Changes in Antecedent Soil Moisture Modulate Flood Seasonality in a Changing Climate

India is severely affected by tropical cyclones (TC) each year, which generates intense rainfall and strong winds leading to flooding. Most of the TC induced floods have been attributed to heavy rain associated with them. Here we show that both rainfall and elevated antecedent soil moisture due to temporally compounding tropical cyclones cause floods in the major Indian basins. We assess each basin's response to observed TC events from 1980 to 2019 using the Variable Infiltration Capacity (VIC) model. The VIC model was calibrated (R2 > 0.5) and evaluated against observed hourly streamflow for major river basins in India. We find that rainfall due to TC does not result in floods in the basin, even for rainfall intensities similar to the monsoon period. However, TCs produce floods in the basins, when antecedent soil moisture was high. Our findings have implications for the understanding of TC induced floods, which is crucial for disaster mitigation and management.

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Preliminary investigation of emerging suburban landsliding in Gisborne, New Zealand

Quarterly Journal of Engineering Geology and Hydrogeology ◽

10.1144/qjegh2021-087 ◽

2022 ◽

pp. qjegh2021-087

Author(s):

Matthew E. Cook ◽

Martin S. Brook ◽

Jon Tunnicliffe ◽

Murry Cave ◽

Noah P. Gulick

Keyword(s):

Soil Moisture ◽

New Zealand ◽

High Intensity ◽

Preliminary Investigation ◽

Rainfall Event ◽

Slope Instability ◽

Antecedent Soil Moisture ◽

Field Surveys ◽

Coastal City ◽

The North

Recently uplifted, soft Pleistocene sediments in northern New Zealand are particularly vulnerable to landsliding because they are often underlain by less permeable, clay-rich Neogene mudstone/siltstone rocks. Typically, instability is rainfall-induced, often due to a high intensity rainfall event from extra-tropical cyclones, following wetter months when antecedent soil moisture has increased. Using remote sensing, field surveys and laboratory testing, we report on some emerging slope instability hazards in the eastern suburbs of the coastal city of Gisborne, on the North Island. Retrogressive failure of the main landslide (at Wallis Road) is ongoing and has already led to the abandonment of one home, while an adjacent landslide (at Titirangi Drive) appears to be in an incipient phase of failure. The Wallis Road landslide has been particularly active from mid-2017, with slumping of the headscarp area transitioning to a constrained mudflow downslope, which then descends a cliff before terminating on the beach. In contrast, the incipient Titirangi Drive landslide at present displays much more subtle effects of deformation. While activity at both landslides appears to be linked to rainfall-induced increases in soil moisture, this is due to the effects of prolonged periods of rainfall rather than the passage of high intensity cyclonic storms.

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The temporally varying roles of rainfall, snowmelt and soil moisture for debris flow initiation in a snow-dominated system

Hydrology and Earth System Sciences ◽

10.5194/hess-22-3493-2018 ◽

2018 ◽

Vol 22 (6) ◽

pp. 3493-3513 ◽

Cited By ~ 10

Author(s):

Karin Mostbauer ◽

Roland Kaitna ◽

David Prenner ◽

Markus Hrachowitz

Keyword(s):

Soil Moisture ◽

Debris Flow ◽

High Intensity ◽

Debris Flows ◽

Regional Scale ◽

Early Summer ◽

Temporal Separation ◽

Antecedent Soil Moisture ◽

Trigger Mechanisms ◽

Debris Flow Initiation

Abstract. Debris flows represent frequent hazards in mountain regions. Though significant effort has been made to predict such events, the trigger conditions as well as the hydrologic disposition of a watershed at the time of debris flow occurrence are not well understood. Traditional intensity-duration threshold techniques to establish trigger conditions generally do not account for distinct influences of rainfall, snowmelt, and antecedent moisture. To improve our knowledge on the connection between debris flow initiation and the hydrologic system at a regional scale, this study explores the use of a semi-distributed conceptual rainfall–runoff model, linking different system variables such as soil moisture, snowmelt, or runoff with documented debris flow events in the inner Pitztal watershed, Austria. The model was run on a daily basis between 1953 and 2012. Analysing a range of modelled system state and flux variables at days on which debris flows occurred, three distinct dominant trigger mechanisms could be clearly identified. While the results suggest that for 68 % (17 out of 25) of the observed debris flow events during the study period high-intensity rainfall was the dominant trigger, snowmelt was identified as the dominant trigger for 24 % (6 out of 25) of the observed debris flow events. In addition, 8 % (2 out of 25) of the debris flow events could be attributed to the combined effects of low-intensity, long-lasting rainfall and transient storage of this water, causing elevated antecedent soil moisture conditions. The results also suggest a relatively clear temporal separation between the distinct trigger mechanisms, with high-intensity rainfall as a trigger being limited to mid- and late summer. The dominant trigger in late spring/early summer is snowmelt. Based on the discrimination between different modelled system states and fluxes and, more specifically, their temporally varying importance relative to each other, this exploratory study demonstrates that already the use of a relatively simple hydrological model can prove useful to gain some more insight into the importance of distinct debris flow trigger mechanisms. This highlights in particular the relevance of snowmelt contributions and the switch between mechanisms during early to mid-summer in snow-dominated systems.

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Do small and large floods have the same drivers of change? A regional attribution analysis in Europe

10.5194/hess-2020-396 ◽

2020 ◽

Author(s):

Miriam Bertola ◽

Alberto Viglione ◽

Sergiy Vorogushyn ◽

David Lun ◽

Bruno Merz ◽

...

Keyword(s):

Soil Moisture ◽

Return Period ◽

Extreme Precipitation ◽

Gumbel Distribution ◽

Secondary Importance ◽

Antecedent Soil Moisture ◽

Covariate Data ◽

Study Results ◽

Flood Quantiles ◽

Flood Peaks

Abstract. Recent studies have shown evidence of increasing and decreasing trends in mean annual floods and flood quantiles across Europe. Studies attributing observed changes in flood peaks to their drivers have mostly focused on mean annual floods. This paper proposes a new framework for attributing flood changes to potential drivers, as a function of return period (T), in a regional context. We assume flood peaks to follow a non-stationary regional Gumbel distribution, where the median flood and the 100-year growth factor are used as parameters. They are allowed to vary in time and between catchments as a function of the drivers quantified by covariates. The elasticities of floods with respect to the drivers and the contributions of the drivers to flood changes are estimated by Bayesian inference. The prior distributions of the elasticities of flood quantiles to the drivers are estimated by hydrological reasoning and from the literature. The attribution model is applied to European flood and covariate data and aims at attributing the observed flood trend patterns to specific drivers for different return periods. We analyse flood discharge records from 2370 hydrometric stations in Europe over the period 1960–2010. Extreme precipitation, antecedent soil moisture and snowmelt are the potential drivers of flood change considered in this study. Results show that, in northwestern Europe, extreme precipitation mainly contributes to changes in both the median (q2) and 100-year flood (q100), while the contributions of antecedent soil moisture are of secondary importance. In southern Europe, both antecedent soil moisture and extreme precipitation contribute to flood changes, and their relative importance depends on the return period. Antecedent soil moisture is the main contributor to changes in q2, while the contributions of the two drivers to changes in larger floods (T > 10 years) are comparable. In eastern Europe, snowmelt drives changes in both q2 and q100.

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Concurrent and antecedent soil moisture relate positively or negatively to probability of large wildfires depending on season

International Journal of Wildland Fire ◽

10.1071/wf15104 ◽

2016 ◽

Vol 25 (6) ◽

pp. 657 ◽

Cited By ~ 20

Author(s):

Erik S. Krueger ◽

Tyson E. Ochsner ◽

J. D. Carlson ◽

David M. Engle ◽

Dirac Twidwell ◽

...

Keyword(s):

Soil Moisture ◽

Growing Season ◽

Fuel Moisture ◽

Fuel Production ◽

Antecedent Soil Moisture ◽

Plant Water Stress ◽

Wildfire Occurrence ◽

Water Capacity ◽

Available Water Capacity ◽

Dormant Season

Measured soil moisture data may improve wildfire probability assessments because soil moisture is physically linked to fuel production and live fuel moisture, yet models characterising soil moisture–wildfire relationships have not been developed. We therefore described the relationships between measured soil moisture (concurrent and antecedent), as fraction of available water capacity (FAW), and large (≥405 ha) wildfire occurrence during the growing (May–October) and dormant (November–April) seasons from 2000 to 2012 in Oklahoma, USA. Wildfires were predominantly grass and brush fires but occurred across multiple fuel types including forests. Below-average FAW coincided with high wildfire occurrence each season. Wildfire probability during the growing season was 0.18 when concurrent FAW was 0.5 (a threshold for plant water stress) but was 0.60 when concurrent FAW was 0.2 (extreme drought). Dormant season wildfire probability was influenced not only by concurrent but also by antecedent FAW. Dormant season wildfire probability was 0.29 and 0.09 when FAW during the previous growing season was 0.9 (near ideal for plant growth) and 0.2, respectively. Therefore, although a wet growing season coincided with reduced wildfire probability that season, it also coincided with increased wildfire probability the following dormant season, suggesting that the mechanisms by which soil moisture influences wildfire probability are seasonally dependent.

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Data-based attribution of changes in flood quantiles across Europe between 1960 and 2010

10.5194/egusphere-egu21-2604 ◽

2021 ◽

Author(s):

Miriam Bertola ◽

Alberto Viglione ◽

Sergiy Vorogushyn ◽

David Lun ◽

Bruno Merz ◽

...

Keyword(s):

Soil Moisture ◽

Return Period ◽

Extreme Precipitation ◽

Western Europe ◽

Expert Knowledge ◽

Flood Frequency ◽

Antecedent Soil Moisture ◽

Flood Quantiles ◽

Comparable Magnitude ◽

Large Floods

Changes in European floods during past decades have been analysed and detected by several studies. These studies typically focused on the mean flood behaviour, without distinguishing small and large floods. In this work, we investigate the causes of the detected flood trends across Europe over five decades (1960-2010), as a function of the return period. We adopt a regional non-stationary flood frequency approach to attribute observed flood changes to potential drivers, used as covariates of the parameters of the regional probability distribution of floods. The elasticities of floods with respect to the drivers and the regional contributions of the drivers to changes in flood quantiles associated with small and large return periods (i.e. 2-year and 100-year floods, respectively) are estimated by Bayesian inference, with prior information on the elasticity parameters obtained from expert knowledge and the literature. The data-based attribution approach is applied to annual maximum flood discharge seires from 2370 hydrometric stations in Europe. Extreme precipitation, antecedent soil moisture and snowmelt are the potential drivers considered. Results show that extreme precipitation mainly contributes to positive flood changes in North-western Europe. Both antecedent soil moisture and extreme precipitation contribute to negative flood changes in Southern Europe, with relative contributions varying with the return period. Antecedent soil moisture contributes the most to changes in small floods (i.e. T=2-10 years), while the two drivers contribute with comparable magnitude to changes in more extreme events. In eastern Europe, snowmelt clearly drives negative changes in both small and large floods.

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Dominant drivers of runoff in a slash-and-burn affected catchment in upland Eastern Madagascar

10.5194/egusphere-egu21-3957 ◽

2021 ◽

Author(s):

Bob W. Zwartendijk ◽

H.J. (Ilja) van Meerveld ◽

Ryan J. Teuling ◽

Chandra P. Ghimire ◽

L. Adrian Bruijnzeel

Keyword(s):

Soil Moisture ◽

Overland Flow ◽

Quantitative Information ◽

Forest Loss ◽

Runoff Generation ◽

Catchment Scale ◽

Valley Bottom ◽

Antecedent Soil Moisture ◽

Slash And Burn ◽

Slash And Burn Agriculture

In many tropical areas slash-and-burn agriculture is an important driver of forest loss. In areas where slash-and-burn agriculture has been practiced for decades, land cover is typically a mosaic of patches of remnant forest, fields under active cultivation, fallows in various stages of regrowth (ranging from young shrub to semi-mature), and degraded fire-climax grasslands. Although runoff generation mechanisms are expected to be different for these different patches, little quantitative information is available in this regard, particularly at the catchment scale and over longer time-scales (i.e., multiple slash-and-burn cycles).We re-instrumented a 31&#160;ha catchment in upland Eastern Madagascar, where slash-and-burn agriculture has been practiced for more than 70&#160;years in 2015; it had been monitored between 1963 and 1972 as well1. We measured streamflow at two locations and overland flow and soil moisture for four hillside plots (0.05 &#8211; 1.93&#160;ha): one plot under repeatedly coppiced and burned Eucalyptus and three plots under young shrub and tree fallows. One of the plots underwent rudimentary terracing in the past. We analysed the rainfall-runoff dynamics for 50&#160;rainfall events (median 12&#160;mm, maximum 71&#160;mm).For 60% of the events, the stormflow coefficient (minimum contributing area) was <3%, which is the proportion of valley-bottom wetlands and rice paddies in the catchment. Stable isotope sampling for five storm runoff events indicate a maximum total event-water contribution of 16%. However, instantaneous event-water contributions were as high as 66%. The hillside plot runoff response was dominated by saturation-excess overland flow and showed strong threshold behaviour in terms of the antecedent soil moisture storage in the upper 30 cm of the soil plus the event total rainfall amount (ASI + P). Average threshold values for overland flow occurrence ranged from 87 mm for the coppiced Eucalyptus to 137&#160;mm for the young fallow plots (regardless of terrace presence). Stormflow also increased after an ASI+P-threshold was exceeded (100&#160;mm based on the soil moisture sensors for the Eucalyptus plot and 150&#160;mm for the sensors at the tree fallow plots).These results indicate an increased hydrological connectivity between hillslopes and valley bottom under wetter conditions and that stormflow in the study catchment is strongly affected by variations in seasonal rainfall. The results will be used to validate a hydrological model to determine the net effect of concurrent changes in soil infiltrability and vegetation water use associated with forest loss and recovery on stormflow totals and the seasonal flow regime.1Bailly, C., de Coignac, G.B., Malvos, C., Ningre, J.M., and Sarrailh, J.M. (1974). &#201;tude de l'influence du couvert naturel et de ses modifications &#225; Madagascar. Exp&#233;rimentations en bassins versants &#233;l&#233;mentaires. Cahiers Scientifiques, 4. Centre Scientifique Forestier Tropical, Nogent-sur-Marne, France, 114 pp.

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Impacts of Antecedent Soil moisture on the Rainfall–Runoff Transformation Process Based on High-Resolution Observations in Soil Tank Experiments

Water ◽

10.3390/w11020296 ◽

2019 ◽

Vol 11 (2) ◽

pp. 296 ◽

Cited By ~ 5

Author(s):

Shuang Song ◽

Wen Wang

Keyword(s):

Soil Moisture ◽

Overland Flow ◽

Response Times ◽

Hysteretic Behavior ◽

Rainfall Runoff ◽

Moisture Index ◽

Antecedent Soil Moisture ◽

Non Linear ◽

Subsurface Runoff ◽

The Impact

An experimental soil tank (12 m long × 1.5 m wide × 1.5m deep) equipped with a spatially distributed instrument network was designed to conduct the artificial rainfall–runoff experiments. Soil moisture (SM), precipitation, surface runoff (SR) and subsurface runoff (SSR) were continuously monitored. A total of 32 rainfall–runoff events were analyzed to investigate the non-linear patterns of rainfall–runoff response and estimate the impact of antecedent soil moisture (ASM) on runoff formation. Results suggested that ASM had a significant impact on runoff at this plot scale, and a moisture threshold-like value which was close to field capacity existed in the relationship between soil water content and event-based runoff coefficient (φe), SSR and SSR/SR. A non-linear relationship between antecedent soil moisture index (ASI) that represented the initial storage capacity of the soil tank and total runoff was also observed. Response times of SR and SM to rainfall showed a marked variability under different conditions. Under wet conditions, SM at 10 cm started to increase prior to SR on average, whereas it responds slower than SR under dry conditions due to the effect of water repellency. The predominant contributor to SR generation for all events is the Hortonian overland flow (HOF). There is a hysteretic behavior between subsurface runoff flow and soil moisture with a switch in the hysteretic loop direction based on the wetness conditions prior to the event.

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Salmonella Survival in Soil and Transfer Onto Produce via Splash Events

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-066 ◽

2019 ◽

Vol 82 (12) ◽

pp. 2023-2037 ◽

Cited By ~ 2

Author(s):

DEBBIE LEE ◽

MOUKARAM TERTULIANO ◽

CASEY HARRIS ◽

GEORGE VELLIDIS ◽

KAREN LEVY ◽

...

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Moisture Content ◽

Geometric Mean ◽

The United States ◽

Mean Difference ◽

Antecedent Soil Moisture ◽

Produce Safety ◽

Produce Contamination ◽

Salmonella Survival

ABSTRACT Nearly one-half of foodborne illnesses in the United States can be attributed to fresh produce consumption. The preharvest stage of production presents a critical opportunity to prevent produce contamination in the field from contaminating postharvest operations and exposing consumers to foodborne pathogens. One produce-contamination route that is not often explored is the transfer of pathogens in the soil to edible portions of crops via splash water. We report here on the results from multiple field and microcosm experiments examining the potential for Salmonella contamination of produce crops via splash water, and the effect of soil moisture content on Salmonella survival in soil and concentration in splash water. In field and microcosm experiments, we detected Salmonella for up to 8 to 10 days after inoculation in soil and on produce. Salmonella and suspended solids were detected in splash water at heights of up to 80 cm from the soil surface. Soil-moisture conditions before the splash event influenced the detection of Salmonella on crops after the splash events—Salmonella concentrations on produce after rainfall were significantly higher in wet plots than in dry plots (geometric mean difference = 0.43 CFU/g; P = 0.03). Similarly, concentrations of Salmonella in splash water in wet plots trended higher than concentrations from dry plots (geometric mean difference = 0.67 CFU/100 mL; P = 0.04). These results indicate that splash transfer of Salmonella from soil onto crops can occur and that antecedent soil-moisture content may mediate the efficiency of microbial transfer. Splash transfer of Salmonella may, therefore, pose a hazard to produce safety. The potential for the risk of splash should be further explored in agricultural regions in which Salmonella and other pathogens are present in soil. These results will help inform the assessment of produce safety risk and the development of management practices for the mitigation of produce contamination. HIGHLIGHTS

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