A bilingual user's guide for the decision support tool for managing re-vegetation and its impact on hydrology (ReVegIH) in the Coarse Sandy Hilly Catchments of the Loess Plateau, China

[摘要] Executive Summary:In order to reduce the massive soil erosion in the 113,000 km2 Coarse Sandy Hilly Catchments (CSHC) of the Loess Plateau, China, vast expanses of land have been, or are planned, for re-vegetation with deep-rooted perennial species.This re-vegetation process will not only result in less soil erosion in the CSHC, but also less runoff due to increased evapotranspiration (ET).The impact on surface hydrology has, until now, been largely ignored in the implementation of the re-vegetation policy, even though water is a critical resource driving food security in support of the hundreds of millions of people in the region.To address this issue, the Australian Centre for International Agricultural Research (ACIAR) Project LWR/2002/018 was developed to further understand this regional eco-hydrologic process and most importantly, to provide mid to senior policy makers and soil and water managers at national, regional and local scales of governance iwht information to make better decisions.This technology transfer is primarily performed through a bilingual software application called Re-Vegetation Impacts on Hydrology (ReVegIH).This report describes the various options and datasets available in ReVegIH and provides a guide to its users.ReVegIH, which was developed in Microsoft's .NET environment using C# calling some TIME (The Invisible Modelling Environment) functions, is a stand alone application that provides baseic Geographical Information System (GIS) functions so users do not need to install proprietary GIS software.The application provides a spatial scenario modelling capability for stakeholders to better manage their environment.ReVegIH provides managers and both decision and policy makers access to an eco-hydrological modelling capacity at 100 m resolution and to maximise usability, all required datasets are packaged as part of ReVegIH.Through the application, users can estimate impacts of different re-vegetation schemes on runoff and ET in the CSHC by selecting either 1 of the predefined 42 catchments or 1 of the 70 predefined counties that contribute to the CSHC.The underlying annual average rainfall-runoff model used in ReVegIH was originally developed by CSIRO Land and Water using a global dataset and it has been calibrated locally for the CSHC.The model partitions long-term annual average precipitation into annual average ET and annual average runoff as a function of percentage woody perennials in a catchment.Additionally, over the entire CSHC (and for any selected catchment or county) users can spatially identify (at 100m resolution) re-vegetation target areas, priority areas and the suiability of planting conditions for 38 vegetation species, both trees and shrubs; fruit trees that may provide additional economic returns to farmers are also identified.The hydrologic impact of selecting any combination of target (or priority) re-vegetation areas limited by current landuses is also modelled on a catchment or county basis.Re-vegetation priority areas are those cells located in a target area that are both lower than and adjacent to steep slopes and gullies.The combined effect of re-planting the priority zones first will be that the water loss will be minimised while maximising the reduciton of soil entering the river network.ReVegIH provides the ability to view one raster dataset while gaining information from another.For example, we anticipate that the predominant use of ReVegIH will be to display the re-vegetation dataset (showing the target level/priority area in combination with two pre-defined land-limits) while overlaying and exploring information of vegetation suitability for the 38 species.Using ReVegIH in this manner provides users with: (1) a spatial assessment (at a 100 m resolution) of where to, and where not to, re-vegetate with perennial species; (2) seven different site suitability mapping options from the list of 38 species; and (3) estimation of re-vegetation scanario's impact on regional hydrology.the project team recommend that some detailed site assessment be undertaken prior to performing any re-planting as ReVegIH is a regional scale decision support tool, and local factors (near and below the resolution of the data used in the application) may be critical in determining success (or failure) of re-vegetation schemes.

[发布机构] CSIRO Land & Water

[学科分类] 地球科学(综合)