Study Target Riparian forest buffer zones (Riparian Ecosystem management model(REMM))
Background • Lands converted to crop fields and have been expanded to the edge of the riverbanks. Then, riverside water pollution reduced the usable water for agriculture and caused a lot of problem. At this time, streamside forest riparian buffer zones play an important role and bring us many benefits (mitigate pollutants, biomass production). Therefore, converting riverside croplands to riparian buffer zone is beneficial and this benefits can be applied into a special water basin.
Objectives • Using REMM, estimate the biomass production and environmental benefits, for converting riverside crop fields to riparian systems.
More Details • Modify and test REMM(Way: field observations and data in literature) for newly constructed riparian ecosystems with short rotation woody biofuel crops; • Construct a spatial database (provide input variables) in Yellow River basin to drive the modified model; • Using model and database to demonstrate the potential biomass production of short rotation crops, and improvement the water quality (by reducing sediments and pollutants in runoff); • Others: examine the scaling issues in applying a field scale to large scale.
Study area: Yellow river basin • Reasons: • 1). Availability of data for evaluating the approach. • 2). Geographical significance (Yellow river basin: food production, natural resources, economic development; Loess plateau: Surface soil erosion produces sediments, precipitation)
Tasks and steps • 1. To tailor, modify and test the model for newly constructed riparian ecosystems with short rotation woody biofuel crops. • 1). REMM: • Using 5 data files to describe: zone and soil characteristics, vegetation, weather, upland loading, and management options. • 2). Choose Willow as the woody biofuel crop, with a 3 year rotation. The characteristics of Willow will be collected from observation and literature data. • 3). Output: The movement of water and sediment, dynamics of carbon, nitrogen, and phosphorous, and biomass production.
• 2. To construct a spatial database at river basin scale, providing key input variables for the simulation, including climate, soil, topography, vegetation, and upland loading • 1). A digital elevation map (DEM) with 1 x 1 km resolution will be used to delineate the sub-basin, stream, and related parameters such as slope and stream width. • 2). Climatic data for each sub-basin will be generated based on surface observations over the past 30 years. • 3). Land use and soil properties are to be obtained from the digital maps created by Chinese Academy of Sciences at a spatial resolution of 1: 4 M. The land use types will be primarily classified into 5 types: crops, forests, grassland, urban, and other land uses uncovered by vegetation. • 4). The upland loading will be parametrized for corn and wheat, the major crops in the Yellow River basin, in the form of carbon, organic N, ammonium, nitrate, and organic and inorganic phosphorous.
• 3. To estimate and demonstrate the biomass production potential and environmental benefits for different conversion scenarios • 1). We will use 10 m, 25 m, and 50 as the proposed width of the buffer strip. Simulations will be conducted at a “mean condition” of the sub-basin in terms of climate, soil type, topography, vegetation, and upland loading. • 2). Chooses 12 reservoirs along the Yellow River in the study domain.
Anticipated results • The assessment of the technical feasibility and parameterization needs for using REMM at river basin scale; • Estimates of potential biomass production and environmental benefits for converting riverbank cropland into riparian ecosystems; • Differences in the performance of the buffer zones with different widths. •
Potential problem • Scaling problems (because REMM is usually used in field scale, its application in watersheds may have scaling problems); • It lacks real data for evaluating the validity of the model.