Macropores and water flow in soils revisited
Summary (2 min read)
Introduction
- In today’s political and religious spheres that certain emerging institutions have, namely the institutions now called ‘Ecumenical Platforms’.
- This article is an analysis of the conditions under which such rejection becomes possible.
The Problem of Belonging and the Role of Christian Religion
- Belonging is now very problematic in postcolonial and postwar Angola.
- In order to understand their sense of exclusion, the authors need to reassess the entanglement of history and religion and the part Bakongo played in the making of the nation.
- The three movements - the UPNA, later called UPA (União dos Povos de Angola) and finally FNLA, UNITA, and the MPLA- that started the anti-colonial war in the early 1960s had Protestant roots.
- The anti-colonial war has sometimes somewhat problematically been called a ‘Protestant vs Catholic’ conflict, because the Portuguese colonialists were largely Catholic, and openly anti-Protestant.
- See also the earlier study by M. Gonçalves, Angola: reconciliação e paz em perspectiva cristã (Luanda, CEAST, 1995), Angola: justiça e paz nas intervenções da Igreja Católica 1989-2002 (Luanda, Texto Editores, 2013).
From Polarized Christianity to Proliferating Churches
- The entanglements of churches, the Marxist Leninist ideology of the MPLA and the civil war have been the focus of several studies.
- There is solid research on ecumenical initiatives and their role in creating peace and conflict resolution, in particular in the 1990s and in the early 2000s, when the war was definitely over.
- The ruling party, in collaboration with INAR and the Ministry of Justice, seeks to force illegal churches to create certain Ecumenical Platforms.
- Each such Platform groups churches with similar doctrines, thus making it possible to reach the 100,000 threshold of legalization.
New Non-Christian and Anti-Christian Churches
- A significant stumbling block comes from the fact that some religious institutions which are churches are distinctively and professedly not Christian.
- In the early post-council days, however, Angolan (i.e. Portuguese) Catholics and Protestants were fighting against each other, and even the World Council of Churches was perceived as suspect by the Portuguese colonizers.
- The Religious Landscape of Mbanza Kongo Although exiled people returned in 1975, the immediate civil war again provoked a massive flight to the Democratic Republic of the Congo (DRC), and the northern provinces were again largely, though not entirely, depopulated between 1975 and 1993, also known as Priests and Bangunza.
- Moments of negotiation do occur, but so too is fierce opposition sustained.
Theology and the Anti-ecumenical Persecution of Prophets
- In my opinion, it was mostly for a political reason that these prophets were so fiercely prosecuted.
- Serving the God of the Africans, and thus having a theological motive which they knew the colonizers hated, they engaged in revitalization.
- There is a perceived crisis of memory, and it has a deep theological significance for Bakongo.
- Members of churches based on the learning of the bangunza very often blame Christian churches, including that of Kimbangu, for having destroyed Kongo culture and perverted Kongo cultural inheritance.
- ‘Christianity is their enemy’, I was told by another BDK interviewee, and similar phrases were obtained in many of my interviews and conversations with religious leaders of local churches.
A Wide Spectrum of Churches
- At the one extreme, the authors find churches like the Catholic and the mainstream Protestant churches, and at the other extreme, movements that explicitly reject Christianity and are led by bangunza, such as the BDK and many others.
- For the biography of Simão Toko and its contested interpretations, see the study of R. Blanes, A Prophetic Trajectory: Ideologies of Place, Time and Belonging in an Angolan Religious Movement ,(Oxford and New York, Berghahn, 2013).
- In good measure, it is difficult for the observer to distinguish the differences among them.
- Some of these mpeve anlongo churches may have been making such claims for a long time, but there is room to suspect that some others may be modifying their theology so as eventually to be able to jump onto one ‘Ecumenical Platform’ or other and gain legality and legitimacy.
- For this reason, it could perhaps have become a locus of encounter between, on the one hand, the nativistic approaches of the bangunza-based religions and, on the other, the Christian element of the churches and the governmental forces fighting for ecumenism.
Conclusion
- Mbanza Kongo is a place of effervescent exchange and cultural dynamism and creativity, and in that respect a perfect laboratory to study the cultural logics underneath religious pluralism and the possibility of grassroots ecumenism.
- The difficulty is that, in the conditions of post-war religious pluralism, living together implies sharing contested views of the past and notions of divinity..
- One of the things I came to realize in my fieldwork in Mbanza Kongo is that people are concerned about many things, and that religion is merely one of them.
- In their last visit to a farm, the authors found ourselves talking to a group of people who were farming together, sharing a shelter and eating together during the days they spent in the farm every week.
- I conducted nine months of fieldwork in Mbanza Kongo in between 2014 and 2016, building upon earlier fieldwork in the DRC and among Kimbanguist diasporas in Europe.
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Citations
542 citations
Cites background from "Macropores and water flow in soils ..."
...Despite being in use for more than a century, Richards equation–based models are still not suitable for all soil types (particularly soils with high clay or organic matter contents), and there is still not an adequate physical theory linking all types of flow (Beven and Germann, 2013)....
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424 citations
Cites background from "Macropores and water flow in soils ..."
...Yet we can still learn much about the variability and scaling of meteorological and hydrological factors and processes controlling slope failure (Almeida et al., 2017; Beven & Germann, 2013; Corominas et al., 2013; Crosta & Frattini, 2001; von Ruette et al., 2014)....
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374 citations
Cites background from "Macropores and water flow in soils ..."
...…flow dynamics in process-based models has been criticized for over-emphasizing capillarity and neglecting the role of preferential flow (Nimmo, 2012; Beven and Germann, 2013), for being in some ways ‘overly simplistic’ (Gray and Hassanizadeh, 1991; Niessner and Hassanizadeh, 2008), and for being…...
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347 citations
Cites background from "Macropores and water flow in soils ..."
...Similar relationships can be developed for other profiles of hydraulic conductivity [e.g., Beven, 1981]; for specific soil moisture characteristic curves [e.g., Rasmussen et al., 2000]; and for preferential flows based on Stokes law [Beven and Germann, 2013] (see Table 1)....
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...…Relationships for Velocities and Celerities for Different Types of Flow [After Beven, 1989, 2012a; Rasmussen et al., 2000; Torres et al., 1998; Beven and Germann, 2013; Gonwa and Kavvas, 1986]a Type of Flow Mean Velocity (LT21) Celerity (LT21) c/v Free surface flow: St. Venant equation v c 5…...
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262 citations
Cites background from "Macropores and water flow in soils ..."
...In the case of the prediction of aquifer recharge, uncertainty could result from inadequate handling of some key processes, like preferential transport, whose monitoring and modeling remain very challenging at this stage Beven and Germann (2013)....
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References
5,340 citations
4,855 citations
"Macropores and water flow in soils ..." refers methods in this paper
...Tensiometers and time domain reflectrometry (TDR) [see, for instance, Topp et al., 1980] were used to record capillary potentials and volumetric water contents at nine depths....
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2,532 citations
2,222 citations
"Macropores and water flow in soils ..." refers background in this paper
...…on small soil samples) presumes that the Darcy-Richards equation holds at larger scales of application, and that the parameter values are constant in time and space for a given soil horizon [see, for example, Wösten, 1999; Acutis and Donatelli, 2003; Schaap et al. 2001; McBratney et al., 2002]....
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...The widespread use of pedotransfer functions (mostly derived from experiments on small soil samples) presumes that the Darcy-Richards equation holds at larger scales of application, and that the parameter values are constant in time and space for a given soil horizon [see, for example, Wösten, 1999; Acutis and Donatelli, 2003; Schaap et al. 2001; McBratney et al., 2002]....
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1,985 citations
"Macropores and water flow in soils ..." refers background in this paper
...At the hillslope scale, in the simplest kinematic wave analogy, this can be expressed as the difference between the wave celerity that depends on storage deficits and the pore water velocities that will depend on storage [see Beven, 2012, p.145]....
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...…of perceptual models of the role of macropores and preferential flows in profile, hillslope and catchment responses have been presented [e.g., Beven, 2004a, 2012, chap.1; McDonnell, 1990; Brammer and McDonnell, 1996; Noguchi et al., 1999; Buttle and MacDonald, 2002; McGlynn et al., 2002;…...
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...This is not a new insight, it has been known for decades [e.g., Dagan and Bresler, 1983], but with very little effect on modeling practice [see discussion in Beven, 1989, 2001, 2006, 2012]....
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...It is important to differentiate between pore water velocities that control transport processes, and celerities that control the propagation of perturbations through the system and therefore control hydrograph responses [e.g., Beven, 2012, chap....
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...In fact, although hillslope kinematic wave models [e.g., Beven, 1981b, 1982a, 1982b; Davies and Beven, 2012] are often represented as if they involve saturation from the base of the profile, such an assumption is not necessary....
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Related Papers (5)
Frequently Asked Questions (13)
Q2. Why is the flow-restraining force assumed according to the material-specific retention curve?
Because neither velocity nor acceleration occurs, hydrostatic conditions are assumed according to the material-specific retention curve.
Q3. How many depths were used to record water contents?
Tensiometers and time domain reflectrometry (TDR) [see, for instance, Topp et al., 1980] were used to record capillary potentials and volumetric water contents at nine depths.
Q4. What is the main reason why the inverse methods are so sensitive to noise?
Since the inverse methods applied can be highly susceptible to overfitting without adequate noise assessment then one can risk misinterpretation of preferential flow when the true cause is inappropriate assessment of signal to noise.
Q5. What techniques have been applied to the study of preferential flow in soil?
Various techniques of tomographic imaging have been applied to the study of preferential flow in soil including X-ray (CT), electrical resistance (ERT), radar and ultrasound.
Q6. What was the main reason for the infiltration into reconstructed soils?
Infiltration into reconstructed soils was mainly through the soil matrix because no macropores had formed since reconstruction.[24]
Q7. What is the range of effects of capillary gradients in the pores?
In smaller pores, capillarity and capillary gradients can play a role in controlling water movement, but the authors expect the range of such effects to be small scale and local.
Q8. What is the need to combine flow measurements with tracer experiments?
At both profile and hillslope scales, there is also a need to combine flow measurements with tracer experiments to test whether assumptions about flow velocities can equally reproduce the celerities controlling the hydrograph.
Q9. Why is it important to use both data types to characterize the response of a plot,?
This is because in order to fully characterize the response of a plot, a field, a hillslope or a catchment, both data types, hydrograph and tracer concentrations are required to allow the differentiation of celerity effects that control the hydrograph response and the distributions of pore water velocities that control the tracer response.
Q10. How can a system of lateral flow be able to cause the displacement of stored water?
Where the soil is saturated, this can be achieved by the propagation of pressure waves through the system, such that the build up of pressure in an upslope macropore link will cause the displacement of stored water into a pathway further downslope.
Q11. What is the main driver for interest in preferential flows and macropores in soils?
As noted earlier one of the primary drivers for interest in preferential flows and macropores in soils was the problem of explaining how pesticides and other sorbing pollutants were being transported to field drains, groundwaters and rivers [Flury, 1996].
Q12. What are the issues in developing an adequate theory to represent water flow in soils with preferential?
The issues in developing an adequate theory to representingwater flow in soils with preferential flow are those of the three functional requirements set out above, in this case for flows dominated by gravity and viscosity rather than capillarity effects.
Q13. What is the main reason why preferential flows are important at the hillslope scale?
It might be difficult to extend knowledge at the hillslope scale to larger catchment scales because of the variability of responses in space and time and the potential for deeper flow pathways to become more significant at the catchment scale [Uchida et al., 2005b; Tromp-van Meerveld et al., 2007; Bachmair and Weiler, 2013].