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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

AERIAL SEEDING OF HIGHWAY SLOPES

TWO AREAS WERE SEEDED. HOOSKANADEN CREEK, LOCATED ON NEW COAST HIGHWAY CONSTRUCTION NORTH OF BROOKINGS, COMPRISED A 200-ACRE SLIDE AREA WHICH HAS BEEN CLEARED AND REGRADED TO DRAIN ALL SURFACE WATERS FROM THE SLIDE AREA. THE SECOND, MYRTLE CREEK ON NEW PACIFIC HIGHWAY CONSTRUCTION, IS ABOUT 15 ACRES IN EXTENT. IT IS A BENCHED SECTION WITH MINIMUM 1-TO-1 GRADIENTS IN CUTS UP TO 250 FT IN SLOPE DISTANCE, FURTHER ENLARGED TO TWICE THIS DISTANCE BY A SLIDE IN ONE SECTION. BECAUSE OF THE INACCESSIBILITY OF THE SLIDE AREA TO TRUCKS AND HYDRAULIC SEEDING EQUIPMENT AND THE DANGER AND DIFFICULTY OF WORKING MEN ON THE HIGH, STEEP SLOPES AT MYRTLE CREEK, IT WAS DECIDED TO TRY SEEDING AND FERTILIZING BY HELICOPTER. THE CONTRACTOR USED A LIGHT 3-PASSENGER HILLER HELICOPTER WITH A SINGLE ROTOR AND CAPABLE OF CARRYING A MAXIMUM LOAD OF 300 LB. IT WAS TOWED BY TRUCK AND TRAILER TO THE JOB SITES. FLYING AT AN INDICATED AIR SPEED OF 40 MPH AT A 50-FT ELEVATION, THE AIR RAM FORMED BY THE FORWARD MOVEMENTS OF THE HELICOPTER AND THE DOWNBLAST OF THE ROTOR DISTRIBUTED THE SEED EVENLY IN APPROXIMATELY A 40-FT SWATH. A 10-15-0 LIQUID FERTILIZER FORMULATION WEIGHING 10.3 LB PER GALLON WAS HAULED TO THE SITES IN A TANK DIRECTLY FROM THE DEALER. THE LIQUID WAS DISTRIBUTED FROM TWO BARRELS HOLDING A MAXIMUM OF 30 GAL EACH, MOUNTED ON BOTH SIDES OF THE HELICOPTER. A 26-FT SPRAY BOOM ATTACHED UNDERNEATH THE HELICOPTER WAS EQUIPPED WITH 26 NOZZLES CAPABLE OF DISCHARGING 10 GAL PER MIN AT 20-LB PRESSURE. A LIQUID FERTILIZER WAS USED TO OBTAIN A MORE EVEN DISTRIBUTION AND, AS IT WOULD BE ABSORBED INTO THE SOIL IMMEDIATELY, IT WOULD BE READILY AVAILABLE TO THE NEW SEEDLINGS. THE COST OF LIQUID AND DRY FERTILIZERS IS COMPARABLE. THE HELICOPTER AVERAGED ABOUT 15 TRIPS PER HR AND, BASED ON WRIGHT, SEEDED APPROXIMATELY 8 ACRES PER LOAD AND FERTILIZED 1 1/4 ACRES PER LOAD. TO MINIMIZE THE POSSIBILITY OF MISSING IN THE STRIP METHOD EMPLOYED, THE AREAS WERE SEEDED AND FERTILIZED IN TWO DIRECTIONS WHERE POSSIBLE. THE AVERAGE PER ACRE COST OF THE HOOSKANADEN CREEK PROJECT WAS $51.56 AND THE MYRTLE CREEK JOB AVERAGED $65.48 PER ACRE. THE PRIMARY LIMITING FACTOR TO THIS TYPE OF SEEDING SEEMS TO BE WIND. THE DRIFT WAS EXCESSIVE WHEN WIND VELOCITIES EXCEEDED 10 MPH AND IT WAS NECESSARY TO CEASE OPERATIONS. THE 200-ACRE HOOSKANADEN PROJECT WAS COMPLETED IN 30 HR, NOT MORE THAN 15 HR OF WHICH WAS ACTUAL SEEDING AND FERTILIZING TIME. THE DIFFERENCE WAS LOST TIME DUE EITHER TO THE WIND, TO REST PERIODS FOR THE HELICOPTER OPERATOR AND TO SERVICING OR CHANGING THE EQUIPMENT OF THE MACHINE. BASED ON THIS OPERATION IT IS BELIEVED THAT SEEDING BY HELICOPTER ON HIGHWAY CUT AND FILL SLOPES IS PRACTICAL AND WILL PROVE TO BE A SATISFACTORY METHOD OF OBTAINING A COVER ON CUT AND FILL SLOPES UNDER ADVERSE CONDITIONS, EITHER OF EXTREME HEIGHT AND SLOPE GRADIENT, OR FOR LOCATIONS INACCESSIBLE TO CONVENTIONAL EQUIPMENT. THE DISTRIBUTION OF SEED AND FERTILIZER WAS UNIFORM AND A SATISFACTORY GERMINATION HAS BEEN OBTAINED UNDER THE ADVERSE GROWING CONDITIONS EXISTING AT THESE TWO SITES. /AUTHOR/

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  • Supplemental Notes:
    • pp 35-38, 4 PHOT. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
  • Authors:
    • Astrup, M H
  • Publication Date: 1959

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  • Accession Number: 00205123
  • Record Type: Publication
  • Report/Paper Numbers: pp 27-29
  • Files: TRIS, TRB
  • Created Date: Nov 29 1971 12:00AM