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Providing evidence to improve practice

Individual study: The use of hydrologic and ecological indicators for the restoration of drainage ditches and water diversions in a mountain fen, Cascade Range, California

Published source details

Patterson L. & Cooper D.J. (2007) The use of hydrologic and ecological indicators for the restoration of drainage ditches and water diversions in a mountain fen, Cascade Range, California. Wetlands, 27, 290-304


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Maintain/restore water flow across service corridors Peatland Conservation

A before-and-after study in 2002–2004 in a degraded fen in California, USA (Patterson & Cooper 2007) found that after water flow was restored across a road (along with general rewetting), cover of peatland-characteristic sedges increased whilst cover of grass species preferring drier conditions typically decreased. Cover of three sedge species characteristic of wet peatlands increased (two significantly or marginally so), from 12–15% before rewetting to 13–20% one year after. Cover of three grass species that prefer drier conditions decreased (two significantly), from 2–6% before rewetting to 1–5% one year after. In July 2003, 21 channels were created across a road that blocked surface water flow into the fen. At the same time, the main drainage ditch of the fen was dammed. The study does not distinguish between the effects of these interventions. Vegetation cover was estimated in July before (2002) and after (2004) intervention, in fifty-nine 10 m2 plots.

(Summarised by Nigel Taylor)

Rewet peatland (raise water table) Peatland Conservation

A before-and-after study in 2002–2004 in a degraded fen in California, USA (Patterson & Cooper 2007) found that following rewetting, cover of peatland-characteristic sedges increased whilst cover of grass species preferring drier conditions decreased. Cover of three sedge species characteristic of wet peatlands increased (two significantly or marginally so), from 12–15% before rewetting to 13–20% one year after. Cover of three grass species that prefer drier conditions decreased (two significantly), from 2–6% before rewetting to 1–5% one year after. In July 2003, a fen was rewetted by blocking the main drainage ditch with metal dams. At the same time, channels were dug across a road that previously blocked surface water inflow. The water table was raised, ranging from 55 cm below the peat surface to 15 cm above during the summer. Vegetation cover was estimated in July before (2002) and after (2004) rewetting, in fifty-nine 10 m2 plots.

(Summarised by Nigel Taylor)