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How wide is a road? The association of roads and mass‐wasting in a forested montane environment
Author(s) -
Larsen Matthew C.,
Parks John E.
Publication year - 1997
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/(sici)1096-9837(199709)22:9<835::aid-esp782>3.0.co;2-c
Subject(s) - mass wasting , landslide , disturbance (geology) , terrain , montane ecology , physical geography , hydrology (agriculture) , elevation (ballistics) , mass movement , rockfall , geology , environmental science , geography , geomorphology , cartography , geotechnical engineering , ecology , geometry , mathematics , biology
A spatial data base of 1609 landslides was analysed using a geographic information system to determine landslide frequency in relation to highways. A 126 km long transportation network in a 201 km 2 area of humid‐tropical, mountainous, forested terrain in Puerto Rico was used in conjunction with a series of 20 buffer (disturbance) zones varying from 5 to 400 m in length, measured perpendicular to the highways. Average landslide frequency in the study area at distances greater than 85 m from roads was about six landslides per square kilometre. At distances of 85 m or less on either side of a highway, landslide frequency was about 30 landslides per square kilometre. On average, this elevated disturbance rate affected 330 m 2 km −2 a −1 within the 170 m swath. The mass‐wasting rate outside of the disturbance zone affected 40 m 2 km −2 a −1 . These results indicate that the rate of mass‐wasting disturbance is increased from five to eight times in a 170 m wide swath along road corridors. The lateral extent of the environmental impact of roads in the study area is greater than is commonly perceived. The approach described herein demonstrates a simple method to assess the spatial association of mass‐wasting with highways. © 1997 by John Wiley & Sons, Ltd.