Pools, cannel form, and sediment storage in Wood-restored streams: Potential effects on downstream reservoirs

 

Authors
Molinero Ortiz, Jon
Format
Article
Status
publishedVersion
Description

Large wood (LW, or pieces of dead wood longer than 1 m and thicker than 10 cm in diameter) is a key element in forested streams, but its abundance has decreased worldwide as a result of snagging and clearing of riparian forests. Therefore, many restoration projects introduce LW into stream channels to enhance geomorphology, biotic communities, and ecosystem functioning. Because LW enhances the retention of organic matter and sediments, its restoration can reduce siltation in receiving reservoirs, although so far little information on this subject is available. We studied the effects of restoring the natural loading of LW in four streams in the Aiako Harria Natural Park (the Basque Country, Spain) in pool abundance, channel form, and storage of organic matter and sediments. In all reaches log jams induced the formation of new geomorphic features and changes in physical habitat, especially an increase in the number and size of pools and in the formation of gravel bars and organic deposits. The storage of organic matter increased 5- to 88-fold and streambed level rose 7 ? 4 to 21 ? 4 cm on average, resulting in the storage of 35.2 ? 19.7 to 711 ? 375 m3 (733?1400 m3 ha? 1 y? 1) of sediment per reach. Extrapolation of these results to the entire drainage basin suggests that basinwide restoration of LW loading would enhance the retention potential of stream channels by 66,817 ? 27,804 m3 (1075 m3 ha? 1 y? 1) of sediment and by 361 t (5.32 T ha? 1 y? 1) of organic matter, which represents 60% of the estimated annual inputs of sediments to the downstream A?arbe Reservoir and almost twice as much as the annual input of organic matter to the entire river network. Therefore, basinwide restoration of LW loading is a potentially important tool to manage catchments that feed reservoirs, where retention of sediments and organic matter can be considered important ecosystem services as they reduce reservoir siltation.
http://www.sciencedirect.com/science/article/pii/S0169555X1630006X

Publication Year
2016
Language
eng
Topic
WOOD
CHANNEL ACCRETION
STREAM
RESERVOIR SILTATION
ECOSYSTEM SERVICE
Repository
Repositorio SENESCYT
Get full text
http://repositorio.educacionsuperior.gob.ec/handle/28000/3847
Rights
openAccess
License
restrictedAccess