In order to perform non-point source modeling using WinHSPF model by BASINS, local meteorological data is required. The current version of BASINS contains an average of 10 meteorological stations per state. The data is stored in the Watershed Data Management (WDM) format, which is used by both BASINS and HSPF. The WDM files and its code library, together provide a powerful tool for managing and manipulating time-series data. However, it requires a significant level of user education to create and deal with the WDM files. A straight forward, easy-to-use tool would greatly benefit the BASINS users in updating or building WDM meteorological files without learning the detailed logistics of WDM operations. To address this issue WDM Toolkit was developed.

The objective of the WDM Toolkit program is to allow users to quickly create time series data or read data from an existing WDM file, edit and perform basic mathematical operations, and report data in graphical and tabular forms. WDM Toolkit allows the users to add available local meteorological data thus removing the existing dependency on the limited set of data stored in BASINS.