Progress in gully erosion research: IV International Symposium on Gully Erosion

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Open Access
Waterfall erosion as a main factor in ephemeral gully initiation in a part of Northeastern Iran
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Sadeghi, S.H.R.; Rangavar, A.S.; Bashari, M.; Abbasi, A.A.
The present study assesses the factors controlling gully formation in a study area located in northeastern Iran. Gully erosion in northeastern Iran is very high because of the high rate of human encroachment and the resulting impacts on soil erosion.
Open Access
Scouring-sedimentation balance for gully reaches affected by check dams in Mediterranean environments
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Conesa García, C.; García Lorenzo, R.
Many of the geomorphological impacts caused by check dams are usually fairly common in torrential channels (bed agradation upstream into the sedimentary wedges, deepening and narrowing of the bankfull channel downstream, etc). Nevertheless, the extent of these impacts and consequently the degree of effectiveness of the crossstructures is very different depending on the environmental characteristics of the catchments and on the hydrological rectification systems (spatial distribution of check dams, location, number and type of work). A clear indicator of such an influence is the channel response to the deficit and overfeeding of sediments (Brandt, 2000; Lenzi et al., 2003; Marion et al., 2006; Comiti et al., 2005). In such a way, this study has as its objective to show the influence of staggered check dams of gabions on the scouring-sedi-mentation balance in Mediterranean ephemeral gullies submitted to Projects of Hydrological Forest Restoration (PHFR). For areas of study, two semiarid gullied catchments with a strong tendency to dry up have been chosen: Torrecilla and Cárcavo catchments (South-east Spain). The Torrecilla catchment (15.5 km2) shows a gullied area develo-ped on metamorphic materials (slates, phyllites, schists and quartzites), while the Cárcavo catchment (34.8 km2) is drained by ephemeral channels and gullies that dissect deeply the Miocene marls and Quaternary pediments. The hydrological rectification projects undertaken are similar in both catchments: 33 and 40 check dam series were constructed respectively during the 1970s, the majority of them with gabions.
Open Access
Ephemeral gully erosion research: processes and modeling
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Alonso, C.V.
The USDA Natural Resources Conservation Service (NRCS) defines ephemeral gullies as small channels that can be filled in by normal tillage operations only to reform in the same location by subsequent runoff events. Ephemeral gullies contribute significantly to soil erosion in agricultural fields, and NRCS has consistently identified gully erosion as their number one problem to solve. Moreover, headcut development and migration is closely coupled to the initiation of ephemeral gullies and their extension on hillslopes. Research is needed to further understand the physics of these processes, to derive robust predictive algorithms and methodologies, and to develop reliable control methods.
Open Access
Gully erosion in central Italy: denudation rate estimation and morphoevolution of Calanchi and Biancane badlands
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Della Seta, M.; Del Monte, M.; Fredi, P.; Lupia Palmieri, E.
Long lasting geomorphological researches (Ciccaci et al., 1981, 1986, 2003; Del Monte et al., 2006) allowed the evaluation of denudation rates in some of the major catchments of Central Italy. It was observed a noticeable spatial variability of the denudation index (Tu) values (Ciccaci et al., 1981, 1986) and field monitoring suggested that gully erosion at badlands is likely to afford the major contribution to overall denudation at catchments scale. This paper summarizes the original results of the last three years of researches, performed on Tevere, Paglia and Ombrone basins. By thickening field monitoring, it was evidenced as well a variability of denudation rates among sharp- and rounded-edged badlands (calanchi and biancane), according to their different morphoevolution.
Open Access
Comparison of historical evolution of gully networks on both Slovak and Moravian forelands of the white Carpathians
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Stankoviansky, M.; Létal, A.; Damankosová, Z.
The main objective of the contribution is to present the preliminary results of comparison of historical evolution of gully networks in both Slovak and Moravian forelands of the White Carpathians. This geomorphic unit represents the flysch mountain range situated in the boundary zone of Slovakia and the Czech Republic, reaching the elevation 970 m. The Slovak foreland of the White Carpathians, i.e. the Myjava Hill Land, belongs among those areas in Slovakia that were the most affected by disastrous gullying in the past. This fact was one of the main reasons to choose precisely this area for detailed investigation of historical gullies, lasting at the moment approximately one decade. The study of the Moravian foreland of the White Carpathians, i.e. Hluk Hill Land, started in 2006. Its first goal was to find out if the density of gully network on the Moravian side is comparable with that at the Slovak side. Beside the density of gully networks also the age of gullies and causes of their formation on both sides of the frontier were subjects of this comparison. Comparison of gullies on both forelands of the White Carpathians is introduced in the context of the review of the research dealing with the historical evolution of gullies in Slovakia and Czech Republic.
Open Access
Proposed methodology to quantify ephemeral gully erosion
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Huang, C.; Nouwakpo, K.; Frankenberger, J.R.
The overall objective of the proposed research is to identify and quantify landscape attributes and hydrologic conditions that can be used to assess hillslope seepage and ephemeral gully erosion. We propose to use three different methodologies to study ephemeral gully development, i.e., 1) laboratory rainfall simulation to quantify seepage and hydraulic shear effects on rill or gully initiation; 2) digital photogrammetry from low altitude aerial photography to quantify ephemeral gully development; 3) topographic threshold based ephemeral gully erosion model with subsurface hydrology.
Open Access
Concentrated flow erodibility of loess-derived topsoils: the impact of rainfall-induced consolidation and sealing
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Knapen, A.; Poesen, J.; Baets, S. de
This study investigates the impact of rainfall-induced soil consolidation and soil surface sealing processes over time after tillage on soil erosion during concentrated flow. The soil erodibility (Kc) and critical flow shear stress (τcr) were examined for identical, artificially created soil samples under simulated rainfall. As these rainfall-induced soil structural changes are inseparably related to soil moisture variations, the effects are evaluated for different soil moisture conditions.
Open Access
Gully erosion risk zoning: proposal of a methodology and case study
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Viero, A.C.; Castro, N.M.R.; Risso, A.; Goldenfun, J.A.
Gullying is the most advanced, complex stage of erosion processes, with more local destructive power than other types of erosion (São Paulo, 1990). In this paper, we propose a method to generate gully erosion risk zoning in the far south plateau of Brazil, based on geological characteristics, soils and geomorphology.
Open Access
Sidewall erosion control strategies in gullies of the Penedès – Anoia vineyard region (NE Spain)
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Martínez Casasnovas, J.A.
The objective of this work is to formulate different sidewall erosion control strategies to reduce retreat and sediment production rates in the gullies of the Penedès-Anoia (NE Spain) region.
Open Access
Improving the structural stability of cropped soils in Olite (Navarre) using conservation tillage to reduce water erosion
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Río Lahidalga, Iker del; Fernández Ugalde, Oihane; Imaz Gurruchaga, María José; Enrique Martín, Alberto; Bescansa Miquel, Paloma; Ciencias del Medio Natural; Natura Ingurunearen Zientziak
The objective of this work was to compare the soil wet aggregate stability and its relationship to the soil organic matter stock in an agricultural soil under different types of tillage in a semi-arid area of Northern Spain.
Open Access
Activity of gullies during the Holocene in the Ebro valley
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Peña, Julio; Constante, A.; Chueca, J.; Echeverría Arnedo, María Teresa; Julián, A.; Longares, L.A.
The use of detailed geomorphology for the study of the Upper Holocene and the application of geoarchaeology and radiometric datings make it possible to get important results on the recent stages of valley bottom shaping. The timing of the aggradation and degradation phases shows the activity of the processes over the last 8000 years and the decisive influence of the Holocene evolution on present landscapes. The reasons for this phase alternation are anthropoclimatic, as Jordá and Vaudour (1980), Bintliff (1981, 1982), Gutiérrez and Peña (1998) and Peña (1996), Peña et al. (2000, 2004) recognize in different sectors of the Mediterranean basin. The gullies formation and activity from the late Roman Period has progressed by means of a regressive activity of the headwaters, although the excavation process has been temporarily interrupted by new fillings.
Open Access
Impact of root architecture, soil and flow characteristics on the erosion-reducing potential of roots during concentrated flow
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Baets, S. de; Poesen, J.; Knapen, A.
In this study, the effects of roots of different root morphologies (tap roots vs. fine-branched roots) on concentrated flow erosion rates are studied experimentally. The impact of soil type, soil moisture conditions (saturated vs. dry topsoil samples) and flow shear stress on the erosion reducing effect of roots is also considered.
Open Access
Seepage erosion impacts on edge-of-field gully erosion
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Wilson, G.V.; Fox, G.A.; Chu-Agor, M.L.
Concentrated flow is generally considered the controlling mechanism for gully erosion whereas subsurface flow is often overlooked. The two mechanisms of subsurface flow attributed to gully erosion are seepage flow and preferential flow through soil-pipes. Seepage erosion typically occurs in duplex soils in which a perched water table develops above a water-restricting horizon. The effect of seepage is usually considered to be limited to the production of surface runoff and the impact of increasing soil water pressures on reducing soil shear strength. However, recent studies by Wilson et al. (2007), Fox et al (2006, 2007), and Chu-Agar et al. (2007) have demonstrated that seepage erosion can be the controlling process of streambank failure and by analogy may be a significant contributor to gully erosion. Seepage erosion is used to describe the process of sediment transport out of the gully face by liquefaction of soil particles entrained in the seepage. The undercutting of the gully face by seepage erosion results in bank failure which may be a contributing factor to headcut migration and gully widening. This paper will review this recent work on seepage erosion.
Open Access
Gully erosion in mountain area of SW-China, assessed using 137Cs and 210PBEX tracers and GPS survey
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Li, Y.; Poesen, J.; Liu, L. M.; Li, L.; He, F. H.; Zhang, Q. W.; Li, R.
Gullies are extensively distributed in the Upper Yangtze River Basin, SW-China. But the impact of these gullies on total sediment output is still not clear because there is no reliable technique for quantifying this issue. The target areas of our research are the dry-valleys located in the upper Yangtze River Basin, SW-China. Our study objectives are to: a) quantify gully erosion rates as affected by land use change over the last 100 years, and b) to assess relative importance of different erosion types including gully and rill or sheet erosion in sediment production in selected gully catchments.
Open Access
Implications of recent experimental findings for rill erosion modeling
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Govers, G.; Giménez Díaz, Rafael; Van Oost, K.; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
The major aim of this paper is to critically review the theoretical concepts that are underpinning current models of rill flow and sediment detachment in the light of recent experimental results and, when necessary, to propose modifications to the theoretical formulations so that they are in agreement with experimental evidence. We also investigate to what extent a detachment model of reduced complexity, which is based on experimental observations, is consistent with field observation on the effect of topography on rill erosion.
Open Access
Runoff and sediment supply from small gullied and ungullied basins in a semi-arid grazed environment
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Chocron, M.; Laronne, J.B.; Alexandrov, Y.
The aim of the present study is to determine links between rainfall, runoff, gully erosion and sediments. The extent of sediment yield (suspended sediment and bedload) and runoff response from gullied and ungullied basins have been explored. The outcomes of this study are discussed in the context of spatial and temporal scales.
Open Access
AnnAGNPS ephemeral gully erosion simulation technology
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Bingner, R.L.; Theurer, F.D.; Gordon, L.M.; Bennett, S.J.; Parker, C.; Thorne, C.; Alonso, C.V.
Tillage-induced ephemeral gully erosion has been shown to be a significant and sometimes dominant source of sediment within a watershed. An approach has been developed within AnnAGNPS to assess the impact of conservation practices on ephemeral gully erosion as well as sheet and rill erosion. Conservation management treatments should include targeting practices specific for ephemeral gullies differently than for sheet and rill erosion. Within watersheds, gullies are becoming the dominate source of cropland erosion unless preventative conservation practices are installed.
Open Access
Effect of topography on retreat rate of different gully headcuts in Bardenas Reales area (Navarre, Spain)
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Campo-Bescós, Miguel; Álvarez-Mozos, Jesús; Casalí Sarasíbar, Javier; Giménez Díaz, Rafael; Proyectos e Ingeniería Rural; Landa Ingeniaritza eta Proiektuak
In Northeast Spain, gullying is a widespread phenomenon. This type of erosion is especially intense in Bardenas Reales (Navarre) where at least two major typical kinds of gully headcut are present. A first group developed in soil material (named, conventional gully headcut), and second group of gully headcut with a sandstone layer as a top horizon (named, sandstone gully headcut). In addition, within the former group, we can distinguish a subgroup of gully headcuts developed in soils particularly prone to piping and tunnelling due to the dispersive condition of the materials (named piping associated gully headcut). In this situation, a question arises: to what extent simple topographic parameters account for the retreat rate of the different kind of gully headcuts observed in the region of Bardenas Reales? The aim of this study was to investigate and gain insight in this issue.
Open Access
Modelling the occurrence of gullies in semi-arid areas of south-west Spain
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Gómez Gutiérrez, Á.; Schnabel, Susanne; Felicísimo, A.
Modern predictive models represent a powerful tool for predicting and analyzing geomorphological phenomena like gullying. The model obtained presents a high percentage of success in classifying gullied and ungullied areas. Nevertheless, in some areas the prediction of the occurrence of gullying was worse. Further studies need to be carried out in order to understand the reasons for its poor performance in certain areas. However, an improved model could be an important management and planning tool for silvopastoral areas of southwest Spain.
Open Access
Ephemeral gullies: to till or not to till?
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2007) Gordon, L.M.; Bennett, S.J.; Alonso, C.V.; Bingner, R.L.
While the perceived magnitude of ephemeral gully erosion may be masked after gullies are repaired, the action of plowing in these channels reduces topsoil thickness and crop productivity over a much wider area than the channel itself. This study demonstrates that filling ephemeral gullies on an annual basis during tillage operations may be more destructive than realized. These results should provide land managers an additional incentive for adopting soil conservation practices such as no-till.