Connectivity: an emerging issue

Antonio Jordán (University of Seville, Spain)
Paulo Pereira (Mykolas Romeris University, Lithuania)
Saskia Keesstra (Wageningen University, The Netherlands)
Artemi Cerdà (University of Valencia, Spain)


Sin título9

What is connectivity?

Over the recent decades, a growing number of studies have highlighted the role of hydrological and sediment connectivity processes in relation to watershed management, topography, aspect, soil erosion (Bracken and Croke, 2007; Heckmann et al., 2010; Hopp and Mc Donnell, 2009; Parsons et al., 2996), movement of nutrients and pollutants (Keesstra et al., 2012a; Puttock et al., 2013; Okin and Gillette, 2001; Turnbull et al., 2011), vegetation (Jordán et al., 2008) or infrastructures (Jordán and Martínez-Zavala, 2008; Müeller et al., 2008; Ocampo et al. 2006). Water and sediment connectivity has emerged as a significant conceptual framework for understanding the transfer of surface water and sediment and associated substances through landscapes. With “connectivity”, we make reference to the interdependence of hydrological processes with other elements of the landscape as soil, highlighting the strong relationship among them. This relation occurs spatially at different scales (Bracken et al., 2014; Wainwright et al., 2011), from molecular to landscape processes through intermediate scales as aggregates, pedons or landforms(Brown et al., 2009; Dosseto et al., 2010; Harvey, 2002; Fryirs et al., 2007; Hooke, 2003; Lane et al., 2008; Jain and Tandon, 2010), and in a time-dependent way (Benda and Dunne, 1997; Harvey, 2002; McGuire and McDonnell, 2007; Otto et al., 2009). Continue reading


Connecting European connectivity research (COST Action ES1306)

Saskia Keesstra
Deputy President of the Soil System Sciences Division of the European Geosciences Union

Why connecting connectivity research?

Successful prediction of pathways of storm runoff generation and associated soil erosion is of considerable societal importance, including off-site impacts such as water quality and the provision of related ecosystem services. Recently, the role of connectivity in controlling runoff and erosion has received significant and increasing scientific attention, though in a disparate and uncoordinated way. There is a wealth of experience and expertise in connectivity across Europe that can move forward research along agreed lines and identify emerging goals, and to benefit from cross-fertilization of ideas from the fields of Hydrology, Soil Science, Geomorphology and Ecology.

The key benefit of this COST Action (ES1306) will therefore be to establish connectivity as a research paradigm. The Action will then permit transfer of current understanding into useable science, by developing its conceptual basis and transferring it into a series of monitoring and modelling tools that will provide the platform for indices that will inform holistic management of catchment systems.

Working groups and activities

The Action has five working groups focussing on different aspects of Connectivity research: WG1: Theory, WG2: Measuring Approaches, WG3: Modelling Approaches, WG4: Indices and WG5: Transfer to Management.

The first scientific meeting of the CONNECTEUR group was held in Wageningen in August 2014 (24-25-26th). In this kickoff meeting we focused on setting the agenda for the coming 4 years in which the Action will run. Apart from several keynotes addressed to introduce the different working group aims, objectives and actions, there were people from outside of science that gave their view on the connectivity concept and shared with us the way this topic is viewed and approached by policy makers and end users. In this way we tried to link science and end-users communities to find common language and create an interactive atmosphere. In addition, we got to know each other, and each other’s work. Which is of course essential for collaboration. In the program there will be ample time to look at each other’s posters and discuss possible linkages and set up new synergies. In addition we discussed in breakout groups the view on the connectivity topic in different parts of Europe and finally the way we should move forward with this science in the different working groups.

If you are interested in the outcomes of the Action and in specific the outcomes of the meeting in Wageningen check out the CONNECTEUR website.

If you want to join the Action you can register at the website and you can be as active as you like!

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This post has been also published in the EGU Blog Network.

Monday paper: Hydrological modelling of a slope covered with shallow pyroclastic deposits from field monitoring data

R. Greco, L. Comegna, E. Damiano, A. Guida, L. Olivares and L. Picarelli. Hydrological modelling of a slope covered with shallow pyroclastic deposits from field monitoring data. Hydrol. Earth Syst. Sci., 17, 4001-4013, 2013, doi: 10.5194/hess-17-4001-2013


A one-dimensional hydrological model of a slope covered with pyroclastic materials is proposed. The soil cover is constituted by layers of loose volcanic ashes and pumices, with a total thickness between 1.8 m and 2.5 m, lying upon a fractured limestone bedrock. The mean inclination of the slope is around 40°, slightly larger than the friction angle of the ashes. Thus, the equilibrium of the slope, significantly affected by the cohesive contribution exerted by soil suction in unsaturated conditions, may be altered by rainfall infiltration. The model assumes a single homogeneous soil layer occupying the entire depth of the cover, and takes into account seasonally variable canopy interception of precipitation and root water uptake by vegetation, mainly constituted by deciduous chestnut woods with a dense underbrush growing during late spring and summer. The bottom boundary condition links water potential at the soil–bedrock interface with the fluctuations of the water table of the aquifer located in the fractured limestone, which is conceptually modelled as a linear reservoir. Most of the model parameters have been assigned according to literature indications or from experimental data. Soil suction and water content data measured between 1 January 2011 and 20 July 2011 at a monitoring station installed along the slope allowed the remaining parameters to be identified. The calibrated model, which reproduced very closely the data of the calibration set, has been applied to the simulation of the hydrological response of the slope to the hourly precipitation record of 1999, when a large flow-like landslide was triggered close to the monitored location. The simulation results show that the lowest soil suction ever attained occurred just at the time the landslide was triggered, indicating that the model is capable of predicting slope failure conditions.

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Hydrology and Earth System Sciences (HESS) is an international two-stage open access journal for the publication of original research in hydrology, placed within a holistic Earth System Science context. The discussion and peer-review of submitted papers are handled in the open access discussion journal HESSD. Final papers, upon acceptance, appear in HESS (see Review Process under the heading Review).

HESS encourages and supports fundamental and applied research that seeks to understand the interactions between water, earth, ecosystems and man. A multi-disciplinary approach is encouraged that enables a broadening of the hydrologic perspective and the advancement of hydrologic science through the integration with other cognate sciences, and the cross-fertilization across disciplinary boundaries. HESS, therefore, has the ambition to serve not only the community of hydrologists, but all earth and life scientists, water engineers and water managers, who wish to publish original findings on the interactions between hydrological processes and other physical, chemical, biological and societal processes within the earth system, and the utilization of this holistic understanding towards sustainable management of water resources, water quality and water-related natural hazards.

The scope of HESS therefore encompasses:

  1. The role of physical, chemical and biological processes in the cycling of continental water in all its phases, including dissolved and particulate matter, at all scales, from the micro-scale processes of soil water to the global-scale processes underpinning hydro-climatology.
  2. The study of the spatial and temporal characteristics of the global water resources (solid, liquid and vapour) and related budgets, in all compartments of the Earth System (atmosphere, oceans, estuaries, rivers, lakes and land masses), including water stocks, residence times, interfacial fluxes, and the pathways between various compartments.
  3. The study of the interactions with human activity of all the processes, budgets, fluxes and pathways as outlined above, and the options for influencing them in a sustainable manner, particularly in relation to floods, droughts, desertification, land degradation, eutrophication, and other aspects of global change.

The journal will publish research articles, research and technical notes, opinion papers, book reviews, brief communications, and comments on papers published previously in HESS. Papers can address different techniques and approaches, including: theory, modelling, experiments or instrumentation. The journal covers the following Subject Areas and Techniques/Approaches, which are used to categorise papers:

Subject Areas:

  • Hillslope Hydrology;
  • Catchment Hydrology;
  • Global Hydrology;
  • Rivers and Lakes;
  • Coasts and Estuaries;
  • Hydrometeorology;
  • Vadose Zone Hydrology;
  • Groundwater Hydrology;
  • Ecohydrology;
  • Biogeochemical Processes;
  • Urban Hydrology;
  • Engineering Hydrology;
  • Water Resources Management.

Techniques and Approaches:

  • Theory Development;
  • Modelling Approaches;
  • Instruments and Observation Techniques;
  • Remote Sensing and GIS;
  • Mathematical Applications;
  • Stochastic Approaches;
  • Uncertainty Analysis.

More at Hydrology and Earth System Sciences homepage

Impact of fires on soil properties, runoff generation and sediment transport

Notes on session Session SSS 9.6/GM 6.7/HS 12.6 (EGU2013)

Conveners: Lee MacDonald; Jonay Neris; Stefan Doerr; Artemi Cerdà; J. Jacob Keizer

Wildfires are increasingly recognized as the primary cause of geomorphic change in forests and brush lands, and climate change is expected to further increase both the amount and severity of wildfires. Recent studies have provided an increasing amount of data on how fires can affect runoff and erosion rates, but there is still much to be done on the underlying causes of the observed increases, and how fire affects vary across vegetation types, climates, and spatial scale.

Post-wildfire landscape.
Post-wildfire landscape.

Dr. Scott Woods at the University of Montana was taking a leading role in this process-based research until his career was tragically ended by lung cancer. The Soil System Science sponsored a session in his honor during the 2013 EGU meeting, and this was entitled Impact of fires on soil properties, runoff generation and sediment transport.  The main aim of this session was to discuss the recent studies on the effects of fires on soil properties, the resultant changes in runoff and erosion rates, and the effectiveness of different post-fire treatments to mitigate these effects.

Impact of fires on soil properties, runoff generation and sediment transport oral session.
Impact of fires on soil properties, runoff generation and sediment transport oral session.

Twenty-four papers were submitted to this session.  The morning oral session in the morning began with a brief summary of Scott’s career, and this was followed by eight talks.  The session then shifted to a different room where a series of short presentations summarized many of the 16 poster papers.    The afternoon poster session then provided a lively venue for further discussions, and in the evening many of the presenters attended the special dinner for all those working on topics related to soil erosion.  Discussions are being held regarding the possible publication of the papers in a special issue of a peer-reviewed journal.

Earth System Dynamics: Entropy production of soil hydrological processes and its maximisation

Porada, P., Kleidon, A., and Schymanski, S. J.: Entropy production of soil hydrological processes and its maximisation, Earth Syst. Dynam., 2, 179-190, doi:10.5194/esd-2-179-2011, 2011.


Large areas of land are restored with unweathered soil substrates following mining activities in eastern Germany and elsewhere. In the initial stages of colonization of such land by vegetation, plant roots may become key agents in generating soil formation patterns by introducing gradients in chemical and physical soil properties. On the other hand, such patterns may be influenced by root growth responses to pre-existing substrate heterogeneities. In particular, the roots of many plants were found to preferentially proliferate into nutrient-rich patches. Phosphorus (P) is of primary interest in this respect because its availability is often low in unweathered soils, limiting especially the growth of leguminous plants. However, leguminous plants occur frequently among the pioneer plant species on such soils, as they only depend on atmospheric nitrogen (N) fixation as N source. In this study we investigated the relationship between root growth allocation of the legume Lotus corniculatus and soil P distribution on recently restored land. As test sites, the experimental Chicken Creek Catchment (CCC) in eastern Germany and a nearby experimental site (ES) with the same soil substrate were used. We established two experiments with constructed heterogeneity, one in the field on the experimental site and the other in a climate chamber. In addition, we conducted high-density samplings on undisturbed soil plots colonized by L. corniculatus on the ES and on the CCC. In the field experiment, we installed cylindrical ingrowth soil cores (4.5 × 10 cm) with and without P fertilization around single two-month-old L. corniculatus plants. Roots showed preferential growth into the P-fertilized ingrowth-cores. Preferential root allocation was also found in the climate chamber experiment, where single L. corniculatus plants were grown in containers filled with ES soil and where a lateral portion of the containers was additionally supplied with a range of different P concentrations. In the high-density samplings, we excavated soil-cubes of 10 × 10 × 10 cm size from the topsoil of 3 mini-plot areas (50 × 50 cm) each on the ES and the CCC on which L. corniculatus had been planted (ES) or occurred spontaneously (CCC) and for each cube separated the soil attached to the roots (root-adjacent soil) from the remaining soil (root-distant soil). Root length density was negatively correlated with labile P (resin-extractable P) in the root-distant soil of the CCC plots and with water-soluble P in the root-distant soil of the ES plots. The results suggest that P depletion by root uptake during plant growth soon overrode the effect of preferential root allocation in the relationship between root density and plant-available soil P heterogeneity.

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Earth System Dynamics (ESD) is an international scientific journal dedicated to the publication and public discussion of studies that take an interdisciplinary perspective of the functioning of the whole Earth system and global change. The overall behavior of the Earth system is strongly shaped by the interactions among its various component systems, such as the atmosphere, cryosphere, hydrosphere, oceans, pedosphere, lithosphere, and the inner Earth, but also by life and human activity. ESD solicits contributions that investigate these various interactions and the underlying mechanisms, ways how these can be conceptualized, modelled, and quantified, predictions of the overall system behavior to global changes, and the impacts for its habitability, humanity, and future Earth system management by human decision making. More at Earth System Dynamics homepage.

John Freeland: protecting our soil and natural resources

John Freeland                                                                                                               Environmental and Soil Scientist, Michigan USA

When I was seven years old, my family moved from Dearborn, a modern suburb of Detroit, Michigan and the home of Henry Ford, to a much smaller and older town in Northwest Ohio, called Defiance. Perhaps the most notable aspect of Defiance was that it was built at the (confluence of the Maumee and Auglaize rivers) and regional folklore had it that the meeting of these two rivers protected the town from tornadoes. Twisters were common in the flat corn country surrounding Defiance, but the town never suffered a direct hit. Continue reading