Abstract The aim of the work is to propose a method to detect the risk of soil erosion areas near the river and the functionality of existing riparian forests as buffers / filters towards the eroded soil from the hill slopes. The proposed methodology has been designed for water pollution control from suspended solids, pollutants and nutrients coming from hills according to different land uses and consequently as an improvement of the quality of the river environment. Suspended sediment yield is known to imply several detrimental consequences: soil losses from agricultural land, worsening of the quality of the water, clogging of water supply filters and reservoir siltation. In addition, suspended sediment yield is also one of the main vectors for pollutants and nutrients: various studies have already proved how nitrogen content has been constantly rising in aquifers and surface waters. Finer particles and their aggregates have been proved to be the preferential vehicle for particulate nitrogen. Soil erosion and Suspended Sediment Yield are strongly related in the Apennines catchments which are generally characterised by a clayey lithology and impermeable lands, extensive and severe erosion and slope stability problems. The suspended sediment yield represents one of the most reliable tools to assess real basin soil loss (Pavanelli and Pagliarani, 2002; Pavanelli and Rigotti, 2007a) from the surface rain erosive features in a mountain watershed, as rills and interrills erosion, gullies, bad-lands (calanchi basins). The problem of controlling the suspended sediment concentration can be tackled by water surface control and increasing the riparian vegetation able to hold back the ground eroded by the slopes, but it is necessary to know where the critical zones are. The stages of the study are to spot critical areas made up of streambank and the eroded areas on the slopes near the river, on a strip buffer of 200 metres, with the support of aerial photos and satellite images, survey and G.I.S.. The methods allow us to detect the quality of the riparian vegetation in comparison to the degree of risk of soil erosion in the hill slope strip buffer. The methodology was applied on the riparian vegetation of the Gaiana torrent (8.6 km2 ), near Bologna, where it was related to soil cover and erosion areas of the hill slope, thus correlating the impact of human activities Finally, the methodology can help us to suggest ways to improve or replant the degraded vegetation on the stream banks, according to multifunctional sylvicoltural models.
D. Pavanelli, C. Cavazza (2009). A method to detect the functionality of riparian vegetation towards soil erosion and river suspended sediment control.. MARRAKECH : Sous le Double Parrainage du Ministère de l’Agricu.
A method to detect the functionality of riparian vegetation towards soil erosion and river suspended sediment control.
PAVANELLI, DONATELLA;CAVAZZA, CLAUDIO
2009
Abstract
Abstract The aim of the work is to propose a method to detect the risk of soil erosion areas near the river and the functionality of existing riparian forests as buffers / filters towards the eroded soil from the hill slopes. The proposed methodology has been designed for water pollution control from suspended solids, pollutants and nutrients coming from hills according to different land uses and consequently as an improvement of the quality of the river environment. Suspended sediment yield is known to imply several detrimental consequences: soil losses from agricultural land, worsening of the quality of the water, clogging of water supply filters and reservoir siltation. In addition, suspended sediment yield is also one of the main vectors for pollutants and nutrients: various studies have already proved how nitrogen content has been constantly rising in aquifers and surface waters. Finer particles and their aggregates have been proved to be the preferential vehicle for particulate nitrogen. Soil erosion and Suspended Sediment Yield are strongly related in the Apennines catchments which are generally characterised by a clayey lithology and impermeable lands, extensive and severe erosion and slope stability problems. The suspended sediment yield represents one of the most reliable tools to assess real basin soil loss (Pavanelli and Pagliarani, 2002; Pavanelli and Rigotti, 2007a) from the surface rain erosive features in a mountain watershed, as rills and interrills erosion, gullies, bad-lands (calanchi basins). The problem of controlling the suspended sediment concentration can be tackled by water surface control and increasing the riparian vegetation able to hold back the ground eroded by the slopes, but it is necessary to know where the critical zones are. The stages of the study are to spot critical areas made up of streambank and the eroded areas on the slopes near the river, on a strip buffer of 200 metres, with the support of aerial photos and satellite images, survey and G.I.S.. The methods allow us to detect the quality of the riparian vegetation in comparison to the degree of risk of soil erosion in the hill slope strip buffer. The methodology was applied on the riparian vegetation of the Gaiana torrent (8.6 km2 ), near Bologna, where it was related to soil cover and erosion areas of the hill slope, thus correlating the impact of human activities Finally, the methodology can help us to suggest ways to improve or replant the degraded vegetation on the stream banks, according to multifunctional sylvicoltural models.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
