SEDIMENT PRODUCTION FORM FOREST ROADS IN QUEEN CHARLOTTE FOREST AND POTENTIAL IMPACT ON MARINE WATER-QUALITY, MARLBOROUGH SOUNDS, NEW-ZEALAND

被引：43
作者：
FAHEY, BD
COKER, RJ
机构：
[1] Forest and Wildlands Ecosystem Division, Forest Research Institute, Christchurch
来源：
NEW ZEALAND JOURNAL OF MARINE AND FRESHWATER RESEARCH | 1992年 / 26卷 / 02期
关键词：
Erosion; Forest roads; Marlborough Sounds; Sediment yield;
D O I：
10.1080/00288330.1992.9516514
中图分类号：
S9 [水产、渔业];
学科分类号：
0908 ;
摘要：
Coarse and fine sediment production from surface erosion was measured at three sites on roads formed in weathered schist in Queen Charlotte Forest, eastern Marlborough Sounds, over periods ranging from 2 to 3 years. Two 25 x 4 m run-off plots on freshly graded sections of forest road (gradient 5-degrees) at 460 m elevation yielded annual averages of 0.48 and 0.46 kg m-2, respectively, for coarse sediment production from the road surface and drainage ditch. The cutbank contribution was negligible. Two 5 x 2 m plots established on fresh sidecast fill (gradient 38-degrees) below a newly constructed road yielded an average of 7 kg m-2 yr-1. Sidecast fill with partial vegetation cover (average 50%) contributed c. 3 kg m-2. Fine sediment production measured on a section of road in strongly weathered schist at 70 m elevation was estimated at 2.3 kg m-2 yr-1. Extrapolation of the results to the 39 km of forest road and the 21 km of access tracks and firebreaks suggests that about 2000 t of material is being removed by surface erosion each year (62 t km-2 of forest). This could increase to 7000 t of 218 t km-2 yf-1 at the time of harvesting. Log landings could add a further 20%. Background fates of erosion are in the range 300-600 tkm-2 yr-1. Up to 200 t of fine sediment may enter local embayments annually which could cause suspended sediment concentration in sea water to rise temporarily to 1000 mg l-1.
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页码：187 / 195
页数：9
相关论文
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