2013
Handwerger, Alexander L.; Roering, Joshua J.; Schmidt, David A.
Controls on the seasonal deformation of slow-moving landslides Journal Article
In: Earth and Planetary Science Letters, vol. 377-378, pp. 239–247, 2013.
Abstract | Links | BibTeX | Tags: ERCZO, hydrology, InSAR, landslides, LiDAR, pore-water pressure diffusion, precipitation
@article{Handwergera2013,
title = {Controls on the seasonal deformation of slow-moving landslides},
author = {Alexander L. Handwerger and Joshua J. Roering and David A. Schmidt},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Handwerger_2013_EarthPlanSciLetters.pdf},
doi = {10.1016/j.epsl.2013.06.047},
year = {2013},
date = {2013-09-01},
journal = {Earth and Planetary Science Letters},
volume = {377-378},
pages = {239–247},
abstract = {Precipitation drives seasonal velocity changes in slow-moving landslides by increasing pore-water pressure and reducing the effective normal stress along basal shear zones. This pressure change is often modeled as a pore-water pressure wave that diffuses through the landslide body, such that the minimum time required for landslides to respond to rainfall should vary as the square of landslide depth (which often approximates the saturated thickness) and inversely with hydraulic diffusivity. Here, we assess this model with new observations from the landslide-prone Eel River catchment, Northern California. Using satellite radar interferometry (InSAR) time series, precipitation data, and high-resolution topographic data from airborne lidar, we quantify the seasonal dynamics of 10 slow-moving landslides, which share the same lithologic, tectonic, and Mediterranean climate conditions. These slope failures have areas ranging from 0.16 to 3.1 km2, depths that vary from 8 to 40 m, and average downslope velocities of 0.2 to 1.2 m/yr. Each slide exhibits well-defined seasonal velocity changes with a periodicity of ∼1 yr and responds (i.e., accelerates) within 40 days following the onset of rainfall. Despite a five-fold variation in landslide depth, we do not detect systematic differences in response time within the resolution of our observations. Our results could imply that: 1) slides in our study area are sensitive to subtle hydrologic perturbations, 2) the ‘effective’ diffusivity governing slide behavior is much higher than field-derived values because pore pressure transmission and slide dynamics are facilitated by preferential flow paths, particularly cracks related to deformation and seasonal shrink-swell cycles, or 3) a simple one-dimensional linear diffusion model may fail to capture the three-dimensional time-dependent hydrologic changes inherent in an evolving mechanical–hydrologic system, such as a slow-moving landslide.},
keywords = {ERCZO, hydrology, InSAR, landslides, LiDAR, pore-water pressure diffusion, precipitation},
pubstate = {published},
tppubtype = {article}
}
Precipitation drives seasonal velocity changes in slow-moving landslides by increasing pore-water pressure and reducing the effective normal stress along basal shear zones. This pressure change is often modeled as a pore-water pressure wave that diffuses through the landslide body, such that the minimum time required for landslides to respond to rainfall should vary as the square of landslide depth (which often approximates the saturated thickness) and inversely with hydraulic diffusivity. Here, we assess this model with new observations from the landslide-prone Eel River catchment, Northern California. Using satellite radar interferometry (InSAR) time series, precipitation data, and high-resolution topographic data from airborne lidar, we quantify the seasonal dynamics of 10 slow-moving landslides, which share the same lithologic, tectonic, and Mediterranean climate conditions. These slope failures have areas ranging from 0.16 to 3.1 km2, depths that vary from 8 to 40 m, and average downslope velocities of 0.2 to 1.2 m/yr. Each slide exhibits well-defined seasonal velocity changes with a periodicity of ∼1 yr and responds (i.e., accelerates) within 40 days following the onset of rainfall. Despite a five-fold variation in landslide depth, we do not detect systematic differences in response time within the resolution of our observations. Our results could imply that: 1) slides in our study area are sensitive to subtle hydrologic perturbations, 2) the ‘effective’ diffusivity governing slide behavior is much higher than field-derived values because pore pressure transmission and slide dynamics are facilitated by preferential flow paths, particularly cracks related to deformation and seasonal shrink-swell cycles, or 3) a simple one-dimensional linear diffusion model may fail to capture the three-dimensional time-dependent hydrologic changes inherent in an evolving mechanical–hydrologic system, such as a slow-moving landslide.
Power, Mary E.; Holomuzki, Joseph R.; Lowe, Rex L.
Food webs in Mediterranean rivers Journal Article
In: Hydrobiologia, vol. 719, no. 1, pp. 119-136, 2013.
Abstract | Links | BibTeX | Tags: Algal production, Cross-ecosystem fluxes, Detritus Disturbance, Drought, fate Carbon sources, Floods, Food quality, food webs, hydrology, Insect emergence, interaction strength, Mediterranean rivers, River-to-ocean fluxes, seasonality
@article{Power2013,
title = {Food webs in Mediterranean rivers},
author = {Mary E. Power and Joseph R. Holomuzki and Rex L. Lowe},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Power_2013_Hydrobio.pdf},
doi = {10.1007/s10750-013-1510-0},
year = {2013},
date = {2013-05-28},
journal = {Hydrobiologia},
volume = {719},
number = {1},
pages = {119-136},
abstract = {River food webs are subject to two regimes of longitudinally varying ecological control: productivity and disturbance. Light-limited productivity increases as channels widen downstream. Time windows for growth, however, shrink as discharge increases, substrate particle size decreases, and the frequency of flood-driven bed mobilization increases downstream. Mediterranean rivers are periodically reset by hydrologic events with somewhat predictable timing. Typically, a rainy winter with high river discharge is followed by summer drought with little or no rainfall and slowly declining river flow. The magnitude and timing of winter floods and severity of subsequent summer drought can vary considerably from year to year, however. Episodic scouring floods or prolonged periods of drought are experienced as disturbances, stressors, or opportunities by river biota. The timing, duration, and intensity of these hydrologic controls affect performances of individuals, distribution and abundances of populations, and outcomes and consequences of species interactions. These interactions in turn determine how river food webs will assemble, develop, and reconfigure after disturbance. We discuss how spatial variation in solar radiation and spatial and temporal variations in disturbance affects river food webs under Mediterranean climate seasonality, focusing primarily on long-term observations in the Eel River of northwestern California, USA},
keywords = {Algal production, Cross-ecosystem fluxes, Detritus Disturbance, Drought, fate Carbon sources, Floods, Food quality, food webs, hydrology, Insect emergence, interaction strength, Mediterranean rivers, River-to-ocean fluxes, seasonality},
pubstate = {published},
tppubtype = {article}
}
River food webs are subject to two regimes of longitudinally varying ecological control: productivity and disturbance. Light-limited productivity increases as channels widen downstream. Time windows for growth, however, shrink as discharge increases, substrate particle size decreases, and the frequency of flood-driven bed mobilization increases downstream. Mediterranean rivers are periodically reset by hydrologic events with somewhat predictable timing. Typically, a rainy winter with high river discharge is followed by summer drought with little or no rainfall and slowly declining river flow. The magnitude and timing of winter floods and severity of subsequent summer drought can vary considerably from year to year, however. Episodic scouring floods or prolonged periods of drought are experienced as disturbances, stressors, or opportunities by river biota. The timing, duration, and intensity of these hydrologic controls affect performances of individuals, distribution and abundances of populations, and outcomes and consequences of species interactions. These interactions in turn determine how river food webs will assemble, develop, and reconfigure after disturbance. We discuss how spatial variation in solar radiation and spatial and temporal variations in disturbance affects river food webs under Mediterranean climate seasonality, focusing primarily on long-term observations in the Eel River of northwestern California, USA
2003
Howard, Jeanette K.; Cuffey, Kurt M.
Freshwater mussels in a California North Coast Range river: occurrence, distribution, and controls Journal Article
In: Journal of the North American Benthological Society, vol. 22, no. 1, pp. 63-77, 2003.
Abstract | Links | BibTeX | Tags: California, freshwater mussels, geomorphology, hydraulic model, hydrology, microhabitat, shear stress, South Fork Eel River
@article{Howard2003,
title = {Freshwater mussels in a California North Coast Range river: occurrence, distribution, and controls},
author = {Jeanette K. Howard and Kurt M. Cuffey},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Howard_2003_JouNorthAmerBenthoSoc.pdf},
doi = {10.2307/1467978},
year = {2003},
date = {2003-03-01},
journal = {Journal of the North American Benthological Society},
volume = {22},
number = {1},
pages = {63-77},
abstract = {We report the occurrence and habitat of mussel populations within a continuous 8-km section of the South Fork Eel River in the Northern Coast Range of California. The primary goals of our study were 1) to compile information on species composition and population density, and 2) to examine whether spatial distribution and variability were related to geomorphology and hydrology. High discharges almost certainly provide more of a constraint on the distribution and persistence of
mussels in the South Fork Eel than do low summer flows, so we used the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic model to estimate physical conditions during high flows when in-channel investigations were not feasible. We found numerous individuals of 2 species (Margaritifera falcata and Anodonta californiensis), with the spatial distribution of both species
characterized by high variability. Mussels in this system live almost exclusively in pools (with a few in runs), near the channel banks, and especially among sedge root-mat substrate. In all flow regimes (summer, winter, 5-y flood, and the largest floods on record), we found mussels in areas of lower boundary shear stresses and lower velocities. Our study suggests that, at various spatial scales, mussels appear to be distributed in a manner that protects them from the highest flow-induced stresses.},
keywords = {California, freshwater mussels, geomorphology, hydraulic model, hydrology, microhabitat, shear stress, South Fork Eel River},
pubstate = {published},
tppubtype = {article}
}
We report the occurrence and habitat of mussel populations within a continuous 8-km section of the South Fork Eel River in the Northern Coast Range of California. The primary goals of our study were 1) to compile information on species composition and population density, and 2) to examine whether spatial distribution and variability were related to geomorphology and hydrology. High discharges almost certainly provide more of a constraint on the distribution and persistence of
mussels in the South Fork Eel than do low summer flows, so we used the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic model to estimate physical conditions during high flows when in-channel investigations were not feasible. We found numerous individuals of 2 species (Margaritifera falcata and Anodonta californiensis), with the spatial distribution of both species
characterized by high variability. Mussels in this system live almost exclusively in pools (with a few in runs), near the channel banks, and especially among sedge root-mat substrate. In all flow regimes (summer, winter, 5-y flood, and the largest floods on record), we found mussels in areas of lower boundary shear stresses and lower velocities. Our study suggests that, at various spatial scales, mussels appear to be distributed in a manner that protects them from the highest flow-induced stresses.
mussels in the South Fork Eel than do low summer flows, so we used the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic model to estimate physical conditions during high flows when in-channel investigations were not feasible. We found numerous individuals of 2 species (Margaritifera falcata and Anodonta californiensis), with the spatial distribution of both species
characterized by high variability. Mussels in this system live almost exclusively in pools (with a few in runs), near the channel banks, and especially among sedge root-mat substrate. In all flow regimes (summer, winter, 5-y flood, and the largest floods on record), we found mussels in areas of lower boundary shear stresses and lower velocities. Our study suggests that, at various spatial scales, mussels appear to be distributed in a manner that protects them from the highest flow-induced stresses.
1996
Kupferberg, Sarah J.
Hydrologic and geomorphic factors affecting conservation of a river-breeding frog (Rana boylii) Journal Article
In: Ecological Applications, vol. 6, no. 4, pp. 1332-1344, 1996.
Abstract | Links | BibTeX | Tags: amphibians, Anura, frogs, geomorphology, hydrology, oviposition, physical habitat, Rana boylii, reproductive success, river, spatial scale
@article{Kupferberg1996,
title = {Hydrologic and geomorphic factors affecting conservation of a river-breeding frog (Rana boylii)},
author = {Sarah J. Kupferberg},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Kupferberg_EcolApp1996.pdf},
doi = {http://dx.doi.org/10.2307/2269611},
year = {1996},
date = {1996-11-00},
journal = {Ecological Applications},
volume = {6},
number = {4},
pages = {1332-1344},
abstract = {Organisms that live in highly variable environments, such as rivers, rely on adaptations to withstand and recover from disturbance. These adaptations include behavioral traits, such as habitat preference and plasticity of reproductive timing, that minimize the effects of discharge fluctuation. Studies linking hydrologic regime, habitat preference, and population processes, however, are predominantly limited to fish. Information on other sensitive taxa is necessary to facilitate conservation of multispecies assemblages and restoration of biodiversity in degraded river channels. I studied the functional relationship between physical habitat and reproduction of the foothills yellow-legged frog (Rana boylii), a California State Species of Special Concern. From 1992 to 1994, I mapped breeding sites along 5.3 km of the South Fork Eel River in northern California and monitored egg survival to hatching. Frogs selected sites over a range of spatial scales and timed their egg-laying to avoid fluctuations in river stage and current velocity associated with changes in discharge. The main sources of mortality were desiccation and subsequent predation of eggs in a dry year and scour from substrate in wet years, both caused by changes in stage and velocity. At the finest spatial scale, frogs attached eggs to cobbles and boulders at lower than ambient flow velocities. At larger scales, breeding sites were near confluences of tributary drainages and were located in wide, shallow reaches. Clutches laid in relatively narrower and deeper channels had poor survival in rainy as well as dry springs. Most breeding sites were used repeatedly, despite between- and within-year variation in spring stage of the river. This pattern of site selection suggests that conservation of Rana boylii may be enhanced by maintaining or restoring channels with shapes that provide stable habitat over a range of river stages.},
keywords = {amphibians, Anura, frogs, geomorphology, hydrology, oviposition, physical habitat, Rana boylii, reproductive success, river, spatial scale},
pubstate = {published},
tppubtype = {article}
}
Organisms that live in highly variable environments, such as rivers, rely on adaptations to withstand and recover from disturbance. These adaptations include behavioral traits, such as habitat preference and plasticity of reproductive timing, that minimize the effects of discharge fluctuation. Studies linking hydrologic regime, habitat preference, and population processes, however, are predominantly limited to fish. Information on other sensitive taxa is necessary to facilitate conservation of multispecies assemblages and restoration of biodiversity in degraded river channels. I studied the functional relationship between physical habitat and reproduction of the foothills yellow-legged frog (Rana boylii), a California State Species of Special Concern. From 1992 to 1994, I mapped breeding sites along 5.3 km of the South Fork Eel River in northern California and monitored egg survival to hatching. Frogs selected sites over a range of spatial scales and timed their egg-laying to avoid fluctuations in river stage and current velocity associated with changes in discharge. The main sources of mortality were desiccation and subsequent predation of eggs in a dry year and scour from substrate in wet years, both caused by changes in stage and velocity. At the finest spatial scale, frogs attached eggs to cobbles and boulders at lower than ambient flow velocities. At larger scales, breeding sites were near confluences of tributary drainages and were located in wide, shallow reaches. Clutches laid in relatively narrower and deeper channels had poor survival in rainy as well as dry springs. Most breeding sites were used repeatedly, despite between- and within-year variation in spring stage of the river. This pattern of site selection suggests that conservation of Rana boylii may be enhanced by maintaining or restoring channels with shapes that provide stable habitat over a range of river stages.