Notes

INTRO CONT.
Many lowland streams have been extensively altered by channelization, and channel restoration to rehabilitate dam- aged or degraded reaches of these streams
Channel restoration projects are used to stabilize channels, control bank erosion, and enhance the quality of aquatic habitat by modifying instream structures

Frequently used methods are the placement of boulders, the construction of deflectors and riffles, and channel remeandering at a larger scale

reinstatement of relatively coarse substrates that do not erode during bankfull flow (flooding) events is also a common practice. The coarse substrate may enhance stream-subsurface water exchange and, in turn, the transfer of dissolved solutes from the stream to the stream bed is also enhanced
this is usually done to improve habitat structure, but it also enhances HZ exchange...we can use river restoration to help us better understand the HZ

Natural riffle-pool and step-pool sequences have received most attention among the range of channel morphological features that exert a strong control on hyporheic exchange

The objectives of the research were to examine (i) the stream-subsurface water interaction induced by constructed riffles and steps and (ii) the patterns of subsurface chemistry with particular focus on oxygen and nitrate dynamics in the hyporheic zone.
hypothesize that constructed riffles and steps enhance hyporheic exchange and expand the zone of increased oxygen and nitrate concentrations in the streambed

method: Our approach involved a comparison of the hyporheic zone beneath a large constructed riffle and a natural riffle at one study site
and analysis of a small constructed riffle and step in two other streams.

Hydrometric data collected from piezometer (test pressure ??) nests and conservative tracer releases were combined to examine stream-subsurface exchanges and reactive element dynamics.