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This study investigates potential effects of wetland restoration on storm flow dynamics in a mainly waterlogged low mountain range catchment located in SW-Germany. Here, wetland drainage networks are being sealed, aiming to achieve rising soil water tables and reestablished peat vegetation. With the help of hydrograph separation, multiple linear regression (MLR) and covariance analysis (ANCOVA), runoff-governing storm properties and sealing influences were analyzed. Results show, that not only natural storm parameters (precipitation sum, rainfall intensity, antecedent precipitation and temperature) exert influence on storm-runoff, but sealings also led to significantly altered processes: On the one hand, storm-runoff coefficients increased in sealed catchments, resulting most likely from more saturated soils, providing a smaller infiltration capacity. This is a desired effect of rewetting but coincidently a downside regarding storm flood prevention. On the other hand, lag times, meaning the timespan between rainfall occurrence and the hydrograph starting to rise, were noticeably prolonged. This effect can be potentially beneficial when it comes to storm flood prevention. Overall, statistical models including sealings showed more satisfactory results describing stormflow variance compared to models without sealings. Therefore, sealings do exert – statistically proven – an effect on storm runoff. The heterogeneity of the results, representing a dense gauge network spread over an investigation area of roughly 7.5 km² shows, that a high-resolution sampling, both spatially and temporally, is vital. That is since runoff processes in waterlogged low mountain range catchments are still poorly understood.
Julian Zemke. Storm-runoff processes in a mainly waterlogged low mountain range catchment in the national park Hunsrück-Hochwald, SW-Germany. 2021, 1 .
AMA StyleJulian Zemke. Storm-runoff processes in a mainly waterlogged low mountain range catchment in the national park Hunsrück-Hochwald, SW-Germany. . 2021; ():1.
Chicago/Turabian StyleJulian Zemke. 2021. "Storm-runoff processes in a mainly waterlogged low mountain range catchment in the national park Hunsrück-Hochwald, SW-Germany." , no. : 1.
This study investigates potential effects of wetland restoration on storm flow dynamics in a mainly waterlogged low mountain range catchment located in SW-Germany. Here, wetland drainage networks are being sealed, aiming to achieve rising soil water tables and reestablished peat vegetation. With the help of hydrograph separation, multiple linear regression (MLR) and covariance analysis (ANCOVA), runoff-governing storm properties and sealing influences were analyzed. Results show, that not only natural storm parameters (precipitation sum, rainfall intensity, antecedent precipitation and temperature) exert influence on storm-runoff, but sealings also led to significantly altered processes: On the one hand, storm-runoff coefficients increased in sealed catchments, resulting most likely from more saturated soils, providing a smaller infiltration capacity. This is a desired effect of rewetting but coincidently a downside regarding storm flood prevention. On the other hand, lag times, meaning the timespan between rainfall occurrence and the hydrograph starting to rise, were noticeably prolonged. This effect potentially can be beneficial when it comes to storm flood prevention. Overall, statistical models including sealings showed more satisfactory results describing stormflow variance compared to models without sealings. Therefore, sealings do exert – statistically proven – an effect on storm runoff. The heterogeneity of the results, representing a dense gauge network spread over an investigation area of roughly 7.5 km² shows, that a high-resolution sampling, both spatially and temporally, is vital. That is since runoff processes in waterlogged low mountain range catchments are still poorly understood.
Julian Zemke. Storm-runoff processes in a mainly waterlogged low mountain range catchment in the national park Hunsrück-Hochwald, SW-Germany: Assessing the impact of wetland restoration using multiple linear regression analysis and ANCOVA. 2020, 1 .
AMA StyleJulian Zemke. Storm-runoff processes in a mainly waterlogged low mountain range catchment in the national park Hunsrück-Hochwald, SW-Germany: Assessing the impact of wetland restoration using multiple linear regression analysis and ANCOVA. . 2020; ():1.
Chicago/Turabian StyleJulian Zemke. 2020. "Storm-runoff processes in a mainly waterlogged low mountain range catchment in the national park Hunsrück-Hochwald, SW-Germany: Assessing the impact of wetland restoration using multiple linear regression analysis and ANCOVA." , no. : 1.
This study discusses penetration resistance (PR) of forested Pumice-Andosol sites. PR, a key soil property influencing root growth and elongation, exerts a substantial influence on ecological site quality and tree growth. Andosols were expected to show low PR because of their unique characteristics (low bulk density, loose soil matrix). Five sites, two undisturbed and three backfilled, were sampled. The latter result from pumice excavation and were examined to quantify potential PR alterations in the aftermath of backfilling and pumice removal. Penetrologger sampling on undisturbed sites showed mean PR not exceeding 3 MPa, a literature-based, critical threshold restricting root growth, in the upper 0.80 m, indicating conditions fostering tree rooting. Backfilled sites mostly exhibited increased (> 3 MPa) PR, leading to rooting restrictions even beginning at −0.21 m. Deviations from undisturbed soils range from −15.6 to +109.3% depending on depth and age of the backfilled site. Furthermore, GIS-based data interpolation helped to identify spatial PR patterns and allowed a direct comparison before/after backfilling at one site. Statistical analysis revealed significantly altered PR after backfilling, while a concluding ANOVA provided at least significant governing factors (depth, area, clay + silt content, soil organic matter), albeit with only small effect sizes.
Julian J. Zemke; Ulli Bange; John Dellen; Ines Groh; Roxane C. A. Henn; Joshua Pöhler; Stephan Stegmann. Penetration Resistance of Laacher See-tephra Andosols—Evaluating Rooting Conditions of Undisturbed and Excavated Forest Soils in SW-Germany. Forests 2020, 11, 360 .
AMA StyleJulian J. Zemke, Ulli Bange, John Dellen, Ines Groh, Roxane C. A. Henn, Joshua Pöhler, Stephan Stegmann. Penetration Resistance of Laacher See-tephra Andosols—Evaluating Rooting Conditions of Undisturbed and Excavated Forest Soils in SW-Germany. Forests. 2020; 11 (3):360.
Chicago/Turabian StyleJulian J. Zemke; Ulli Bange; John Dellen; Ines Groh; Roxane C. A. Henn; Joshua Pöhler; Stephan Stegmann. 2020. "Penetration Resistance of Laacher See-tephra Andosols—Evaluating Rooting Conditions of Undisturbed and Excavated Forest Soils in SW-Germany." Forests 11, no. 3: 360.
This study investigates the effects of pumice excavation on runoff formation and soil erosion processes in a forested catchment in SW-Germany. The underlying questions are, if (a) backfilled soils have different properties concerning runoff generation and erodibility and if (b) clear-cutting prior to excavation triggers runoff and erosion. Four adjacent sub-areas were observed, which represented different pre- and post-excavation-stages. The basis of the investigation was a comprehensive field sampling that delivered the data for physical erosion modeling using the Water Erosion Prediction Project (WEPP). Modeling took place for standardized conditions (uniform slope geometry and/or uniform land management) and for actual slope geometry and land management. The results show that backfilled soils exhibited 53% increase of annual runoff and 70% increase of annual soil loss under standardized conditions. Storm runoff was increased by 6%, while storm soil loss was reduced by 9%. Land management changes also triggered shifts in annual runoff and soil erosion: Clear-cut (+1.796% runoff, +4.205% soil loss) and bare (+5.958% runoff, +21.055% soil loss) surfaces showed the most distinct changes when compared to undisturbed forest. While reforestation largely diminished post-excavation runoff and soil erosion, the standardized results statistically prove that soil erodibility and runoff generation remain increased after backfilling.
Julian J. Zemke; Joshua Pöhler; Stephan Stegmann. Modeling Runoff-Formation and Soil Erosion after Pumice Excavation at Forested Andosol-Sites in SW-Germany Using WEPP. Soil Systems 2019, 3, 48 .
AMA StyleJulian J. Zemke, Joshua Pöhler, Stephan Stegmann. Modeling Runoff-Formation and Soil Erosion after Pumice Excavation at Forested Andosol-Sites in SW-Germany Using WEPP. Soil Systems. 2019; 3 (3):48.
Chicago/Turabian StyleJulian J. Zemke; Joshua Pöhler; Stephan Stegmann. 2019. "Modeling Runoff-Formation and Soil Erosion after Pumice Excavation at Forested Andosol-Sites in SW-Germany Using WEPP." Soil Systems 3, no. 3: 48.
This study discusses the influence of soil compaction on runoff generation with a special focus on forested Andosol sites. Because of their typical soil physical characteristics (low bulk density, high pore volumes) and the existent land use, these areas are expected to show low to no measurable overland flow during heavy rainfall events. However, due to heavy machinery traffic in the course of forestry actions and pumice excavations, skid trails have been established. Here, a distinct shift of soil dry bulk density (DBD) was observable, using a detailed soil mapping and data interpolation in order to generate in-depth DBD-cross profiles. Additionally, infiltration measurements and rainfall simulations (I = 45 mm·h−1, t = 30 min) were conducted to evaluate effects of observed soil compaction on infiltration rates and overland flow formation. Results show that soil compaction was increased by 21% on average in skid trail wheel ruts. As a consequence, observed runoff was 8.5-times higher on skid trails, while saturated hydraulic conductivity was diminished by 36%. These findings show, that soil compaction leads to a higher possibility of runoff formation during heavy rainfall events, especially at sites which showed initial conditions with presumably low tendencies of runoff formation.
Julian J. Zemke; Michel Enderling; Alexander Klein; Marc Skubski. The Influence of Soil Compaction on Runoff Formation. A Case Study Focusing on Skid Trails at Forested Andosol Sites. Geosciences 2019, 9, 204 .
AMA StyleJulian J. Zemke, Michel Enderling, Alexander Klein, Marc Skubski. The Influence of Soil Compaction on Runoff Formation. A Case Study Focusing on Skid Trails at Forested Andosol Sites. Geosciences. 2019; 9 (5):204.
Chicago/Turabian StyleJulian J. Zemke; Michel Enderling; Alexander Klein; Marc Skubski. 2019. "The Influence of Soil Compaction on Runoff Formation. A Case Study Focusing on Skid Trails at Forested Andosol Sites." Geosciences 9, no. 5: 204.
A portable rainfall simulator was built for assessing runoff and soil erosion processes at interrill scale. Within this study, requirements and constraints of the rainfall simulator are identified and discussed. The focus lies on the calibration of the simulator with regard to spatial rainfall homogeneity, rainfall intensity, drop size, drop fall velocity and rainfall kinetic energy. These parameters were obtained using different methods including a Laser Precipitation Monitor. A detailed presentation of the operational characteristics is given. The presented rainfall simulator setup featured a rainfall intensity of 45.4 mm·h-1 with a spatial homogeneity of 80.4% based on a plot area of 0.64 m². Because of the comparatively low drop height (2 m), the diameter-dependent terminal fall velocity (1.87 m·s-1) was lower than benchmark values for natural rainfall. This conditioned also a reduced rainfall kinetic energy (4.6 J·m-2·mm-1) compared to natural rainfall with same intensity. These shortfalls, a common phenomenon concerning portable rainfall simulators, represented the best possible trade-off between all relevant rainfall parameters obtained with the given simulator setup. Field experiments proved that the rainfall erosivity was constant and replicable.
Julian Zemke. Set-up and calibration of a portable small scale rainfall simulator for assessing soil erosion processes at interrill scale. Cuadernos de Investigación Geográfica 2017, 43, 63 .
AMA StyleJulian Zemke. Set-up and calibration of a portable small scale rainfall simulator for assessing soil erosion processes at interrill scale. Cuadernos de Investigación Geográfica. 2017; 43 (1):63.
Chicago/Turabian StyleJulian Zemke. 2017. "Set-up and calibration of a portable small scale rainfall simulator for assessing soil erosion processes at interrill scale." Cuadernos de Investigación Geográfica 43, no. 1: 63.
Forestry operations can significantly alter hydrological and erosional processes in a catchment. In the course of developing timberland, a network of persistent roads and skid trails causing soil compaction is usually established. Hereby, the infiltration rate of the soil is distinctly reduced, which leads to the generation of overland flow—this may also cause soil erosion. In this study, a small-scale rainfall simulator is used to investigate hydrological and erosional processes on forest roads and skid trails. The results show increased runoff rates on forest roads, up to 25 times higher than on undisturbed forest topsoil. On skid trails, the runoff rates were altered especially in rutted areas (16 times higher) while unrutted parts showed a lesser change (four times higher). With sufficient overland flow, soil erosion rates also rose, particularly when the vegetation cover of the surface was removed: bare road surfaces featured higher mean erosion rates (195 g·m−2) than partly or completely vegetated skid trails (13 g·m−2) and undisturbed sites (5 g·m−2). The findings presented in this study indicate the need for the use of compaction reducing technology during forestry operations and a revegetation of road surfaces in order to minimize the detrimental factor of roads and skid trails on water retention and soil conservation.
Julian J. Zemke. Runoff and Soil Erosion Assessment on Forest Roads Using a Small Scale Rainfall Simulator. Hydrology 2016, 3, 25 .
AMA StyleJulian J. Zemke. Runoff and Soil Erosion Assessment on Forest Roads Using a Small Scale Rainfall Simulator. Hydrology. 2016; 3 (3):25.
Chicago/Turabian StyleJulian J. Zemke. 2016. "Runoff and Soil Erosion Assessment on Forest Roads Using a Small Scale Rainfall Simulator." Hydrology 3, no. 3: 25.
The role of solitary woody riparian plants with respect to local erosion and deposition of sediments is investigated. A focus is laid on the characteristics ‘inclination’ and ‘permeability’ of the plant's projected frontal area. Therefore, two experimental studies using cylindrical obstacles were carried out in a laboratory flume, one aiming at inclination, the other at permeability. The first series revealed that the total amount of mobilized sediment around the cylinder on average decreased by 8–10% per 5° increasing inclination in streamwise direction. Locations of maximum scour depth simultaneously shifted downstream. A horseshoe vortex system, causing the frontal and lateral scouring, ceased to exist below inclinations of 25–30°. The second series revealed that with increasing permeability, frontal scour incision is delayed, and the eroded sediment volume is significantly reduced. With permeable obstacles, two system states were observed: first, frontal scouring with leeside deposition at higher flow velocities and, second, moderate leeside scouring at lower flow velocities. For up‐scaling and comparison, a field study focussing on fluvial obstacle marks at poplars and willows in secondary channels of the River Loire was additionally conducted. A modified analytical model enabled us to quantify the amount of deposited sediments leeside of the plants. Leeside sediment ridges are significantly stabilized and have a higher preservation potential when covered by pioneer vegetation. Under such conditions, they may indeed induce the development of stable islands. Eventually, ‘sediment ridge width’ turned out to be a suitable indicator for leeside deposited sediment volume, irrespective of spatial scale. Copyright © 2012 John Wiley & Sons, Ltd.
Thomas Euler; Julian Zemke; Stéphane Rodrigues; Jürgen Herget. Influence of inclination and permeability of solitary woody riparian plants on local hydraulic and sedimentary processes. Hydrological Processes 2013, 28, 1358 -1371.
AMA StyleThomas Euler, Julian Zemke, Stéphane Rodrigues, Jürgen Herget. Influence of inclination and permeability of solitary woody riparian plants on local hydraulic and sedimentary processes. Hydrological Processes. 2013; 28 (3):1358-1371.
Chicago/Turabian StyleThomas Euler; Julian Zemke; Stéphane Rodrigues; Jürgen Herget. 2013. "Influence of inclination and permeability of solitary woody riparian plants on local hydraulic and sedimentary processes." Hydrological Processes 28, no. 3: 1358-1371.
Pleistocene megafloods generated several large-scale obstacle marks that could not be interpreted hydraulically with the present knowledge of submerged obstacles. Thus, flume and field data of classical obstacle marks, characterised by a frontal scour hole and an adjacent depositional ridge, are analysed to estimate flow velocities from obstacle mark geometry, especially scour depths, length, width and ridge width. These data reveal a consistency of correlations between obstacle mark morphometries across a wide spatial scale. Two existing analytical models, basically integrating obstacle size, flow velocity as well as sediment size and grading, are transformed so that the magnitude of individual geometric parameters can be used as variables for the estimation of mean and tip flow velocities. These reconstructed velocities have to be regarded as minimum velocities during the rising limb of the hydrograph, as peak discharge might not last long enough to significantly influence the obstacle mark dimensions. A universally applicable practical outline is developed for palaeohydraulic reconstruction. This framework is applied on three examples of obstacle marks generated by Pleistocene megafloods. The reliability and scale-invariance of these reconstructions is confirmed by similar results of velocity estimations by other independent approaches at the same locations.
Jürgen Herget; Thomas Euler; Thomas Roggenkamp; Julian Zemke. Obstacle marks as palaeohydraulic indicators of Pleistocene megafloods. Water Policy 2012, 44, 300 -317.
AMA StyleJürgen Herget, Thomas Euler, Thomas Roggenkamp, Julian Zemke. Obstacle marks as palaeohydraulic indicators of Pleistocene megafloods. Water Policy. 2012; 44 (2):300-317.
Chicago/Turabian StyleJürgen Herget; Thomas Euler; Thomas Roggenkamp; Julian Zemke. 2012. "Obstacle marks as palaeohydraulic indicators of Pleistocene megafloods." Water Policy 44, no. 2: 300-317.