LANDSCAPE PERMANENCE AND NUCLEAR WARNINGS

ABSTRACT. From the perspective of a human lifetime, the hazards of some nuclear wastes are permanent, so the warnings we place at contaminated nuclear sites must be permanent too. I address questions of how best to provide one hundred centuries of public warning at the first facility for permanent disposal, the Waste Isolation Pilot Plant in New Mexico. Scenarios of intrusion developed to guide the design of warning markers predicted that most of the changes in the area will be social and cultural. Because blatant and permanent markers will increase, not reduce, the probability of inadvertent intrusion, the most appropriate warning is a “landscape of illusion.” Such a landscape needs not permanent surface markers but underground warning devices beneath a soft surface marker. No warning can guarantee deterrence for 10,000 years, however.     

Comparison of flood hazard assessments on desert piedmonts and playas: A case study in Ivanpah Valley, Nevada

Accurate and realistic characterizations of flood hazards on desert piedmonts and playas are increasingly important given the rapid urbanization of arid regions. Flood behavior in arid fluvial systems differs greatly from that of the perennial rivers upon which most conventional flood hazard assessment methods are based. Additionally, hazard assessments may vary widely between studies or even contradict other maps. This study's chief objective was to compare and evaluate landscape interpretation and hazard assessment between types of maps depicting assessments of flood risk in Ivanpah Valley, NV, as a case study. As a secondary goal, we explain likely causes of discrepancy between data sets to ameliorate confusion for map users. Four maps, including three different flood hazard assessments of Ivanpah Valley, NV, were compared: (i) a regulatory map prepared by FEMA, (ii) a soil survey map prepared by NRCS, (iii) a surficial geologic map, and (iv) a flood hazard map derived from the surficial geologic map, both of which were prepared by NBMG. GIS comparisons revealed that only 3.4% (33.9 km²) of Ivanpah Valley was found to lie within a FEMA floodplain, while the geologic flood hazard map indicated that ~ 44% of Ivanpah Valley runs some risk of flooding (Fig. 2D). Due to differences in mapping methodology and scale, NRCS data could not be quantitatively compared, and other comparisons were complicated by differences in flood hazard class criteria and terminology between maps. Owing to its scale and scope of attribute data, the surficial geologic map provides the most useful information on flood hazards for land-use planning. This research has implications for future soil geomorphic mapping and flood risk mitigation on desert piedmonts and playas. The Ivanpah Valley study area also includes the location of a planned new international airport, thus this study has immediate implications for urban development and land-use planning near Las Vegas, NV.     

Acacia salicina, Pinus halepensis and Eucalyptus occidentalis improve soil surface conditions in arid southern Tunisia

Despite low growth rates, plants in arid areas have a strong ability to modify soil surface properties affecting ecosystem processes and community dynamics. But our knowledge on species effects on soil properties in these areas comes largely from observational studies, increasing the risk of confounding factors and precluding estimations of rates of change. We evaluated changes in soil surface properties underneath Acacia salicina, Pinus halepensis and Eucalyptus occidentalis in a 10-year-old common garden experiment established on a degraded Stipa tenacissima steppe in southern Tunisia. The three species tested improved soil properties compared to those of open areas. Acacia salicina ranked first as soil modifier as the soil underneath this species showed higher total organic carbon, total nitrogen, available phosphorus, soil CO₂ efflux and infiltration rate, and lower soil hydrophobicity than soil in open areas. The richness of vascular plants was higher under A. salicina than under the other types of cover. This species showed higher ability to improve microsite conditions and foster succession. Short rotations of A. salicina could thus be employed for the restoration of degraded S. tenacissima steppes provided that other aspects of its ecology are controlled. Pinus halepensis represents a good alternative when native species are a priority, albeit facilitative ability is lower.     

Late Tertiary paleoclimatic interpretation from lacustrine rhythmites in the Gray Fossil Site,northeastern Tennessee,USA

The Gray Fossil Site (GFS) includes a small (<2 ha) paleosinkhole lake fill with an exceptionally well-preserved record of sedimentation and fossils from the latest Miocene to earliest Pliocene. The uppermost lacustrine stratigraphy is characterized by rhythmites that regularly alternate between coarse-grained and organic-rich (A) laminae and fine-grained, silty clay (B) laminae. Both the A and B components are almost exclusively comprised of exogenic sediment (including organic matter). Periodicities of 24 and 4.4 are recorded within a continuous 96 interpreted year sequence of rhythmite sediment. In a small lake with a poorly oxygenated bottom, the presence of laterally continuous laminated sediment that includes well-known periodicities in rhythmite thickness is interpreted as representing annually generated varves that correspond to seasonal variations in sedimentation. The distinctly larger fraction of medium sand-size quartz grains present within the A laminae, as well as the abrupt transitions between A and B components suggest that the rhythmites represent deposition during alternating high-energy and lower-energy seasons, which is consistent with a monsoonal precipitation pattern. The seasonal climate may relate to changes in the ocean circulation pattern prior to 4.6 Ma that resulted in an increased temperature and atmospheric pressure gradient between the east coast of North America and the Atlantic Ocean, but this climate phase seems to be only a temporary condition, as underlying and overlying sediment are both consistent with drier conditions. The periodicity at 24 interpreted years is consistent with the well-known Hale solar cycle. The 4.4 interpreted-year periodicity occurs within the ENSO frequency band, and if this documentation of ENSO-like interannual climate change is correct, then it suggests that ENSO operated at times during the warm Earth conditions characterizing the late Tertiary.     

Will the Russians return from the near abroad?

The author "examines a range of issues surrounding the involuntary migration of Russian populations from the non-Russian republics of the former USSR. Among the questions addressed are possible magnitudes of in-migration into Russia (with special attention paid to conditions in one of the major source regions, Central Asia), attitudes in Russia regarding appropriate policy with respect to treatment of co-nationals in the near abroad and whether their return to Russia would have a positive or negative impact, and conditions in areas of Russia that presently are absorbing the greatest numbers of migrants. The assertion that Russian policy should seek aggressively to prevent the out-migration of Russian populations [from] the near abroad is assessed critically."     

Late Holocene dune activity in the Eastern Platte River Valley, Nebraska

Large-scale dune activity in the Nebraska Sand Hills and elsewhere on the western Great Plains has been linked to prehistoric “megadroughts” that triggered the activation of regional dune fields. The effect of megadroughts on the smaller dune fields east of the Nebraska Sand Hills has never been assessed, however. This study focuses on the Duncan dune field near the confluence of the Loup and Platte rivers in eastern Nebraska. Seventeen optically stimulated luminescence age estimates were obtained and reveal two periods of dune activation that occurred between 4.4 to 3.4 ka and 0.8 to 0.5 ka. Significantly, both periods chronologically overlap large-scale dune activity identified in the Nebraska Sand Hills. Geochemical evidence indicates that the Duncan dunes received sand not only from the terrace underlying them, but also from the Loup River. These data link dune activity in the Duncan area, at least indirectly, to increased sediment supply from streams that drain the Sand Hills during megadroughts, implying the activation of the dunes occurred as an indirect response to regional megadroughts. Calculations of dune migration rates, however, argue in favor of local, drought-driven hydrologic changes as a causative factor in dune activation, in other words, a direct effect of megadroughts. Whether the impact was direct or indirect, it is highly likely that the repeated reactivation of the Duncan dunes resulted in some way from regional, large-magnitude droughts. Other paleoclimate proxies from the Great Plains tend to support this conclusion. We conclude that the megadroughts that have been identified in the Sand Hills and other Great Plains dune fields were indeed regional events with far-reaching effects.     

Deriving hillslope sediment budgets in wildfire-affected forests using fallout radionuclide tracers

Information on post-fire sediment and nutrient redistribution is required to underpin post-fire catchment management decisions. Fallout radionuclide budgets (²¹⁰Pb_xs, ¹³⁷Cs and ⁷Be) were derived to quantify soil redistribution and sediment yield in forested terrain following a moderately severe wildfire in a small (89 ha) water supply catchment in SE Australia. Application of these techniques in burnt terrain requires careful consideration of the partitioning of radionuclides between organic and mineral soil components. Beryllium-7 and ²¹⁰Pb_xs were shown to be closely associated with ash, litter and soil organic matter whereas ¹³⁷Cs was more closely associated with subsurface coarse mineral soil. Comparison of the three tracer budgets indicated that the dominant sediment source areas were ridgetops and steep valley sideslopes, from which burnt surface material was conveyed to the stream network via pre-existing gullies. Erosion was predominantly driven by sheetwash, enhanced by soil water repellency, and modified by bioturbation which both supplies subsurface sediment and provides sinks for erosive overland flow. Footslope and riparian zones were not important sediment source areas. The estimated event-based (wildfire and subsequent rainfall) sediment yield is 58 ± 25 t km^− 2, based on fallout ⁷Be measurements. The upper estimate of total particulate phosphorus yield (0.70 kg ha^− 1) is more than 10 times that at equivalent unburnt sites. This illustrates that, soon after fire, burnt eucalypt forest can produce nutrient loads similar to those of agricultural catchments. The tracer budgets indicate that wildfire is an important control on sediment and phosphorus inputs to the stream network over the decadal timeframe and the pulsed nature of this release is an important concern for water quality management.     

The cold and wet year 1695 — a contemporary German account

After describing briefly some of the outstanding features of the uncommonly cold and wet year 1695, one of the coldest years of the Little Ice Age, an annotated translation is presented of a contemporary review of the unusual weather events of the year in Europe. The original was published in 1702 in Frankfurt am Main, Germany, in vol. XIV of the seriesTheatrum Europaeum. The annotation relates to the historical events of the year that were substantially affected by the weather, events to which rather abstruse references are made in the aforementioned contemporary account. In addition to the fact that the contemporary review describes the uncommon weather conditions of 1695, it appears to be the first extended weather review in history.