Accession Number : ADA259103


Title :   Incremental Effects of Large Woody Debris Removal on Physical Aquatic Habitat.


Descriptive Note : Final rept.,


Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB


Personal Author(s) : Smith, Roger H ; Shields Jr, F D ; Gibson, Anthony C ; Schaefer Jr, Thomas E ; Dardeau, Elba A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259103.pdf


Report Date : Nov 1992


Pagination or Media Count : 84


Abstract : Large woody debris (LWD) removal (also called clearing and snagging) is a widely employed practice. The LWD is removed from small channels to increase conveyance (i.e., reducing the stage and duration of high frequency flooding) and from large channels to eliminate navigation hazards. Complete removal of LWD can have detrimental effects upon stream habitats. Thus, a balance between habitat considerations and channel conveyance is necessary. Selective removal of bank and near-channel floodplain vegetation and channel obstructions is a means of accomplishing this balance. The principal objective of this study was to investigate incremental effects of selective clearing and snagging on physical conditions and aquatic habitat in a sand bed river. The study was part of a larger program to develop techniques to quantify and predict incremental physical and biological effects of LWD removal. Long-term research objectives are to relate the densities and types of LWD formations in streams to specific biotic parameters, near-bank-full friction factor, and longitudinal dispersion as an indicator of the tendency a channel reach to trap and hold fine particulate matter. In this study, a simple method for quantifying LWD density and computing associated friction factors was developed and tested using data collected during a clearing and snagging project on the South Fork Obion River in western Tennessee. Physical conditions of both cleared and uncleared stream reaches were measured by collecting three types of data: LWD density, dye tracer tests (for computing reach mean hydraulic parameter), and physical habitat (depth, velocity, bed type, and cover) at selected transects.... Clearing, Dye tests, Large woody debris, Physical aquatic habitat, Snagging, South Fork Obion River.


Descriptors :   *HABITATS , TEST AND EVALUATION , HIGH FREQUENCY , REMOVAL , DEBRIS , SAND , NAVIGATION , HETEROGENEITY , STREAMS , MICROBALANCES , TRAVEL TIME , FRICTION , PARTICULATES , DYES , RIVERS , TENNESSEE , HYDRAULICS , VEGETATION


Subject Categories : Ecology
      Water Pollution and Control


Distribution Statement : APPROVED FOR PUBLIC RELEASE