2010
O’Connor, Ben L.; Hondzo, Miki; Harvey, Judson W.
Predictive Modeling of Transient Storage and Nutrient Uptake: Implications for Stream Restoration Journal Article
In: Journal of Hydraulic Engineering, vol. 136, pp. 1018-1032, 2010.
Abstract | Links | BibTeX | Tags: Fluvial Hydraulics, Nutrient loads, restoration, Surface waters, Transport phenomena
@article{O’Connor2010,
title = {Predictive Modeling of Transient Storage and Nutrient Uptake: Implications for Stream Restoration},
author = {Ben L. O’Connor and Miki Hondzo and Judson W. Harvey},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/OConnor_2010_JoHydrEngineer.pdf},
doi = {10.1061/ASCEHY.1943-7900.0000180},
year = {2010},
date = {2010-01-01},
journal = {Journal of Hydraulic Engineering},
volume = {136},
pages = {1018-1032},
abstract = {This study examined two key aspects of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling and transient storage models for quantifying reach-scale nutrient uptake, and the ability to quantify transport parameters using measurements and scaling techniques in order to improve upon traditional conservative tracer fitting methods. Nitrate (NO−3)(NO3−) uptake rates inferred using the nutrient spiraling model underestimated the total NO−3NO3− mass loss by 82%, which was attributed to the exclusion of dispersion and transient storage. The transient storage model was more accurate with respect to the NO−3NO3− mass loss (±20%) and also demonstrated that uptake in the main channel was more significant than in storage zones. Conservative tracer fitting was unable to produce transport parameter estimates for a riffle-pool transition of the study reach, while forward modeling of solute transport using measured/scaled transport parameters matched conservative tracer breakthrough curves for all reaches. Additionally, solute exchange between the main channel and embayment surface storage zones was quantified using first-order theory. These results demonstrate that it is vital to account for transient storage in quantifying nutrient uptake, and the continued development of measurement/scaling techniques is needed for reactive transport modeling of streams with complex hydraulic and geomorphic conditions.},
keywords = {Fluvial Hydraulics, Nutrient loads, restoration, Surface waters, Transport phenomena},
pubstate = {published},
tppubtype = {article}
}
This study examined two key aspects of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling and transient storage models for quantifying reach-scale nutrient uptake, and the ability to quantify transport parameters using measurements and scaling techniques in order to improve upon traditional conservative tracer fitting methods. Nitrate (NO−3)(NO3−) uptake rates inferred using the nutrient spiraling model underestimated the total NO−3NO3− mass loss by 82%, which was attributed to the exclusion of dispersion and transient storage. The transient storage model was more accurate with respect to the NO−3NO3− mass loss (±20%) and also demonstrated that uptake in the main channel was more significant than in storage zones. Conservative tracer fitting was unable to produce transport parameter estimates for a riffle-pool transition of the study reach, while forward modeling of solute transport using measured/scaled transport parameters matched conservative tracer breakthrough curves for all reaches. Additionally, solute exchange between the main channel and embayment surface storage zones was quantified using first-order theory. These results demonstrate that it is vital to account for transient storage in quantifying nutrient uptake, and the continued development of measurement/scaling techniques is needed for reactive transport modeling of streams with complex hydraulic and geomorphic conditions.
2004
Kotanen, Peter M.
Revegetation following Soil Disturbance and Invasion in a Californian Meadow: a 10-year History of Recovery Journal Article
In: Biological Invasions, vol. 6, no. 2, pp. 245–254, 2004, ISSN: 1573-1464.
Abstract | Links | BibTeX | Tags: aliens, disturbance, exotics, feral pigs, grasslands, invasions, restoration, succession
@article{Kotanen2004,
title = {Revegetation following Soil Disturbance and Invasion in a Californian Meadow: a 10-year History of Recovery},
author = {Peter M. Kotanen},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Revegetation-following-Soil-Disturbance-and-Invasion-in-a-Californian-Meadow-a-10-year-History-of-Recovery-Biological-Invasions_Kotanen1.pdf},
doi = {10.1023/B:BINV.0000022145.03215.4f},
issn = {1573-1464},
year = {2004},
date = {2004-00-00},
journal = {Biological Invasions},
volume = {6},
number = {2},
pages = {245–254},
abstract = {Disturbance is necessary for the regeneration of many native plant species, but can also facilitate biological invasions. As a result, disturbance can play complex roles in vulnerable habitats such as remnant Californian perennial grasslands. To investigate these conflicts, plots in a northern Californian coastal grassland were experimentally disturbed in the winter of 1990-1991; these plots differed in the area and intensity (depth) of the soil disturbance applied. When these plots were revisited after 10 growing seasons, patterns of revegetation differed significantly from those observed early in recolonization (0-3 years). At the earlier samplings, exotic annual grasses rapidly increased in most disturbance types. After 10 years, these exotic annuals had retreated from the depth experiment, which had recovered to a vegetation dominated by native perennials in all but the most severely disturbed plots. In contrast, although differences between control and disturbed plots also disappeared in the area experiment, the average abundance of aliens did not decline substantially relative to 1993 levels, especially in larger disturbances. Nonetheless, populations of aliens remained small compared to the peak populations in the depth experiment, probably reflecting wetter soils at the site used for the area experiment. These results differ from those of other recent studies of soil disturbance in coastal Californian ecosystems, which indicate disturbance may result in the permanent replacement of native perennial vegetation by dense populations of exotic annual grasses. This difference may reflect the high resilience of northern coastal grasslands as well as the scale of disturbances considered by different studies.},
keywords = {aliens, disturbance, exotics, feral pigs, grasslands, invasions, restoration, succession},
pubstate = {published},
tppubtype = {article}
}
Disturbance is necessary for the regeneration of many native plant species, but can also facilitate biological invasions. As a result, disturbance can play complex roles in vulnerable habitats such as remnant Californian perennial grasslands. To investigate these conflicts, plots in a northern Californian coastal grassland were experimentally disturbed in the winter of 1990-1991; these plots differed in the area and intensity (depth) of the soil disturbance applied. When these plots were revisited after 10 growing seasons, patterns of revegetation differed significantly from those observed early in recolonization (0-3 years). At the earlier samplings, exotic annual grasses rapidly increased in most disturbance types. After 10 years, these exotic annuals had retreated from the depth experiment, which had recovered to a vegetation dominated by native perennials in all but the most severely disturbed plots. In contrast, although differences between control and disturbed plots also disappeared in the area experiment, the average abundance of aliens did not decline substantially relative to 1993 levels, especially in larger disturbances. Nonetheless, populations of aliens remained small compared to the peak populations in the depth experiment, probably reflecting wetter soils at the site used for the area experiment. These results differ from those of other recent studies of soil disturbance in coastal Californian ecosystems, which indicate disturbance may result in the permanent replacement of native perennial vegetation by dense populations of exotic annual grasses. This difference may reflect the high resilience of northern coastal grasslands as well as the scale of disturbances considered by different studies.