Modeling the effects of lowland stream restoration projects on stream-subsurface water exchange

Tamao Kasahara, Alan R. Hill

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

The relative effect of individual elements of restoration projects on stream-subsurface water exchange was studied by identifying elements that were most effective in increasing downwelling stream water (DSW) into subsurface environments using groundwater flow modeling. Several restoration projects studied in lowland streams involved riffle-pool construction, lateral gravel bar construction and channel re-meandering. Simulations using a homogeneous field of mean hydraulic conductivity that removed heterogeneity showed a large decline in DSW in the four restoration projects studied, suggesting that use of coarse sediments in construction initially increases stream-subsurface water exchange, but the effects may not persist in streams where fine sediments clog streambeds. In two riffle-pool construction projects studied, modification of the channel gradient showed a greater effect on DSW than the alteration of substrate texture. In the gravel bar construction site, modeling results indicated that the construction of a riffle-pool sequence along the bar had a greater effect than the construction of the gravel bar itself. In contrast in the channel re-meandering site, the combination of a greater sinuosity and a lower hydraulic head along the small riffles resulted in re-meandering having a greater effect than the associated riffle-pool construction. A simulation in which the floodplain sediments of low saturated hydraulic conductivity at the re-meandered site were replaced with sandy gravels increased DSW by 10 times. This modeling suggests that the addition of coarse sediments in combination with re-meandering would be required to significantly enhance stream-subsurface water exchange in reaches with fine-grained floodplain sediments. Designing the size and type of morphologic features constructed in restoration projects is somewhat flexible, and the use of modeling to simulate stream-groundwater interactions may help to enhance the hydrologic link with a stream and the subsurface environment in restored stream reaches.

Original languageEnglish
Pages (from-to)310-319
Number of pages10
JournalEcological Engineering
Volume32
Issue number4
DOIs
Publication statusPublished - Apr 1 2008
Externally publishedYes

Fingerprint

water exchange
Restoration
Gravel
Sediments
modeling
Water
riffle
downwelling
gravel
Hydraulic conductivity
sediment
Groundwater flow
restoration
effect
project
floodplain
hydraulic conductivity
pool-riffle sequence
Groundwater
water

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Nature and Landscape Conservation
  • Management, Monitoring, Policy and Law

Cite this

Modeling the effects of lowland stream restoration projects on stream-subsurface water exchange. / Kasahara, Tamao; Hill, Alan R.

In: Ecological Engineering, Vol. 32, No. 4, 01.04.2008, p. 310-319.

Research output: Contribution to journalArticle

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