so furnishing and placing lining. that they lay flat on the subgrade. required for construction of the ditch and canal lining. If the width or length of the lining specified requires placing sheets 2. SPECIAL REQUIREMENTS together, all joints shall be watertight, and the strength of the Installation shall be in accordance with bonded seam in any direction shall the following drawings, specifications not be less than 80 percent of and special requirements. NO breaking strength (ultimate tensile CHANGES ARE TO BE MADE IN THE strength) of the membrane when DRAWINGS OR SPECIFICATIONS the specimen is pulled in shear. WITHOUT PRIOR APPROVAL OF NRCS. c. Anchoring Membranes

Other Requirements Small anchor trenches about 10 in. wide and 12 in. deep shall be used to anchor the sides of the mem- 3. INSTALLATION brane. These trenches shall be A. Preparing Subgrades located along the berm on both sides of the canal. They shall be a Subgrades on which flexible minimum of 4 in. back on the berm membranes will be placed shall from the top of the side slope and at be raked to remove all large the elevation required to maintain clods, roots, brush, sod, or rocks the specified freeboard. The that might endanger the membrane shall conform to the membrane. Rolling the subgrade trench shape and shall extend a is recommended to provide an minimum of 8 in. up the side extra measure of safety against opposite the canal. The trenches punctures. In rocky areas, a shall be carefully backfilled and cushion layer of fine soil shall be compacted after the membrane is in provided as a protection against place. irregularities that cannot be removed by rolling. The upstream end of each section of plastic or rubber membrane shall B. Placing Membranes be anchored in a trench dug across the canal. This trench shall be about Plastic and rubber membranes 10 in. wide and 12 in. deep and shall be carefully spread in a shall connect with the two side relaxed condition over the raked anchor trenches. The upstream end and smoothed subgrade. Rubber of the membrane section shall lap sheets may be pulled out smooth, down a minimum of 12 in. into this but all liners shall be installed in a transverse trench. After the relaxed state. For polyethylene

NRCS Field Office Technical Guide, Section IV Page 1 of 5 NRCS, Arizona July, 1980 membrane is in place, the trench their serviceability. They shall be shall be carefully backfilled with packaged so as to prevent damage from selected compacted material. rough handling during shipment and so as to facilitate placement at the job site. Prefabricated asphalt membranes Each package shall be marked with the shall be anchored at the upstream name of the material, the manufacturer's end of the lining section and at such name or symbol, the quantity contained intermediate points as are specified therein, and the thickness or unit for individual jobs. weight of the material.

No anchors shall be required at the Flexible membrane liners of the downstream end of membrane materials shown shall equal or sections. The downstream end of exceed the physical requirements the membrane shall be lapped a listed in table 1 (Polyethylene and minimum of 3 ft. over the anchored ethylene co-polymer plastic film); upstream end of the next section. table 2 (Reinforced rubber sheeting); Placement of the protective cover and table 3 (Unreinforced rubber material will secure the joint. sheeting). Polyvinyl chloride plastic sheeting shall meet the requirements d. Placing Protective Cover indicated in ASTM-D-3083. Material to be used as protective cover on membrane linings shall 7. REQUIRED ATTACHMENTS be free of large clods and sharp Plan Map showing location rocks and shall be carefully placed to the specified depth without Designs showing alignment, width, damaging the membrane. side slopes, drainage, erosion control, surfacing, traffic safety, and construction e. Construction Operations operations. Drawings, No. Construction operations shall be done in such a manner that erosion and air and water pollution are 8. OTHER ATTACHMENTS minimized and held within legal Associated Practice Specifications limits. The completed job shall be workmanlike and present a good Water Quality Considerations appearance. Other 6. MATERIALS

The flexible sheets or films to be used 9. OPERATION AND as buried membrane linings in irrigation MAINTENANCE ditches or canals shall be suitably This conservation practice is an asset to constructed of high-quality ingredients your farm or ranch. This practice will and shall be certified by the manu- need periodic operation and facturer to be suitable for this intended maintenance to maintain satisfactory use. Pigmented polyvinyl or poly- performance. The life of this practice or ethylene plastic, rubber, asphalt, or system is at least 10 years. The life of similar materials that are highly this practice can be assured or resistant to bacteriological deterioration extended by thorough and timely shall be acceptable base materials for operation and maintenance. Here are buried membrane linings. some recommendations to help you develop a good operation and The fabricated membranes shall be maintenance program. uniform throughout and shall be free from dirt, oil, foreign matter, pits, tears, holes, or other defects that can affect

NRCS Field Office Technical Guide, Section IV Page 2 of 5 NRCS, Arizona July, 1980 GENERAL RECOMMENDATIONS Remove debris to prevent blockage of stream crossings, culverts or Maintain the roadway surface in a bridges. good condition, which includes periodic grading or repair of the Control all rodents or burrowing surface. animals. Immediately repair any damage caused by their activity. Prevent surface ponding by grading to remove depressions. Immediately repair any damage from vandalism, vehicles, or livestock. Limit livestock usage to periods that permit use without damage. Specific Recommendations For Your If fences are installed, they shall be Installation maintained to provide warning and/or prevent unauthorized human or livestock entry.

TABLE 1 – Requirements for polyethylene and ethylene co-polymer plastic film Requirements Test Description Type I Type II Test Method Poly- Co- ethylene polymer Tensile strength each direction, Lb/in2 1800 2000 ASTM-D-882 minimum, average Method “A” Ultimate elongation each direction, Pct 500 500 ASTM-D-882 minimum, average Method “A” Impact resistance, minimum average g/mil 45 65 ASTM-D-1709 Method “A” Water vapor permeability Perm- 0.7 1.5 ASTM-E-96 mil Tear resistance (Elmendorf) each g/mil 80 80 ASTM-D-1922 direction, minimum Soil burial, tensile retained, each Pct 95 95 ASTM-D-3083 direction, minimum Soil burial, elongation retained, each Pct 80 80 direction, minimum Luminous transmittance, maximum Pct 1.0 1.0 National Bureau of Standards Publication PS- 17

NRCS Field Office Technical Guide, Section IV Page 3 of 5 NRCS, Arizona July, 1980 TABLE 2 – Requirements for reinforced rubber sheeting Requirements Test Description As 20 mils Test Method much as thick and 20 mils greater thick Breaking strength, minimum ASTM-D-751 wrap direction Lb/in 75 100 Fill direction Lb/in 75 100 Ultimate elongation, minimum, ASTM-D-751 wrap direction Pct 30 30 Fill direction Pct 30 30 Ozone resistance, procedure “B” ASTM-D-1149 50 pphm, 100° F Days 7 7 ASTM-D-518 Hydrostatic strength retained after ozone Federal exposure, 7 days (Mullen) Specification CCC-T-19 lb, Method 5512 Pct 100 100 ASTM-D-518 Heat aging, 7 days at 212° F ASTM-D-573 Tensile strength retained Pct 90 90 Elongation retained Pct 90 90 Tear resistance, minimum warp or fill Lb 8 8 ASTM-D-751 direction (tongue) Hydrostatic burst (Mullen), minimum lb/in2 100 175 ASTM-D-751 Dimensional stability, 7 days at 212° F, Pct ±1.0 ±1.0 1 change in length or width Low temperature flexibility (optional), no Pct -40° F -40° F Federal cracking or flaking specification CC- T-19 lb, Method 5874 Commercial field splice strength, shear Pct 75 75 Commercial field force, minimum tensile splice 1-in wide strip, pulled in shear at 10 in/min., after 7 days cure at room temperature.

1 A 1 ft sample, 10-in bench marks in warp and fill direction, placed on aluminum or stainless plate in changing weir over.

NRCS Field Office Technical Guide, Section IV Page 4 of 5 NRCS, Arizona July, 1980 TABLE 3 – Requirements for un-reinforced rubber sheeting Requirements Test Description Type A Type B Test Method Tensile strength, minimum Lb/in2 1200 1200 ASTM-D-412 Modulus at 300% elongation , minimum Lb/in2 600 600 ASTM-D-412 Ultimate elongation, minimum Pct 300 300 ASTM-D-412 Shore “A” hardness 60±10 60±10 ASTM-D-2240 Ozone resistance, procedure “A” ASTM-D-1149 No cracks, 50 pphm at 100°F, 20% elongation Days 7 7 ASTM-D-518 No cracks, 100 pphm at 100°F, 50% elongation Days - 7 ASTM-D-518 Heat aging, 7 days at 212° F ASTM-D-573 Tensile strength retained Pct 75 75 Elongation retained Pct 75 75 Water vapor permeability at 80° F Perm 0.002 0.05 ASTM-D-96 mil (procedure BW) Tear resistance, minimum Lb/in2 150 150 ASTM-D-624 Die “B” Dimensional stability, 7 days at 212° F, Pct ±0.5 ±0.5 change in length or width Commercial field splice strength, shear Pct 65 65 Commercial field force, minimum tensile splice 1-in wide strip, pulled in shear at 10 in/min., after 7 days cure at room temperature. NOTE: Type A sheeting is recommended for general-purpose outdoor use. Tyep B sheeting is suggested if an extreme outdoor environment makes a highly wearable lining necessary.

NRCS Field Office Technical Guide, Section IV Page 5 of 5 NRCS, Arizona July, 1980