Potential Responses of Riparian Vegetation to Dam Removal

Shafroth, Patrick B.; Friedman, Jonathan M.; Auble, Gregor T.; Scott, Michael L.; Braatne, Jeffrey H.

doi:10.1641/0006-3568(2002)052[0703:prorvt]2.0.co;2

Cited by 137 publications

(109 citation statements)

References 37 publications

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“…Dams along small-order streams alter (Debano and Schmidt, 1990;Busch et al, 1992;Shafroth et al, 2002) the linkage between headwater and downstream reaches and the level of control that headwater systems exert over downstream reaches (Gomi et al, 2003). Recent studies on impounded headwater streams have shown dams to have a positive influence on downstream riparian vegetation development (Pollard and Reed-Anderson, 2001; Duke et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Riparian influence on hyporheic‐zone formation downstream of a small dam in the Blackland Prairie region of Texas

Duke

White

Allen

et al. 2006

Hydrological Processes

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Abstract:Small-order streams have highly variable flows that can result in large temporal and spatial variation of the hyporheic zone. Dam construction along these intermittent headwater streams alters downstream flow and influences the hydrologic balance between stream water and the adjacent riparian zone. A 3-year site study was conducted along an impounded second-order stream to determine the water balance between stream, unsaturated zone, groundwater and riparian vegetation. The presence of the upstream impoundment provided near-perennial water flow in the stream channel. The observed woody plant transpiration accounted for 71% of average annual water loss in the site. The overall contribution of stream water via the hyporheic zone to site water balance was 73 cm, or 44% of total inputs. This exceeded both rainfall and upland subsurface contribution to the site. A highly dynamic hyporheic zone was indicated by high water use from woody plants that fluctuated seasonally with stream water levels. We found leaf area development in the canopy layer to be closely coupled with stream and groundwater fluctuations, indicating its usefulness as a potential indicator of site water balance for small dam systems. The net result of upstream impoundment increased riparian vegetation productivity by influencing movement of stream water to storage in the groundwater system.

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Section: Introductionmentioning

confidence: 99%

Riparian influence on hyporheic‐zone formation downstream of a small dam in the Blackland Prairie region of Texas

Duke

White

Allen

et al. 2006

Hydrological Processes

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“…In the Carmel River, removal of San Clemente Dam is expected to benefit the imperiled red-legged frog Rana draytonii (CDWR 2012). Native riparian vegetation may also benefit from dam removal (Poff et al 1997), although benefits may only manifest after long periods and in absence of invasive non-native plants (reviewed in Shafroth et al 2002). River ecosystems overall are expected to become more resilient upon dam removal if they are not so altered as to inhibit restoration of natural conditions (e.g., Hamilton et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Dam removal and anadromous salmonid (Oncorhynchus spp.) conservation in California

Quiñones

Grantham

Harvey³

et al. 2014

Rev Fish Biol Fisheries

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Dam removal is often proposed for restoration of anadromous salmonid populations, which are in serious decline in California. However, the benefits of dam removal vary due to differences in affected populations and potential for environmental impacts. Here, we develop an assessment method to examine the relationship between dam removal and salmonid conservation, focusing on dams that act as complete migration barriers. Specifically, we (1) review the effects of dams on anadromous salmonids, (2) describe factors specific to dam removal in California, (3) propose a method to evaluate dam removal effects on salmonids, (4) apply this method to evaluate 24 dams, and (5) discuss potential effects of removing four dams on the Klamath River. Our flexible rating system can rapidly assess the likely effects of dam removal, as a first step in the prioritization of multiple dam removals. We rated eight dams proposed for removal and compared them with another 16 dams, which are not candidates for removal. Twelve of the 24 dams evaluated had scores that indicated at least a moderate benefit to salmonids following removal. In particular, scores indicated that removal of the four dams on the Klamath River is warranted for salmonid conservation. Ultimately, all dams will be abandoned, removed, or rebuilt even if the timespan is hundreds of years. Thus, periodic evaluation of the environmental benefits of dam removal is needed using criteria such as those presented in this paper.

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“…Removal of a dam exposes a large area of reservoir sediment that is highly conducive to plant colonization, especially of invasive species. Aggressive plant colonists may dominate for several years if natives fail to survive because of strong competition (D'Antonio and Meyerson 2002, Shafroth et al 2002, Orr and Stanley 2006. Connectivity is often lost in aquatic ecosystems because of dam construction.…”

Section: Cultural-historical Obstaclesmentioning

confidence: 99%