Twenty Years of “Plug-and-Pond” Meadow Restoration: A Geomorphic Review

Abstract:

Channel incision has degraded the ecological function of wet meadows across montane regions of California. Conservation groups estimate that half of the Sierra Nevada’s 333,000 acres of meadow are entrenched in a degraded state that is characterized by a shift from groundwater­fed, herbaceous vegetation to more sparse, drought­tolerant woody vegetation.

My poster will present results of field research on a prominent restoration technique in California's montane meadows, the "Plug­and­Pond." Fundamentally, the technique re­channelizes the meadow by blocking flow into incised stream channels. Spoils dug from meadow sediments plug the incised channel, creating ponds as a by­product. One of three approaches to re­channelization ensues: (1) construct a new shallow and sinuous channel, (2) redirect flows into a remnant channel, (3) or allow the channel to define itself over the meadow floodplain. Re­ channelization aims to support overbank flows at 1.5 to 3 year recurrence intervals.

Field surveys of ten of the oldest “plug-and-pond” meadow restoration projects in California reveal that channel bed degradation caused by meadow-scale changes to channel slope (i.e. culverts concentrating flows, channel straightening, meadow grazing) may be more conducive to intensive restoration approaches like Plug-and-Pond.