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Conventional dredging of ditches and streams to ensure agricultural drainage and flood mitigation can have severe environmental impacts. The aim of this paper is to investigate the potential benefits of an alternative, nature-based two-stage channel (TSC) design with floodplains excavated along the main channel. Through a literature survey, investigations at Finnish field sites and expert interviews, we assessed the performance, costs, and monetary environmental benefits of TSCs in comparison to conventional dredging, as well as the bottlenecks in their financing and governance. We found evidence supporting the expected longer-term functioning of drainage as well as larger plant and fish biodiversity in TSCs compared to conventional dredging. The TSC design likely improves water quality since the floodplains retain suspended sediment and phosphorus and remove nitrogen. In the investigated case, the additional value of phosphorus retention and conservation of protected species through the TSC design was 2.4 times higher than the total costs. We demonstrate how TSCs can be made eligible for the obligatory vegetated riparian buffer of the European Union agri-environmental subsidy scheme (CAP-AES) by optimising their spatial application with respect to other buffer measures, and recommend to publicly finance their additional costs compared to conventional dredging at priority sites. Further studies on biodiversity impacts and long-term performance of two-stage channels are required.
Kaisa Västilä; Sari Väisänen; Jari Koskiaho; Virpi Lehtoranta; Krister Karttunen; Mikko Kuussaari; Juha Järvelä; Kauko Koikkalainen. Agricultural Water Management Using Two-Stage Channels: Performance and Policy Recommendations Based on Northern European Experiences. Sustainability 2021, 13, 9349 .
AMA StyleKaisa Västilä, Sari Väisänen, Jari Koskiaho, Virpi Lehtoranta, Krister Karttunen, Mikko Kuussaari, Juha Järvelä, Kauko Koikkalainen. Agricultural Water Management Using Two-Stage Channels: Performance and Policy Recommendations Based on Northern European Experiences. Sustainability. 2021; 13 (16):9349.
Chicago/Turabian StyleKaisa Västilä; Sari Väisänen; Jari Koskiaho; Virpi Lehtoranta; Krister Karttunen; Mikko Kuussaari; Juha Järvelä; Kauko Koikkalainen. 2021. "Agricultural Water Management Using Two-Stage Channels: Performance and Policy Recommendations Based on Northern European Experiences." Sustainability 13, no. 16: 9349.
Natural riparian vegetation generally presents a complex hydrodynamic behavior governed by plant morphology and flexibility. By contrast, hydrodynamic processes in partly vegetated channels are conventionally simulated by using simplified model vegetation, such as arrays of rigid cylinders. The aim of this study is to investigate the impacts of embedding natural plant features in the experimental simulation of flow in partly vegetated channels. Unique comparative experiments were carried out with both reconfiguring vegetation made of natural‐like shrubs and grasses, and with rigid cylinders. While the lateral distributions of flow properties presented a high similarity governed by the shear layer differential velocity ratio, the bulk vegetative drag, and the presence of large‐scale vortices, the flexibility‐induced mechanisms of natural‐like vegetation markedly affected the flow at the interface. Differences in plant morphology and spacing, and the dynamic motion of flexible foliated plants induced deeper vortex penetration into the vegetation. The normalized shear penetration was 6‐10 times greater than observed for rigid cylinders, resulting in wider zones significantly exchanging momentum with the adjacent open water. The efficiency of lateral momentum transport for flexible foliated vegetation was up to 40% greater than the corresponding rigid cylinder case. Overall, the results indicated that improving the representativeness of model vegetation is a critical step toward the accurate simulation of hydrodynamic and transport processes in natural settings.This article is protected by copyright. All rights reserved.
Gerardo Caroppi; Kaisa Västilä; Paola Gualtieri; Juha Järvelä; Maurizio Giugni; Paweł M. Rowiński. Comparison of Flexible and Rigid Vegetation Induced Shear Layers in Partly Vegetated Channels. Water Resources Research 2021, 57, 1 .
AMA StyleGerardo Caroppi, Kaisa Västilä, Paola Gualtieri, Juha Järvelä, Maurizio Giugni, Paweł M. Rowiński. Comparison of Flexible and Rigid Vegetation Induced Shear Layers in Partly Vegetated Channels. Water Resources Research. 2021; 57 (3):1.
Chicago/Turabian StyleGerardo Caroppi; Kaisa Västilä; Paola Gualtieri; Juha Järvelä; Maurizio Giugni; Paweł M. Rowiński. 2021. "Comparison of Flexible and Rigid Vegetation Induced Shear Layers in Partly Vegetated Channels." Water Resources Research 57, no. 3: 1.
This paper investigates the interplay between the flow, suspended sediment concentration (SSC), and net deposition at the lateral interface between a main channel and riverbank/floodplain vegetation consisting of emergent flexible woody plants with understory grasses. In a new set of flume experiments, data were collected concurrently on the flow field, SSC, and net deposition using acoustic Doppler velocimeters, optical turbidity sensors, and weight-based sampling. Vegetation largely affected the vertical SSC distributions, both within and near the vegetated areas. The seasonal variation of vegetation properties was important, as the foliage strongly increased lateral mixing of suspended sediments between the unvegetated and vegetated parts of the channel. Foliage increased the reach-scale net deposition and enhanced deposition in the understory grasses at the main channel–vegetation interface. To estimate the seasonal differences caused by foliation, we introduced a new drag ratio approach for describing the SSC difference between the vegetated and unvegetated channel parts. Findings in this study suggest that future research and engineering applications will benefit from a more realistic description of natural plant features, including the reconfiguration of plants and drag by the foliage, to complement and replace existing rigid cylinder approaches.
Walter Box; Kaisa Västilä; Juha Järvelä. The Interplay between Flow Field, Suspended Sediment Concentration, and Net Deposition in a Channel with Flexible Bank Vegetation. Water 2019, 11, 2250 .
AMA StyleWalter Box, Kaisa Västilä, Juha Järvelä. The Interplay between Flow Field, Suspended Sediment Concentration, and Net Deposition in a Channel with Flexible Bank Vegetation. Water. 2019; 11 (11):2250.
Chicago/Turabian StyleWalter Box; Kaisa Västilä; Juha Järvelä. 2019. "The Interplay between Flow Field, Suspended Sediment Concentration, and Net Deposition in a Channel with Flexible Bank Vegetation." Water 11, no. 11: 2250.
Riparian shrubs and trees present a complex, seasonally variable morphology, with flexible stems and leaves efficiently adapting to the flow forcing (reconfiguration). The aim of this paper is to investigate how foliage and reconfiguration affect the flow and mixing in a partly vegetated channel. Specific attention was placed on the velocity statistics, onset and coherence of turbulent structures, and lateral momentum transport at the horizontal interface between vegetation and open water. The experimental flume arrangement was novel in that it allowed investigating the lateral shear layer induced by flexible riparian plants. The natural-like vegetation consisted of emergent woody plants and a grassy understory, with density, morphology and reconfiguration behavior comparable to those found in real riparian areas. Investigations were conducted under foliated and leafless conditions to determine the seasonality effects. The mean and turbulent flow structure was determined with acoustic Doppler velocimetry, and dynamic plant motions were investigated from video footage. The presence of foliage enhanced the drag discontinuity at the interface, resulting in more pronounced velocity gradients between the vegetated and open areas compared to the leafless conditions. Foliation induced stronger shear layer-scale mixing, whereas, under leafless conditions, the local mixing induced by stems was more important. The reconfiguration decreased the coherence of the two-dimensional large-scale vortices at the interface while their characteristic frequency was consistent with the canonical mixing layer theory. Our results indicated that shear layer dynamics in partly vegetated channels was influenced strongly by morphology and reconfiguration of complex plants, with more efficient lateral momentum transport at the interface in the foliated conditions than previously reported for shear layers induced by simpler vegetation.
Gerardo Caroppi; Kaisa Västilä; Juha Järvelä; Paweł M. Rowiński; Maurizio Giugni. Turbulence at water-vegetation interface in open channel flow: Experiments with natural-like plants. Advances in Water Resources 2019, 127, 180 -191.
AMA StyleGerardo Caroppi, Kaisa Västilä, Juha Järvelä, Paweł M. Rowiński, Maurizio Giugni. Turbulence at water-vegetation interface in open channel flow: Experiments with natural-like plants. Advances in Water Resources. 2019; 127 ():180-191.
Chicago/Turabian StyleGerardo Caroppi; Kaisa Västilä; Juha Järvelä; Paweł M. Rowiński; Maurizio Giugni. 2019. "Turbulence at water-vegetation interface in open channel flow: Experiments with natural-like plants." Advances in Water Resources 127, no. : 180-191.
Riparian plants exert flow resistance and largely influence the flow structure, which affects erosion, deposition and transport processes of fine sediments. Predicting these vegetative effects is important for flood, sediment and nutrient management. However, predictions on the fate of sediments are complicated by uncertainties associated with the suitable parameterization of natural plants and the associated effects on the turbulent flow field and on the variables in the transport equations. The aim of this study is to quantify deposition and transport of fine sandy sediment in a partly vegetated channel under laboratory conditions. Care was taken to reproduce conditions typical of vegetated floodplain flows including dense flexible grassy understory as a starting point. The experiments were conducted in a flume that is specifically designed to recirculate fine sediment. We measured suspended sediment concentrations with optical turbidity sensors and determined patterns of net deposition over the vegetated parts of the cross section. The flow field was determined with acoustic Doppler velocimetry. Our investigations are intended to improve future predictions of fine sediment storage and transport in natural or constructed vegetated channels, and the first results reported herein were useful in designing further, on-going experiments with complex combinations of vegetation and channel geometry. Key words: sediment transport, suspended sediment, deposition, riparian vegetation, flow field.
Walter Box; Kaisa Västilä; Juha Järvelä. Transport and deposition of fine sediment in a channel partly covered by flexible vegetation. E3S Web of Conferences 2018, 40, 02016 .
AMA StyleWalter Box, Kaisa Västilä, Juha Järvelä. Transport and deposition of fine sediment in a channel partly covered by flexible vegetation. E3S Web of Conferences. 2018; 40 ():02016.
Chicago/Turabian StyleWalter Box; Kaisa Västilä; Juha Järvelä. 2018. "Transport and deposition of fine sediment in a channel partly covered by flexible vegetation." E3S Web of Conferences 40, no. : 02016.
New sustainable, cost-effective solutions are urgently needed for river management since conventional practices have posed serious ecological threats on streams, rivers and the surrounding riparian areas. Besides addressing the societal needs e.g. for flood management, river management should increasingly address the ecosystem requirements for improved water quality and biodiversity. We argue that it is not feasible to solve existing and future river management challenges with intensive restoration projects. Instead, we believe that less resource-intensive solutions using natural channel processes and features, including vegetation, should be investigated. Besides directly supporting biota, aquatic and riparian vegetation traps, takes up and helps to process nutrients and harmful substances, and thus this paper emphasizes vegetation as a tool for nature-based solutions (NBS) in river management. In this paper, emphasis is placed on the usage of vegetation as a NBS in river management. We synthesize findings from key literature, showing that the fate of substances in channel systems is largely controlled by abiotic and biotic processes facilitated and modified by vegetation, including flow hydrodynamics, channel morphology, and sediment transport. Subsequently, we demonstrate how vegetation can be incorporated into channel designs, focusing on a two-stage (compound) design to improve resilience to flooding, control the transport of substances, and enhance the ecological status. As a conclusion, clever use and maintenance of vegetation present unused potential to obtain large-scale positive environmental impacts in rivers and streams experiencing anthropogenic pressures.
Paweł M. Rowiński; Kaisa Västilä; Jochen Aberle; Juha Järvelä; Monika B. Kalinowska. How vegetation can aid in coping with river management challenges: A brief review. Ecohydrology & Hydrobiology 2018, 18, 345 -354.
AMA StylePaweł M. Rowiński, Kaisa Västilä, Jochen Aberle, Juha Järvelä, Monika B. Kalinowska. How vegetation can aid in coping with river management challenges: A brief review. Ecohydrology & Hydrobiology. 2018; 18 (4):345-354.
Chicago/Turabian StylePaweł M. Rowiński; Kaisa Västilä; Jochen Aberle; Juha Järvelä; Monika B. Kalinowska. 2018. "How vegetation can aid in coping with river management challenges: A brief review." Ecohydrology & Hydrobiology 18, no. 4: 345-354.
Kaisa Västilä; Juha Järvelä. Correction to: Characterizing natural riparian vegetation for modeling of flow and suspended sediment transport. Journal of Soils and Sediments 2017, 18, 3131 -3132.
AMA StyleKaisa Västilä, Juha Järvelä. Correction to: Characterizing natural riparian vegetation for modeling of flow and suspended sediment transport. Journal of Soils and Sediments. 2017; 18 (10):3131-3132.
Chicago/Turabian StyleKaisa Västilä; Juha Järvelä. 2017. "Correction to: Characterizing natural riparian vegetation for modeling of flow and suspended sediment transport." Journal of Soils and Sediments 18, no. 10: 3131-3132.
Riparian vegetation imposes a critical control on the transport and deposition of suspended sediment with important implications for water quality and channel maintenance. This paper contributes (1) to hydraulic and morphological modeling by examining the parameterization of natural riparian vegetation (trees, bushes, and grasses) and (2) to the design and management of environmental channels by determining how the properties of natural floodplain plant stands affect the erosion and deposition of suspended sediment. Laboratory and field data were employed for enhancing the physical description of flow–plant–sediment interactions with a consideration of practical applicability. A drag force parameterization that takes into account the flexibility-induced reconfiguration, and the complex structure of foliated plants was validated for small natural trees under laboratory conditions, while the data from a small vegetated compound channel demonstrated the approaches at the field scale. Based on the field data, we identified three key vegetative factors influencing the net deposition and erosion on the floodplain. The significance of these factors was evaluated for vegetative conditions ranging from almost bare soil to sparse willows and dense grasses. Overall, the investigated conditions covered flexible and rigid vegetation with seasonal differences represented by foliated and leafless states. The drag and reconfiguration of woody plants were reliably predicted under leafless and foliated conditions. Subsequently, we present a new easy-to-use methodology for predicting vegetative drag and flow resistance. The methodology is based on a physically solid parameterization for five widely used coefficients or terms (Eqs. (2)–(6)), with the necessary parameter values presented for common riparian species. The methodology was coupled with existing approaches at the field scale, revealing that increasing vegetation density and the associated decreasing flow velocity within vegetation significantly increased net deposition. Further, deposition increased with increasing cross-sectional vegetative blockage and decreasing distance from the suspended sediment replenishment point. Thus, longitudinal advection was the most important mechanism supplying fine sediment to the floodplain, but long continuous plant stands limited deposition. The proposed parameterization (Eqs. (2)–(6)) can be readily implemented into existing hydraulic and morphological models to improve the description of natural vegetation compared to the conventional rigid cylinder representation. The approach is advantageous for evaluating, for example, the effects of both natural succession and management interventions on floodplains. Finally, guidance is provided on how floodplain vegetation can be maintained to manage the erosion and deposition of suspended sediment in environmental channel designs.
Kaisa Västilä; Juha Järvelä. Characterizing natural riparian vegetation for modeling of flow and suspended sediment transport. Journal of Soils and Sediments 2017, 18, 3114 -3130.
AMA StyleKaisa Västilä, Juha Järvelä. Characterizing natural riparian vegetation for modeling of flow and suspended sediment transport. Journal of Soils and Sediments. 2017; 18 (10):3114-3130.
Chicago/Turabian StyleKaisa Västilä; Juha Järvelä. 2017. "Characterizing natural riparian vegetation for modeling of flow and suspended sediment transport." Journal of Soils and Sediments 18, no. 10: 3114-3130.
Riparian vegetation imposes a critical control on transport and deposition of suspended sediment with important implications on water quality as well as channel maintenance. With a view on hydraulic and morphological modeling needs, the objective of this paper is to enhance the parameterization of foliated riparian vegetation and to determine how the properties of plant stands affect the erosion and deposition of suspended sediment on a naturally vegetated floodplain. We show that the drag forces of woody plants can be reliably predicted with a parameterization that takes into account their flexibility-induced reconfiguration and complex structure. Based on field investigations in a vegetated compound channel, a multiple regression model was constructed to explain the net deposition and erosion under vegetative conditions ranging from almost bare soil to sparse willows and dense grasses. Net deposition was positively correlated with the cross-sectional vegetative blockage factor and negatively correlated with the distance from the suspended sediment replenishment point, indicating that longitudinal advection was the most important mechanism supplying fine sediment to the floodplain plant stands under real field conditions. Deposition increased with decreasing flow velocity within the natural stands. As an implication to hydraulic and morphological modeling, the proposed drag force parameterization can be easily implemented into model codes to improve the description of flexible, foliated vegetation. The paper concludes by providing guidance on how floodplain vegetation can be maintained to manage the erosion and deposition of suspended sediment.
Kaisa Västilä; Juha Järvelä. Characterizing natural riparian plant stands for modeling of flow and suspended sediment transport. River Sedimentation 2016, 943 -952.
AMA StyleKaisa Västilä, Juha Järvelä. Characterizing natural riparian plant stands for modeling of flow and suspended sediment transport. River Sedimentation. 2016; ():943-952.
Chicago/Turabian StyleKaisa Västilä; Juha Järvelä. 2016. "Characterizing natural riparian plant stands for modeling of flow and suspended sediment transport." River Sedimentation , no. : 943-952.
Clemens Weissteiner; Johanna Jalonen; Juha Järvelä; Hans Peter Rauch. Corrigendum to: “Spatial–structural properties of woody riparian vegetation with a view on reconfiguration under hydrodynamic loading” [Ecol. Eng. 85 (2015) 85–94]. Ecological Engineering 2016, 94, 698 .
AMA StyleClemens Weissteiner, Johanna Jalonen, Juha Järvelä, Hans Peter Rauch. Corrigendum to: “Spatial–structural properties of woody riparian vegetation with a view on reconfiguration under hydrodynamic loading” [Ecol. Eng. 85 (2015) 85–94]. Ecological Engineering. 2016; 94 ():698.
Chicago/Turabian StyleClemens Weissteiner; Johanna Jalonen; Juha Järvelä; Hans Peter Rauch. 2016. "Corrigendum to: “Spatial–structural properties of woody riparian vegetation with a view on reconfiguration under hydrodynamic loading” [Ecol. Eng. 85 (2015) 85–94]." Ecological Engineering 94, no. : 698.
J Järvelä; J Aberle; J Jalonen. Dynamic reconfiguration of riparian trees in towing tank experiments. River Flow 2016 2016, 1 .
AMA StyleJ Järvelä, J Aberle, J Jalonen. Dynamic reconfiguration of riparian trees in towing tank experiments. River Flow 2016. 2016; ():1.
Chicago/Turabian StyleJ Järvelä; J Aberle; J Jalonen. 2016. "Dynamic reconfiguration of riparian trees in towing tank experiments." River Flow 2016 , no. : 1.
The purpose of this study was to quantify how vegetation influences the flow and sediment processes relevant to the design and management of environmental compound channels. Therefore, a two-year field investigation was conducted in a cohesive two-stage channel, focusing on the flow resistance and net deposition in five subreaches with different floodplain vegetation conditions. In the grassy subreaches, the cross-sectional blockage factor was the key vegetation property governing the flow resistance, with a process-based model providing reliable estimates under widely variable hydraulic and vegetative conditions. The net deposition of cohesive sediment was best explained by vegetation height while high stand length and density created supply-limited conditions on the inner floodplain. These results showed that the two-stage approach offers potential for controlling the sediment processes through appropriate vegetation maintenance. The novelty of this research is that straightforward analyses accompanied by a physically-based parameterization of the floodplain plant stands were successfully used to characterize the flow–vegetation–sediment interaction in a practical engineering application. The results are expected to be helpful in designing and managing comparable channels.
K. Västilä; Juha Järvelä; Harri Koivusalo. Flow–Vegetation–Sediment Interaction in a Cohesive Compound Channel. Journal of Hydraulic Engineering 2016, 142, 04015034 .
AMA StyleK. Västilä, Juha Järvelä, Harri Koivusalo. Flow–Vegetation–Sediment Interaction in a Cohesive Compound Channel. Journal of Hydraulic Engineering. 2016; 142 (1):04015034.
Chicago/Turabian StyleK. Västilä; Juha Järvelä; Harri Koivusalo. 2016. "Flow–Vegetation–Sediment Interaction in a Cohesive Compound Channel." Journal of Hydraulic Engineering 142, no. 1: 04015034.
This paper investigates the structural properties of four common riparian tree species and their reconfiguration under hydrodynamic loading in a towing tank in foliated and defoliated conditions. 3D tree models were generated by digitizing twenty 0.8–3.3 m tall specimens at branch level. Branch diameters and lengths were measured in order to calculate the one-sided stem area and stem volume over the plant height. The novelty of the investigations originated from the characterization of the reconfiguration which was achieved by combining the contracted width, the deflected height, and the underwater projected area in order to determine the porosity at different velocities. The results showed that the basal diameter could be used to predict the entire total one-sided stem area, although this method was not capable of reproducing the observed non-linear vertical distributions. The flow-induced width contraction contributed significantly to the reduction of the rectangular cross-sectional area occupied by the plant. The porosity of the foliated trees increased at the lower velocities, and then decreased at the higher velocities. Overall, detailed spatial–structural analyses of woody vegetation provided valuable information about plant behaviour under load, and thus are helpful for improving the determination of the physically based parameters of complex vegetative elements which is highly relevant for environmental modelling in order to fill the gap of knowledge concerning the hydrodynamic and aerodynamic flow around trees.
Clemens Weissteiner; Johanna Jalonen; Juha Järvelä; Hans Peter Rauch. Spatial–structural properties of woody riparian vegetation with a view to reconfiguration under hydrodynamic loading. Ecological Engineering 2015, 85, 85 -94.
AMA StyleClemens Weissteiner, Johanna Jalonen, Juha Järvelä, Hans Peter Rauch. Spatial–structural properties of woody riparian vegetation with a view to reconfiguration under hydrodynamic loading. Ecological Engineering. 2015; 85 ():85-94.
Chicago/Turabian StyleClemens Weissteiner; Johanna Jalonen; Juha Järvelä; Hans Peter Rauch. 2015. "Spatial–structural properties of woody riparian vegetation with a view to reconfiguration under hydrodynamic loading." Ecological Engineering 85, no. : 85-94.
Hydrodynamics of vegetated channels and streams is a rapidly developing research area, and this chapter summarizes the current knowledge considering both aquatic and riparian zones. The benefit of an advanced parameterization of plant morphology and biomechanical properties is highlighted. For this purpose, the response of flexible and foliated plants and plant communities to the flow is illustrated, and advanced models for the determination of drag forces of flexible plants are described. Hydrodynamic processes governing flow patterns in vegetated flows are presented for submerged and emergent conditions considering spatial scales ranging from the leaf to the vegetated reach scale.
Jochen Aberle; Juha Järvelä. Hydrodynamics of Vegetated Channels. Flood Risk in the Upper Vistula Basin 2015, 519 -541.
AMA StyleJochen Aberle, Juha Järvelä. Hydrodynamics of Vegetated Channels. Flood Risk in the Upper Vistula Basin. 2015; ():519-541.
Chicago/Turabian StyleJochen Aberle; Juha Järvelä. 2015. "Hydrodynamics of Vegetated Channels." Flood Risk in the Upper Vistula Basin , no. : 519-541.
Johanna Jalonen; Juha Järvelä. Erratum to “Estimation of drag forces caused by natural woody vegetation of different scales”. Journal of Hydrodynamics 2015, 27, 319 -319.
AMA StyleJohanna Jalonen, Juha Järvelä. Erratum to “Estimation of drag forces caused by natural woody vegetation of different scales”. Journal of Hydrodynamics. 2015; 27 (2):319-319.
Chicago/Turabian StyleJohanna Jalonen; Juha Järvelä. 2015. "Erratum to “Estimation of drag forces caused by natural woody vegetation of different scales”." Journal of Hydrodynamics 27, no. 2: 319-319.
Detailed modeling of floodplain flows and associated processes requires data on mixed, heterogeneous vegetation at river reach scale, though the collection of vegetation data is typically limited in resolution or lack spatial information. This study investigates physically-based characterization of mixed floodplain vegetation by means of terrestrial laser scanning (TLS). The work aimed at developing an approach for deriving the characteristic reference areas of herbaceous and foliated woody vegetation, and estimating the vertical distribution of woody vegetation. Detailed experimental data on vegetation properties were gathered both in a floodplain site for herbaceous vegetation, and under laboratory conditions for 2–3 m tall trees. The total plant area (Atot) of woody vegetation correlated linearly with the TLS-based voxel count, whereas the Atot of herbaceous vegetation showed a linear correlation with TLS-based vegetation mean height. For woody vegetation, 1 cm voxel size was found suitable for estimating both the Atot and its vertical distribution. A new concept was proposed for deriving Atot for larger areas from the point cloud attributes of small sub-areas. The results indicated that the relationships between the TLS attributes and Atot of the sub-areas can be derived either by mm resolution TLS or by manual vegetation sampling.
Johanna Jalonen; Juha Järvelä; Juho-Pekka Virtanen; Matti Vaaja; Matti Kurkela; Hannu Hyyppä. Determining Characteristic Vegetation Areas by Terrestrial Laser Scanning for Floodplain Flow Modeling. Water 2015, 7, 420 -437.
AMA StyleJohanna Jalonen, Juha Järvelä, Juho-Pekka Virtanen, Matti Vaaja, Matti Kurkela, Hannu Hyyppä. Determining Characteristic Vegetation Areas by Terrestrial Laser Scanning for Floodplain Flow Modeling. Water. 2015; 7 (12):420-437.
Chicago/Turabian StyleJohanna Jalonen; Juha Järvelä; Juho-Pekka Virtanen; Matti Vaaja; Matti Kurkela; Hannu Hyyppä. 2015. "Determining Characteristic Vegetation Areas by Terrestrial Laser Scanning for Floodplain Flow Modeling." Water 7, no. 12: 420-437.
J. Jalonen; Juha Järvelä; H. Koivusalo; H. Hyyppä. Deriving Floodplain Topography and Vegetation Characteristics for Hydraulic Engineering Applications by Means of Terrestrial Laser Scanning. Journal of Hydraulic Engineering 2014, 140, 04014056 .
AMA StyleJ. Jalonen, Juha Järvelä, H. Koivusalo, H. Hyyppä. Deriving Floodplain Topography and Vegetation Characteristics for Hydraulic Engineering Applications by Means of Terrestrial Laser Scanning. Journal of Hydraulic Engineering. 2014; 140 (11):04014056.
Chicago/Turabian StyleJ. Jalonen; Juha Järvelä; H. Koivusalo; H. Hyyppä. 2014. "Deriving Floodplain Topography and Vegetation Characteristics for Hydraulic Engineering Applications by Means of Terrestrial Laser Scanning." Journal of Hydraulic Engineering 140, no. 11: 04014056.
Johanna Jalonen; Juha Järvelä. Estimation of drag forces caused by natural woody vegetation of different scales. Journal of Hydrodynamics 2014, 26, 608 -623.
AMA StyleJohanna Jalonen, Juha Järvelä. Estimation of drag forces caused by natural woody vegetation of different scales. Journal of Hydrodynamics. 2014; 26 (4):608-623.
Chicago/Turabian StyleJohanna Jalonen; Juha Järvelä. 2014. "Estimation of drag forces caused by natural woody vegetation of different scales." Journal of Hydrodynamics 26, no. 4: 608-623.
[1] Both the foliage and stem essentially influence the flow resistance of woody plants, but their different biomechanical properties complicate the parameterization of foliated vegetation for modeling. This paper investigates whether modeling of flow resistance caused by natural woody vegetation can be improved using explicit description of both the foliage and stem. For this purpose, we directly measured the drag forces of Alnus glutinosa, Betula pendula, Salix viminalis, and Salix x rubens twigs in a laboratory flume at four foliation levels, parameterized with the leaf‐area‐to‐stem‐area ratio AL/AS. The species differed in the foliage drag but had approximately equal stem drag. For the foliated twigs, increasing AL/AS was found to increase the reconfiguration and the share of the foliage drag to the total drag. The experiments provided new insight into the factors governing the flow resistance of natural woody vegetation and allowed us to develop a model for estimating the vegetative friction factor using the linear superposition of the foliage and stem drag. The model is novel in that the foliage and stem are separately described with physically based parameters: drag coefficients, reconfiguration parameters, and leaf area and frontal‐projected stem area per ground area. The model could satisfactorily predict the flow resistance of twig to sapling‐sized specimens of the investigated species at velocities of 0.05–1 m/s. As a further benefit, the model allows exploring the variability in drag and reconfiguration associated with differing abundance of the foliage in relation to the stem.
Kaisa Västilä; Juha Järvelä. Modeling the flow resistance of woody vegetation using physically based properties of the foliage and stem. Water Resources Research 2014, 50, 229 -245.
AMA StyleKaisa Västilä, Juha Järvelä. Modeling the flow resistance of woody vegetation using physically based properties of the foliage and stem. Water Resources Research. 2014; 50 (1):229-245.
Chicago/Turabian StyleKaisa Västilä; Juha Järvelä. 2014. "Modeling the flow resistance of woody vegetation using physically based properties of the foliage and stem." Water Resources Research 50, no. 1: 229-245.
Mobile mapping systems (MMSs) are used for mapping topographic and urban features which are difficult and time consuming to measure with other instruments. The benefits of MMSs include efficient data collection and versatile usability. This paper investigates the data processing steps and quality of a boat-based mobile mapping system (BoMMS) data for generating terrain and vegetation points in a river environment. Our aim in data processing was to filter noise points, detect shorelines as well as points below water surface and conduct ground point classification. Previous studies of BoMMS have investigated elevation accuracies and usability in detection of fluvial erosion and deposition areas. The new findings concerning BoMMS data are that the improved data processing approach allows for identification of multipath reflections and shoreline delineation. We demonstrate the possibility to measure bathymetry data in shallow (0–1 m) and clear water. Furthermore, we evaluate for the first time the accuracy of the BoMMS ground points classification compared to manually classified data. We also demonstrate the spatial variations of the ground point density and assess elevation and vertical accuracies of the BoMMS data.
Matti Vaaja; Antero Kukko; Harri Kaartinen; Matti Kurkela; Elina Kasvi; Claude Flener; Hannu Hyyppä; Juha Hyyppä; Juha Järvelä; Petteri Alho. Data Processing and Quality Evaluation of a Boat-Based Mobile Laser Scanning System. Sensors 2013, 13, 12497 -12515.
AMA StyleMatti Vaaja, Antero Kukko, Harri Kaartinen, Matti Kurkela, Elina Kasvi, Claude Flener, Hannu Hyyppä, Juha Hyyppä, Juha Järvelä, Petteri Alho. Data Processing and Quality Evaluation of a Boat-Based Mobile Laser Scanning System. Sensors. 2013; 13 (9):12497-12515.
Chicago/Turabian StyleMatti Vaaja; Antero Kukko; Harri Kaartinen; Matti Kurkela; Elina Kasvi; Claude Flener; Hannu Hyyppä; Juha Hyyppä; Juha Järvelä; Petteri Alho. 2013. "Data Processing and Quality Evaluation of a Boat-Based Mobile Laser Scanning System." Sensors 13, no. 9: 12497-12515.