The cultivation of catch crops has great potential in agricultural areas for the recovery of nutrients, mitigation of groundwater contamination, and secondary utilization of harvestry. To estimate the potential volume of catch crops that can be collected at prospective locations, we simulated the cultivation and collection process at a regional scale using geographic and statistical data. Three types of geographic data, namely the locations of greenhouses, collecting stations and road networks, were used in a geographic information system to compute the volume of collected catch crops and carrying distance between greenhouses and collecting stations. Carbon emission from transportation of the catch crop was calculated using an improved ton‐km method, and the results were compared with the carbon content of the catch crop to evaluate the carbon balance. We found that the total fresh weight of the collected catch crops was 67900 t, of which 70% was collected at the top 15 of 73 stations. Carbon emissions from transportation ranged from >1 to 12% of the carbon content of the catch crop. The analytical method used in this study can readily be applied to other environmental studies concerning the collection of agricultural products and other biomass resources.