scholarly journals Improvements to stream extraction and soil wetness mapping within a forested catchment by increasing airborne LiDAR data density – a case study in Parkano, western Finland

Silva Fennica ◽  
2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Mikko Niemi
Keyword(s):  
Overland Flow ◽  
Interpolation Method ◽  
Airborne Lidar ◽  
Lidar Data ◽  
Topographic Wetness Index ◽  
Flow Routing ◽  
Pulse Density ◽  
Data Density ◽  
Soil Wetness ◽  
Overland Flow Routing

The pulse density of airborne Light Detection and Ranging (LiDAR) is increasing due to technical developments. The trade-offs between pulse density, inventory costs, and forest attribute measurement accuracy are extensively studied, but the possibilities of high-density airborne LiDAR in stream extraction and soil wetness mapping are unknown. This study aimed to refine the best practices for generating a hydrologically conditioned digital elevation model (DEM) from an airborne LiDAR -derived 3D point cloud. Depressionless DEMs were processed using a stepwise breaching-filling method, and the performance of overland flow routing was studied in relation to a pulse density, an interpolation method, and a raster cell size. The study area was situated on a densely ditched forestry site in Parkano municipality, for which LiDAR data with a pulse density of 5 m were available. Stream networks and a topographic wetness index (TWI) were derived from altogether 12 DEM versions. The topological database of Finland was used as a ground reference in comparison, in addition to 40 selected main flow routes within the catchment. The results show improved performance of overland flow modeling due to increased data density. In addition, commonly used triangulated irregular networks were clearly outperformed by universal kriging and inverse-distance weighting in DEM interpolation. However, the TWI proved to be more sensitive to pulse density than an interpolation method. Improved overland flow routing contributes to enhanced forest resource planning at detailed spatial scales.–2

Coupled infiltration and surface tunoff on a 5 Ha experimental catchment, Krawarree, N.S.W

Soil Research ◽  
1979 ◽  
Vol 17 (1) ◽  
pp. 53 ◽  
Author(s):  
AR Aston ◽  
FX Dunin
Keyword(s):  
Overland Flow ◽  
Two Stage ◽  
Flow Routing ◽  
Constant Intensity ◽  
Rainfall Events ◽  
Infiltration Model ◽  
Overland Flow Routing ◽  
Good Agreement

A simple two-stage infiltration model, originally developed for infiltration under constant intensity rainfall, was adapted to varying rainfall inputs and coupled with an overland flow routing procedure. The model was verified against selected rainfall events on a 5 ha experimental catchment with good agreement between simulated and measured catchment yields.

An efficient method for DEM-based overland flow routing

2013 ◽  
Vol 489 ◽  
pp. 238-245 ◽  
Author(s):  
Pin-Chun Huang ◽  
Kwan Tun Lee
Keyword(s):  
Efficient Method ◽  
Overland Flow ◽  
Flow Routing ◽  
Overland Flow Routing

scholarly journals A new method, with application, for analysis of the impacts on flood risk of widely distributed enhanced hillslope storage

2018 ◽  
Vol 22 (4) ◽  
pp. 2589-2605 ◽  
Author(s):  
Peter Metcalfe ◽  
Keith Beven ◽  
Barry Hankin ◽  
Rob Lamb
Keyword(s):  
Flood Risk ◽  
Overland Flow ◽  
Uncertainty Estimation ◽  
Surface Flow ◽  
Flow Routing ◽  
Sequence Of Events ◽  
Run Off ◽  
Extreme Flood ◽  
Overland Flow Routing ◽  
Flood Waves

Abstract. Enhanced hillslope storage is utilised in “natural” flood management in order to retain overland storm run-off and to reduce connectivity between fast surface flow pathways and the channel. Examples include excavated ponds, deepened or bunded accumulation areas, and gullies and ephemeral channels blocked with wooden barriers or debris dams. The performance of large, distributed networks of such measures is poorly understood. Extensive schemes can potentially retain large quantities of run-off, but there are indications that much of their effectiveness can be attributed to desynchronisation of sub-catchment flood waves. Inappropriately sited measures may therefore increase, rather than mitigate, flood risk. Fully distributed hydrodynamic models have been applied in limited studies but introduce significant computational complexity. The longer run times of such models also restrict their use for uncertainty estimation or evaluation of the many potential configurations and storm sequences that may influence the timings and magnitudes of flood waves. Here a simplified overland flow-routing module and semi-distributed representation of enhanced hillslope storage is developed. It is applied to the headwaters of a large rural catchment in Cumbria, UK, where the use of an extensive network of storage features is proposed as a flood mitigation strategy. The models were run within a Monte Carlo framework against data for a 2-month period of extreme flood events that caused significant damage in areas downstream. Acceptable realisations and likelihood weightings were identified using the GLUE uncertainty estimation framework. Behavioural realisations were rerun against the catchment model modified with the addition of the hillslope storage. Three different drainage rate parameters were applied across the network of hillslope storage. The study demonstrates that schemes comprising widely distributed hillslope storage can be modelled effectively within such a reduced complexity framework. It shows the importance of drainage rates from storage features while operating through a sequence of events. We discuss limitations in the simplified representation of overland flow-routing and representation and storage, and how this could be improved using experimental evidence. We suggest ways in which features could be grouped more strategically and thus improve the performance of such schemes.

scholarly journals A Topographic Wetness Index for Forest Road Quality Assessment: An Application in the Lakeland Region of Finland

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1165
Author(s):  
Katalin Waga ◽  
Jukka Malinen ◽  
Timo Tokola
Keyword(s):  
Boreal Forests ◽  
Road Network ◽  
Airborne Lidar ◽  
Lidar Data ◽  
Topographic Wetness Index ◽  
Forest Roads ◽  
Wetness Index ◽  
Forest Road ◽  
Airborne Lidar Data ◽  
Quality Assessments

Research Highlights: A Topographic Wetness Index calculated using LiDAR-derived elevation models can help in identifying unpaved forest roads that need maintenance. Materials and Methods: Low-pulse LiDAR data were used to calculate a Topographic Wetness Index to predict unpaved forest roads’ quality. Results: The results of this analysis and comparison of road-quality features derived from LiDAR data at resolutions of 1, 10 and 25 m for assessing road quality in the boreal forests of Finnish Lakeland show that the wetness index can predict road quality correctly in up to 70% of cases and up to 86% when combined with other auxiliary GIS-based variables. Conclusions: Road-quality assessments, using airborne LiDAR data, can greatly help forest managers to decide which sections of the ageing road network will benefit the most from maintenance, while reducing the need of field visits.

scholarly journals Simplified representation of runoff attenuation features within analysis of the hydrological performance of a natural flood management scheme

2017 ◽  
Author(s):  
Peter Metcalfe ◽  
Keith Beven ◽  
Barry Hankin ◽  
Rob Lamb
Keyword(s):  
Overland Flow ◽  
Flood Management ◽  
Uncertainty Estimation ◽  
Flow Routing ◽  
Antecedent Conditions ◽  
Sequence Of Events ◽  
Extreme Flood ◽  
Flow Pathways ◽  
Overland Flow Routing ◽  
Flood Waves

Abstract. Hillslope Runoff Attenuation Features (RAFs) are soft-engineered overland flow interception structures utilised in natural flood management, designed to reduce connectivity between fast overland flow pathways and the channel. The performance of distributed networks of these features is poorly understood. Extensive schemes can potentially retain large quantities of runoff storage but there are suggestions that much of their effectiveness can be attributed to desynchronisation of subcatchment flood waves, and that inappropriately-sited measures may increase rather than mitigate flood risk. Fully-distributed hydrodynamic models have been applied in limited studies but introduce computational complexity. The longer run-times of such models also restricts their use for uncertainty estimation or evaluation of the many potential configurations and storm sequences that may influence the timing and magnitude of flood waves. We applied a simplified overland flow routing module and representation of RAFs to the headwaters of a large rural catchment in Cumbria, U.K., where the use of an extensive network of such features is proposed as a flood mitigation strategy. The model was run in a Monte Carlo framework over a two-month period of extreme flood events which occurred in late 2015 that caused significant damage in areas downstream. Using the GLUE uncertainty estimation framework, we scored our set of acceptable realisations and these weighted behavioural realisations were rerun with one of three drain-down time or residence time parameters applied across the network of RAFs. The study demonstrates that the impacts of schemes comprising widely-distributed ensembles of RAFs can be modelled effectively within such a reduced complexity framework. It shows the importance of effective residence times on antecedent conditions in a sequence of events. We discuss uncertainties and limitations introduced by the simplified representation of the overland flow routing and RAF representation and how it could be verified and improved using experimental evidence. We suggest ways in which features could be grouped more strategically and means by which the synchronisation issue could be addressed.

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