Pressures and threats to an ecosystem and its function need to be predicted and quantified: only knowing them, actions can be taken to avoid them. This is particularly true when the pressures are created by human actions and decisions. Part of these pressures causes changes in a) the water (and sediment) regime, b) the input of water and sediment into given parts of an ecosystem and c) water availability. These impacts can be estimated by means of a simple runoff-erosion model, easy to use and to understand and linked to a spatially distributed description of the landscape where the ecosystem to protect and conserve is located. The model that has been developed (LANDPLANER from “Landscape, plants, landslides and erosion”) has been developed within the framework of EC project SPACE-2010-1 – 263435 – BIO_SOS “BIOdiversity Multi-Source Monitoring System: from Space to Species”. It is a spatially distributed model which simulates runoff, infiltration and sediment fluxes in the landscape. Written in R, LANDPLANER is based on a series of preexisting models/modules so that it can take advantage of existing knowledge (tables, algorithms) characterizing soil/vegetation/landuse response to daily rainfall. The main models/modules on which LANDPLANER is based are: 1) a particular application of the NRCS Runoff Curve Number (RCN) method (HAWKINS et al. 2009); 2) an EUROSEMbased sediment generation routine (MORGAN et al. 1998, DEBAETS et al. 2008, SMETS et al. 2010), and 3) an overland flow direction and accumulation routine as developed in GRASS (© GRASS Development Team, 1998-2013). LANDPLANER builds on these models and adds: 1) a simplified multi-layers routine for infiltrating water into the soil; 2) a modification of flow direction and accumulation imposing roads and other structures as modification of the real DTM; and 3) and identification of the areas subject to gully erosion (from ephemeral gullies to retreating-eroding gullies) based on a deep modification of the topographical thresholds equation for gullyhead (MONTGOMERY & DIETRICH 1994, POESEN et al. 2011) and the introduction of the effect of vegetation, land use, and soil in the definition of the threshold conditions. LANDPLANER allows analyses such as: which is the water amount that actually can reach a given spot (e.g., a pond with amphibians) and from which area is the water coming under the prevailing meteo conditions, land use, morphology etc.; hence, if we add a road cutting through the overland flow source area, how will runoff harvesting change at the pond? Can we build the road without impacting negatively? Sediments too can have positive/negative effects, e.g. silt the pond. Where do they come from? Can we decrease the sediment input (to the pond) to an acceptable quantity? How can we do it without changing runoff harvesting? And if there is a wildfire, how will the situation change?
BIO_SOS Modelling Activities: Modelling Runoff-Sediment Connectivity
BACARO, Giovanni;
2013-01-01
Abstract
Pressures and threats to an ecosystem and its function need to be predicted and quantified: only knowing them, actions can be taken to avoid them. This is particularly true when the pressures are created by human actions and decisions. Part of these pressures causes changes in a) the water (and sediment) regime, b) the input of water and sediment into given parts of an ecosystem and c) water availability. These impacts can be estimated by means of a simple runoff-erosion model, easy to use and to understand and linked to a spatially distributed description of the landscape where the ecosystem to protect and conserve is located. The model that has been developed (LANDPLANER from “Landscape, plants, landslides and erosion”) has been developed within the framework of EC project SPACE-2010-1 – 263435 – BIO_SOS “BIOdiversity Multi-Source Monitoring System: from Space to Species”. It is a spatially distributed model which simulates runoff, infiltration and sediment fluxes in the landscape. Written in R, LANDPLANER is based on a series of preexisting models/modules so that it can take advantage of existing knowledge (tables, algorithms) characterizing soil/vegetation/landuse response to daily rainfall. The main models/modules on which LANDPLANER is based are: 1) a particular application of the NRCS Runoff Curve Number (RCN) method (HAWKINS et al. 2009); 2) an EUROSEMbased sediment generation routine (MORGAN et al. 1998, DEBAETS et al. 2008, SMETS et al. 2010), and 3) an overland flow direction and accumulation routine as developed in GRASS (© GRASS Development Team, 1998-2013). LANDPLANER builds on these models and adds: 1) a simplified multi-layers routine for infiltrating water into the soil; 2) a modification of flow direction and accumulation imposing roads and other structures as modification of the real DTM; and 3) and identification of the areas subject to gully erosion (from ephemeral gullies to retreating-eroding gullies) based on a deep modification of the topographical thresholds equation for gullyhead (MONTGOMERY & DIETRICH 1994, POESEN et al. 2011) and the introduction of the effect of vegetation, land use, and soil in the definition of the threshold conditions. LANDPLANER allows analyses such as: which is the water amount that actually can reach a given spot (e.g., a pond with amphibians) and from which area is the water coming under the prevailing meteo conditions, land use, morphology etc.; hence, if we add a road cutting through the overland flow source area, how will runoff harvesting change at the pond? Can we build the road without impacting negatively? Sediments too can have positive/negative effects, e.g. silt the pond. Where do they come from? Can we decrease the sediment input (to the pond) to an acceptable quantity? How can we do it without changing runoff harvesting? And if there is a wildfire, how will the situation change?Pubblicazioni consigliate
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