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HYDRODYNAMIC CONTROL OF AN EMERGENT AQUATIC PLANT ( SCIRPUS ACUTUS ) IN OPEN CHANNELS 1
Author(s) -
Groeneveld David P.,
French Richard H.
Publication year - 1995
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1995.tb04037.x
Subject(s) - flow (mathematics) , channel (broadcasting) , flow velocity , environmental science , drag , block (permutation group theory) , habit , scirpus , hydrology (agriculture) , biology , ecology , botany , geology , wetland , mechanics , physics , mathematics , geotechnical engineering , engineering , psychology , psychotherapist , geometry , electrical engineering
Control of emergent aquatic plants such as tule ( Scirpus acutus Muhl.; Bigel.) is of direct interest to managers of surface waters in Western North America. Where conditions of water velocity and depth occur that permit this and similar species to colonize and grow, their clonal habit may restrict, or even block, open channels within several seasons after their establishment. Fortunately, sufficient flow depth and velocity naturally prevent these plants from growing into and blocking channels. We investigated physical constraints for tule stem growth with the ultimate intent to apply this knowledge in rehabilitating 60 miles of the diverted Owens River in Eastern California, presently choked with emergent growth. Bending stress resulting from hydrodynamic drag on tule stems was found to induce lodging; permanent deformation and consequent loss of function. The depth‐velocity envelope describing this process (at 95 percent confidence) is uD/d = 12.8 where u = average velocity acting upon the stem (m/s), D = local depth of flow (m), and d = tule stem diameter at the point of attachment (m). Maintaining a discharge or reconfiguring a channel so this critical depth‐velocity‐stem diameter envelope is exceeded (predictable using flow models) through the summer growing period should prevent encroachment into an active channel.