Mountain Drainage Basins Research Articles

Frequency and spatial distribution of landslides in a mountainous drainage basin: Western Foothills, Taiwan

Maps from 1904 and 1915 and air photographs from 1963, 1980, 1985, 1993 and 1996 provide a record of landslide incidence in a 92.1-km 2 drainage basin, a headwater tributary of the Cho-Shui River in Taiwan. Interpretation of landslide patterns from the early maps indicate that in four sub-basins (36 km 2) structural geological factors control chronic landsliding regularly reactivated by intense rains. Within these four sub-basins, all later air photographs reveal a continuing high incidence of landslides (with landslide densities of 3–11 ha/km 2). Air photographs taken in 1963, following extensive logging, in 1985, following highway construction, and in 1996, following the very large typhoon Herb event demonstrate the short-term effects of disturbance in these structurally weak sub-basins. Air photographs from 1980 and 1993 demonstrate recovery of the land surface from logging and highway construction impacts, respectively. For the adjacent sub-basins (56 km 2), two modes of response to perturbations were identified: six sub-basins (48 km 2) showed direct response to logging, road construction and typhoon Herb and five sub-basins (8 km 2) were more buffered and showed some lagged responses. Even this last category of sub-basins is more active than the average for Taiwan, where the mean landslide density is 0.84 ha/km 2. It is proposed that, for the 92.1-km 2 Hoshe basin, the ‘formative event’ sensu Brunsden [Z. Geomorphol. Suppl. 79 (1990) 1] is one that produces approximately 200 ha of landslides, a value that has been equaled or exceeded in each of the periods of study (1963–1980, 1980–1985, 1985–1993 and 1993–1996). Logging activity, major road construction, and extreme typhoon and earthquake events produce short-term acceleration of landslide incidence. In principle, recovery rates of the land from pulsed perturbations of about 20 years for logging activity and about 8 years for major road construction may also be suggested.

Photogrammetric Analysis of a Slush Torrent in the Kärkevagge, Northern Sweden

Slushflows have been investigated in various regions of the Earth for more than forty years. Most of the observed events occurred in mountainous drainage basins at high latitudes, so relatively few observations and measurements are presented in the scientific literature. This particularly holds for slush torrents which are major slushflow events reaching supercritical flow velocities. Thus, information on dynamical features of slush torrents are rather limited, and most results are based on qualitative observations. On June 3,1995, during a field campaign in the Kärkevagge, a drainage basin in Swedish Lapland, a slush torrent could be observed and documented by a time series of photographs and by video recordings. Quantitative results from a photogrammetric analysis of the photographs show that the first wave front of that slush torrent reached peak velocities of more than 40 ms−1. A second wave front was able to reach even higher velocities due to the fact that the first wave had almost completely removed all snow from the transport path. Consequently, the viscosity of the flow was significantly reduced. To the author's best knowledge, these results are the first quantitative measurements of a slush torrent during its movement.

Effects of punctuated sediment supply on valley-floor landforms and sediment transport

Research Article| December 01, 2000 Effects of punctuated sediment supply on valley-floor landforms and sediment transport Daniel J. Miller; Daniel J. Miller 1Earth Systems Institute, 1314 North East 43rd Street, Seattle, Washington 98105, USA Search for other works by this author on: GSW Google Scholar Lee E. Benda Lee E. Benda 1Earth Systems Institute, 1314 North East 43rd Street, Seattle, Washington 98105, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2000) 112 (12): 1814–1824. https://doi.org/10.1130/0016-7606(2000)112<1814:EOPSSO>2.0.CO;2 Article history received: 18 Feb 1999 rev-recd: 15 Sep 1999 accepted: 15 Nov 1999 first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Daniel J. Miller, Lee E. Benda; Effects of punctuated sediment supply on valley-floor landforms and sediment transport. GSA Bulletin 2000;; 112 (12): 1814–1824. doi: https://doi.org/10.1130/0016-7606(2000)112<1814:EOPSSO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Large, infrequent fluxes of sediment to streams by mass wasting are intrinsic to the erosion regime of mountain drainage basins. To elucidate the role of mass wasting in the construction and evolution of steep land channel environments, it is crucial that we identify the processes involved and recognize their legacy on the valley floor. In the winter of 1996, nine storm-triggered debris flows carried ∼18 000 m3 of coarse debris into the upper reaches of the South Fork of Gate Creek (Oregon Cascade Range) during flood flow. Analysis of resulting channel morphologies and bed textures shows that the sediment moved downstream as a wave-like pulse or pulses, overwhelming the channel and causing it to braid, with flooding and alluvial deposition over the valley floor. Downstream progression of the sediment wave resulted in vertical accretion of the valley floor with sediment carried as bedload, the maximum depth of valley-floor burial being set by the amplitude of the wave. Passage of the wave left a channel incised to bedrock, inset between coarse-grained alluvial terraces. This study examines the genesis of these features at Gate Creek and points to such terraces as field indicators of massive episodic influxes of sediment and the associated formation of fluvially transported sediment waves. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Measurement and estimative models of glacier mass balance in china

Attributed to high altitude and inland location, the glaciers in China are characterized by very low temperature. The non‐negligible contribution of up to 25% of superimposed ice to the net balance has been taken into account in the mass budget calculation. So too has the internal the accumulation in the infiltration zone of the accumulation area.The prevailing monsoon climate delivers most of the annual precipitation over glaciated areas of China in the summer, making the major accumulation on those glaciers coincide with the ablation period. Therefore, the annual mass balance should be calculated neither by giving the place of annual accumulation to winter balance, nor annual ablation to summer balance. Rather, it is better done by net accumulation and net ablation during the year. In order to get the annual accumulation and the annual ablation on a glacier, the summer precipitation should be measured at the same time.Frequent snowfall in the summer season results in intensive fluctuation of surface albedo. This means that, for lack of data on the extremes of ablation, reconstruction of mass balance is unsatisfactory when based on the relationships of accumulation and ablation to precipitation and temperature. The establishment of models, either on the relationship of multi‐year mass balance to the equilibrium line and the mass balance gradient of a glacier in steady‐state, or on the maximum entropy principle and the hydrometeorological data, helps to estimate the multi‐year mass balance of the glacierized area in a mountain range or drainage basin.

Dynamics of the stream‐power river incision model: Implications for height limits of mountain ranges, landscape response timescales, and research needs

The longitudinal profiles of bedrock channels are a major component of the relief structure of mountainous drainage basins and therefore limit the elevation of peaks and ridges. Further, bedrock channels communicate tectonic and climatic signals across the landscape, thus dictating, to first order, the dynamic response of mountainous landscapes to external forcings. We review and explore the stream‐power erosion model in an effort to (1) elucidate its consequences in terms of large‐scale topographic (fluvial) relief and its sensitivity to tectonic and climatic forcing, (2) derive a relationship for system response time to tectonic perturbations, (3) determine the sensitivity of model behavior to various model parameters, and (4) integrate the above to suggest useful guidelines for further study of bedrock channel systems and for future refinement of the streampower erosion law. Dimensional analysis reveals that the dynamic behavior of the stream‐power erosion model is governed by a single nondimensional group that we term the uplift‐erosion number, greatly reducing the number of variables that need to be considered in the sensitivity analysis. The degree of nonlinearity in the relationship between stream incision rate and channel gradient (slope exponent n) emerges as a fundamental unknown. The physics of the active erosion processes directly influence this nonlinearity, which is shown to dictate the relationship between the uplift‐erosion number, the equilibrium stream channel gradient, and the total fluvial relief of mountain ranges. Similarly, the predicted response time to changes in rock uplift rate is shown to depend on climate, rock strength, and the magnitude of tectonic perturbation, with the slope exponent n controlling the degree of dependence on these various factors. For typical drainage basin geometries the response time is relatively insensitive to the size of the system. Work on the physics of bedrock erosion processes, their sensitivity to extreme floods, their transient responses to sudden changes in climate or uplift rate, and the scaling of local rock erosion studies to reach‐scale modeling studies are most sorely needed.

PROCESS DOMAINS AND THE RIVER CONTINUUM1

ABSTRACT: The concept of process domains is proposed as an alternative to the River Continuum Concept for the influence of geomorphic processes on aquatic ecosystems. Broadly defined, the Process Domain Concept is a multi‐scale hypothesis that spatial variability in geomorphic processes governs temporal patterns of disturbances that influence ecosystem structure and dynamics. At a coarse scale, regional climate, geolog vegetation, and topography control the suite of geomorphic processes that are distributed over a landscape. Within the broad context so defined, stream channel classification can guide identification of functionally similar portions of a channel network, but the response of otherwise similar reaches can depend upon their geologic and geomorphic context. Within geomorphic provinces defined by differences in topography, climate history, and tectonic setting, areas with generally similar geology and topography define lithotopo units, which are useful for stratifying different suites of dominant geomorphic processes. Process domains are spatially identifiable areas characterized by distinct suites of geomorphic processes, and the Process Domain Concept implies that channel networks can be divided into discrete regions in which community structure and dynamics respond to distinctly different disturbance regimes. The concepts of process domains and lithotopo units provide both a framework for the application of patch dynamics concepts to complex landscapes and a context for addressing the effects of watershed processes on the ecology of mountain drainage basins.

Channel type and salmonid spawning distribution and abundance

Consideration of fundamental channel processes, together with map-based and field investigations, indicates that stream channel type influences salmonid spawning distributions across entire channel networks and salmonid abundance within channel reaches. Our analysis suggests that salmonid spawning patterns in mountain drainage basins of the Pacific Northwest are adapted to, among other things, the timing and depth of channel bed mobility. We hypothesize that because the bed of pool-riffle and plane-bed reaches scours to a variable fraction of the thickness of alluvium, survival to emergence is favored by either burying eggs below the annual scour depth or avoiding egg burial during times of likely bed mobility. Conversely, annual mobility of all available spawning gravel in steeper step-pool and cascade channels favors either adaptations that avoid egg burial during times of likely bed mobility or selection of protected microhabitats. Consistent with these expectations, we find that salmonid spawning distributions track channel slope distributions in several west-slope Pacific Northwest watersheds, implying that spatial differences in channel processes influence community structure in these rainfall-dominated drainage basins. More detailed field surveys confirm that different channel types host differential use by spawning salmonids and reveal finer-scale influences of pool spacing on salmonid abundance.

CRITICAL DATA REQUIREMENTS FOR PREDICTION OF EROSION AND SEDIMENTATION IN MOUNTAIN DRAINAGE BASINS1

ABSTRACT: The potential for understanding and, where necessary, managing sedimentation in humid mountain drainage basins increases with awareness of the conditions that lead to shallow landsliding, debris flows, and catastrophic sedimentation in stream channels. Progress in understanding has involved: improved recognition of source areas and the potential for downstream effects of slope failure; improved understanding of hydrological conditions required for failure; and a general theory of slope stability in shallow colluvium, including the role of plants, fires, timber harvest, and other disturbances. The theory acknowledges spatial variability in topographic and geotechnical terrain characteristics, the stochastic nature of climatic triggering events such as forest fires and rainstorms, and the integrating nature of channel networks in modulating the cumulative effects of transient processes within a basin. Anthropogenic fire regimes, road effects, and timber harvest can readily be included. Continued application and modification of the theory over an expanded geographical range require improvements in field data and their systematic storage in spatial databases. Improvements in digital topographic data for mountain basins, systematic network‐wide surveys of channel conditions, and new technology for rapid documentation of soil depths in landslide source areas would enhance the prediction of mass failure, its consequences for channel habitat, and the basin‐wide or regional distribution of hillslope and channel conditions. Computations of the probabilities of transient effects throughout basins could then form the basis of ecological risk analyses. Large‐scale spatial data sets of a few critical variables are required before this next level of understanding can be developed and applied to sedimentation impacts on ecosystems and other resources.

Effects of quarry mining and of other environmental impacts in the mountainous Chicam-Toctina drainage basin (Córdoba, Argentina)

The environmental conditions prevailing in the Chicam-Toctina drainage system (approx. 138 km2 in Cordoba, Argentina) are considered representative of a number of catchments in Argentina's Sierras Pampeanas Range. Two groups of ions reflect the sources of dissolved species in the catchment: a) a group (Cl–, SO2–4, and Na+) which recognizes natural and anthropogenic sources, and which exhibits significant correlations with N–3 and NO–2, and b) another group of components (Ca2+, Mg2+, and HCO–3) which is clearly controlled by carbonate rocks and their waste rock products. In the headwaters, stockpiled marble quarry mining wastes provide a more open system to CO2 gaseous exchange than the outcropping rocks, thus promoting the increase of carbonate dissolution (up to 4.88 g km–2 s–1 during the rainy season). This specific yield was 20% higher than the amount estimated for an area with fewer extended mining activities. The dissolved load delivered by the upper reaches is subjected in the lower drainage area to various processes, mainly controlled by the presence of the city of Alta Gracia (approx. 40,000 inhabitants). In the dry season, due to nutrient inputs supplied by the city, photosynthetic activity plays a major role controlling stream pH. Hence, the high values of calcite saturation indexes and the increase of CaCO3 concentration in bed sediments can be explained by calcite precipitation. Such a process could be accompanied by the coprecipitation on calcium carbonate of low solubility heavy metal carbonates.

Channel-reach morphology in mountain drainage basins

A classification of channel-reach morphology in mountain drainage basins synthesizes stream morphologies into seven distinct reach types: colluvial, bedrock, and five alluvial channel types (cascade, step pool , plane bed, pool rime, and dune ripple). Coupling reach-level channel processes with the spatial arrangement of reach morphologies, their links to hillslope processes, and external forcing by confinement, ripar­ ian vegetation, and woody debris defines a process-based framework within which to assess channel condition and response potential in mountain drainage basins. Field investigations demonstrate character­ istic slope, grain size, shear stress, and roughness ranges for different reach types, observations consistent with our hypothesis that alluvial channel morphologies reflect specific roughness configurations ad­ justed to the relative magnitudes of sediment supply and transport ca­ pacity. Steep alluvial channels (cascade and step pool) have high ratios of transport capacity to sediment supply and are resilient to changes in discharge and sediment supply, whereas low-gradient alluvial channels (pool rime and dune ripple) have lower transport capacity to supply ra­ tios and thus exhibit significant and prolonged response to changes in sediment supply and discharge. General differences in the ratio of transport capacity to supply between channel types allow aggregation of reaches into source, transport, and response segments, the spatial distribution of which provides a watershed-level conceptual model linking reach morphology and channel processes. These two scales of channel network classification define a framework within which to in­ vestigate spatial and temporal patterns of channel response in moun­ tain drainage basins.

Distribution of bedrock and alluvial channels in forested mountain drainage basins

MOUNTAIN river networks often consist of both bedrock and alluvial channels1–5, the spatial distribution of which controls several fundamental geomorphological and ecological processes6,7. The nature of river channels can influence the rates of river incision and landscape evolution1,2, as well as the stream habitat characteristics affecting species abundance and aquatic ecosystem structure8–11. Studies of the factors controlling the distribution of bedrock and alluvial channels have hitherto been limited to anthropogenic badlands12. Here we investigate the distribution of channel types in forested mountain drainage basins, and show that the occurrence of bedrock and alluvial channels can be described by a threshold model relating local sediment transport capacity to sediment supply. In addition, we find that valley-spanning log jams create alluvial channels— hospitable to aquatic life—in what would otherwise be bedrock reaches. The formation of such jams depends critically on the stabilizing presence of logs derived from the largest trees in the riverside forests, suggesting that management strategies that allow harvesting of such trees can have a devastating influence on alluvial habitats in mountain drainage basins.

Pool Spacing in Forest Channels

Field surveys of stream channels in forested mountain drainage basins in southeast Alaska and Washington reveal that pool spacing depends on large woody debris (LWD) loading and channel type, slope, and width. Mean pool spacing in pool‐riffle, plane‐bed, and forced pool‐riffle channels systematically decreases from greater than 13 channel widths per pool to less than 1 channel width with increasing LWD loading, whereas pool spacing in generally steeper, step‐pool channels is independent of LWD loading. Although plane‐bed and pool‐riffle channels occur at similar low LWD loading, they exhibit typical pool spacings of greater than 9 and 2–4 channel widths, respectively. Forced pool‐riffle channels have high LWD loading, typical pool spacing of &lt;2 channel widths, and slopes that overlap the ranges of free‐formed pool‐riffle and plane‐bed channel types. While a forced pool‐riffle morphology may mask either of these low‐LWD‐loading morphologies, channel slope provides an indicator of probable morphologic response to wood loss in forced pool‐riffle reaches. At all study sites, less than 40% of the LWD pieces force the formation of a pool. We also find that channel width strongly influences pool spacing in forest streams with similar debris loading and that reaches flowing through previously clear‐cut forests have lower LWD loading and hence fewer pools than reaches in pristine forests.

The relationship between altitude and relief intensity in high mountain drainage basins

The relationship between altitude and relief intensity in high mountain drainage basins

Channel network source representation using digital elevation models

Methods for identifying the size, or scale, of hillslopes and the extent of channel networks from digital elevation models (DEMs) are examined critically. We show that a constant critical support area, the method most commonly used at present for channel network extraction from DEMs, is more appropriate for depicting the hillslope/valley transition than for identifying channel heads. Analysis of high‐resolution DEMs confirms that a constant contributing area per unit contour length defines the extent of divergent topography, or the hillslope scale, although there is considerable variance about the average value. In even moderately steep topography, however, a DEM resolution finer than the typical 30 m by 30 m grid size is required to accurately resolve the hillslope/valley transition. For many soil‐mantled landscapes, a slope‐dependent critical support area is both theoretically and empirically more appropriate for defining the extent of channel networks. Implementing this method for overland flow erosion requires knowledge of an appropriate proportionality constant for the drainage area‐slope threshold controlling channel initiation. Several methods for estimating this constant from DEM data are examined, but acquisition of even limited field data is recommended. Finally, the hypothesis is proposed that an inflection in the drainage area‐slope relation for mountain drainage basins reflects a transition from steep debris flow‐dominated channels to lower‐gradient alluvial channels.

Soil-stratigraphic techniques in the study of soil and landform evolution across the Southern Alps, New Zealand

The Southern Alps lie along the convergent Pacific-Indian plate boundary. Geomorphically distinct eastern, axial and western regions reflect the east-west gradient in tectonic uplift (1 to 10 mm a−1) and precipitation (600 to 10,000 mm a−1). The eastern region is divided into front-ange and basin-and-range subregions. Soil-sequence studies on terraces established temporal contrasts in pedogenesis within and between eastern and western regions encompassing Entisols, Inceptisols and Spodosols. On Late Pleistocene and early Holocene terraces Dystrochrepts are persistent soils in the eastern region and Aquods in the western region. These soil sequences are used in the interpretation of relative soil age, stratigraphy and erosion history in hill and mountain drainage basins of the eastern and western regions. In the subhumid to humid eastern front-range subregion, simple soil forms occur as catenary sequences, and there is little evidence of erosion following the destruction of forests in the last millenium. Mollisols are dominant in the subhumid, and Dystrochrepts in humid areas, respectively. Soil-debris mantle regoliths date from the early Holocene and are still developing on slopes. The soil pattern on mountain slopes in the humid, eastern basin-and-range subregion is a complex array of simple, eroded, composite and compound soils. This pattern has resulted from erosion following forest destruction within the last millenium. The oldest surface or buried forest soils are Dystrochrepts dating from the Late Pleistocene to early Holocene. Wind erosion of these low-fertility soils contributes to the loessial sediments in which younger soils have formed. In the western region, soil patterns and soil stratigraphy indicate continous instability with a complex pattern of highly leached, shallow Orthents and bedrock outcrops on slopes. The soils are eroded from slopes within 2 ka. These contrasts in soil development and erosion periodicity in the eastern and western regions of the Southern Alps parallel the east-west contrasts in erosion rates of ca. 1–10 mm a−1.

Morphometric analysis of mountain drainage basins in the Basin and Range Province, USA

Morphometric analysis of mountain drainage basins in the Basin and Range Province, USA

Study of the Analysis of Sediment Yield and Discharge in Mountainous Drainage Basin

Study of the Analysis of Sediment Yield and Discharge in Mountainous Drainage Basin

Plant communities, landforms, and soils of a geomorphically active drainage basin, Southern Alps, New Zealand

Abstract The plant commumtles in a mountainous drainage basin in the Southern Alps, Westland, New Zealand, were classified from 92 vegetation descriptions. Nine forest and shrubland communities were defined from the presence/absence of 264 species and from differences in canopy cover. Their composition and distribution, inferred from ordination and descriptions of landforms and soils, were determined primarily by the influences of mass movement disturbance and elevation. Erosional and depositional landform units of varying age and surface stability contained soils of different stages of development. Seral communities occupied well-drained and often frequently disturbed recent soils. Mature forest/shrubland dominated stable landforms characterised by yellow-brown earths or gley podzol soils. Although specific relationships of individual species with factors such as soil nutrient status are consistent with other studies in Westland, landform age and surface stability, soil depth, soil drainage, and other physical disturbances, such as treefalls, appear to be equally critical determinants.

Great Controllers on Runoff from Mountain Drainage Basin

Great Controllers on Runoff from Mountain Drainage Basin

Correlates of habitat favourability for benthic macroinvertebrates at five stream sites in an Appalachian Mountain drainage basin, U.S.A.

SUMMARY. Based on monthly samples taken over a 1‐year period, average density (individuals m‐2). average standing biomass and annual production of benthic macroinvertebrates were estimated at five sites within an Appalachian Mountain drainage basin. Two sites were on first order streams and differed from the three second order sites: they were smaller and more shallow and they were depressed in pH and chemical richness. Patterns of abundance of individual taxa, of higher taxonomic groups and of functional (feeding) groups differed according to whether abundance was measured as density, as standing biomass or as annual production. Standing biomass was chosen as the measure of macroinvertebrate abundance because available evidence indicates that only standing biomass is consistently, positively correlated with survivorship, and thus with habitat favourability. Two non‐insect taxa (the crayfish Cambarus and the snail Leptoxis carinata) dominated standing biomass at each site. Consequently, differences among sites in total macroinvertebrate standing biomass and differences within and among sites in standing biomass of functional groups were determined by differences in estimated standing biomass of these two taxa. Differences in estimates of crayfish standing biomass were consistent with an explanation based on the availability of refuges created by large substrate particles. The abundance of L. carinata appeared to be controlled primarily by water chemistry and possibly secondarily by predators. A number of insect taxa exhibited patterns of standing biomass consistent with hypotheses based on effects of annual depth‐flow regimes. Hypotheses based on differences in food resource and on competition appeared, in general, to be inconsistent with observed patterns of macroinvertebrate abundance. Contrary to predictions of the River Continuum Concept, the shredder functional group in the Guys Run drainage and in other temperate woodland streams was found to be a minor part of total macroinvertebrate standing biomass. Further, in a majority of small forested stream sites studied to date, standing biomass of grazers has been determined to be greater than that of shredders.