Statistics for Spatial Data.

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Landslide inventory maps: New tools for an old problem

Foreword 1. Introduction 2. Runoff, erosion and delivery to the coastal ocean 3. Temporal variations 4. Human impacts Appendices. Global River Database: Appendix A: North and Central America Appendix B: South America Appendix C: Europe Appendix D: Africa Appendix E: Eurasia Appendix F: Asia Appendix G: Oceania References Index.

/pdf/river-discharge-to-the-coastal-ocean-a-global-synthesis-571z1g19ts.pdf

River Discharge to the Coastal Ocean: A Global Synthesis

The Prediction in Ungauged Basins (PUB) initiative of the International Association of Hydrological Sciences (IAHS), launched in 2003 and concluded by the PUB Symposium 2012 held in Delft (23–25 October 2012), set out to shift the scientific culture of hydrology towards improved scientific understanding of hydrological processes, as well as associated uncertainties and the development of models with increasing realism and predictive power. This paper reviews the work that has been done under the six science themes of the PUB Decade and outlines the challenges ahead for the hydrological sciences community.Editor D. KoutsoyiannisCitation Hrachowitz, M., Savenije, H.H.G., Bloschl, G., McDonnell, J.J., Sivapalan, M., Pomeroy, J.W., Arheimer, B., Blume, T., Clark, M.P., Ehret, U., Fenicia, F., Freer, J.E., Gelfan, A., Gupta, H.V., Hughes, D.A., Hut, R.W., Montanari, A., Pande, S., Tetzlaff, D., Troch, P.A., Uhlenbrook, S., Wagener, T., Winsemius, H.C., Woods, R.A., Zehe, E., and Cudennec, C., 2013. A d...

/pdf/a-decade-of-predictions-in-ungauged-basins-pub-a-review-2g78unzpne.pdf

A decade of Predictions in Ungauged Basins (PUB)—a review

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS. For an overview of USGS information products, including maps, imagery, and publications, Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. 10. Diagram showing the GMTED2010 layer extents (minimum and maximum latitude and longitude) are a result of the coordinate system inherited from the 1-arc-second SRTM

Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010)

Stable reticulate structures, which we call “stone cells,” have been observed in cobble-gravel channel beds with low bed material transport rates. Experiments show that such structures develop simultaneously with the armor layer during an extended period when flows do not exceed the Shields threshold by more than ∼2 times, so that bed material transport is low. They are constructed by particles moving from less stable positions into more stable configurations against each other. Intermediate developments include clusters and stone lines. They reduce sediment transport by orders of magnitude and are evidently a major stability-promoting mechanism in gravel channels. The timescale for their development suggests that the boundaries of many gravel-bed channels are not in equilibrium with recent competent flows but reflect the history of recent “dominant” flows.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/98WR00484

Stabilizing self-organized structures in gravel-bed stream channels: Field and experimental observations

Headwater streams comprise 60 to 80 percent of the cumulative length of river networks. In hilly to mountainous terrain, they reflect a mix of hillslope and channel processes because of their close proximity to sediment source areas. Their morphology is an assemblage of residual soils, landslide deposits, wood, boulders, thin patches of poorly sorted alluvium, and stretches of bedrock. Longitudinal profiles of these channels are strongly influenced by steps created by sediment deposits, large wood, and boulders. Due to the combination of small drainage area, stepped shallow gradient, large roughness elements, and cohesive sediments, headwater streams typically transport little sediment or coarse wood debris by fluvial processes. Consequently, headwaters act as sediment reservoirs for periods spanning decades to centuries. The accumulated sediment and wood may be episodically evacuated by debris flows, debris floods, or gully erosion and transported to larger channels. In mountain environments, these processes deliver significant amounts of materials that form riverine habitats in larger channels. In managed steepland forests, accelerated rates of landslides and debris flows resulting from the harvest of headwater forests have the potential to seriously impact the morphology of headwater streams and downstream resources.

Geomorphology of steepland headwaters: the transition from hillslopes to channels

Landslide inventory in a rugged forested watershed: a comparison between air-photo and field survey data

We have examined the relation between the mean distance of movement during individual flood events and the mean particle size of unconstrained clasts in gravel bed rivers. Distance of movement was scaled using the mean distance of movement of the median size group of the surface material; size was scaled using the median b axis diameter of the subsurface material. The scaled data are fitted with a nonlinear function. Clasts larger than the median of surface material exhibit a steep decline of mobility, with an upper limit for mobility near Di/D50sub = 10. Smaller materials exhibit a less sensitive relation. We suppose that trapping of small clasts affects their travel distance. These results indicate that the movement of free surface stones is size preferred. A subordinate analysis of free, constrained and buried particles reveals that bed surface structure acts to reduce differential movement.

Size and Distance of Travel of Unconstrained Clasts on a Streambed

Distributions of distance of bedload particle movement were examined in two gravel bed streams using several hundred magnetically tagged cobbles and pebbles. The compound Poisson model of Einstein-Hubbell-Sayre and a simple gamma function model were compared with observed distributions of moved particles, and of all particles. Both models fit the data reasonably well for small mean displacements, but notable misfits occurred in an event with large mean displacement. When mean particle travel distance approaches the scale of bar spacing, trapping in the bars interrupts particle progress and the dispersion process. The data remain very noisy, so definitive discrimination of suitable models will require trials with more than 103 particles.

Marwan A. Hassan

Papers

Stabilizing self-organized structures in gravel-bed stream channels: Field and experimental observations

Geomorphology of steepland headwaters: the transition from hillslopes to channels

Landslide inventory in a rugged forested watershed: a comparison between air-photo and field survey data

Size and Distance of Travel of Unconstrained Clasts on a Streambed

Distance of movement of coarse particles in gravel bed streams