Periods Of Intense Rainfall Research Articles

Seismic analysis of the 13 October 2012 Te Maari, New Zealand, lake breakout lahar: Insights into flow dynamics and the implications on mass flow monitoring

On 6 August 2012 an eruption of the upper Te Maari vent Tongariro volcano and subsequent debris flow in the Mangatetipua channel created a debris dam and ephemeral lake. The lake reached its maximum volume of 50,000m3 by 13 October, initiating dam breaching at 22:30 NZDT (11:30 UTC) after a period of intense rainfall. The breach eventually grew to 29×12m, causing eroded debris flow sediment and water to remobilize as a lahar. The event, comprising multiple surges, lasted ~30min, and displaced 57,000m3 of remobilized sediment up to 4.5km downstream. To determine the dynamics of the event, the seismic signals generated by the lahar were compared with active seismic source data collected in February 2013. The comparison used a common frequency band range of 3–10Hz to compute amplitude for four near-field seismic stations. For periods with signal-to-noise ratios above 2.0, we obtained lahar amplitude distributions that match best the equivalent active source amplitudes within ~0.5km of the dam breakout. The accumulated seismic energy of the lahar was estimated at 1.93×109Nm, whereas the peak energy was 6.88×107Nm. Results of this work may improve the characterization of future mass flow events in the Te Maari/Mangatetipua area through the calibration of seismic stations used in this study.

A Regional Model for Malaria Vector Developmental Habitats Evaluated Using Explicit, Pond-Resolving Surface Hydrology Simulations.

Dynamical malaria models can relate precipitation to the availability of vector breeding sites using simple models of surface hydrology. Here, a revised scheme is developed for the VECTRI malaria model, which is evaluated alongside the default scheme using a two year simulation by HYDREMATS, a 10 metre resolution, village-scale model that explicitly simulates individual ponds. Despite the simplicity of the two VECTRI surface hydrology parametrization schemes, they can reproduce the sub-seasonal evolution of fractional water coverage. Calibration of the model parameters is required to simulate the mean pond fraction correctly. The default VECTRI model tended to overestimate water fraction in periods subject to light rainfall events and underestimate it during periods of intense rainfall. This systematic error was improved in the revised scheme by including the a parametrization for surface run-off, such that light rainfall below the initial abstraction threshold does not contribute to ponds. After calibration of the pond model, the VECTRI model was able to simulate vector densities that compared well to the detailed agent based model contained in HYDREMATS without further parameter adjustment. Substituting local rain-gauge data with satellite-retrieved precipitation gave a reasonable approximation, raising the prospects for regional malaria simulations even in data sparse regions. However, further improvements could be made if a method can be derived to calibrate the key hydrology parameters of the pond model in each grid cell location, possibly also incorporating slope and soil texture.

Genesis and provenance of a new Middle Pleistocene diamicton unit at Happisburgh, NE Norfolk, UK

Glacigenic deposits at Happisburgh, NE Norfolk, record the earliest known expansion of glaciers into lowland eastern England during the Quaternary. The sequence comprises two regionally extensive till units, the Happisburgh Till and Corton Diamicton members of the Happisburgh Glacigenic Formation, deposited during separate ice advances, and intervening glacilacustrine and outwash deposits laid down during ice-marginal retreat. During 2012, a new diamicton unit was discovered within the intervening sorted sediments and its significance is outlined here. Sedimentological and structural evidence suggests, tentatively, that the diamicton forms a small debris fan generated subaerially by a series of water-saturated hyperconcentrated or debris flows. The precise trigger mechanism for these flow deposits remains unclear, but may relate to seasonal melting of surface or buried ice followed by mass-movement, or to more abrupt geological events including periods of intense rainfall, moraine dam failure or a glacier outburst flood.

Influence of Climate Variability on Seasonal Rainfall Patterns in South-Western DR Congo

Climate variability in DR Congo in general and in the Kongo Central Province in particular is well established. However, rains related to variables such as frequency of rainy days and duration of the rainy seasons was generally very little studied. This study aims to investigate the influence of the climate event on rainfall patterns in the south-western of the DRC. This is firstly to characterize the climate event from the analysis of the air temperature, the frequency of rainy days and duration of the rainy seasons. Furthermore compare the normal monthly rainfall over the period 1962- 2012 to clear the behavior of seasonal rainfall patterns. Climate variability is manifested by temporal dynamic regressive temperatures, annual rainfall and a decrease in the number of rainy days. A temperature increase of around 1℃ was observed from 1992 and the thermal peak was recorded in 1994 (>28℃). The highest rainfall was recorded in 2006 (>2400 mm). These variabilities cause short periods of intense rainfall leading to early droughts of the end of season.

The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.

<strong>Diversity of mites associated with <em>Raoiella indica</em> (Acari: Prostigmata) on coconut palms in the central region of the Brazilian Amazonia, with emphasis on the predaceous Phytoseiidae (Acari: Mesostigmata)</strong>

The mite Raoiella indica Hirst (Tenuipalpidae) has caused significant damage to coconut palms in the American continent and in the Caribbean area. Emphasis has been given to the establishment of sustainable measures for the control of this pest in this region, especially the use of predaceous mites. The objective of this study was to determine the occurrence of R. indica and other mites on coconut palms in Manaus (capital of the Amazonas state) and other three neighboring municipalities, at different periods of the year, with emphasis on mites of the family Phytoseiidae. Our hypothesis was that R. indica was not widespread in Manaus region, that it was found at low population levels and in association with a high diversity of predatory mites. Samples were collected at four periods, August/ September 2012 (when rainfall was lower), November/ December 2012 (beginning of the period of intense rainfall), February/ March 2013 (period of intense rainfall) and May/ June 2013 (beginning of the period with lower rainfall). Leaflets, fruits and flowers were sampled from ten plants at each sampling site (one from each municipality) and at each sampling period. Most mites were found on leaflets; 73.9% of these were predominantly phytophagous, 6.1% predominantly predaceous and 20.0% had mainly other feeding habits. Eriophyoidea, tarsonemids and tetranychids were the most abundant groups of predominantly phytophagous mites. Raoiella indica was found at low population levels and in a single site (Iranduba). Phytoseiids were by far the predominant predators (42.5% of the predaceous mites); they were most abundant during intense rainfall. Amblyseius aerialis (Muma), Euseius alatus De Leon and Amblydromalus sp. nov. were the most abundant predators of this family. Cunaxid mites accounted for 27.2% of the predaceous mites. The results of this study suggested that R. indica was not widespread in the region, that it was found at low population levels and that a great diversity of predaceous mites was found on coconut plants in that region. It remains to be seen whether these would be able to maintain the population of that pest under control.

Hydrometeorological Analysis of Tropical Storm Hermine and Central Texas Flash Flooding, September 2010

Abstract Heavy rainfall and flooding associated with Tropical Storm Hermine occurred on 7–8 September 2010 across central Texas, resulting in several flood-related fatalities and extensive property damage. The largest rainfall totals were received near Austin, Texas, and immediately north, with 24-h accumulations at several locations reaching a 500-yr recurrence interval. Among the most heavily impacted drainage basins was the Bull Creek watershed (58 km2) in Austin, where peak flows exceeded 500 m3 s−1. Storm cells were trained over the small watershed for approximately 6 h because of the combination of a quasi-stationary synoptic feature slowing the storm, orographic enhancement from the Balcones Escarpment, and moist air masses from the Gulf of Mexico sustaining the storm. Weather Research and Forecasting Model simulations with and without the Balcones Escarpment terrain indicate that orographic enhancement affected rainfall. The basin received nearly 300 mm of precipitation, with maximum sustained intensities of 50 mm h−1. The Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model was used to simulate streamflow from the event and to analyze the flood hydrology. Model simulations indicate that the spatial organization of the storm during intense rainfall periods coupled with surface conditions and characteristics mediate stream response.

극치강우사상의 시간변동 특성을 고려한 강우시간 분포 개발

본 연구에서는 빈도분석을 이용하여 획득한 확률강우량의 시간분포를 결정할 때 극치강우사상의 시간분포 특성을 반영하는 강우시간 분포 방법을 제시하였다. 극치강우사상에 대하여 강우집중시간과 강우집중시간 동안 발생하는 강우량의 총강우량 대비 비율을 분석하여 설계강우량에 대한 강우시간분포를 구성하였다. 개발된 강우시간분포의 적용성을 검증하기 위하여 서울지점에 대하여 기존의 방법인 Huff 방법과 Yen & Chow 방법 및 SCS방법의 결과와 비교 분석하였다. 일반적인 강우시간분포 방법인 Huff 방법과 Yen & Chow 방법은 극치강우사상의 시간분포 특성을 반영하기에는 너무 평활화하는 한계를 보였다. SCS방법의 경우 강우분포가 지나치게 중앙집중 되는 단점을 보였다. 본 연구에서 제시한 방법에 따른 강우시간분포는 실제 극치강우사상의 시간분포특성을 잘 반영하는 것으로 판단된다. In this study, a new approach to design the time distribution of probable rainfall is suggested to reflect the characteristics of the temporal variability of extreme rainfall events. Time of rainfall concentration and quantile characteristics of the intense rainfall period are analyzed to form the time distribution of designed storms. The developed approach was applied for Seoul to verify its applicability with Huff method, Yen & Chow method, and SCS method. Traditional approaches have limitations that the temporal distributions of rainfall using Huff method and the Yen & Chow method are too smooth to reflect extreme storms. The temporal distributions of rainfall using the SCS method is over concentrated at center. The suggested method demonstrated that it illustrated well of the characteristics of time distribution of extreme rainfall events.

Temperature influences on intense UK hourly precipitation and dependency on large-scale circulation

Short periods of intense rainfall may be associated with significant impacts on society, particularly urban flooding. Climate model projections have suggested an intensification of precipitation under scenarios of climate change. This is in accordance with the hypothesis that precipitation intensities will increase with temperature according to the thermodynamic Clausius–Clapyeron (CC) relation (a rate of ∼6–7% °C−1)—a warmer atmosphere being capable of holding more moisture. Consequently, CC scaling between temperature and extreme precipitation has been demonstrated in numerous studies and in different locations, with higher than CC scaling (so-called super CC scaling) observed for sub-daily extremes. Here we use a new dataset of UK hourly precipitation to identify seasonal scaling relationships between mean daily temperature and 99th percentile hourly precipitation intensities. Pooling the data for the whole UK indicates only slightly higher than CC scaling in spring and summer at higher temperatures, notably less than the 2xCC scaling observed in other regions. Both the highest hourly intensities and the highest scaling in the UK occur in summer and so for this season the dependency of the scaling relationship on large scale circulation conditions is examined using a set of air flow indices. A shear vorticity index (indicative of large-scale flow cyclonicity) is noted to have the greatest influence on the relationship, approaching 2xCC at higher temperatures when shear vorticity is negative (anticyclonic rotation). An examination of the occurrence of intense events indicates that these can occur under cyclonic and anticyclonic conditions but that in the south-east of England the latter conditions disproportionately favour their occurrence. These results suggest that changes in circulation regimes could modify the expected changes in precipitation intensities prescribed by CC scaling and arising as a consequence of future warming.

Characterizing Soil Moisture Memory by Soil Moisture Autocorrelation

Abstract- An autocorrelation value only implies the strength of the soil moisture memory (SMM) without specifying its statistical significance. This study proposed a conversion of autocorrelation values into a time scale considering statistical significance at 95% confidence level. It computed a SMM time scale of 56.13 days for the Spoon river basin, Illinois, and was highly consistent with previous regional estimations (1.8-2.1 months). Additionally, the time scales showed a fair correlation with the 30-day-lagged autocorrelations ( R 2 =0.58). This time scale is easily understandable and provides more information than simple autocorrelations, suggesting significant autocorrelations deal with just a single number. Keywords-Soil Moisture Autocorrelation; Soil Moisture Memory; Soil Moisture Persistence; Soil Moisture Memory Timescale; Xinanjiang Model I. INTRODUCTION Soil moisture isa very important component in weather and climate prediction due to its persistence characteristics [1-8]. Soils can act as a temporary reservoir and hasa tendency to accumulate atmospheric forcing anomalies (deviation from the mean state). For example, an extended period of intense rainfall results ina positive anomaly in the soil moisture state. This anomaly then dissipates through evapotranspiration or runoff. Similarly, any negative anomaly created by a lengthy dry spell is dissipated through rainfall, snowmelt, or irrigation. However, this dissipation process and time scales differ from place to place due to variations in soil properties, scale of interest, and climate forcing.Literature suggests that the complete dissipation process can take hours or months [2, 9]. Therefore, the soil can remember an anomalous condition long after ithas occurred. This phenomenon of memorizing past anomalies is termed “soil moisture persistence” or “soil moisture memory” (hereinafter referred as SMM). The extentof this SMM has potential application in different research fields, primarilyin weather and climate or hydrological predictions. Knowledge of SMM has proven to bean additional toolfor improvingtraditional climate/hydrological forecast efficiency[3, 10]. Advantages of the SMM inclusive approach over traditional forecasts have been reported in several studies. [3, 11] documented the usefulness of SMM understandingto improve soil moisture initialization for weather and climate prediction processes. SMM knowledge can enhance prediction efficiency, mainly in reference to longer time scales and under high initial soil moisture anomaly conditions. Such knowledge mightalso improve the predictability of soil moisture and associated climate [5]. Moreover, soil moisture, through its influence on land energy balance (partitioning sensible and latent heat flux), provides additional feedback on temperature [12, 13] and precipitation [10, 14]. Furthermore, a persistent soil moisture anomaly may prolong the effects of drought [15, 16] and influence the magnitude, occurrence, and receding of floods [17] and streamflow dynamics. Low-frequency streamflow dynamicsare believed to be controlled by the catchment wetness, SMM [18]. Likewise, SMM is believed to be capable of propagating stream flows [19].Currently, streamflow-forecasting efficiency mostly depends on the prediction accuracy of atmospheric forcing or snow accumulation. However, soil moisture conditions evidently affect streamflow forecast accuracy. A dry soil below the snowpack receives and stores infiltrated water from snowmelt and later it evaporates rather than be coming runoff into streams. Conversely,wet soil beneaththe melting snowpack canstimulate streamflow [20]. Therefore, SMMpotentially affects streamflow forecast skills [20, 21]. II.

New insights into debris-flow hazards from an extraordinary event in the Colorado Front Range

Rainfall on 9–13 September 2013 triggered at least 1,138 debris flows in a 3430 km area of the Colorado Front Range. The historical record reveals that the occurrence of these flows over such a large area in the interior of North America is highly unusual. Rainfall that triggered the debris flows began after ~75 mm of antecedent rain had fallen, a relatively low amount compared to other parts of the United States. Most flows were triggered in response to two intense rainfall periods, one 12.5-hour-long period on 11–12 September, and one 8-hour-long period on 12 September. The maximum 10 min. intensities during these periods were 67 and 39 mm/hr. Ninety-five percent of flows initiated in canyons and on hogbacks at elevations lower than a widespread erosion surface of low slope and relief ( 25°), predominantly southand east-facing slopes with upslope contributing areas 3300 m. Areal concentrations of debris flows revealed that colluvial soils formed on sedimentary rocks were more susceptible to flows than soils on crystalline rocks. This event should serve as an alert to government authorities, emergency responders, and residents in the Front Range and other interior continental areas with steep slopes. Widespread debris flows in these areas occur infrequently but may pose a greater risk than in areas with shorter return periods, because the public is typically unprepared for them.

Resistance and resilience: can the abrupt end of extreme drought reverse avifaunal collapse?

AbstractAimClimate change is expected to increase the frequency and intensity of extreme climatic events, such as severe droughts and intense rainfall periods. We explored how the avifauna of a highly modified region responded to a 13‐year drought (the ‘Big Dry’), followed by a two‐year period of substantially higher than average rainfall (the ‘Big Wet’).LocationTemperate woodlands in north central Victoria, Australia.MethodsWe used two spatially extensive, long‐term survey programmes, each of which was repeated three times: early and late in the Big Dry, and in the Big Wet. We compared species‐specific changes in reporting rates between periods in both programmes to explore the resistance (the ability to persist during drought) and resilience (extent of recovery post‐drought) of species to climate extremes.ResultsThere was a substantial decline in the reporting rates of 42–62% (depending on programme) of species between surveys conducted early and late in the Big Dry. In the Big Wet, there was some recovery, with 21–29% of species increasing substantially. However, more than half of species did not recover and 14–27% of species continued to decline in reporting rate compared with early on in the Big Dry. Species' responses were not strongly related to ecological traits. Species resistance to the drought was inversely related to resilience in the Big Wet for 20–35% of the species, while 76–78% of species with low resistance showed an overall decline across the study period.ConclusionsAs declines occurred largely irrespective of ecological traits, this suggests a widespread mechanism is responsible. Species that declined the most during the Big Dry did not necessarily show the greatest recoveries. In already much modified regions, climate extremes such as extended drought will induce on‐going changes in the biota.

Experimental Testing for the Analysis of a Landslide Phenomenon Produced in a Hillside Area from Romania

The landslide that is the subject of this paper occurred in the central part of Romania, in Prahova County, located near the Prahova Valley, in hillside area, frequently affected by this kind of major hazard. The geological phenomenon occurred in the area is an old event and it was reactivated starting with 2010. The inappropriate geological and geotechnical conditions characteristic of the area and also the lack of a drainage system were conducted to landslide reactivation during a period of intense rainfall. The present work was carried out to study the spatial influence of geological and morphological factors upon landslide occurrence on a local scale by using geotechnical and geophysical methods in order to determine local trigger parameters. The complex studies were conducted in finding the most feasible technical and economical option for the efficient emergency management of landslide hazard.

New Method for Estimating Landslide Losses from Major Winter Storms in California and Application to the ARkStorm Scenario

AbstractARkStorm is a statewide emergency planning scenario hypothesizing severe atmospheric river storms that transport huge amounts of moisture from the tropical Pacific to California, where it falls as intense rain. The storm is projected to be similar to historic storms that have struck California in recent decades, but include extended periods of intense rainfall that approach the massive storms of 1861–1862 in total rainfall. A meteorological model for the ARkStorm has been developed from records of the 1969 and 1986 storms, both of which caused widespread landslides and severe damage in California. Estimating the numbers and impact of landslides from the ARkStorm requires models relating rainfall to the number and distribution of landslides and detailed records of the impact of landslides in past storms. Neither of these basic data sets exist. However, models that estimate the areas with the greatest susceptibility to landsliding do exist and can be combined with detailed maps of small areas showin...

Towards hydrological and geochemical understanding of an ephemeral palustrine perched water table “wetland” (Lanseria Gneiss, Midrand, South Africa)

Wetland delineation is commonly based on terrain unit, soil form, soil wetness and vegetation indicators which along with the shallow groundwater or proximate surface water are often absent in many ephemeral inland South African areas due to, for instance, prolonged dry periods (seasons to years) which mask these indicators, as well as disruption of surface materials due to construction, agricultural activities and field fires. Furthermore, many “wetlands” in South Africa comply with the four indicators, but the notable absent requirement for wetlands is missing, namely the shallow groundwater table, as many of these systems form in hillslope seeps, catenas or from perched water tables. A 200-m-long excavation through one such a system is being studied in Midrand (Gauteng, South Africa). The site is underlain by Lanseria Gneiss and is waterlogged after long and intense periods of intense rainfall. Frequent downslope soil profiling, horizon-specific laboratory analyses for grading and Atterberg Limits, X-Ray Diffraction and X-Ray Fluorescence Spectroscopy data are interpreted together with soil percolation tests to generate a conceptual model of the system. The results are discussed in terms of the need to consider these temporary systems that do not have a shallow groundwater table and that are not in direct contact with surface drainage features as a possible special type of wetlands, notably in arid regions where they play a very important role in biodiversity and should, therefore, be protected.

Comparison study between traditional and finite element methods for slopes under heavy rainfall

In this paper, a comparison study has been carried out between the limit equilibrium (conventional) methods and finite element method of estimation factor of safety of slopes under the effect of rainfall. A case study is analyzed with the finite element method, and the results are compared with outcomes from some of the well-known conventional methods namely: simplified Bishop Method (1955), simplified Janbu method (1954), and Fellenius method (1927).Moreover, slope stability concerning rainfall and infiltration is analyzed. Specially, two kinds of infiltrations (saturated and unsaturated) are considered. Many slopes become saturated during periods of intense rainfall or snowmelt, with the water table rising to the ground surface, and water flowing essentially parallel to the direction of the “slope” and “Influence” of the change in shear strength, density, pore-water pressure and seepage force in soil slices on the slope stability is explained. Finally, it is found that classical limit equilibrium methods are highly conservative compared to the finite element approach. For assessment the factor of safety for slope using the later technique, no assumption needs to be made in advance about the shape or location of the failure surface, slice side forces and their directions. This document outlines the capabilities of the finite element method in the analysis of slope stability problems.

Cut slopes failures on the Triassic beds in Coimbra, Portugal

An analysis is presented of several cut slope failures which occurred in the Triassic “Gres de Silves”, in the area of Areeiro in Coimbra, Portugal. They developed along thin mudstone layers dipping at some 16° towards the face of the excavation. The failures mainly occurred after periods of intense rainfall, sometimes immediately after the excavation of the slope, and in some cases have continued for the 7 years since, even where the slope height was only a few metres. The conditions leading to the failures were investigated in the field and in the laboratory. It was concluded that the main factors inducing the slope failure are a conjugation of the geological structure and the reduction in the shear strength of the mudstones when they dilate following excavation. This dilation allows the ingress of water further reducing the shear strength of the mudstones.

Comparative analysis of the response of various land covers to an exceptional rainfall event in the central Spanish Pyrenees, October 2012

ABSTRACTThe hydrological and geomorphological effects of an exceptional rainstorm event that occurred in the central Spanish Pyrenees during 19–21 October 2012 were studied in five experimental catchments under various land covers: (i) subhumid badlands; (ii) dense forest; (iii) an abandoned farmland area recolonized by shrubs and forest patches; and (iv) subalpine grasslands. Hydrographs and sedigraphs demonstrated that vegetation cover is a major factor affecting the control of floods even during exceptional rainstorms, at least at the spatial scale at which the phenomenon was studied (catchment sizes: 0.3–2.8 km2) and under dry catchment conditions. The combined precipitation over the two days (c. 250 mm) was the greatest for any two‐day event recorded since 1950 in the central‐western Pyrenees for all but one of the stations in the study. Five pulses of most intense rainfall were recorded. The forested catchment did not react to the two most intense rainfall pulses, because of the very low antecedent level of the water table. The main peak flow occurred only when at least a part of the catchment was saturated. The abandoned farmland catchment had two small peak discharges at the beginning of the event, which were produced by infiltration excess overland flow from eroded areas close to the main stream. During the third most intense rainfall period a large part of this catchment contributed to runoff and a relatively high peak discharge was produced. The badland catchment reacted immediately from the beginning of the rainstorm, yielding very high discharges accompanied by high suspended sediment concentrations. The subalpine catchment showed a hydrograph mirroring the hyetograph, with brief but intense hydrological responses to increased precipitation, because of the marked gradients and the presence of bare rock in the headwaters. A high volume of bedload was carried during the peak discharge. Copyright © 2013 John Wiley & Sons, Ltd.

Hydropedology and Ecohydrology of the Brigalow Belt, Australia: Opportunities for Ecosystem Rehabilitation in Semiarid Environments

The Brigalow Belt Bioregion—located between the subtropical coastline and semiarid interior of eastern Australia—is a unique ecological area characterized by noncracking clay soils that have high water‐holding capacities, and rainfall patterns that are spatiotemporally erratic and unpredictable. These attributes have resulted in highly variable water‐supply conditions defined by alternating periods of intense rainfall and prolonged drought to which open‐forests and woodlands dominated by endemic Brigalow (Acacia harpophylla F. Muell. ex Benth.) plant communities are best adapted. Since the 1950s, most of the Brigalow woodland has been cleared for agriculture and now coal mining developments, therefore very little of the predisturbance vegetation today remains. The primary goal of landscape rehabilitation currently targets the re‐establishment of native Brigalow plant communities in hopes of achieving stable and self‐sustaining ecosystems. However, very few reference ecosystems exist from which to determine essential ecological structure and function. Therefore, restoration practitioners are faced with the daunting task of reconstructing landforms and ecosystems that are characteristic of the bioregion's distinct environmental conditions. Here, we examine the fundamental hydropedological and ecohydrological relationships that define the function of natural Brigalow ecosystems. We propose these relationships as the cornerstone for rehabilitation of semiarid environments and suggest applying investigative methods of related disciplines within a unifying modeling framework (gray‐box) to promote the development of native plants in the Brigalow Belt. This is particularly critical where model parameterization may span a broad ecological organizational scale or where there are knowledge gaps within the model framework.

Suitability of Eastern Gamagrass for In Situ Precipitation Catchment Forage Production in Playas

Freshwater playas, shallow ephemeral lakes whose basins fill after periods of prolonged or intense rainfall, occupy 3 to 5% of the land in the Llano Estacado and are considered marginal farmlands. The goals of this work were to determine if a native species, eastern gamagrass, could be grown on playa soils and to preliminarily evaluate the suitability of gamagrass [Tripsacum dactyloides (L.) L.] as a component of an in situ precipitation catchment forage production system. Flooding tolerance of gamagrass seeds was evaluated, and plants were grown on playa soil in both the greenhouse and field for several seasons. Gamagrass seed was resistant to extended flooding, especially at low ambient temperatures typically encountered in late fall or winter. Gamagrass roots penetrated nearly 2 m into waterlogged playa soil in greenhouse experiments. Stands were successfully established in playas, and plants survived for 6 yr when crowns were not destroyed by close mowing or vehicles. Eastern gamagrass is a viable candidate species that might be used as part of a novel playa‐based forage production system.