Navigating through Sources

Consciousness and the Novel: Connected Essays by the famous British novelist David Lodge is a classic work published by Harvard in 2004.

In this Lodge book, the author mentions a famous British society-watcher, Charles Masterman. In 1909, Masterman published his best-known study, The Condition of England, which tells us that England at that time experienced a greater inflow of migrants into London than in previous centuries taken together.

[Charles Frederick Gurney Masterman PC MP (24 October 1873 – 17 November 1927) was a British radical Liberal Party politician, intellectual and man of letters. He worked closely with such Liberal leaders as David Lloyd George and Winston Churchill in designing social welfare projects, including the National Insurance Act 1911. During the First World War, he played a central role in the main government propaganda agency.]

We then notice that one recurrent topic in various movie versions of the E. M. Forster novel Howards End (1910, set in those years) is the “horrifying” trend where great mansions and stately estates (Howards End and Wickham Place, say, in the novel) are all being demolished and replaced by ugly “flats.”

There must be, one thinks, a direct link between all the massive migrations into London at the time and all the proliferating flats at the “expense” of beautiful and historical villas. (This “demolish” trend is also part of the story of the classic novel A Handful of Dust by Evelyn Waugh, 1934)

In the predecessor to Downton Abbey called Upstairs, Downstairs, the story ends in 1930 with a sign outside the great “house” at Eaton Place offering flats coming soon, as the demand for housing (think of San Francisco today) is so massive that sellers can make a fortune selling out to developers, move into one of the flats being created, and live off the sale for the rest of their lives and “duck” the higher “Lloyd George taxes.” (In Downton Abbey, the dowager played by Maggie Smith repeatedly lashes out at Prime Minister Lloyd George as a kind of financial traitor.)

We see from this simple example how students should learn to “jump” between books and movies and TV miniseries to get a stronger focus on what’s being depicted on screens and pages and not just “swim along” at the surface level without any “drilling down.”

Education is largely the struggle or habit where students learn to bring pattern and structure out of “chaos,” thus giving narratives some overall shape.

This reminds one of the opening lines of Beryl Markham’s 1942 Africa memoir:

“How is it possible to bring order out of memory? I should like to begin at the beginning, patiently, like a weaver at his loom. I should like to say, ‘This is the place to start; there can be no other.’ ”

from West with the Night by Beryl Markham

This is a similar impetus: to bring order out of memory or others’ memories in books and movies from various times and places.

Movies as a Parallel University: The Case of Romantic Imperialism

When we think of romantic imperialism, we think of Rudyard Kipling’s poems, Winston Churchill’s The River War and perhaps Teddy Roosevelt’s macho “strenuous life” romanticized militarism (which the neocons somewhat knowingly aped to get the U.S. to invade Iraq in 2003). We should also recall British movie classics like The Four Feathers and “deflationary” versions of these jingoistic notions in The Man Who Would be King. During the 1930s, the Hungarian brothers Alexander & Zoltan Korda created many classic empire-celebration films in London, such as 1935’s Sanders of the River.

The Nigerian writer Chinua Achebe’s attack on Joseph Conrad’s Heart of Darkness as a kind of toxic “othering” of all Africans is a culmination of these imperial and anti-imperial tendencies.

Lastly, Maupassant’s classic Bel-Ami represents Algeria as a “colonial badlands” for French domination, killing, despoiling, profiteering, and later culminates in Meursault’s random murder of an Arab again in Algeria in Camus’ classic The Stranger. This literary concatenation also fits into this set of colonial imperial phenomena.

Niall Ferguson (the famous Harvard/Stanfordempire enthusiast”) finds his forerunner in the 1940 classic movie Beyond Tomorrow. The following “row” takes place on Christmas Eve between Chadwick (the Niall Ferguson imperialist) and Melton who sees empire as land-grabbing which you can dress up and prettify any way you like (“a grab is a grab,” he says):

Allan Chadwick: I tell you England’s territorial expansion had quite a different significance.

George Melton: No matter how thin you slice it, a grab is a grab.

Allan Chadwick: Grab?

That’s a specious term. England carried civilization into the wilderness. What was Australia before she redeemed it from the Aborigines?

Allan Chadwick: The truth is there isn’t an acre of the Empire that isn’t proud to fly the British flag.

The quick irritated exchange from Beyond Tomorrow is a good example of this eternal argument, allowing you to then “jump off” from this movie-as-university to do more exploring.

Precursors of Trumpism in American Culture: The Great Gatsby

Donald Trump’s brand of “nativist populism” is prefigured very clearly in the 1925 classic American novel The Great Gatsby by F. Scott Fitzgerald, the subject of several film adaptations. The anxiety in the Trump movement is called “The Great Replacement” (i.e., white people supplanted by minoritiesAmerican non-whites will “link up” with Mexicans and Chinese, stealing the place, property and role of white people). It has never occurred to these people that most of the world’s population is non-white. In The Great Gatsby, Tom Buchanan, Daisy’s husband, represents this anxiety.

He links these fears to the anxiety that “the sun is getting hotter.” (That is, he’s being threatened cosmically too, not only by racial demography.) His fears are not of “climate change,” based on something rational, but obsessive and maniacal “threat assessments.” They mirror the “irrational clusters of threats” of Trump and his voters, who “want to be paid in advance forever for their being white, Christian and American.” They demand “racial tenure.” This Tom Buchanan syndrome may be considered a type of “globalization backlash.”

Tom Buchanan lays it out in the novel:

“Civilization’s going to pieces,” broke out Tom violently. “I’ve gotten to be a terrible pessimist about things. Have you read The Rise of the Colored Empires by this man Goddard?…Well, it’s a fine book, and everybody ought to read it. The idea is if we don’t look out the white race will be — will be utterly submerged. It’s all scientific stuff; it’s been proved…This fellow has worked out the whole thing. It’s up to us, who are the dominant race, to watch out or those other races will have control of things…The idea is that we’re Nordics. I am, and you are, and we’ve produced all the things that go to make civilization—oh, science and art, and all that. Do you see?”

(The Great Gatsby, Chapter 1)

“…Nowadays people begin by sneering at family life and family institutions, and next they’ll throw everything overboard and have marriage between black and white.”

Flushed with his impassioned gibberish, he saw himself standing alone on the last barrier of civilization.

“We’re all white here,” murmured Jordan.

Angry as I was, as we all were, I was tempted to laugh whenever he opened his mouth. The transition from libertine to prig was so complete.

(The Great Gatsby, Chapter 7)

The Brexit phenomenon in the United Kingdom is not identical but does overlap (i.e., the “left behind” people in England want “historical ethnic-national tenure” and a kind of re-segregation).

Education: Disease, History and Lit

The Italian writer Giovanni Boccaccio lived through the plague as it ravaged the city of Florence in 1348. The experience inspired him to write The Decameron.

The Plague of 1665 in England was a major upheaval affecting Isaac Newton’s life.

The 1984 movie, A Passage to India (David Lean) set in 1920s India, has a scene where the ever-present lethal threat of cholera is discussed as Doctor Aziz lies sick of a fever.

The W. Somerset Maugham novel, The Painted Veil (2006 movie) is also about cholera in the Chinese countryside in the 1920s.

Manzoni’s 1827 The Betrothed, the most famous classic novel of Italian literature, centers on the plague to drive the story.

Overview:

Etymologically, the term “pest” derives from the Latin word “pestis” (pest, plague, curse). Hardly any disease had such cultural and historical relevance as the bubonic plague. Throughout the centuries, the plague was the most terrifying infectious contagious disease which generated a series of demographic crises. The plague epidemics influenced the evolution of society biologically and culturally speaking. The Black Death was one of the most devastating pandemics in human history, is estimated to have killed 30%–60% of Europe’s population, reducing the world’s population from an estimated 450 million to between 350 and 375 million in 1400. This has been seen as having created a series of religious, social and economic upheavals, which had profound effects on the course of European history. It took 150 years for Europe’s population to recover.

The plague returned at various times, killing more people, until it left Europe in the 19th century. Modern epidemiology (Dr. John Snow, London) has its roots in cholera management and water sanitation as well as waste management.

Education involves seeing disease as a major protagonist in all history and not as a footnote.

The classic Plagues and Peoples should accordingly be studied by every student: Plagues and Peoples is a book on epidemiological history by William Hardy McNeill, published in 1976.

It was a critical and popular success, offering a radically new interpretation of the extraordinary impact of infectious disease on cultures and world history itself.

Essay 108: Early View Alert: Water Resources Research

from the American Geophysical Union’s journals:

Research Articles

Modeling the Snow Depth Variability with a High-Resolution Lidar Data Set and Nonlinear Terrain Dependency

by T. Skaugen & K. Melvold

Summary: Using airborne laser, 400 million snow depth measurements at Hardangervidda in Southern Norway have been collected. The amount of data has made in-depth studies of the spatial distribution of snow and its interaction with the terrain and vegetation possible. We find that the terrain variability, expressed by the square slope, the average amount of snow, and whether the terrain is vegetated or not, largely explains the variation of snow depth. With this information it is possible to develop equations that predict snow depth variability that can be used in environmental models, which again are used for important tasks such as flood forecasting and hydropower planning. One major advantage is that these equations can be determined from the data that are, in principle, available everywhere, provided there exists a detailed digital model of the terrain.

[Archived PDF article]

Phosphorus Transport in Intensively Managed Watersheds

by Christine L. Dolph, Evelyn Boardman, Mohammad Danesh-Yazdi, Jacques C. Finlay, Amy T. Hansen, Anna C. Baker & Brent Dalzell

Abstract: When phosphorus from farm fertilizer, eroded soil, and septic waste enters our water, it leads to problems like toxic algae blooms, fish kills, and contaminated drinking supplies. In this study, we examine how phosphorus travels through streams and rivers of farmed areas. In the past, soil lost from farm fields was considered the biggest contributor to phosphorus pollution in agricultural areas, but our study shows that phosphorus originating from fertilizer stores in the soil and from crop residue, as well as from soil eroded from sensitive ravines and bluffs, contributes strongly to the total amount of phosphorus pollution in agricultural rivers. We also found that most phosphorus leaves farmed watersheds during the very highest river flows. Increased frequency of large storms due to climate chaos will therefore likely worsen water quality in areas that are heavily loaded with phosphorus from farm fertilizers. Protecting water in agricultural watersheds will require knowledge of the local landscape along with strategies to address (1) drivers of climate chaos, (2) reduction in the highest river flows, and (3) ongoing inputs and legacy stores of phosphorus that are readily transported across land and water.

[Archived PDF of article]

Detecting the State of the Climate System via Artificial Intelligence to Improve Seasonal Forecasts and Inform Reservoir Operations

by Matteo Giuliani, Marta Zaniolo, Andrea Castelletti, Guido Davoli & Paul Block

Abstract: Increasingly variable hydrologic regimes combined with more frequent and intense extreme events are challenging water systems management worldwide. These trends emphasize the need of accurate medium- to long-term predictions to timely prompt anticipatory operations. Despite in some locations global climate oscillations and particularly the El Niño Southern Oscillation (ENSO) may contribute to extending forecast lead times, in other regions there is no consensus on how ENSO can be detected, and used as local conditions are also influenced by other concurrent climate signals. In this work, we introduce the Climate State Intelligence framework to capture the state of multiple global climate signals via artificial intelligence and improve seasonal forecasts. These forecasts are used as additional inputs for informing water system operations and their value is quantified as the corresponding gain in system performance. We apply the framework to the Lake Como basin, a regulated lake in northern Italy mainly operated for flood control and irrigation supply. Numerical results show the existence of notable teleconnection patterns dependent on both ENSO and the North Atlantic Oscillation over the Alpine region, which contribute in generating skillful seasonal precipitation and hydrologic forecasts. The use of this information for conditioning the lake operations produces an average 44% improvement in system performance with respect to a baseline solution not informed by any forecast, with this gain that further increases during extreme drought episodes. Our results also suggest that observed preseason sea surface temperature anomalies appear more valuable than hydrologic-based seasonal forecasts, producing an average 59% improvement in system performance.

[Archived PDF of article]

Landscape Water Storage and Subsurface Correlation from Satellite Surface Soil Moisture and Precipitation Observations

by Daniel J. Short Gianotti, Guido D. Salvucci, Ruzbeh Akbar, Kaighin A. McColl, Richard Cuenca & Dara Entekhabi

Abstract: Surface soil moisture measurements are typically correlated to some degree with changes in subsurface soil moisture. We calculate a hydrologic length scale, λ, which represents (1) the mean-state estimator of total column water changes from surface observations, (2) an e-folding length scale for subsurface soil moisture profile covariance fall-off, and (3) the best second-moment mass-conserving surface layer thickness for a simple bucket model, defined by the data streams of satellite soil moisture and precipitation retrievals. Calculations are simple, based on three variables: the autocorrelation and variance of surface soil moisture and the variance of the net flux into the column (precipitation minus estimated losses), which can be estimated directly from the soil moisture and precipitation time series. We develop a method to calculate the lag-one autocorrelation for irregularly observed time series and show global surface soil moisture autocorrelation. λ is driven in part by local hydroclimate conditions and is generally larger than the 50-mm nominal radiometric length scale for the soil moisture retrievals, suggesting broad subsurface correlation due to moisture drainage. In all but the most arid regions, radiometric soil moisture retrievals provide more information about ecosystem-relevant water fluxes than satellite radiometers can explicitly “see”; lower-frequency radiometers are expected to provide still more statistical information about subsurface water dynamics.

[Archived PDF of article]

Process-Guided Deep Learning Predictions of Lake Water Temperature

by Jordan S. Read, Xiaowei Jia, Jared Willard, Alison P. Appling, Jacob A. Zwart, Samantha K. Oliver, Anuj Karpatne, Gretchen J. A. Hansen, Paul C. Hanson, William Watkins, Michael Steinbach & Vipin Kumar

Abstract: The rapid growth of data in water resources has created new opportunities to accelerate knowledge discovery with the use of advanced deep learning tools. Hybrid models that integrate theory with state-of-the art empirical techniques have the potential to improve predictions while remaining true to physical laws. This paper evaluates the Process-Guided Deep Learning (PGDL) hybrid modeling framework with a use-case of predicting depth-specific lake water temperatures. The PGDL model has three primary components: a deep learning model with temporal awareness (long short-term memory recurrence), theory-based feedback (model penalties for violating conversation of energy), and model pre-training to initialize the network with synthetic data (water temperature predictions from a process-based model). In situ water temperatures were used to train the PGDL model, a deep learning (DL) model, and a process-based (PB) model. Model performance was evaluated in various conditions, including when training data were sparse and when predictions were made outside of the range in the training data set. The PGDL model performance (as measured by root-mean-square error (RMSE)) was superior to DL and PB for two detailed study lakes, but only when pretraining data included greater variability than the training period. The PGDL model also performed well when extended to 68 lakes, with a median RMSE of 1.65 °C during the test period (DL: 1.78 °C, PB: 2.03 °C; in a small number of lakes PB or DL models were more accurate). This case-study demonstrates that integrating scientific knowledge into deep learning tools shows promise for improving predictions of many important environmental variables.

[Archived PDF of article]

Adjustment of Radar-Gauge Rainfall Discrepancy Due to Raindrop Drift and Evaporation Using the Weather Research and Forecasting Model and Dual-Polarization Radar

by Qiang Dai, Qiqi Yang, Dawei Han, Miguel A. Rico-Ramirez & Shuliang Zhang

Abstract: Radar-gauge rainfall discrepancies are considered to originate from radar rainfall measurements while ignoring the fact that radar observes rain aloft while a rain gauge measures rainfall on the ground. Observations of raindrops observed aloft by weather radars consider that raindrops fall vertically to the ground without changing in size. This premise obviously does not stand because raindrop location changes due to wind drift and raindrop size changes due to evaporation. However, both effects are usually ignored. This study proposes a fully formulated scheme to numerically simulate both raindrop drift and evaporation in the air and reduces the uncertainties of radar rainfall estimation. The Weather Research and Forecasting model is used to simulate high-resolution three-dimensional atmospheric fields. A dual-polarization radar retrieves the raindrop size distribution for each radar pixel. Three schemes are designed and implemented using the Hameldon Hill radar in Lancashire, England. The first considers only raindrop drift, the second considers only evaporation, and the last considers both aspects. Results show that wind advection can cause a large drift for small raindrops. Considerable loss of rainfall is observed due to raindrop evaporation. Overall, the three schemes improve the radar-gauge correlation by 3.2%, 2.9%, and 3.8% and reduce their discrepancy by 17.9%, 8.6%, and 21.7%, respectively, over eight selected events. This study contributes to the improvement of quantitative precipitation estimation from radar polarimetry and allows a better understanding of precipitation processes.

[Archived PDF of article]

The Role of Collapsed Bank Soil on Tidal Channel Evolution: A Process-Based Model Involving Bank Collapse and Sediment Dynamics

by K. Zhao, Z. Gong, F. Xu, Z. Zhou, C. K. Zhang, G. M. E. Perillo & G. Coco

Abstract: We develop a process-based model to simulate the geomorphodynamic evolution of tidal channels, considering hydrodynamics, flow-induced bank erosion, gravity-induced bank collapse, and sediment dynamics. A stress-deformation analysis and the Mohr-Coulomb criterion, calibrated through previous laboratory experiments, are included in a model simulating bank collapse. Results show that collapsed bank soil plays a primary role in the dynamics of bank retreat. For bank collapse with small bank height, tensile failure in the middle of the bank (Stage I), tensile failure on the bank top (Stage II), and sectional cracking from bank top to the toe (Stage III) are present sequentially before bank collapse occurs. A significant linear relation is observed between bank height and the contribution of bank collapse to bank retreat. Contrary to flow-induced bank erosion, bank collapse prevents further widening since the collapsed bank soil protects the bank from direct bank erosion. The bank profile is linear or slightly convex, and the planimetric shape of tidal channels (gradually decreasing in width landward) is similar when approaching equilibrium, regardless of the consideration of bank erosion and collapse. Moreover, the simulated width-to-depth ratio in all runs is comparable with observations from the Venice Lagoon. This indicates that the equilibrium configuration of tidal channels depends on hydrodynamic conditions and sediment properties, while bank erosion and collapse greatly affect the transient behavior (before equilibrium) of the tidal channels. Overall, this contribution highlights the importance of collapsed bank soil in investigating tidal channel morphodynamics using a combined perspective of geotechnics and soil mechanics.

[Archived PDF of article]

A Physically Based Method for Soil Evaporation Estimation by Revisiting the Soil Drying Process

by Yunquan Wang, Oliver Merlin, Gaofeng Zhu & Kun Zhang

Abstract: While numerous models exist for soil evaporation estimation, they are more or less empirically based either in the model structure or in the determination of introduced parameters. The main difficulty lies in representing the water stress factor, which is usually thought to be limited by capillarity-supported water supply or by vapor diffusion flux. Recent progress in understanding soil hydraulic properties, however, have found that the film flow, which is often neglected, is the dominant process under low moisture conditions. By including the impact of film flow, a reexamination on the typical evaporation process found that this usually neglected film flow might be the dominant process for supporting the Stage II evaporation (i.e., the fast falling rate stage), besides the generally accepted capillary flow-supported Stage I evaporation and the vapor diffusion-controlled Stage III evaporation. A physically based model for estimating the evaporation rate was then developed by parameterizing the Buckingham-Darcy’s law. Interestingly, the empirical Bucket model was found to be a specific form of the proposed model. The proposed model requires the in-equilibrium relative humidity as the sole input for representing water stress and introduces no adjustable parameter in relation to soil texture. The impact of vapor diffusion was also discussed. Model testing with laboratory data yielded an excellent agreement with observations for both thin soil and thick soil column evaporation experiments. Model evaluation at 15 field sites generally showed a close agreement with observations, with a great improvement in the lower range of evaporation rates in comparison with the widely applied Priestley and Taylor Jet Propulsion Laboratory model.

[Archived PDF of article]

Floodplain Land Cover and Flow Hydrodynamic Control of Overbank Sedimentation in Compound Channel Flows

by Carmelo Juez, C. Schärer, H. Jenny, A. J. Schleiss & M. J. Franca

Abstract: Overbank sedimentation is predominantly due to fine sediments transported under suspension that become trapped and settle in floodplains when high-flow conditions occur in rivers. In a compound channel, the processes of exchanging water and fine sediments between the main channel and floodplains regulate the geomorphological evolution and are crucial for the maintenance of the ecosystem functions of the floodplains. These hydrodynamic and morphodynamic processes depend on variables such as the flow-depth ratio between the water depth in the main channel and the water depth in the floodplain, the width ratio between the width of the main channel and the width of the floodplain, and the floodplain land cover characterized by the type of roughness. This paper examines, by means of laboratory experiments, how these variables are interlinked and how the deposition of sediments in the compound channel is jointly determined by them. The combination of these compound channel characteristics modulates the production of vertically axised large turbulent vortical structures in the mixing interface. Such vortical structures determine the water mass exchange between the main channel and the floodplain, conditioning in turn the transport of sediment particles conveyed in the water, and, therefore, the resulting overbank sedimentation. The existence and pattern of sedimentation are conditioned by both the hydrodynamic variables (the flow-depth ratio and the width ratio) and the floodplain land cover simulated in terms of smooth walls, meadow-type roughness, sparse-wood-type roughness, and dense-wood-type roughness.

[Archived PDF of article]

Identifying Actionable Compromises: Navigating Multi-city Robustness Conflicts to Discover Cooperative Safe Operating Spaces for Regional Water Supply Portfolios

by D. F. Gold, P. M. Reed, B. C. Trindade & G. W. Characklis

Summary: Cooperation among neighboring urban water utilities can help water managers face challenges stemming from climate change and population growth. Water utilities can cooperate by coordinating water transfers and water restrictions in times of water scarcity (drought) so that water is provided to areas that need it most. In order to successfully implement these policies, however, cooperative partners must find a compromise that is acceptable to all regional actors, a task complicated by asymmetries in resources and risks often present in regional systems. The possibility of deviations from agreed upon actions is another complicating factor that has not been addressed in water resources literature. Our study focuses on four urban water utilities in the Research Triangle region of North Carolina who are investigating cooperative drought mitigation strategies. We contribute a framework that includes the use of simulation models, optimization algorithms, and statistical tools to aid cooperating partners in finding acceptable compromises that are tolerant modest deviations in planned actions. Our results can be used by regional utilities to avoid or alleviate potential planning conflicts and are broadly applicable to urban regional water supply planning across the globe.

[Archived PDF of article]

Detecting Changes in River Flow Caused by Wildfires, Storms, Urbanization, Regulation, and Climate across Sweden

by Berit Arheimer & Göran Lindström

Abstract: Changes in river flow may appear from shifts in land cover, constructions in the river channel, and climatic change, but currently there is a lack of understanding of the relative importance of these drivers. Therefore, we collected gauged river flow time series from 1961 to 2018 from across Sweden for 34 disturbed catchments to quantify how the various types of disturbances have affected river flow. We used trend analysis and the differences in observations versus hydrological modeling to explore the effects on river flow from (1) land cover changes from wildfires, storms, and urbanization; (2) dam constructions with regulations for hydropower production; and (3) climate-change impact in otherwise undisturbed catchments. A mini model ensemble, consisting of three versions of the S-HYPE model, was used, and the three models gave similar results. We searched for changes in annual and daily stream flow, seasonal flow regime, and flow duration curves. The results show that regulation of river flow has the largest impact, reducing spring floods with up to 100% and increasing winter flow by several orders of magnitude, with substantial effects transmitted far downstream. Climate changed the total river flow up to 20%. Tree removal by wildfires and storms has minor impacts at medium and large scales. Urbanization, on the contrary, showed a 20% increase in high flows also at medium scales. This study emphasizes the benefits of combining observed time series with numerical modeling to exclude the effect of varying weather conditions, when quantifying the effects of various drivers on long-term streamflow shifts.

[Archived PDF of article]

Assessing the Feasibility of Satellite-Based Thresholds for Hydrologically Driven Landsliding

by Matthew A. Thomas, Brian D. Collins & Benjamin B. Mirus

Summary: Soil wetness and rainfall contribute to landslides across the world. Using soil moisture sensors and rain gauges, these environmental conditions have been monitored at numerous points across the Earth’s surface to define threshold conditions, above which landsliding should be expected for a localized area. Satellite-based technologies also deliver estimates of soil wetness and rainfall, potentially offering an approach to develop thresholds as part of landslide warning systems over larger spatial scales. To evaluate the potential for using satellite-based measurements for landslide warning, we compare the accuracy of landslide thresholds defined with ground- versus satellite-based soil wetness and rainfall information. We find that the satellite-based data over-predict soil wetness during the time of year when landslides are most likely to occur, resulting in thresholds that also over-predict the potential for landslides relative to thresholds informed by direct measurements on the ground. Our results encourage the installation of more ground-based monitoring stations in landslide-prone settings and the cautious use of satellite-based data when more direct measurements are not available.

[Archived PDF of article]

Modeling the Translocation and Transformation of Chemicals in the Soil-Plant Continuum: A Dynamic Plant Uptake Module for the HYDRUS Model

by Giuseppe Brunetti, Radka Kodešová & Jiří Šimůnek

Abstract: Food contamination is responsible for thousands of deaths worldwide every year. Plants represent the most common pathway for chemicals into the human and animal food chain. Although existing dynamic plant uptake models for chemicals are crucial for the development of reliable mitigation strategies for food pollution, they nevertheless simplify the description of physicochemical processes in soil and plants, mass transfer processes between soil and plants and in plants, and transformation in plants. To fill this scientific gap, we couple a widely used hydrological model (HYDRUS) with a multi-compartment dynamic plant uptake model, which accounts for differentiated multiple metabolization pathways in plant’s tissues. The developed model is validated first theoretically and then experimentally against measured data from an experiment on the translocation and transformation of carbamazepine in three vegetables. The analysis is further enriched by performing a global sensitivity analysis on the soilplant model to identify factors driving the compound’s accumulation in plants’ shoots, as well as to elucidate the role and the importance of soil hydraulic properties on the plant uptake process. Results of the multilevel numerical analysis emphasize the model’s flexibility and demonstrate its ability to accurately reproduce physicochemical processes involved in the dynamic plant uptake of chemicals from contaminated soils.

[Archived PDF of article]

Physical Controls on Salmon Redd Site Selection in Restored Reaches of a Regulated, Gravel-Bed River

by Lee R. Harrison, Erin Bray, Brandon Overstreet, Carl J. Legleiter, Rocko A. Brown, Joseph E. Merz, Rosealea M. Bond, Colin L. Nicol & Thomas Dunne

Abstract: Large-scale river restoration programs have emerged recently as a tool for improving spawning habitat for native salmonids in highly altered river ecosystems. Few studies have quantified the extent to which restored habitat is utilized by salmonids, which habitat features influence redd site selection, or the persistence of restored habitat over time. We investigated fall-run Chinook salmon spawning site utilization and measured and modeled corresponding habitat characteristics in two restored reaches: a reach of channel and floodplain enhancement completed in 2013 and a reconfigured channel and floodplain constructed in 2002. Redd surveys demonstrated that both restoration projects supported a high density of salmon redds, 3 and 14 years following restoration. Salmon redds were constructed in coarse gravel substrates located in areas of high sediment mobility, as determined by measurements of gravel friction angles and a grain entrainment model. Salmon redds were located near transitions between pool-riffle bedforms in regions of high predicted hyporheic flows. Habitat quality (quantified as a function of stream hydraulics) and hyporheic flow were both strong predictors of redd occurrence, though the relative roles of these variables differed between sites. Our findings indicate that physical controls on redd site selection in restored channels were similar to those reported for natural channels elsewhere. Our results further highlight that in addition to traditional habitat criteria (e.g., water depth, velocity, and substrate size), quantifying sediment texture and mobility, as well as intragravel flow, provides a more complete understanding of the ecological benefits provided by river restoration projects.

[Archived PDF of article]

Mountain-Block Recharge: A Review of Current Understanding

by Katherine H. Markovich, Andrew H. Manning, Laura E. Condon & Jennifer C. McIntosh

Abstract: Mountain-block recharge (MBR) is the subsurface inflow of groundwater to lowland aquifers from adjacent mountains. MBR can be a major component of recharge but remains difficult to characterize and quantify due to limited hydrogeologic, climatic, and other data in the mountain block and at the mountain front. The number of MBR-related studies has increased dramatically in the 15 years since the last review of the topic was conducted by Wilson and Guan (2004), generating important advancements. We review this recent body of literature, summarize current understanding of factors controlling MBR, and provide recommendations for future research priorities. Prior to 2004, most MBR studies were performed in the southwestern United States. Since then, numerous studies have detected and quantified MBR in basins around the world, typically estimating MBR to be 5–50% of basin-fill aquifer recharge. Theoretical studies using generic numerical modeling domains have revealed fundamental hydrogeologic and topographic controls on the amount of MBR and where it originates within the mountain block. Several mountain-focused hydrogeologic studies have confirmed the widespread existence of mountain bedrock aquifers hosting considerable groundwater flow and, in some cases, identified the occurrence of interbasin flow leaving headwater catchments in the subsurface—both of which are required for MBR to occur. Future MBR research should focus on the collection of high-priority data (e.g., subsurface data near the mountain front and within the mountain block) and the development of sophisticated coupled models calibrated to multiple data types to best constrain MBR and predict how it may change in response to climate warming.

[Archived PDF of article]

An Adjoint Sensitivity Model for Steady-State Sequentially Coupled Radionuclide Transport in Porous Media

by Mohamed Hayek, Banda S. RamaRao & Marsh Lavenue

Abstract: This work presents an efficient mathematical/numerical model to compute the sensitivity coefficients of a predefined performance measure to model parameters for one-dimensional steady-state sequentially coupled radionuclide transport in a finite heterogeneous porous medium. The model is based on the adjoint sensitivity approach that offers an elegant and computationally efficient alternative way to compute the sensitivity coefficients. The transport parameters include the radionuclide retardation factors due to sorption, the Darcy velocity, and the effective diffusion/dispersion coefficients. Both continuous and discrete adjoint approaches are considered. The partial differential equations associated with the adjoint system are derived based on the adjoint state theory for coupled problems. Physical interpretations of the adjoint states are given in analogy to results obtained in the theory of groundwater flow. For the homogeneous case, analytical solutions for primary and adjoint systems are derived and presented in closed forms. Numerically calculated solutions are compared to the analytical results and show excellent agreements. Insights from sensitivity analysis are discussed to get a better understanding of the values of sensitivity coefficients. The sensitivity coefficients are also computed numerically by finite differences. The numerical sensitivity coefficients successfully reproduce the analytically derived sensitivities based on adjoint states. A derivative-based global sensitivity method coupled with the adjoint state method is presented and applied to a real field case represented by a site currently being considered for underground nuclear storage in Northern Switzerland, “Zürich Nordost,” to demonstrate the proposed method. The results show the advantage of the adjoint state method compared to other methods in term of computational effort.

[Archived PDF of article]

Hydraulic Reconstruction of the 1818 Giétro Glacial Lake Outburst Flood

by C. Ancey, E. Bardou, M. Funk, M. Huss, M. A. Werder & T. Trewhela

Summary: Every year, natural and man-made dams fail and cause flooding. For public authorities, estimating the risk posed by dams is essential to good risk management. Efficient computational tools are required for analyzing flood risk. Testing these tools is an important step toward ensuring their reliability and performance. Knowledge of major historical floods makes it possible, in principle, to benchmark models, but because historical data are often incomplete and fraught with potential inaccuracies, validation is seldom satisfactory. Here we present one of the few major historical floods for which information on flood initiation and propagation is available and detailed: the Giétro flood. This flood occurred in June 1818 and devastated the Drance Valley in Switzerland. In the spring of that year, ice avalanches blocked the valley floor and formed a glacial lake, whose volume is today estimated at 25×106 m3. The local authorities initiated protection works: A tunnel was drilled through the ice dam, and about half of the stored water volume was drained in 2.5 days. On 16 June 1818, the dam failed suddenly because of significant erosion at its base; this caused a major flood. This paper presents a numerical model for estimating flow rates, velocities, and depths during the dam drainage and flood flow phases. The numerical results agree well with historical data. The flood reconstruction shows that relatively simple models can be used to estimate the effects of a major flood with good accuracy.

[Archived PDF of article]

The Representation of Hydrological Dynamical Systems Using Extended Petri Nets (EPN)

by Marialaura Bancheri, Francesco Serafin & Riccardo Rigon

Abstract: This work presents a new graphical system to represent hydrological dynamical models and their interactions. We propose an extended version of the Petri Nets mathematical modeling language, the Extended Petri Nets (EPN), which allows for an immediate translation from the graphics of the model to its mathematical representation in a clear way. We introduce the principal objects of the EPN representation (i.e., places, transitions, arcs, controllers, and splitters) and their use in hydrological systems. We show how to cast hydrological models in EPN and how to complete their mathematical description using a dictionary for the symbols and an expression table for the flux equations. Thanks to the compositional property of EPN, we show how it is possible to represent either a single hydrological response unit or a complex catchment where multiple systems of equations are solved simultaneously. Finally, EPN can be used to describe complex Earth system models that include feedback between the water, energy, and carbon budgets. The representation of hydrological dynamical systems with EPN provides a clear visualization of the relations and feedback between subsystems, which can be studied with techniques introduced in nonlinear systems theory and control theory.

[Archived PDF of article]

A Regularization Approach to Improve the Sequential Calibration of a Semidistributed Hydrological Model

by A. de Lavenne, V. Andréassian, G. Thirel, M.-H. Ramos & C. Perrin

Abstract: In semidistributed hydrological modeling, sequential calibration usually refers to the calibration of a model by considering not only the flows observed at the outlet of a catchment but also the different gauging points inside the catchment from upstream to downstream. While sequential calibration aims to optimize the performance at these interior gauged points, we show that it generally fails to improve performance at ungauged points. In this paper, we propose a regularization approach for the sequential calibration of semidistributed hydrological models. It consists in adding a priori information on optimal parameter sets for each modeling unit of the semi-distributed model. Calibration iterations are then performed by jointly maximizing simulation performance and minimizing drifts from the a priori parameter sets. The combination of these two sources of information is handled by a parameter k to which the method is quite sensitive. The method is applied to 1,305 catchments in France over 30 years. The leave-one-out validation shows that, at locations considered as ungauged, model simulations are significantly improved (over all the catchments, the median KGE criterion is increased from 0.75 to 0.83 and the first quartile from 0.35 to 0.66), while model performance at gauged points is not significantly impacted by the use of the regularization approach. Small catchments benefit most from this calibration strategy. These performances are, however, very similar to the performances obtained with a lumped model based on similar conceptualization.

[Archived PDF of article]

Proneness of European Catchments to Multiyear Streamflow Droughts

by Manuela I. Brunner & Lena M. Tallaksen

Summary: Droughts lasting longer than 1 year can have severe ecological, social, and economic impacts. They are characterized by below-average flows, not only during the low-flow period but also in the high-flow period when water stores such as groundwater or artificial reservoirs are usually replenished. Limited catchment storage might worsen the impacts of droughts and make water management more challenging. Knowledge on the occurrence of multiyear drought events enables better adaptation and increases preparedness. In this study, we assess the proneness of European catchments to multiyear droughts by simulating long discharge records. Our findings show that multiyear drought events mainly occur in regions where the discharge seasonality is mostly influenced by rainfall, whereas catchments whose seasonality is dominated by melt processes are less affected. The strong link between the proneness of a catchment to multiyear events and its discharge seasonality leads to the conclusion that future changes toward less snow storage and thus less snow melt will increase the probability of multiyear drought occurrence.

[Archived PDF of article]

Equifinality and Flux Mapping: A New Approach to Model Evaluation and Process Representation under Uncertainty

by Sina Khatami, Murray C. Peel, Tim J. Peterson & Andrew W. Western

Abstract: Uncertainty analysis is an integral part of any scientific modeling, particularly within the domain of hydrological sciences given the various types and sources of uncertainty. At the center of uncertainty rests the concept of equifinality, that is, reaching a given endpoint (finality) through different pathways. The operational definition of equifinality in hydrological modeling is that various model structures and/or parameter sets (i.e., equal pathways) are equally capable of reproducing a similar (not necessarily identical) hydrological outcome (i.e., finality). Here we argue that there is more to model equifinality than model structures/parameters, that is, other model components can give rise to model equifinality and/or could be used to explore equifinality within model space. We identified six facets of model equifinality, namely, model structure, parameters, performance metrics, initial and boundary conditions, inputs, and internal fluxes. Focusing on model internal fluxes, we developed a methodology called flux mapping that has fundamental implications in understanding and evaluating model process representation within the paradigm of multiple working hypotheses. To illustrate this, we examine the equifinality of runoff fluxes of a conceptual rainfall-runoff model for a number of different Australian catchments. We demonstrate how flux maps can give new insights into the model behavior that cannot be captured by conventional model evaluation methods. We discuss the advantages of flux space, as a subspace of the model space not usually examined, over parameter space. We further discuss the utility of flux mapping in hypothesis generation and testing, extendable to any field of scientific modeling of open complex systems under uncertainty.

[Archived PDF of article]

Role of Extreme Precipitation and Initial Hydrologic Conditions on Floods in Godavari River Basin, India

by Shailesh Garg & Vimal Mishra

Abstract: Floods are the most frequent natural calamity in India. The Godavari river basin (GRB) witnessed several floods in the past 50 years. Notwithstanding the large damage and economic loss, the role of extreme precipitation and antecedent moisture conditions on floods in the GRB remains unexplored. Using the observations and the well-calibrated Variable Infiltration Capacity model, we estimate the changes in the extreme precipitation and floods in the observed (1955–2016) and projected future (2071–2100) climate in the GRB. We evaluate the role of initial hydrologic conditions and extreme precipitation on floods in both observed and projected future climate. We find a statistically significant increase in annual maximum precipitation for the catchments upstream of four gage stations during the 1955–2016 period. However, the rise in annual maximum streamflow at all the four gage stations in GRB was not statistically significant. The probability of floods driven by extreme precipitation (PFEP) varies between 0.55 and 0.7 at the four gage stations of the GRB, which declines with the size of the basins. More than 80% of extreme precipitation events that cause floods occur on wet antecedent moisture conditions at all the four locations in the GRB. The frequency of extreme precipitation events is projected to rise by two folds or more (under RCP 8.5) in the future (2071–2100) at all four locations. However, the increased frequency of floods under the future climate will largely be driven by the substantial rise in the extreme precipitation events rather than wet antecedent moisture conditions.

[Archived PDF of article]

Research Letters

Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers

by Woei Keong Kuan, Pei Xin, Guangqiu Jin, Clare E. Robinson, Badin Gibbes & Ling Li

Abstract: Tides and seasonally varying inland freshwater input, with different fluctuation periods, are important factors affecting flow and salt transport in coastal unconfined aquifers. These processes affect submarine groundwater discharge (SGD) and associated chemical transport to the sea. While the individual effects of these forcings have previously been studied, here we conducted physical experiments and numerical simulations to evaluate the interactions between varying inland freshwater input and tidal oscillations. Varying inland freshwater input was shown to induce significant water exchange across the aquifer-sea interface as the saltwater wedge shifted landward and seaward over the fluctuation cycle. Tidal oscillations led to seawater circulations through the intertidal zone that also enhanced the density-driven circulation, resulting in a significant increase in the total SGD. The combination of the tide and varying inland freshwater input, however, decreased the SGD components driven by the separate forcings (e.g., tides and density). Tides restricted the landward and seaward movement of the saltwater wedge in response to the varying inland freshwater input in addition to reducing the time delay between the varying freshwater input signal and landward-seaward movement in the saltwater wedge interface. This study revealed the nonlinear interaction between tidal fluctuations and varying inland freshwater input will help to improve our understanding of SGD, seawater intrusion, and chemical transport in coastal unconfined aquifers.

[Archived PDF of article]

Essay 96: Education and London’s Centrality in Global Finance: Then and Now

To understand our world, we have to go back to classics of understanding such as Lombard Street [Project Gutenberg ebook] which gives one a vivid sense of London’s rise as world’s banker, already in 1873. 

Our current world was certainly shaped by these long-term historical trends.

…But very few persons are aware how much greater the ready balance—the floating loan-fund which can be lent to any one or for any purpose—is in England than it is anywhere else in the world. A very few figures will show how large the London loan-fund is, and how much greater it is than any other. The known deposits—the deposits of banks which publish their accounts—are, in

London (31st December, 1872). . . . . . . .£120,000,000
Paris (27th February, 1873) . . . . . . . . . .13,000,000
New York (February, 1873) . . . . . . . . . .40,000,000
German Empire (31st January, 1873) . . .8,000,000

And the unknown deposits—the deposits in banks which do not publish their accounts—are in London much greater than those in any other of these cities. The bankers’ deposits of London are many times greater than those of any other city—those of Great Britain many times greater than those of any other country.

Of course the deposits of bankers are not a strictly accurate measure of the resources of a Money Market. On the contrary, much more cash exists out of banks in France and Germany, and in all non-banking countries, than could be found in England or Scotland, where banking is developed. But that cash is not, so to speak, “Money-Market money”: it is not attainable. Nothing but their immense misfortunes, nothing but a vast loan in their own securities, could have extracted the hoards of France from the custody of the French people. The offer of no other securities would have tempted them, for they had confidence in no other securities. For all other purposes the money hoarded was useless and might as well not have been hoarded. But the English money is “borrowable” money. Our people are bolder in dealing with their money than any continental nation, and even if they were not bolder, the mere fact that their money is deposited in a bank makes it far more obtainable. A million in the hands of a single banker is a great power; he can at once lend it where he will, and borrowers can come to him, because they know or believe that he has it. But the same sum scattered in tens and fifties through a whole nation is no power at all: no one knows where to find it or whom to ask for it. Concentration of money in banks, though not the sole cause, is the principal cause which has made the Money Market of England so exceedingly rich, so much beyond that of other countries.

…I believe that our system, though curious and peculiar, may be worked safely; but if we wish so to work it, we must study it. We must not think we have an easy task when we have a difficult task, or that we are living in a natural state when we are really living in an artificial one. Money will not manage itself, and Lombard Street has a great deal of money to manage.

Essay 34: Arguments Without End: Are They Good or Bad?

The Dutch historian Pieter Geyl (died in 1966) coined the phrase “argument without end” to get at the constant reappearance of old arguments or viewpoints. One gets the impression that arguments are either persistent or perhaps permanent. One simplistic example could be argument about socialism: Sweden is “good,” but Venezuela (or Cuba) is bad. This book takes the view that “arguments without end” are not the end of knowledge but rather a potential beginning: it could be that some issues cannot be captured by one school of thought: the awarding of the 1974 Nobel Prize to both Hayek (“the right”) and Myrdal (“the left”) is an example of this need for hybridity. Both Hayek and Myrdal are each seeing something valid and it’s a “fool’s errand” to decide who is “eternally” correct.

Let’s apply this thinking to a deep “argument without end” within and about history.

Michel Foucault (died in 1984) following Nietzsche, argues that history seems “linear” but is more random and non-linear than the “linear” historians see or admit.

There’s an aphorism in Nietzsche, (from his The Dawn) which Foucault uses…history is made by the “iron-hand of necessity shaking the dice-box of chance.”

In other words the world we know, traveling somehow from the assassination of Kennedy (November 2, 1963) to the impeachment hearings of Trump in October 2019, must be thought of as a kind of “random walk” behind which are trends, cycles, so that one gets a fusion of structure and surprise. If you emphasize surprise you’re closer to Foucault than to those narrative historians who think they can show you the exact threads which connect “then and now.”

Here’s an example of such a historian, the celebrated G.R. Elton of England, whose classic The Tudor Revolution in Government is a masterpiece of orthodox analysis. The book centers on the administrative revolution in the 1530s in England which implied, says Elton, “As regards political and social structure, the sixteenth century produced something quite new in England—the self-contained sovereign state in which no power on earth could challenge the supremacy of statute made by the crown in parliament.”

“In this revolution, in this making of a new kind of state productive of a new kind of society, administrative reforms played their part. It is against this background of controlled upheaval that they must be seen and understood.”

(Elton, The Tudor Revolution in Government, Cambridge University press, 1966, page 426/427)

Orthodox historians see history as a “nail-down-able” system of storylines and the controlled upheavals have a direction (teleology) which allows you to use—in this case the 1530s in England—as a beginning, an origin, a “datum line,” and once you have this clear starting point you can follow the story to now and include comparative developments in France or Germany or China.

The orthodox “explain strategy” starts with an origin, a “starting gate” like a horse-race.

The FoucaultNietzsche view is that these starting points are not entirely useless but in the end don’t help you because history is in the end governed by “the dice-box of chance” even if it is held by “the iron-hand of necessity.” History is more “upheaval” than “control” more surprise than structure. “Determinism” such as perhaps based by pinning down a starting point from which one can “build out,” is a wish-dream since history is nonlinear and nondeterministic. Even Elton’s phrase “controlled upheaval” is full of questions and problems.

Modern “complexity theory” in mathematics tries to get at these differences analytically. A “meta-intelligent” student would go from this historians’ “argument without end” to the analysis of complexity in math as a way of rounding out the exploration.

An “argument without end” can thus be useful if the student does not insist on some final “apodictic” or certain-forever answer.

Essay 30: Magic or Sacred Geography as a Kind of Silent Education

Magic and its clone, sacred geography, are all around us and are crucial organizing principles for the way people think. Such emotions are an overlay over all formal education.

For Communists, the grave of Marx in Highgate Cemetery in England is sacred ground.  For some German soldiers after WWII who committed suicide on the steps in Feldherrnhalle (“Field Marshall’s Hall”—a display in Munich in Odeonsplatz of large statues of famous military leaders in German history), these statues and their place in Munich “means” something magical or sacred to them. North Koreans have Paektu Mountain which Kim recently ascended in a ritual addressed to the North Koreans. Think of Camelot or Lourdes.  Think of sites such as the Lincoln Memorial or Notre-Dame Cathedral in Paris or “holy sites” in Jerusalem or Mecca.

Think of magical and sacred things like the three imperial regalia in Japan which Emperor Hirohito fixated on at the end of WWII.

How does this kind of thinking permeate our lives in a way that nobody quite sees clearly:

The left in American politics (Bernie Sanders, Jeffrey Sachs, et al) explicitly or implicitly, think of Scandinavian social and economic systems as a kind of “magic geography” (i.e., defects and problems are not “welcomed” in their idealized visions). On the right, there’s a Singapore paradise of the imagination (what magic geography is) whereas Boris Johnson of England sees a “high wage, low tax” investment utopia which serve as a marvelous locale for the founding of both new businesses and new families. In this vision, men found businesses and women found or establish families, so everybody’s happy.

These competing visions can be traced back as far as you like, but we point to 1974 when Hayek (“the right”) and Myrdal (“the left”) shared the Nobel Prize for Economics.

Professor Niall Ferguson, the conservative Harvard (now Stanford) financial historian (you may have seen his The Ascent of Money PBS mini-series), had a program years ago on educational TV where he walked around places in Chile that he presented as a pension “heaven.” Chile is now kind of falling apart with street riots convulsing Santiago. (Ferguson’s ideal Milton Friedman of Chicago was the main advisor of General Pinochet after the 1973 Chilean coup.

What none of these people see is that social reality is complex and highly changeable and that “magicalizing” one place or system (Sweden, Hong Kong, Singapore, Chile) won’t work because successes that look solid or eternal are often caused by all kinds of “conjunctural” (i.e., of the moment) factors which don’t last “forever.”

Thus, much less “dogmatism” is called for so that one is not “swept along” by “ideological foolishness.” embedded in “magical geography” or its clone “sacred geography.”