Modeling of River Channel Shading as a Factor for Changes in Hydromorphological Conditions of Small Lowland Rivers

Abstract

The ecological water quality in rivers and streams is influenced both by the morphological factors (within the watercourse channel and by the dynamic factors associated with flow), as well as biological factors (connected with the flora and fauna characteristic of its specific area). This paper presents an analysis of the effect of river channel shading by trees and shrubs on hydromorphological changes in a selected reach of the Wełna River, Poland. The analysis was conducted on two adjacent cross-sections (one in a reach lined with trees, the other in an open area with no tree or shrub vegetation). Data were collected during field surveys in the years 2014 and 2019. According to the Water Framework Directive, the Wełna River represents a watercourse with small and average-sized watershed areas, with sand being the dominant substrate of the river bottom. Flow volume, distributions of velocity in the sections, as well as substrate grain-size characteristics and river bottom morphology, were determined based on field measurements. In the study, the leaf area index (LAI) of vegetation was measured in the reach lined with trees, while the number and species composition of macrophytes were determined in the investigated river reaches. Moreover, a digital surface model (DSM) and Geoinformation Information System GIS tools were used to illustrate variability in shading within the tree-lined reach. The DSM model was based on Light Detection and Ranging (LIDAR) data. The results of this study enable us to establish the relationship between river shading by vegetation covering the bank zone, and changes in hydromorphological parameters of the river channel.

Extraction of Water Body Information from Remote Sensing Imagery While Considering Greenness and Wetness Based on Tasseled Cap Transformation

“…Therefore, the use of the model in other regions may produce uncertainty errors. Third, the water surface can be shaded by vegetation covering the bank zone, and then the surface morphology of extracted water body information is affected [85][86][87]. Therefore, considering the characteristics of smooth edges of banks, edge restoration of extracted water body information is also worth discussing.…”

Biomass Production Potential in a River under Climate Change Scenarios

“…The spatial analysis revealed elevated values of the TN and TP loads already at the source of the river, which resulted mainly from the connection of the Nielba River source with the heavily polluted Stępuchowskie Lake through the system of canals ( Figure S2 ). However, intensive agriculture and lack of proper wastewater management also play important roles in the nutrient delivery in this basin, 77 which is clearly visible as a rapid increase in nutrient loads in the upper part of the river from the source to the discharge into the Łękno Lake is seen. The Nielba River displays a snow-rain hydrological regime that controls temporal variability of contaminant loads.…”

AHP as a Useful Tool in the Assessment of the Technical Condition of Hydrotechnical Constructions

“…Wełna River is classified as a lowland river and is located on the territory of Wielkopolska Voivodeship in Poland. Its sources are located on a lake area 10 km north-east of Gniezno, and the total length of this river is 118 km [50]. The area of the Wełna catchment area reaches 2621.1 km 2 , while the average surface runoff from its area is 4.08 dm 3 •s −1 •km −2 .…”