A station can only be used for IWR assessment purposes if it represents ambient water quality of surface water and the station can be definitely tagged to one of the 6700 water bodies which we assess. A station will not be in this coverage if it samples wastewater effluent or if it is a rain gauge, or it samples groundwater, etc. Also the station will not be included if it samples a remote piece of water (pond or intermittent stream) that is not part of our water body coverage. These stations are thus the source of data for our IWR assessment that is used in the TMDL process. The majority of our assessment results come from the STORET database, but we also have supplemental data which is not in the STORET database. The majority of this historical supplemental data comes from Legacy STORET, which is not loaded into STORET and was discontinued by EPA as a viable data storage database in 1998 (Note that the IWR process dictates that the water quality data not be older than 10 years old for most of the assessment procedures, therefore, this older Legacy data is not used for these procedures. However, there are assessment procedures which look at older, historic data to determine baseline conditions, so the older data are still used for a few procedures). Also in the supplemental data is WIN data, USGS data, and bioassessment data from SBIO and external biological data submitted to the department for use in the impaired waters assessment.