Vegetation (Floating River Vegetation) - Office of Public Works

Vegetation (Floating River Vegetation) - Office of Public Works Vegetation (Floating River Vegetation) - Office of Public Works

20.03.2013 Views

Absence of floating river vegetation during summer months due to excess shading River Breagagh Winter 2006 River Breagagh Summer 2006 Corresponding points in summer and winter 50

River Breagagh Winter 2006 Ranunclion growth during summer not affecting winter water flow Corresponding points in summer and winter Fig. 10 Effect of floating river vegetation growth on winter water flow on the River Breagagh (Site 5) survey site. Water crowfoot adjacent to the weir does not appear to interfere with winter flow. Further upstream the eroded riverbank that supported water parsnip is totally submerged. Its location is illustrated by a series of vortices evident on the water surface. An alternative situation is occurring on the bend of the river, the area supporting the water crowfoot during the summer months is depicted as an area of minimal energy flow. Whether the vegetation has adapted to a section on the river where the flow has differed due to some environmental dynamic or that the vegetation has exerted a regime on the water flow is not entirely clear. It is likely that a difference in flow dynamic has enabled the colonisation of floating river vegetation and consequently the presence of the plant growth is facilitating further change in the surrounding environment (Fig. 10) which, if unmaintained would result in silt build-up and replacement by different plant species over time. In 51

<strong>River</strong> Breagagh<br />

Winter 2006<br />

Ranunclion growth during summer not affecting winter water flow<br />

Corresponding points in summer and winter<br />

Fig. 10 Effect <strong>of</strong> floating river vegetation growth on winter water flow on the <strong>River</strong><br />

Breagagh (Site 5) survey site.<br />

Water crowfoot adjacent to the weir does not appear to interfere with winter flow. Further<br />

upstream the eroded riverbank that supported water parsnip is totally submerged. Its location is<br />

illustrated by a series <strong>of</strong> vortices evident on the water surface. An alternative situation is occurring<br />

on the bend <strong>of</strong> the river, the area supporting the water crowfoot during the summer months is<br />

depicted as an area <strong>of</strong> minimal energy flow. Whether the vegetation has adapted to a section on the<br />

river where the flow has differed due to some environmental dynamic or that the vegetation has<br />

exerted a regime on the water flow is not entirely clear. It is likely that a difference in flow dynamic<br />

has enabled the colonisation <strong>of</strong> floating river vegetation and consequently the presence <strong>of</strong> the plant<br />

growth is facilitating further change in the surrounding environment (Fig. 10) which, if<br />

unmaintained would result in silt build-up and replacement by different plant species over time. In<br />

51

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